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

alert_pipe

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

Definition at line 79 of file alertpipe.c.

{
#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);
}

References alert_pipe, and ast_alertpipe_clear().

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

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

alert_pipe

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.

{
    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;
}

References alert_pipe, 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().

ast_alertpipe_init()

int ast_alertpipe_init

(

int

alert_pipe[2]

)

Initialize an alert pipe.

Since

13.16.0

Parameters

alert_pipe

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

Return values

non-zero	if a failure occurred.
zero	otherwise.

Definition at line 38 of file alertpipe.c.

{
#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;
}

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

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

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

alert_pipe

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.

{
    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;
}

References alert_pipe, 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(), monitor_sig_flags(), and wait_for_signal_or_hangup().

ast_alertpipe_write()

ssize_t ast_alertpipe_write

(

int

alert_pipe[2]

)

Write an event to an alert pipe.

Since

13.16.0

Parameters

alert_pipe

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.

{
    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);
}

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

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