Most daemon will share the same code to daemonize(), we use

a generic one, lib/daemon.c, so any bug fix will impact the others and reduce maintainance/duplication. * lib/Makefile.am: Addition daemon.c * lib/daemon.c: New file. * pop3d/pop3d.c (pop3d_daemon_init): Use lib/daemon.c:daemon() code instead. * imap4d/imap4d.c (imap4d_daemon_init): Use lib/daemon.c:daemon code instead. * comstat/comstat.c (comstat_daemon_init): Use lib/daemon.c:daemon code instead. Remove trailing spaces.

Most daemon will share the same code to daemonize(), we use
a generic one, lib/daemon.c, so any bug fix will impact the others and reduce maintainance/duplication. * lib/Makefile.am: Addition daemon.c * lib/daemon.c: New file. * pop3d/pop3d.c (pop3d_daemon_init): Use lib/daemon.c:daemon() code instead. * imap4d/imap4d.c (imap4d_daemon_init): Use lib/daemon.c:daemon code instead. * comstat/comstat.c (comstat_daemon_init): Use lib/daemon.c:daemon code instead. Remove trailing spaces.
Alain Magloire
Commit 5a79e104 ... 5a79e104e2b745587db5532ec730d1c99384d111 authored 2001-11-11 19:25:36 +0000 by Alain Magloire
Showing 6 changed files with 254 additions and 132 deletions
ChangeLog
comsat/comsat.c
imap4d/imap4d.c
lib/Makefile.am
lib/daemon.c
pop3d/pop3d.c
--- a/ChangeLog
View file @5a79e10
+++ b/ChangeLog
View file @5a79e10
+2001-11-11  Alain Magloire
+	Most daemon will share the same code to daemonize(), we use
+	a generic one, lib/daemon.c, so any bug fix will impact the
+	others and reduce maintainance/duplication.
+	* lib/Makefile.am: Addition daemon.c
+	* lib/daemon.c: New file.
+	* pop3d/pop3d.c (pop3d_daemon_init): Use lib/daemon.c:daemon() code
+	instead.
+	* imap4d/imap4d.c (imap4d_daemon_init): Use lib/daemon.c:daemon code
+	instead.
+	* comstat/comstat.c (comstat_daemon_init): Use lib/daemon.c:daemon code
+	instead. Remove trailing spaces.
 2001-11-11  Sergey Poznyakoff
 	* comsat/action.c: (new) User-defined actions for comsat.
--- a/comsat/comsat.c
View file @5a79e10
+++ b/comsat/comsat.c
View file @5a79e10
@@ -21,7 +21,7 @@
 #ifndef PATH_DEV
 # define PATH_DEV "/dev"
-#endif 
+#endif
 #ifndef PATH_TTY_PFX
 # define PATH_TTY_PFX PATH_DEV
 #endif
@@ -96,7 +96,7 @@ main(int argc, char **argv)
 {
  int c;
  char *config_file = NULL;
  while ((c = getopt_long (argc, argv, short_options, long_options, NULL))
 	 != -1)
    {
@@ -171,7 +171,7 @@ sig_hup (int sig)
    syslog (LOG_ERR, "can't restart: not started with absolute pathname");
  else
    execvp (xargv[0], xargv);
  signal (sig, sig_hup);
 }
@@ -185,7 +185,7 @@ comsat_init ()
  list_append (bookie, path_record);
  gethostname (hostname, sizeof hostname);
  /* Set signal handlers */
  signal (SIGTTOU, SIG_IGN);
  signal (SIGCHLD, SIG_IGN);
@@ -196,46 +196,15 @@ comsat_init ()
 static void
 comsat_daemon_init (void)
 {
-  pid_t pid;
+  extern int daemon (int, int);
-  pid = fork ();
-  if (pid == -1)
-    {
-      perror ("fork failed:");
-      exit (EXIT_FAILURE);
-    }
-  else if (pid > 0)
-    exit (EXIT_SUCCESS);	/* Parent exits.  */
-  /* Child: */
