Archipelago » qemu

/*

 * gdb server stub

 * 

 * Copyright (c) 2003-2005 Fabrice Bellard

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#ifdef CONFIG_USER_ONLY

#include <stdlib.h>

#include <stdio.h>

#include <stdarg.h>

#include <string.h>

#include <errno.h>

#include <unistd.h>

#include "qemu.h"

#else

#include "vl.h"

#endif

#include <sys/socket.h>

#include <netinet/in.h>

#include <netinet/tcp.h>

#include <signal.h>

//#define DEBUG_GDB

enum RSState {

    RS_IDLE,

    RS_GETLINE,

    RS_CHKSUM1,

    RS_CHKSUM2,

};

/* XXX: This is not thread safe.  Do we care?  */

static int gdbserver_fd = -1;

typedef struct GDBState {

    CPUState *env; /* current CPU */

    enum RSState state; /* parsing state */

    int fd;

    char line_buf[4096];

    int line_buf_index;

    int line_csum;

#ifdef CONFIG_USER_ONLY

    int running_state;

#endif

} GDBState;

#ifdef CONFIG_USER_ONLY

/* XXX: remove this hack.  */

static GDBState gdbserver_state;

#endif

static int get_char(GDBState *s)

{

    uint8_t ch;

    int ret;

    for(;;) {

        ret = read(s->fd, &ch, 1);

        if (ret < 0) {

            if (errno != EINTR && errno != EAGAIN)

                return -1;

        } else if (ret == 0) {

            return -1;

        } else {

            break;

        }

    }

    return ch;

}

static void put_buffer(GDBState *s, const uint8_t *buf, int len)

{

    int ret;

    while (len > 0) {

        ret = write(s->fd, buf, len);

        if (ret < 0) {

            if (errno != EINTR && errno != EAGAIN)

                return;

        } else {

            buf += ret;

            len -= ret;

        }

    }

}

static inline int fromhex(int v)

{

    if (v >= '0' && v <= '9')

        return v - '0';

    else if (v >= 'A' && v <= 'F')

        return v - 'A' + 10;

    else if (v >= 'a' && v <= 'f')

        return v - 'a' + 10;

    else

        return 0;

}

static inline int tohex(int v)

{

    if (v < 10)

        return v + '0';

    else

        return v - 10 + 'a';

}

static void memtohex(char *buf, const uint8_t *mem, int len)

{

    int i, c;

    char *q;

    q = buf;

    for(i = 0; i < len; i++) {

        c = mem[i];

        *q++ = tohex(c >> 4);

        *q++ = tohex(c & 0xf);

    }

    *q = '\0';

}

static void hextomem(uint8_t *mem, const char *buf, int len)

{

    int i;

    for(i = 0; i < len; i++) {

        mem[i] = (fromhex(buf[0]) << 4) | fromhex(buf[1]);

        buf += 2;

    }

}

/* return -1 if error, 0 if OK */

static int put_packet(GDBState *s, char *buf)

{

    char buf1[3];

    int len, csum, ch, i;

#ifdef DEBUG_GDB

    printf("reply='%s'\n", buf);

#endif

    for(;;) {

        buf1[0] = '$';

        put_buffer(s, buf1, 1);

        len = strlen(buf);

        put_buffer(s, buf, len);

        csum = 0;

        for(i = 0; i < len; i++) {

            csum += buf[i];

        }

        buf1[0] = '#';

        buf1[1] = tohex((csum >> 4) & 0xf);

        buf1[2] = tohex((csum) & 0xf);

        put_buffer(s, buf1, 3);

        ch = get_char(s);

        if (ch < 0)

            return -1;

        if (ch == '+')

            break;

    }

    return 0;

}

#if defined(TARGET_I386)

static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)

{

    uint32_t *registers = (uint32_t *)mem_buf;

    int i, fpus;

    for(i = 0; i < 8; i++) {

        registers[i] = env->regs[i];

    }

    registers[8] = env->eip;

    registers[9] = env->eflags;

    registers[10] = env->segs[R_CS].selector;

    registers[11] = env->segs[R_SS].selector;

    registers[12] = env->segs[R_DS].selector;

    registers[13] = env->segs[R_ES].selector;

    registers[14] = env->segs[R_FS].selector;

    registers[15] = env->segs[R_GS].selector;

    /* XXX: convert floats */

    for(i = 0; i < 8; i++) {

        memcpy(mem_buf + 16 * 4 + i * 10, &env->fpregs[i], 10);

