gdb_server.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   Copyright (C) 2005 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2007-2010 Øyvind Harboe                                 *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   Copyright (C) 2008 by Spencer Oliver                                  *
 *   spen@spen-soft.co.uk                                                  *
 *                                                                         *
 *   Copyright (C) 2011 by Broadcom Corporation                            *
 *   Evan Hunter - ehunter@broadcom.com                                    *
 *                                                                         *
 *   Copyright (C) ST-Ericsson SA 2011                                     *
 *   michel.jaouen@stericsson.com : smp minimum support                    *
 *                                                                         *
 *   Copyright (C) 2013 Andes Technology                                   *
 *   Hsiangkai Wang <hkwang@andestech.com>                                 *
 *                                                                         *
 *   Copyright (C) 2013 Franck Jullien                                     *
 *   elec4fun@gmail.com                                                    *
 ***************************************************************************/
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include <target/breakpoints.h>
#include <target/target_request.h>
#include <target/register.h>
#include <target/target.h>
#include <target/target_type.h>
#include <target/semihosting_common.h>
#include "server.h"
#include <flash/nor/core.h>
#include "gdb_server.h"
#include <target/image.h>
#include <jtag/jtag.h>
#include "rtos/rtos.h"
#include "target/smp.h"
 
#define CTRL(c) ((c) - '@')
 
enum gdb_output_flag {
    /* GDB doesn't accept 'O' packets */
    GDB_OUTPUT_NO,
    /* GDB doesn't accept 'O' packets but accepts notifications */
    GDB_OUTPUT_NOTIF,
    /* GDB accepts 'O' packets */
    GDB_OUTPUT_ALL,
};
 
struct target_desc_format {
    char *tdesc;
    uint32_t tdesc_length;
};
 
/* private connection data for GDB */
struct gdb_connection {
    char buffer[GDB_BUFFER_SIZE + 1]; /* Extra byte for null-termination */
    char *buf_p;
    int buf_cnt;
    bool ctrl_c;
    enum target_state frontend_state;
    struct image *vflash_image;
    bool closed;
    /* set to prevent re-entrance from log messages during gdb_get_packet()
     * and gdb_put_packet(). */
    bool busy;
    int noack_mode;
    /* set flag to true if you want the next stepi to return immediately.
     * allowing GDB to pick up a fresh set of register values from the target
     * without modifying the target state. */
    bool sync;
    /* We delay reporting memory write errors until next step/continue or memory
     * write. This improves performance of gdb load significantly as the GDB packet
     * can be replied immediately and a new GDB packet will be ready without delay
     * (ca. 10% or so...). */
    bool mem_write_error;
    /* with extended-remote it seems we need to better emulate attach/detach.
     * what this means is we reply with a W stop reply after a kill packet,
     * normally we reply with a S reply via gdb_last_signal_packet.
     * as a side note this behaviour only effects gdb > 6.8 */
    bool attached;
    /* set when extended protocol is used */
    bool extended_protocol;
    /* temporarily used for target description support */
    struct target_desc_format target_desc;
    /* temporarily used for thread list support */
    char *thread_list;
    /* flag to mask the output from gdb_log_callback() */
    enum gdb_output_flag output_flag;
    /* Unique index for this GDB connection. */
    unsigned int unique_index;
};
 
#if 0
#define _DEBUG_GDB_IO_
#endif
 
static struct gdb_connection *current_gdb_connection;
 
static int gdb_breakpoint_override;
static enum breakpoint_type gdb_breakpoint_override_type;
 
static int gdb_error(struct connection *connection, int retval);
static char *gdb_port;
static char *gdb_port_next;
 
static void gdb_log_callback(void *priv, const char *file, unsigned int line,
        const char *function, const char *string);
 
static void gdb_sig_halted(struct connection *connection);
 
/* number of gdb connections, mainly to suppress gdb related debugging spam
 * in helper/log.c when no gdb connections are actually active */
static int gdb_actual_connections;
 
/* set if we are sending a memory map to gdb
 * via qXfer:memory-map:read packet */
/* enabled by default*/
static bool gdb_use_memory_map = true;
/* enabled by default*/
static bool gdb_flash_program = true;
 
/* if set, data aborts cause an error to be reported in memory read packets
 * see the code in gdb_read_memory_packet() for further explanations.
 * Disabled by default.
 */
static int gdb_report_data_abort;
/* If set, errors when accessing registers are reported to gdb. Disabled by
 * default. */
static int gdb_report_register_access_error;
 
/* set if we are sending target descriptions to gdb
 * via qXfer:features:read packet */
/* enabled by default */
static bool gdb_use_target_description = true;
 
/* current processing free-run type, used by file-I/O */
static char gdb_running_type;
 
/* Find an available target in the SMP group that gdb is connected to. For
 * commands that affect an entire SMP group (like memory access and run control)
 * this will give better results than returning the unavailable target and having
 * the command fail.  If gdb was aware that targets can be unavailable we
 * wouldn't need this logic.
 */
struct target *get_available_target_from_connection(struct connection *connection)
{
    struct gdb_service *gdb_service = connection->service->priv;
    struct target *target = gdb_service->target;
    if (target->state == TARGET_UNAVAILABLE && target->smp) {
        struct target_list *tlist;
        foreach_smp_target(tlist, target->smp_targets) {
            struct target *t = tlist->target;
            if (t->state != TARGET_UNAVAILABLE)
                return t;
        }
        /* If we can't find an available target, just return the
         * original. */
    }
    return target;
}
 
static int gdb_last_signal(struct target *target)
{
    LOG_TARGET_DEBUG(target, "Debug reason is: %s",
            target_debug_reason_str(target->debug_reason));
 
    switch (target->debug_reason) {
        case DBG_REASON_DBGRQ:
            return 0x2;     /* SIGINT */
        case DBG_REASON_BREAKPOINT:
        case DBG_REASON_WATCHPOINT:
        case DBG_REASON_WPTANDBKPT:
            return 0x05;    /* SIGTRAP */
        case DBG_REASON_SINGLESTEP:
            return 0x05;    /* SIGTRAP */
        case DBG_REASON_EXC_CATCH:
            return 0x05;
        case DBG_REASON_NOTHALTED:
            return 0x0;     /* no signal... shouldn't happen */
        default:
            LOG_USER("undefined debug reason %d (%s) - target needs reset",
                    target->debug_reason,
                    target_debug_reason_str(target->debug_reason));
            return 0x0;
    }
}
 
static int check_pending(struct connection *connection,
        int timeout_s, int *got_data)
{
    /* a non-blocking socket will block if there is 0 bytes available on the socket,
     * but return with as many bytes as are available immediately
     */
    struct timeval tv;
    fd_set read_fds;
    struct gdb_connection *gdb_con = connection->priv;
    int t;
    if (!got_data)
        got_data = &t;
    *got_data = 0;
 
    if (gdb_con->buf_cnt > 0) {
        *got_data = 1;
        return ERROR_OK;
    }
 
    FD_ZERO(&read_fds);
    FD_SET(connection->fd, &read_fds);
 
    tv.tv_sec = timeout_s;
    tv.tv_usec = 0;
    if (socket_select(connection->fd + 1, &read_fds, NULL, NULL, &tv) == 0) {
        /* This can typically be because a "monitor" command took too long
         * before printing any progress messages
         */
        if (timeout_s > 0)
            return ERROR_GDB_TIMEOUT;
        else
            return ERROR_OK;
    }
    *got_data = FD_ISSET(connection->fd, &read_fds) != 0;
    return ERROR_OK;
}
 
static int gdb_get_char_inner(struct connection *connection, int *next_char)
{
    struct gdb_connection *gdb_con = connection->priv;
    int retval = ERROR_OK;
 
#ifdef _DEBUG_GDB_IO_
    char *debug_buffer;
#endif
    for (;; ) {
        if (connection->service->type != CONNECTION_TCP)
            gdb_con->buf_cnt = read(connection->fd, gdb_con->buffer, GDB_BUFFER_SIZE);
        else {
            retval = check_pending(connection, 1, NULL);
            if (retval != ERROR_OK)
                return retval;
            gdb_con->buf_cnt = read_socket(connection->fd,
                    gdb_con->buffer,
                    GDB_BUFFER_SIZE);
        }
 
        if (gdb_con->buf_cnt > 0)
            break;
        if (gdb_con->buf_cnt == 0) {
            LOG_DEBUG("GDB connection closed by the remote client");
            gdb_con->closed = true;
            return ERROR_SERVER_REMOTE_CLOSED;
        }
 
#ifdef _WIN32
        bool retry = (WSAGetLastError() == WSAEWOULDBLOCK);
#else
        bool retry = (errno == EAGAIN);
#endif
 
        if (retry) {
            // Try again after a delay
            usleep(1000);
        } else {
            // Print error and close the socket
            log_socket_error("GDB");
            gdb_con->closed = true;
            return ERROR_SERVER_REMOTE_CLOSED;
        }
    }
 
#ifdef _DEBUG_GDB_IO_
    debug_buffer = strndup(gdb_con->buffer, gdb_con->buf_cnt);
    LOG_DEBUG("received '%s'", debug_buffer);
    free(debug_buffer);
#endif
 
    gdb_con->buf_p = gdb_con->buffer;
    gdb_con->buf_cnt--;
    *next_char = *(gdb_con->buf_p++);
    if (gdb_con->buf_cnt > 0)
        connection->input_pending = true;
    else
        connection->input_pending = false;
#ifdef _DEBUG_GDB_IO_
    LOG_DEBUG("returned char '%c' (0x%2.2x)", *next_char, *next_char);
#endif
 
    return retval;
}
 
static inline int gdb_get_char_fast(struct connection *connection,
        int *next_char, char **buf_p, int *buf_cnt)
{
    int retval = ERROR_OK;
 
    if ((*buf_cnt)-- > 0) {
        *next_char = **buf_p;
        (*buf_p)++;
        if (*buf_cnt > 0)
            connection->input_pending = true;
        else
            connection->input_pending = false;
 
#ifdef _DEBUG_GDB_IO_
        LOG_DEBUG("returned char '%c' (0x%2.2x)", *next_char, *next_char);
#endif
 
        return ERROR_OK;
    }
 
    struct gdb_connection *gdb_con = connection->priv;
    gdb_con->buf_p = *buf_p;
    gdb_con->buf_cnt = *buf_cnt;
    retval = gdb_get_char_inner(connection, next_char);
    *buf_p = gdb_con->buf_p;
    *buf_cnt = gdb_con->buf_cnt;
 
    return retval;
}
 
static int gdb_get_char(struct connection *connection, int *next_char)
{
    struct gdb_connection *gdb_con = connection->priv;
    return gdb_get_char_fast(connection, next_char, &gdb_con->buf_p, &gdb_con->buf_cnt);
}
 
static int gdb_putback_char(struct connection *connection, int last_char)
{
    struct gdb_connection *gdb_con = connection->priv;
 
    if (gdb_con->buf_p > gdb_con->buffer) {
        *(--gdb_con->buf_p) = last_char;
        gdb_con->buf_cnt++;
    } else
        LOG_ERROR("BUG: couldn't put character back");
 
    return ERROR_OK;
}
 
/* The only way we can detect that the socket is closed is the first time
 * we write to it, we will fail. Subsequent write operations will
 * succeed. Shudder! */
static int gdb_write(struct connection *connection, const void *data, int len)
{
    struct gdb_connection *gdb_con = connection->priv;
    if (gdb_con->closed) {
        LOG_DEBUG("GDB socket marked as closed, cannot write to it.");
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    if (connection_write(connection, data, len) == len)
        return ERROR_OK;
 
    LOG_WARNING("Error writing to GDB socket. Dropping the connection.");
    gdb_con->closed = true;
    return ERROR_SERVER_REMOTE_CLOSED;
}
 
static void gdb_log_incoming_packet(struct connection *connection, const char *packet)
{
    if (!LOG_LEVEL_IS(LOG_LVL_DEBUG))
        return;
 
    struct target *target = get_target_from_connection(connection);
    struct gdb_connection *gdb_connection = connection->priv;
 
    /* Avoid dumping non-printable characters to the terminal */
    const unsigned int packet_len = strlen(packet);
    const char *nonprint = find_nonprint_char(packet, packet_len);
    if (nonprint) {
        /* Does packet at least have a prefix that is printable?
         * Look within the first 50 chars of the packet. */
        const char *colon = memchr(packet, ':', MIN(50, packet_len));
        const bool packet_has_prefix = (colon);
        const bool packet_prefix_printable = (packet_has_prefix && nonprint > colon);
 
        if (packet_prefix_printable) {
            const unsigned int prefix_len = colon - packet + 1;  /* + 1 to include the ':' */
            const unsigned int payload_len = packet_len - prefix_len;
            LOG_TARGET_DEBUG(target, "{%d} received packet: %.*s<binary-data-%u-bytes>",
                gdb_connection->unique_index, prefix_len, packet, payload_len);
        } else {
            LOG_TARGET_DEBUG(target, "{%d} received packet: <binary-data-%u-bytes>",
                gdb_connection->unique_index, packet_len);
        }
    } else {
        /* All chars printable, dump the packet as is */
        LOG_TARGET_DEBUG(target, "{%d} received packet: %s", gdb_connection->unique_index, packet);
    }
}
 
static void gdb_log_outgoing_packet(struct connection *connection, const char *packet_buf,
    unsigned int packet_len, unsigned char checksum)
{
    if (!LOG_LEVEL_IS(LOG_LVL_DEBUG))
        return;
 
    struct target *target = get_target_from_connection(connection);
    struct gdb_connection *gdb_connection = connection->priv;
 
    if (find_nonprint_char(packet_buf, packet_len))
        LOG_TARGET_DEBUG(target, "{%d} sending packet: $<binary-data-%u-bytes>#%2.2x",
            gdb_connection->unique_index, packet_len, checksum);
    else
        LOG_TARGET_DEBUG(target, "{%d} sending packet: $%.*s#%2.2x",
            gdb_connection->unique_index, packet_len, packet_buf, checksum);
}
 
static int gdb_put_packet_inner(struct connection *connection,
        const char *buffer, int len)
{
    int i;
    unsigned char my_checksum = 0;
    int reply;
    int retval;
    struct gdb_connection *gdb_con = connection->priv;
 
    for (i = 0; i < len; i++)
        my_checksum += buffer[i];
 
#ifdef _DEBUG_GDB_IO_
    /*
     * At this point we should have nothing in the input queue from GDB,
     * however sometimes '-' is sent even though we've already received
     * an ACK (+) for everything we've sent off.
     */
    int gotdata;
    for (;; ) {
        retval = check_pending(connection, 0, &gotdata);
        if (retval != ERROR_OK)
            return retval;
        if (!gotdata)
            break;
        retval = gdb_get_char(connection, &reply);
        if (retval != ERROR_OK)
            return retval;
        if (reply == '$') {
            /* fix a problem with some IAR tools */
            gdb_putback_char(connection, reply);
            LOG_DEBUG("Unexpected start of new packet");
            break;
        } else if (reply == CTRL('C')) {
            /* do not discard Ctrl-C */
            gdb_putback_char(connection, reply);
            break;
        }
 
        LOG_WARNING("Discard unexpected char %c", reply);
    }
#endif
 
    while (1) {
        gdb_log_outgoing_packet(connection, buffer, len, my_checksum);
 
        char local_buffer[1024];
        local_buffer[0] = '$';
        if ((size_t)len + 5 <= sizeof(local_buffer)) {
            /* performance gain on smaller packets by only a single call to gdb_write() */
            memcpy(local_buffer + 1, buffer, len++);
            len += snprintf(local_buffer + len, sizeof(local_buffer) - len, "#%02x", my_checksum);
            retval = gdb_write(connection, local_buffer, len);
            if (retval != ERROR_OK)
                return retval;
        } else {
            /* larger packets are transmitted directly from caller supplied buffer
             * by several calls to gdb_write() to avoid dynamic allocation */
            snprintf(local_buffer + 1, sizeof(local_buffer) - 1, "#%02x", my_checksum);
            retval = gdb_write(connection, local_buffer, 1);
            if (retval != ERROR_OK)
                return retval;
            retval = gdb_write(connection, buffer, len);
            if (retval != ERROR_OK)
                return retval;
            retval = gdb_write(connection, local_buffer + 1, 3);
            if (retval != ERROR_OK)
                return retval;
        }
 
        if (gdb_con->noack_mode)
            break;
 
        retval = gdb_get_char(connection, &reply);
        if (retval != ERROR_OK)
            return retval;
 
        if (reply == '+') {
            gdb_log_incoming_packet(connection, "+");
            break;
        } else if (reply == '-') {
            /* Stop sending output packets for now */
            gdb_con->output_flag = GDB_OUTPUT_NO;
            gdb_log_incoming_packet(connection, "-");
            LOG_WARNING("negative reply, retrying");
        } else if (reply == CTRL('C')) {
            gdb_con->ctrl_c = true;
            gdb_log_incoming_packet(connection, "<Ctrl-C>");
            retval = gdb_get_char(connection, &reply);
            if (retval != ERROR_OK)
                return retval;
            if (reply == '+') {
                gdb_log_incoming_packet(connection, "+");
                break;
            } else if (reply == '-') {
                /* Stop sending output packets for now */
                gdb_con->output_flag = GDB_OUTPUT_NO;
                gdb_log_incoming_packet(connection, "-");
                LOG_WARNING("negative reply, retrying");
            } else if (reply == '$') {
                LOG_ERROR("GDB missing ack(1) - assumed good");
                gdb_putback_char(connection, reply);
                return ERROR_OK;
            } else {
                LOG_ERROR("unknown character(1) 0x%2.2x in reply, dropping connection", reply);
                gdb_con->closed = true;
                return ERROR_SERVER_REMOTE_CLOSED;
            }
        } else if (reply == '$') {
            LOG_ERROR("GDB missing ack(2) - assumed good");
            gdb_putback_char(connection, reply);
            return ERROR_OK;
        } else {
            LOG_ERROR("unknown character(2) 0x%2.2x in reply, dropping connection",
                reply);
            gdb_con->closed = true;
            return ERROR_SERVER_REMOTE_CLOSED;
        }
    }
    if (gdb_con->closed)
        return ERROR_SERVER_REMOTE_CLOSED;
 
    return ERROR_OK;
}
 
int gdb_put_packet(struct connection *connection, const char *buffer, int len)
{
    struct gdb_connection *gdb_con = connection->priv;
    gdb_con->busy = true;
    int retval = gdb_put_packet_inner(connection, buffer, len);
    gdb_con->busy = false;
 
