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/* this code is broken - there is a race condition with the unlink (tridge) */
/*
Unix SMB/CIFS implementation.
pidfile handling
Copyright (C) Andrew Tridgell 1998
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "system/filesys.h"
#include "smbd/pidfile.h"
/**
* @file
* @brief Pid file handling
*/
/**
* return the pid in a pidfile. return 0 if the process (or pidfile)
* does not exist
*/
pid_t pidfile_pid(const char *piddir, const char *name)
{
int fd;
char pidstr[20];
pid_t ret;
char *pidFile;
if (asprintf(&pidFile, "%s/%s.pid", piddir, name) < 0) {
return 0;
}
fd = open(pidFile, O_NONBLOCK | O_RDONLY, 0644);
if (fd == -1) {
SAFE_FREE(pidFile);
return 0;
}
ZERO_STRUCT(pidstr);
if (read(fd, pidstr, sizeof(pidstr)-1) <= 0) {
goto noproc;
}
ret = (pid_t)atoi(pidstr);
if (ret <= 0) {
goto noproc;
}
if (!process_exists_by_pid(ret)) {
goto noproc;
}
if (fcntl_lock(fd,F_SETLK,0,1,F_RDLCK)) {
/* we could get the lock - it can't be a Samba process */
goto noproc;
}
close(fd);
SAFE_FREE(pidFile);
return ret;
noproc:
close(fd);
unlink(pidFile);
SAFE_FREE(pidFile);
return 0;
}
/**
* create a pid file in the pid directory. open it and leave it locked
*/
void pidfile_create(const char *piddir, const char *name)
{
int fd;
char buf[20];
char *pidFile;
pid_t pid;
if (asprintf(&pidFile, "%s/%s.pid", piddir, name) < 0) {
DEBUG(0,("ERROR: Out of memory\n"));
exit(1);
}
pid = pidfile_pid(piddir, name);
if (pid != 0) {
DEBUG(0,("ERROR: %s is already running. File %s exists and process id %d is running.\n",
name, pidFile, (int)pid));
exit(1);
}
fd = open(pidFile, O_NONBLOCK | O_CREAT | O_WRONLY | O_EXCL, 0644);
if (fd == -1) {
DEBUG(0,("ERROR: can't open %s: Error was %s\n", pidFile,
strerror(errno)));
exit(1);
}
smb_set_close_on_exec(fd);
if (fcntl_lock(fd,F_SETLK,0,1,F_WRLCK)==false) {
DEBUG(0,("ERROR: %s : fcntl lock of file %s failed. Error was %s\n",
name, pidFile, strerror(errno)));
exit(1);
}
memset(buf, 0, sizeof(buf));
slprintf(buf, sizeof(buf) - 1, "%u\n", (unsigned int) getpid());
if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf)) {
DEBUG(0,("ERROR: can't write to file %s: %s\n",
pidFile, strerror(errno)));
exit(1);
}
/* Leave pid file open & locked for the duration... */
SAFE_FREE(pidFile);
}
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