    }

    registers[36] = env->fpuc;

    fpus = (env->fpus & ~0x3800) | (env->fpstt & 0x7) << 11;

    registers[37] = fpus;

    registers[38] = 0; /* XXX: convert tags */

    registers[39] = 0; /* fiseg */

    registers[40] = 0; /* fioff */

    registers[41] = 0; /* foseg */

    registers[42] = 0; /* fooff */

    registers[43] = 0; /* fop */

    for(i = 0; i < 16; i++)

        tswapls(&registers[i]);

    for(i = 36; i < 44; i++)

        tswapls(&registers[i]);

    return 44 * 4;

}

static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)

{

    uint32_t *registers = (uint32_t *)mem_buf;

    int i;

    for(i = 0; i < 8; i++) {

        env->regs[i] = tswapl(registers[i]);

    }

    env->eip = tswapl(registers[8]);

    env->eflags = tswapl(registers[9]);

#if defined(CONFIG_USER_ONLY)

#define LOAD_SEG(index, sreg)\

            if (tswapl(registers[index]) != env->segs[sreg].selector)\

                cpu_x86_load_seg(env, sreg, tswapl(registers[index]));

            LOAD_SEG(10, R_CS);

            LOAD_SEG(11, R_SS);

            LOAD_SEG(12, R_DS);

            LOAD_SEG(13, R_ES);

            LOAD_SEG(14, R_FS);

            LOAD_SEG(15, R_GS);

#endif

}

#elif defined (TARGET_PPC)

static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)

{

    uint32_t *registers = (uint32_t *)mem_buf, tmp;

    int i;

    /* fill in gprs */

    for(i = 0; i < 32; i++) {

        registers[i] = tswapl(env->gpr[i]);

    }

    /* fill in fprs */

    for (i = 0; i < 32; i++) {

        registers[(i * 2) + 32] = tswapl(*((uint32_t *)&env->fpr[i]));

        registers[(i * 2) + 33] = tswapl(*((uint32_t *)&env->fpr[i] + 1));

    }

    /* nip, msr, ccr, lnk, ctr, xer, mq */

    registers[96] = tswapl(env->nip);

    registers[97] = tswapl(do_load_msr(env));

    tmp = 0;

    for (i = 0; i < 8; i++)

        tmp |= env->crf[i] << (32 - ((i + 1) * 4));

    registers[98] = tswapl(tmp);

    registers[99] = tswapl(env->lr);

    registers[100] = tswapl(env->ctr);

    registers[101] = tswapl(do_load_xer(env));

    registers[102] = 0;

    return 103 * 4;

}

static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)

{

    uint32_t *registers = (uint32_t *)mem_buf;

    int i;

    /* fill in gprs */

    for (i = 0; i < 32; i++) {

        env->gpr[i] = tswapl(registers[i]);

    }

    /* fill in fprs */

    for (i = 0; i < 32; i++) {

        *((uint32_t *)&env->fpr[i]) = tswapl(registers[(i * 2) + 32]);

        *((uint32_t *)&env->fpr[i] + 1) = tswapl(registers[(i * 2) + 33]);

    }

    /* nip, msr, ccr, lnk, ctr, xer, mq */

    env->nip = tswapl(registers[96]);

    do_store_msr(env, tswapl(registers[97]));

    registers[98] = tswapl(registers[98]);

    for (i = 0; i < 8; i++)

        env->crf[i] = (registers[98] >> (32 - ((i + 1) * 4))) & 0xF;

    env->lr = tswapl(registers[99]);

    env->ctr = tswapl(registers[100]);

    do_store_xer(env, tswapl(registers[101]));

}

#elif defined (TARGET_SPARC)

static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)

{

    target_ulong *registers = (target_ulong *)mem_buf;

    int i;

    /* fill in g0..g7 */

    for(i = 0; i < 8; i++) {

        registers[i] = tswapl(env->gregs[i]);

    }

    /* fill in register window */

    for(i = 0; i < 24; i++) {

        registers[i + 8] = tswapl(env->regwptr[i]);

    }

    /* fill in fprs */

    for (i = 0; i < 32; i++) {

        registers[i + 32] = tswapl(*((uint32_t *)&env->fpr[i]));

    }

#ifndef TARGET_SPARC64

    /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */

    registers[64] = tswapl(env->y);