    /* we sent some data, reset timer for keep alive messages */
    kept_alive();
 
    return retval;
}
 
static inline int fetch_packet(struct connection *connection,
        int *checksum_ok, int noack, int *len, char *buffer)
{
    unsigned char my_checksum = 0;
    char checksum[3];
    int character;
    int retval = ERROR_OK;
 
    struct gdb_connection *gdb_con = connection->priv;
    my_checksum = 0;
    int count = 0;
    count = 0;
 
    /* move this over into local variables to use registers and give the
     * more freedom to optimize */
    char *buf_p = gdb_con->buf_p;
    int buf_cnt = gdb_con->buf_cnt;
 
    for (;; ) {
        /* The common case is that we have an entire packet with no escape chars.
         * We need to leave at least 2 bytes in the buffer to have
         * gdb_get_char() update various bits and bobs correctly.
         */
        if ((buf_cnt > 2) && ((buf_cnt + count) < *len)) {
            /* The compiler will struggle a bit with constant propagation and
             * aliasing, so we help it by showing that these values do not
             * change inside the loop
             */
            int i;
            char *buf = buf_p;
            int run = buf_cnt - 2;
            i = 0;
            int done = 0;
            while (i < run) {
                character = *buf++;
                i++;
                if (character == '#') {
                    /* Danger! character can be '#' when esc is
                     * used so we need an explicit boolean for done here. */
                    done = 1;
                    break;
                }
 
                if (character == '}') {
                    /* data transmitted in binary mode (X packet)
                     * uses 0x7d as escape character */
                    my_checksum += character & 0xff;
                    character = *buf++;
                    i++;
                    my_checksum += character & 0xff;
                    buffer[count++] = (character ^ 0x20) & 0xff;
                } else {
                    my_checksum += character & 0xff;
                    buffer[count++] = character & 0xff;
                }
            }
            buf_p += i;
            buf_cnt -= i;
            if (done)
                break;
        }
        if (count > *len) {
            LOG_ERROR("packet buffer too small");
            retval = ERROR_GDB_BUFFER_TOO_SMALL;
            break;
        }
 
        retval = gdb_get_char_fast(connection, &character, &buf_p, &buf_cnt);
        if (retval != ERROR_OK)
            break;
 
        if (character == '#')
            break;
 
        if (character == '}') {
            /* data transmitted in binary mode (X packet)
             * uses 0x7d as escape character */
            my_checksum += character & 0xff;
 
            retval = gdb_get_char_fast(connection, &character, &buf_p, &buf_cnt);
            if (retval != ERROR_OK)
                break;
 
            my_checksum += character & 0xff;
            buffer[count++] = (character ^ 0x20) & 0xff;
        } else {
            my_checksum += character & 0xff;
            buffer[count++] = character & 0xff;
        }
    }
 
    gdb_con->buf_p = buf_p;
    gdb_con->buf_cnt = buf_cnt;
 
    if (retval != ERROR_OK)
        return retval;
 
    *len = count;
 
    retval = gdb_get_char(connection, &character);
    if (retval != ERROR_OK)
        return retval;
    checksum[0] = character;
    retval = gdb_get_char(connection, &character);
    if (retval != ERROR_OK)
        return retval;
    checksum[1] = character;
    checksum[2] = 0;
 
    if (!noack)
        *checksum_ok = (my_checksum == strtoul(checksum, NULL, 16));
 
    return ERROR_OK;
}
 
static int gdb_get_packet_inner(struct connection *connection,
        char *buffer, int *len)
{
    int character;
    int retval;
    struct gdb_connection *gdb_con = connection->priv;
 
    while (1) {
        do {
            retval = gdb_get_char(connection, &character);
            if (retval != ERROR_OK)
                return retval;
 
#ifdef _DEBUG_GDB_IO_
            LOG_DEBUG("character: '%c'", character);
#endif
 
            switch (character) {
                case '$':
                    break;
                case '+':
                    gdb_log_incoming_packet(connection, "+");
                    /* According to the GDB documentation
                     * (https://sourceware.org/gdb/onlinedocs/gdb/Packet-Acknowledgment.html):
                     * "gdb sends a final `+` acknowledgment of the stub's `OK`
                     * response, which can be safely ignored by the stub."
                     * However OpenOCD server already is in noack mode at this
                     * point and instead of ignoring this it was emitting a
                     * warning. This code makes server ignore the first ACK
                     * that will be received after going into noack mode,
                     * warning only about subsequent ACK's. */
                    if (gdb_con->noack_mode > 1) {
                        LOG_WARNING("acknowledgment received, but no packet pending");
                    } else if (gdb_con->noack_mode) {
                        LOG_DEBUG("Received first acknowledgment after entering noack mode. Ignoring it.");
                        gdb_con->noack_mode = 2;
                    }
                    break;
                case '-':
                    gdb_log_incoming_packet(connection, "-");
                    LOG_WARNING("negative acknowledgment, but no packet pending");
                    break;
                case CTRL('C'):
                    gdb_log_incoming_packet(connection, "<Ctrl-C>");
                    gdb_con->ctrl_c = true;
                    *len = 0;
                    return ERROR_OK;
                default:
                    LOG_WARNING("ignoring character 0x%x", character);
                    break;
            }
        } while (character != '$');
 
        int checksum_ok = 0;
        /* explicit code expansion here to get faster inlined code in -O3 by not
         * calculating checksum */
        if (gdb_con->noack_mode) {
            retval = fetch_packet(connection, &checksum_ok, 1, len, buffer);
            if (retval != ERROR_OK)
                return retval;
        } else {
            retval = fetch_packet(connection, &checksum_ok, 0, len, buffer);
            if (retval != ERROR_OK)
                return retval;
        }
 
        if (gdb_con->noack_mode) {
            /* checksum is not checked in noack mode */
            break;
        }
        if (checksum_ok) {
            retval = gdb_write(connection, "+", 1);
            if (retval != ERROR_OK)
                return retval;
            break;
        }
    }
    if (gdb_con->closed)
        return ERROR_SERVER_REMOTE_CLOSED;
 
    return ERROR_OK;
}
 
static int gdb_get_packet(struct connection *connection, char *buffer, int *len)
{
    struct gdb_connection *gdb_con = connection->priv;
    gdb_con->busy = true;
    int retval = gdb_get_packet_inner(connection, buffer, len);
    gdb_con->busy = false;
    return retval;
}
 
static int gdb_output_con(struct connection *connection, const char *line)
{
    char *hex_buffer;
    int bin_size;
 
    bin_size = strlen(line);
 
    hex_buffer = malloc(bin_size * 2 + 2);
    if (!hex_buffer)
        return ERROR_GDB_BUFFER_TOO_SMALL;
 
    hex_buffer[0] = 'O';
    size_t pkt_len = hexify(hex_buffer + 1, (const uint8_t *)line, bin_size,
        bin_size * 2 + 1);
    int retval = gdb_put_packet(connection, hex_buffer, pkt_len + 1);
 
    free(hex_buffer);
    return retval;
}
 
static int gdb_output(struct command_context *context, const char *line)
{
    /* this will be dumped to the log and also sent as an O packet if possible */
    LOG_USER_N("%s", line);
    return ERROR_OK;
}
 
static void gdb_signal_reply(struct target *target, struct connection *connection)
{
    struct gdb_connection *gdb_connection = connection->priv;
    char sig_reply[65];
    char stop_reason[32];
    char current_thread[25];
    int sig_reply_len;
    int signal_var;
 
    rtos_update_threads(target);
 
    if (target->debug_reason == DBG_REASON_EXIT) {
        sig_reply_len = snprintf(sig_reply, sizeof(sig_reply), "W00");
    } else {
        struct target *ct;
        struct rtos *rtos;
 
        rtos = rtos_from_target(target);
        if (rtos) {
            rtos->current_threadid = rtos->current_thread;
            rtos->gdb_target_for_threadid(connection, rtos->current_threadid, &ct);
        } else {
            ct = target;
        }
 
        if (gdb_connection->ctrl_c) {
            LOG_TARGET_DEBUG(target, "Responding with signal 2 (SIGINT) to debugger due to Ctrl-C");
            signal_var = 0x2;
        } else
            signal_var = gdb_last_signal(ct);
 
        stop_reason[0] = '\0';
        if (ct->debug_reason == DBG_REASON_WATCHPOINT) {
            enum watchpoint_rw hit_wp_type;
            target_addr_t hit_wp_address;
 
            if (watchpoint_hit(ct, &hit_wp_type, &hit_wp_address) == ERROR_OK) {
 
                switch (hit_wp_type) {
                    case WPT_WRITE:
                        snprintf(stop_reason, sizeof(stop_reason),
                                "watch:%08" TARGET_PRIxADDR ";", hit_wp_address);
                        break;
                    case WPT_READ:
                        snprintf(stop_reason, sizeof(stop_reason),
                                "rwatch:%08" TARGET_PRIxADDR ";", hit_wp_address);
                        break;
                    case WPT_ACCESS:
                        snprintf(stop_reason, sizeof(stop_reason),
                                "awatch:%08" TARGET_PRIxADDR ";", hit_wp_address);
                        break;
                    default:
                        break;
                }
            }
        }
 
        current_thread[0] = '\0';
        if (rtos)
            snprintf(current_thread, sizeof(current_thread), "thread:%" PRIx64 ";",
                    rtos->current_thread);
 
        sig_reply_len = snprintf(sig_reply, sizeof(sig_reply), "T%2.2x%s%s",
                signal_var, stop_reason, current_thread);
 
        gdb_connection->ctrl_c = false;
    }
 
    gdb_put_packet(connection, sig_reply, sig_reply_len);
    gdb_connection->frontend_state = TARGET_HALTED;
}
 
static void gdb_fileio_reply(struct target *target, struct connection *connection)
{
    struct gdb_connection *gdb_connection = connection->priv;
    char fileio_command[256];
    int command_len;
    bool program_exited = false;
 
    if (strcmp(target->fileio_info->identifier, "open") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64 "/%" PRIx64 ",%" PRIx64 ",%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1,
                target->fileio_info->param_2 + 1,   /* len + trailing zero */
                target->fileio_info->param_3,
                target->fileio_info->param_4);
    else if (strcmp(target->fileio_info->identifier, "close") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1);
    else if (strcmp(target->fileio_info->identifier, "read") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64 ",%" PRIx64 ",%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1,
                target->fileio_info->param_2,
                target->fileio_info->param_3);
    else if (strcmp(target->fileio_info->identifier, "write") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64 ",%" PRIx64 ",%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1,
                target->fileio_info->param_2,
                target->fileio_info->param_3);
    else if (strcmp(target->fileio_info->identifier, "lseek") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64 ",%" PRIx64 ",%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1,
                target->fileio_info->param_2,
                target->fileio_info->param_3);
    else if (strcmp(target->fileio_info->identifier, "rename") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64 "/%" PRIx64 ",%" PRIx64 "/%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1,
                target->fileio_info->param_2 + 1,   /* len + trailing zero */
                target->fileio_info->param_3,
                target->fileio_info->param_4 + 1);  /* len + trailing zero */
    else if (strcmp(target->fileio_info->identifier, "unlink") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64 "/%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1,
                target->fileio_info->param_2 + 1);  /* len + trailing zero */
    else if (strcmp(target->fileio_info->identifier, "stat") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64 "/%" PRIx64 ",%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1,
                target->fileio_info->param_2,
                target->fileio_info->param_3);
    else if (strcmp(target->fileio_info->identifier, "fstat") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64 ",%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1,
                target->fileio_info->param_2);
    else if (strcmp(target->fileio_info->identifier, "gettimeofday") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64 ",%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1,
                target->fileio_info->param_2);
    else if (strcmp(target->fileio_info->identifier, "isatty") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1);
    else if (strcmp(target->fileio_info->identifier, "system") == 0)
        sprintf(fileio_command, "F%s,%" PRIx64 "/%" PRIx64, target->fileio_info->identifier,
                target->fileio_info->param_1,
                target->fileio_info->param_2 + 1);  /* len + trailing zero */
    else if (strcmp(target->fileio_info->identifier, "exit") == 0) {
        /* If target hits exit syscall, report to GDB the program is terminated.
         * In addition, let target run its own exit syscall handler. */
        program_exited = true;
        sprintf(fileio_command, "W%02" PRIx64, target->fileio_info->param_1);
    } else {
        LOG_DEBUG("Unknown syscall: %s", target->fileio_info->identifier);
 
        /* encounter unknown syscall, continue */
        gdb_connection->frontend_state = TARGET_RUNNING;
        target_resume(target, true, 0x0, false, false);
        return;
    }
 
    command_len = strlen(fileio_command);
    gdb_put_packet(connection, fileio_command, command_len);
 
    if (program_exited) {
        /* Use target_resume() to let target run its own exit syscall handler. */
        gdb_connection->frontend_state = TARGET_RUNNING;
        target_resume(target, true, 0x0, false, false);
    } else {
        gdb_connection->frontend_state = TARGET_HALTED;
        rtos_update_threads(target);
    }
}
 
static void gdb_frontend_halted(struct target *target, struct connection *connection)
{
    struct gdb_connection *gdb_connection = connection->priv;
 
    /* In the GDB protocol when we are stepping or continuing execution,
     * we have a lingering reply. Upon receiving a halted event
     * when we have that lingering packet, we reply to the original
     * step or continue packet.
     *
     * Executing monitor commands can bring the target in and
     * out of the running state so we'll see lots of TARGET_EVENT_XXX
     * that are to be ignored.
     */
    if (gdb_connection->frontend_state == TARGET_RUNNING) {
        /* stop forwarding log packets! */
        gdb_connection->output_flag = GDB_OUTPUT_NO;
 
        /* check fileio first */
        if (target_get_gdb_fileio_info(target, target->fileio_info) == ERROR_OK)
            gdb_fileio_reply(target, connection);
        else
            gdb_signal_reply(target, connection);
    }
}
 
static int gdb_target_callback_event_handler(struct target *target,
        enum target_event event, void *priv)
{
    struct connection *connection = priv;
    struct target *gdb_target = get_available_target_from_connection(connection);
 
    if (gdb_target != target)
        return ERROR_OK;
 
    switch (event) {
        case TARGET_EVENT_GDB_HALT:
            gdb_frontend_halted(target, connection);
            break;
        case TARGET_EVENT_HALTED:
            target_call_event_callbacks(target, TARGET_EVENT_GDB_END);
            break;
        default:
            break;
    }
 
    return ERROR_OK;
}
 
static int gdb_new_connection(struct connection *connection)
{
    struct gdb_connection *gdb_connection = malloc(sizeof(struct gdb_connection));
    struct target *target;
    int retval;
    int initial_ack;
    static unsigned int next_unique_id = 1;
 
    target = get_target_from_connection(connection);
    connection->priv = gdb_connection;
    connection->cmd_ctx->current_target = target;
 
    /* initialize gdb connection information */
    gdb_connection->buf_p = gdb_connection->buffer;
    gdb_connection->buf_cnt = 0;
    gdb_connection->ctrl_c = false;
    gdb_connection->frontend_state = TARGET_HALTED;
    gdb_connection->vflash_image = NULL;
    gdb_connection->closed = false;
    gdb_connection->busy = false;
    gdb_connection->noack_mode = 0;
    gdb_connection->sync = false;
    gdb_connection->mem_write_error = false;
    gdb_connection->attached = true;
    gdb_connection->extended_protocol = false;
    gdb_connection->target_desc.tdesc = NULL;
    gdb_connection->target_desc.tdesc_length = 0;
    gdb_connection->thread_list = NULL;
    gdb_connection->output_flag = GDB_OUTPUT_NO;
    gdb_connection->unique_index = next_unique_id++;
 
