Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

256 lines (225 sloc) 5.628 kb
/*-
* Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: src/lib/libutil/pidfile.c,v 1.9 2008/10/20 17:41:08 des Exp $
*/
#include <sys/param.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <time.h>
#include <err.h>
#include <errno.h>
#include <libutil.h>
#include "pidfile.h"
static int _pidfile_remove(struct pidfh *pfh, int freeit);
static int
pidfile_verify(struct pidfh *pfh)
{
struct stat sb;
if (pfh == NULL || pfh->pf_fd == -1)
return (EDOOFUS);
/*
* Check remembered descriptor.
*/
if (fstat(pfh->pf_fd, &sb) == -1)
return (errno);
if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
return (EDOOFUS);
return (0);
}
static int
pidfile_read(const char *path, pid_t *pidptr)
{
char buf[16], *endptr;
int error, fd, i;
fd = open(path, O_RDONLY);
if (fd == -1)
return (errno);
i = read(fd, buf, sizeof(buf) - 1);
error = errno; /* Remember errno in case close() wants to change it. */
close(fd);
if (i == -1)
return (error);
else if (i == 0)
return (EAGAIN);
buf[i] = '\0';
*pidptr = strtol(buf, &endptr, 10);
if (endptr != &buf[i])
return (EINVAL);
return (0);
}
struct pidfh *
pidfile_open(const char *path, mode_t mode, pid_t *pidptr)
{
struct pidfh *pfh;
struct stat sb;
int error, fd, len, count;
struct timespec rqtp;
pfh = malloc(sizeof(*pfh));
if (pfh == NULL)
return (NULL);
if (path == NULL)
len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
"/var/run/%s.pid", getprogname());
else
len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
"%s", path);
if (len >= (int)sizeof(pfh->pf_path)) {
free(pfh);
errno = ENAMETOOLONG;
return (NULL);
}
/*
* Open the PID file and obtain exclusive lock.
* We truncate PID file here only to remove old PID immediatelly,
* PID file will be truncated again in pidfile_write(), so
* pidfile_write() can be called multiple times.
*/
fd = flopen(pfh->pf_path,
O_WRONLY | O_CREAT | O_TRUNC | O_NONBLOCK, mode);
if (fd == -1) {
count = 0;
rqtp.tv_sec = 0;
rqtp.tv_nsec = 5000000;
if (errno == EWOULDBLOCK && pidptr != NULL) {
again:
errno = pidfile_read(pfh->pf_path, pidptr);
if (errno == 0)
errno = EEXIST;
else if (errno == EAGAIN) {
if (++count <= 3) {
nanosleep(&rqtp, 0);
goto again;
}
}
}
free(pfh);
return (NULL);
}
/*
* Remember file information, so in pidfile_write() we are sure we write
* to the proper descriptor.
*/
if (fstat(fd, &sb) == -1) {
error = errno;
unlink(pfh->pf_path);
close(fd);
free(pfh);
errno = error;
return (NULL);
}
pfh->pf_fd = fd;
pfh->pf_dev = sb.st_dev;
pfh->pf_ino = sb.st_ino;
return (pfh);
}
int
pidfile_write(struct pidfh *pfh)
{
char pidstr[16];
int error, fd;
/*
* Check remembered descriptor, so we don't overwrite some other
* file if pidfile was closed and descriptor reused.
*/
errno = pidfile_verify(pfh);
if (errno != 0) {
/*
* Don't close descriptor, because we are not sure if it's ours.
*/
return (-1);
}
fd = pfh->pf_fd;
/*
* Truncate PID file, so multiple calls of pidfile_write() are allowed.
*/
if (ftruncate(fd, 0) == -1) {
error = errno;
_pidfile_remove(pfh, 0);
errno = error;
return (-1);
}
snprintf(pidstr, sizeof(pidstr), "%u", getpid());
if (pwrite(fd, pidstr, strlen(pidstr), 0) != (ssize_t)strlen(pidstr)) {
error = errno;
_pidfile_remove(pfh, 0);
errno = error;
return (-1);
}
return (0);
}
int
pidfile_close(struct pidfh *pfh)
{
int error;
error = pidfile_verify(pfh);
if (error != 0) {
errno = error;
return (-1);
}
if (close(pfh->pf_fd) == -1)
error = errno;
free(pfh);
if (error != 0) {
errno = error;
return (-1);
}
return (0);
}
static int
_pidfile_remove(struct pidfh *pfh, int freeit)
{
int error;
error = pidfile_verify(pfh);
if (error != 0) {
errno = error;
return (-1);
}
if (unlink(pfh->pf_path) == -1)
error = errno;
if (close(pfh->pf_fd) == -1) {
if (error == 0)
error = errno;
}
if (freeit)
free(pfh);
else
pfh->pf_fd = -1;
if (error != 0) {
errno = error;
return (-1);
}
return (0);
}
int
pidfile_remove(struct pidfh *pfh)
{
return (_pidfile_remove(pfh, 1));
}
Jump to Line
Something went wrong with that request. Please try again.