cramfs

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+/*
+ * cramfs.c
+ *
+ * Copyright (C) 1999 Linus Torvalds
+ *
+ * Copyright (C) 2000-2002 Transmeta Corporation
+ *
+ * Copyright (C) 2003 Kai-Uwe Bloem,
+ * Auerswald GmbH & Co KG, <[email protected]>
+ * - adapted from the www.tuxbox.org u-boot tree, added "ls" command
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * Compressed ROM filesystem for Linux.
+ *
+ * TODO:
+ * add support for resolving symbolic links
+ */
+
+/*
+ * These are the VFS interfaces to the compressed ROM filesystem.
+ * The actual compression is based on zlib, see the other files.
+ */
+
+#include <common.h>
+#include <malloc.h>
+
+#if (CONFIG_COMMANDS & CFG_CMD_JFFS2)
+
+#include <asm/byteorder.h>
+#include <linux/stat.h>
+#include <jffs2/load_kernel.h>
+#include "cramfs_fs.h"
+
+/* These two macros may change in future, to provide better st_ino
+   semantics. */
+#define CRAMINO(x)	(CRAMFS_GET_OFFSET(x) ? CRAMFS_GET_OFFSET(x)<<2 : 1)
+#define OFFSET(x)	((x)->i_ino)
+
+struct cramfs_super super;
+
+static int cramfs_read_super (struct part_info *info)
+{
+	unsigned long root_offset;
+
+	/* Read the first block and get the superblock from it */
+	memcpy (&super, (void *) info->offset, sizeof(super));
+
+	/* Do sanity checks on the superblock */
+	if (super.magic != CRAMFS_32 (CRAMFS_MAGIC)) {
+		/* check at 512 byte offset */
+		memcpy (&super, (void *) info->offset + 512, sizeof(super));
+		if (super.magic != CRAMFS_32 (CRAMFS_MAGIC)) {
+			printf ("cramfs: wrong magic\n");
+			return -1;
+		}
+	}
+
+	/* flags is reused several times, so swab it once */
+	super.flags = CRAMFS_32 (super.flags);
+	super.size = CRAMFS_32 (super.size);
+
+	/* get feature flags first */
+	if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) {
+		printf ("cramfs: unsupported filesystem features\n");
+		return -1;
+	}
+
+	/* Check that the root inode is in a sane state */
+	if (!S_ISDIR (CRAMFS_16 (super.root.mode))) {
+		printf ("cramfs: root is not a directory\n");
+		return -1;
+	}
+	root_offset = CRAMFS_GET_OFFSET (&(super.root)) << 2;
+	if (root_offset == 0)
+		printf ("cramfs: empty filesystem");
+	else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
+		 ((root_offset != sizeof (struct cramfs_super)) &&
+		  (root_offset != 512 + sizeof (struct cramfs_super))))
+	{
+		printf ("cramfs: bad root offset %lu\n", root_offset);
+		return -1;
+	}
+
+	return 0;
+}
+
+static unsigned long cramfs_resolve (char *begin, unsigned long offset,
+		unsigned long size, int raw, char *filename)
+{
+	unsigned long inodeoffset = 0, nextoffset;
+
+	while (inodeoffset < size) {
+		struct cramfs_inode *inode;
+		char *name;
+		int namelen;
+
+		inode = (struct cramfs_inode *) (begin + offset + inodeoffset);
+
+		/*
+		 * Namelengths on disk are shifted by two
+		 * and the name padded out to 4-byte boundaries
+		 * with zeroes.
