remote-utils.c

这个是LINUX下的GDB调度工具的源码

  sigset_t sigio_set;
  sigemptyset (&sigio_set);
  sigaddset (&sigio_set, SIGIO);
  sigprocmask (SIG_UNBLOCK, &sigio_set, NULL);
}

/* Asynchronous I/O support.  SIGIO must be enabled when waiting, in order to
   accept Control-C from the client, and must be disabled when talking to
   the client.  */

/* Current state of asynchronous I/O.  */
static int async_io_enabled;

/* Enable asynchronous I/O.  */
void
enable_async_io (void)
{
  if (async_io_enabled)
    return;

  signal (SIGIO, input_interrupt);
  async_io_enabled = 1;
}

/* Disable asynchronous I/O.  */
void
disable_async_io (void)
{
  if (!async_io_enabled)
    return;

  signal (SIGIO, SIG_IGN);
  async_io_enabled = 0;
}

/* Returns next char from remote GDB.  -1 if error.  */

static int
readchar (void)
{
  static char buf[BUFSIZ];
  static int bufcnt = 0;
  static char *bufp;

  if (bufcnt-- > 0)
    return *bufp++ & 0x7f;

  bufcnt = read (remote_desc, buf, sizeof (buf));

  if (bufcnt <= 0)
    {
      if (bufcnt == 0)
	fprintf (stderr, "readchar: Got EOF\n");
      else
	perror ("readchar");

      return -1;
    }

  bufp = buf;
  bufcnt--;
  return *bufp++ & 0x7f;
}

/* Read a packet from the remote machine, with error checking,
   and store it in BUF.  Returns length of packet, or negative if error. */

int
getpkt (char *buf)
{
  char *bp;
  unsigned char csum, c1, c2;
  int c;

  while (1)
    {
      csum = 0;

      while (1)
	{
	  c = readchar ();
	  if (c == '$')
	    break;
	  if (remote_debug)
	    {
	      fprintf (stderr, "[getpkt: discarding char '%c']\n", c);
	      fflush (stderr);
	    }

	  if (c < 0)
	    return -1;
	}

      bp = buf;
      while (1)
	{
	  c = readchar ();
	  if (c < 0)
	    return -1;
	  if (c == '#')
	    break;
	  *bp++ = c;
	  csum += c;
	}
      *bp = 0;

      c1 = fromhex (readchar ());
      c2 = fromhex (readchar ());

      if (csum == (c1 << 4) + c2)
	break;

      fprintf (stderr, "Bad checksum, sentsum=0x%x, csum=0x%x, buf=%s\n",
	       (c1 << 4) + c2, csum, buf);
      write (remote_desc, "-", 1);
    }

  if (remote_debug)
    {
      fprintf (stderr, "getpkt (\"%s\");  [sending ack] \n", buf);
      fflush (stderr);
    }

  write (remote_desc, "+", 1);

  if (remote_debug)
    {
      fprintf (stderr, "[sent ack]\n");
      fflush (stderr);
    }

  return bp - buf;
}

void
write_ok (char *buf)
{
  buf[0] = 'O';
  buf[1] = 'K';
  buf[2] = '\0';
}

void
write_enn (char *buf)
{
  /* Some day, we should define the meanings of the error codes... */
  buf[0] = 'E';
  buf[1] = '0';
  buf[2] = '1';
  buf[3] = '\0';
}

void
convert_int_to_ascii (char *from, char *to, int n)
{
  int nib;
  char ch;
  while (n--)
    {
      ch = *from++;
      nib = ((ch & 0xf0) >> 4) & 0x0f;
      *to++ = tohex (nib);
      nib = ch & 0x0f;
      *to++ = tohex (nib);
    }
  *to++ = 0;
}


void
convert_ascii_to_int (char *from, char *to, int n)
{
  int nib1, nib2;
  while (n--)
    {
      nib1 = fromhex (*from++);
      nib2 = fromhex (*from++);
      *to++ = (((nib1 & 0x0f) << 4) & 0xf0) | (nib2 & 0x0f);
    }
}

static char *
outreg (int regno, char *buf)
{
  if ((regno >> 12) != 0)
    *buf++ = tohex ((regno >> 12) & 0xf);
  if ((regno >> 8) != 0)
    *buf++ = tohex ((regno >> 8) & 0xf);
  *buf++ = tohex ((regno >> 4) & 0xf);
  *buf++ = tohex (regno & 0xf);
  *buf++ = ':';
  collect_register_as_string (regno, buf);
  buf += 2 * register_size (regno);
  *buf++ = ';';

  return buf;
}

void
new_thread_notify (int id)
{
  char own_buf[256];

  /* The `n' response is not yet part of the remote protocol.  Do nothing.  */
  if (1)
    return;

  if (server_waiting == 0)
    return;

  sprintf (own_buf, "n%x", id);
  disable_async_io ();
  putpkt (own_buf);
  enable_async_io ();
}

void
dead_thread_notify (int id)
{
  char own_buf[256];

