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
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
|
/* Copyright 1993-95 by Carl Harris, Jr.
* All rights reserved
*
* Distribute freely, except: don't remove my name from the source or
* documentation (don't take credit for my work), mark your changes (don't
* get me blamed for your possible bugs), don't alter or remove this
* notice. May be sold if buildable source is provided to buyer. No
* warrantee of any kind, express or implied, is included with this
* software; use at your own risk, responsibility for damages (if any) to
* anyone resulting from the use of this software rests entirely with the
* user.
*
* Send bug reports, bug fixes, enhancements, requests, flames, etc., and
* I'll try to keep a version up to date. I can be reached as follows:
* Carl Harris <ceharris@mal.com>
*/
/***********************************************************************
module: daemon
project: popclient
programmer: Carl Harris, ceharris@mal.com
description: This module contains all of the code needed to
turn a process into a daemon for POSIX, SysV, and
BSD systems.
$Log: daemon.c,v $
Revision 1.1 1996/06/25 14:32:01 esr
Initial revision
Revision 1.1 1995/08/14 18:36:38 ceharris
Patches to support POP3's LAST command.
Final revisions for beta3 release.
***********************************************************************/
#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/file.h>
#include <signal.h>
#include <fcntl.h>
#if defined(HAVE_SYS_WAIT_H)
# include <sys/wait.h>
#endif
#if defined(HAVE_UNISTD_H)
# include <unistd.h>
#endif
#include "popclient.h"
/******************************************************************
function: sigchld_handler
description: Process the SIGCHLD (a.k.a SIGCLD) signal by calling
a wait() variant to obtain the exit code of the
terminating process.
arguments: none.
ret. value: none (or undefined if REGSIGTYPE is int).
globals: none.
calls: none.
*****************************************************************/
RETSIGTYPE
sigchld_handler ()
{
pid_t pid;
#if defined(HAVE_UNION_WAIT)
union wait status;
#else
int status;
#endif
#if defined(HAVE_WAIT3)
while ((pid = wait3(&status, WNOHANG, (struct rusage *) 0)) > 0)
; /* swallow 'em up. */
#elif defined(HAVE_WAITPID)
while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
; /* swallow 'em up. */
#else /* Zooks! Nothing to do but wait(), and hope we don't block... */
wait(&status);
#endif
}
/******************************************************************
function: daemonize
description: become a daemon process; i.e. detach from the
control terminal, don't reacquire a control terminal,
become process group leader of our own process group,
and set up to catch child process termination signals.
arguments:
options command-line options.
ret. value: none.
globals: refers to the address of sigchld_handler().
calls: none.
*****************************************************************/
int
daemonize (options)
struct optrec *options;
{
int fd;
pid_t childpid;
RETSIGTYPE sigchild_handler();
/* if we are started by init (process 1) via /etc/inittab we needn't
bother to detach from our process group context */
if (getppid() == 1)
goto nottyDetach;
/* Ignore BSD terminal stop signals */
#ifdef SIGTTOU
signal(SIGTTOU, SIG_IGN);
#endif
#ifdef SIGTTIN
signal(SIGTTIN, SIG_IGN);
#endif
#ifdef SIGTSTP
signal(SIGTSTP, SIG_IGN);
#endif
/* In case we were not started in the background, fork and let
the parent exit. Guarantees that the child is not a process
group leader */
if ((childpid = fork()) < 0) {
perror("fork");
return(PS_IOERR);
}
else if (childpid > 0)
exit(0); /* parent */
/* Make ourselves the leader of a new process group with no
controlling terminal */
#if defined(HAVE_SETSID) /* POSIX */
/* POSIX makes this soooo easy to do */
if (setsid() < 0) {
perror("setsid");
return(PS_IOERR);
}
#elif defined(SIGTSTP) /* BSD */
/* change process group */
setpgrp(0, getpid());
/* lose controlling tty */
if ((fd = open("/dev/tty", O_RDWR)) >= 0) {
ioctl(fd, TIOCNOTTY, (char *) 0);
close(fd);
}
#else /* SVR3 and older */
/* change process group */
setpgrp();
/* lose controlling tty */
signal(SIGHUP, SIG_IGN);
if ((childpid = fork) < 0) {
perror("fork");
return(PS_IOERR);
}
else if (childpid > 0) {
exit(0); /* parent */
}
#endif
nottyDetach:
/* Close any/all open file descriptors */
#if defined(HAVE_GETDTABLESIZE)
for (fd = getdtablesize()-1; fd >= 0; fd--)
#elif defined(NOFILE)
for (fd = NOFILE-1; fd >= 0; fd--)
#else /* make an educated guess */
for (fd = 19; fd >= 0; fd--)
#endif
{
close(fd);
}
/* Reopen stdin descriptor on /dev/null */
if ((fd = open("/dev/null", O_RDWR)) < 0) { /* stdin */
perror("open: /dev/null");
return(PS_IOERR);
}
if (dup(fd) < 0) { /* stdout */
log_perror("dup");
return(PS_IOERR);
}
if (dup(fd) < 0) { /* stderr */
log_perror("dup");
return(PS_IOERR);
}
/* move to root directory, so we don't prevent filesystem unmounts */
chdir("/");
/* set our umask to something reasonable (we hope) */
#if defined(DEF_UMASK)
umask(DEF_UMASK);
#else
umask(022);
#endif
/* set up to catch child process termination signals */
signal(SIGCLD, sigchild_handler);
}
|
