alertpipe.c File Reference

Alert Pipe API. More...

#include "asterisk.h"
#include <unistd.h>
#include <fcntl.h>
#include <sys/eventfd.h>
#include "asterisk/alertpipe.h"
#include "asterisk/logger.h"

Include dependency graph for alertpipe.c:

Go to the source code of this file.

Functions
void	ast_alertpipe_close (int alert_pipe[2])
	Close an alert pipe. More...
ast_alert_status_t	ast_alertpipe_flush (int alert_pipe[2])
	Consume all alerts written to the alert pipe. More...
int	ast_alertpipe_init (int alert_pipe[2])
	Initialize an alert pipe. More...
ast_alert_status_t	ast_alertpipe_read (int alert_pipe[2])
	Read an event from an alert pipe. More...
ssize_t	ast_alertpipe_write (int alert_pipe[2])
	Write an event to an alert pipe. More...

Detailed Description

Alert Pipe API.

Author

Sean Bright

Definition in file alertpipe.c.

Function Documentation

ast_alertpipe_close()

void ast_alertpipe_close

(

int

alert_pipe[2]

)

Close an alert pipe.

Since

13.16.0

Parameters

p	a two-element containing the alert pipe's file descriptors

Definition at line 79 of file alertpipe.c.

References ast_alertpipe_clear().

Referenced by ast_alertpipe_init(), ast_channel_internal_alertpipe_close(), bridge_channel_destroy(), and really_quit().

{
#ifdef HAVE_EVENTFD

   if (alert_pipe[0] == alert_pipe[1]) {
      if (alert_pipe[0] > -1) {
         close(alert_pipe[0]);
         ast_alertpipe_clear(alert_pipe);
      }
      return;
   }

#endif

   if (alert_pipe[0] > -1) {
      close(alert_pipe[0]);
   }
   if (alert_pipe[1] > -1) {
      close(alert_pipe[1]);
   }
   ast_alertpipe_clear(alert_pipe);
}

ast_alertpipe_flush()

ast_alert_status_t ast_alertpipe_flush

(

int

alert_pipe[2]

)

Consume all alerts written to the alert pipe.

Since

13.16.0

Parameters

p	a two-element array containing the alert pipe's file descriptors

Return values

AST_ALERT_READ_SUCCESS	on success
AST_ALERT_NOT_READABLE	if the alert pipe is not readable
AST_ALERT_READ_FATAL	if the alert pipe's file descriptors are in blocking mode, or a read error occurs.

Definition at line 134 of file alertpipe.c.

References AST_ALERT_NOT_READABLE, AST_ALERT_READ_FAIL, AST_ALERT_READ_SUCCESS, ast_alertpipe_readable(), ast_log, errno, LOG_WARNING, and tmp().

Referenced by ast_channel_internal_alert_flush().

{
   int bytes_read;
   uint64_t tmp[16];

   if (!ast_alertpipe_readable(alert_pipe)) {
      return AST_ALERT_NOT_READABLE;
   }

   /* Read the alertpipe until it is exhausted. */
   for (;;) {
      bytes_read = read(alert_pipe[0], tmp, sizeof(tmp));
      if (bytes_read < 0) {
         if (errno == EINTR) {
            continue;
         }
         if (errno == EAGAIN || errno == EWOULDBLOCK) {
            /*
             * Would block so nothing left to read.
             * This is the normal loop exit.
             */
            break;
         }
         ast_log(LOG_WARNING, "read() failed flushing alertpipe: %s\n",
            strerror(errno));
         return AST_ALERT_READ_FAIL;
      }
      if (!bytes_read) {
         /* Read nothing so we are done */
         break;
      }
   }

   return AST_ALERT_READ_SUCCESS;
}

ast_alertpipe_init()

int ast_alertpipe_init

(

int

alert_pipe[2]

)

Initialize an alert pipe.

Since

13.16.0

Parameters

p	a two-element array to hold the alert pipe's file descriptors

Returns

non-zero if a failure occurred, zero otherwise.

Definition at line 38 of file alertpipe.c.

References ast_alertpipe_clear(), ast_alertpipe_close(), ast_fd_set_flags, ast_log, errno, and LOG_WARNING.

Referenced by ast_channel_internal_alertpipe_init(), asterisk_daemon(), and bridge_channel_internal_alloc().

{
#ifdef HAVE_EVENTFD

   int fd = eventfd(0, EFD_NONBLOCK | EFD_SEMAPHORE);
   if (fd > -1) {
      alert_pipe[0] = alert_pipe[1] = fd;
      return 0;
   }

   ast_log(LOG_WARNING, "Failed to create alert pipe with eventfd(), falling back to pipe(): %s\n",
      strerror(errno));
   ast_alertpipe_clear(alert_pipe);

#endif

#ifdef HAVE_PIPE2

   if (pipe2(alert_pipe, O_NONBLOCK)) {
      ast_log(LOG_WARNING, "Failed to create alert pipe: %s\n", strerror(errno));
      return -1;
   }

#else

   if (pipe(alert_pipe)) {
      ast_log(LOG_WARNING, "Failed to create alert pipe: %s\n", strerror(errno));
      return -1;
   } else {
      if (ast_fd_set_flags(alert_pipe[0], O_NONBLOCK)
         || ast_fd_set_flags(alert_pipe[1], O_NONBLOCK)) {
         ast_alertpipe_close(alert_pipe);
         return -1;
      }
   }

#endif

   return 0;
}

ast_alertpipe_read()

ast_alert_status_t ast_alertpipe_read

(

int

alert_pipe[2]

)

Read an event from an alert pipe.

Since

13.16.0

Parameters

p	a two-element array containing the alert pipe's file descriptors

Return values

AST_ALERT_READ_SUCCESS	on success
AST_ALERT_NOT_READABLE	if the alert pipe is not readable
AST_ALERT_READ_FATAL	if the alert pipe's file descriptors are in blocking mode, or a read error occurs.

Definition at line 102 of file alertpipe.c.

References AST_ALERT_NOT_READABLE, AST_ALERT_READ_FAIL, AST_ALERT_READ_SUCCESS, ast_alertpipe_readable(), ast_log, errno, LOG_WARNING, and tmp().

Referenced by ast_channel_internal_alert_read(), bridge_channel_handle_write(), and monitor_sig_flags().

{
   uint64_t tmp;

   if (!ast_alertpipe_readable(alert_pipe)) {
      return AST_ALERT_NOT_READABLE;
   }

   if (read(alert_pipe[0], &tmp, sizeof(tmp)) < 0) {
      if (errno != EINTR && errno != EAGAIN) {
         ast_log(LOG_WARNING, "read() failed: %s\n", strerror(errno));
         return AST_ALERT_READ_FAIL;
      }
   }

   return AST_ALERT_READ_SUCCESS;
}

ast_alertpipe_write()

ssize_t ast_alertpipe_write

(

int

alert_pipe[2]

)

Write an event to an alert pipe.

Since

13.16.0

Parameters

p	a two-element array containing the alert pipe's file descriptors

Return values

0	Success
1	Failure

Definition at line 120 of file alertpipe.c.

References ast_alertpipe_writable(), errno, and tmp().

Referenced by __quit_handler(), _hup_handler(), ast_bridge_channel_queue_frame(), and ast_channel_alert_write().

{
   uint64_t tmp = 1;

   if (!ast_alertpipe_writable(alert_pipe)) {
      errno = EBADF;
      return 0;
   }

   /* preset errno in case returned size does not match */
   errno = EPIPE;
   return write(alert_pipe[1], &tmp, sizeof(tmp)) != sizeof(tmp);
}