gdbstub.c

qemu虚拟机代码

    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;
}