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
24#ifndef O_NONBLOCK
25#define O_NONBLOCK
26#endif
27
28static char *pidFile_name = NULL;
29
30/* return the pid in a pidfile. return 0 if the process (or pidfile)
31   does not exist */
32pid_t pidfile_pid(const char *name)
33{
34	int fd;
35	char pidstr[20];
36	pid_t pid;
37	unsigned int ret;
38	char * pidFile;
39
40	if (asprintf(&pidFile, "%s/%s.pid", lp_piddir(), name) == -1) {
41		return 0;
42	}
43
44	fd = sys_open(pidFile, O_NONBLOCK | O_RDONLY, 0644);
45	if (fd == -1) {
46		SAFE_FREE(pidFile);
47		return 0;
48	}
49
50	ZERO_ARRAY(pidstr);
51
52	if (read(fd, pidstr, sizeof(pidstr)-1) <= 0) {
53		goto noproc;
54	}
55
56	ret = atoi(pidstr);
57
58	if (ret == 0) {
59		/* Obviously we had some garbage in the pidfile... */
60		DEBUG(1, ("Could not parse contents of pidfile %s\n",
61			  pidFile));
62		goto noproc;
63	}
64
65	pid = (pid_t)ret;
66	if (!process_exists_by_pid(pid)) {
67		goto noproc;
68	}
69
70	if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_RDLCK)) {
71		/* we could get the lock - it can't be a Samba process */
72		goto noproc;
73	}
74
75	SAFE_FREE(pidFile);
76	close(fd);
77	return (pid_t)ret;
78
79 noproc:
80	close(fd);
81	unlink(pidFile);
82	SAFE_FREE(pidFile);
83	return 0;
84}
85
86/* create a pid file in the pid directory. open it and leave it locked */
87void pidfile_create(const char *program_name)
88{
89	int     fd;
90	char    buf[20];
91	const char    *short_configfile;
92	char *name;
93	pid_t pid;
94
95	/* Add a suffix to the program name if this is a process with a
96	 * none default configuration file name. */
97	if (strcmp( CONFIGFILE, get_dyn_CONFIGFILE()) == 0) {
98		name = SMB_STRDUP(program_name);
99	} else {
100		short_configfile = strrchr( get_dyn_CONFIGFILE(), '/');
101		if (short_configfile == NULL) {
102			/* conf file in current directory */
103			short_configfile = get_dyn_CONFIGFILE();
104		} else {
105			/* full/relative path provided */
106			short_configfile++;
107		}
108		if (asprintf(&name, "%s-%s", program_name,
109			     short_configfile) == -1) {
110			smb_panic("asprintf failed");
111		}
112	}
113
114	if (asprintf(&pidFile_name, "%s/%s.pid", lp_piddir(), name) == -1) {
115		smb_panic("asprintf failed");
116	}
117
118	pid = pidfile_pid(name);
119	if (pid != 0) {
120		DEBUG(0,("ERROR: %s is already running. File %s exists and process id %d is running.\n",
121			 name, pidFile_name, (int)pid));
122		exit(1);
123	}
124
125	fd = sys_open(pidFile_name, O_NONBLOCK | O_CREAT | O_WRONLY | O_EXCL,
126		      0644);
127	if (fd == -1) {
128		DEBUG(0,("ERROR: can't open %s: Error was %s\n", pidFile_name,
129			 strerror(errno)));
130		exit(1);
131	}
132
133	if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_WRLCK)==False) {
134		DEBUG(0,("ERROR: %s : fcntl lock of file %s failed. Error was %s\n",
135			 name, pidFile_name, strerror(errno)));
136		exit(1);
137	}
138
139	memset(buf, 0, sizeof(buf));
140	slprintf(buf, sizeof(buf) - 1, "%u\n", (unsigned int) sys_getpid());
141	if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf)) {
142		DEBUG(0,("ERROR: can't write to file %s: %s\n",
143			 pidFile_name, strerror(errno)));
144		exit(1);
145	}
146	/* Leave pid file open & locked for the duration... */
147	SAFE_FREE(name);
148}
149
150void pidfile_unlink(void)
151{
152	if (pidFile_name == NULL) {
153		return;
154	}
155	unlink(pidFile_name);
156	SAFE_FREE(pidFile_name);
157}
158