diff options
Diffstat (limited to 'wd/wdd.c')
| -rw-r--r-- | wd/wdd.c | 56 |
1 files changed, 55 insertions, 1 deletions
@@ -1,5 +1,5 @@ /* - * wdd - simple watchdog daemon - 2003 - willy tarreau + * wdd - simple watchdog daemon - 2003-2004 - willy tarreau */ #include <stdio.h> @@ -10,6 +10,57 @@ const char dev_wd_str[] = "/dev/watchdog"; const char root_str[] = "/"; +/* + * This function checks if the system can allocate memory + * In case of failure, we exit so that the watchdog device + * notices it and can reboot. + */ +static inline void try_malloc() { + void *heap; + + heap = (void*)sbrk(NULL); + if (brk(heap + 4096)) + exit(1); + memset(heap, 0, 4096); + if (brk(heap)) + exit(1); +} + +/* + * This function checks if the system can fork + * In case of failure, we exit so that the watchdog device + * notices it and can reboot. + */ +static inline void try_fork() { + int pid; + pid = fork(); + if (pid < 0) /* exit on error */ + exit(1); + else if (pid == 0) /* child returns cleanly */ + exit(0); + if (waitpid(pid, NULL, 0) != pid) /* father checks child */ + exit(1); +} + + +/* + * This function checks if the system can access its root FS + * In case of failure, we exit so that the watchdog device + * notices it and can reboot. + */ +static inline void try_stat() { + void *heap; + + heap = (void*)sbrk(NULL); + if (brk(heap + sizeof (struct stat))) + exit(1); + memset(heap, 0, sizeof (struct stat)); + if (stat(root_str, heap) == -1) + exit(1); + if (brk(heap)) + exit(1); +} + int main (void) { int dev; @@ -29,6 +80,9 @@ int main (void) { close(dev); dev = -1; } + try_malloc(); + try_fork(); + try_stat(); /* avoid a fast loop */ sleep(1); } |