[asterisk-commits] tilghman: trunk r93804 - in /trunk: main/ utils/
SVN commits to the Asterisk project
asterisk-commits at lists.digium.com
Tue Dec 18 17:06:05 CST 2007
Author: tilghman
Date: Tue Dec 18 17:06:05 2007
New Revision: 93804
URL: http://svn.digium.com/view/asterisk?view=rev&rev=93804
Log:
Add a canary process, for high priority mode (asterisk -p) to ensure that if
Asterisk goes into a busy loop, the machine will be recoverable. We'd still
need to do a restart to put Asterisk back into high priority mode, but at
least a reboot won't be required. (Closes issue #11559)
Added:
trunk/utils/astcanary.c (with props)
Modified:
trunk/main/asterisk.c
trunk/utils/Makefile
Modified: trunk/main/asterisk.c
URL: http://svn.digium.com/view/asterisk/trunk/main/asterisk.c?view=diff&rev=93804&r1=93803&r2=93804
==============================================================================
--- trunk/main/asterisk.c (original)
+++ trunk/main/asterisk.c Tue Dec 18 17:06:05 2007
@@ -233,6 +233,8 @@
static int shuttingdown;
static int restartnow;
static pthread_t consolethread = AST_PTHREADT_NULL;
+static int canary_pid = 0;
+static char canary_filename[128];
static char randompool[256];
@@ -2623,6 +2625,35 @@
}
return NULL;
+}
+
+static void *canary_thread(void *unused)
+{
+ struct stat canary_stat;
+ struct timeval tv;
+
+ /* Give the canary time to sing */
+ sleep(120);
+
+ for (;;) {
+ stat(canary_filename, &canary_stat);
+ tv = ast_tvnow();
+ if (tv.tv_sec > canary_stat.st_mtime + 60) {
+ ast_log(LOG_WARNING, "Canary is dead!!! Reducing priority\n");
+ ast_set_priority(0);
+ pthread_exit(NULL);
+ }
+
+ /* Check the canary once a minute */
+ sleep(60);
+ }
+}
+
+/* Used by libc's atexit(3) function */
+static void canary_exit(void)
+{
+ if (canary_pid > 0)
+ kill(canary_pid, SIGKILL);
}
int main(int argc, char *argv[])
@@ -2808,10 +2839,49 @@
if ((!runuser) && !ast_strlen_zero(ast_config_AST_RUN_USER))
runuser = ast_config_AST_RUN_USER;
+ /* Must install this signal handler up here to ensure that if the canary
+ * fails to execute that it doesn't kill the Asterisk process.
+ */
+ signal(SIGCHLD, child_handler);
+
#ifndef __CYGWIN__
- if (isroot)
+ if (isroot) {
ast_set_priority(ast_opt_high_priority);
+ if (ast_opt_high_priority) {
+ snprintf(canary_filename, sizeof(canary_filename), "%s/alt.asterisk.canary.tweet.tweet.tweet", ast_config_AST_RUN_DIR);
+
+ canary_pid = fork();
+ if (canary_pid == 0) {
+ char canary_binary[128], *lastslash;
+ int fd;
+
+ /* Reset signal handler */
+ signal(SIGCHLD, SIG_DFL);
+
+ for (fd = 0; fd < 100; fd++)
+ close(fd);
+
+ execlp("astcanary", "astcanary", canary_filename, NULL);
+
+ /* If not found, try the same path as used to execute asterisk */
+ ast_copy_string(canary_binary, argv[0], sizeof(canary_binary));
+ if ((lastslash = strrchr(canary_binary, '/'))) {
+ ast_copy_string(lastslash + 1, "astcanary", sizeof(canary_binary) + canary_binary - (lastslash + 1));
+ execl(canary_binary, "astcanary", canary_filename, NULL);
+ }
+
+ /* Should never happen */
+ _exit(1);
+ } else if (canary_pid > 0) {
+ pthread_t dont_care;
+ ast_pthread_create_detached(&dont_care, NULL, canary_thread, NULL);
+ }
+
+ /* Kill the canary when we exit */
+ atexit(canary_exit);
+ }
+ }
if (isroot && rungroup) {
struct group *gr;
@@ -2975,7 +3045,6 @@
signal(SIGINT, __quit_handler);
signal(SIGTERM, __quit_handler);
signal(SIGHUP, hup_handler);
- signal(SIGCHLD, child_handler);
signal(SIGPIPE, SIG_IGN);
