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
|
/*
pidfile.c - interact with pidfiles
Copyright (c) 1995 Martin Schulze <Martin.Schulze@Linux.DE>
This file is part of the sysklogd package, a kernel and system log daemon.
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 2 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, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/* left unaltered for tinc -- Ivo Timmermans */
/*
* Sat Aug 19 13:24:33 MET DST 1995: Martin Schulze
* First version (v0.2) released
*/
#include "system.h"
#include "pidfile.h"
#ifndef HAVE_MINGW
/* read_pid
*
* Reads the specified pidfile and returns the read pid.
* 0 is returned if either there's no pidfile, it's empty
* or no pid can be read.
*/
pid_t read_pid (const char *pidfile)
{
FILE *f;
long pid;
if (!(f=fopen(pidfile,"r")))
return 0;
if(fscanf(f,"%20ld", &pid) != 1)
pid = 0;
fclose(f);
return pid;
}
/* check_pid
*
* Reads the pid using read_pid and looks up the pid in the process
* table (using /proc) to determine if the process already exists. If
* so the pid is returned, otherwise 0.
*/
pid_t check_pid (const char *pidfile)
{
pid_t pid = read_pid(pidfile);
/* Amazing ! _I_ am already holding the pid file... */
if ((!pid) || (pid == getpid ()))
return 0;
/*
* The 'standard' method of doing this is to try and do a 'fake' kill
* of the process. If an ESRCH error is returned the process cannot
* be found -- GW
*/
/* But... errno is usually changed only on error.. */
errno = 0;
if (kill(pid, 0) && errno == ESRCH)
return 0;
return pid;
}
/* write_pid
*
* Writes the pid to the specified file. If that fails 0 is
* returned, otherwise the pid.
*/
pid_t write_pid (const char *pidfile)
{
FILE *f;
int fd;
pid_t pid;
if ((fd = open(pidfile, O_RDWR|O_CREAT, 0644)) == -1) {
return 0;
}
if ((f = fdopen(fd, "r+")) == NULL) {
close(fd);
return 0;
}
#ifdef HAVE_FLOCK
if (flock(fd, LOCK_EX|LOCK_NB) == -1) {
fclose(f);
return 0;
}
#endif
pid = getpid();
if (!fprintf(f,"%ld\n", (long)pid)) {
fclose(f);
return 0;
}
fflush(f);
#ifdef HAVE_FLOCK
if (flock(fd, LOCK_UN) == -1) {
fclose(f);
return 0;
}
#endif
fclose(f);
return pid;
}
/* remove_pid
*
* Remove the the specified file. The result from unlink(2)
* is returned
*/
int remove_pid (const char *pidfile)
{
return unlink (pidfile);
}
#endif
|