-  signal (SIGHUP, sig_hup);
-  setsid ();			/* Become session leader.  */
+  /* Become a daemon. Take care to close inherited fds and to hold
+     first three one, in, out, err.  Do not do the chdir("/").   */
-  /* The second fork is to guarantee that the daemon cannot acquire a
+  if (daemon (1, 0) < 0)
-     controlling terminal.  */
-  pid = fork ();
-  if (pid == -1)
    {
-      perror("fork failed");
+      perror ("failed to become a daemon:");
      exit (EXIT_FAILURE);
    }
-  else if (pid > 0)
-    exit (EXIT_SUCCESS);	/* Parent exits.  */
-  /* Close inherited file descriptors.  */
-  {
-    size_t i, fdmax;
-#if defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
-    fdmax = sysconf(_SC_OPEN_MAX);
-#elif defined(HAVE_GETDTABLESIZE)
-    fdmax = getdtablesize ();*/
-#else
-    fdmax = 64;
-#endif
-    for (i = 0; i < fdmax; ++i)
-      close (i);
-  }
 }
 unsigned maxrequests = 16;       /* Maximum number of request allowed per
@@ -256,14 +225,14 @@ comsat_daemon (int port)
  unsigned overflow_count = 0; /* Number of overflows achieved during
 				  the current interval */
  time_t now;
  fd = socket (AF_INET, SOCK_DGRAM, 0);
  if (fd == -1)
    {
      syslog (LOG_CRIT, "socket: %m");
      exit (1);
    }
  memset (&local_sin, 0, sizeof local_sin);
  local_sin.sin_family = AF_INET;
  local_sin.sin_addr.s_addr = INADDR_ANY; /*FIXME*/
@@ -276,13 +245,13 @@ comsat_daemon (int port)
    }
  syslog (LOG_NOTICE, "GNU comsat started");
  last_request_time = last_overflow_time = time (NULL);
  while (1)
    {
      fd_set fdset;
      int rc;
      FD_ZERO (&fdset);
      FD_SET (fd, &fdset);
      rc = select (fd+1, &fdset, NULL, NULL, NULL);
@@ -316,7 +285,7 @@ comsat_daemon (int port)
 		overflow_count = 0;
 	      last_overflow_time = time (NULL);
 	    }
 	  if (now - last_request_time <= request_control_interval)
 	    reqcount++;
 	  else
@@ -341,7 +310,7 @@ comsat_main (int fd)
  char *p, *endp;
  size_t offset;
  char *path = NULL;
  len = sizeof sin_from;
  rdlen = recvfrom (fd, buffer, sizeof buffer, 0,
 		    (struct sockaddr*)&sin_from, &len);
@@ -359,9 +328,9 @@ comsat_main (int fd)
 	      inet_ntoa (sin_from.sin_addr));
      return 1;
    }
  syslog (LOG_INFO, "%d bytes from %s", rdlen, inet_ntoa (sin_from.sin_addr));
  buffer[rdlen] = 0;
  /* Parse the buffer */
@@ -399,7 +368,7 @@ comsat_main (int fd)
      syslog (LOG_ERR, "fork: %m");
      return 1;
    }
  if (pid > 0)
    {
      struct timeval tv;
@@ -408,7 +377,7 @@ comsat_main (int fd)
      select (0, NULL, NULL, NULL, &tv);
      kill (pid, SIGKILL); /* Just in case the child is hung */
      return 0;
-    }								      
+    }
  /* Child: do actual I/O */
  notify_user (buffer, tty, path, offset);
@@ -420,7 +389,7 @@ get_newline_str (FILE *fp)
 {
 #if defined(OPOST) && defined(ONLCR)
  struct termios tbuf;
  tcgetattr (fileno (fp), &tbuf);
  if ((tbuf.c_oflag & OPOST) && (tbuf.c_oflag & ONLCR))
    return "\n";
@@ -484,7 +453,7 @@ notify_user (char *user, char *device, char *path, off_t offset)
