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
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
/* detach.c
Detach from the controlling terminal.
Copyright (C) 1992, 1993, 1995 Ian Lance Taylor
This file is part of the Taylor UUCP package.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
The author of the program may be contacted at ian@airs.com or
c/o Cygnus Support, 48 Grove Street, Somerville, MA 02144.
*/
/* $FreeBSD$ */
#include "uucp.h"
#include "uudefs.h"
#include "system.h"
#include "sysdep.h"
#include <errno.h>
#include <paths.h>
#if HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#ifdef TIOCNOTTY
#define HAVE_TIOCNOTTY 1
#else
#define HAVE_TIOCNOTTY 0
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#else
#if HAVE_SYS_FILE_H
#include <sys/file.h>
#endif
#endif
#ifndef O_RDONLY
#define O_RDONLY 0
#define O_WRONLY 1
#define O_RDWR 2
#endif
#if HAVE_BROKEN_SETSID
#undef HAVE_SETSID
#define HAVE_SETSID 0
#endif
/* Detach from the controlling terminal. This is called by uucico if
it is calling out to another system, so that it can receive SIGHUP
signals from the port it calls out on. It is also called by uucico
just before it starts uuxqt, so that uuxqt is completely
independent of the terminal. */
void
usysdep_detach ()
{
pid_t igrp;
/* Make sure that we can open the log file. We do this now so that,
if we can't, a message will be written to stderr. After we leave
this routine, stderr will be closed. */
ulog (LOG_NORMAL, (const char *) NULL);
/* Make sure we are not a process group leader. */
#if HAVE_BSD_PGRP
igrp = getpgrp (0);
#else
igrp = getpgrp ();
#endif
if (igrp == getpid ())
{
boolean fignored;
pid_t ipid;
/* Ignore SIGHUP, since our process group leader is about to
die. */
usset_signal (SIGHUP, SIG_IGN, FALSE, &fignored);
ipid = ixsfork ();
if (ipid < 0)
ulog (LOG_FATAL, "fork: %s", strerror (errno));
if (ipid != 0)
_exit (EXIT_SUCCESS);
/* We'll always wind up as a child of process number 1, right?
Right? We have to wait for our parent to die before
reenabling SIGHUP. */
while (getppid () != 1)
sleep (1);
ipid = getpid ();
ulog_id (ipid);
/* Restore SIGHUP catcher if it wasn't being ignored. */
if (! fignored)
usset_signal (SIGHUP, ussignal, TRUE, (boolean *) NULL);
DEBUG_MESSAGE2 (DEBUG_PORT,
"usysdep_detach: Forked; old PID %ld, new pid %ld",
(long) igrp, (long) ipid);
}
#if ! HAVE_SETSID && HAVE_TIOCNOTTY
/* Lose the original controlling terminal as well as our process
group. */
{
int o;
o = open ((char *) _PATH_TTY, O_RDONLY);
if (o >= 0)
{
(void) ioctl (o, TIOCNOTTY, (char *) NULL);
(void) close (o);
}
}
#endif /* ! HAVE_SETSID && HAVE_TIOCNOTTY */
/* Close stdin, stdout and stderr and reopen them on /dev/null, to
make sure we have no connection at all to the terminal. */
(void) close (0);
(void) close (1);
(void) close (2);
if (open ((char *) _PATH_DEVNULL, O_RDONLY) != 0
|| open ((char *) _PATH_DEVNULL, O_WRONLY) != 1
|| open ((char *) _PATH_DEVNULL, O_WRONLY) != 2)
ulog (LOG_FATAL, "open (%s): %s", _PATH_DEVNULL, strerror (errno));
#if HAVE_SETSID
/* Under POSIX the setsid call creates a new session for which we
are the process group leader. It also detaches us from our
controlling terminal. */
if (setsid () < 0)
ulog (LOG_ERROR, "setsid: %s", strerror (errno));
#else /* ! HAVE_SETSID */
#if ! HAVE_SETPGRP
#error Cannot detach from controlling terminal
#endif
/* If we don't have setsid, we must use setpgrp. On an old System V
system setpgrp will make us the leader of a new process group and
detach the controlling terminal. On an old BSD system the call
setpgrp (0, 0) will set our process group to 0 so that we can
acquire a new controlling terminal (TIOCNOTTY may or may not have
already done that anyhow). */
#if HAVE_BSD_PGRP
if (setpgrp (0, 0) < 0)
#else
if (setpgrp () < 0)
#endif
{
/* Some systems seem to give EPERM errors inappropriately. */
if (errno != EPERM)
ulog (LOG_ERROR, "setpgrp: %s", strerror (errno));
}
#endif /* ! HAVE_SETSID */
/* At this point we have completely detached from our controlling
terminal. The next terminal device we open will probably become
our controlling terminal. */
}
|
