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
|
/*
* daemon.c -- turn a process into a daemon under POSIX, SYSV, BSD.
*
* For license terms, see the file COPYING in this directory.
*/
#include "config.h"
#include <stdio.h>
#include <errno.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif /* HAVE_FCNTL_H */
#ifdef HAVE_SYS_FCNTL_H
#include <sys/fcntl.h>
#endif /* HAVE_SYS_FCNTL_H */
#include <sys/stat.h> /* get umask(2) prototyped */
#if defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif
#if defined(STDC_HEADERS)
#include <stdlib.h>
#endif
#if defined(QNX)
#include <unix.h>
#endif
#if defined(HAVE_TERMIOS_H)
# include <termios.h> /* for TIOCNOTTY under Linux */
#endif
#if !defined(TIOCNOTTY) && defined(HAVE_SGTTY_H)
# include <sgtty.h> /* for TIOCNOTTY under NEXTSTEP */
#endif
/* BSD portability hack */
#if !defined(SIGCHLD) && defined(SIGCLD)
#define SIGCHLD SIGCLD
#endif
#include "fetchmail.h"
#include "tunable.h"
RETSIGTYPE
sigchld_handler (int sig)
/* process SIGCHLD to obtain the exit code of the terminating process */
{
pid_t pid;
#if defined(HAVE_UNION_WAIT)
union wait status;
#else
int status;
#endif
#if defined(HAVE_WAIT3)
#ifdef oldhpux /* HP-UX fixed this sometime between 9.01 and 10.20 */
while ((pid = wait3(&status, WNOHANG, (int *) 0)) > 0)
#else
while ((pid = wait3(&status, WNOHANG, (struct rusage *) 0)) > 0)
#endif
; /* 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
}
int
daemonize (const char *logfile, void (*termhook)(int))
/* detach from control TTY, become process group leader, catch SIGCHLD */
{
int fd;
pid_t childpid;
RETSIGTYPE sigchld_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) {
error(0, errno, "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) {
error(0, errno, "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) {
error(0, errno, "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 */
error(0, errno, "open: /dev/null");
return(PS_IOERR);
}
if (logfile)
fd = open(logfile, O_CREAT|O_WRONLY|O_APPEND, 0666); /* stdout */
else
if (dup(fd) < 0) { /* stdout */
error(0, errno, "dup");
return(PS_IOERR);
}
if (dup(fd) < 0) { /* stderr */
error(0, errno, "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(SIGCHLD, sigchld_handler);
#if defined(SIGPWR)
signal(SIGPWR, sigchld_handler);
#endif
return(0);
}
/* daemon.c ends here */
|