 	      path, strerror (status));
      return;
    }
  /* Read headers */
  size -= offset;
  blurb = malloc (size + 1);
@@ -514,7 +483,7 @@ notify_user (char *user, char *device, char *path, off_t offset)
  mailbox_set_stream (tmp, stream);
  mailbox_messages_count (tmp, &count);
  mailbox_get_message (tmp, 1, &msg);
  run_user_action (fp, cr, msg);
  fclose (fp);
 }
@@ -624,7 +593,7 @@ mailbox_path (const char *user)
 {
  struct passwd *pw;
  char *mailbox_name;
  pw = mu_getpwnam (user);
  if (!pw)
    {
@@ -638,7 +607,7 @@ mailbox_path (const char *user)
 			     + strlen (pw->pw_name) + 1, 1);
      sprintf (mailbox_name, "%s/%s", _PATH_MAILDIR, pw->pw_name);
    }
-  else 
+  else
    {
      mailbox_name = calloc (strlen (pw->pw_dir) + strlen ("/INBOX"), 1);
      sprintf (mailbox_name, "%s/INBOX", pw->pw_dir);
--- a/imap4d/imap4d.c
View file @5a79e10
+++ b/imap4d/imap4d.c
View file @5a79e10
@@ -102,7 +102,7 @@ main (int argc, char **argv)
 	case 'S':
 	  set_namespace (NS_SHARED, optarg);
 	  break;
        case 't':
          timeout = strtoul (optarg, NULL, 10);
          break;
@@ -145,7 +145,7 @@ main (int argc, char **argv)
 #ifdef USE_VIRTUAL_DOMAINS
  mu_register_getpwnam (getpwnam_virtual);
 #endif
  /* Set the signal handlers.  */
  signal (SIGINT, imap4d_signal);
  signal (SIGQUIT, imap4d_signal);
@@ -161,9 +161,11 @@ main (int argc, char **argv)
  if (mode == DAEMON)
    imap4d_daemon_init ();
+  else
-  /* Make sure we are in the root.  */
+    {
-  chdir ("/");
+      /* Make sure we are in the root.  */
+      chdir ("/");
+    }
  /* Set up for syslog.  */
  openlog ("gnu-imap4d", LOG_PID, LOG_FACILITY);
@@ -203,7 +205,7 @@ imap4d_mainloop (int infile, int outfile)
    imap4d_bye (ERR_NO_OFILE);
  setvbuf(ofile, NULL, _IOLBF, 0);
  syslog (LOG_INFO, "Incoming connection opened");
  /* log information on the connecting client */
@@ -240,43 +242,15 @@ imap4d_mainloop (int infile, int outfile)
 static void
 imap4d_daemon_init (void)
 {
-  pid_t pid;
+  extern int daemon (int, int);
-  pid = fork ();
+  /* Become a daemon. Take care to close inherited fds and to hold
-  if (pid == -1)
+     first three one, in, out, err   */
-    {
+  if (daemon (0, 0) < 0)
-      perror ("fork failed:");
-      exit (1);
-    }
-  else if (pid > 0)
-    exit (0);                   /* Parent exits.  */
-  setsid ();                    /* Become session leader.  */
-  signal (SIGHUP, SIG_IGN);     /* Ignore SIGHUP.  */
-  /* The second fork is to guarantee that the daemon cannot acquire a
-     controlling terminal.  */
-  pid = fork ();
-  if (pid == -1)
    {
      perror("fork failed:");
      exit (1);
    }
-  else if (pid > 0)
-    exit (0);                   /* Parent exits.  */
-  /* Close inherited file descriptors.  */
-  {
-    size_t i;
-#if defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
-    size_t fdlimit = sysconf(_SC_OPEN_MAX);
-#else
-    size_t fdlimit = 64;
-#endif
-    for (i = 0; i < fdlimit; ++i)
-      close (i);
-  }
  /* SIGCHLD is not ignore but rather use to do some simple load balancing.  */
