1 files changed, 91 insertions, 0 deletions
diff --git a/lib/pidfile.c b/lib/pidfile.c
new file mode 100644
index 0000000..f5ea4ff
--- /dev/null
+++ b/lib/pidfile.c
@@ -0,0 +1,91 @@
+/* Copyright (c) 2009, 2011 Thorsten Kukuk
+   Author: Thorsten Kukuk <kukuk@suse.de>
+
+   The YP Server is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The YP Server is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the YP Server; see the file COPYING. If
+   not, write to the Free Software Foundation, Inc., 51 Franklin Street,
+   Suite 500, Boston, MA 02110-1335, USA. */
+
+#include "pidfile.h"
+#include "log_msg.h"
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/file.h>
+#include <fcntl.h>
+
+void
+create_pidfile (const char *filename, const char *daemonname)
+{
+  int fd, left, written;
+  pid_t pid;
+  char pbuf[50], *ptr;
+  struct flock lock;
+
+  fd = open (filename, O_CREAT | O_RDWR | O_CLOEXEC,
+	     S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+  if (fd < 0)
+    {
+      log_msg ("cannot create pidfile %s", filename);
+      if (debug_flag)
+	log_msg ("\n");
+      exit (1);
+    }
+
+  lock.l_type = F_WRLCK;
+  lock.l_start = 0;
+  lock.l_whence = SEEK_SET;
+  lock.l_len = 0;
+
+  /* Is the pidfile locked by another daemon ? */
+  if (fcntl (fd, F_GETLK, &lock) < 0)
+    {
+      log_msg ("fcntl error");
+      if (debug_flag)
+	log_msg ("\n");
+      exit (1);
+    }
+  if (lock.l_type == F_UNLCK)
+    pid = 0;	        /* false, region is not locked by another proc */
+  else
+    pid = lock.l_pid;	/* true, return pid of lock owner */
+
+  if (0 != pid)
+    {
+      log_msg ("%s already running (pid %d) - exiting", daemonname, pid);
+      if (debug_flag)
+	log_msg ("\n");
+      exit (1);
+    }
+
+  /* write lock */
+  lock.l_type = F_WRLCK;
+  lock.l_start = 0;
+  lock.l_whence = SEEK_SET;
+  lock.l_len = 0;
+  if (0 != fcntl (fd, F_SETLK, &lock))
+    log_msg ("cannot lock pidfile");
+  sprintf (pbuf, "%ld\n", (long) getpid ());
+  left = strlen (pbuf);
+  ptr = pbuf;
+  while (left > 0)
+    {
+      if ((written = write (fd, ptr, left)) <= 0)
+	return;			/* error */
+      left -= written;
+      ptr += written;
+    }
+  return;
+}