autofs-5.1.2 - increase worker thread per-thread stack size

From: Ian Kent <raven@themaw.net>

automount(8) uses a worker thread per-thread stack size of 1M which is
sufficient for its needs.

But some glibc functions (such as nscd_getgr_r()) use alloca() to allocate
working storage that can have an arbitary size. Since alloca() never fails
there is no way to check for stack overflow. This has been fixed in more
recent versions of glibc.

But for older version of glibc all that can be done by automount to avoid
this is to increase the stack size.

Signed-off-by: Ian Kent <raven@themaw.net>
---
 CHANGELOG          |    1 +
 daemon/automount.c |   14 +++++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

--- autofs-5.0.7.orig/CHANGELOG
+++ autofs-5.0.7/CHANGELOG
@@ -247,6 +247,7 @@
 - fix work around sss startup delay.
 - improve scalability of direct mount path component.
 - fix invalid reference in remount_active_mount().
+- increase worker thread per-thread stack size.
 
 25/07/2012 autofs-5.0.7
 =======================
--- autofs-5.0.7.orig/daemon/automount.c
+++ autofs-5.0.7/daemon/automount.c
@@ -81,6 +81,7 @@ static int cloexec_works = 0;
 /* Attributes for creating detached and joinable threads */
 pthread_attr_t th_attr;
 pthread_attr_t th_attr_detached;
+size_t detached_thread_stack_size = PTHREAD_STACK_MIN * 144;
 
 struct master_readmap_cond mrc = {
 	PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, 0, NULL, 0, 0, 0, 0};
@@ -2483,7 +2484,7 @@ int main(int argc, char *argv[])
 
 #ifdef _POSIX_THREAD_ATTR_STACKSIZE
 	if (pthread_attr_setstacksize(
-			&th_attr_detached, PTHREAD_STACK_MIN*64)) {
+			&th_attr_detached, detached_thread_stack_size)) {
 		logerr("%s: failed to set stack size thread attribute!",
 		       program);
 		res = write(start_pipefd[1], pst_stat, sizeof(*pst_stat));
@@ -2494,6 +2495,17 @@ int main(int argc, char *argv[])
 	}
 #endif
 
+	if (pthread_attr_getstacksize(
+			&th_attr_detached, &detached_thread_stack_size)) {
+		logerr("%s: failed to get detached thread stack size!",
+		       program);
+		res = write(start_pipefd[1], pst_stat, sizeof(*pst_stat));
+		close(start_pipefd[1]);
+		release_flag_file();
+		macro_free_global_table();
+		exit(1);
+	}
+
 	info(logging, "Starting automounter version %s, master map %s",
 		version, master_list->name);
 	info(logging, "using kernel protocol version %d.%02d",