home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
ftp.muug.mb.ca
/
2014.06.ftp.muug.mb.ca.tar
/
ftp.muug.mb.ca
/
pub
/
src
/
gopher
/
gopher1.01
/
mindexd
/
daemon.c
< prev
next >
Wrap
C/C++ Source or Header
|
1992-04-08
|
3KB
|
155 lines
#include "mindexd.h"
#define MY_BSD 1 /* System V signal handling doesn't seem to work
Correctly */
/*
* A BSD style SIGCLD signal handler that can be used by a server
* that's not interested in its child's exit status, but needs to
* wait for them, to avoid clogging up the system with zombies.
*
* Beware that the calling process may get an interrupted system
* call when we return, so they had better handle that.
*
* (From Stevens pg 82)
*/
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <signal.h>
#ifdef HP9000
#define TIOCNOTTY _IO('t', 113) /* void tty association */
#endif
sig_child()
{
#ifdef MY_BSD
/*
* Use the wait3() system call with the WNOHANG option
*/
int pid;
union wait status;
while ( (pid = wait3(&status, WNOHANG, (struct rusage *) 0)) > 0)
;
#endif
}
#include <stdio.h>
#include <sys/param.h>
#include <errno.h>
extern int errno;
#ifdef SIGTSTP /* True on a BSD system */
#include <sys/file.h>
#include <sys/ioctl.h>
#endif
/*
* Detach a daemon process from login session context
*/
daemon_start(ignsigcld)
int ignsigcld; /* Nonzero -> nuke zombie children */
{
register int childpid, fd;
/*
* If we were started by init (process 1) from the /etc/inittab
* file there's no need to detach.
*/
if (getppid() != 1) {
#ifdef SIGTTOU
signal(SIGTTOU, SIG_IGN);
#endif
#ifdef SIGTTIN
signal(SIGTTIN, SIG_IGN);
#endif
#ifdef SIGTSTP
signal(SIGTSTP, SIG_IGN);
#endif
/*
* If we were not started in the background, fork and let
* the parent exit. This also guarantees the first child
* is not a process group leader.
*/
if ( (childpid = fork()) < 0)
err_sys("can't fork first child");
else if (childpid >0)
exit(0); /* parent */
/*
* First Child process
*
* Disassociate from controlling terminal and process group.
* Ensure the process can't reacquire a new controlling terminal
*/
#ifdef SIGTSTP /* BSD */
if (setpgrp(0, getpid()) == -1)
err_sys("can't change process group");
if ( (fd = open("/dev/tty", O_RDWR)) >= 0) {
ioctl(fd, TIOCNOTTY, (char *)NULL); /* lose controlling TTY*/
close(fd);
}
#else /* System V */
if (setpgrp() == -1)
err_sys("Can't change process group");
signal(SIGHUP, SIG_IGN); /* immune from pgrp leader death */
if ( (childpid = fork()) < 0)
err_sys("Can't fork second child");
else if (childpid > 0)
exit(0); /* First child */
/* second child */
#endif
} /* End of if test for ppid == 1 */
/** Close any file descriptors **/
for (fd = 0; fd < NOFILE; fd++)
close(fd);
errno = 0; /* probably set to EBADF from a close */
/** Change the current directory to / **/
chdir("/");
/** Clear inherited file mode creation mask. **/
umask(0);
/*
* See if the caller isn't ineterested in the exit status of its
* children, and doesn't want to have them become zombies
*/
if (ignsigcld) {
#ifdef SIGTSTP
int sig_child();
signal(SIGCLD, sig_child); /* BSD */
#else
signal(SIGCLD, SIG_IGN); /* System V */
#endif
}
}