/* ensure that the random number generators are seeded with a different value every time
Modified: trunk/utils/Makefile
URL: http://svn.digium.com/view/asterisk/trunk/utils/Makefile?view=diff&rev=93804&r1=93803&r2=93804
==============================================================================
--- trunk/utils/Makefile (original)
+++ trunk/utils/Makefile Tue Dec 18 17:06:05 2007
@@ -17,7 +17,7 @@
.PHONY: clean all uninstall
# to get check_expr, add it to the ALL_UTILS list
-ALL_UTILS:=astman smsq stereorize streamplayer aelparse muted check_expr conf2ael hashtest2 hashtest
+ALL_UTILS:=astman smsq stereorize streamplayer aelparse muted check_expr conf2ael hashtest2 hashtest astcanary
UTILS:=$(ALL_UTILS)
LIBS += $(BKTR_LIB) # astobj2 with devmode uses backtrace
Added: trunk/utils/astcanary.c
URL: http://svn.digium.com/view/asterisk/trunk/utils/astcanary.c?view=auto&rev=93804
==============================================================================
--- trunk/utils/astcanary.c (added)
+++ trunk/utils/astcanary.c Tue Dec 18 17:06:05 2007
@@ -1,0 +1,84 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2007, Digium, Inc.
+ *
+ * Tilghman Lesher <tlesher AT digium DOT com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <utime.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+/*!\brief
+ * At one time, canaries were carried along with coal miners down
+ * into a mine. Their purpose was to alert the miners when they
+ * had drilled into a pocket of methane gas or another noxious
+ * substance. The canary, being the most sensitive animal would
+ * immediately fall over. Seeing this, the miners could take
+ * action to escape the mine, seeing an imminent danger.
+ *
+ * This process serves a similar purpose, though with the realtime
+ * priority being the reason. When a thread starts running away
+ * with the processor, it is typically difficult to tell what
+ * thread caused the problem, as the machine acts as if it is
+ * locked up (in fact, what has happened is that Asterisk runs at
+ * a higher priority than even the login shell, so the runaway
+ * thread hogs all available CPU time.
+ *
+ * If that happens, this canary process will cease to get any
+ * process time, which we can monitor with a realtime thread in
+ * Asterisk. Should that happen, that monitoring thread may take
+ * immediate action to slow down Asterisk to regular priority,
+ * thus allowing an administrator to login to the system and
+ * restart Asterisk or perhaps take another course of action
+ * (such as retrieving a backtrace to let the developers know
+ * what precisely went wrong).
+ *
+ * Note that according to POSIX.1, all threads inside a single
+ * process must share the same priority, so when the monitoring
+ * thread deprioritizes itself, it deprioritizes all threads at
+ * the same time. This is also why this canary must exist as a
+ * completely separate process and not simply as a thread within
+ * Asterisk itself.
+ */
+
+int main(int argc, char *argv[])
+{
+ int fd;
+ /* Run at normal priority */
+ setpriority(PRIO_PROCESS, 0, 0);
+ for (;;) {
+ /* Update the modification times (checked from Asterisk) */
+ if (utime(argv[1], NULL)) {
+ /* Recreate the file if it doesn't exist */
+ if ((fd = open(argv[1], O_RDWR | O_TRUNC | O_CREAT)) > -1)
+ close(fd);
+ else
+ exit(1);
+ continue;
+ }
+
+ /* Run occasionally */
+ sleep(5);
+ }
+
+ /* Never reached */
+ return 0;
+}
+
Propchange: trunk/utils/astcanary.c
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