diff options
Diffstat (limited to 'guix/build/linux-initrd.scm')
| -rw-r--r-- | guix/build/linux-initrd.scm | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/guix/build/linux-initrd.scm b/guix/build/linux-initrd.scm index 627c55f865..7778c2ca97 100644 --- a/guix/build/linux-initrd.scm +++ b/guix/build/linux-initrd.scm @@ -116,14 +116,25 @@ if DEVICE does not contain an ext2 file system." ;; The magic bytes that identify an ext2 file system. #xef53) + (define superblock-size + ;; Size of the interesting part of an ext2 superblock. + 264) + + (define block + ;; The superblock contents. + (make-bytevector superblock-size)) + (call-with-input-file device (lambda (port) (seek port 1024 SEEK_SET) - (let* ((block (get-bytevector-n port 264)) - (magic (bytevector-u16-ref block %ext2-sblock-magic - %ext2-endianness))) - (and (= magic %ext2-magic) - block))))) + + ;; Note: work around <http://bugs.gnu.org/17466>. + (and (eqv? superblock-size (get-bytevector-n! port block 0 + superblock-size)) + (let ((magic (bytevector-u16-ref block %ext2-sblock-magic + %ext2-endianness))) + (and (= magic %ext2-magic) + block)))))) (define (ext2-superblock-uuid sblock) "Return the UUID of ext2 superblock SBLOCK as a 16-byte bytevector." |