    {

        target_ulong tmp;

        tmp = GET_PSR(env);

        registers[65] = tswapl(tmp);

    }

    registers[66] = tswapl(env->wim);

    registers[67] = tswapl(env->tbr);

    registers[68] = tswapl(env->pc);

    registers[69] = tswapl(env->npc);

    registers[70] = tswapl(env->fsr);

    registers[71] = 0; /* csr */

    registers[72] = 0;

    return 73 * sizeof(target_ulong);

#else

    for (i = 0; i < 32; i += 2) {

        registers[i/2 + 64] = tswapl(*((uint64_t *)&env->fpr[i]));

    }

    registers[81] = tswapl(env->pc);

    registers[82] = tswapl(env->npc);

    registers[83] = tswapl(env->tstate[env->tl]);

    registers[84] = tswapl(env->fsr);

    registers[85] = tswapl(env->fprs);

    registers[86] = tswapl(env->y);

    return 87 * sizeof(target_ulong);

#endif

}

static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)

{

    target_ulong *registers = (target_ulong *)mem_buf;

    int i;

    /* fill in g0..g7 */

    for(i = 0; i < 7; i++) {

        env->gregs[i] = tswapl(registers[i]);

    }

    /* fill in register window */

    for(i = 0; i < 24; i++) {

        env->regwptr[i] = tswapl(registers[i + 8]);

    }

    /* fill in fprs */

    for (i = 0; i < 32; i++) {

        *((uint32_t *)&env->fpr[i]) = tswapl(registers[i + 32]);

    }

#ifndef TARGET_SPARC64

    /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */

    env->y = tswapl(registers[64]);

    PUT_PSR(env, tswapl(registers[65]));

    env->wim = tswapl(registers[66]);

    env->tbr = tswapl(registers[67]);

    env->pc = tswapl(registers[68]);

    env->npc = tswapl(registers[69]);

    env->fsr = tswapl(registers[70]);

#else

    for (i = 0; i < 32; i += 2) {

        uint64_t tmp;

        tmp = tswapl(registers[i/2 + 64]) << 32;

        tmp |= tswapl(registers[i/2 + 64 + 1]);

        *((uint64_t *)&env->fpr[i]) = tmp;

    }

    env->pc = tswapl(registers[81]);

    env->npc = tswapl(registers[82]);

    env->tstate[env->tl] = tswapl(registers[83]);

    env->fsr = tswapl(registers[84]);

    env->fprs = tswapl(registers[85]);

    env->y = tswapl(registers[86]);

#endif

}

#elif defined (TARGET_ARM)

static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)

{

    int i;

    uint8_t *ptr;

    ptr = mem_buf;

    /* 16 core integer registers (4 bytes each).  */

    for (i = 0; i < 16; i++)

      {

        *(uint32_t *)ptr = tswapl(env->regs[i]);

        ptr += 4;

      }

    /* 8 FPA registers (12 bytes each), FPS (4 bytes).

       Not yet implemented.  */

    memset (ptr, 0, 8 * 12 + 4);

    ptr += 8 * 12 + 4;

    /* CPSR (4 bytes).  */

    *(uint32_t *)ptr = tswapl (cpsr_read(env));

    ptr += 4;

    return ptr - mem_buf;

}

static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)

{

    int i;

    uint8_t *ptr;

    ptr = mem_buf;

    /* Core integer registers.  */

    for (i = 0; i < 16; i++)

      {

        env->regs[i] = tswapl(*(uint32_t *)ptr);

        ptr += 4;

      }

    /* Ignore FPA regs and scr.  */

    ptr += 8 * 12 + 4;

    cpsr_write (env, tswapl(*(uint32_t *)ptr), 0xffffffff);

}

#elif defined (TARGET_MIPS)

static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)

{

    int i;

    uint8_t *ptr;

    ptr = mem_buf;

    for (i = 0; i < 32; i++)

      {

        *(uint32_t *)ptr = tswapl(env->gpr[i]);

        ptr += 4;

      }

    *(uint32_t *)ptr = tswapl(env->CP0_Status);

    ptr += 4;

    *(uint32_t *)ptr = tswapl(env->LO);

    ptr += 4;

    *(uint32_t *)ptr = tswapl(env->HI);

    ptr += 4;

    *(uint32_t *)ptr = tswapl(env->CP0_BadVAddr);

    ptr += 4;

