fs/jffs2/read.c - kernel/skids - Git at Google

 /*
  * JFFS2 -- Journalling Flash File System, Version 2.
  *
  * Copyright © 2001-2007 Red Hat, Inc.
  *
  * Created by David Woodhouse <dwmw2@infradead.org>
  *
  * For licensing information, see the file 'LICENCE' in this directory.
  *
  */

 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/crc32.h>
 #include <linux/pagemap.h>
 #include <linux/mtd/mtd.h>
 #include <linux/compiler.h>
 #include "nodelist.h"
 #include "compr.h"

 int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
 		     struct jffs2_full_dnode *fd, unsigned char *buf,
 		     int ofs, int len)
 {
 	struct jffs2_raw_inode *ri;
 	size_t readlen;
 	uint32_t crc;
 	unsigned char *decomprbuf = NULL;
 	unsigned char *readbuf = NULL;
 	int ret = 0;

 	ri = jffs2_alloc_raw_inode();
 	if (!ri)
 		return -ENOMEM;

 	ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri);
 	if (ret) {
 		jffs2_free_raw_inode(ri);
 		printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret);
 		return ret;
 	}
 	if (readlen != sizeof(*ri)) {
 		jffs2_free_raw_inode(ri);
 		printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
 		       ref_offset(fd->raw), sizeof(*ri), readlen);
 		return -EIO;
 	}
 	crc = crc32(0, ri, sizeof(*ri)-8);

 	D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
 		  ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
 		  crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
 		  je32_to_cpu(ri->offset), buf));
 	if (crc != je32_to_cpu(ri->node_crc)) {
 		printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n",
 		       je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
 		ret = -EIO;
 		goto out_ri;
 	}
 	/* There was a bug where we wrote hole nodes out with csize/dsize
 	   swapped. Deal with it */
 	if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
 	    je32_to_cpu(ri->csize)) {
 		ri->dsize = ri->csize;
 		ri->csize = cpu_to_je32(0);
 	}

 	D1(if(ofs + len > je32_to_cpu(ri->dsize)) {
 		printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
 		       len, ofs, je32_to_cpu(ri->dsize));
 		ret = -EINVAL;
 		goto out_ri;
 	});


 	if (ri->compr == JFFS2_COMPR_ZERO) {
 		memset(buf, 0, len);
 		goto out_ri;
 	}

 	/* Cases:
 	   Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
 	   Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
 	   Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
 	   Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
 	*/
 	if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) {
 		readbuf = buf;
 	} else {
 		readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
 		if (!readbuf) {
 			ret = -ENOMEM;
 			goto out_ri;
 		}
 	}
 	if (ri->compr != JFFS2_COMPR_NONE) {
 		if (len < je32_to_cpu(ri->dsize)) {
 			decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
 			if (!decomprbuf) {
 				ret = -ENOMEM;
 				goto out_readbuf;
 			}
 		} else {
 			decomprbuf = buf;
 		}
 	} else {
 		decomprbuf = readbuf;
 	}

 	D2(printk(KERN_DEBUG "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
 		  readbuf));
 	ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri),
 			       je32_to_cpu(ri->csize), &readlen, readbuf);

 	if (!ret && readlen != je32_to_cpu(ri->csize))
 		ret = -EIO;
 	if (ret)
 		goto out_decomprbuf;

 	crc = crc32(0, readbuf, je32_to_cpu(ri->csize));
 	if (crc != je32_to_cpu(ri->data_crc)) {
 		printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n",
 		       je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
 		ret = -EIO;
 		goto out_decomprbuf;
 	}
 	D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc));
 	if (ri->compr != JFFS2_COMPR_NONE) {
 		D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n",
 			  je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf));
 		ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
 		if (ret) {
 			printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret);
 			goto out_decomprbuf;
 		}
 	}

 	if (len < je32_to_cpu(ri->dsize)) {
 		memcpy(buf, decomprbuf+ofs, len);
 	}
  out_decomprbuf:
 	if(decomprbuf != buf && decomprbuf != readbuf)
 		kfree(decomprbuf);
  out_readbuf:
 	if(readbuf != buf)
 		kfree(readbuf);
  out_ri:
 	jffs2_free_raw_inode(ri);

 	return ret;
 }

 int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
 			   unsigned char *buf, uint32_t offset, uint32_t len)
 {
 	uint32_t end = offset + len;
 	struct jffs2_node_frag *frag;
 	int ret;

 	D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n",
 		  f->inocache->ino, offset, offset+len));

 	frag = jffs2_lookup_node_frag(&f->fragtree, offset);

