source: trunk/samba/source/lib/pidfile.c @ 26

Last change on this file since 26 was 26, checked in by Paul Smedley, 14 years ago

Updated source to 3.0.25rc1

File size: 4.1 KB
Line 
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        pid_t pid;
36        unsigned int ret;
37        pstring pidFile;
38        slprintf(pidFile, sizeof(pidFile)-1, "%s/%s.pid", lp_piddir(), name);
39        fd = sys_open(pidFile, O_NONBLOCK | O_RDONLY, 0644);
40        if (fd == -1) {
41                return 0;
42        }
43
44        ZERO_ARRAY(pidstr);
45
46        if (read(fd, pidstr, sizeof(pidstr)-1) <= 0) {
47                goto noproc;
48        }
49
50        ret = atoi(pidstr);
51        if (ret == 0) {
52                /* Obviously we had some garbage in the pidfile... */
53                DEBUG(1, ("Could not parse contents of pidfile %s\n",
54                          pidFile));
55                goto noproc;
56        }
57       
58        pid = (pid_t)ret;
59
60        if (!process_exists_by_pid(pid)) {
61                goto noproc;
62        }
63
64#ifndef __OS2__
65        /* if we lock the file, we won't be able to read it later on OS/2 */
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;
69        }
70#endif
71        close(fd);
72        return (pid_t)ret;
73
74 noproc:
75        close(fd);
76        unlink(pidFile);
77        return 0;
78}
79
80/* create a pid file in the pid directory. open it and leave it locked */
81void pidfile_create(const char *program_name)
82{
83        int     fd;
84        char    buf[20];
85        char    *short_configfile;
86        pstring name;
87        pstring pidFile;
88        pid_t pid;
89#ifndef __OS2__
90        /* Add a suffix to the program name if this is a process with a
91         * none default configuration file name. */
92        if (strcmp( CONFIGFILE, dyn_CONFIGFILE) == 0) {
93                strncpy( name, program_name, sizeof( name)-1);
94        } else {
95                short_configfile = strrchr( dyn_CONFIGFILE, '/');
96                if (short_configfile == NULL) {
97                        /* conf file in current directory */
98                        short_configfile = dyn_CONFIGFILE;
99                } else {
100                        /* full/relative path provided */
101                        short_configfile++;
102                }
103                slprintf( name, sizeof( name)-1, "%s-%s", program_name, short_configfile+1);
104        }
105#else
106        /* On OS/2, CONFIGFILE will always be different to dyn_CONFIGFILE as dyn_CONFIGFILE dynamically looks up the system ETC directory */
107        strncpy( name, program_name, sizeof( name)-1);
108#endif
109        slprintf(pidFile, sizeof(pidFile)-1, "%s/%s.pid", lp_piddir(), name);
110
111        pid = pidfile_pid(name);
112        if (pid != 0) {
113                DEBUG(0,("ERROR: %s is already running. File %s exists and process id %d is running.\n", 
114                         name, pidFile, (int)pid));
115                exit(1);
116        }
117
118        fd = sys_open(pidFile, O_NONBLOCK | O_CREAT | O_WRONLY | O_EXCL, 0644);
119        if (fd == -1) {
120                DEBUG(0,("ERROR: can't open %s: Error was %s\n", pidFile, 
121                         strerror(errno)));
122                exit(1);
123        }
124
125        if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_WRLCK)==False) {
126                DEBUG(0,("ERROR: %s : fcntl lock of file %s failed. Error was %s\n", 
127              name, pidFile, strerror(errno)));
128                exit(1);
129        }
130
131        memset(buf, 0, sizeof(buf));
132        slprintf(buf, sizeof(buf) - 1, "%u\n", (unsigned int) sys_getpid());
133        if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf)) {
134                DEBUG(0,("ERROR: can't write to file %s: %s\n", 
135                         pidFile, strerror(errno)));
136                exit(1);
137        }
138#ifndef __OS2__
139        /* Leave pid file open & locked for the duration... */
140#else
141        /* If we leave the file open & locked on OS/2 - we can't read it, so close the fd */
142        close(fd);
143#endif
144}
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