    *(uint32_t *)ptr = tswapl(env->CP0_Cause);

    ptr += 4;

    *(uint32_t *)ptr = tswapl(env->PC);

    ptr += 4;

    /* 32 FP registers, fsr, fir, fp.  Not yet implemented.  */

    return ptr - mem_buf;

}

static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)

{

    int i;

    uint8_t *ptr;

    ptr = mem_buf;

    for (i = 0; i < 32; i++)

      {

        env->gpr[i] = tswapl(*(uint32_t *)ptr);

        ptr += 4;

      }

    env->CP0_Status = tswapl(*(uint32_t *)ptr);

    ptr += 4;

    env->LO = tswapl(*(uint32_t *)ptr);

    ptr += 4;

    env->HI = tswapl(*(uint32_t *)ptr);

    ptr += 4;

    env->CP0_BadVAddr = tswapl(*(uint32_t *)ptr);

    ptr += 4;

    env->CP0_Cause = tswapl(*(uint32_t *)ptr);

    ptr += 4;

    env->PC = tswapl(*(uint32_t *)ptr);

    ptr += 4;

}

#elif defined (TARGET_SH4)

static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)

{

  uint32_t *ptr = (uint32_t *)mem_buf;

  int i;

#define SAVE(x) *ptr++=tswapl(x)

  for (i = 0; i < 16; i++) SAVE(env->gregs[i]);

  SAVE (env->pc);

  SAVE (env->pr);

  SAVE (env->gbr);

  SAVE (env->vbr);

  SAVE (env->mach);

  SAVE (env->macl);

  SAVE (env->sr);

  SAVE (0); /* TICKS */

  SAVE (0); /* STALLS */

  SAVE (0); /* CYCLES */

  SAVE (0); /* INSTS */

  SAVE (0); /* PLR */

  return ((uint8_t *)ptr - mem_buf);

}

static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)

{

  uint32_t *ptr = (uint32_t *)mem_buf;

  int i;

#define LOAD(x) (x)=*ptr++;

  for (i = 0; i < 16; i++) LOAD(env->gregs[i]);

  LOAD (env->pc);

  LOAD (env->pr);

  LOAD (env->gbr);

  LOAD (env->vbr);

  LOAD (env->mach);

  LOAD (env->macl);

  LOAD (env->sr);

}

#else

static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)

{

    return 0;

}

static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)

{

}

#endif

static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)

{

    const char *p;

    int ch, reg_size, type;

    char buf[4096];

    uint8_t mem_buf[2000];

    uint32_t *registers;

    uint32_t addr, len;

#ifdef DEBUG_GDB

    printf("command='%s'\n", line_buf);

#endif

    p = line_buf;

    ch = *p++;

    switch(ch) {

    case '?':

        /* TODO: Make this return the correct value for user-mode.  */

        snprintf(buf, sizeof(buf), "S%02x", SIGTRAP);

        put_packet(s, buf);

        break;

    case 'c':

        if (*p != '\0') {

            addr = strtoul(p, (char **)&p, 16);

#if defined(TARGET_I386)

            env->eip = addr;

#elif defined (TARGET_PPC)

            env->nip = addr;

#elif defined (TARGET_SPARC)

            env->pc = addr;

            env->npc = addr + 4;

#elif defined (TARGET_ARM)

            env->regs[15] = addr;

#elif defined (TARGET_SH4)

            env->pc = addr;

#endif

        }

#ifdef CONFIG_USER_ONLY

        s->running_state = 1;

#else

        vm_start();

#endif

        return RS_IDLE;

    case 's':

        if (*p != '\0') {

            addr = strtoul(p, (char **)&p, 16);

#if defined(TARGET_I386)

            env->eip = addr;

#elif defined (TARGET_PPC)

            env->nip = addr;

#elif defined (TARGET_SPARC)

            env->pc = addr;

            env->npc = addr + 4;

#elif defined (TARGET_ARM)

            env->regs[15] = addr;

#elif defined (TARGET_SH4)

            env->pc = addr;

#endif

        }

        cpu_single_step(env, 1);

#ifdef CONFIG_USER_ONLY

        s->running_state = 1;

#else

        vm_start();

