iostream.h File Reference

Generic abstraction for input/output streams. More...

#include "asterisk.h"

Include dependency graph for iostream.h:

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Macros
#define	DO_SSL   /* comment in/out if you want to support ssl */

Typedefs
typedef struct ssl_st	SSL
typedef struct ssl_ctx_st	SSL_CTX

Functions
int	ast_iostream_close (struct ast_iostream *stream)
	Close an iostream. More...
ssize_t	ast_iostream_discard (struct ast_iostream *stream, size_t count)
	Discard the specified number of bytes from an iostream. More...
struct ast_iostream *	ast_iostream_from_fd (int *fd)
	Create an iostream from a file descriptor. More...
int	ast_iostream_get_fd (struct ast_iostream *stream)
	Get an iostream's file descriptor. More...
SSL *	ast_iostream_get_ssl (struct ast_iostream *stream)
	Get a pointer to an iostream's OpenSSL SSL structure. More...
ssize_t	ast_iostream_gets (struct ast_iostream *stream, char *buffer, size_t size)
	Read a LF-terminated string from an iostream. More...
void	ast_iostream_nonblock (struct ast_iostream *stream)
	Make an iostream non-blocking. More...
ssize_t	ast_iostream_printf (struct ast_iostream *stream, const char *format,...)
	Write a formatted string to an iostream. More...
ssize_t	ast_iostream_read (struct ast_iostream *stream, void *buffer, size_t count)
	Read data from an iostream. More...
void	ast_iostream_set_exclusive_input (struct ast_iostream *stream, int exclusive_input)
	Set the iostream if it can exclusively depend upon the set timeouts. More...
void	ast_iostream_set_timeout_disable (struct ast_iostream *stream)
	Disable the iostream timeout timer. More...
void	ast_iostream_set_timeout_idle_inactivity (struct ast_iostream *stream, int timeout, int timeout_reset)
	Set the iostream inactivity & idle timeout timers. More...
void	ast_iostream_set_timeout_inactivity (struct ast_iostream *stream, int timeout)
	Set the iostream inactivity timeout timer. More...
void	ast_iostream_set_timeout_sequence (struct ast_iostream *stream, struct timeval start, int timeout)
	Set the iostream I/O sequence timeout timer. More...
int	ast_iostream_start_tls (struct ast_iostream **stream, SSL_CTX *ctx, int client)
	Begin TLS on an iostream. More...
int	ast_iostream_wait_for_input (struct ast_iostream *stream, int timeout)
	Wait for input on the iostream's file descriptor. More...
ssize_t	ast_iostream_write (struct ast_iostream *stream, const void *buffer, size_t count)
	Write data to an iostream. More...

Detailed Description

Generic abstraction for input/output streams.

Definition in file iostream.h.

Macro Definition Documentation

DO_SSL

#define DO_SSL   /* comment in/out if you want to support ssl */

Definition at line 31 of file iostream.h.

Typedef Documentation

SSL

typedef struct ssl_st SSL

Definition at line 37 of file iostream.h.

SSL_CTX

typedef struct ssl_ctx_st SSL_CTX

Definition at line 38 of file iostream.h.

Function Documentation

ast_iostream_close()

int ast_iostream_close

(

struct ast_iostream *

stream

)

Close an iostream.

Parameters

stream

A pointer to an iostream

Return values

0	success
-1	failure

Note

On failure, errno may be set providing additional information on why the failure occurred.

Definition at line 528 of file iostream.c.

References ao2_t_ref, ast_log, errno, ast_iostream::fd, LOG_ERROR, NULL, ast_iostream::ssl, and ssl_error_to_string().

Referenced by app_exec(), ast_tcptls_close_session_file(), ast_websocket_close(), auth_http_callback(), close_mansession_file(), generic_http_callback(), session_destroy_fn(), and session_instance_destructor().

