/* 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" /** * @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 (!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); } 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); }