    /* output goes through gdb connection */
    command_set_output_handler(connection->cmd_ctx, gdb_output, connection);
 
    /* we must remove all breakpoints registered to the target as a previous
     * GDB session could leave dangling breakpoints if e.g. communication
     * timed out.
     */
    breakpoint_remove_all(target);
    watchpoint_remove_all(target);
 
    /* Since version 3.95 (gdb-19990504), with the exclusion of 6.5~6.8, GDB
     * sends an ACK at connection with the following comment in its source code:
     * "Ack any packet which the remote side has already sent."
     * LLDB does the same since the first gdb-remote implementation.
     * Remove the initial ACK from the incoming buffer.
     */
    retval = gdb_get_char(connection, &initial_ack);
    if (retval != ERROR_OK)
        return retval;
 
    if (initial_ack != '+')
        gdb_putback_char(connection, initial_ack);
 
    target_call_event_callbacks(target, TARGET_EVENT_GDB_ATTACH);
 
    if (target->rtos) {
        /* clean previous rtos session if supported*/
        if (target->rtos->type->clean)
            target->rtos->type->clean(target);
 
        /* update threads */
        rtos_update_threads(target);
    }
 
    if (gdb_use_memory_map) {
        /* Connect must fail if the memory map can't be set up correctly.
         *
         * This will cause an auto_probe to be invoked, which is either
         * a no-op or it will fail when the target isn't ready(e.g. not halted).
         */
        for (unsigned int i = 0; i < flash_get_bank_count(); i++) {
            struct flash_bank *p;
            p = get_flash_bank_by_num_noprobe(i);
            if (p->target != target)
                continue;
            retval = get_flash_bank_by_num(i, &p);
            if (retval != ERROR_OK) {
                LOG_ERROR("Connect failed. Consider setting up a gdb-attach event for the target "
                        "to prepare target for GDB connect, or use 'gdb_memory_map disable'.");
                return retval;
            }
        }
    }
 
    log_printf_lf(all_targets->next ? LOG_LVL_INFO : LOG_LVL_DEBUG,
            __FILE__, __LINE__, __func__,
            "New GDB Connection: %d, Target %s, state: %s",
            gdb_connection->unique_index,
            target_name(target),
            target_state_name(target));
 
    if (!target_was_examined(target)) {
        LOG_TARGET_ERROR(target, "Target not examined yet, refuse gdb connection %d!",
                  gdb_connection->unique_index);
        return ERROR_TARGET_NOT_EXAMINED;
    }
    gdb_actual_connections++;
 
    if (target->state != TARGET_HALTED)
        LOG_TARGET_WARNING(target, "GDB connection %d not halted",
                    gdb_actual_connections);
 
    /* DANGER! If we fail subsequently, we must remove this handler,
     * otherwise we occasionally see crashes as the timer can invoke the
     * callback fn.
     *
     * register callback to be informed about target events */
    target_register_event_callback(gdb_target_callback_event_handler, connection);
 
    log_add_callback(gdb_log_callback, connection);
 
    return ERROR_OK;
}
 
static int gdb_connection_closed(struct connection *connection)
{
    struct target *target;
    struct gdb_connection *gdb_connection = connection->priv;
 
    target = get_target_from_connection(connection);
 
    /* we're done forwarding messages. Tear down callback before
     * cleaning up connection.
     */
    log_remove_callback(gdb_log_callback, connection);
 
    gdb_actual_connections--;
    LOG_TARGET_DEBUG(target, "{%d} GDB Close, state: %s, gdb_actual_connections=%d",
        gdb_connection->unique_index,
        target_state_name(target),
        gdb_actual_connections);
 
    /* see if an image built with vFlash commands is left */
    if (gdb_connection->vflash_image) {
        image_close(gdb_connection->vflash_image);
        free(gdb_connection->vflash_image);
        gdb_connection->vflash_image = NULL;
    }
 
    /* if this connection registered a debug-message receiver delete it */
    delete_debug_msg_receiver(connection->cmd_ctx, target);
 
    free(connection->priv);
    connection->priv = NULL;
 
    target_unregister_event_callback(gdb_target_callback_event_handler, connection);
 
    target_call_event_callbacks(target, TARGET_EVENT_GDB_END);
 
    target_call_event_callbacks(target, TARGET_EVENT_GDB_DETACH);
 
    return ERROR_OK;
}
 
static void gdb_send_error(struct connection *connection, uint8_t the_error)
{
    char err[4];
    snprintf(err, 4, "E%2.2X", the_error);
    gdb_put_packet(connection, err, 3);
}
 
static int gdb_last_signal_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct target *target = get_target_from_connection(connection);
    struct gdb_connection *gdb_con = connection->priv;
    char sig_reply[4];
    int signal_var;
 
    if (!gdb_con->attached) {
        /* if we are here we have received a kill packet
         * reply W stop reply otherwise gdb gets very unhappy */
        gdb_put_packet(connection, "W00", 3);
        return ERROR_OK;
    }
 
    signal_var = gdb_last_signal(target);
 
    snprintf(sig_reply, 4, "S%2.2x", signal_var);
    gdb_put_packet(connection, sig_reply, 3);
 
    return ERROR_OK;
}
 
static inline int gdb_reg_pos(struct target *target, int pos, int len)
{
    if (target->endianness == TARGET_LITTLE_ENDIAN)
        return pos;
    else
        return len - 1 - pos;
}
 
/* Convert register to string of bytes. NB! The # of bits in the
 * register might be non-divisible by 8(a byte), in which
 * case an entire byte is shown.
 *
 * NB! the format on the wire is the target endianness
 *
 * The format of reg->value is little endian
 *
 */
static void gdb_str_to_target(struct target *target,
        char *tstr, struct reg *reg)
{
    int i;
 
    uint8_t *buf;
    int buf_len;
    buf = reg->value;
    buf_len = DIV_ROUND_UP(reg->size, 8);
 
    for (i = 0; i < buf_len; i++) {
        int j = gdb_reg_pos(target, i, buf_len);
        tstr += sprintf(tstr, "%02x", buf[j]);
    }
}
 
/* copy over in register buffer */
static void gdb_target_to_reg(struct target *target,
        char const *tstr, int str_len, uint8_t *bin)
{
    if (str_len % 2) {
        LOG_ERROR("BUG: gdb value with uneven number of characters encountered");
        exit(-1);
    }
 
    int i;
    for (i = 0; i < str_len; i += 2) {
        unsigned int t;
        if (sscanf(tstr + i, "%02x", &t) != 1) {
            LOG_ERROR("BUG: unable to convert register value");
            exit(-1);
        }
 
        int j = gdb_reg_pos(target, i/2, str_len/2);
        bin[j] = t;
    }
}
 
/* get register value if needed and fill the buffer accordingly */
static int gdb_get_reg_value_as_str(struct target *target, char *tstr, struct reg *reg)
{
    int retval = ERROR_OK;
 
    if (!reg->valid)
        retval = reg->type->get(reg);
 
    const unsigned int len = DIV_ROUND_UP(reg->size, 8) * 2;
    switch (retval) {
        case ERROR_OK:
            gdb_str_to_target(target, tstr, reg);
            return ERROR_OK;
        case ERROR_TARGET_RESOURCE_NOT_AVAILABLE:
            memset(tstr, 'x', len);
            tstr[len] = '\0';
            return ERROR_OK;
    }
    memset(tstr, '0', len);
    tstr[len] = '\0';
    return ERROR_FAIL;
}
 
static int gdb_get_registers_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct target *target = get_target_from_connection(connection);
    struct reg **reg_list;
    int reg_list_size;
    int retval;
    int reg_packet_size = 0;
    char *reg_packet;
    char *reg_packet_p;
    int i;
 
#ifdef _DEBUG_GDB_IO_
    LOG_DEBUG("-");
#endif
 
    if ((target->rtos) && (rtos_get_gdb_reg_list(connection) == ERROR_OK))
        return ERROR_OK;
 
    retval = target_get_gdb_reg_list(target, &reg_list, &reg_list_size,
            REG_CLASS_GENERAL);
    if (retval != ERROR_OK)
        return gdb_error(connection, retval);
 
    for (i = 0; i < reg_list_size; i++) {
        if (!reg_list[i] || !reg_list[i]->exist || reg_list[i]->hidden)
            continue;
        reg_packet_size += DIV_ROUND_UP(reg_list[i]->size, 8) * 2;
    }
 
    assert(reg_packet_size > 0);
 
    reg_packet = malloc(reg_packet_size + 1); /* plus one for string termination null */
    if (!reg_packet)
        return ERROR_FAIL;
 
    reg_packet_p = reg_packet;
 
    for (i = 0; i < reg_list_size; i++) {
        if (!reg_list[i] || !reg_list[i]->exist || reg_list[i]->hidden)
            continue;
        retval = gdb_get_reg_value_as_str(target, reg_packet_p, reg_list[i]);
        if (retval != ERROR_OK && gdb_report_register_access_error) {
            LOG_DEBUG("Couldn't get register %s.", reg_list[i]->name);
            free(reg_packet);
            free(reg_list);
            return gdb_error(connection, retval);
        }
        reg_packet_p += DIV_ROUND_UP(reg_list[i]->size, 8) * 2;
    }
 
#ifdef _DEBUG_GDB_IO_
    {
        char *reg_packet_p_debug;
        reg_packet_p_debug = strndup(reg_packet, reg_packet_size);
        LOG_DEBUG("reg_packet: %s", reg_packet_p_debug);
        free(reg_packet_p_debug);
    }
#endif
 
    gdb_put_packet(connection, reg_packet, reg_packet_size);
    free(reg_packet);
 
    free(reg_list);
 
    return ERROR_OK;
}
 
static int gdb_set_registers_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct target *target = get_target_from_connection(connection);
    int i;
    struct reg **reg_list;
    int reg_list_size;
    int retval;
    char const *packet_p;
 
#ifdef _DEBUG_GDB_IO_
    LOG_DEBUG("-");
#endif
 
    /* skip command character */
    packet++;
    packet_size--;
 
    if (packet_size % 2) {
        LOG_WARNING("GDB set_registers packet with uneven characters received, dropping connection");
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    retval = target_get_gdb_reg_list(target, &reg_list, &reg_list_size,
            REG_CLASS_GENERAL);
    if (retval != ERROR_OK)
        return gdb_error(connection, retval);
 
    packet_p = packet;
    for (i = 0; i < reg_list_size; i++) {
        uint8_t *bin_buf;
        if (!reg_list[i] || !reg_list[i]->exist || reg_list[i]->hidden)
            continue;
        int chars = (DIV_ROUND_UP(reg_list[i]->size, 8) * 2);
 
        if (packet_p + chars > packet + packet_size)
            LOG_ERROR("BUG: register packet is too small for registers");
 
        bin_buf = malloc(DIV_ROUND_UP(reg_list[i]->size, 8));
        gdb_target_to_reg(target, packet_p, chars, bin_buf);
 
        retval = reg_list[i]->type->set(reg_list[i], bin_buf);
        if (retval != ERROR_OK && gdb_report_register_access_error) {
            LOG_DEBUG("Couldn't set register %s.", reg_list[i]->name);
            free(reg_list);
            free(bin_buf);
            return gdb_error(connection, retval);
        }
 
        /* advance packet pointer */
        packet_p += chars;
 
        free(bin_buf);
    }
 
    /* free struct reg *reg_list[] array allocated by get_gdb_reg_list */
    free(reg_list);
 
    gdb_put_packet(connection, "OK", 2);
 
    return ERROR_OK;
}
 
static int gdb_get_register_packet(struct connection *connection,
    char const *packet, int packet_size)
{
    struct target *target = get_target_from_connection(connection);
    char *reg_packet;
    int reg_num = strtoul(packet + 1, NULL, 16);
    struct reg **reg_list;
    int reg_list_size;
    int retval;
 
#ifdef _DEBUG_GDB_IO_
    LOG_DEBUG("-");
#endif
 
    if (target->rtos) {
        retval = rtos_get_gdb_reg(connection, reg_num);
        if (retval == ERROR_OK)
            return ERROR_OK;
        if (retval != ERROR_NOT_IMPLEMENTED)
            return gdb_error(connection, retval);
    }
 
    retval = target_get_gdb_reg_list_noread(target, &reg_list, &reg_list_size,
            REG_CLASS_ALL);
    if (retval != ERROR_OK)
        return gdb_error(connection, retval);
 
    if ((reg_list_size <= reg_num) || !reg_list[reg_num] ||
        !reg_list[reg_num]->exist || reg_list[reg_num]->hidden) {
        LOG_ERROR("gdb requested a non-existing register (reg_num=%d)", reg_num);
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    reg_packet = calloc(DIV_ROUND_UP(reg_list[reg_num]->size, 8) * 2 + 1, 1); /* plus one for string termination null */
 
    retval = gdb_get_reg_value_as_str(target, reg_packet, reg_list[reg_num]);
    if (retval != ERROR_OK && gdb_report_register_access_error) {
        LOG_DEBUG("Couldn't get register %s.", reg_list[reg_num]->name);
        free(reg_packet);
        free(reg_list);
        return gdb_error(connection, retval);
    }
 
    gdb_put_packet(connection, reg_packet, DIV_ROUND_UP(reg_list[reg_num]->size, 8) * 2);
 
    free(reg_list);
    free(reg_packet);
 
    return ERROR_OK;
}
 
static int gdb_set_register_packet(struct connection *connection,
    char const *packet, int packet_size)
{
    struct target *target = get_target_from_connection(connection);
    char *separator;
    int reg_num = strtoul(packet + 1, &separator, 16);
    struct reg **reg_list;
    int reg_list_size;
    int retval;
 
#ifdef _DEBUG_GDB_IO_
    LOG_DEBUG("-");
#endif
 
    if (*separator != '=') {
        LOG_ERROR("GDB 'set register packet', but no '=' following the register number");
        return ERROR_SERVER_REMOTE_CLOSED;
    }
    size_t chars = strlen(separator + 1);
    uint8_t *bin_buf = malloc(chars / 2);
    gdb_target_to_reg(target, separator + 1, chars, bin_buf);
 
    if ((target->rtos) &&
            (rtos_set_reg(connection, reg_num, bin_buf) == ERROR_OK)) {
        free(bin_buf);
        gdb_put_packet(connection, "OK", 2);
        return ERROR_OK;
    }
 
    retval = target_get_gdb_reg_list_noread(target, &reg_list, &reg_list_size,
            REG_CLASS_ALL);
    if (retval != ERROR_OK) {
        free(bin_buf);
        return gdb_error(connection, retval);
    }
 
    if ((reg_list_size <= reg_num) || !reg_list[reg_num] ||
        !reg_list[reg_num]->exist || reg_list[reg_num]->hidden) {
        LOG_ERROR("gdb requested a non-existing register (reg_num=%d)", reg_num);
        free(bin_buf);
        free(reg_list);
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    if (chars != (DIV_ROUND_UP(reg_list[reg_num]->size, 8) * 2)) {
        LOG_ERROR("gdb sent %zu bits for a %" PRIu32 "-bit register (%s)",
                chars * 4, reg_list[reg_num]->size, reg_list[reg_num]->name);
        free(bin_buf);
        free(reg_list);
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    gdb_target_to_reg(target, separator + 1, chars, bin_buf);
 
    retval = reg_list[reg_num]->type->set(reg_list[reg_num], bin_buf);
    if (retval != ERROR_OK && gdb_report_register_access_error) {
        LOG_DEBUG("Couldn't set register %s.", reg_list[reg_num]->name);
        free(bin_buf);
        free(reg_list);
        return gdb_error(connection, retval);
    }
 
    gdb_put_packet(connection, "OK", 2);
 
    free(bin_buf);
    free(reg_list);
 
    return ERROR_OK;
}
 
/* No attempt is made to translate the "retval" to
 * GDB speak. This has to be done at the calling
 * site as no mapping really exists.
 */
static int gdb_error(struct connection *connection, int retval)
{
    LOG_DEBUG("Reporting %i to GDB as generic error", retval);
    gdb_send_error(connection, EFAULT);
    return ERROR_OK;
}
 
static int gdb_read_memory_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct target *target = get_available_target_from_connection(connection);
    char *separator;
    uint64_t addr = 0;
    uint32_t len = 0;
 
    uint8_t *buffer;
    char *hex_buffer;
 
    int retval = ERROR_OK;
 
    /* skip command character */
    packet++;
 
    addr = strtoull(packet, &separator, 16);
 
    if (*separator != ',') {
        LOG_ERROR("incomplete read memory packet received, dropping connection");
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    len = strtoul(separator + 1, NULL, 16);
 
    if (!len) {
        LOG_WARNING("invalid read memory packet received (len == 0)");
        gdb_put_packet(connection, "", 0);
        return ERROR_OK;
    }
 
    buffer = malloc(len);
 
