From ea422a4d96dc6378f9ba715734a08097a2994f9c Mon Sep 17 00:00:00 2001
From: Tilghman Lesher <tilghman@meg.abyt.es>
Date: Wed, 19 Jan 2011 20:24:57 +0000
Subject: [PATCH] Merged revisions 302599 via svnmerge from
 https://origsvn.digium.com/svn/asterisk/branches/1.6.2

........
  r302599 | tilghman | 2011-01-19 14:13:24 -0600 (Wed, 19 Jan 2011) | 15 lines

  Kill zombies.

  When we ast_safe_fork() with a non-zero argument, we're expected to reap our
  own zombies.  On a zero argument, however, the zombies are only reaped when
  there aren't any non-zero forked children alive.  At other times, we
  accumulate zombies.  This code is forward ported from res_agi in 1.4, so that
  forked children are always reaped, thus preventing an accumulation of zombie
  processes.

  (closes issue #18515)
  Reported by: ernied
  Patches:
        20101221__issue18515.diff.txt uploaded by tilghman (license 14)
  Tested by: ernied
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@302634 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
 main/app.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 58 insertions(+), 3 deletions(-)

diff --git a/main/app.c b/main/app.c
index e6ca51483e..c0f3a6a2f6 100644
--- a/main/app.c
+++ b/main/app.c
@@ -30,10 +30,15 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #ifdef HAVE_SYS_STAT_H
 #include <sys/stat.h>
 #endif
-#include <regex.h>
-#include <sys/file.h> /* added this to allow to compile, sorry! */
-#include <signal.h>
+#include <regex.h>          /* for regcomp(3) */
+#include <sys/file.h>       /* for flock(2) */
+#include <signal.h>         /* for pthread_sigmask(3) */
 #include <stdlib.h>         /* for closefrom(3) */
+#include <sys/types.h>
+#include <sys/wait.h>       /* for waitpid(2) */
+#ifndef HAVE_CLOSEFROM
+#include <dirent.h>         /* for opendir(3)   */
+#endif
 #ifdef HAVE_CAP
 #include <sys/capability.h>
 #endif /* HAVE_CAP */
@@ -52,6 +57,41 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 
 AST_THREADSTORAGE_PUBLIC(ast_str_thread_global_buf);
 
+static pthread_t shaun_of_the_dead_thread = AST_PTHREADT_NULL;
+
+struct zombie {
+	pid_t pid;
+	AST_LIST_ENTRY(zombie) list;
+};
+
+static AST_LIST_HEAD_STATIC(zombies, zombie);
+
+static void *shaun_of_the_dead(void *data)
+{
+	struct zombie *cur;
+	int status;
+	for (;;) {
+		if (!AST_LIST_EMPTY(&zombies)) {
+			/* Don't allow cancellation while we have a lock. */
+			pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
+			AST_LIST_LOCK(&zombies);
+			AST_LIST_TRAVERSE_SAFE_BEGIN(&zombies, cur, list) {
+				if (waitpid(cur->pid, &status, WNOHANG) != 0) {
+					AST_LIST_REMOVE_CURRENT(list);
+					ast_free(cur);
+				}
+			}
+			AST_LIST_TRAVERSE_SAFE_END
+			AST_LIST_UNLOCK(&zombies);
+			pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
+		}
+		pthread_testcancel();
+		/* Wait for 60 seconds, without engaging in a busy loop. */
+		ast_poll(NULL, 0, AST_LIST_FIRST(&zombies) ? 5000 : 60000);
+	}
+	return NULL;
+}
+
 
 #define AST_MAX_FORMATS 10
 
@@ -2060,6 +2100,21 @@ int ast_safe_fork(int stop_reaper)
 	if (pid != 0) {
 		/* Fork failed or parent */
 		pthread_sigmask(SIG_SETMASK, &old_set, NULL);
+		if (!stop_reaper && pid > 0) {
+			struct zombie *cur = ast_calloc(1, sizeof(*cur));
+			if (cur) {
+				cur->pid = pid;
+				AST_LIST_LOCK(&zombies);
+				AST_LIST_INSERT_TAIL(&zombies, cur, list);
+				AST_LIST_UNLOCK(&zombies);
+				if (shaun_of_the_dead_thread == AST_PTHREADT_NULL) {
+					if (ast_pthread_create_background(&shaun_of_the_dead_thread, NULL, shaun_of_the_dead, NULL)) {
+						ast_log(LOG_ERROR, "Shaun of the Dead wants to kill zombies, but can't?!!\n");
+						shaun_of_the_dead_thread = AST_PTHREADT_NULL;
+					}
+				}
+			}
+		}
 		return pid;
 	} else {
 		/* Child */