X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=extras%2Fvolume_id%2Flib%2Ffat.c;h=c0cfed82c008ccfd9d18c3a37f466f45ea7abbcf;hb=387a8271207b4e921258194cf359039babbc33b9;hp=e30318cf0967477e5931c58efd7dee6252fce42c;hpb=3e39ff63658ed76398d0ee98f361221744fe591f;p=elogind.git

diff --git a/extras/volume_id/lib/fat.c b/extras/volume_id/lib/fat.c
index e30318cf0..c0cfed82c 100644
--- a/extras/volume_id/lib/fat.c
+++ b/extras/volume_id/lib/fat.c
@@ -411,7 +411,11 @@ magic:
 
 fat32:
 	info("looking for FAT32\n");
-	/* FAT32 should have a valid signature in the fsinfo block */
+	/*
+	 * FAT32 should have a valid signature in the fsinfo block,
+	 * but also allow all bytes set to '\0', because some volumes
+	 * do not set the signature at all.
+	 */
 	fsinfo_sect = le16_to_cpu(vs->type.fat32.fsinfo_sector);
 	buf = volume_id_get_buffer(id, off + (fsinfo_sect * sector_size), 0x200);
 	if (buf == NULL)
@@ -423,11 +427,13 @@ fat32:
 	info("signature2: 0x%02x%02x%02x%02x\n",
 	     fsinfo->signature2[0], fsinfo->signature2[1],
 	     fsinfo->signature2[2], fsinfo->signature2[3]);
-	if (memcmp(fsinfo->signature1, "\x52\x52\x61\x41", 4) != 0)
+	if (memcmp(fsinfo->signature1, "\x52\x52\x61\x41", 4) != 0 &&
+	    memcmp(fsinfo->signature1, "\x00\x00\x00\x00", 4) != 0)
 		return -1;
-	if (memcmp(fsinfo->signature2, "\x72\x72\x41\x61", 4) != 0)
+	if (memcmp(fsinfo->signature2, "\x72\x72\x41\x61", 4) != 0 &&
+	    memcmp(fsinfo->signature2, "\x00\x00\x00\x00", 4) != 0)
 		return -1 ;
-	info("FAT32 signatures match\n");
+	info("FAT32 signatures ok\n");
 
 	vs = (struct vfat_super_block *) volume_id_get_buffer(id, off, 0x200);
 	if (vs == NULL)
@@ -497,6 +503,7 @@ fat32:
 found:
 	volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 	id->type = "vfat";
-
+	/* we think this is fat, but we make sure no other signatures are found */
+	id->force_unique_result = 1;
 	return 0;
 }