    LOG_DEBUG("addr: 0x%16.16" PRIx64 ", len: 0x%8.8" PRIx32, addr, len);
 
    retval = ERROR_NOT_IMPLEMENTED;
    if (target->rtos)
        retval = rtos_read_buffer(target, addr, len, buffer);
    if (retval == ERROR_NOT_IMPLEMENTED)
        retval = target_read_buffer(target, addr, len, buffer);
 
    if ((retval != ERROR_OK) && !gdb_report_data_abort) {
        /* TODO : Here we have to lie and send back all zero's lest stack traces won't work.
         * At some point this might be fixed in GDB, in which case this code can be removed.
         *
         * OpenOCD developers are acutely aware of this problem, but there is nothing
         * gained by involving the user in this problem that hopefully will get resolved
         * eventually
         *
         * http://sourceware.org/cgi-bin/gnatsweb.pl? \
         * cmd = view%20audit-trail&database = gdb&pr = 2395
         *
         * For now, the default is to fix up things to make current GDB versions work.
         * This can be overwritten using the "gdb report_data_abort <'enable'|'disable'>" command.
         */
        memset(buffer, 0, len);
        retval = ERROR_OK;
    }
 
    if (retval == ERROR_OK) {
        hex_buffer = malloc(len * 2 + 1);
 
        size_t pkt_len = hexify(hex_buffer, buffer, len, len * 2 + 1);
 
        gdb_put_packet(connection, hex_buffer, pkt_len);
 
        free(hex_buffer);
    } else
        retval = gdb_error(connection, retval);
 
    free(buffer);
 
    return retval;
}
 
static int gdb_write_memory_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct target *target = get_available_target_from_connection(connection);
    char *separator;
    uint64_t addr = 0;
    uint32_t len = 0;
 
    uint8_t *buffer;
    int retval;
 
    /* skip command character */
    packet++;
 
    addr = strtoull(packet, &separator, 16);
 
    if (*separator != ',') {
        LOG_ERROR("incomplete write memory packet received, dropping connection");
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    len = strtoul(separator + 1, &separator, 16);
 
    if (*(separator++) != ':') {
        LOG_ERROR("incomplete write memory packet received, dropping connection");
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    buffer = malloc(len);
 
    LOG_DEBUG("addr: 0x%" PRIx64 ", len: 0x%8.8" PRIx32, addr, len);
 
    if (unhexify(buffer, separator, len) != len)
        LOG_ERROR("unable to decode memory packet");
 
    retval = ERROR_NOT_IMPLEMENTED;
    if (target->rtos)
        retval = rtos_write_buffer(target, addr, len, buffer);
    if (retval == ERROR_NOT_IMPLEMENTED)
        retval = target_write_buffer(target, addr, len, buffer);
 
    if (retval == ERROR_OK)
        gdb_put_packet(connection, "OK", 2);
    else
        retval = gdb_error(connection, retval);
 
    free(buffer);
 
    return retval;
}
 
static int gdb_write_memory_binary_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct target *target = get_available_target_from_connection(connection);
    char *separator;
    uint64_t addr = 0;
    uint32_t len = 0;
 
    int retval = ERROR_OK;
    /* Packets larger than fast_limit bytes will be acknowledged instantly on
     * the assumption that we're in a download and it's important to go as fast
     * as possible. */
    uint32_t fast_limit = 8;
 
    /* skip command character */
    packet++;
 
    addr = strtoull(packet, &separator, 16);
 
    if (*separator != ',') {
        LOG_ERROR("incomplete write memory binary packet received, dropping connection");
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    len = strtoul(separator + 1, &separator, 16);
 
    if (*(separator++) != ':') {
        LOG_ERROR("incomplete write memory binary packet received, dropping connection");
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    struct gdb_connection *gdb_connection = connection->priv;
 
    if (gdb_connection->mem_write_error)
        retval = ERROR_FAIL;
 
    if (retval == ERROR_OK) {
        if (len >= fast_limit) {
            /* By replying the packet *immediately* GDB will send us a new packet
             * while we write the last one to the target.
             * We only do this for larger writes, so that users who do something like:
             * p *((int*)0xdeadbeef)=8675309
             * will get immediate feedback that that write failed.
             */
            gdb_put_packet(connection, "OK", 2);
        }
    } else {
        retval = gdb_error(connection, retval);
        /* now that we have reported the memory write error, we can clear the condition */
        gdb_connection->mem_write_error = false;
        if (retval != ERROR_OK)
            return retval;
    }
 
    if (len) {
        LOG_DEBUG("addr: 0x%" PRIx64 ", len: 0x%8.8" PRIx32, addr, len);
 
        retval = ERROR_NOT_IMPLEMENTED;
        if (target->rtos)
            retval = rtos_write_buffer(target, addr, len, (uint8_t *)separator);
        if (retval == ERROR_NOT_IMPLEMENTED)
            retval = target_write_buffer(target, addr, len, (uint8_t *)separator);
 
        if (retval != ERROR_OK)
            gdb_connection->mem_write_error = true;
    }
 
    if (len < fast_limit) {
        if (retval != ERROR_OK) {
            gdb_error(connection, retval);
            gdb_connection->mem_write_error = false;
        } else {
            gdb_put_packet(connection, "OK", 2);
        }
    }
 
    return ERROR_OK;
}
 
static int gdb_step_continue_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct target *target = get_available_target_from_connection(connection);
    bool current = false;
    uint64_t address = 0x0;
    int retval = ERROR_OK;
 
    LOG_DEBUG("-");
 
    if (packet_size > 1)
        address = strtoull(packet + 1, NULL, 16);
    else
        current = true;
 
    gdb_running_type = packet[0];
    if (packet[0] == 'c') {
        LOG_DEBUG("continue");
        /* resume at current address, don't handle breakpoints, not debugging */
        retval = target_resume(target, current, address, false, false);
    } else if (packet[0] == 's') {
        LOG_DEBUG("step");
        /* step at current or address, don't handle breakpoints */
        retval = target_step(target, current, address, false);
    }
    return retval;
}
 
static int gdb_breakpoint_watchpoint_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct target *target = get_available_target_from_connection(connection);
    int type;
    enum breakpoint_type bp_type = BKPT_SOFT /* dummy init to avoid warning */;
    enum watchpoint_rw wp_type = WPT_READ /* dummy init to avoid warning */;
    uint64_t address;
    uint32_t size;
    char *separator;
    int retval;
 
    LOG_DEBUG("[%s]", target_name(target));
 
    type = strtoul(packet + 1, &separator, 16);
 
    if (type == 0)  /* memory breakpoint */
        bp_type = BKPT_SOFT;
    else if (type == 1) /* hardware breakpoint */
        bp_type = BKPT_HARD;
    else if (type == 2) /* write watchpoint */
        wp_type = WPT_WRITE;
    else if (type == 3) /* read watchpoint */
        wp_type = WPT_READ;
    else if (type == 4) /* access watchpoint */
        wp_type = WPT_ACCESS;
    else {
        LOG_ERROR("invalid gdb watch/breakpoint type(%d), dropping connection", type);
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    if (gdb_breakpoint_override && ((bp_type == BKPT_SOFT) || (bp_type == BKPT_HARD)))
        bp_type = gdb_breakpoint_override_type;
 
    if (*separator != ',') {
        LOG_ERROR("incomplete breakpoint/watchpoint packet received, dropping connection");
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    address = strtoull(separator + 1, &separator, 16);
 
    if (*separator != ',') {
        LOG_ERROR("incomplete breakpoint/watchpoint packet received, dropping connection");
        return ERROR_SERVER_REMOTE_CLOSED;
    }
 
    size = strtoul(separator + 1, &separator, 16);
 
    switch (type) {
        case 0:
        case 1:
            if (packet[0] == 'Z') {
                struct target *bp_target = target;
                if (target->rtos && bp_type == BKPT_SOFT) {
                    bp_target = rtos_swbp_target(target, address, size, bp_type);
                    if (!bp_target) {
                        retval = ERROR_FAIL;
                        break;
                    }
                }
                retval = breakpoint_add(bp_target, address, size, bp_type);
            } else {
                assert(packet[0] == 'z');
                retval = breakpoint_remove(target, address);
            }
            break;
        case 2:
        case 3:
        case 4:
        {
            if (packet[0] == 'Z') {
                retval = watchpoint_add(target, address, size, wp_type, 0, WATCHPOINT_IGNORE_DATA_VALUE_MASK);
            } else {
                assert(packet[0] == 'z');
                retval = watchpoint_remove(target, address);
            }
            break;
        }
        default:
        {
            retval = ERROR_NOT_IMPLEMENTED;
            break;
        }
    }
 
    if (retval == ERROR_NOT_IMPLEMENTED) {
        /* Send empty reply to report that watchpoints of this type are not supported */
        return gdb_put_packet(connection, "", 0);
    }
    if (retval != ERROR_OK)
        return gdb_error(connection, retval);
    return gdb_put_packet(connection, "OK", 2);
}
 
/* print out a string and allocate more space as needed,
 * mainly used for XML at this point
 */
static __attribute__ ((format (PRINTF_ATTRIBUTE_FORMAT, 5, 6))) void xml_printf(int *retval,
        char **xml, int *pos, int *size, const char *fmt, ...)
{
    if (*retval != ERROR_OK)
        return;
    int first = 1;
 
    for (;; ) {
        if ((!*xml) || (!first)) {
            /* start by 0 to exercise all the code paths.
             * Need minimum 2 bytes to fit 1 char and 0 terminator. */
 
            *size = *size * 2 + 2;
            char *t = *xml;
            *xml = realloc(*xml, *size);
            if (!*xml) {
                free(t);
                *retval = ERROR_SERVER_REMOTE_CLOSED;
                return;
            }
        }
 
        va_list ap;
        int ret;
        va_start(ap, fmt);
        ret = vsnprintf(*xml + *pos, *size - *pos, fmt, ap);
        va_end(ap);
        if ((ret > 0) && ((ret + 1) < *size - *pos)) {
            *pos += ret;
            return;
        }
        /* there was just enough or not enough space, allocate more. */
        first = 0;
    }
}
 
static int decode_xfer_read(char const *buf, char **annex, int *ofs, unsigned int *len)
{
    /* Locate the annex. */
    const char *annex_end = strchr(buf, ':');
    if (!annex_end)
        return ERROR_FAIL;
 
    /* After the read marker and annex, qXfer looks like a
     * traditional 'm' packet. */
    char *separator;
    *ofs = strtoul(annex_end + 1, &separator, 16);
 
    if (*separator != ',')
        return ERROR_FAIL;
 
    *len = strtoul(separator + 1, NULL, 16);
 
    /* Extract the annex if needed */
    if (annex) {
        *annex = strndup(buf, annex_end - buf);
        if (!*annex)
            return ERROR_FAIL;
    }
 
    return ERROR_OK;
}
 
static int compare_bank(const void *a, const void *b)
{
    struct flash_bank *b1, *b2;
    b1 = *((struct flash_bank **)a);
    b2 = *((struct flash_bank **)b);
 
    if (b1->base == b2->base)
        return 0;
    else if (b1->base > b2->base)
        return 1;
    else
        return -1;
}
 
static int gdb_memory_map(struct connection *connection,
        char const *packet, int packet_size)
{
    /* We get away with only specifying flash here. Regions that are not
     * specified are treated as if we provided no memory map(if not we
     * could detect the holes and mark them as RAM).
     * Normally we only execute this code once, but no big deal if we
     * have to regenerate it a couple of times.
     */
 
    struct target *target = get_available_target_from_connection(connection);
    struct flash_bank *p;
    char *xml = NULL;
    int size = 0;
    int pos = 0;
    int retval = ERROR_OK;
    struct flash_bank **banks;
    int offset;
    int length;
    char *separator;
    target_addr_t ram_start = 0;
    unsigned int target_flash_banks = 0;
 
    /* skip command character */
    packet += 23;
 
    offset = strtoul(packet, &separator, 16);
    length = strtoul(separator + 1, &separator, 16);
 
    xml_printf(&retval, &xml, &pos, &size, "<memory-map>\n");
 
    /* Sort banks in ascending order.  We need to report non-flash
     * memory as ram (or rather read/write) by default for GDB, since
     * it has no concept of non-cacheable read/write memory (i/o etc).
     */
    banks = malloc(sizeof(struct flash_bank *)*flash_get_bank_count());
 
    for (unsigned int i = 0; i < flash_get_bank_count(); i++) {
        p = get_flash_bank_by_num_noprobe(i);
        if (p->target != target)
            continue;
        retval = get_flash_bank_by_num(i, &p);
        if (retval != ERROR_OK) {
            free(banks);
            gdb_error(connection, retval);
            return retval;
        }
        banks[target_flash_banks++] = p;
    }
 
    qsort(banks, target_flash_banks, sizeof(struct flash_bank *),
        compare_bank);
 
    for (unsigned int i = 0; i < target_flash_banks; i++) {
        unsigned int sector_size = 0;
        unsigned int group_len = 0;
 
        p = banks[i];
 
        if (ram_start < p->base)
            xml_printf(&retval, &xml, &pos, &size,
                "<memory type=\"ram\" start=\"" TARGET_ADDR_FMT "\" "
                "length=\"" TARGET_ADDR_FMT "\"/>\n",
                ram_start, p->base - ram_start);
 
        if (p->read_only) {
            xml_printf(&retval, &xml, &pos, &size,
                "<memory type=\"rom\" start=\"" TARGET_ADDR_FMT "\" "
                "length=\"0x%x\"/>\n",
                p->base, p->size);
        } else {
            /* Report adjacent groups of same-size sectors.  So for
             * example top boot CFI flash will list an initial region
             * with several large sectors (maybe 128KB) and several
             * smaller ones at the end (maybe 32KB).  STR7 will have
             * regions with 8KB, 32KB, and 64KB sectors; etc.
             */
            for (unsigned int j = 0; j < p->num_sectors; j++) {
                // Maybe start a new group of sectors
                if (sector_size == 0) {
                    if (p->sectors[j].offset + p->sectors[j].size > p->size) {
                        LOG_WARNING("The flash sector at offset 0x%08" PRIx32
                            " overflows the end of %s bank.",
                            p->sectors[j].offset, p->name);
                        LOG_WARNING("The rest of bank will not show in gdb memory map.");
                        break;
                    }
                    target_addr_t start;
                    start = p->base + p->sectors[j].offset;
                    xml_printf(&retval, &xml, &pos, &size,
                        "<memory type=\"flash\" "
                        "start=\"" TARGET_ADDR_FMT "\" ",
                        start);
                    sector_size = p->sectors[j].size;
                    group_len = sector_size;
                } else {
                    group_len += sector_size; /* equal to p->sectors[j].size */
                }
 
