r17727: Start pulling in changes for 3.0.23c
[Samba/gbeck.git] / source / lib / pidfile.c
blob08e41083b59946f0ef1ac29e33b61544961c997a
1 /* this code is broken - there is a race condition with the unlink (tridge) */
3 /*
4 Unix SMB/CIFS implementation.
5 pidfile handling
6 Copyright (C) Andrew Tridgell 1998
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 #include "includes.h"
25 #ifndef O_NONBLOCK
26 #define O_NONBLOCK
27 #endif
29 /* return the pid in a pidfile. return 0 if the process (or pidfile)
30 does not exist */
31 pid_t pidfile_pid(const char *name)
33 int fd;
34 char pidstr[20];
35 pid_t pid;
36 unsigned int ret;
37 pstring pidFile;
39 slprintf(pidFile, sizeof(pidFile)-1, "%s/%s.pid", lp_piddir(), name);
41 fd = sys_open(pidFile, O_NONBLOCK | O_RDONLY, 0644);
42 if (fd == -1) {
43 return 0;
46 ZERO_ARRAY(pidstr);
48 if (read(fd, pidstr, sizeof(pidstr)-1) <= 0) {
49 goto noproc;
52 ret = atoi(pidstr);
54 if (ret == 0) {
55 /* Obviously we had some garbage in the pidfile... */
56 DEBUG(1, ("Could not parse contents of pidfile %s\n",
57 pidFile));
58 goto noproc;
61 pid = (pid_t)ret;
62 if (!process_exists_by_pid(pid)) {
63 goto noproc;
66 if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_RDLCK)) {
67 /* we could get the lock - it can't be a Samba process */
68 goto noproc;
71 close(fd);
72 return (pid_t)ret;
74 noproc:
75 close(fd);
76 unlink(pidFile);
77 return 0;
80 /* create a pid file in the pid directory. open it and leave it locked */
81 void pidfile_create(const char *name)
83 int fd;
84 char buf[20];
85 pstring pidFile;
86 pid_t pid;
88 slprintf(pidFile, sizeof(pidFile)-1, "%s/%s.pid", lp_piddir(), name);
90 pid = pidfile_pid(name);
91 if (pid != 0) {
92 DEBUG(0,("ERROR: %s is already running. File %s exists and process id %d is running.\n",
93 name, pidFile, (int)pid));
94 exit(1);
97 fd = sys_open(pidFile, O_NONBLOCK | O_CREAT | O_WRONLY | O_EXCL, 0644);
98 if (fd == -1) {
99 DEBUG(0,("ERROR: can't open %s: Error was %s\n", pidFile,
100 strerror(errno)));
101 exit(1);
104 if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_WRLCK)==False) {
105 DEBUG(0,("ERROR: %s : fcntl lock of file %s failed. Error was %s\n",
106 name, pidFile, strerror(errno)));
107 exit(1);
110 memset(buf, 0, sizeof(buf));
111 slprintf(buf, sizeof(buf) - 1, "%u\n", (unsigned int) sys_getpid());
112 if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf)) {
113 DEBUG(0,("ERROR: can't write to file %s: %s\n",
114 pidFile, strerror(errno)));
115 exit(1);
117 /* Leave pid file open & locked for the duration... */