1/* this code is broken - there is a race condition with the unlink (tridge) */
2
3/*
4   Unix SMB/CIFS implementation.
5   pidfile handling
6   Copyright (C) Andrew Tridgell 1998
7
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.
12
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.
17
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.
21*/
22
23#include "includes.h"
24
25#ifndef O_NONBLOCK
26#define O_NONBLOCK
27#endif
28
29/* return the pid in a pidfile. return 0 if the process (or pidfile)
30   does not exist */
31pid_t pidfile_pid(const char *name)
32{
33	int fd;
34	char pidstr[20];
35	unsigned ret;
36	pstring pidFile;
37
38	slprintf(pidFile, sizeof(pidFile)-1, "%s/%s.pid", lp_piddir(), name);
39
40	fd = sys_open(pidFile, O_NONBLOCK | O_RDONLY, 0644);
41	if (fd == -1) {
42		return 0;
43	}
44
45	ZERO_ARRAY(pidstr);
46
47	if (read(fd, pidstr, sizeof(pidstr)-1) <= 0) {
48		goto noproc;
49	}
50
51	ret = atoi(pidstr);
52
53	if (ret == 0) {
54		/* Obviously we had some garbage in the pidfile... */
55		DEBUG(1, ("Could not parse contents of pidfile %s\n",
56			  pidFile));
57		goto noproc;
58	}
59
60	if (!process_exists((pid_t)ret)) {
61		goto noproc;
62	}
63
64	if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_RDLCK)) {
65		/* we could get the lock - it can't be a Samba process */
66		goto noproc;
67	}
68
69	close(fd);
70	return (pid_t)ret;
71
72 noproc:
73	close(fd);
74	unlink(pidFile);
75	return 0;
76}
77
78/* create a pid file in the pid directory. open it and leave it locked */
79void pidfile_create(const char *name)
80{
81	int     fd;
82	char    buf[20];
83	pstring pidFile;
84	pid_t pid;
85
86	slprintf(pidFile, sizeof(pidFile)-1, "%s/%s.pid", lp_piddir(), name);
87
88	pid = pidfile_pid(name);
89	if (pid != 0) {
90		DEBUG(0,("ERROR: %s is already running. File %s exists and process id %d is running.\n",
91			 name, pidFile, (int)pid));
92		exit(1);
93	}
94
95	fd = sys_open(pidFile, O_NONBLOCK | O_CREAT | O_WRONLY | O_EXCL, 0644);
96	if (fd == -1) {
97		DEBUG(0,("ERROR: can't open %s: Error was %s\n", pidFile,
98			 strerror(errno)));
99		exit(1);
100	}
101
102	if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_WRLCK)==False) {
103		DEBUG(0,("ERROR: %s : fcntl lock of file %s failed. Error was %s\n",
104              name, pidFile, strerror(errno)));
105		exit(1);
106	}
107
108	memset(buf, 0, sizeof(buf));
109	slprintf(buf, sizeof(buf) - 1, "%u\n", (unsigned int) sys_getpid());
110	if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf)) {
111		DEBUG(0,("ERROR: can't write to file %s: %s\n",
112			 pidFile, strerror(errno)));
113		exit(1);
114	}
115	/* Leave pid file open & locked for the duration... */
116}
117