Add support for XFS filesystems.

diff --git a/misc/get_device_by_label.c b/misc/get_device_by_label.c
index ee5070d..6691ab3 100644 (file)
--- a/misc/get_device_by_label.c
+++ b/misc/get_device_by_label.c
@@ -48,6 +48,15 @@ struct ext2_super_block {
 };
 #define ext2magic(s)    ((unsigned int) s.s_magic[0] + (((unsigned int) s.s_magic[1]) << 8))
 
+#define XFS_SUPER_MAGIC "XFSB"
+struct xfs_super_block {
+       unsigned char   s_magic[4];
+       unsigned char   s_dummy[28];
+       unsigned char   s_uuid[16];
+       unsigned char   s_dummy2[60];
+       unsigned char   s_fname[12];
+};
+
 static struct uuidCache_s {
        struct uuidCache_s *next;
        char uuid[16];
@@ -55,34 +64,46 @@ static struct uuidCache_s {
        char *device;
 } *uuidCache = NULL;
 
-/* for now, only ext2 is supported */
+/* for now, only ext2 and xfs are supported */
 static int
 get_label_uuid(const char *device, char **label, char *uuid) {
 
-       /* start with a test for ext2, taken from mount_guess_fstype */
+       /* start with ext2 and xfs tests, taken from mount_guess_fstype */
        /* should merge these later */
        int fd;
+       size_t label_size;
+       char *sb_uuid = 0, *sb_label = 0;
        struct ext2_super_block e2sb;
+       struct xfs_super_block xfsb;
 
        fd = open(device, O_RDONLY);
        if (fd < 0)
                return 1;
 
-       if (lseek(fd, 1024, SEEK_SET) != 1024
-           || read(fd, (char *) &e2sb, sizeof(e2sb)) != sizeof(e2sb)
-           || (ext2magic(e2sb) != EXT2_SUPER_MAGIC)) {
+       if (lseek(fd, 1024, SEEK_SET) == 1024
+           && read(fd, (char *) &e2sb, sizeof(e2sb)) == sizeof(e2sb)
+           && (ext2magic(e2sb) == EXT2_SUPER_MAGIC)) {
+               sb_uuid = e2sb.s_uuid;
+               sb_label = e2sb.s_volume_name;
+               label_size = sizeof(e2sb.s_volume_name);
+       } else if (lseek(fd, 0, SEEK_SET) == 0
+           && read(fd, (char *) &xfsb, sizeof(xfsb)) == sizeof(xfsb)
+           && strncmp((char *) &xfsb.s_magic, XFS_SUPER_MAGIC, 4) == 0) {
+               sb_uuid = xfsb.s_uuid;
+               sb_label = xfsb.s_fname;
+               label_size = sizeof(xfsb.s_fname);
+       } else {
                close(fd);
                return 1;
        }
 
        close(fd);
-
-       /* superblock is ext2 - now what is its label? */
-       memcpy(uuid, e2sb.s_uuid, sizeof(e2sb.s_uuid));
-
-       *label = calloc(sizeof(e2sb.s_volume_name) + 1, 1);
-       memcpy(*label, e2sb.s_volume_name, sizeof(e2sb.s_volume_name));
-
+       if (sb_uuid)
+               memcpy(uuid, sb_uuid, sizeof(e2sb.s_uuid));
+       if (sb_label) {
+               if ((*label = calloc(label_size + 1, 1)) != NULL)
+                       memcpy(*label, sb_label, label_size);
+       }
        return 0;
 }