+		 */
+		namelen = CRAMFS_GET_NAMELEN(inode) << 2;
+		name = (char *) inode + sizeof (struct cramfs_inode);
+
+		nextoffset = inodeoffset + sizeof (struct cramfs_inode) + namelen;
+
+		for (;;) {
+			if (!namelen)
+				return -1;
+			if (name[namelen-1])
+				break;
+			namelen--;
+		}
+
+		if (!strncmp (filename, name, namelen))
+		{
+			char *p = strtok (NULL, "/");
+			if (raw && (p == NULL || *p == '\0'))
+				return offset + inodeoffset;
+
+			if (S_ISDIR (CRAMFS_16 (inode->mode)))
+			{
+				return cramfs_resolve (begin,
+					CRAMFS_GET_OFFSET(inode) << 2,
+					CRAMFS_24(inode->size), raw, p);
+			}
+			else if (S_ISREG (CRAMFS_16 (inode->mode)))
+			{
+				return offset + inodeoffset;
+			}
+			else
+			{
+				printf ("%*.*s: unsupported file type (%x)\n",
+					namelen, namelen, name,
+					CRAMFS_16 (inode->mode));
+				return 0;
+			}
+		}
+
+		inodeoffset = nextoffset;
+	}
+
+	printf ("can't find corresponding entry\n");
+	return 0;
+}
+
+static int cramfs_uncompress (char * begin, unsigned long offset,
+		unsigned long loadoffset)
+{
+	struct cramfs_inode *inode = (struct cramfs_inode *) (begin + offset);
+	unsigned long *block_ptrs = (unsigned long *)
+			(begin + (CRAMFS_GET_OFFSET (inode) << 2));
+	unsigned long curr_block = (CRAMFS_GET_OFFSET (inode) +
+			(((CRAMFS_24 (inode->size)) + 4095) >> 12)) << 2;
+	int size, total_size = 0;
+	int i;
+
+	cramfs_uncompress_init ();
+
+	for (i = 0; i < ((CRAMFS_24(inode->size) + 4095) >> 12); i++)
+       	{
+		size = cramfs_uncompress_block ((void *) loadoffset,
+				(void *) (begin + curr_block),
+				(CRAMFS_32 (block_ptrs[i]) - curr_block));
+		if (size < 0)
+		       return size;
+		loadoffset += size;
+		total_size += size;
+		curr_block = CRAMFS_32 (block_ptrs[i]);
+	}
+
+	cramfs_uncompress_exit ();
+	return total_size;
+}
+
+int cramfs_load (char *loadoffset, struct part_info *info, char *filename)
+{
+	unsigned long offset;
+
+	if (cramfs_read_super (info))
+		return -1;
+
+	offset = cramfs_resolve (info->offset,
+			CRAMFS_GET_OFFSET(&(super.root)) << 2,
+			CRAMFS_24(super.root.size), 0, strtok (filename, "/"));
+
+	if (offset <= 0)
+		return offset;
+
+	return cramfs_uncompress (info->offset, offset,
+			(unsigned long) loadoffset);
+}
+
+static char *mkmodestr(unsigned long mode, char *str)
+{
+	static const char *l = "xwr";
+	int mask = 1, i;
+	char c;
+
+	switch (mode & S_IFMT) {
+		case S_IFDIR:    str[0] = 'd'; break;
+		case S_IFBLK:    str[0] = 'b'; break;
+		case S_IFCHR:    str[0] = 'c'; break;
+		case S_IFIFO:    str[0] = 'f'; break;
+		case S_IFLNK:    str[0] = 'l'; break;
+		case S_IFSOCK:   str[0] = 's'; break;
+		case S_IFREG:    str[0] = '-'; break;
+		default:         str[0] = '?';
+	}
+
+	for(i = 0; i < 9; i++) {
+		c = l[i%3];
+		str[9-i] = (mode & mask)?c:'-';
+		mask = mask<<1;
+	}
+
+	if(mode & S_ISUID) str[3] = (mode & S_IXUSR)?'s':'S';
+	if(mode & S_ISGID) str[6] = (mode & S_IXGRP)?'s':'S';
+	if(mode & S_ISVTX) str[9] = (mode & S_IXOTH)?'t':'T';
+	str[10] = '\0';
+	return str;
+}
+
+static int cramfs_list_inode(struct part_info *info, unsigned long offset)
+{
+	struct cramfs_inode *inode = (struct cramfs_inode *)
+			(info->offset + offset);
+	char *name, str[20];
+	int namelen, nextoff;
+
+	/*
+ 	 * Namelengths on disk are shifted by two
+ 	 * and the name padded out to 4-byte boundaries
+ 	 * with zeroes.
+ 	 */
+	namelen = CRAMFS_GET_NAMELEN(inode) << 2;
+	name = (char *) inode + sizeof (struct cramfs_inode);
+	nextoff = namelen;
+
+	for (;;) {
+		if (!namelen)
+			return namelen;
+		if (name[namelen-1])
+			break;
+		namelen--;
+	}
+
+	printf(" %s %8d %*.*s", mkmodestr(CRAMFS_16 (inode->mode),str),
+			 CRAMFS_24(inode->size), namelen, namelen, name);
+
+	if ((CRAMFS_16 (inode->mode) & S_IFMT) == S_IFLNK) {
+		/* symbolic link.
+		 * Unpack the link target, trusting in the inode's size field.
