diff options
Diffstat (limited to 'utils/astcanary.c')
| -rw-r--r-- | utils/astcanary.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/utils/astcanary.c b/utils/astcanary.c index aa13c5656..bcf2abb69 100644 --- a/utils/astcanary.c +++ b/utils/astcanary.c @@ -87,9 +87,25 @@ static const char explanation[] = int main(int argc, char *argv[]) { int fd; + pid_t parent; + + if (argc < 3) { + fprintf(stderr, "Usage: %s <monitor-filename> <ppid>\n", argv[0]); + exit(1); + } + /* Run at normal priority */ setpriority(PRIO_PROCESS, 0, 0); - for (;;) { + + /*!\note + * See http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#tag_03_265 + * for a justification of this approach. The PPID after the creator dies in Linux and + * most other Unix-like systems will be 1, but this is not strictly the case. The POSIX + * specification allows it to be an implementation-defined system process. However, it + * most certainly will not be the original parent PID, which makes the following code + * POSIX-compliant. + */ + for (parent = atoi(argv[2]); parent == getppid() ;) { /* Update the modification times (checked from Asterisk) */ if (utime(argv[1], NULL)) { /* Recreate the file if it doesn't exist */ @@ -108,7 +124,7 @@ int main(int argc, char *argv[]) sleep(5); } - /* Never reached */ + /* Exit when the parent dies */ return 0; } |