342 lines
8.8 KiB
C
342 lines
8.8 KiB
C
/*
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* cramfs.c
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*
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* Copyright (C) 1999 Linus Torvalds
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*
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* Copyright (C) 2000-2002 Transmeta Corporation
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*
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* Copyright (C) 2003 Kai-Uwe Bloem,
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* Auerswald GmbH & Co KG, <linux-development@auerswald.de>
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* - adapted from the www.tuxbox.org u-boot tree, added "ls" command
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License (Version 2) as
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* published by the Free Software Foundation.
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*
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* Compressed ROM filesystem for Linux.
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*
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* TODO:
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* add support for resolving symbolic links
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*/
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/*
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* These are the VFS interfaces to the compressed ROM filesystem.
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* The actual compression is based on zlib, see the other files.
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*/
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#include <common.h>
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#include <malloc.h>
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#include <asm/byteorder.h>
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#include <linux/stat.h>
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#include <jffs2/jffs2.h>
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#include <jffs2/load_kernel.h>
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#include <cramfs/cramfs_fs.h>
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/* These two macros may change in future, to provide better st_ino
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semantics. */
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#define CRAMINO(x) (CRAMFS_GET_OFFSET(x) ? CRAMFS_GET_OFFSET(x)<<2 : 1)
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#define OFFSET(x) ((x)->i_ino)
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struct cramfs_super super;
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/* CPU address space offset calculation macro, struct part_info offset is
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* device address space offset, so we need to shift it by a device start address. */
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extern flash_info_t flash_info[];
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#define PART_OFFSET(x) (x->offset + flash_info[x->dev->id->num].start[0])
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static int cramfs_read_super (struct part_info *info)
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{
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unsigned long root_offset;
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/* Read the first block and get the superblock from it */
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memcpy (&super, (void *) PART_OFFSET(info), sizeof (super));
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/* Do sanity checks on the superblock */
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if (super.magic != CRAMFS_32 (CRAMFS_MAGIC)) {
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/* check at 512 byte offset */
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memcpy (&super, (void *) PART_OFFSET(info) + 512, sizeof (super));
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if (super.magic != CRAMFS_32 (CRAMFS_MAGIC)) {
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printf ("cramfs: wrong magic\n");
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return -1;
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}
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}
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/* flags is reused several times, so swab it once */
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super.flags = CRAMFS_32 (super.flags);
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super.size = CRAMFS_32 (super.size);
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/* get feature flags first */
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if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) {
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printf ("cramfs: unsupported filesystem features\n");
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return -1;
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}
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/* Check that the root inode is in a sane state */
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if (!S_ISDIR (CRAMFS_16 (super.root.mode))) {
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printf ("cramfs: root is not a directory\n");
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return -1;
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}
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root_offset = CRAMFS_GET_OFFSET (&(super.root)) << 2;
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if (root_offset == 0) {
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printf ("cramfs: empty filesystem");
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} else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
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((root_offset != sizeof (struct cramfs_super)) &&
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(root_offset != 512 + sizeof (struct cramfs_super)))) {
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printf ("cramfs: bad root offset %lu\n", root_offset);
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return -1;
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}
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return 0;
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}
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static unsigned long cramfs_resolve (unsigned long begin, unsigned long offset,
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unsigned long size, int raw,
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char *filename)
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{
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unsigned long inodeoffset = 0, nextoffset;
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while (inodeoffset < size) {
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struct cramfs_inode *inode;
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char *name;
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int namelen;
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inode = (struct cramfs_inode *) (begin + offset +
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inodeoffset);
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/*
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* Namelengths on disk are shifted by two
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* and the name padded out to 4-byte boundaries
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* with zeroes.
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*/
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namelen = CRAMFS_GET_NAMELEN (inode) << 2;
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name = (char *) inode + sizeof (struct cramfs_inode);
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nextoffset =
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inodeoffset + sizeof (struct cramfs_inode) + namelen;
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for (;;) {
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if (!namelen)
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return -1;
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if (name[namelen - 1])
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break;
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namelen--;
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}
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if (!strncmp (filename, name, namelen)) {
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char *p = strtok (NULL, "/");
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if (raw && (p == NULL || *p == '\0'))
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return offset + inodeoffset;
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if (S_ISDIR (CRAMFS_16 (inode->mode))) {
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return cramfs_resolve (begin,
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CRAMFS_GET_OFFSET
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(inode) << 2,
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CRAMFS_24 (inode->
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size), raw,
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p);
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} else if (S_ISREG (CRAMFS_16 (inode->mode))) {
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return offset + inodeoffset;
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} else {
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printf ("%*.*s: unsupported file type (%x)\n",
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namelen, namelen, name,
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CRAMFS_16 (inode->mode));
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return 0;
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}
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}
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inodeoffset = nextoffset;
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}
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printf ("can't find corresponding entry\n");
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return 0;
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}
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static int cramfs_uncompress (unsigned long begin, unsigned long offset,
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unsigned long loadoffset)
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{
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struct cramfs_inode *inode = (struct cramfs_inode *) (begin + offset);
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unsigned long *block_ptrs = (unsigned long *)
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(begin + (CRAMFS_GET_OFFSET (inode) << 2));
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unsigned long curr_block = (CRAMFS_GET_OFFSET (inode) +
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(((CRAMFS_24 (inode->size)) +
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4095) >> 12)) << 2;
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int size, total_size = 0;
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int i;
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cramfs_uncompress_init ();
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for (i = 0; i < ((CRAMFS_24 (inode->size) + 4095) >> 12); i++) {
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size = cramfs_uncompress_block ((void *) loadoffset,
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(void *) (begin + curr_block),
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(CRAMFS_32 (block_ptrs[i]) -
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curr_block));
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if (size < 0)
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return size;
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loadoffset += size;
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total_size += size;
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curr_block = CRAMFS_32 (block_ptrs[i]);
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}
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cramfs_uncompress_exit ();
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return total_size;
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}
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int cramfs_load (char *loadoffset, struct part_info *info, char *filename)
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{
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unsigned long offset;
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if (cramfs_read_super (info))
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return -1;
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offset = cramfs_resolve (PART_OFFSET(info),
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CRAMFS_GET_OFFSET (&(super.root)) << 2,
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CRAMFS_24 (super.root.size), 0,
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strtok (filename, "/"));
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if (offset <= 0)
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return offset;
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return cramfs_uncompress (PART_OFFSET(info), offset,
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(unsigned long) loadoffset);
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}
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static int cramfs_list_inode (struct part_info *info, unsigned long offset)
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{
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struct cramfs_inode *inode = (struct cramfs_inode *)
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(PART_OFFSET(info) + offset);
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char *name, str[20];
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int namelen, nextoff;
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/*
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* Namelengths on disk are shifted by two
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* and the name padded out to 4-byte boundaries
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* with zeroes.
