From f73f4b3a2d7a313a6cb1667bd69205ea4b09f57c Mon Sep 17 00:00:00 2001 From: Danny Milosavljevic Date: Sun, 3 May 2020 17:29:39 +0200 Subject: [PATCH] file-systems: Fix F2FS volume name accessor. Follow-up to 23b37c3d40d497cc6f07437ab26ab10e60fb6e09. * gnu/build/file-systems.scm (bytevector-utf16-length): New procedure. (null-terminated-utf16->string): New procedure. (f2fs-superblock-volume-name): Use it. --- gnu/build/file-systems.scm | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/gnu/build/file-systems.scm b/gnu/build/file-systems.scm index bbea4c766e..4ac672d96f 100644 --- a/gnu/build/file-systems.scm +++ b/gnu/build/file-systems.scm @@ -98,6 +98,22 @@ (define (read-superblock device offset size magic?) (define null-terminated-latin1->string (cut latin1->string <> zero?)) +(define (bytevector-utf16-length bv) + "Given a bytevector BV containing a NUL-terminated UTF16-encoded string, +determine where the NUL terminator is and return its index. If there's no +NUL terminator, return the size of the bytevector." + (let ((length (bytevector-length bv))) + (let loop ((index 0)) + (if (< index length) + (if (zero? (bytevector-u16-ref bv index 'little)) + index + (loop (+ index 2))) + length)))) + +(define (null-terminated-utf16->string bv endianness) + (utf16->string (sub-bytevector bv 0 (bytevector-utf16-length bv)) + endianness)) + ;;; ;;; Ext2 file systems. @@ -377,7 +393,9 @@ (define (f2fs-superblock-uuid sblock) (define (f2fs-superblock-volume-name sblock) "Return the volume name of SBLOCK as a string of at most 512 characters, or #f if SBLOCK has no volume name." - (utf16->string (sub-bytevector sblock (- (+ #x470 12) #x400) 512) %f2fs-endianness)) + (null-terminated-utf16->string + (sub-bytevector sblock (- (+ #x470 12) #x400) 512) + %f2fs-endianness)) (define (check-f2fs-file-system device) "Return the health of a F2FS file system on DEVICE."