 #ifdef HAVE_SIGACTION
--- a/lib/Makefile.am
View file @5a79e10
+++ b/lib/Makefile.am
View file @5a79e10
@@ -3,9 +3,9 @@ noinst_LIBRARIES = libmailutils.a
 SUBDIRS = posix
-INCLUDES = -I${top_srcdir}/include 
+INCLUDES = -I${top_srcdir}/include
-libmailutils_a_SOURCES = basename.c getopt.c getopt1.c md5.c mu_dbm.c getline.c \
+libmailutils_a_SOURCES = basename.c daemon.c getopt.c getopt1.c md5.c \
-  xstrdup.c xmalloc.c argcv.c
+                         mu_dbm.c getline.c xstrdup.c xmalloc.c argcv.c
 EXTRA_DIST = alloca.c fnmatch.c setenv.c snprintf.c strchrnul.c strndup.c \
  strnlen.c strtok_r.c strsignal.c xstrtol.c vasprintf.c malloc.c realloc.c \
--- a/lib/daemon.c 0 → 100644
View file @5a79e10
+++ b/lib/daemon.c 0 → 100644
View file @5a79e10
+/*-
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include <config.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#ifdef HAVE_PATHS_H
+# include <paths.h>
+#endif
+#ifndef _PATH_DEVNULL
+# define _PATH_DEVNULL   "/dev/null"
+#endif
+/*
+  According to Unix-FAQ maintained by Andrew Gierth:
+  1.fork() so the parent can exit, this returns control to the command
+  line or shell invoking your program. This step is required so that the
+  new process is guaranteed not to be a process group leader. The next
+  step, setsid(), fails if you're a process group leader.
+  2.setsid() to become a process group and session group leader. Since a
+  controlling terminal is associated with a session, and this new session
+  has not yet acquired a controlling terminal our process now has no
+  controlling terminal, which is a Good Thing for daemons.
+  3.fork() again so the parent, (the session group leader), can exit. This
+  means that we, as a non-session group leader, can never regain a
+  controlling terminal.
+  4.chdir("/") to ensure that our process doesn't keep any directory in use.
+  Failure to do this could make it so that an administrator couldn't unmount
+  a filesystem, because it was our current directory.
+  [Equivalently, we could change to any directory containing files important
+  to the daemon's operation.]
+  5.umask(0) so that we have complete control over the permissions of
+  anything we write. We don't know what umask we may have inherited.
+  [This step is optional]
+  6.close() fds 0, 1, and 2. This releases the standard in, out, and error
+  we inherited from our parent process. We have no way of knowing where
+  these fds might have been redirected to. Note that many daemons use
+  sysconf() to determine the limit _SC_OPEN_MAX. _SC_OPEN_MAX tells you the
+  maximun open files/process. Then in a loop, the daemon can close all
+  possible file descriptors. You have to decide if you need to do this or not.
+  If you think that there might be file-descriptors open you should close
+  them, since there's a limit on number of concurrent file descriptors.
+  7.Establish new open descriptors for stdin, stdout and stderr. Even if
+  you don't plan to use them, it is still a good idea to have them open.
