blob: 40814e4756d9500ed7f82b95a200108d1065b8d3 (
plain)
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
|
/*
* Deamon-ify a user process; detach from controlling terminal and parent.
* $Id: daemon.c 1.2 Wed, 19 Mar 1997 12:44:53 -0500 dyfet $
* Copyright (c) 1997 by Tycho Softworks.
* For conditions on distribution and reuse see product license.
*
* Abstract:
* Daemon processes are commonly used in UNIX to build server
* applications. This module captures the essense of functionality
* required to make a process into a daemon within a single function
* call.
*
* Functions:
* daemon() - convert user process into a daemon.
*/
#include <proc/process.h>
#include <std/signal.h>
/* Daemonify a user process under UNIX.
*
* Abstract:
* In UNIX, a user process becomes a daemon by detaching itself from
* it's parent process and establishes it's own process group. A
* daemon may also detach itself from it's controlling terminal.
* This is usually accomplished through fork().
*
* Paramaters:
* flag - specifies daemon mode of operation:
* D_KEEPALL keeps all files open.
* D_KEEPSTDIO keeps stdio (stdin, stdout, stderr) open.
* D_KEEPNONIO detaches from stdio, keeps other files.
* D_KEEPNONE closes all open files.
*
* Returns:
* New pid of user process running as a daemon.
*
* Exceptions:
* Any failure terminates the process. No error message is possible
* since the process may already be detached from user I/O.
*/
pid_t pdetach(int flag)
{
pid_t pid;
int max = OPEN_MAX;
int i;
signal(SIGHUP, SIG_IGN);
i = 0;
if(flag == D_KEEPSTDIO)
i = 3;
if(flag == D_KEEPNONIO)
max = 3;
while((i < max) && (flag != D_KEEPALL))
close(i++);
pid = fork();
if(pid < 0)
return pid;
if(pid > 0)
exit(EX_OK);
setsid();
setpgid(0, getpid());
pid = fork();
if(pid < 0)
return pid;
if(pid > 0)
exit(EX_OK);
return getpid();
}
|