{
   if (!stream) {
      errno = EBADF;
      return -1;
   }

   if (stream->fd != -1) {
#if defined(DO_SSL)
      if (stream->ssl) {
         int res;

         /*
          * According to the TLS standard, it is acceptable for an
          * application to only send its shutdown alert and then
          * close the underlying connection without waiting for
          * the peer's response (this way resources can be saved,
          * as the process can already terminate or serve another
          * connection).
          */
         res = SSL_shutdown(stream->ssl);
         if (res < 0) {
            int sslerr = SSL_get_error(stream->ssl, res);
            char err[256];
            ast_log(LOG_ERROR, "SSL_shutdown() failed: %s, %s\n",
               ERR_error_string(sslerr, err), ssl_error_to_string(sslerr, res));
         }

#if !defined(LIBRESSL_VERSION_NUMBER) && (OPENSSL_VERSION_NUMBER >= 0x10100000L)
         if (!SSL_is_server(stream->ssl)) {
#else
         if (!stream->ssl->server) {
#endif
            /* For client threads, ensure that the error stack is cleared */
#if defined(LIBRESSL_VERSION_NUMBER) || (OPENSSL_VERSION_NUMBER < 0x10100000L)
#if OPENSSL_VERSION_NUMBER >= 0x10000000L
            ERR_remove_thread_state(NULL);
#else
            ERR_remove_state(0);
#endif   /* OPENSSL_VERSION_NUMBER >= 0x10000000L */
#endif  /* OPENSSL_VERSION_NUMBER  < 0x10100000L */
         }

         SSL_free(stream->ssl);
         stream->ssl = NULL;
      }
#endif   /* defined(DO_SSL) */

      /*
       * Issuing shutdown() is necessary here to avoid a race
       * condition where the last data written may not appear
       * in the TCP stream.  See ASTERISK-23548
       */
      shutdown(stream->fd, SHUT_RDWR);
      if (close(stream->fd)) {
         ast_log(LOG_ERROR, "close() failed: %s\n", strerror(errno));
      }
      stream->fd = -1;
   }
   ao2_t_ref(stream, -1, "Closed ast_iostream");

   return 0;
}

ast_iostream_discard()

ssize_t ast_iostream_discard	(	struct ast_iostream *	stream,
		size_t	count
	)

Discard the specified number of bytes from an iostream.

Parameters

stream	A pointer to an iostream
count	The number of bytes to discard.

Returns

Upon successful completion, returns the number of bytes discarded. Otherwise, -1 is returned and errno may be set indicating the error.

Definition at line 357 of file iostream.c.

References ast_iostream_read(), and buf.

Referenced by http_body_discard_contents().

{
   char buf[1024];
   size_t remaining = size;
   ssize_t ret;

   while (remaining) {
      ret = ast_iostream_read(stream, buf, remaining > sizeof(buf) ? sizeof(buf) : remaining);
      if (ret <= 0) {
         return ret;
      }
      remaining -= ret;
   }

   return size;
}

ast_iostream_from_fd()

struct ast_iostream* ast_iostream_from_fd

(

int *

fd

)

Create an iostream from a file descriptor.

Parameters

fd	A pointer to an open file descriptor

Returns

A newly allocated iostream or NULL if allocation fails.

Definition at line 604 of file iostream.c.

References AO2_ALLOC_OPT_LOCK_NOLOCK, ao2_alloc_options, ast_iostream::fd, iostream_dtor(), ast_iostream::timeout, and ast_iostream::timeout_reset.

Referenced by app_exec(), ast_tcptls_client_create(), ast_tcptls_server_root(), auth_http_callback(), and generic_http_callback().

{
   struct ast_iostream *stream;

   stream = ao2_alloc_options(sizeof(*stream), iostream_dtor,
      AO2_ALLOC_OPT_LOCK_NOLOCK);
   if (stream) {
      stream->timeout = -1;
      stream->timeout_reset = -1;
      stream->fd = *fd;
      *fd = -1;
   }

   return stream;
}

ast_iostream_get_fd()

int ast_iostream_get_fd

(

struct ast_iostream *

stream

)

Get an iostream's file descriptor.

Parameters

stream

A pointer to an iostream

Returns

The file descriptor for the given iostream, or -1 if the iostream has no open file descriptor.

Definition at line 84 of file iostream.c.

References ast_iostream::fd.

Referenced by _sip_tcp_helper_thread(), action_waitevent(), ast_websocket_fd(), ast_websocket_uri_cb(), auth_http_callback(), eivr_comm(), get_input(), handle_showmanconn(), httpd_helper_thread(), process_output(), session_do(), sip_prepare_socket(), and sip_tcptls_read().

{
   return stream->fd;
}

ast_iostream_get_ssl()

SSL* ast_iostream_get_ssl

(

struct ast_iostream *

stream

)

Get a pointer to an iostream's OpenSSL SSL structure.

Parameters

stream

A pointer to an iostream

Returns

A pointer to the OpenSSL SSL structure for the given iostream, or NULL if TLS has not been initiated.

