Initial revision

svn path=/trunk/; revision=6

1 files changed, 221 insertions, 0 deletions

diff --git a/daemon.c b/daemon.c
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+/* 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); 
+
+}