                /* Does this finish a group of sectors?
                 * If not, continue an already-started group.
                 */
                if (j < p->num_sectors - 1
                        && p->sectors[j + 1].size == sector_size
                        && p->sectors[j + 1].offset == p->sectors[j].offset + sector_size
                        && p->sectors[j + 1].offset + p->sectors[j + 1].size <= p->size)
                    continue;
 
                xml_printf(&retval, &xml, &pos, &size,
                    "length=\"0x%x\">\n"
                    "<property name=\"blocksize\">"
                    "0x%x</property>\n"
                    "</memory>\n",
                    group_len,
                    sector_size);
                sector_size = 0;
            }
        }
 
        ram_start = p->base + p->size;
    }
 
    if (ram_start != 0)
        xml_printf(&retval, &xml, &pos, &size,
            "<memory type=\"ram\" start=\"" TARGET_ADDR_FMT "\" "
            "length=\"" TARGET_ADDR_FMT "\"/>\n",
            ram_start, target_address_max(target) - ram_start + 1);
    /* ELSE a flash chip could be at the very end of the address space, in
     * which case ram_start will be precisely 0 */
 
    free(banks);
 
    xml_printf(&retval, &xml, &pos, &size, "</memory-map>\n");
 
    if (retval != ERROR_OK) {
        free(xml);
        gdb_error(connection, retval);
        return retval;
    }
 
    if (offset + length > pos)
        length = pos - offset;
 
    char *t = malloc(length + 1);
    t[0] = 'l';
    memcpy(t + 1, xml + offset, length);
    gdb_put_packet(connection, t, length + 1);
 
    free(t);
    free(xml);
    return ERROR_OK;
}
 
static const char *gdb_get_reg_type_name(enum reg_type type)
{
    switch (type) {
        case REG_TYPE_BOOL:
            return "bool";
        case REG_TYPE_INT:
            return "int";
        case REG_TYPE_INT8:
            return "int8";
        case REG_TYPE_INT16:
            return "int16";
        case REG_TYPE_INT32:
            return "int32";
        case REG_TYPE_INT64:
            return "int64";
        case REG_TYPE_INT128:
            return "int128";
        case REG_TYPE_UINT:
            return "uint";
        case REG_TYPE_UINT8:
            return "uint8";
        case REG_TYPE_UINT16:
            return "uint16";
        case REG_TYPE_UINT32:
            return "uint32";
        case REG_TYPE_UINT64:
            return "uint64";
        case REG_TYPE_UINT128:
            return "uint128";
        case REG_TYPE_CODE_PTR:
            return "code_ptr";
        case REG_TYPE_DATA_PTR:
            return "data_ptr";
        case REG_TYPE_FLOAT:
            return "float";
        case REG_TYPE_IEEE_SINGLE:
            return "ieee_single";
        case REG_TYPE_IEEE_DOUBLE:
            return "ieee_double";
        case REG_TYPE_ARCH_DEFINED:
            return "int"; /* return arbitrary string to avoid compile warning. */
    }
 
    return "int"; /* "int" as default value */
}
 
static int lookup_add_arch_defined_types(char const **arch_defined_types_list[], const char *type_id,
                    int *num_arch_defined_types)
{
    int tbl_sz = *num_arch_defined_types;
 
    if (type_id && (strcmp(type_id, ""))) {
        for (int j = 0; j < (tbl_sz + 1); j++) {
            if (!((*arch_defined_types_list)[j])) {
                (*arch_defined_types_list)[tbl_sz++] = type_id;
                *arch_defined_types_list = realloc(*arch_defined_types_list,
                                sizeof(char *) * (tbl_sz + 1));
                (*arch_defined_types_list)[tbl_sz] = NULL;
                *num_arch_defined_types = tbl_sz;
                return 1;
            } else {
                if (!strcmp((*arch_defined_types_list)[j], type_id))
                    return 0;
            }
        }
    }
 
    return -1;
}
 
static int gdb_generate_reg_type_description(struct target *target,
        char **tdesc, int *pos, int *size, struct reg_data_type *type,
        char const **arch_defined_types_list[], int *num_arch_defined_types)
{
    int retval = ERROR_OK;
 
    if (type->type_class == REG_TYPE_CLASS_VECTOR) {
        struct reg_data_type *data_type = type->reg_type_vector->type;
        if (data_type->type == REG_TYPE_ARCH_DEFINED) {
            if (lookup_add_arch_defined_types(arch_defined_types_list, data_type->id,
                            num_arch_defined_types))
                gdb_generate_reg_type_description(target, tdesc, pos, size, data_type,
                                arch_defined_types_list,
                                num_arch_defined_types);
        }
        /* <vector id="id" type="type" count="count"/> */
        xml_printf(&retval, tdesc, pos, size,
                "<vector id=\"%s\" type=\"%s\" count=\"%" PRIu32 "\"/>\n",
                type->id, type->reg_type_vector->type->id,
                type->reg_type_vector->count);
 
    } else if (type->type_class == REG_TYPE_CLASS_UNION) {
        struct reg_data_type_union_field *field;
        field = type->reg_type_union->fields;
        while (field) {
            struct reg_data_type *data_type = field->type;
            if (data_type->type == REG_TYPE_ARCH_DEFINED) {
                if (lookup_add_arch_defined_types(arch_defined_types_list, data_type->id,
                                num_arch_defined_types))
                    gdb_generate_reg_type_description(target, tdesc, pos, size, data_type,
                                    arch_defined_types_list,
                                    num_arch_defined_types);
            }
 
            field = field->next;
        }
        /* <union id="id">
         *  <field name="name" type="type"/> ...
         * </union> */
        xml_printf(&retval, tdesc, pos, size,
                "<union id=\"%s\">\n",
                type->id);
 
        field = type->reg_type_union->fields;
        while (field) {
            xml_printf(&retval, tdesc, pos, size,
                    "<field name=\"%s\" type=\"%s\"/>\n",
                    field->name, field->type->id);
 
            field = field->next;
        }
 
        xml_printf(&retval, tdesc, pos, size,
                "</union>\n");
 
    } else if (type->type_class == REG_TYPE_CLASS_STRUCT) {
        struct reg_data_type_struct_field *field;
        field = type->reg_type_struct->fields;
 
        if (field->use_bitfields) {
            /* <struct id="id" size="size">
             *  <field name="name" start="start" end="end"/> ...
             * </struct> */
            xml_printf(&retval, tdesc, pos, size,
                    "<struct id=\"%s\" size=\"%" PRIu32 "\">\n",
                    type->id, type->reg_type_struct->size);
            while (field) {
                xml_printf(&retval, tdesc, pos, size,
                        "<field name=\"%s\" start=\"%" PRIu32 "\" end=\"%" PRIu32 "\" type=\"%s\" />\n",
                        field->name, field->bitfield->start, field->bitfield->end,
                        gdb_get_reg_type_name(field->bitfield->type));
 
                field = field->next;
            }
        } else {
            while (field) {
                struct reg_data_type *data_type = field->type;
                if (data_type->type == REG_TYPE_ARCH_DEFINED) {
                    if (lookup_add_arch_defined_types(arch_defined_types_list, data_type->id,
                                    num_arch_defined_types))
                        gdb_generate_reg_type_description(target, tdesc, pos, size, data_type,
                                        arch_defined_types_list,
                                        num_arch_defined_types);
                }
            }
 
            /* <struct id="id">
             *  <field name="name" type="type"/> ...
             * </struct> */
            xml_printf(&retval, tdesc, pos, size,
                    "<struct id=\"%s\">\n",
                    type->id);
            while (field) {
                xml_printf(&retval, tdesc, pos, size,
                        "<field name=\"%s\" type=\"%s\"/>\n",
                        field->name, field->type->id);
 
                field = field->next;
            }
        }
 
        xml_printf(&retval, tdesc, pos, size,
                "</struct>\n");
 
    } else if (type->type_class == REG_TYPE_CLASS_FLAGS) {
        /* <flags id="id" size="size">
         *  <field name="name" start="start" end="end"/> ...
         * </flags> */
        xml_printf(&retval, tdesc, pos, size,
                "<flags id=\"%s\" size=\"%" PRIu32 "\">\n",
                type->id, type->reg_type_flags->size);
 
        struct reg_data_type_flags_field *field;
        field = type->reg_type_flags->fields;
        while (field) {
            xml_printf(&retval, tdesc, pos, size,
                    "<field name=\"%s\" start=\"%" PRIu32 "\" end=\"%" PRIu32 "\" type=\"%s\" />\n",
                    field->name, field->bitfield->start, field->bitfield->end,
                    gdb_get_reg_type_name(field->bitfield->type));
 
            field = field->next;
        }
 
        xml_printf(&retval, tdesc, pos, size,
                "</flags>\n");
 
    }
 
    return ERROR_OK;
}
 
/* Get a list of available target registers features. feature_list must
 * be freed by caller.
 */
static int get_reg_features_list(struct target *target, char const **feature_list[], int *feature_list_size,
        struct reg **reg_list, int reg_list_size)
{
    int tbl_sz = 0;
 
    /* Start with only one element */
    *feature_list = calloc(1, sizeof(char *));
 
    for (int i = 0; i < reg_list_size; i++) {
        if (!reg_list[i]->exist || reg_list[i]->hidden)
            continue;
 
        if (reg_list[i]->feature
            && reg_list[i]->feature->name
            && (strcmp(reg_list[i]->feature->name, ""))) {
            /* We found a feature, check if the feature is already in the
             * table. If not, allocate a new entry for the table and
             * put the new feature in it.
             */
            for (int j = 0; j < (tbl_sz + 1); j++) {
                if (!((*feature_list)[j])) {
                    (*feature_list)[tbl_sz++] = reg_list[i]->feature->name;
                    *feature_list = realloc(*feature_list, sizeof(char *) * (tbl_sz + 1));
                    (*feature_list)[tbl_sz] = NULL;
                    break;
                } else {
                    if (!strcmp((*feature_list)[j], reg_list[i]->feature->name))
                        break;
                }
            }
        }
    }
 
    if (feature_list_size)
        *feature_list_size = tbl_sz;
 
    return ERROR_OK;
}
 
/* Create a register list that's the union of all the registers of the SMP
 * group this target is in. If the target is not part of an SMP group, this
 * returns the same as target_get_gdb_reg_list_noread().
 */
static int smp_reg_list_noread(struct target *target,
        struct reg **combined_list[], int *combined_list_size,
        enum target_register_class reg_class)
{
    if (!target->smp)
        return target_get_gdb_reg_list_noread(target, combined_list,
                combined_list_size, REG_CLASS_ALL);
 
    unsigned int combined_allocated = 256;
    struct reg **local_list = malloc(combined_allocated * sizeof(struct reg *));
    if (!local_list) {
        LOG_ERROR("malloc(%zu) failed", combined_allocated * sizeof(struct reg *));
        return ERROR_FAIL;
    }
    unsigned int local_list_size = 0;
 
    struct target_list *head;
    foreach_smp_target(head, target->smp_targets) {
        if (!target_was_examined(head->target))
            continue;
 
        struct reg **reg_list = NULL;
        int reg_list_size;
        int result = target_get_gdb_reg_list_noread(head->target, &reg_list,
                &reg_list_size, reg_class);
        if (result != ERROR_OK) {
            free(local_list);
            return result;
        }
        for (int i = 0; i < reg_list_size; i++) {
            bool found = false;
            struct reg *a = reg_list[i];
            if (a->exist) {
                /* Nested loop makes this O(n^2), but this entire function with
                 * 5 RISC-V targets takes just 2ms on my computer. Fast enough
                 * for me. */
                for (unsigned int j = 0; j < local_list_size; j++) {
                    struct reg *b = local_list[j];
                    if (!strcmp(a->name, b->name)) {
                        found = true;
                        if (a->size != b->size) {
                            LOG_ERROR("SMP register %s is %d bits on one "
                                    "target, but %d bits on another target.",
                                    a->name, a->size, b->size);
                            free(reg_list);
                            free(local_list);
                            return ERROR_FAIL;
                        }
                        break;
                    }
                }
                if (!found) {
                    LOG_TARGET_DEBUG(target, "%s not found in combined list", a->name);
                    if (local_list_size >= combined_allocated) {
                        combined_allocated *= 2;
                        local_list = realloc(local_list, combined_allocated * sizeof(struct reg *));
                        if (!local_list) {
                            LOG_ERROR("realloc(%zu) failed", combined_allocated * sizeof(struct reg *));
                            free(reg_list);
                            return ERROR_FAIL;
                        }
                    }
                    local_list[local_list_size] = a;
                    local_list_size++;
                }
            }
        }
        free(reg_list);
    }
 
    if (local_list_size == 0) {
        LOG_ERROR("Unable to get register list");
        free(local_list);
        return ERROR_FAIL;
    }
 
    /* Now warn the user about any registers that weren't found in every target. */
    foreach_smp_target(head, target->smp_targets) {
        if (!target_was_examined(head->target))
            continue;
 
        struct reg **reg_list = NULL;
        int reg_list_size;
        int result = target_get_gdb_reg_list_noread(head->target, &reg_list,
                &reg_list_size, reg_class);
        if (result != ERROR_OK) {
            free(local_list);
            return result;
        }
        for (unsigned int i = 0; i < local_list_size; i++) {
            bool found = false;
            struct reg *a = local_list[i];
            for (int j = 0; j < reg_list_size; j++) {
                struct reg *b = reg_list[j];
                if (b->exist && !strcmp(a->name, b->name)) {
                    found = true;
                    break;
                }
            }
            if (!found) {
                LOG_TARGET_WARNING(head->target, "Register %s does not exist, which is part of an SMP group where "
                        "this register does exist.", a->name);
            }
        }
        free(reg_list);
    }
 
    *combined_list = local_list;
    *combined_list_size = local_list_size;
    return ERROR_OK;
}
 
static int gdb_generate_target_description(struct target *target, char **tdesc_out)
{
    int retval = ERROR_OK;
    struct reg **reg_list = NULL;
    int reg_list_size;
    char const *architecture;
    char const **features = NULL;
    int feature_list_size = 0;
    char *tdesc = NULL;
    int pos = 0;
    int size = 0;
 
 
    retval = smp_reg_list_noread(target, &reg_list, &reg_list_size,
            REG_CLASS_ALL);
 
    if (retval != ERROR_OK) {
        LOG_ERROR("get register list failed");
        retval = ERROR_FAIL;
        goto error;
    }
 
    if (reg_list_size <= 0) {
        LOG_ERROR("get register list failed");
        retval = ERROR_FAIL;
        goto error;
    }
 
    /* Get a list of available target registers features */
    retval = get_reg_features_list(target, &features, &feature_list_size, reg_list, reg_list_size);
    if (retval != ERROR_OK) {
        LOG_ERROR("Can't get the registers feature list");
        retval = ERROR_FAIL;
        goto error;
    }
 
    /* If we found some features associated with registers, create sections */
    int current_feature = 0;
 
    xml_printf(&retval, &tdesc, &pos, &size,
            "<?xml version=\"1.0\"?>\n"
            "<!DOCTYPE target SYSTEM \"gdb-target.dtd\">\n"
            "<target version=\"1.0\">\n");
 
    /* generate architecture element if supported by target */
    architecture = target_get_gdb_arch(target);
    if (architecture)
        xml_printf(&retval, &tdesc, &pos, &size,
                "<architecture>%s</architecture>\n", architecture);
 
    /* generate target description according to register list */
    if (features) {
        while (features[current_feature]) {
            char const **arch_defined_types = NULL;
            int num_arch_defined_types = 0;
 
            arch_defined_types = calloc(1, sizeof(char *));
            xml_printf(&retval, &tdesc, &pos, &size,
                    "<feature name=\"%s\">\n",
                    features[current_feature]);
 
            int i;
            for (i = 0; i < reg_list_size; i++) {
 
                if (!reg_list[i]->exist || reg_list[i]->hidden)
                    continue;
 
                if (strcmp(reg_list[i]->feature->name, features[current_feature]))
                    continue;
 
                const char *type_str;
                if (reg_list[i]->reg_data_type) {
                    if (reg_list[i]->reg_data_type->type == REG_TYPE_ARCH_DEFINED) {
                        /* generate <type... first, if there are architecture-defined types. */
                        if (lookup_add_arch_defined_types(&arch_defined_types,
                                        reg_list[i]->reg_data_type->id,
                                        &num_arch_defined_types))
                            gdb_generate_reg_type_description(target, &tdesc, &pos, &size,
                                            reg_list[i]->reg_data_type,
                                            &arch_defined_types,
                                            &num_arch_defined_types);
 
                        type_str = reg_list[i]->reg_data_type->id;
                    } else {
                        /* predefined type */
                        type_str = gdb_get_reg_type_name(
                                reg_list[i]->reg_data_type->type);
                    }
                } else {
                    /* Default type is "int" */
                    type_str = "int";
                }
 
                xml_printf(&retval, &tdesc, &pos, &size,
                        "<reg name=\"%s\"", reg_list[i]->name);
                xml_printf(&retval, &tdesc, &pos, &size,
                        " bitsize=\"%" PRIu32 "\"", reg_list[i]->size);
                xml_printf(&retval, &tdesc, &pos, &size,
                        " regnum=\"%" PRIu32 "\"", reg_list[i]->number);
                if (reg_list[i]->caller_save)
                    xml_printf(&retval, &tdesc, &pos, &size,
                            " save-restore=\"yes\"");
                else
                    xml_printf(&retval, &tdesc, &pos, &size,
                            " save-restore=\"no\"");
 
                xml_printf(&retval, &tdesc, &pos, &size,
                        " type=\"%s\"", type_str);
 
                if (reg_list[i]->group)
                    xml_printf(&retval, &tdesc, &pos, &size,
                            " group=\"%s\"", reg_list[i]->group);
 
                xml_printf(&retval, &tdesc, &pos, &size,
                        "/>\n");
            }
 
            xml_printf(&retval, &tdesc, &pos, &size,
                    "</feature>\n");
 
            current_feature++;
            free(arch_defined_types);
        }
    }
 
    xml_printf(&retval, &tdesc, &pos, &size,
            "</target>\n");
 
error:
    free(features);
    free(reg_list);
 
    if (retval == ERROR_OK)
        *tdesc_out = tdesc;
    else
        free(tdesc);
 
    return retval;
}
 
static int gdb_get_target_description_chunk(struct target *target, struct target_desc_format *target_desc,
        char **chunk, int32_t offset, uint32_t length)
{
    if (!target_desc) {
        LOG_ERROR("Unable to Generate Target Description");
        return ERROR_FAIL;
    }
 
    char *tdesc = target_desc->tdesc;
    uint32_t tdesc_length = target_desc->tdesc_length;
 
    if (!tdesc) {
        int retval = gdb_generate_target_description(target, &tdesc);
        if (retval != ERROR_OK) {
            LOG_ERROR("Unable to Generate Target Description");
            return ERROR_FAIL;
        }
 
        tdesc_length = strlen(tdesc);
    }
 
    char transfer_type;
 
    if (length < (tdesc_length - offset))
        transfer_type = 'm';
    else
        transfer_type = 'l';
 
    *chunk = malloc(length + 2);
    if (!*chunk) {
        LOG_ERROR("Unable to allocate memory");
        return ERROR_FAIL;
    }
 
