Make more robust (patch by Larry Doolittle).

git-svn-id: svn://busybox.net/trunk/busybox@2712 69ca8d6d-28ef-0310-b511-8ec308f3f277

1 files changed, 11 insertions, 5 deletions

diff --git a/libbb/find_root_device.c b/libbb/find_root_device.c
index 75ed1a979..edfd7085a 100644
--- a/libbb/find_root_device.c
+++ b/libbb/find_root_device.c
@@ -39,16 +39,18 @@ extern char *find_real_root_device_name(const char* name)
         struct dirent *entry;
         struct stat statBuf, rootStat;
         char *fileName;
+        dev_t dev;
 
         if (stat("/", &rootStat) != 0) {
-                error_msg("could not stat '/'");
+                perror_msg("could not stat '/'");
                 return NULL;
         }
+        if ((dev = rootStat.st_rdev)==0) dev=rootStat.st_dev;
 
         dir = opendir("/dev");
         if (!dir) {
-                error_msg("could not open '/dev'");
-                return NULL;
+                perror_msg("could not open '/dev'");
+                goto fallback;
         }
 
         while((entry = readdir(dir)) != NULL) {
@@ -64,14 +66,18 @@ extern char *find_real_root_device_name(const char* name)
                  * devices, so make sure this is a block device */
                 if (stat(fileName, &statBuf) == 0 && 
                                 S_ISBLK(statBuf.st_mode)!=0 &&
-                                statBuf.st_rdev == rootStat.st_rdev) {
+                                statBuf.st_rdev == dev) {
                         return fileName; 
                 }
                 free(fileName);
         }
         closedir(dir);
 
-        return NULL;
+fallback:
+        /* don't use stack space, caller expects to free() result */
+        fileName=xmalloc(20);
+        sprintf(fileName,"(rdev %u)",(unsigned int) rootStat.st_rdev);
+        return fileName;
 }