Properly daemonise nslcd and only exit when ready

This introduces a new daemonize module that provides functions for
closing all file descriptors, redirecting stdin/stdout/stderr to
/dev/null and a function for backgrounding an application while only
exiting the original process after the daemon process has indicated
readiness.

This is used to exit the original process only after the listening
socket has been set up and the worker threads have been started.

1 files changed, 27 insertions, 14 deletions

diff --git a/nslcd/nslcd.c b/nslcd/nslcd.c
index b5881c4..bbe6547 100644
--- a/nslcd/nslcd.c
+++ b/nslcd/nslcd.c
@@ -2,7 +2,7 @@
    nslcd.c - ldap local connection daemon
 
    Copyright (C) 2006 West Consulting
-   Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Arthur de Jong
+   Copyright (C) 2006-2014 Arthur de Jong
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
@@ -53,7 +53,6 @@
 #ifndef HAVE_GETOPT_LONG
 #include "compat/getopt_long.h"
 #endif /* not HAVE_GETOPT_LONG */
-#include "compat/daemon.h"
 #include <dlfcn.h>
 #include <libgen.h>
 #include <limits.h>
@@ -65,6 +64,7 @@
 #include "compat/attrs.h"
 #include "compat/getpeercred.h"
 #include "compat/socket.h"
+#include "daemonize.h"
 
 /* read timeout is half a second because clients should send their request
    quickly, write timeout is 60 seconds because clients could be taking some
@@ -117,7 +117,7 @@ static void display_version(FILE *fp)
 {
   fprintf(fp, "%s\n", PACKAGE_STRING);
   fprintf(fp, "Written by Luke Howard and Arthur de Jong.\n\n");
-  fprintf(fp, "Copyright (C) 1997-2013 Luke Howard, Arthur de Jong and West Consulting\n"
+  fprintf(fp, "Copyright (C) 1997-2014 Luke Howard, Arthur de Jong and West Consulting\n"
               "This is free software; see the source for copying conditions.  There is NO\n"
               "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n");
 }
@@ -649,13 +649,7 @@ int main(int argc, char *argv[])
   struct timespec ts;
 #endif /* HAVE_PTHREAD_TIMEDJOIN_NP */
   /* close all file descriptors (except stdin/out/err) */
-  i = sysconf(_SC_OPEN_MAX) - 1;
-  /* if the system does not have OPEN_MAX just close the first 32 and
-     hope we closed enough */
-  if (i < 0)
-    i = 32;
-  for (; i > 3; i--)
-    close(i);
+  daemonize_closefds();
   /* parse the command line */
   parse_cmdline(argc, argv);
   /* clean the environment */
@@ -695,22 +689,34 @@ int main(int argc, char *argv[])
       exit(EXIT_FAILURE);
     }
   }
+  /* change directory */
+  if (chdir("/") != 0)
+  {
+    log_log(LOG_ERR, "chdir failed: %s", strerror(errno));
+    exit(EXIT_FAILURE);
+  }
   /* normal check for pidfile locked */
   if (is_locked(NSLCD_PIDFILE))
   {
-    log_log(LOG_ERR, "daemon may already be active, cannot acquire lock (%s): %s",
+    log_log(LOG_ERR, "nslcd may already be active, cannot acquire lock (%s): %s",
             NSLCD_PIDFILE, strerror(errno));
     exit(EXIT_FAILURE);
   }
   /* daemonize */
-  if ((!nslcd_debugging) && (!nslcd_nofork) && (daemon(0, 0) < 0))
+  if ((!nslcd_debugging) && (!nslcd_nofork))
   {
-    log_log(LOG_ERR, "unable to daemonize: %s", strerror(errno));
-    exit(EXIT_FAILURE);
+    if (daemonize_daemon() != 0)
+    {
+      log_log(LOG_ERR, "unable to daemonize: %s", strerror(errno));
+      exit(EXIT_FAILURE);
+    }
   }
   /* intilialize logging */
   if (!nslcd_debugging)
+  {
+    daemonize_redirect_stdio();
     log_startlogging();
+  }
   /* write pidfile */
   create_pidfile(NSLCD_PIDFILE);
   /* log start */
@@ -719,6 +725,7 @@ int main(int argc, char *argv[])
   if (atexit(exithandler))
   {
     log_log(LOG_ERR, "atexit() failed: %s", strerror(errno));
+    daemonize_ready(EXIT_FAILURE, "atexit() failed\n");
     exit(EXIT_FAILURE);
   }
   /* create socket */
@@ -760,6 +767,7 @@ int main(int argc, char *argv[])
     {
       log_log(LOG_ERR, "cannot setgid(%d): %s",
               (int)nslcd_cfg->gid, strerror(errno));
+      daemonize_ready(EXIT_FAILURE, "cannot setgid()\n");
       exit(EXIT_FAILURE);
     }
     log_log(LOG_DEBUG, "setgid(%d) done", (int)nslcd_cfg->gid);
@@ -771,6 +779,7 @@ int main(int argc, char *argv[])
     {
       log_log(LOG_ERR, "cannot setuid(%d): %s",
               (int)nslcd_cfg->uid, strerror(errno));
+      daemonize_ready(EXIT_FAILURE, "cannot setuid()\n");
       exit(EXIT_FAILURE);
     }
     log_log(LOG_DEBUG, "setuid(%d) done", (int)nslcd_cfg->uid);
@@ -792,6 +801,7 @@ int main(int argc, char *argv[])
   if (nslcd_threads == NULL)
   {
     log_log(LOG_CRIT, "main(): malloc() failed to allocate memory");
+    daemonize_ready(EXIT_FAILURE, "malloc() failed to allocate memory\n");
     exit(EXIT_FAILURE);
   }
   for (i = 0; i < nslcd_cfg->threads; i++)
@@ -800,6 +810,7 @@ int main(int argc, char *argv[])
     {
       log_log(LOG_ERR, "unable to start worker thread %d: %s",
               i, strerror(errno));
+      daemonize_ready(EXIT_FAILURE, "unable to start worker thread\n");
       exit(EXIT_FAILURE);
     }
   }
@@ -813,6 +824,8 @@ int main(int argc, char *argv[])
   install_sighandler(SIGTERM, sig_handler);
   install_sighandler(SIGUSR1, sig_handler);
   install_sighandler(SIGUSR2, SIG_IGN);
+  /* signal the starting process to exit because we can provide services now */
+  daemonize_ready(EXIT_SUCCESS, NULL);
   /* wait until we received a signal */
   while ((nslcd_receivedsignal == 0) || (nslcd_receivedsignal == SIGUSR1))
   {