diff options
author | tilghman <tilghman@f38db490-d61c-443f-a65b-d21fe96a405b> | 2007-12-18 23:06:05 +0000 |
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committer | tilghman <tilghman@f38db490-d61c-443f-a65b-d21fe96a405b> | 2007-12-18 23:06:05 +0000 |
commit | 11a5516081314ebee69ff72fa76d3fbf554c0488 (patch) | |
tree | dc6fe6d88013e7f3321d1468c36650a90fc0a2b8 /utils | |
parent | f3230e3b5b2f9d81b59764085ca39988843cd6dd (diff) |
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)
git-svn-id: http://svn.digium.com/svn/asterisk/trunk@93804 f38db490-d61c-443f-a65b-d21fe96a405b
Diffstat (limited to 'utils')
-rw-r--r-- | utils/Makefile | 2 | ||||
-rw-r--r-- | utils/astcanary.c | 84 |
2 files changed, 85 insertions, 1 deletions
diff --git a/utils/Makefile b/utils/Makefile index 6cbd39818..4c6bb1114 100644 --- a/utils/Makefile +++ b/utils/Makefile @@ -17,7 +17,7 @@ ASTTOPDIR?=.. .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 diff --git a/utils/astcanary.c b/utils/astcanary.c new file mode 100644 index 000000000..eb9f17208 --- /dev/null +++ b/utils/astcanary.c @@ -0,0 +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; +} + |