Note

If OpenSSL support is not included in the build, this will always return NULL.

Definition at line 108 of file iostream.c.

References ast_iostream::ssl.

Referenced by _sip_tcp_helper_thread(), ast_websocket_uri_cb(), handle_tcptls_connection(), sip_threadinfo_create(), and websocket_client_connect().

{
   return stream->ssl;
}

ast_iostream_gets()

ssize_t ast_iostream_gets	(	struct ast_iostream *	stream,
		char *	buffer,
		size_t	size
	)

Read a LF-terminated string from an iostream.

Parameters

stream	A pointer to an iostream
buffer	Pointer to a buffer to store the read bytes.
size	The total size of buffer in bytes.

Returns

The number of bytes stored in buffer, excluding the null byte used to terminate the string. If the size of buffer (indicated by the caller with the size argument) is not sufficient to store the entire line it will be truncated to fit the available space. The contents of buffer will always be terminated with a null byte. In the case of an error, -1 will be returned and errno may be set indicating the error.

Definition at line 300 of file iostream.c.

References iostream_read(), len(), ast_iostream::rbuf, ast_iostream::rbufhead, and ast_iostream::rbuflen.

Referenced by eivr_comm(), http_body_discard_chunk_trailer_headers(), http_body_get_chunk_length(), http_request_headers_get(), httpd_process_request(), and websocket_client_handshake_get_response().

{
   size_t remaining = size;
   ssize_t accum_size = 0;
   ssize_t len;
   char *newline;

   for (;;) {
      /* Search for newline */
      newline = memchr(stream->rbufhead, '\n', stream->rbuflen);
      if (newline) {
         len = newline - stream->rbufhead + 1;
         if (len > remaining - 1) {
            len = remaining - 1;
         }
         break;
      }

      /* Enough buffered line data to fill request buffer? */
      if (stream->rbuflen >= remaining - 1) {
         len = remaining - 1;
         break;
      }
      if (stream->rbuflen) {
         /* Put leftover buffered line data into request buffer */
         memcpy(buffer + accum_size, stream->rbufhead, stream->rbuflen);
         remaining -= stream->rbuflen;
         accum_size += stream->rbuflen;
         stream->rbuflen = 0;
      }
      stream->rbufhead = stream->rbuf;

      len = iostream_read(stream, stream->rbuf, sizeof(stream->rbuf));
      if (len == 0) {
         /* Nothing new was read.  Return whatever we have accumulated. */
         break;
      }
      if (len < 0) {
         if (accum_size) {
            /* We have an accumulated buffer so return that instead. */
            len = 0;
            break;
         }
         return len;
      }
      stream->rbuflen += len;
   }

   /* Return read buffer string length */
   memcpy(buffer + accum_size, stream->rbufhead, len);
   buffer[accum_size + len] = 0;
   stream->rbuflen -= len;
   stream->rbufhead += len;

   return accum_size + len;
}

ast_iostream_nonblock()

void ast_iostream_nonblock

(

struct ast_iostream *

stream

)

Make an iostream non-blocking.

Parameters

stream

A pointer to an iostream

Returns

Nothing

Definition at line 103 of file iostream.c.

References ast_fd_set_flags, and ast_iostream::fd.

Referenced by _sip_tcp_helper_thread(), ast_websocket_set_nonblock(), httpd_helper_thread(), and session_do().

{
   ast_fd_set_flags(stream->fd, O_NONBLOCK);
}

ast_iostream_printf()

ssize_t ast_iostream_printf	(	struct ast_iostream *	stream,
		const char *	format,
			...
	)

Write a formatted string to an iostream.

Parameters

stream	A pointer to an iostream
format	A format string, as documented by printf(3)
...	Arguments for the provided format string

Returns

The number of bytes written, or -1 if an error occurs. Note that if -1 is returned, the number of bytes written to the iostream is unspecified.

Definition at line 491 of file iostream.c.

References ast_free, ast_iostream_write(), ast_malloc, buf, error(), and len().

Referenced by ast_http_send(), ast_websocket_uri_cb(), and websocket_client_handshake().