  /* The `x' response is not yet part of the remote protocol.  Do nothing.  */
  if (1)
    return;

  sprintf (own_buf, "x%x", id);
  disable_async_io ();
  putpkt (own_buf);
  enable_async_io ();
}

void
prepare_resume_reply (char *buf, char status, unsigned char signo)
{
  int nib, sig;

  *buf++ = status;

  sig = (int)target_signal_from_host (signo);

  nib = ((sig & 0xf0) >> 4);
  *buf++ = tohex (nib);
  nib = sig & 0x0f;
  *buf++ = tohex (nib);

  if (status == 'T')
    {
      const char **regp = gdbserver_expedite_regs;
      while (*regp)
	{
	  buf = outreg (find_regno (*regp), buf);
	  regp ++;
	}

      /* Formerly, if the debugger had not used any thread features we would not
	 burden it with a thread status response.  This was for the benefit of
	 GDB 4.13 and older.  However, in recent GDB versions the check
	 (``if (cont_thread != 0)'') does not have the desired effect because of
	 sillyness in the way that the remote protocol handles specifying a thread.
	 Since thread support relies on qSymbol support anyway, assume GDB can handle
	 threads.  */

      if (using_threads)
	{
	  /* FIXME right place to set this? */
	  thread_from_wait = ((struct inferior_list_entry *)current_inferior)->id;
	  if (debug_threads)
	    fprintf (stderr, "Writing resume reply for %d\n\n", thread_from_wait);
	  /* This if (1) ought to be unnecessary.  But remote_wait in GDB
	     will claim this event belongs to inferior_ptid if we do not
	     specify a thread, and there's no way for gdbserver to know
	     what inferior_ptid is.  */
	  if (1 || old_thread_from_wait != thread_from_wait)
	    {
	      general_thread = thread_from_wait;
	      sprintf (buf, "thread:%x;", thread_from_wait);
	      buf += strlen (buf);
	      old_thread_from_wait = thread_from_wait;
	    }
	}
    }
  /* For W and X, we're done.  */
  *buf++ = 0;
}

void
decode_m_packet (char *from, CORE_ADDR *mem_addr_ptr, unsigned int *len_ptr)
{
  int i = 0, j = 0;
  char ch;
  *mem_addr_ptr = *len_ptr = 0;

  while ((ch = from[i++]) != ',')
    {
      *mem_addr_ptr = *mem_addr_ptr << 4;
      *mem_addr_ptr |= fromhex (ch) & 0x0f;
    }

  for (j = 0; j < 4; j++)
    {
      if ((ch = from[i++]) == 0)
	break;
      *len_ptr = *len_ptr << 4;
      *len_ptr |= fromhex (ch) & 0x0f;
    }
}

void
decode_M_packet (char *from, CORE_ADDR *mem_addr_ptr, unsigned int *len_ptr,
		 char *to)
{
  int i = 0;
  char ch;
  *mem_addr_ptr = *len_ptr = 0;

  while ((ch = from[i++]) != ',')
    {
      *mem_addr_ptr = *mem_addr_ptr << 4;
      *mem_addr_ptr |= fromhex (ch) & 0x0f;
    }

  while ((ch = from[i++]) != ':')
    {
      *len_ptr = *len_ptr << 4;
      *len_ptr |= fromhex (ch) & 0x0f;
    }

  convert_ascii_to_int (&from[i++], to, *len_ptr);
}

/* Ask GDB for the address of NAME, and return it in ADDRP if found.
   Returns 1 if the symbol is found, 0 if it is not, -1 on error.  */

int
look_up_one_symbol (const char *name, CORE_ADDR *addrp)
{
  char own_buf[266], *p, *q;
  int len;
  struct sym_cache *sym;

  /* Check the cache first.  */
  for (sym = symbol_cache; sym; sym = sym->next)
    if (strcmp (name, sym->name) == 0)
      {
	*addrp = sym->addr;
	return 1;
      }

  /* Send the request.  */
  strcpy (own_buf, "qSymbol:");
  hexify (own_buf + strlen ("qSymbol:"), name, strlen (name));
  if (putpkt (own_buf) < 0)
    return -1;

  /* FIXME:  Eventually add buffer overflow checking (to getpkt?)  */
  len = getpkt (own_buf);
  if (len < 0)
    return -1;

  if (strncmp (own_buf, "qSymbol:", strlen ("qSymbol:")) != 0)
    {
      /* Malformed response.  */
      if (remote_debug)
	{
	  fprintf (stderr, "Malformed response to qSymbol, ignoring.\n");
	  fflush (stderr);
	}

      return -1;
    }

  p = own_buf + strlen ("qSymbol:");
  q = p;
  while (*q && *q != ':')
    q++;

  /* Make sure we found a value for the symbol.  */
  if (p == q || *q == '\0')
    return 0;

  decode_address (addrp, p, q - p);

  /* Save the symbol in our cache.  */
  sym = malloc (sizeof (*sym));
  sym->name = strdup (name);
  sym->addr = *addrp;
  sym->next = symbol_cache;
  symbol_cache = sym;

  return 1;
}