    (*chunk)[0] = transfer_type;
    if (transfer_type == 'm') {
        strncpy((*chunk) + 1, tdesc + offset, length);
        (*chunk)[1 + length] = '\0';
    } else {
        strncpy((*chunk) + 1, tdesc + offset, tdesc_length - offset);
        (*chunk)[1 + (tdesc_length - offset)] = '\0';
 
        /* After gdb-server sends out last chunk, invalidate tdesc. */
        free(tdesc);
        tdesc = NULL;
        tdesc_length = 0;
    }
 
    target_desc->tdesc = tdesc;
    target_desc->tdesc_length = tdesc_length;
 
    return ERROR_OK;
}
 
static int gdb_target_description_supported(struct target *target, bool *supported)
{
    int retval = ERROR_OK;
    struct reg **reg_list = NULL;
    int reg_list_size = 0;
    char const **features = NULL;
    int feature_list_size = 0;
 
    char const *architecture = target_get_gdb_arch(target);
 
    retval = target_get_gdb_reg_list_noread(target, &reg_list,
            &reg_list_size, REG_CLASS_ALL);
    if (retval != ERROR_OK) {
        LOG_ERROR("get register list failed");
        goto error;
    }
 
    if (reg_list_size <= 0) {
        LOG_ERROR("get register list failed");
        retval = ERROR_FAIL;
        goto error;
    }
 
    /* Get a list of available target registers features */
    retval = get_reg_features_list(target, &features, &feature_list_size, reg_list, reg_list_size);
    if (retval != ERROR_OK) {
        LOG_ERROR("Can't get the registers feature list");
        goto error;
    }
 
    if (supported) {
        if (architecture || feature_list_size)
            *supported = true;
        else
            *supported = false;
    }
 
error:
    free(features);
 
    free(reg_list);
 
    return retval;
}
 
static int gdb_generate_thread_list(struct target *target, char **thread_list_out)
{
    struct rtos *rtos = target->rtos;
    int retval = ERROR_OK;
    char *thread_list = NULL;
    int pos = 0;
    int size = 0;
 
    xml_printf(&retval, &thread_list, &pos, &size,
           "<?xml version=\"1.0\"?>\n"
           "<threads>\n");
 
    if (rtos) {
        for (int i = 0; i < rtos->thread_count; i++) {
            struct thread_detail *thread_detail = &rtos->thread_details[i];
 
            if (!thread_detail->exists)
                continue;
 
            if (thread_detail->thread_name_str)
                xml_printf(&retval, &thread_list, &pos, &size,
                       "<thread id=\"%" PRIx64 "\" name=\"%s\">",
                       thread_detail->threadid,
                       thread_detail->thread_name_str);
            else
                xml_printf(&retval, &thread_list, &pos, &size,
                       "<thread id=\"%" PRIx64 "\">", thread_detail->threadid);
 
            if (thread_detail->thread_name_str)
                xml_printf(&retval, &thread_list, &pos, &size,
                       "Name: %s", thread_detail->thread_name_str);
 
            if (thread_detail->extra_info_str) {
                if (thread_detail->thread_name_str)
                    xml_printf(&retval, &thread_list, &pos, &size,
                           ", ");
                xml_printf(&retval, &thread_list, &pos, &size,
                       "%s", thread_detail->extra_info_str);
            }
 
            xml_printf(&retval, &thread_list, &pos, &size,
                   "</thread>\n");
        }
    }
 
    xml_printf(&retval, &thread_list, &pos, &size,
           "</threads>\n");
 
    if (retval == ERROR_OK)
        *thread_list_out = thread_list;
    else
        free(thread_list);
 
    return retval;
}
 
static int gdb_get_thread_list_chunk(struct target *target, char **thread_list,
        char **chunk, int32_t offset, uint32_t length)
{
    if (!*thread_list) {
        int retval = gdb_generate_thread_list(target, thread_list);
        if (retval != ERROR_OK) {
            LOG_ERROR("Unable to Generate Thread List");
            return ERROR_FAIL;
        }
    }
 
    size_t thread_list_length = strlen(*thread_list);
    char transfer_type;
 
    length = MIN(length, thread_list_length - offset);
    if (length < (thread_list_length - offset))
        transfer_type = 'm';
    else
        transfer_type = 'l';
 
    *chunk = malloc(length + 2 + 3);
    /* Allocating extra 3 bytes prevents false positive valgrind report
     * of strlen(chunk) word access:
     * Invalid read of size 4
     * Address 0x4479934 is 44 bytes inside a block of size 45 alloc'd */
    if (!*chunk) {
        LOG_ERROR("Unable to allocate memory");
        return ERROR_FAIL;
    }
 
    (*chunk)[0] = transfer_type;
    strncpy((*chunk) + 1, (*thread_list) + offset, length);
    (*chunk)[1 + length] = '\0';
 
    /* After gdb-server sends out last chunk, invalidate thread list. */
    if (transfer_type == 'l') {
        free(*thread_list);
        *thread_list = NULL;
    }
 
    return ERROR_OK;
}
 
static int gdb_query_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct command_context *cmd_ctx = connection->cmd_ctx;
    struct gdb_connection *gdb_connection = connection->priv;
    struct target *target = get_target_from_connection(connection);
 
    if (strncmp(packet, "qRcmd,", 6) == 0) {
        if (packet_size > 6) {
            Jim_Interp *interp = cmd_ctx->interp;
            char *cmd;
            cmd = malloc((packet_size - 6) / 2 + 1);
            size_t len = unhexify((uint8_t *)cmd, packet + 6, (packet_size - 6) / 2);
            cmd[len] = 0;
 
            /* We want to print all debug output to GDB connection */
            gdb_connection->output_flag = GDB_OUTPUT_ALL;
            target_call_timer_callbacks_now();
            /* some commands need to know the GDB connection, make note of current
             * GDB connection. */
            current_gdb_connection = gdb_connection;
 
            struct target *saved_target_override = cmd_ctx->current_target_override;
            cmd_ctx->current_target_override = NULL;
 
            struct command_context *old_context = Jim_GetAssocData(interp, "context");
            Jim_DeleteAssocData(interp, "context");
            int retval = Jim_SetAssocData(interp, "context", NULL, cmd_ctx);
            if (retval == JIM_OK) {
                retval = Jim_EvalObj(interp, Jim_NewStringObj(interp, cmd, -1));
                Jim_DeleteAssocData(interp, "context");
            }
            int inner_retval = Jim_SetAssocData(interp, "context", NULL, old_context);
            if (retval == JIM_OK)
                retval = inner_retval;
 
            cmd_ctx->current_target_override = saved_target_override;
 
            current_gdb_connection = NULL;
            target_call_timer_callbacks_now();
            gdb_connection->output_flag = GDB_OUTPUT_NO;
            free(cmd);
            if (retval == JIM_RETURN)
                retval = interp->returnCode;
            int lenmsg;
            const char *cretmsg = Jim_GetString(Jim_GetResult(interp), &lenmsg);
            char *retmsg;
            if (lenmsg && cretmsg[lenmsg - 1] != '\n') {
                retmsg = alloc_printf("%s\n", cretmsg);
                lenmsg++;
            } else {
                retmsg = strdup(cretmsg);
            }
            if (!retmsg)
                return ERROR_GDB_BUFFER_TOO_SMALL;
 
            if (retval == JIM_OK) {
                if (lenmsg) {
                    char *hex_buffer = malloc(lenmsg * 2 + 1);
                    if (!hex_buffer) {
                        free(retmsg);
                        return ERROR_GDB_BUFFER_TOO_SMALL;
                    }
 
                    size_t pkt_len = hexify(hex_buffer, (const uint8_t *)retmsg, lenmsg,
                                            lenmsg * 2 + 1);
                    gdb_put_packet(connection, hex_buffer, pkt_len);
                    free(hex_buffer);
                } else {
                    gdb_put_packet(connection, "OK", 2);
                }
            } else {
                if (lenmsg)
                    gdb_output_con(connection, retmsg);
                gdb_send_error(connection, retval);
            }
            free(retmsg);
            return ERROR_OK;
        }
        gdb_put_packet(connection, "OK", 2);
        return ERROR_OK;
    } else if (strncmp(packet, "qCRC:", 5) == 0) {
        if (packet_size > 5) {
            int retval;
            char gdb_reply[10];
            char *separator;
            uint32_t checksum;
            target_addr_t addr = 0;
            uint32_t len = 0;
 
            /* skip command character */
            packet += 5;
 
            addr = strtoull(packet, &separator, 16);
 
            if (*separator != ',') {
                LOG_ERROR("incomplete read memory packet received, dropping connection");
                return ERROR_SERVER_REMOTE_CLOSED;
            }
 
            len = strtoul(separator + 1, NULL, 16);
 
            gdb_connection->output_flag = GDB_OUTPUT_NOTIF;
            retval = target_checksum_memory(target, addr, len, &checksum);
            gdb_connection->output_flag = GDB_OUTPUT_NO;
 
            if (retval == ERROR_OK) {
                snprintf(gdb_reply, 10, "C%8.8" PRIx32, checksum);
                gdb_put_packet(connection, gdb_reply, 9);
            } else {
                retval = gdb_error(connection, retval);
                if (retval != ERROR_OK)
                    return retval;
            }
 
            return ERROR_OK;
        }
    } else if (strncmp(packet, "qSupported", 10) == 0) {
        /* we currently support packet size and qXfer:memory-map:read (if enabled)
         * qXfer:features:read is supported for some targets */
        int retval = ERROR_OK;
        char *buffer = NULL;
        int pos = 0;
        int size = 0;
        bool gdb_target_desc_supported = false;
 
        /* we need to test that the target supports target descriptions */
        retval = gdb_target_description_supported(target, &gdb_target_desc_supported);
        if (retval != ERROR_OK) {
            LOG_INFO("Failed detecting Target Description Support, disabling");
            gdb_target_desc_supported = false;
        }
 
        /* support may be disabled globally */
        if (!gdb_use_target_description) {
            if (gdb_target_desc_supported)
                LOG_WARNING("Target Descriptions Supported, but disabled");
            gdb_target_desc_supported = false;
        }
 
        xml_printf(&retval,
            &buffer,
            &pos,
            &size,
            "PacketSize=%x;qXfer:memory-map:read%c;qXfer:features:read%c;qXfer:threads:read+;QStartNoAckMode+;vContSupported+",
            GDB_BUFFER_SIZE,
            (gdb_use_memory_map && (flash_get_bank_count() > 0)) ? '+' : '-',
            gdb_target_desc_supported ? '+' : '-');
 
        if (retval != ERROR_OK) {
            gdb_send_error(connection, 01);
            return ERROR_OK;
        }
 
        gdb_put_packet(connection, buffer, strlen(buffer));
        free(buffer);
 
        return ERROR_OK;
    } else if ((strncmp(packet, "qXfer:memory-map:read::", 23) == 0)
           && (flash_get_bank_count() > 0))
        return gdb_memory_map(connection, packet, packet_size);
    else if (strncmp(packet, "qXfer:features:read:", 20) == 0) {
        char *xml = NULL;
        int retval = ERROR_OK;
 
        int offset;
        unsigned int length;
 
        /* skip command character */
        packet += 20;
 
        if (decode_xfer_read(packet, NULL, &offset, &length) < 0) {
            gdb_send_error(connection, 01);
            return ERROR_OK;
        }
 
        /* Target should prepare correct target description for annex.
         * The first character of returned xml is 'm' or 'l'. 'm' for
         * there are *more* chunks to transfer. 'l' for it is the *last*
         * chunk of target description.
         */
        retval = gdb_get_target_description_chunk(target, &gdb_connection->target_desc,
                &xml, offset, length);
        if (retval != ERROR_OK) {
            gdb_error(connection, retval);
            return retval;
        }
 
        gdb_put_packet(connection, xml, strlen(xml));
 
        free(xml);
        return ERROR_OK;
    } else if (strncmp(packet, "qXfer:threads:read:", 19) == 0) {
        char *xml = NULL;
        int retval = ERROR_OK;
 
        int offset;
        unsigned int length;
 
        /* skip command character */
        packet += 19;
 
        if (decode_xfer_read(packet, NULL, &offset, &length) < 0) {
            gdb_send_error(connection, 01);
            return ERROR_OK;
        }
 
        /* Target should prepare correct thread list for annex.
         * The first character of returned xml is 'm' or 'l'. 'm' for
         * there are *more* chunks to transfer. 'l' for it is the *last*
         * chunk of target description.
         */
        retval = gdb_get_thread_list_chunk(target, &gdb_connection->thread_list,
                           &xml, offset, length);
        if (retval != ERROR_OK) {
            gdb_error(connection, retval);
            return retval;
        }
 
        gdb_put_packet(connection, xml, strlen(xml));
 
        free(xml);
        return ERROR_OK;
    } else if (strncmp(packet, "QStartNoAckMode", 15) == 0) {
        gdb_connection->noack_mode = 1;
        gdb_put_packet(connection, "OK", 2);
        return ERROR_OK;
    } else if (target->type->gdb_query_custom) {
        char *buffer = NULL;
        int ret = target->type->gdb_query_custom(target, packet, &buffer);
        gdb_put_packet(connection, buffer, strlen(buffer));
        return ret;
    }
 
    gdb_put_packet(connection, "", 0);
    return ERROR_OK;
}
 
static bool gdb_handle_vcont_packet(struct connection *connection, const char *packet,
    __attribute__((unused)) int packet_size)
{
    struct gdb_connection *gdb_connection = connection->priv;
    struct target *target = get_available_target_from_connection(connection);
    const char *parse = packet;
    int retval;
 
    /* query for vCont supported */
    if (parse[0] == '?') {
        if (target->type->step) {
            /* gdb doesn't accept c without C and s without S */
            gdb_put_packet(connection, "vCont;c;C;s;S", 13);
            return true;
        }
        return false;
    }
 
    if (parse[0] == ';') {
        ++parse;
    }
 
    /* simple case, a continue packet */
    if (parse[0] == 'c') {
        gdb_running_type = 'c';
        LOG_TARGET_DEBUG(target, "target continue");
        gdb_connection->output_flag = GDB_OUTPUT_ALL;
        retval = target_resume(target, true, 0, false, false);
        if (retval == ERROR_TARGET_NOT_HALTED)
            LOG_TARGET_INFO(target, "target was not halted when resume was requested");
 
        /* poll target in an attempt to make its internal state consistent */
        if (retval != ERROR_OK) {
            retval = target_poll(target);
            if (retval != ERROR_OK)
                LOG_TARGET_DEBUG(target, "error polling target after failed resume");
        }
 
        /*
         * We don't report errors to gdb here, move frontend_state to
         * TARGET_RUNNING to stay in sync with gdb's expectation of the
         * target state
         */
        gdb_connection->frontend_state = TARGET_RUNNING;
        target_call_event_callbacks(target, TARGET_EVENT_GDB_START);
 
        return true;
    }
 
    /* single-step or step-over-breakpoint */
    if (parse[0] == 's') {
        gdb_running_type = 's';
        bool fake_step = false;
 
        struct target *ct = target;
        bool current_pc = true;
        int64_t thread_id;
        parse++;
        if (parse[0] == ':') {
            char *endp;
            parse++;
            thread_id = strtoll(parse, &endp, 16);
            if (endp) {
                parse = endp;
            }
        } else {
            thread_id = 0;
        }
 
        if (target->rtos) {
            /* Sometimes this results in picking a different thread than
             * gdb just requested to step. Then we fake it, and now there's
             * a different thread selected than gdb expects, so register
             * accesses go to the wrong one!
             * E.g.:
             * Hg1$
             * P8=72101ce197869329$     # write r8 on thread 1
             * g$
             * vCont?$
             * vCont;s:1;c$             # rtos_update_threads changes to other thread
             * g$
             * qXfer:threads:read::0,fff$
             * P8=cc060607eb89ca7f$     # write r8 on other thread
             * g$
             */
             /* rtos_update_threads(target); */
 
            target->rtos->gdb_target_for_threadid(connection, thread_id, &ct);
 
            /*
             * check if the thread to be stepped is the current rtos thread
             * if not, we must fake the step
             */
            fake_step = rtos_needs_fake_step(target, thread_id);
        }
 
        if (parse[0] == ';') {
            ++parse;
 
            if (parse[0] == 'c') {
                parse += 1;
 
                /* check if thread-id follows */
                if (parse[0] == ':') {
                    int64_t tid;
                    parse += 1;
 
                    tid = strtoll(parse, NULL, 16);
                    if (tid == thread_id) {
                        /*
                         * Special case: only step a single thread (core),
                         * keep the other threads halted. Currently, only
                         * aarch64 target understands it. Other target types don't
                         * care (nobody checks the actual value of 'current')
                         * and it doesn't really matter. This deserves
                         * a symbolic constant and a formal interface documentation
                         * at a later time.
                         */
                        LOG_DEBUG("request to step current core only");
                        /* uncomment after checking that indeed other targets are safe */
                        /*current_pc = 2;*/
                    }
                }
            }
        }
 