#endif

        return RS_IDLE;

    case 'g':

        reg_size = cpu_gdb_read_registers(env, mem_buf);

        memtohex(buf, mem_buf, reg_size);

        put_packet(s, buf);

        break;

    case 'G':

        registers = (void *)mem_buf;

        len = strlen(p) / 2;

        hextomem((uint8_t *)registers, p, len);

        cpu_gdb_write_registers(env, mem_buf, len);

        put_packet(s, "OK");

        break;

    case 'm':

        addr = strtoul(p, (char **)&p, 16);

        if (*p == ',')

            p++;

        len = strtoul(p, NULL, 16);

        if (cpu_memory_rw_debug(env, addr, mem_buf, len, 0) != 0) {

            put_packet (s, "E14");

        } else {

            memtohex(buf, mem_buf, len);

            put_packet(s, buf);

        }

        break;

    case 'M':

        addr = strtoul(p, (char **)&p, 16);

        if (*p == ',')

            p++;

        len = strtoul(p, (char **)&p, 16);

        if (*p == ':')

            p++;

        hextomem(mem_buf, p, len);

        if (cpu_memory_rw_debug(env, addr, mem_buf, len, 1) != 0)

            put_packet(s, "E14");

        else

            put_packet(s, "OK");

        break;

    case 'Z':

        type = strtoul(p, (char **)&p, 16);

        if (*p == ',')

            p++;

        addr = strtoul(p, (char **)&p, 16);

        if (*p == ',')

            p++;

        len = strtoul(p, (char **)&p, 16);

        if (type == 0 || type == 1) {

            if (cpu_breakpoint_insert(env, addr) < 0)

                goto breakpoint_error;

            put_packet(s, "OK");

        } else {

        breakpoint_error:

            put_packet(s, "E22");

        }

        break;

    case 'z':

        type = strtoul(p, (char **)&p, 16);

        if (*p == ',')

            p++;

        addr = strtoul(p, (char **)&p, 16);

        if (*p == ',')

            p++;

        len = strtoul(p, (char **)&p, 16);

        if (type == 0 || type == 1) {

            cpu_breakpoint_remove(env, addr);

            put_packet(s, "OK");

        } else {

            goto breakpoint_error;

        }

        break;

    default:

        //        unknown_command:

        /* put empty packet */

        buf[0] = '\0';

        put_packet(s, buf);

        break;

    }

    return RS_IDLE;

}

extern void tb_flush(CPUState *env);

#ifndef CONFIG_USER_ONLY

static void gdb_vm_stopped(void *opaque, int reason)

{

    GDBState *s = opaque;

    char buf[256];

    int ret;

    /* disable single step if it was enable */

    cpu_single_step(s->env, 0);

    if (reason == EXCP_DEBUG) {

        tb_flush(s->env);

        ret = SIGTRAP;

    } else if (reason == EXCP_INTERRUPT) {

        ret = SIGINT;

    } else {

        ret = 0;

    }

    snprintf(buf, sizeof(buf), "S%02x", ret);

    put_packet(s, buf);

}

#endif

static void gdb_read_byte(GDBState *s, int ch)

{

    CPUState *env = s->env;

    int i, csum;

    char reply[1];

#ifndef CONFIG_USER_ONLY

    if (vm_running) {

        /* when the CPU is running, we cannot do anything except stop

           it when receiving a char */

        vm_stop(EXCP_INTERRUPT);

    } else 

#endif

    {

        switch(s->state) {

        case RS_IDLE:

            if (ch == '$') {

                s->line_buf_index = 0;

                s->state = RS_GETLINE;

            }

            break;

        case RS_GETLINE:

            if (ch == '#') {

            s->state = RS_CHKSUM1;

            } else if (s->line_buf_index >= sizeof(s->line_buf) - 1) {

                s->state = RS_IDLE;

            } else {

            s->line_buf[s->line_buf_index++] = ch;

            }

            break;

        case RS_CHKSUM1:

            s->line_buf[s->line_buf_index] = '\0';

            s->line_csum = fromhex(ch) << 4;

            s->state = RS_CHKSUM2;

            break;

        case RS_CHKSUM2:

            s->line_csum |= fromhex(ch);

            csum = 0;

            for(i = 0; i < s->line_buf_index; i++) {

                csum += s->line_buf[i];

            }

            if (s->line_csum != (csum & 0xff)) {

                reply[0] = '-';

                put_buffer(s, reply, 1);

                s->state = RS_IDLE;

            } else {

                reply[0] = '+';

                put_buffer(s, reply, 1);

                s->state = gdb_handle_packet(s, env, s->line_buf);

            }

            break;

