/[imapfilter]/imapfilter/lock.c
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Annotation of /imapfilter/lock.c

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Revision 1.17 - (hide annotations)
Fri Feb 13 13:18:37 2004 UTC (20 years, 1 month ago) by lefcha
Branch: MAIN
Changes since 1.16: +1 -0 lines
File MIME type: text/plain
Insert an empty line if the function has no local variables.

1 lefcha 1.1 #include <stdio.h>
2 lefcha 1.12 #include <stdlib.h>
3 lefcha 1.13 #include <sys/types.h>
4     #include <unistd.h>
5 lefcha 1.1 #include <string.h>
6     #include <errno.h>
7 lefcha 1.11 #include <limits.h>
8 lefcha 1.13 #include <sys/stat.h>
9 lefcha 1.11 #include <signal.h>
10 lefcha 1.1
11 lefcha 1.11 #include "config.h"
12 lefcha 1.1 #include "imapfilter.h"
13 lefcha 1.11 #include "pathnames.h"
14 lefcha 1.1
15    
16     extern char *home;
17 lefcha 1.4
18 lefcha 1.15 static char *lockfile = NULL; /* Lock file to stop new imapfilter processes. */
19 lefcha 1.1
20    
21 lefcha 1.11 pid_t lockfile_pid(void);
22    
23    
24 lefcha 1.1 /*
25     * Create lockfile with the PID of imapfilter as its contents.
26     */
27 lefcha 1.10 void
28     lockfile_create(void)
29 lefcha 1.1 {
30 lefcha 1.10 FILE *fd;
31 lefcha 1.1
32 lefcha 1.10 create_file(lockfile, S_IRUSR | S_IWUSR);
33 lefcha 1.1
34 lefcha 1.10 fd = fopen(lockfile, "w");
35     if (fd == NULL)
36 lefcha 1.16 fatal(ERROR_FILEOPEN, "opening lockfile; %s\n",
37 lefcha 1.10 strerror(errno));
38     fprintf(fd, "%s\n", ultostr(getpid(), 10));
39     fclose(fd);
40 lefcha 1.1 }
41    
42    
43     /*
44 lefcha 1.2 * Die if another instance of imapfilter is running.
45     */
46 lefcha 1.10 void
47     lockfile_check(void)
48 lefcha 1.2 {
49 lefcha 1.10 pid_t n;
50 lefcha 1.2
51 lefcha 1.10 if ((n = lockfile_pid())) {
52     errno = 0;
53     kill(n, 0);
54     if (errno == ESRCH) { /* Process does not exist. */
55     fprintf(stderr, "imapfilter: removing stale lockfile\n");
56     lockfile_remove();
57     } else {
58     fprintf(stderr,
59     "imapfilter: another imapfilter "
60     "is running with pid %d\n", (int)(n));
61     exit(ERROR_LOCKFILE);
62     }
63 lefcha 1.7 }
64 lefcha 1.2 }
65    
66    
67     /*
68     * Check if lockfile exists and if so, return the PID of the other
69 lefcha 1.1 * imapfilter running.
70     */
71 lefcha 1.10 pid_t
72     lockfile_pid(void)
73 lefcha 1.1 {
74 lefcha 1.10 char line[LINE_MAX];
75     char lockf[PATH_MAX];
76     FILE *fd;
77     pid_t n;
78    
79     n = 0;
80    
81 lefcha 1.16 snprintf(lockf, PATH_MAX, "%s/%s", home, PATHNAME_LOCK);
82 lefcha 1.10 lockfile = xstrdup(lockf);
83    
84     if (exists_file(lockfile)) {
85     fd = fopen(lockfile, "r");
86     if (fd == NULL)
87 lefcha 1.16 fatal(ERROR_FILEOPEN, "opening lockfile; %s\n",
88 lefcha 1.10 strerror(errno));
89     if (fgets(line, LINE_MAX - 1, fd)) {
90     errno = 0;
91     n = strtoul(line, NULL, 10);
92     if (errno)
93     n = 0;
94     }
95     fclose(fd);
96 lefcha 1.1 }
97 lefcha 1.10 return n;
98 lefcha 1.1 }
99    
100    
101     /*
102     * Unlink the lockfile.
103     */
104 lefcha 1.10 int
105     lockfile_remove(void)
106 lefcha 1.1 {
107 lefcha 1.17
108 lefcha 1.10 if (lockfile == NULL)
109     return 0;
110    
111     if (unlink(lockfile) && errno != ENOENT) {
112     error("removing lockfile; %s\n", strerror(errno));
113 lefcha 1.16 return ERROR_FILEOPEN;
114 lefcha 1.10 }
115 lefcha 1.1 return 0;
116 lefcha 1.2 }
117    
118    
119     /*
120     * Kill the other instance of imapfilter (if one is running).
121     */
122 lefcha 1.10 void
123     kill_imapfilter(void)
124 lefcha 1.2 {
125 lefcha 1.10 pid_t n;
126 lefcha 1.3
127 lefcha 1.10 n = lockfile_pid();
128 lefcha 1.4
129 lefcha 1.10 if (n > 0) {
130     if (kill(n, SIGTERM))
131     fprintf(stderr, "imapfilter: killing process with "
132     "pid %d; %s\n", (int)(n), strerror(errno));
133     lockfile_remove();
134     exit(0);
135     } else {
136     fprintf(stderr, "imapfilter: no other imapfilter is running\n");
137     exit(ERROR_UNDEFINED);
138     }
139 lefcha 1.1 }

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