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/* $Id$ */
/***
This file is part of polypaudio.
polypaudio is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
polypaudio is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with polypaudio; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <limits.h>
#include <signal.h>
#include "pid.h"
#include "util.h"
#include "log.h"
/* Read the PID data from the file descriptor fd, and return it. If no
* pid could be read, return 0, on failure (pid_t) -1 */
static pid_t read_pid(const char *fn, int fd) {
ssize_t r;
char t[20], *e;
uint32_t pid;
assert(fn && fd >= 0);
if ((r = pa_loop_read(fd, t, sizeof(t)-1)) < 0) {
pa_log(__FILE__": WARNING: failed to read PID file '%s': %s\n", fn, strerror(errno));
return (pid_t) -1;
}
if (r == 0)
return (pid_t) 0;
t[r] = 0;
if ((e = strchr(t, '\n')))
*e = 0;
if (pa_atou(t, &pid) < 0) {
pa_log(__FILE__": WARNING: failed to parse PID file '%s'\n", fn);
return (pid_t) -1;
}
return (pid_t) pid;
}
static int open_pid_file(const char *fn, int mode) {
int fd = -1;
int lock = -1;
for (;;) {
struct stat st;
pa_make_secure_parent_dir(fn);
if ((fd = open(fn, mode, S_IRUSR|S_IWUSR)) < 0) {
if (mode != O_RDONLY || errno != ENOENT)
pa_log(__FILE__": WARNING: failed to open PID file '%s': %s\n", fn, strerror(errno));
goto fail;
}
/* Try to lock the file. If that fails, go without */
if (pa_lock_fd(fd, 1) < 0)
goto fail;
if (fstat(fd, &st) < 0) {
pa_log(__FILE__": Failed to fstat() PID file '%s': %s\n", fn, strerror(errno));
goto fail;
}
/* Does the file still exist in the file system? When ye, w're done, otherwise restart */
if (st.st_nlink >= 1)
break;
if (pa_lock_fd(fd, 0) < 0)
goto fail;
if (close(fd) < 0) {
pa_log(__FILE__": Failed to close file '%s': %s\n", fn, strerror(errno));
goto fail;
}
fd = -1;
}
return fd;
fail:
if (fd < 0) {
if (lock >= 0)
pa_lock_fd(fd, 0);
close(fd);
}
return -1;
}
/* Create a new PID file for the current process. */
int pa_pid_file_create(void) {
int fd = -1;
int ret = -1;
char fn[PATH_MAX];
char t[20];
pid_t pid;
size_t l;
pa_runtime_path("pid", fn, sizeof(fn));
if ((fd = open_pid_file(fn, O_CREAT|O_RDWR)) < 0)
goto fail;
if ((pid = read_pid(fn, fd)) == (pid_t) -1)
pa_log(__FILE__": corrupt PID file, overwriting.\n");
else if (pid > 0) {
if (kill(pid, 0) >= 0 || errno != ESRCH) {
pa_log(__FILE__": daemon already running.\n");
goto fail;
}
pa_log(__FILE__": stale PID file, overwriting.\n");
}
/* Overwrite the current PID file */
if (lseek(fd, 0, SEEK_SET) == (off_t) -1 || ftruncate(fd, 0) < 0) {
pa_log(__FILE__": failed to truncate PID fil: %s.\n", strerror(errno));
goto fail;
}
snprintf(t, sizeof(t), "%lu\n", (unsigned long) getpid());
l = strlen(t);
if (pa_loop_write(fd, t, l) != (ssize_t) l) {
pa_log(__FILE__": failed to write PID file.\n");
goto fail;
}
ret = 0;
fail:
if (fd >= 0) {
pa_lock_fd(fd, 0);
close(fd);
}
return ret;
}
/* Remove the PID file, if it is ours */
int pa_pid_file_remove(void) {
int fd = -1;
char fn[PATH_MAX];
int ret = -1;
pid_t pid;
pa_runtime_path("pid", fn, sizeof(fn));
if ((fd = open_pid_file(fn, O_RDWR)) < 0) {
pa_log(__FILE__": WARNING: failed to open PID file '%s': %s\n", fn, strerror(errno));
goto fail;
}
if ((pid = read_pid(fn, fd)) == (pid_t) -1)
goto fail;
if (pid != getpid()) {
pa_log(__FILE__": WARNING: PID file '%s' not mine!\n", fn);
goto fail;
}
if (ftruncate(fd, 0) < 0) {
pa_log(__FILE__": failed to truncate PID file '%s': %s\n", fn, strerror(errno));
goto fail;
}
if (unlink(fn) < 0) {
pa_log(__FILE__": failed to remove PID file '%s': %s\n", fn, strerror(errno));
goto fail;
}
ret = 0;
fail:
if (fd >= 0) {
pa_lock_fd(fd, 0);
close(fd);
}
return ret;
}
/* Check whether the daemon is currently running, i.e. if a PID file
* exists and the PID therein too. Returns 0 on succcess, -1
* otherwise. If pid is non-NULL and a running daemon was found,
* return its PID therein */
int pa_pid_file_check_running(pid_t *pid) {
return pa_pid_file_kill(0, pid);
}
/* Kill a current running daemon. Return non-zero on success, -1
* otherwise. If successful *pid contains the PID of the daemon
* process. */
int pa_pid_file_kill(int sig, pid_t *pid) {
int fd = -1;
char fn[PATH_MAX];
int ret = -1;
pid_t _pid;
if (!pid)
pid = &_pid;
pa_runtime_path("pid", fn, sizeof(fn));
if ((fd = open_pid_file(fn, O_RDONLY)) < 0)
goto fail;
if ((*pid = read_pid(fn, fd)) == (pid_t) -1)
goto fail;
ret = kill(*pid, sig);
fail:
if (fd >= 0) {
pa_lock_fd(fd, 0);
close(fd);
}
return ret;
}
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