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 3 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, see <http://www.gnu.org/licenses/>.
20*/
21
22#include "includes.h"
23#include "system/filesys.h"
24
25/**
26 * @file
27 * @brief Pid file handling
28 */
29
30/**
31 * return the pid in a pidfile. return 0 if the process (or pidfile)
32 * does not exist
33 */
34pid_t pidfile_pid(const char *piddir, const char *name)
35{
36	int fd;
37	char pidstr[20];
38	pid_t ret;
39	char *pidFile;
40
41	asprintf(&pidFile, "%s/%s.pid", piddir, name);
42
43	fd = open(pidFile, O_NONBLOCK | O_RDONLY, 0644);
44
45	if (fd == -1) {
46		SAFE_FREE(pidFile);
47		return 0;
48	}
49
50	ZERO_STRUCT(pidstr);
51
52	if (read(fd, pidstr, sizeof(pidstr)-1) <= 0) {
53		goto noproc;
54	}
55
56	ret = (pid_t)atoi(pidstr);
57
58	if (!process_exists_by_pid(ret)) {
59		goto noproc;
60	}
61
62	if (fcntl_lock(fd,F_SETLK,0,1,F_RDLCK)) {
63		/* we could get the lock - it can't be a Samba process */
64		goto noproc;
65	}
66
67	close(fd);
68	SAFE_FREE(pidFile);
69	return ret;
70
71 noproc:
72	close(fd);
73	unlink(pidFile);
74	SAFE_FREE(pidFile);
75	return 0;
76}
77
78/**
79 * create a pid file in the pid directory. open it and leave it locked
80 */
81void pidfile_create(const char *piddir, const char *name)
82{
83	int     fd;
84	char    buf[20];
85	char *pidFile;
86	pid_t pid;
87
88	asprintf(&pidFile, "%s/%s.pid", piddir, name);
89
90	pid = pidfile_pid(piddir, 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);
95	}
96
97	fd = 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);
102	}
103
104	if (fcntl_lock(fd,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);
108	}
109
110	memset(buf, 0, sizeof(buf));
111	slprintf(buf, sizeof(buf) - 1, "%u\n", (unsigned int) 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);
116	}
117
118	/* Leave pid file open & locked for the duration... */
119	SAFE_FREE(pidFile);
120}
121