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*/
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namelen = CRAMFS_GET_NAMELEN (inode) << 2;
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name = (char *) inode + sizeof (struct cramfs_inode);
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nextoff = namelen;
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for (;;) {
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if (!namelen)
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return namelen;
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if (name[namelen - 1])
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break;
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namelen--;
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}
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printf (" %s %8d %*.*s", mkmodestr (CRAMFS_16 (inode->mode), str),
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CRAMFS_24 (inode->size), namelen, namelen, name);
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if ((CRAMFS_16 (inode->mode) & S_IFMT) == S_IFLNK) {
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/* symbolic link.
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* Unpack the link target, trusting in the inode's size field.
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*/
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unsigned long size = CRAMFS_24 (inode->size);
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char *link = malloc (size);
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if (link != NULL && cramfs_uncompress (PART_OFFSET(info), offset,
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(unsigned long) link)
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== size)
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printf (" -> %*.*s\n", (int) size, (int) size, link);
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else
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printf (" [Error reading link]\n");
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if (link)
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free (link);
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} else
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printf ("\n");
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return nextoff;
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}
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int cramfs_ls (struct part_info *info, char *filename)
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{
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struct cramfs_inode *inode;
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unsigned long inodeoffset = 0, nextoffset;
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unsigned long offset, size;
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if (cramfs_read_super (info))
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return -1;
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if (strlen (filename) == 0 || !strcmp (filename, "/")) {
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/* Root directory. Use root inode in super block */
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offset = CRAMFS_GET_OFFSET (&(super.root)) << 2;
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size = CRAMFS_24 (super.root.size);
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} else {
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/* Resolve the path */
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offset = cramfs_resolve (PART_OFFSET(info),
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CRAMFS_GET_OFFSET (&(super.root)) <<
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2, CRAMFS_24 (super.root.size), 1,
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strtok (filename, "/"));
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if (offset <= 0)
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return offset;
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/* Resolving was successful. Examine the inode */
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inode = (struct cramfs_inode *) (PART_OFFSET(info) + offset);
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if (!S_ISDIR (CRAMFS_16 (inode->mode))) {
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/* It's not a directory - list it, and that's that */
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return (cramfs_list_inode (info, offset) > 0);
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}
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/* It's a directory. List files within */
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offset = CRAMFS_GET_OFFSET (inode) << 2;
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size = CRAMFS_24 (inode->size);
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}
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/* List the given directory */
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while (inodeoffset < size) {
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inode = (struct cramfs_inode *) (PART_OFFSET(info) + offset +
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inodeoffset);
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nextoffset = cramfs_list_inode (info, offset + inodeoffset);
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if (nextoffset == 0)
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break;
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inodeoffset += sizeof (struct cramfs_inode) + nextoffset;
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}
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return 1;
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}
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int cramfs_info (struct part_info *info)
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{
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if (cramfs_read_super (info))
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return 0;
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printf ("size: 0x%x (%u)\n", super.size, super.size);
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if (super.flags != 0) {
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printf ("flags:\n");
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if (super.flags & CRAMFS_FLAG_FSID_VERSION_2)
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printf ("\tFSID version 2\n");
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if (super.flags & CRAMFS_FLAG_SORTED_DIRS)
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printf ("\tsorted dirs\n");
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if (super.flags & CRAMFS_FLAG_HOLES)
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printf ("\tholes\n");
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if (super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET)
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printf ("\tshifted root offset\n");
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}
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printf ("fsid:\n\tcrc: 0x%x\n\tedition: 0x%x\n",
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super.fsid.crc, super.fsid.edition);
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printf ("name: %16s\n", super.name);
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return 1;
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}
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int cramfs_check (struct part_info *info)
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{
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struct cramfs_super *sb;
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if (info->dev->id->type != MTD_DEV_TYPE_NOR)
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return 0;
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sb = (struct cramfs_super *) PART_OFFSET(info);
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if (sb->magic != CRAMFS_32 (CRAMFS_MAGIC)) {
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/* check at 512 byte offset */
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sb = (struct cramfs_super *) (PART_OFFSET(info) + 512);
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if (sb->magic != CRAMFS_32 (CRAMFS_MAGIC))
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return 0;
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}
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return 1;
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}
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