summaryrefslogtreecommitdiffstats
path: root/source3/lib/pidfile.c
blob: b6a8e02b49dbd95e160bf9bee341191ad00fb19e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
/* 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"

#ifndef O_NONBLOCK
#define O_NONBLOCK
#endif

/* return the pid in a pidfile. return 0 if the process (or pidfile)
   does not exist */
pid_t pidfile_pid(const char *name)
{
	int fd;
	char pidstr[20];
	pid_t pid;
	unsigned int ret;
	char * pidFile;

	if (asprintf(&pidFile, "%s/%s.pid", lp_piddir(), name) == -1) {
		return 0;
	}

	fd = sys_open(pidFile, O_NONBLOCK | O_RDONLY, 0644);
	if (fd == -1) {
		SAFE_FREE(pidFile);
		return 0;
	}

	ZERO_ARRAY(pidstr);

	if (read(fd, pidstr, sizeof(pidstr)-1) <= 0) {
		goto noproc;
	}

	ret = atoi(pidstr);

	if (ret == 0) {
		/* Obviously we had some garbage in the pidfile... */
		DEBUG(1, ("Could not parse contents of pidfile %s\n",
			  pidFile));
		goto noproc;
	}
	
	pid = (pid_t)ret;
	if (!process_exists_by_pid(pid)) {
		goto noproc;
	}

	if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_RDLCK)) {
		/* we could get the lock - it can't be a Samba process */
		goto noproc;
	}

	SAFE_FREE(pidFile);
	close(fd);
	return (pid_t)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 *program_name)
{
	int     fd;
	char    buf[20];
	char    *short_configfile;
	char *name;
	char *pidFile;
	pid_t pid;

	/* Add a suffix to the program name if this is a process with a
	 * none default configuration file name. */
	if (strcmp( CONFIGFILE, dyn_CONFIGFILE) == 0) {
		name = SMB_STRDUP(program_name);
	} else {
		short_configfile = strrchr( dyn_CONFIGFILE, '/');
		if (short_configfile == NULL) {
			/* conf file in current directory */
			short_configfile = dyn_CONFIGFILE;
		} else {
			/* full/relative path provided */
			short_configfile++;
		}
		if (asprintf(&name, "%s-%s", program_name,
			     short_configfile) == -1) {
			smb_panic("asprintf failed");
		}
	}

	if (asprintf(&pidFile, "%s/%s.pid", lp_piddir(), name) == -1) {
		smb_panic("asprintf failed");
	}

	pid = pidfile_pid(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 = sys_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,SMB_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) sys_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(name);
	SAFE_FREE(pidFile);
}