{
   char sbuf[512], *buf = sbuf;
   int len, len2, ret = -1;
   va_list va;

   va_start(va, format);
   len = vsnprintf(buf, sizeof(sbuf), format, va);
   va_end(va);

   if (len > sizeof(sbuf) - 1) {
      /* Add one to the string length to accommodate the NULL byte */
      size_t buf_len = len + 1;

      buf = ast_malloc(buf_len);
      if (!buf) {
         return -1;
      }
      va_start(va, format);
      len2 = vsnprintf(buf, buf_len, format, va);
      va_end(va);
      if (len2 != len) {
         goto error;
      }
   }

   if (ast_iostream_write(stream, buf, len) == len)
      ret = len;

error:
   if (buf != sbuf) {
      ast_free(buf);
   }

   return ret;
}

ast_iostream_read()

ssize_t ast_iostream_read	(	struct ast_iostream *	stream,
		void *	buffer,
		size_t	count
	)

Read data from an iostream.

Parameters

stream	A pointer to an iostream
buffer	Pointer to a buffer to store the read bytes.
count	The number of bytes to read.

Returns

Upon successful completion, returns a non-negative integer indicating the number of bytes actually read. Otherwise, returns -1 and may set errno to indicate the error.

Definition at line 273 of file iostream.c.

References errno, ast_iostream::fd, iostream_read(), ast_iostream::rbufhead, and ast_iostream::rbuflen.

Referenced by ast_iostream_discard(), get_input(), http_body_check_chunk_sync(), http_body_read_contents(), readmimefile(), sip_tcptls_read(), and ws_safe_read().

{
   if (!count) {
      /* You asked for no data you got no data. */
      return 0;
   }

   if (!stream || stream->fd == -1) {
      errno = EBADF;
      return -1;
   }

   /* Get any remains from the read buffer */
   if (stream->rbuflen) {
      size_t r = count;
      if (r > stream->rbuflen) {
         r = stream->rbuflen;
      }
      memcpy(buffer, stream->rbufhead, r);
      stream->rbuflen -= r;
      stream->rbufhead += r;
      return r;
   }

   return iostream_read(stream, buffer, count);
}

ast_iostream_set_exclusive_input()

void ast_iostream_set_exclusive_input	(	struct ast_iostream *	stream,
		int	exclusive_input
	)

Set the iostream if it can exclusively depend upon the set timeouts.

Parameters

stream	A pointer to an iostream
exclusive_input	TRUE if stream can exclusively wait for fd input. Otherwise, the stream will not wait for fd input. It will wait while trying to send data.

Note

The stream timeouts still need to be set.

Returns

Nothing

Definition at line 148 of file iostream.c.

References ast_assert, ast_iostream::exclusive_input, and NULL.

Referenced by _sip_tcp_helper_thread(), ast_websocket_set_nonblock(), ast_websocket_uri_cb(), httpd_helper_thread(), and session_do().

{
   ast_assert(stream != NULL);

   stream->exclusive_input = exclusive_input;
}

ast_iostream_set_timeout_disable()

void ast_iostream_set_timeout_disable

(

struct ast_iostream *

stream

)

Disable the iostream timeout timer.

Parameters

stream

A pointer to an iostream

Returns

Nothing

Definition at line 113 of file iostream.c.

References ast_assert, NULL, ast_iostream::timeout, and ast_iostream::timeout_reset.

Referenced by _sip_tcp_helper_thread(), ast_websocket_close(), ast_websocket_write(), send_string(), and session_do().

{
   ast_assert(stream != NULL);

   stream->timeout = -1;
   stream->timeout_reset = -1;
}

ast_iostream_set_timeout_idle_inactivity()

void ast_iostream_set_timeout_idle_inactivity	(	struct ast_iostream *	stream,
		int	timeout,
		int	timeout_reset
	)

Set the iostream inactivity & idle timeout timers.

Parameters

stream	A pointer to an iostream
timeout	Number of milliseconds to wait for initial data transfer with the peer.
timeout_reset	Number of milliseconds to wait for subsequent data transfer with the peer.

As an example, if you want to timeout a peer if they do not send an initial message within 5 seconds or if they do not send a message at least every 30 seconds, you would set timeout to 5000 and timeout_reset to 30000.

Note

Setting either of these timeouts to -1 will disable them.

Returns

Nothing

Definition at line 130 of file iostream.c.

References ast_assert, NULL, ast_iostream::start, ast_iostream::timeout, and ast_iostream::timeout_reset.

Referenced by httpd_helper_thread().

{
   ast_assert(stream != NULL);

   stream->start.tv_sec = 0;
   stream->timeout = timeout;
   stream->timeout_reset = timeout_reset;
}

ast_iostream_set_timeout_inactivity()

void ast_iostream_set_timeout_inactivity	(	struct ast_iostream *	stream,
		int	timeout
	)

Set the iostream inactivity timeout timer.

