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

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Revision 1.4 - (hide annotations)
Sat Jul 13 21:19:23 2002 UTC (21 years, 8 months ago) by lefcha
Branch: MAIN
Changes since 1.3: +10 -12 lines
File MIME type: text/plain
Replace fputc()/fputs() with printf().

1 lefcha 1.1 #include <stdio.h>
2 lefcha 1.2 #include <stdlib.h>
3 lefcha 1.1 #include <limits.h>
4     #include <string.h>
5     #include <errno.h>
6 lefcha 1.2 #include <sys/types.h>
7     #include <signal.h>
8 lefcha 1.1
9     #include "imapfilter.h"
10    
11    
12     extern char *home;
13 lefcha 1.4
14     static char *lockfile = NULL; /* Lock file to stop new imapfilter
15     processes. */
16 lefcha 1.1
17    
18     /*
19     * Create lockfile with the PID of imapfilter as its contents.
20     */
21     void lockfile_create(void)
22     {
23     FILE *fd;
24    
25     create_file(lockfile, S_IRUSR | S_IWUSR);
26    
27     fd = fopen(lockfile, "w");
28     if (!fd)
29     fatal(ERROR_FILE_OPEN, "imapfilter: opening lockfile; %s\n",
30     strerror(errno));
31 lefcha 1.4 fprintf(fd, "%s\n", ultostr(getpid(), 10));
32 lefcha 1.1 fclose(fd);
33     }
34    
35    
36     /*
37 lefcha 1.2 * Die if another instance of imapfilter is running.
38     */
39     void lockfile_check(void)
40     {
41     pid_t n;
42    
43     if ((n = lockfile_pid())) {
44     fprintf(stderr,
45 lefcha 1.4 "imapfilter: another imapfilter is running with pid %d\n", n);
46 lefcha 1.3 exit(ERROR_LOCKFILE);
47 lefcha 1.2 }
48     }
49    
50    
51     /*
52     * Check if lockfile exists and if so, return the PID of the other
53 lefcha 1.1 * imapfilter running.
54     */
55 lefcha 1.2 pid_t lockfile_pid(void)
56 lefcha 1.1 {
57     char lockf[PATH_MAX];
58     char line[LINE_MAX];
59     FILE *fd;
60 lefcha 1.2 pid_t n = 0;
61 lefcha 1.4
62 lefcha 1.1 snprintf(lockf, PATH_MAX, "%s/%s", home, ".imapfilter/lock");
63     lockfile = xstrdup(lockf);
64 lefcha 1.4
65 lefcha 1.1 if (exists_file(lockfile)) {
66     fd = fopen(lockfile, "r");
67     if (!fd)
68     fatal(ERROR_FILE_OPEN, "imapfilter: opening lockfile; %s\n",
69     strerror(errno));
70     if (fgets(line, LINE_MAX - 1, fd)) {
71 lefcha 1.2 errno = 0;
72     n = strtoul(line, NULL, 10);
73     if (errno)
74     n = 0;
75 lefcha 1.1 }
76 lefcha 1.2 fclose(fd);
77 lefcha 1.1 }
78 lefcha 1.2 return n;
79 lefcha 1.1 }
80    
81    
82     /*
83     * Unlink the lockfile.
84     */
85     int lockfile_remove(void)
86     {
87     if (!lockfile)
88     return 0;
89 lefcha 1.4
90 lefcha 1.1 if (remove(lockfile)) {
91     error("imapfilter: removing lockfile; %s\n", strerror(errno));
92     return ERROR_FILE_OPEN;
93     }
94     xfree(lockfile);
95 lefcha 1.4
96 lefcha 1.1 return 0;
97 lefcha 1.2 }
98    
99    
100     /*
101     * Kill the other instance of imapfilter (if one is running).
102     */
103     void kill_imapfilter(void)
104     {
105     pid_t n;
106 lefcha 1.3
107 lefcha 1.2 n = lockfile_pid();
108 lefcha 1.4
109 lefcha 1.2 if (n > 0) {
110     if (kill(n, SIGTERM))
111     fprintf(stderr, "imapfilter: killing process with pid %d; %s\n",
112     n, strerror(errno));
113 lefcha 1.3 lockfile_remove();
114 lefcha 1.2 exit(0);
115     } else {
116     fprintf(stderr, "imapfilter: no other imapfilter is running\n");
117     exit(ERROR_UNDEFINED);
118     }
119 lefcha 1.1 }

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