fixed pidfile handling to check for a lock on the file, so we can be

sure it is a samba process that is running.

diff --git a/source/lib/pidfile.c b/source/lib/pidfile.c
index 52a3be875fc7df2b0ae0bf961fa67ec413a2c7f1..3e943577d804b1f80eaf6aa4dede8b7dc7917c12 100644 (file)
--- a/source/lib/pidfile.c
+++ b/source/lib/pidfile.c
@@ -32,26 +32,42 @@ extern int DEBUGLEVEL;
    does not exist */
 pid_t pidfile_pid(char *name)
 {
-       FILE *f;
+       int fd;
+       char pidstr[20];
        unsigned ret;
        pstring pidFile;
 
        slprintf(pidFile, sizeof(pidFile)-1, "%s/%s.pid", lp_lockdir(), name);
 
-       f = sys_fopen(pidFile, "r");
-       if (!f) {
+       fd = open(pidFile, O_NONBLOCK | O_RDWR);
+       if (fd == -1) {
                return 0;
        }
 
-       if (fscanf(f,"%u", &ret) != 1) {
-               fclose(f);
-               return 0;
+       ZERO_ARRAY(pidstr);
+
+       if (read(fd, pidstr, sizeof(pidstr)-1) <= 0) {
+               goto ok;
        }
-       fclose(f);
+
+       ret = atoi(pidstr);
        
-       if (!process_exists(ret)) return 0;
+       if (!process_exists(ret)) {
+               goto ok;
+       }
+
+       if (fcntl_lock(fd,SMB_F_SETLK,0,1,F_WRLCK)==False) {
+               /* we could get the lock - it can't be a Samba process */
+               goto ok;
+       }
 
+       close(fd);
        return (pid_t)ret;
+
+ ok:
+       close(fd);
+       unlink(pidFile);
+       return 0;
 }
 
 /* create a pid file in the lock directory. open it and leave it locked */
@@ -65,14 +81,14 @@ void pidfile_create(char *name)
        slprintf(pidFile, sizeof(pidFile)-1, "%s/%s.pid", lp_lockdir(), name);
 
        pid = pidfile_pid(name);
-    if (pid > 0 && process_exists(pid)) {
-      DEBUG(0,("ERROR: %s is already running. File %s exists and process id %d is running.\n", 
-            name, pidFile, pid));
-      exit(1);
-    }
-
-       fd = sys_open(pidFile, O_NONBLOCK | O_CREAT | O_WRONLY, 0644);
-       if (fd < 0) {
+       if (pid != 0) {
+               DEBUG(0,("ERROR: %s is already running. File %s exists and process id %d is running.\n", 
+                        name, pidFile, 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);
@@ -93,3 +109,4 @@ void pidfile_create(char *name)
        }
        /* Leave pid file open & locked for the duration... */
 }
+