watchdogd stat location

[mike tancsa]

On 9/27/2019 3:53 PM, Warner Losh wrote:
> >
>
>     I am all for that too. Just something other than /etc or /var
>     which are
>     often mounted on ramdisk.
>
>
> I think that / is too special to cause disk IO to ever happen. Other
> dirs will sometimes not be in the cache.... The notion here, perhaps
> bogus, is that we want to check the root FS is sane. The stat(2) is a
> cheap way to do this that will eventually fail if / goes wonky enough.
> It's weak.
>
>
Would something like this buy any extra sanity ? or not worth it. I
guess fancier checks belong in a passed program


# diff -u watchdogd.c.orig watchdogd.c
--- watchdogd.c.orig    2019-09-27 16:27:14.456973000 -0400
+++ watchdogd.c 2019-09-27 16:27:18.904885000 -0400
@@ -364,9 +364,23 @@
 
                if (test_cmd != NULL)
                        failed = system(test_cmd);
-               else
-                       failed = stat("/etc", &sb);
-
+               else {
+
+                       srand(time(NULL));
+                       switch(rand() % 4) {
+                               case 0:
+                                       failed = stat("/", &sb);
+                                       break;
+                               case 1:
+                                       failed = stat("/bin", &sb);
+                                       break;
+                               case 2:
+                                       failed = stat("/sbin", &sb);
+                                       break;
+                               default:
+                                       failed = stat("/usr", &sb);
+                       }
+               }
                error = watchdog_getuptime(&ts_end);
                if (error) {
                        end_program = 1;