Patch for getroot.c

[Seth Goldberg]

Hi,

  When testing with UMEM_DEBUG set to default on Solaris, I discovered that 
find_root_device_from_libzfs() was maintaining a pointer to state that was 
freed when zpool_close() was called (specifically, the device path string, 
retrieved from an nvlist).  The path here fixes that and make this function a 
bit more bulletproof by testing for NULLs.  (Note that this returns memory 
that is not freed by the util programs that use it, but that's not unique to 
this patch -- all strings from grub_guess_root_device() aren't freed after 
they're used.)

=== modified file 'grub-core/kern/emu/getroot.c'
--- grub-core/kern/emu/getroot.c        2011-01-12 02:57:53 +0000
+++ grub-core/kern/emu/getroot.c        2011-02-11 19:48:23 +0000
@@ -185,7 +185,7 @@
 static char *
 find_root_device_from_libzfs (const char *dir, struct stat *sbp)
 {
-  char *device;
+  char *device = NULL;
   char *poolname;
   char *poolfs;

@@ -224,9 +224,13 @@
        if (nvlist_lookup_string (children[i], "path", &device) != 0)
          error (1, errno, "nvlist_lookup_string (\"path\")");

+        grub_dprintf("zfs", "device -> %s\n", device);
+
        struct stat st;
-       if (stat (device, &st) == 0)
+       if (stat (device, &st) == 0) {
+          device = grub_strdup(device);
          break;
+        }

        device = NULL;
       }
@@ -240,12 +244,15 @@

 #if defined(__sun__)
   /* If the device is a /dev/dsk path, convert it into a /dev/rdsk one */
-  if (strncmp(device, "/dev/dsk/", 9) == 0) {
-    device = xasprintf("/dev/rdsk/%s", device + 9);
+  if (device != NULL && strncmp(device, "/dev/dsk/", 9) == 0) {
+    char *newdevice = xasprintf("/dev/rdsk/%s", device + 9);
+    grub_free(device);
+    device = newdevice;
   }
 #endif

-  grub_util_info("zfs path = %s", device);
+  if (device != NULL)
+    grub_util_info("zfs path = %s", device);

   return device;
 }