        }

    }

}

#ifdef CONFIG_USER_ONLY

int

gdb_handlesig (CPUState *env, int sig)

{

  GDBState *s;

  char buf[256];

  int n;

  if (gdbserver_fd < 0)

    return sig;

  s = &gdbserver_state;

  /* disable single step if it was enabled */

  cpu_single_step(env, 0);

  tb_flush(env);

  if (sig != 0)

    {

      snprintf(buf, sizeof(buf), "S%02x", sig);

      put_packet(s, buf);

    }

  sig = 0;

  s->state = RS_IDLE;

  s->running_state = 0;

  while (s->running_state == 0) {

      n = read (s->fd, buf, 256);

      if (n > 0)

        {

          int i;

          for (i = 0; i < n; i++)

            gdb_read_byte (s, buf[i]);

        }

      else if (n == 0 || errno != EAGAIN)

        {

          /* XXX: Connection closed.  Should probably wait for annother

             connection before continuing.  */

          return sig;

        }

  }

  return sig;

}

/* Tell the remote gdb that the process has exited.  */

void gdb_exit(CPUState *env, int code)

{

  GDBState *s;

  char buf[4];

  if (gdbserver_fd < 0)

    return;

  s = &gdbserver_state;

  snprintf(buf, sizeof(buf), "W%02x", code);

  put_packet(s, buf);

}

#else

static void gdb_read(void *opaque)

{

    GDBState *s = opaque;

    int i, size;

    uint8_t buf[4096];

    size = read(s->fd, buf, sizeof(buf));

    if (size < 0)

        return;

    if (size == 0) {

        /* end of connection */

        qemu_del_vm_stop_handler(gdb_vm_stopped, s);

        qemu_set_fd_handler(s->fd, NULL, NULL, NULL);

        qemu_free(s);

        vm_start();

    } else {

        for(i = 0; i < size; i++)

            gdb_read_byte(s, buf[i]);

    }

}

#endif

static void gdb_accept(void *opaque)

{

    GDBState *s;

    struct sockaddr_in sockaddr;

    socklen_t len;

    int val, fd;

    for(;;) {

        len = sizeof(sockaddr);

        fd = accept(gdbserver_fd, (struct sockaddr *)&sockaddr, &len);

        if (fd < 0 && errno != EINTR) {

            perror("accept");

            return;

        } else if (fd >= 0) {

            break;

        }

    }

    /* set short latency */

    val = 1;

    setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val));

#ifdef CONFIG_USER_ONLY

    s = &gdbserver_state;

    memset (s, 0, sizeof (GDBState));

#else

    s = qemu_mallocz(sizeof(GDBState));

    if (!s) {

        close(fd);

        return;

    }

#endif

    s->env = first_cpu; /* XXX: allow to change CPU */

    s->fd = fd;

    fcntl(fd, F_SETFL, O_NONBLOCK);

#ifndef CONFIG_USER_ONLY

    /* stop the VM */

    vm_stop(EXCP_INTERRUPT);

    /* start handling I/O */

    qemu_set_fd_handler(s->fd, gdb_read, NULL, s);

    /* when the VM is stopped, the following callback is called */

    qemu_add_vm_stop_handler(gdb_vm_stopped, s);

#endif

}

static int gdbserver_open(int port)

{

    struct sockaddr_in sockaddr;

    int fd, val, ret;

    fd = socket(PF_INET, SOCK_STREAM, 0);

    if (fd < 0) {

        perror("socket");

        return -1;

    }

    /* allow fast reuse */

    val = 1;

    setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));

    sockaddr.sin_family = AF_INET;

    sockaddr.sin_port = htons(port);

    sockaddr.sin_addr.s_addr = 0;

    ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));

    if (ret < 0) {

        perror("bind");

        return -1;

    }

    ret = listen(fd, 0);

    if (ret < 0) {

        perror("listen");

        return -1;

    }

#ifndef CONFIG_USER_ONLY

    fcntl(fd, F_SETFL, O_NONBLOCK);

#endif

    return fd;

}

int gdbserver_start(int port)

{

    gdbserver_fd = gdbserver_open(port);

    if (gdbserver_fd < 0)

        return -1;

    /* accept connections */

#ifdef CONFIG_USER_ONLY

    gdb_accept (NULL);

#else

    qemu_set_fd_handler(gdbserver_fd, gdb_accept, NULL, NULL);

#endif

    return 0;

}