Parameters

stream	A pointer to an iostream
timeout	Number of milliseconds to wait for data transfer with the peer.

This is basically how much time we are willing to spend in an I/O call before we declare the peer unresponsive.

Note

Setting timeout to -1 disables the timeout.

Setting this timeout replaces the I/O sequence timeout timer.

Returns

Nothing

Definition at line 121 of file iostream.c.

References ast_assert, NULL, ast_iostream::start, ast_iostream::timeout, and ast_iostream::timeout_reset.

Referenced by ast_websocket_close(), and send_string().

{
   ast_assert(stream != NULL);

   stream->start.tv_sec = 0;
   stream->timeout = timeout;
   stream->timeout_reset = timeout;
}

ast_iostream_set_timeout_sequence()

void ast_iostream_set_timeout_sequence	(	struct ast_iostream *	stream,
		struct timeval	start,
		int	timeout
	)

Set the iostream I/O sequence timeout timer.

Parameters

stream	A pointer to an iostream
start	Time the I/O sequence timer starts.
timeout	Number of milliseconds from the start time before timeout.

This is how much time are we willing to allow the peer to complete an operation that can take several I/O calls. The main use is as an authentication timer with us.

Note

Setting timeout to -1 disables the timeout.

Setting this timeout replaces the inactivity timeout timer.

Returns

Nothing

Definition at line 139 of file iostream.c.

References ast_assert, NULL, ast_iostream::start, ast_iostream::timeout, and ast_iostream::timeout_reset.

Referenced by _sip_tcp_helper_thread(), ast_websocket_write(), and session_do().

{
   ast_assert(stream != NULL);

   stream->start = start;
   stream->timeout = timeout;
   stream->timeout_reset = timeout;
}

ast_iostream_start_tls()

int ast_iostream_start_tls	(	struct ast_iostream **	stream,
		SSL_CTX *	ctx,
		int	client
	)

Begin TLS on an iostream.

Parameters

stream	A pointer to an iostream pointer
ctx	A pointer to an SSL_CTX which will be passed to SSL_new()
client	Non-zero to indicate that we are the client, zero to indicate that we are the server.

Return values

0	success
-1	failure

Note

The iostream that is passed in stream may be replaced with a different one before this function returns.

On failure, errno may be set providing additional information on why the failure occurred.

Definition at line 620 of file iostream.c.

References ast_log, errno, ast_iostream::fd, LOG_ERROR, ast_iostream::ssl, and ssl_error_to_string().

Referenced by handle_tcptls_connection().

{
#ifdef DO_SSL
   struct ast_iostream *stream = *pstream;
   int (*ssl_setup)(SSL *) = client ? SSL_connect : SSL_accept;
   int res;

   stream->ssl = SSL_new(ssl_ctx);
   if (!stream->ssl) {
      ast_log(LOG_ERROR, "Unable to create new SSL connection\n");
      errno = ENOMEM;
      return -1;
   }

   /*
    * This function takes struct ast_iostream **, so it can chain
    * SSL over any ast_iostream. For now we assume it's a file descriptor.
    * But later this should instead use BIO wrapper to tie SSL to another
    * ast_iostream.
    */
   SSL_set_fd(stream->ssl, stream->fd);

   res = ssl_setup(stream->ssl);
   if (res <= 0) {
      int sslerr = SSL_get_error(stream->ssl, res);
      char err[256];

      ast_log(LOG_ERROR, "Problem setting up ssl connection: %s, %s\n",
         ERR_error_string(sslerr, err), ssl_error_to_string(sslerr, res));
      errno = EIO;
      return -1;
   }

   return 0;
#else
   ast_log(LOG_ERROR, "SSL not enabled in this build\n");
   errno = ENOTSUP;
   return -1;
#endif
}

ast_iostream_wait_for_input()

int ast_iostream_wait_for_input	(	struct ast_iostream *	stream,
		int	timeout
	)

Wait for input on the iostream's file descriptor.

Since

16.8.0

17.2.0

Parameters

stream	A pointer to an iostream
timeout	the number of milliseconds to wait

Return values

-1	if error occurred
0	if the timeout expired
1	if the stream is ready for reading

Definition at line 89 of file iostream.c.

References ast_wait_for_input(), ast_iostream::fd, and ast_iostream::ssl.

Referenced by ast_websocket_wait_for_input(), and ws_safe_read().

