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

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Revision 1.18 - (hide annotations)
Sat Feb 14 19:14:43 2004 UTC (20 years, 1 month ago) by lefcha
Branch: MAIN
CVS Tags: HEAD
Changes since 1.17: +7 -5 lines
File MIME type: text/plain
Indentation.

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 lefcha 1.18 fprintf(stderr,
56     "imapfilter: removing stale lockfile\n");
57 lefcha 1.10 lockfile_remove();
58     } else {
59     fprintf(stderr,
60     "imapfilter: another imapfilter "
61     "is running with pid %d\n", (int)(n));
62     exit(ERROR_LOCKFILE);
63     }
64 lefcha 1.7 }
65 lefcha 1.2 }
66    
67    
68     /*
69 lefcha 1.18 * Check if lockfile exists and if so, return the PID of the other imapfilter
70     * running.
71 lefcha 1.1 */
72 lefcha 1.10 pid_t
73     lockfile_pid(void)
74 lefcha 1.1 {
75 lefcha 1.10 char line[LINE_MAX];
76     char lockf[PATH_MAX];
77     FILE *fd;
78     pid_t n;
79    
80     n = 0;
81    
82 lefcha 1.16 snprintf(lockf, PATH_MAX, "%s/%s", home, PATHNAME_LOCK);
83 lefcha 1.10 lockfile = xstrdup(lockf);
84    
85     if (exists_file(lockfile)) {
86     fd = fopen(lockfile, "r");
87     if (fd == NULL)
88 lefcha 1.16 fatal(ERROR_FILEOPEN, "opening lockfile; %s\n",
89 lefcha 1.10 strerror(errno));
90     if (fgets(line, LINE_MAX - 1, fd)) {
91     errno = 0;
92     n = strtoul(line, NULL, 10);
93     if (errno)
94     n = 0;
95     }
96     fclose(fd);
97 lefcha 1.1 }
98 lefcha 1.10 return n;
99 lefcha 1.1 }
100    
101    
102     /*
103     * Unlink the lockfile.
104     */
105 lefcha 1.10 int
106     lockfile_remove(void)
107 lefcha 1.1 {
108 lefcha 1.17
109 lefcha 1.10 if (lockfile == NULL)
110     return 0;
111    
112     if (unlink(lockfile) && errno != ENOENT) {
113     error("removing lockfile; %s\n", strerror(errno));
114 lefcha 1.16 return ERROR_FILEOPEN;
115 lefcha 1.10 }
116 lefcha 1.1 return 0;
117 lefcha 1.2 }
118    
119    
120     /*
121     * Kill the other instance of imapfilter (if one is running).
122     */
123 lefcha 1.10 void
124     kill_imapfilter(void)
125 lefcha 1.2 {
126 lefcha 1.10 pid_t n;
127 lefcha 1.3
128 lefcha 1.10 n = lockfile_pid();
129 lefcha 1.4
130 lefcha 1.10 if (n > 0) {
131     if (kill(n, SIGTERM))
132 lefcha 1.18 fprintf(stderr,
133     "imapfilter: killing process with pid %d; %s\n",
134     (int)(n), strerror(errno));
135 lefcha 1.10 lockfile_remove();
136     exit(0);
137     } else {
138     fprintf(stderr, "imapfilter: no other imapfilter is running\n");
139     exit(ERROR_UNDEFINED);
140     }
141 lefcha 1.1 }

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