--- cramfs-1.1/mkcramfs.c.orig 2005-04-13 05:55:57.000000000 -0600 +++ cramfs-1.1/mkcramfs.c 2005-04-13 16:19:57.000000000 -0600 @@ -117,6 +117,7 @@ static int opt_squash = 0; static char *opt_image = NULL; static char *opt_name = NULL; +static int swap_endian = 0; static int warn_dev, warn_gid, warn_namelen, warn_skip, warn_size, warn_uid; static const char *const memory_exhausted = "memory exhausted"; @@ -155,6 +156,7 @@ " -i file insert a file image into the filesystem (requires >= 2.4.0)\n" " -n name set name of cramfs filesystem\n" " -p pad by %d bytes for boot code\n" + " -r reverse endian-ness of filesystem\n" " -s sort directory entries (old option, ignored)\n" " -v be more verbose\n" " -z make explicit holes (requires >= 2.3.39)\n" @@ -504,6 +506,50 @@ return totalsize; } +/* routines to swap endianness/bitfields in inode/superblock block data */ +static void fix_inode(struct cramfs_inode *inode) +{ +#define wswap(x) (((x)>>24) | (((x)>>8)&0xff00) | (((x)&0xff00)<<8) | (((x)&0xff)<<24)) + /* attempt #2 */ + inode->mode = (inode->mode >> 8) | ((inode->mode&0xff)<<8); + inode->uid = (inode->uid >> 8) | ((inode->uid&0xff)<<8); + inode->size = (inode->size >> 16) | (inode->size&0xff00) | + ((inode->size&0xff)<<16); + ((u32*)inode)[2] = wswap(inode->offset | (inode->namelen<<26)); +} + +static void fix_offset(struct cramfs_inode *inode, u32 offset) +{ + u32 tmp = wswap(((u32*)inode)[2]); + ((u32*)inode)[2] = wswap((offset >> 2) | (tmp&0xfc000000)); +} + +static void fix_block_pointer(u32 *p) +{ + *p = wswap(*p); +} + +static void fix_super(struct cramfs_super *super) +{ + u32 *p = (u32*)super; + + /* fix superblock fields */ + p[0] = wswap(p[0]); /* magic */ + p[1] = wswap(p[1]); /* size */ + p[2] = wswap(p[2]); /* flags */ + p[3] = wswap(p[3]); /* future */ + + /* fix filesystem info fields */ + p = (u32*)&super->fsid; + p[0] = wswap(p[0]); /* crc */ + p[1] = wswap(p[1]); /* edition */ + p[2] = wswap(p[2]); /* blocks */ + p[3] = wswap(p[3]); /* files */ + + fix_inode(&super->root); +#undef wswap +} + /* Returns sizeof(struct cramfs_super), which includes the root inode. */ static unsigned int write_superblock(struct entry *root, char *base, int size) { @@ -539,6 +585,7 @@ super->root.gid = root->gid; super->root.size = root->size; super->root.offset = offset >> 2; + if (swap_endian) fix_super(super); return offset; } @@ -553,7 +600,10 @@ if (offset >= (1 << (2 + CRAMFS_OFFSET_WIDTH))) { error_msg_and_die("filesystem too big"); } - inode->offset = (offset >> 2); + if (swap_endian) + fix_offset(inode, offset); + else + inode->offset = (offset >> 2); } /* @@ -638,6 +688,7 @@ stack_entries++; } entry = entry->next; + if (swap_endian) fix_inode(inode); } /* @@ -734,6 +785,7 @@ } *(u32 *) (base + offset) = curr; + if (swap_endian) fix_block_pointer((u32*)(base + offset)); offset += 4; } while (size); @@ -1146,7 +1198,7 @@ progname = argv[0]; /* command line options */ - while ((c = getopt(argc, argv, "hEe:i:n:psvzD:q")) != EOF) { + while ((c = getopt(argc, argv, "hEe:i:n:prsvzD:q")) != EOF) { switch (c) { case 'h': usage(MKFS_OK); @@ -1174,6 +1226,10 @@ opt_pad = PAD_SIZE; fslen_ub += PAD_SIZE; break; + case 'r': + swap_endian = 1; + printf("Swapping filesystem endian-ness\n"); + break; case 's': /* old option, ignored */ break;