libblkid: Make sure we never reference a null dev->bid_type

There were a few places where we don't check to make sure
dev->bid_type is non-NULL before dereferencing the pointer, mostly in
debug code.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/lib/blkid/dev.c b/lib/blkid/dev.c
index 770632b..5252a8e 100644 (file)
--- a/lib/blkid/dev.c
+++ b/lib/blkid/dev.c
@@ -34,7 +34,8 @@ void blkid_free_dev(blkid_dev dev)
                return;
 
        DBG(DEBUG_DEV,
-           printf("  freeing dev %s (%s)\n", dev->bid_name, dev->bid_type));
+           printf("  freeing dev %s (%s)\n", dev->bid_name, dev->bid_type ?
+                  dev->bid_type : "(null)"));
        DBG(DEBUG_DEV, blkid_debug_dump_dev(dev));
 
        list_del(&dev->bid_devs);

diff --git a/lib/blkid/devname.c b/lib/blkid/devname.c
index df96859..65c6cca 100644 (file)
--- a/lib/blkid/devname.c
+++ b/lib/blkid/devname.c
@@ -96,7 +96,8 @@ blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)
                        dev2 = list_entry(p, struct blkid_struct_dev, bid_devs);
                        if (dev2->bid_flags & BLKID_BID_FL_VERIFIED)
                                continue;
-                       if (strcmp(dev->bid_type, dev2->bid_type))
+                       if (!dev->bid_type || !dev2->bid_type ||
+                           strcmp(dev->bid_type, dev2->bid_type))
                                continue;
                        if (dev->bid_label && dev2->bid_label &&
                            strcmp(dev->bid_label, dev2->bid_label))

diff --git a/lib/blkid/save.c b/lib/blkid/save.c
index 76f2f9e..60aa6ce 100644 (file)
--- a/lib/blkid/save.c
+++ b/lib/blkid/save.c
@@ -34,7 +34,8 @@ static int save_dev(blkid_dev dev, FILE *file)
                return 0;
 
        DBG(DEBUG_SAVE,
-           printf("device %s, type %s\n", dev->bid_name, dev->bid_type));
+           printf("device %s, type %s\n", dev->bid_name, dev->bid_type ?
+                  dev->bid_type : "(null)"));
 
        fprintf(file,
                "<device DEVNO=\"0x%04lx\" TIME=\"%ld\"",