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comparison src/daemon.c @ 0:48d06780cf77

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author Carl Byington <carl@five-ten-sg.com>
date Tue, 13 May 2008 14:03:10 -0700
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-1:000000000000 0:48d06780cf77
1 /*Add by Sergey Shapovalov */
2 #include <unistd.h>
3 #include <stdlib.h>
4 #include <fcntl.h>
5 #include <signal.h>
6 #include <sys/types.h>
7 #include <sys/wait.h>
8 #include <errno.h>
9
10 /* closeall() -- close all FDs >= a specified value */
11
12 void closeall(int fd)
13 {
14 int fdlimit = sysconf(_SC_OPEN_MAX);
15
16 while (fd < fdlimit)
17 close(fd++);
18 }
19
20 /* daemon() - detach process from user and disappear into the background
21 * returns -1 on failure, but you can't do much except exit in that case
22 * since we may already have forked. This is based on the BSD version,
23 * so the caller is responsible for things like the umask, etc.
24 */
25
26 /* believed to work on all Posix systems */
27
28 int daemon(int nochdir, int noclose)
29 {
30 switch (fork())
31 {
32 case 0: break;
33 case -1: return -1;
34 default: _exit(0); /* exit the original process */
35 }
36
37 if (setsid() < 0) /* shoudn't fail */
38 return -1;
39
40 /* dyke out this switch if you want to acquire a control tty in */
41 /* the future -- not normally advisable for daemons */
42
43 switch (fork())
44 {
45 case 0: break;
46 case -1: return -1;
47 default: _exit(0);
48 }
49
50 if (!nochdir)
51 chdir("/");
52
53 if (!noclose)
54 {
55 closeall(0);
56 open("/dev/null",O_RDWR);
57 dup(0); dup(0);
58 }
59
60 return 0;
61 }