From 2ec8932c8c9cb71eb9f95e79cce195e64452dfd9 Mon Sep 17 00:00:00 2001
From: Craig Small <csmall@users.sourceforge.net>
Date: Mon, 18 Jul 2011 21:23:30 +1000
Subject: [PATCH] conditionally compile in fork for stat

---
 ChangeLog    |  1 +
 README       |  7 +++++++
 configure.ac | 10 ++++++++++
 src/fuser.c  | 15 ++++++++++-----
 4 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 815a8a3..4605f7f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,7 @@
 Changes in 22.15
 ================
 	* Really apply patch for SF#31110178 RH#651794
+	* Conditionally use fork before stat calls
 
 Changes in 22.14
 ================
diff --git a/README b/README
index 2489b05..2bc973f 100644
--- a/README
+++ b/README
@@ -17,6 +17,13 @@ They should work with most recent kernels. Man pages are included.
 src/loop.h was stolen from util-linux package which in turn stole it from
 the Linux kernel.
 
+fuser on network fs
+-------------------
+On network filesystems, fuser can hang because its trying to stat files
+that may go away.  If you use the --with-timeout-stat option during
+the configure step then fuser will fork a process to run stat. This means
+fuser doesn't hang, but it is much slower.
+
 Translations
 ------------
 My thanks for the various translators who have cheerfully given me the po
diff --git a/configure.ac b/configure.ac
index d9013d5..e8480cb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -24,6 +24,16 @@ if test "$enable_selinux" = "yes"; then
 fi
 AC_SUBST([SELINUX_LIB])
 
+dnl Call fork before all stat calls to stop hanging on NFS mounts
+AC_SUBST([WITH_TIMEOUT_STAT])
+AC_ARG_ENABLE([TIMEOUT_STAT],
+  [AS_HELP_STRING([--enable-timeout-stat], [Use a timeout on stat calls])],
+  [enable_timeout_stat=$enableval],
+  [enable_timeout_stat="no"])
+if test "$enable_timeout_stat" = "yes"; then
+  AC_DEFINE([WITH_timeout_stat], [1], [Use timeout on stat calls])
+fi
+
 dnl ipv4 only option
 AC_SUBST([WITH_IPV6])
 AC_ARG_ENABLE([ipv6],
diff --git a/src/fuser.c b/src/fuser.c
index 8f600aa..bef14e2 100644
--- a/src/fuser.c
+++ b/src/fuser.c
@@ -106,7 +106,11 @@ static dev_t device(const char *path);
 static char *expandpath(const char *path);
 
 typedef int (*stat_t)(const char*, struct stat*);
+#ifdef WITH_TIMEOUT_STAT
 static int timeout(stat_t func, const char *path, struct stat *buf, unsigned int seconds);
+#else
+#define timeout(func,path,buf,dummy) (func)((path),(buf))
+#endif /* WITH_TIMEOUT_STAT */
 
 static void usage(const char *errormsg)
 {
@@ -1321,12 +1325,11 @@ static struct stat *get_pidstat(const pid_t pid, const char *filename)
 	if ((st = (struct stat*)malloc(sizeof(struct stat))) == NULL)
 		return NULL;
 	snprintf(pathname, 256, "/proc/%d/%s", pid, filename);
-	if (timeout(stat, pathname, st, 5) != 0)
-		goto out;
+	if (timeout(stat, pathname, st, 5) != 0) {
+      free(st);
+	  return NULL;
+    }
 	return st;
-out:
-	free(st);
-	return NULL;
 }
 
 static void
@@ -1783,6 +1786,7 @@ sigalarm(int sig)
 		siglongjmp(jenv, 1);
 }
 
+#ifdef HAVE_TIMEOUT_STAT
 static int
 timeout(stat_t func, const char *path, struct stat *buf, unsigned int seconds)
 {
@@ -1831,6 +1835,7 @@ timeout(stat_t func, const char *path, struct stat *buf, unsigned int seconds)
 err:
 	return -1;
 }
+#endif /* HAVE_TIMEOUT_STAT */
 
 #ifdef _LISTS_H
 /*
-- 
2.50.1