diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/vvfat.c | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/block/vvfat.c b/block/vvfat.c index f9bf840..e76b42d 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -2993,11 +2993,35 @@ DLOG(checkpoint()); vvfat_close_current_file(s); + if (sector_num == s->offset_to_bootsector && nb_sectors == 1) { + /* + * Write on bootsector. Allow only changing the reserved1 field, + * used to mark volume dirtiness + */ + unsigned char *bootsector = s->first_sectors + + s->offset_to_bootsector * 0x200; + /* + * LATER TODO: if FAT32, this is wrong (see init_directories(), + * which always creates a FAT16 bootsector) + */ + const int reserved1_offset = offsetof(bootsector_t, u.fat16.reserved1); + + for (i = 0; i < 0x200; i++) { + if (i != reserved1_offset && bootsector[i] != buf[i]) { + fprintf(stderr, "Tried to write to protected bootsector\n"); + return -1; + } + } + + /* Update bootsector with the only updatable byte, and return success */ + bootsector[reserved1_offset] = buf[reserved1_offset]; + return 0; + } + /* * Some sanity checks: * - do not allow writing to the boot sector */ - if (sector_num < s->offset_to_fat) return -1; |