From 2a957ed711497aacf5bc11599cca740f5ea21750 Mon Sep 17 00:00:00 2001
From: tron <tron@NetBSD.org>
Date: Fri, 19 Oct 2001 20:36:59 +0000
Subject: [PATCH] - Don't delete the pidfile if the process executing the
 cleanup handler   isn't the process who created it. - If a new basename is
 supplied remove the an old pidfile if it was created   by this process and
 create a new one as suggested by Jason Thorpe. This fixes PR lib/13357 by
 Greg A. Woods.

---
 lib/libutil/pidfile.3 |  7 +++--
 lib/libutil/pidfile.c | 66 ++++++++++++++++++++++++++++++++++---------
 2 files changed, 58 insertions(+), 15 deletions(-)

diff --git a/lib/libutil/pidfile.3 b/lib/libutil/pidfile.3
index 08be941fbc5b..67f67de93bd3 100644
--- a/lib/libutil/pidfile.3
+++ b/lib/libutil/pidfile.3
@@ -1,4 +1,4 @@
-.\"	$NetBSD: pidfile.3,v 1.2 2001/04/12 22:34:31 sommerfeld Exp $
+.\"	$NetBSD: pidfile.3,v 1.3 2001/10/19 20:36:59 tron Exp $
 .\"
 .\" Copyright (c) 1999 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -65,7 +65,10 @@ receives a fatal signal.
 .Pp
 Note that only the first invocation of
 .Nm
-causes a pid file to be written; subsequent invocations have no effect.
+causes a pid file to be written; subsequent invocations have no effect
+unless a new
+.Ar basename
+is supplied.
 .Sh SEE ALSO
 .Xr atexit 3
 .Sh HISTORY
diff --git a/lib/libutil/pidfile.c b/lib/libutil/pidfile.c
index 48199540aef9..58a688a291c4 100644
--- a/lib/libutil/pidfile.c
+++ b/lib/libutil/pidfile.c
@@ -1,11 +1,11 @@
-/*	$NetBSD: pidfile.c,v 1.4 2001/02/19 22:43:42 cgd Exp $	*/
+/*	$NetBSD: pidfile.c,v 1.5 2001/10/19 20:36:59 tron Exp $	*/
 
 /*-
  * Copyright (c) 1999 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
  * This code is derived from software contributed to The NetBSD Foundation
- * by Jason R. Thorpe.
+ * by Jason R. Thorpe and Matthias Scheler.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -26,7 +26,7 @@
  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+B * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
@@ -38,16 +38,20 @@
 
 #include <sys/cdefs.h>
 #if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: pidfile.c,v 1.4 2001/02/19 22:43:42 cgd Exp $");
+__RCSID("$NetBSD: pidfile.c,v 1.5 2001/10/19 20:36:59 tron Exp $");
 #endif
 
 #include <sys/param.h>
 #include <paths.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <unistd.h>
 #include <util.h>
 
+static int   pidfile_atexit_done;
+static pid_t pidfile_pid;
+static char *pidfile_basename;
 static char *pidfile_path;
 
 static void pidfile_cleanup(void);
@@ -57,30 +61,66 @@ pidfile(const char *basename)
 {
 	FILE *f;
 
-	if (pidfile_path != NULL)
-		return;
+	/*
+	 * Register handler which will remove the pidfile later.
+	 */
+	if (!pidfile_atexit_done) {
+		if (atexit(pidfile_cleanup) < 0)
+			return;
+		pidfile_atexit_done = 1;
+	}
 
 	if (basename == NULL)
 		basename = getprogname();
 
+	/*
+	 * If pidfile has already been created for the supplied basename
+	 * we don't need to create a pidfile again.
+	 */
+	if (pidfile_path != NULL) {
+		if (strcmp(pidfile_basename, basename) == 0)
+			return;
+		/*
+		 * Remove existing pidfile if it was created by this process.
+		 */
+		pidfile_cleanup();
+
+		free(pidfile_path);
+		pidfile_path = NULL;
+		free(pidfile_basename);
+		pidfile_basename = NULL;
+	}
+
+	pidfile_pid = getpid();
+
+	pidfile_basename = strdup(basename);
+	if (pidfile_basename == NULL)
+		return;
+
 	/* _PATH_VARRUN includes trailing / */
 	(void) asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename);
-	if (pidfile_path == NULL)
+	if (pidfile_path == NULL) {
+		free(pidfile_basename);
+		pidfile_basename = NULL;
 		return;
+	}
 
-	if ((f = fopen(pidfile_path, "w")) == NULL)
+	if ((f = fopen(pidfile_path, "w")) == NULL) {
+		free(pidfile_path);
+		pidfile_path = NULL;
+		free(pidfile_basename);
+		pidfile_basename = NULL;
 		return;
+	}
 
-	(void) fprintf(f, "%d\n", getpid());
+	(void) fprintf(f, "%d\n", pidfile_pid);
 	(void) fclose(f);
-
-	(void) atexit(pidfile_cleanup);
 }
 
 static void
 pidfile_cleanup(void)
 {
-
-	if (pidfile_path != NULL)
+	/* Only remove the pidfile if it was created by this process. */
+	if ((pidfile_path != NULL) && (pidfile_pid == getpid()))
 		(void) unlink(pidfile_path);
 }