diff options
Diffstat (limited to 'utils/astcanary.c')
| -rw-r--r-- | utils/astcanary.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/utils/astcanary.c b/utils/astcanary.c index 495c1a604..bb3492af7 100644 --- a/utils/astcanary.c +++ b/utils/astcanary.c @@ -30,7 +30,7 @@ * 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 + * 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. * @@ -57,6 +57,18 @@ * 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. + * + * Quote: + * "The nice value set with setpriority() shall be applied to the + * process. If the process is multi-threaded, the nice value shall + * affect all system scope threads in the process." + * + * Source: + * http://www.opengroup.org/onlinepubs/000095399/functions/setpriority.html + * + * In answer to the question, what aren't system scope threads, the + * answer is, in Asterisk, nothing. Process scope threads are the + * alternative, but they aren't supported in Linux. */ const char explanation[] = @@ -77,7 +89,7 @@ int main(int argc, char *argv[]) int fd; /* Run at normal priority */ setpriority(PRIO_PROCESS, 0, 0); - for (;;) { + for (; getppid() != 1;) { /* Update the modification times (checked from Asterisk) */ if (utime(argv[1], NULL)) { /* Recreate the file if it doesn't exist */ @@ -96,7 +108,7 @@ int main(int argc, char *argv[]) sleep(5); } - /* Never reached */ + /* Reached if asterisk (our parent process) dies - its chldren are inherited by the init process (pid is 1). */ return 0; } |