        LOG_TARGET_DEBUG(ct, "single-step thread %" PRIx64, thread_id);
        gdb_connection->output_flag = GDB_OUTPUT_ALL;
        target_call_event_callbacks(ct, TARGET_EVENT_GDB_START);
 
        /*
         * work around an annoying gdb behaviour: when the current thread
         * is changed in gdb, it assumes that the target can follow and also
         * make the thread current. This is an assumption that cannot hold
         * for a real target running a multi-threading OS. We just fake
         * the step to not trigger an internal error in gdb. See
         * https://sourceware.org/bugzilla/show_bug.cgi?id=22925 for details
         */
        if (fake_step) {
            int sig_reply_len;
            char sig_reply[128];
 
            LOG_DEBUG("fake step thread %"PRIx64, thread_id);
 
            sig_reply_len = snprintf(sig_reply, sizeof(sig_reply),
                                    "T05thread:%016"PRIx64";", thread_id);
 
            gdb_put_packet(connection, sig_reply, sig_reply_len);
            gdb_connection->output_flag = GDB_OUTPUT_NO;
 
            return true;
        }
 
        /* support for gdb_sync command */
        if (gdb_connection->sync) {
            gdb_connection->sync = false;
            if (ct->state == TARGET_HALTED) {
                LOG_DEBUG("stepi ignored. GDB will now fetch the register state "
                                "from the target.");
                gdb_sig_halted(connection);
                gdb_connection->output_flag = GDB_OUTPUT_NO;
            } else
                gdb_connection->frontend_state = TARGET_RUNNING;
            return true;
        }
 
        retval = target_step(ct, current_pc, 0, false);
        if (retval == ERROR_TARGET_NOT_HALTED)
            LOG_TARGET_INFO(ct, "target was not halted when step was requested");
 
        /* if step was successful send a reply back to gdb */
        if (retval == ERROR_OK) {
            retval = target_poll(ct);
            if (retval != ERROR_OK)
                LOG_TARGET_DEBUG(ct, "error polling target after successful step");
            /* send back signal information */
            gdb_signal_reply(ct, connection);
            /* stop forwarding log packets! */
            gdb_connection->output_flag = GDB_OUTPUT_NO;
        } else
            gdb_connection->frontend_state = TARGET_RUNNING;
        return true;
    }
    LOG_ERROR("Unknown vCont packet");
    return false;
}
 
static char *next_hex_encoded_field(const char **str, char sep)
{
    size_t hexlen;
    const char *hex = *str;
    if (hex[0] == '\0')
        return NULL;
 
    const char *end = strchr(hex, sep);
    if (!end)
        hexlen = strlen(hex);
    else
        hexlen = end - hex;
    *str = hex + hexlen + 1;
 
    if (hexlen % 2 != 0) {
        /* Malformed hex data */
        return NULL;
    }
 
    size_t count = hexlen / 2;
    char *decoded = malloc(count + 1);
    if (!decoded)
        return NULL;
 
    size_t converted = unhexify((void *)decoded, hex, count);
    if (converted != count) {
        free(decoded);
        return NULL;
    }
 
    decoded[count] = '\0';
    return decoded;
}
 
/* handle extended restart packet */
static void gdb_restart_inferior(struct connection *connection, const char *packet, int packet_size)
{
    struct gdb_connection *gdb_con = connection->priv;
    struct target *target = get_target_from_connection(connection);
 
    breakpoint_remove_all(target);
    watchpoint_remove_all(target);
    command_run_linef(connection->cmd_ctx, "ocd_gdb_restart %s",
            target_name(target));
    /* set connection as attached after reset */
    gdb_con->attached = true;
    /*  info rtos parts */
    gdb_thread_packet(connection, packet, packet_size);
}
 
static bool gdb_handle_vrun_packet(struct connection *connection, const char *packet, int packet_size)
{
    struct target *target = get_available_target_from_connection(connection);
    const char *parse = packet;
 
    /* Skip "vRun" */
    parse += 4;
 
    if (parse[0] != ';')
        return false;
    parse++;
 
    /* Skip first field "filename"; don't know what to do with it. */
    free(next_hex_encoded_field(&parse, ';'));
 
    char *cmdline = next_hex_encoded_field(&parse, ';');
    while (cmdline) {
        char *arg = next_hex_encoded_field(&parse, ';');
        if (!arg)
            break;
        char *new_cmdline = alloc_printf("%s %s", cmdline, arg);
        free(cmdline);
        free(arg);
        cmdline = new_cmdline;
    }
 
    if (cmdline) {
        if (target->semihosting) {
            LOG_INFO("GDB set inferior command line to '%s'", cmdline);
            free(target->semihosting->cmdline);
            target->semihosting->cmdline = cmdline;
        } else {
            LOG_INFO("GDB set inferior command line to '%s' but semihosting is unavailable", cmdline);
            free(cmdline);
        }
    }
 
    gdb_restart_inferior(connection, packet, packet_size);
    gdb_put_packet(connection, "S00", 3);
    return true;
}
 
static int gdb_v_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct gdb_connection *gdb_connection = connection->priv;
    int result;
 
    struct target *target = get_available_target_from_connection(connection);
 
    if (strncmp(packet, "vCont", 5) == 0) {
        bool handled;
 
        packet += 5;
        packet_size -= 5;
 
        handled = gdb_handle_vcont_packet(connection, packet, packet_size);
        if (!handled)
            gdb_put_packet(connection, "", 0);
 
        return ERROR_OK;
    }
 
    if (strncmp(packet, "vRun", 4) == 0) {
        bool handled;
 
        handled = gdb_handle_vrun_packet(connection, packet, packet_size);
        if (!handled)
            gdb_put_packet(connection, "", 0);
 
        return ERROR_OK;
    }
 
    /* if flash programming disabled - send a empty reply */
 
    if (!gdb_flash_program) {
        gdb_put_packet(connection, "", 0);
        return ERROR_OK;
    }
 
    if (strncmp(packet, "vFlashErase:", 12) == 0) {
        target_addr_t addr;
        unsigned long length;
 
        char const *parse = packet + 12;
        if (*parse == '\0') {
            LOG_ERROR("incomplete vFlashErase packet received, dropping connection");
            return ERROR_SERVER_REMOTE_CLOSED;
        }
 
        addr = strtoull(parse, (char **)&parse, 16);
 
        if (*(parse++) != ',' || *parse == '\0') {
            LOG_ERROR("incomplete vFlashErase packet received, dropping connection");
            return ERROR_SERVER_REMOTE_CLOSED;
        }
 
        length = strtoul(parse, (char **)&parse, 16);
 
        if (*parse != '\0') {
            LOG_ERROR("incomplete vFlashErase packet received, dropping connection");
            return ERROR_SERVER_REMOTE_CLOSED;
        }
 
        /* assume all sectors need erasing - stops any problems
         * when flash_write is called multiple times */
        flash_set_dirty();
 
        /* perform any target specific operations before the erase */
        target_call_event_callbacks(target,
            TARGET_EVENT_GDB_FLASH_ERASE_START);
 
        /* vFlashErase:addr,length messages require region start and
         * end to be "block" aligned ... if padding is ever needed,
         * GDB will have become dangerously confused.
         */
        result = flash_erase_address_range(target, false, addr,
            length);
 
        /* perform any target specific operations after the erase */
        target_call_event_callbacks(target,
            TARGET_EVENT_GDB_FLASH_ERASE_END);
 
        /* perform erase */
        if (result != ERROR_OK) {
            /* GDB doesn't evaluate the actual error number returned,
             * treat a failed erase as an I/O error
             */
            gdb_send_error(connection, EIO);
            LOG_ERROR("flash_erase returned %i", result);
        } else
            gdb_put_packet(connection, "OK", 2);
 
        return ERROR_OK;
    }
 
    if (strncmp(packet, "vFlashWrite:", 12) == 0) {
        int retval;
        target_addr_t addr;
        unsigned long length;
        char const *parse = packet + 12;
 
        if (*parse == '\0') {
            LOG_ERROR("incomplete vFlashErase packet received, dropping connection");
            return ERROR_SERVER_REMOTE_CLOSED;
        }
 
        addr = strtoull(parse, (char **)&parse, 16);
        if (*(parse++) != ':') {
            LOG_ERROR("incomplete vFlashErase packet received, dropping connection");
            return ERROR_SERVER_REMOTE_CLOSED;
        }
        length = packet_size - (parse - packet);
 
        /* create a new image if there isn't already one */
        if (!gdb_connection->vflash_image) {
            gdb_connection->vflash_image = malloc(sizeof(struct image));
            image_open(gdb_connection->vflash_image, "", "build");
        }
 
        /* create new section with content from packet buffer */
        retval = image_add_section(gdb_connection->vflash_image,
                addr, length, 0x0, (uint8_t const *)parse);
        if (retval != ERROR_OK)
            return retval;
 
        gdb_put_packet(connection, "OK", 2);
 
        return ERROR_OK;
    }
 
    if (strncmp(packet, "vFlashDone", 10) == 0) {
        uint32_t written;
 
        /* GDB command 'flash-erase' does not send a vFlashWrite,
         * so nothing to write here. */
        if (!gdb_connection->vflash_image) {
            gdb_put_packet(connection, "OK", 2);
            return ERROR_OK;
        }
 
        /* process the flashing buffer. No need to erase as GDB
         * always issues a vFlashErase first. */
        target_call_event_callbacks(target,
                TARGET_EVENT_GDB_FLASH_WRITE_START);
        result = flash_write(target, gdb_connection->vflash_image,
            &written, false);
        target_call_event_callbacks(target,
            TARGET_EVENT_GDB_FLASH_WRITE_END);
        if (result != ERROR_OK) {
            if (result == ERROR_FLASH_DST_OUT_OF_BANK)
                gdb_put_packet(connection, "E.memtype", 9);
            else
                gdb_send_error(connection, EIO);
        } else {
            LOG_DEBUG("wrote %u bytes from vFlash image to flash", (unsigned)written);
            gdb_put_packet(connection, "OK", 2);
        }
 
        image_close(gdb_connection->vflash_image);
        free(gdb_connection->vflash_image);
        gdb_connection->vflash_image = NULL;
 
        return ERROR_OK;
    }
 
    gdb_put_packet(connection, "", 0);
    return ERROR_OK;
}
 
static int gdb_detach(struct connection *connection)
{
    /*
     * Only reply "OK" to GDB
     * it will close the connection and this will trigger a call to
     * gdb_connection_closed() that will in turn trigger the event
     * TARGET_EVENT_GDB_DETACH
     */
    return gdb_put_packet(connection, "OK", 2);
}
 
/* The format of 'F' response packet is
 * Fretcode,errno,Ctrl-C flag;call-specific attachment
 */
static int gdb_fileio_response_packet(struct connection *connection,
        char const *packet, int packet_size)
{
    struct target *target = get_available_target_from_connection(connection);
    char *separator;
    char *parsing_point;
    int fileio_retcode = strtoul(packet + 1, &separator, 16);
    int fileio_errno = 0;
    bool fileio_ctrl_c = false;
    int retval;
 
    LOG_DEBUG("-");
 
    if (*separator == ',') {
        parsing_point = separator + 1;
        fileio_errno = strtoul(parsing_point, &separator, 16);
        if (*separator == ',') {
            if (*(separator + 1) == 'C') {
                /* TODO: process ctrl-c */
                fileio_ctrl_c = true;
            }
        }
    }
 
    LOG_DEBUG("File-I/O response, retcode: 0x%x, errno: 0x%x, ctrl-c: %s",
            fileio_retcode, fileio_errno, fileio_ctrl_c ? "true" : "false");
 
    retval = target_gdb_fileio_end(target, fileio_retcode, fileio_errno, fileio_ctrl_c);
    if (retval != ERROR_OK)
        return ERROR_FAIL;
 
    /* After File-I/O ends, keep continue or step */
    if (gdb_running_type == 'c')
        retval = target_resume(target, true, 0x0, false, false);
    else if (gdb_running_type == 's')
        retval = target_step(target, true, 0x0, false);
    else
        retval = ERROR_FAIL;
 
    if (retval != ERROR_OK)
        return ERROR_FAIL;
 
    return ERROR_OK;
}
 
static void gdb_log_callback(void *priv, const char *file, unsigned int line,
        const char *function, const char *string)
{
    struct connection *connection = priv;
    struct gdb_connection *gdb_con = connection->priv;
 
    if (gdb_con->output_flag != GDB_OUTPUT_ALL)
        /* No out allowed */
        return;
 
    if (gdb_con->busy) {
        /* do not reply this using the O packet */
        return;
    }
 
    gdb_output_con(connection, string);
}
 
static void gdb_sig_halted(struct connection *connection)
{
    char sig_reply[4];
    snprintf(sig_reply, 4, "T%2.2x", 2);
    gdb_put_packet(connection, sig_reply, 3);
}
 
static int gdb_input_inner(struct connection *connection)
{
    /* Do not allocate this on the stack */
    static char gdb_packet_buffer[GDB_BUFFER_SIZE + 1]; /* Extra byte for null-termination */
 
    struct target *target;
    char const *packet = gdb_packet_buffer;
    int packet_size;
    int retval;
    struct gdb_connection *gdb_con = connection->priv;
    static bool warn_use_ext;
 
    target = get_target_from_connection(connection);
 
    /* drain input buffer. If one of the packets fail, then an error
     * packet is replied, if applicable.
     *
     * This loop will terminate and the error code is returned.
     *
     * The calling fn will check if this error is something that
     * can be recovered from, or if the connection must be closed.
     *
     * If the error is recoverable, this fn is called again to
     * drain the rest of the buffer.
     */
    do {
        packet_size = GDB_BUFFER_SIZE;
        retval = gdb_get_packet(connection, gdb_packet_buffer, &packet_size);
        if (retval != ERROR_OK)
            return retval;
 
        /* terminate with zero */
        gdb_packet_buffer[packet_size] = '\0';
 
        if (packet_size > 0) {
 
            gdb_log_incoming_packet(connection, gdb_packet_buffer);
 
            retval = ERROR_OK;
            switch (packet[0]) {
                case 'T':   /* Is thread alive? */
                    gdb_thread_packet(connection, packet, packet_size);
                    break;
                case 'H':   /* Set current thread ( 'c' for step and continue,
                             * 'g' for all other operations ) */
                    gdb_thread_packet(connection, packet, packet_size);
                    break;
                case 'q':
                case 'Q':
                    retval = gdb_thread_packet(connection, packet, packet_size);
                    if (retval == GDB_THREAD_PACKET_NOT_CONSUMED)
                        retval = gdb_query_packet(connection, packet, packet_size);
                    break;
                case 'g':
                    retval = gdb_get_registers_packet(connection, packet, packet_size);
                    break;
                case 'G':
                    retval = gdb_set_registers_packet(connection, packet, packet_size);
                    break;
                case 'p':
                    retval = gdb_get_register_packet(connection, packet, packet_size);
                    break;
                case 'P':
                    retval = gdb_set_register_packet(connection, packet, packet_size);
                    break;
                case 'm':
                    gdb_con->output_flag = GDB_OUTPUT_NOTIF;
                    retval = gdb_read_memory_packet(connection, packet, packet_size);
                    gdb_con->output_flag = GDB_OUTPUT_NO;
                    break;
                case 'M':
                    gdb_con->output_flag = GDB_OUTPUT_NOTIF;
                    retval = gdb_write_memory_packet(connection, packet, packet_size);
                    gdb_con->output_flag = GDB_OUTPUT_NO;
                    break;
                case 'z':
                case 'Z':
                    retval = gdb_breakpoint_watchpoint_packet(connection, packet, packet_size);
                    break;
                case '?':
                    gdb_last_signal_packet(connection, packet, packet_size);
                    /* '?' is sent after the eventual '!' */
                    if (!warn_use_ext && !gdb_con->extended_protocol) {
                        warn_use_ext = true;
                        LOG_WARNING("Prefer GDB command \"target extended-remote :%s\" instead of \"target remote :%s\"",
                                    connection->service->port, connection->service->port);
                    }
                    break;
                case 'c':
                case 's':
                {
                    gdb_thread_packet(connection, packet, packet_size);
                    gdb_con->output_flag = GDB_OUTPUT_ALL;
 
                    if (gdb_con->mem_write_error) {
                        LOG_ERROR("Memory write failure!");
 
                        /* now that we have reported the memory write error,
                         * we can clear the condition */
                        gdb_con->mem_write_error = false;
                    }
 
                    bool nostep = false;
                    bool already_running = false;
                    if (target->state == TARGET_RUNNING) {
                        LOG_WARNING("WARNING! The target is already running. "
                                "All changes GDB did to registers will be discarded! "
                                "Waiting for target to halt.");
                        already_running = true;
                    } else if (target->state != TARGET_HALTED) {
                        LOG_WARNING("The target is not in the halted nor running stated, "
                                "stepi/continue ignored.");
                        nostep = true;
                    } else if ((packet[0] == 's') && gdb_con->sync) {
                        /* Hmm..... when you issue a continue in GDB, then a "stepi" is
                         * sent by GDB first to OpenOCD, thus defeating the check to
                         * make only the single stepping have the sync feature...
                         */
                        nostep = true;
                        LOG_DEBUG("stepi ignored. GDB will now fetch the register state "
                                "from the target.");
                    }
                    gdb_con->sync = false;
 
                    if (!already_running && nostep) {
                        /* Either the target isn't in the halted state, then we can't
                         * step/continue. This might be early setup, etc.
                         *
                         * Or we want to allow GDB to pick up a fresh set of
                         * register values without modifying the target state.
                         *
                         */
                        gdb_sig_halted(connection);
 