+		 */
+		unsigned long size = CRAMFS_24 (inode->size);
+		char *link = malloc(size);
+		if (link != NULL && cramfs_uncompress(info->offset, offset,
+					(unsigned long)link) == size)
+			printf(" -> %*.*s\n", (int)size, (int)size, link);
+		else
+			printf(" [Error reading link]\n");
+		if (link) free (link);
+	} else
+		printf("\n");
+
+	return nextoff;
+}
+
+int cramfs_ls (struct part_info *info, char *filename)
+{
+	struct cramfs_inode *inode;
+	unsigned long inodeoffset = 0, nextoffset;
+	unsigned long offset, size;
+
+	if (cramfs_read_super (info))
+		return -1;
+
+	if (strlen(filename) == 0 || !strcmp(filename, "/")) {
+		/* Root directory. Use root inode in super block */
+		offset = CRAMFS_GET_OFFSET(&(super.root)) << 2;
+		size = CRAMFS_24(super.root.size);
+	} else {
+		/* Resolve the path */
+		offset = cramfs_resolve (info->offset,
+				CRAMFS_GET_OFFSET(&(super.root)) << 2,
+				CRAMFS_24(super.root.size), 1, strtok (filename, "/"));
+
+		if (offset <= 0)
+			return offset;
+
+		/* Resolving was successful. Examine the inode */
+		inode = (struct cramfs_inode *) (info->offset + offset);
+		if (! S_ISDIR (CRAMFS_16 (inode->mode))) {
+			/* It's not a directory - list it, and that's that */
+			return (cramfs_list_inode(info, offset) > 0);
+		}
+
+		/* It's a directory. List files within */
+		offset = CRAMFS_GET_OFFSET(inode) << 2;
+		size = CRAMFS_24(inode->size);
+	}
+
+	/* List the given directory */
+	while (inodeoffset < size) {
+		inode = (struct cramfs_inode *) (info->offset + offset + inodeoffset);
+
+		nextoffset = cramfs_list_inode(info, offset + inodeoffset);
+		if (nextoffset == 0)
+			break;
+		inodeoffset += sizeof (struct cramfs_inode) + nextoffset;
+	}
+
+	return 1;
+}
+
+int cramfs_info (struct part_info *info)
+{
+	if (cramfs_read_super (info))
+		return 0;
+
+	printf ("size: 0x%x (%u)\n", super.size, super.size);
+
+	if (super.flags != 0)
+	{
+		printf ("flags:\n");
+		if (super.flags & CRAMFS_FLAG_FSID_VERSION_2)
+			printf ("\tFSID version 2\n");
+		if (super.flags & CRAMFS_FLAG_SORTED_DIRS)
+			printf ("\tsorted dirs\n");
+		if (super.flags & CRAMFS_FLAG_HOLES)
+			printf ("\tholes\n");
+		if (super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET)
+			printf ("\tshifted root offset\n");
+	}
+
+	printf ("fsid:\n\tcrc: 0x%x\n\tedition: 0x%x\n",
+			super.fsid.crc, super.fsid.edition);
+	printf ("name: %16s\n", super.name);
+
+	return 1;
+}
+
+int cramfs_check (struct part_info *info)
+{
+	struct cramfs_super *sb = (struct cramfs_super *)info->offset;
+
+	if (sb->magic != CRAMFS_32 (CRAMFS_MAGIC)) {
+		/* check at 512 byte offset */
+		sb = (struct cramfs_super *)(info->offset + 512);
+		if (sb->magic != CRAMFS_32 (CRAMFS_MAGIC)) {
+			return 0;
+		}
+	}
+	return 1;
+}
+
+#endif /* CFG_FS_CRAMFS */

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+#ifndef _CRAMFS_FS_SB
+#define _CRAMFS_FS_SB
+
+/*
+ * cramfs super-block data in memory
+ */
+struct cramfs_sb_info {
+			unsigned long magic;
+			unsigned long size;
+			unsigned long blocks;
+			unsigned long files;
+			unsigned long flags;
+#ifdef CONFIG_CRAMFS_LINEAR
+			unsigned long linear_phys_addr;
+			char *        linear_virt_addr;
+#endif
+};
+
+#endif

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@@ -106,8 +106,8 @@
  *
  * You still should have paper bags at hand :-(. The code lacks more or less
  * any comment, and is still arcane and difficult to read in places. As this
- * is incompatible with any new code from the jffs2 maintainers anyway, it
- * should probably be dumped and replaced by something like jffs2reader!
+ * might be incompatible with any new code from the jffs2 maintainers anyway,
+ * it should probably be dumped and replaced by something like jffs2reader!
  */