+  The precise handling of these is a matter of taste; if you have a logfile,
+  for example, you might wish to open it as stdout or stderr, and open
+  `/dev/null' as stdin; alternatively, you could open `/dev/console' as
+  stderr and/or stdout, and `/dev/null' as stdin, or any other combination
+  that makes sense for your particular daemon.  */
+#define MAXFD 64
+void
+waitdaemon_timeout (int signo)
+{
+  int left;
+  (void)signo;
+  left = alarm (0);
+  signal (SIGALRM, SIG_DFL);
+  if (left == 0)
+    errx (1, "timed out waiting for child");
+}
+/* waitdaemon is like daemon, but optionally the parent pause up
+   until maxwait before exiting. Return -1, on error, otherwise
+   waitdaemon will return the pid of the parent.  */
+int
+waitdaemon (int nochdir, int noclose, int maxwait)
+{
+  int fd;
+  pid_t childpid;
+  pid_t ppid;
+  ppid = getpid ();
+  switch (childpid = fork ())
+    {
+    case -1: /* Something went wrong.  */
+      return (-1);
+    case 0:  /* In the child.  */
+      break;
+    default:   /* In the parent.  */
+      if (maxwait > 0)
+	{
+	  signal (SIGALRM, waitdaemon_timeout);
+	  alarm (maxwait);
+	  pause ();
+	}
+      _exit(0);
+    }
+  if (setsid () == -1)
+    return -1;
+  /* SIGHUP is ignore because when the session leader terminates
+     all process in the session (the second child) are sent the SIGHUP.  */
+  signal (SIGHUP, SIG_IGN);
+  switch (fork ())
+    {
+    case 0:
+      break;
+    case -1:
+      return -1;
+    default:
+      _exit (0);
+    }
+  if (!nochdir)
+    chdir ("/");
+  if (!noclose)
+    {
+      int i;
+      long fdlimit = -1;
+#if defined (HAVE_SYSCONF) && defined (_SC_OPEN_MAX)
+      fdlimit = sysconf (_SC_OPEN_MAX);
+#elif defined (HAVE_GETDTABLESIZE)
+      fdlimit = getdtablesize ();
+#endif
+      if (fdlimit == -1)
+	fdlimit = MAXFD;
+      for (i = 0; i < fdlimit; i++)
+	close (i);
+      fd = open (_PATH_DEVNULL, O_RDWR, 0);
+      if (fd != -1)
+	{
+	  dup2 (fd, STDIN_FILENO);
+	  dup2 (fd, STDOUT_FILENO);
+	  dup2 (fd, STDERR_FILENO);
+	  if (fd > 2)
+	    close (fd);
+	}
+    }
+  return ppid;
+}
+int
+daemon (int nochdir, int noclose)
+{
+  return (waitdaemon (nochdir, noclose, 0) == -1) ? -1 : 0;
+}
--- a/pop3d/pop3d.c
View file @5a79e10
+++ b/pop3d/pop3d.c
View file @5a79e10
@@ -151,9 +151,11 @@ main (int argc, char **argv)
  if (mode == DAEMON)
    pop3d_daemon_init ();
+  else
-  /* Make sure we are in the root directory.  */
+    {
-  chdir ("/");
+      /* Make sure we are in the root directory.  */
+      chdir ("/");
+    }
  /* Set up for syslog.  */
  openlog ("gnu-pop3d", LOG_PID, LOG_FACILITY);
@@ -179,43 +181,15 @@ main (int argc, char **argv)
 static void
 pop3d_daemon_init (void)
 {
-  pid_t pid;
+  extern int daemon (int, int);
-  pid = fork ();
-  if (pid == -1)
-    {
-      perror ("fork failed:");
-      exit (EXIT_FAILURE);
-    }
-  else if (pid > 0)
-    exit (EXIT_SUCCESS);	/* Parent exits.  */
-  setsid ();			/* Become session leader.  */
-  signal (SIGHUP, SIG_IGN);	/* Ignore SIGHUP.  */
+  /* Become a daemon. Take care to close inherited fds and to hold
+     first three one, in, out, err   */
-  /* The second fork is to guarantee that the daemon cannot acquire a
+  if (daemon (0, 0) < 0)
-     controlling terminal.  */
-  pid = fork ();
-  if (pid == -1)
    {
-      perror("fork failed:");
+      perror ("failed to become a daemon:");
      exit (EXIT_FAILURE);
    }
-  else if (pid > 0)
-    exit (EXIT_SUCCESS);	/* Parent exits.  */
-  /* Close inherited file descriptors.  */
-  {
-    size_t i;
-#if defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
-    size_t fdlimit = sysconf(_SC_OPEN_MAX);
-#else
-    size_t fdlimit = 64;
-#endif
-    for (i = 0; i < fdlimit; ++i)
-      close (i);
-  }
  /* SIGCHLD is not ignore but rather use to do some simple load balancing.  */
 #ifdef HAVE_SIGACTION