                        /* stop forwarding log packets! */
                        gdb_con->output_flag = GDB_OUTPUT_NO;
                    } else {
                        /* We're running/stepping, in which case we can
                         * forward log output until the target is halted
                         */
                        gdb_con->frontend_state = TARGET_RUNNING;
                        target_call_event_callbacks(target, TARGET_EVENT_GDB_START);
 
                        if (!already_running) {
                            /* Here we don't want packet processing to stop even if this fails,
                             * so we use a local variable instead of retval. */
                            retval = gdb_step_continue_packet(connection, packet, packet_size);
                            if (retval != ERROR_OK) {
                                /* we'll never receive a halted
                                 * condition... issue a false one..
                                 */
                                gdb_frontend_halted(target, connection);
                            }
                        }
                    }
                }
                break;
                case 'v':
                    retval = gdb_v_packet(connection, packet, packet_size);
                    break;
                case 'D':
                    retval = gdb_detach(connection);
                    break;
                case 'X':
                    gdb_con->output_flag = GDB_OUTPUT_NOTIF;
                    retval = gdb_write_memory_binary_packet(connection, packet, packet_size);
                    gdb_con->output_flag = GDB_OUTPUT_NO;
                    break;
                case 'k':
                    if (gdb_con->extended_protocol) {
                        gdb_con->attached = false;
                        break;
                    }
                    gdb_put_packet(connection, "OK", 2);
                    return ERROR_SERVER_REMOTE_CLOSED;
                case '!':
                    /* handle extended remote protocol */
                    gdb_con->extended_protocol = true;
                    gdb_put_packet(connection, "OK", 2);
                    break;
                case 'R':
                    /* handle extended restart packet */
                    gdb_restart_inferior(connection, packet, packet_size);
                    break;
 
                case 'j':
                    /* DEPRECATED */
                    /* packet supported only by smp target i.e cortex_a.c*/
                    /* handle smp packet replying coreid played to gbd */
                    gdb_read_smp_packet(connection, packet, packet_size);
                    break;
 
                case 'J':
                    /* DEPRECATED */
                    /* packet supported only by smp target i.e cortex_a.c */
                    /* handle smp packet setting coreid to be played at next
                     * resume to gdb */
                    gdb_write_smp_packet(connection, packet, packet_size);
                    break;
 
                case 'F':
                    /* File-I/O extension */
                    /* After gdb uses host-side syscall to complete target file
                     * I/O, gdb sends host-side syscall return value to target
                     * by 'F' packet.
                     * The format of 'F' response packet is
                     * Fretcode,errno,Ctrl-C flag;call-specific attachment
                     */
                    gdb_con->frontend_state = TARGET_RUNNING;
                    gdb_con->output_flag = GDB_OUTPUT_ALL;
                    gdb_fileio_response_packet(connection, packet, packet_size);
                    break;
 
                default:
                    /* ignore unknown packets */
                    LOG_DEBUG("ignoring 0x%2.2x packet", packet[0]);
                    gdb_put_packet(connection, "", 0);
                    break;
            }
 
            /* if a packet handler returned an error, exit input loop */
            if (retval != ERROR_OK)
                return retval;
        }
 
        if (gdb_con->ctrl_c) {
            struct target *available_target = get_available_target_from_connection(connection);
            if (available_target->state == TARGET_RUNNING) {
                struct target *t = available_target;
                if (available_target->rtos)
                    available_target->rtos->gdb_target_for_threadid(connection, target->rtos->current_threadid, &t);
                retval = target_halt(t);
                if (retval == ERROR_OK)
                    retval = target_poll(t);
                if (retval != ERROR_OK)
                    target_call_event_callbacks(target, TARGET_EVENT_GDB_HALT);
                gdb_con->ctrl_c = false;
            } else {
                LOG_TARGET_INFO(target, "Not running when halt was requested, stopping GDB. (state=%d)",
                        target->state);
                target_call_event_callbacks(target, TARGET_EVENT_GDB_HALT);
            }
        }
 
    } while (gdb_con->buf_cnt > 0);
 
    return ERROR_OK;
}
 
static int gdb_input(struct connection *connection)
{
    int retval = gdb_input_inner(connection);
    struct gdb_connection *gdb_con = connection->priv;
    if (retval == ERROR_SERVER_REMOTE_CLOSED)
        return retval;
 
    /* logging does not propagate the error, yet can set the gdb_con->closed flag */
    if (gdb_con->closed)
        return ERROR_SERVER_REMOTE_CLOSED;
 
    /* we'll recover from any other errors(e.g. temporary timeouts, etc.) */
    return ERROR_OK;
}
 
/*
 * Send custom notification packet as keep-alive during memory read/write.
 *
 * From gdb 7.0 (released 2009-10-06) an unknown notification received during
 * memory read/write would be silently dropped.
 * Before gdb 7.0 any character, with exclusion of "+-$", would be considered
 * as junk and ignored.
 * In both cases the reception will reset the timeout counter in gdb, thus
 * working as a keep-alive.
 * Check putpkt_binary() and getpkt_sane() in gdb commit
 * 74531fed1f2d662debc2c209b8b3faddceb55960
 *
 * Enable remote debug in gdb with 'set debug remote 1' to either dump the junk
 * characters in gdb pre-7.0 and the notification from gdb 7.0.
 */
static void gdb_async_notif(struct connection *connection)
{
    static unsigned char count;
    unsigned char checksum = 0;
    char buf[22];
 
    int len = sprintf(buf, "%%oocd_keepalive:%2.2x", count++);
    for (int i = 1; i < len; i++)
        checksum += buf[i];
    len += sprintf(buf + len, "#%2.2x", checksum);
 
#ifdef _DEBUG_GDB_IO_
    LOG_DEBUG("sending packet '%s'", buf);
#endif
 
    gdb_write(connection, buf, len);
}
 
static void gdb_keep_client_alive(struct connection *connection)
{
    struct gdb_connection *gdb_con = connection->priv;
 
    switch (gdb_con->output_flag) {
    case GDB_OUTPUT_NO:
        /* no need for keep-alive */
        break;
    case GDB_OUTPUT_NOTIF:
        /* send asynchronous notification */
        gdb_async_notif(connection);
        break;
    case GDB_OUTPUT_ALL:
        /* send an empty O packet */
        gdb_output_con(connection, "");
        break;
    default:
        break;
    }
}
 
static const struct service_driver gdb_service_driver = {
    .name = "gdb",
    .new_connection_during_keep_alive_handler = NULL,
    .new_connection_handler = gdb_new_connection,
    .input_handler = gdb_input,
    .connection_closed_handler = gdb_connection_closed,
    .keep_client_alive_handler = gdb_keep_client_alive,
};
 
static int gdb_target_start(struct target *target, const char *port)
{
    struct gdb_service *gdb_service = malloc(sizeof(struct gdb_service));
    if (!gdb_service) {
        LOG_ERROR("Out of memory");
        return ERROR_FAIL;
    }
 
    LOG_TARGET_INFO(target, "starting gdb server on %s", port);
 
    gdb_service->target = target;
    gdb_service->core[0] = -1;
    gdb_service->core[1] = -1;
    target->gdb_service = gdb_service;
 
    int retval = add_service(&gdb_service_driver, port,
            target->gdb_max_connections, gdb_service);
    if (retval != ERROR_OK) {
        free(gdb_service);
        return retval;
    }
 
    /* initialize all targets gdb service with the same pointer */
    struct target_list *head;
    foreach_smp_target(head, target->smp_targets) {
        struct target *curr = head->target;
        if (curr != target)
            curr->gdb_service = gdb_service;
    }
 
    return ERROR_OK;
}
 
static int gdb_target_add_one(struct target *target)
{
    /*  one gdb instance per smp list */
    if ((target->smp) && (target->gdb_service))
        return ERROR_OK;
 
    /* skip targets that cannot handle a gdb connections (e.g. mem_ap) */
    if (!target_supports_gdb_connection(target)) {
        LOG_TARGET_DEBUG(target, "skip gdb server");
        return ERROR_OK;
    }
 
    if (target->gdb_port_override) {
        if (strcmp(target->gdb_port_override, "disabled") == 0) {
            LOG_TARGET_INFO(target, "gdb port disabled");
            return ERROR_OK;
        }
        return gdb_target_start(target, target->gdb_port_override);
    }
 
    if (strcmp(gdb_port_next, "disabled") == 0) {
        LOG_TARGET_INFO(target, "gdb port disabled");
        return ERROR_OK;
    }
 
    int retval = gdb_target_start(target, gdb_port_next);
    if (retval == ERROR_OK) {
        /* save the port number so can be queried with
         * $target_name cget -gdb-port
         */
        target->gdb_port_override = strdup(gdb_port_next);
 
        long portnumber;
        /* If we can parse the port number
         * then we increment the port number for the next target.
         */
        char *end;
        portnumber = strtol(gdb_port_next, &end, 0);
        if (!*end) {
            if (parse_long(gdb_port_next, &portnumber) == ERROR_OK) {
                free(gdb_port_next);
                if (portnumber) {
                    gdb_port_next = alloc_printf("%ld", portnumber+1);
                } else {
                    /* Don't increment if gdb_port is 0, since we're just
                     * trying to allocate an unused port. */
                    gdb_port_next = strdup("0");
                }
            }
        } else if (strcmp(gdb_port_next, "pipe") == 0) {
            free(gdb_port_next);
            gdb_port_next = strdup("disabled");
        }
    }
    return retval;
}
 
int gdb_target_add_all(struct target *target)
{
    if (!target) {
        LOG_WARNING("gdb services need one or more targets defined");
        return ERROR_OK;
    }
 
    while (target) {
        int retval = gdb_target_add_one(target);
        if (retval != ERROR_OK)
            return retval;
 
        target = target->next;
    }
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_gdb_sync_command)
{
    if (CMD_ARGC != 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    if (!current_gdb_connection) {
        command_print(CMD,
            "gdb sync command can only be run from within gdb using \"monitor gdb sync\"");
        return ERROR_FAIL;
    }
 
    current_gdb_connection->sync = true;
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_gdb_port_command)
{
    int retval = CALL_COMMAND_HANDLER(server_pipe_command, &gdb_port);
    if (retval == ERROR_OK) {
        free(gdb_port_next);
        gdb_port_next = strdup(gdb_port);
    }
    return retval;
}
 
COMMAND_HANDLER(handle_gdb_memory_map_command)
{
    if (CMD_ARGC != 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    COMMAND_PARSE_ENABLE(CMD_ARGV[0], gdb_use_memory_map);
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_gdb_flash_program_command)
{
    if (CMD_ARGC != 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    COMMAND_PARSE_ENABLE(CMD_ARGV[0], gdb_flash_program);
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_gdb_report_data_abort_command)
{
    if (CMD_ARGC != 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    COMMAND_PARSE_ENABLE(CMD_ARGV[0], gdb_report_data_abort);
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_gdb_report_register_access_error)
{
    if (CMD_ARGC != 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    COMMAND_PARSE_ENABLE(CMD_ARGV[0], gdb_report_register_access_error);
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_gdb_breakpoint_override_command)
{
    if (CMD_ARGC == 0) {
        /* nothing */
    } else if (CMD_ARGC == 1) {
        gdb_breakpoint_override = 1;
        if (strcmp(CMD_ARGV[0], "hard") == 0)
            gdb_breakpoint_override_type = BKPT_HARD;
        else if (strcmp(CMD_ARGV[0], "soft") == 0)
            gdb_breakpoint_override_type = BKPT_SOFT;
        else if (strcmp(CMD_ARGV[0], "disable") == 0)
            gdb_breakpoint_override = 0;
    } else
        return ERROR_COMMAND_SYNTAX_ERROR;
    if (gdb_breakpoint_override)
        LOG_USER("force %s breakpoints",
            (gdb_breakpoint_override_type == BKPT_HARD) ? "hard" : "soft");
    else
        LOG_USER("breakpoint type is not overridden");
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_gdb_target_description_command)
{
    if (CMD_ARGC != 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    COMMAND_PARSE_ENABLE(CMD_ARGV[0], gdb_use_target_description);
    return ERROR_OK;
}
 
COMMAND_HANDLER(handle_gdb_save_tdesc_command)
{
    char *tdesc;
    uint32_t tdesc_length;
    struct target *target = get_current_target(CMD_CTX);
 
    int retval = gdb_generate_target_description(target, &tdesc);
    if (retval != ERROR_OK) {
        LOG_ERROR("Unable to Generate Target Description");
        return ERROR_FAIL;
    }
 
    tdesc_length = strlen(tdesc);
 
    struct fileio *fileio;
    size_t size_written;
 
    char *tdesc_filename = alloc_printf("%s.xml", target_type_name(target));
    if (!tdesc_filename) {
        retval = ERROR_FAIL;
        goto out;
    }
 
    retval = fileio_open(&fileio, tdesc_filename, FILEIO_WRITE, FILEIO_TEXT);
 
    if (retval != ERROR_OK) {
        LOG_ERROR("Can't open %s for writing", tdesc_filename);
        goto out;
    }
 
    retval = fileio_write(fileio, tdesc_length, tdesc, &size_written);
 
    fileio_close(fileio);
 
    if (retval != ERROR_OK)
        LOG_ERROR("Error while writing the tdesc file");
 
out:
    free(tdesc_filename);
    free(tdesc);
 
    return retval;
}
 
static const struct command_registration gdb_subcommand_handlers[] = {
    {
        .name = "sync",
        .handler = handle_gdb_sync_command,
        .mode = COMMAND_ANY,
        .help = "next stepi will return immediately allowing "
            "GDB to fetch register state without affecting "
            "target state",
        .usage = ""
    },
    {
        .name = "port",
        .handler = handle_gdb_port_command,
        .mode = COMMAND_CONFIG,
        .help = "Normally gdb listens to a TCP/IP port. Each subsequent GDB "
            "server listens for the next port number after the "
            "base port number specified. "
            "No arguments reports GDB port. \"pipe\" means listen to stdin "
            "output to stdout, an integer is base port number, \"disabled\" disables "
            "port. Any other string is are interpreted as named pipe to listen to. "
            "Output pipe is the same name as input pipe, but with 'o' appended.",
        .usage = "[port_num]",
    },
    {
        .name = "memory_map",
        .handler = handle_gdb_memory_map_command,
        .mode = COMMAND_CONFIG,
        .help = "enable or disable memory map",
        .usage = "('enable'|'disable')"
    },
    {
        .name = "flash_program",
        .handler = handle_gdb_flash_program_command,
        .mode = COMMAND_CONFIG,
        .help = "enable or disable flash program",
        .usage = "('enable'|'disable')"
    },
    {
        .name = "report_data_abort",
        .handler = handle_gdb_report_data_abort_command,
        .mode = COMMAND_CONFIG,
        .help = "enable or disable reporting data aborts",
        .usage = "('enable'|'disable')"
    },
    {
        .name = "report_register_access_error",
        .handler = handle_gdb_report_register_access_error,
        .mode = COMMAND_CONFIG,
        .help = "enable or disable reporting register access errors",
        .usage = "('enable'|'disable')"
    },
    {
        .name = "breakpoint_override",
        .handler = handle_gdb_breakpoint_override_command,
        .mode = COMMAND_ANY,
        .help = "Display or specify type of breakpoint "
            "to be used by gdb 'break' commands.",
        .usage = "('hard'|'soft'|'disable')"
    },
    {
        .name = "target_description",
        .handler = handle_gdb_target_description_command,
        .mode = COMMAND_CONFIG,
        .help = "enable or disable target description",
        .usage = "('enable'|'disable')"
    },
    {
        .name = "save_tdesc",
        .handler = handle_gdb_save_tdesc_command,
        .mode = COMMAND_EXEC,
        .help = "Save the target description file",
        .usage = "",
    },
    COMMAND_REGISTRATION_DONE
};
 
static const struct command_registration gdb_command_handlers[] = {
    {
        .name = "gdb",
        .mode = COMMAND_ANY,
        .help = "GDB commands",
        .chain = gdb_subcommand_handlers,
        .usage = "",
    },
    COMMAND_REGISTRATION_DONE
};
 
int gdb_register_commands(struct command_context *cmd_ctx)
{
    gdb_port = strdup("3333");
    gdb_port_next = strdup("3333");
    return register_commands(cmd_ctx, NULL, gdb_command_handlers);
}
 
void gdb_service_free(void)
{
    free(gdb_port);
    free(gdb_port_next);
}
 
int gdb_get_actual_connections(void)
{
    return gdb_actual_connections;
}