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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2017, Sean Bright
*
* Sean Bright <sean.bright@gmail.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*! \file
*
* \brief Alert Pipe API
*
* \author Sean Bright
*/
#include "asterisk.h"
#include <unistd.h>
#include <fcntl.h>
#ifdef HAVE_EVENTFD
# include <sys/eventfd.h>
#endif
#include "asterisk/alertpipe.h"
#include "asterisk/logger.h"
int ast_alertpipe_init(int alert_pipe[2])
{
#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
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)) {
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ast_alertpipe_close(alert_pipe);
return -1;
}
}
return 0;
}
void ast_alertpipe_close(int alert_pipe[2])
{
#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_alert_status_t ast_alertpipe_read(int alert_pipe[2])
{
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;
}
ssize_t ast_alertpipe_write(int alert_pipe[2])
{
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);
}
ast_alert_status_t ast_alertpipe_flush(int alert_pipe[2])
{
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;
}