X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=lock.c;h=213969f1f012f323c470ceb3a1e6b1c1aec43ffa;hb=cb8d898683ffccdf8de42a5b1236a6cf3cdbb6ce;hp=e56fe344359ad8dc031b76ca1719e124150d6fe1;hpb=ca4c478270ca3645015c94c8d5195a3d4aba1d6a;p=~andy%2Ffetchmail

diff --git a/lock.c b/lock.c
index e56fe344..213969f1 100644
--- a/lock.c
+++ b/lock.c
@@ -73,13 +73,14 @@ void fm_lock_dispose(void)
 
 int fm_lock_state(void)
 {
-    int		pid, st;
+    long	pid;
+    int		st;
     FILE	*lockfp;
     int		bkgd = FALSE;
 
     if ((lockfp = fopen(lockfile, "r")) != NULL)
     {
-	int args = fscanf(lockfp, "%d %d", &pid, &st);
+	int args = fscanf(lockfp, "%ld %d", &pid, &st);
 	bkgd = (args == 2);
 
 	if (ferror(lockfp)) {
@@ -91,12 +92,27 @@ int fm_lock_state(void)
 	fclose(lockfp); /* not checking should be safe, file mode was "r" */
 
 	if (args == EOF || args == 0 || kill(pid, 0) == -1) {
+	    /* ^ could not read PID  || process does not exist */
+	    /* => lockfile is stale, unlink it */
 	    pid = 0;
-
 	    fprintf(stderr,GT_("fetchmail: removing stale lockfile\n"));
 	    if (unlink(lockfile)) {
 	       if (errno != ENOENT) {
 		   perror(lockfile);
+		   /* we complain but we don't exit; it might be
+		    * writable for us, but in a directory we cannot
+		    * write to. This means we can write the new PID to
+		    * the file. Truncate to be safe in case the PID is
+		    * recycled by another process later.
+		    * \bug we should use fcntl() style locks or
+		    * something else instead in a future release. */
+		   if (truncate(lockfile, (off_t)0)) {
+		       /* but if we cannot truncate the file either,
+			* assume that we cannot write to it later,
+			* complain and quit. */
+		       perror(lockfile);
+		       exit(PS_EXCLUDE);
+		   }
 	       }
 	    }
 	}