Initial import

[samba] / source / lib / pidfile.c

diff --git a/source/lib/pidfile.c b/source/lib/pidfile.c
new file mode 100644 (file)
index 0000000..b041eb7
--- /dev/null
+++ b/source/lib/pidfile.c
@@ -0,0 +1,116 @@
+/* this code is broken - there is a race condition with the unlink (tridge) */
+
+/* 
+   Unix SMB/CIFS implementation.
+   pidfile handling
+   Copyright (C) Andrew Tridgell 1998
+   
+   This program 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.
+   
+   This program 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 this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+
+#ifndef O_NONBLOCK
+#define O_NONBLOCK
+#endif
+
+/* return the pid in a pidfile. return 0 if the process (or pidfile)
+   does not exist */
+pid_t pidfile_pid(const char *name)
+{
+       int fd;
+       char pidstr[20];
+       unsigned ret;
+       pstring pidFile;
+
+       slprintf(pidFile, sizeof(pidFile)-1, "%s/%s.pid", lp_piddir(), name);
+
+       fd = sys_open(pidFile, O_NONBLOCK | O_RDONLY, 0644);
+       if (fd == -1) {
+               return 0;
+       }
+
+       ZERO_ARRAY(pidstr);
+
+       if (read(fd, pidstr, sizeof(pidstr)-1) <= 0) {
+               goto noproc;
+       }
+
+       ret = atoi(pidstr);
+
+       if (ret == 0) {
+               /* Obviously we had some garbage in the pidfile... */
+               DEBUG(1, ("Could not parse contents of pidfile %s\n",
+                         pidFile));
+               goto noproc;
+       }
+       
+       if (!process_exists_by_pid(ret)) {
+               goto noproc;
+       }
+
+       if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_RDLCK)) {
+               /* we could get the lock - it can't be a Samba process */
+               goto noproc;
+       }
+
+       close(fd);
+       return (pid_t)ret;
+
+ noproc:
+       close(fd);
+       unlink(pidFile);
+       return 0;
+}
+
+/* create a pid file in the pid directory. open it and leave it locked */
+void pidfile_create(const char *name)
+{
+       int     fd;
+       char    buf[20];
+       pstring pidFile;
+       pid_t pid;
+
+       slprintf(pidFile, sizeof(pidFile)-1, "%s/%s.pid", lp_piddir(), name);
+
+       pid = pidfile_pid(name);
+       if (pid != 0) {
+               DEBUG(0,("ERROR: %s is already running. File %s exists and process id %d is running.\n", 
+                        name, pidFile, (int)pid));
+               exit(1);
+       }
+
+       fd = sys_open(pidFile, O_NONBLOCK | O_CREAT | O_WRONLY | O_EXCL, 0644);
+       if (fd == -1) {
+               DEBUG(0,("ERROR: can't open %s: Error was %s\n", pidFile, 
+                        strerror(errno)));
+               exit(1);
+       }
+
+       if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_WRLCK)==False) {
+               DEBUG(0,("ERROR: %s : fcntl lock of file %s failed. Error was %s\n",  
+              name, pidFile, strerror(errno)));
+               exit(1);
+       }
+
+       memset(buf, 0, sizeof(buf));
+       slprintf(buf, sizeof(buf) - 1, "%u\n", (unsigned int) sys_getpid());
+       if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf)) {
+               DEBUG(0,("ERROR: can't write to file %s: %s\n", 
+                        pidFile, strerror(errno)));
+               exit(1);
+       }
+       /* Leave pid file open & locked for the duration... */
+}