{
#if defined(DO_SSL)
   /* Because SSL is read in blocks, it's possible that the last time we read we
      got more than we asked for and it is now buffered inside OpenSSL. If that
      is the case, calling ast_wait_for_input() will block until the fd is ready
      for reading again, which might never happen. */
   if (stream->ssl && SSL_pending(stream->ssl)) {
      return 1;
   }
#endif
   return ast_wait_for_input(stream->fd, timeout);
}

ast_iostream_write()

ssize_t ast_iostream_write	(	struct ast_iostream *	stream,
		const void *	buffer,
		size_t	count
	)

Write data to an iostream.

Parameters

stream	A pointer to an iostream
buffer	Pointer to a buffer from which to read bytes.
count	The number of bytes from buffer to write.

Returns

Upon successful completion, returns the number of bytes actually written to the iostream. This number shall never be greater than count. Otherwise, returns -1 and may set errno to indicate the error.

Definition at line 374 of file iostream.c.

References ast_debug, ast_remaining_ms(), ast_tvnow(), ast_wait_for_input(), ast_wait_for_output(), errno, ast_iostream::fd, ast_iostream::ssl, ssl_error_to_string(), ast_iostream::start, and ast_iostream::timeout.

Referenced by _sip_tcp_helper_thread(), ast_http_send(), ast_iostream_printf(), ast_websocket_close(), ast_websocket_write(), process_output(), send_eivr_event(), and send_string().

{
   struct timeval start;
   int ms;
   int res;
   int written;
   int remaining;

   if (!size) {
      /* You asked to write no data you wrote no data. */
      return 0;
   }

   if (!stream || stream->fd == -1) {
      errno = EBADF;
      return -1;
   }

   if (stream->start.tv_sec) {
      start = stream->start;
   } else {
      start = ast_tvnow();
   }

#if defined(DO_SSL)
   if (stream->ssl) {
      written = 0;
      remaining = size;
      for (;;) {
         int sslerr;
         char err[256];
         res = SSL_write(stream->ssl, buffer + written, remaining);
         if (res == remaining) {
            /* Everything was written. */
            return size;
         }
         if (0 < res) {
            /* Successfully wrote part of the buffer.  Try to write the rest. */
            written += res;
            remaining -= res;
            continue;
         }
         sslerr = SSL_get_error(stream->ssl, res);
         switch (sslerr) {
         case SSL_ERROR_ZERO_RETURN:
            ast_debug(1, "TLS clean shutdown alert writing data\n");
            if (written) {
               /* Report partial write. */
               return written;
            }
            errno = EBADF;
            return -1;
         case SSL_ERROR_WANT_READ:
            ms = ast_remaining_ms(start, stream->timeout);
            if (!ms) {
               /* Report partial write. */
               ast_debug(1, "TLS timeout writing data (want read)\n");
               return written;
            }
            ast_wait_for_input(stream->fd, ms);
            break;
         case SSL_ERROR_WANT_WRITE:
            ms = ast_remaining_ms(start, stream->timeout);
            if (!ms) {
               /* Report partial write. */
               ast_debug(1, "TLS timeout writing data (want write)\n");
               return written;
            }
            ast_wait_for_output(stream->fd, ms);
            break;
         default:
            /* Undecoded SSL or transport error. */
            ast_debug(1, "TLS transport or SSL error writing data: %s, %s\n", ERR_error_string(sslerr, err),
               ssl_error_to_string(sslerr, res));
            if (written) {
               /* Report partial write. */
               return written;
            }
            errno = EBADF;
            return -1;
         }
      }
   }
#endif   /* defined(DO_SSL) */

   written = 0;
   remaining = size;
   for (;;) {
      res = write(stream->fd, buffer + written, remaining);
      if (res == remaining) {
         /* Yay everything was written. */
         return size;
      }
      if (0 < res) {
         /* Successfully wrote part of the buffer.  Try to write the rest. */
         written += res;
         remaining -= res;
         continue;
      }
      if (errno != EINTR && errno != EAGAIN) {
         /* Not a retryable error. */
         ast_debug(1, "TCP socket error writing: %s\n", strerror(errno));
         if (written) {
            return written;
         }
         return -1;
      }
      ms = ast_remaining_ms(start, stream->timeout);
      if (!ms) {
         /* Report partial write. */
         ast_debug(1, "TCP timeout writing data\n");
         return written;
      }
      ast_wait_for_output(stream->fd, ms);
   }
}