daemon.c revision bbe1b32b 
1/*
2
3Copyright (c) 1988  X Consortium
4
5Permission is hereby granted, free of charge, to any person obtaining
6a copy of this software and associated documentation files (the
7"Software"), to deal in the Software without restriction, including
8without limitation the rights to use, copy, modify, merge, publish,
9distribute, sublicense, and/or sell copies of the Software, and to
10permit persons to whom the Software is furnished to do so, subject to
11the following conditions:
12
13The above copyright notice and this permission notice shall be included
14in all copies or substantial portions of the Software.
15
16THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
17OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
19IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR
20OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22OTHER DEALINGS IN THE SOFTWARE.
23
24Except as contained in this notice, the name of the X Consortium shall
25not be used in advertising or otherwise to promote the sale, use or
26other dealings in this Software without prior written authorization
27from the X Consortium.
28
29*/
30/* $XFree86: xc/programs/xfs/os/daemon.c,v 1.12 2002/10/20 21:42:50 tsi Exp $ */
31
32#include <X11/Xos.h>
33#include <sys/types.h>
34#include <errno.h>
35#include <stdlib.h>
36
37#if defined(USG)
38# include <termios.h>
39#else
40# include <sys/ioctl.h>
41#endif
42#ifdef hpux
43# include <sys/ptyio.h>
44#endif
45
46#ifdef X_NOT_POSIX
47# define Pid_t int
48#else
49# define Pid_t pid_t
50#endif
51
52#include "os.h"
53
54#if defined(__GLIBC__) || defined(CSRG_BASED)
55#define HAS_DAEMON
56#endif
57
58#ifndef X_NOT_POSIX
59#define HAS_SETSID
60#endif
61
62#ifndef HAS_SETSID
63
64#define setsid() MySetsid()
65
66static Pid_t
67MySetsid(void)
68{
69#if defined(TIOCNOTTY) || defined(TCCLRCTTY) || defined(TIOCTTY)
70    int fd;
71#endif
72    int stat;
73
74    fd = open("/dev/tty", O_RDWR);
75    if (fd >= 0) {
76#if defined(USG) && defined(TCCLRCTTY)
77	int zero = 0;
78	(void) ioctl (fd, TCCLRCTTY, &zero);
79#elif (defined(SYSV) || defined(SVR4)) && defined(TIOCTTY)
80	int zero = 0;
81	(void) ioctl (i, TIOCTTY, &zero);
82#elif defined(TIOCNOTTY)
83	(void) ioctl (i, TIOCNOTTY, (char *) 0);    /* detach, BSD style */
84#endif
85        close(fd);
86    }
87
88#if defined(SYSV) || defined(__QNXNTO__)
89    return setpgrp();
90#else
91    return setpgid(0, getpid());
92#endif
93}
94
95#endif /* !HAS_SETSID */
96
97
98/* detach */
99void
100BecomeDaemon ()
101{
102    /* If our C library has the daemon() function, just use it. */
103#ifdef HAS_DAEMON
104    daemon (0, 0);
105#else
106
107    switch (fork()) {
108    case -1:
109	/* error */
110	FatalError("daemon fork failed, %s\n", strerror(errno));
111	break;
112    case 0:
113	/* child */
114	break;
115    default:
116	/* parent */
117	exit(0);
118    }
119
120    if (setsid() == -1)
121	FatalError("setting session id for daemon failed: %s\n",
122		   strerror(errno));
123
124    chdir("/");
125
126    close (0);
127    close (1);
128    close (2);
129
130    /*
131     * Set up the standard file descriptors.
132     */
133    (void) open ("/dev/null", O_RDWR);
134    (void) dup2 (0, 1);
135    (void) dup2 (0, 2);
136
137#endif /* HAS_DAEMON */
138}
139