 	/* XXX FIXME: Where a single physical node actually shows up in two
 	   frags, we read it twice. Don't do that. */
 	/* Now we're pointing at the first frag which overlaps our page
 	 * (or perhaps is before it, if we've been asked to read off the
 	 * end of the file). */
 	while(offset < end) {
 		D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end));
 		if (unlikely(!frag || frag->ofs > offset ||
 			     frag->ofs + frag->size <= offset)) {
 			uint32_t holesize = end - offset;
 			if (frag && frag->ofs > offset) {
 				D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset));
 				holesize = min(holesize, frag->ofs - offset);
 			}
 			D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize));
 			memset(buf, 0, holesize);
 			buf += holesize;
 			offset += holesize;
 			continue;
 		} else if (unlikely(!frag->node)) {
 			uint32_t holeend = min(end, frag->ofs + frag->size);
 			D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size));
 			memset(buf, 0, holeend - offset);
 			buf += holeend - offset;
 			offset = holeend;
 			frag = frag_next(frag);
 			continue;
 		} else {
 			uint32_t readlen;
 			uint32_t fragofs; /* offset within the frag to start reading */

 			fragofs = offset - frag->ofs;
 			readlen = min(frag->size - fragofs, end - offset);
 			D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n",
 				  frag->ofs+fragofs, frag->ofs+fragofs+readlen,
 				  ref_offset(frag->node->raw), ref_flags(frag->node->raw)));
 			ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
 			D2(printk(KERN_DEBUG "node read done\n"));
 			if (ret) {
 				D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret));
 				memset(buf, 0, readlen);
 				return ret;
 			}
 			buf += readlen;
 			offset += readlen;
 			frag = frag_next(frag);
 			D2(printk(KERN_DEBUG "node read was OK. Looping\n"));
 		}
 	}
 	return 0;
 }
	/*
	* JFFS2 -- Journalling Flash File System, Version 2.
	*
	* Copyright © 2001-2007 Red Hat, Inc.
	*
	* Created by David Woodhouse <dwmw2@infradead.org>
	*
	* For licensing information, see the file 'LICENCE' in this directory.
	*
	*/

	#include <linux/kernel.h>
	#include <linux/slab.h>
	#include <linux/crc32.h>
	#include <linux/pagemap.h>
	#include <linux/mtd/mtd.h>
	#include <linux/compiler.h>
	#include "nodelist.h"
	#include "compr.h"

	int jffs2_read_dnode(struct jffs2_sb_info c, struct jffs2_inode_info f,
	struct jffs2_full_dnode fd, unsigned char buf,
	int ofs, int len)
	{
	struct jffs2_raw_inode *ri;
	size_t readlen;
	uint32_t crc;
	unsigned char *decomprbuf = NULL;
	unsigned char *readbuf = NULL;
	int ret = 0;

	ri = jffs2_alloc_raw_inode();
	if (!ri)
	return -ENOMEM;

	ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(ri), &readlen, (char )ri);
	if (ret) {
	jffs2_free_raw_inode(ri);
	printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret);
	return ret;
	}
	if (readlen != sizeof(*ri)) {
	jffs2_free_raw_inode(ri);
	printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
	ref_offset(fd->raw), sizeof(*ri), readlen);
	return -EIO;
	}
	crc = crc32(0, ri, sizeof(*ri)-8);

	D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
	ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
	crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
	je32_to_cpu(ri->offset), buf));
	if (crc != je32_to_cpu(ri->node_crc)) {
	printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n",
	je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
	ret = -EIO;
	goto out_ri;
	}
	/* There was a bug where we wrote hole nodes out with csize/dsize
	swapped. Deal with it */
	if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
	je32_to_cpu(ri->csize)) {
	ri->dsize = ri->csize;
	ri->csize = cpu_to_je32(0);
	}

	D1(if(ofs + len > je32_to_cpu(ri->dsize)) {
	printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
	len, ofs, je32_to_cpu(ri->dsize));
	ret = -EINVAL;
	goto out_ri;
	});


	if (ri->compr == JFFS2_COMPR_ZERO) {
	memset(buf, 0, len);
	goto out_ri;
	}

	/* Cases:
	Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
	Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
	Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
	Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
	*/
	if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) {
	readbuf = buf;
	} else {
	readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
	if (!readbuf) {
	ret = -ENOMEM;
	goto out_ri;
	}
	}
	if (ri->compr != JFFS2_COMPR_NONE) {
	if (len < je32_to_cpu(ri->dsize)) {
	decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
	if (!decomprbuf) {
	ret = -ENOMEM;
	goto out_readbuf;
	}
	} else {
	decomprbuf = buf;
	}
	} else {
	decomprbuf = readbuf;
	}

	D2(printk(KERN_DEBUG "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
	readbuf));
	ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri),
	je32_to_cpu(ri->csize), &readlen, readbuf);

	if (!ret && readlen != je32_to_cpu(ri->csize))
	ret = -EIO;
	if (ret)
	goto out_decomprbuf;

	crc = crc32(0, readbuf, je32_to_cpu(ri->csize));
	if (crc != je32_to_cpu(ri->data_crc)) {
	printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n",
	je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
	ret = -EIO;
	goto out_decomprbuf;
	}
	D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc));
	if (ri->compr != JFFS2_COMPR_NONE) {
	D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n",
	je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf));
	ret = jffs2_decompress(c, f, ri->compr \| (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
	if (ret) {
	printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret);
	goto out_decomprbuf;
	}
	}

	if (len < je32_to_cpu(ri->dsize)) {
	memcpy(buf, decomprbuf+ofs, len);
	}
	out_decomprbuf:
	if(decomprbuf != buf && decomprbuf != readbuf)
	kfree(decomprbuf);
	out_readbuf:
	if(readbuf != buf)
	kfree(readbuf);
	out_ri:
	jffs2_free_raw_inode(ri);

	return ret;
	}

	int jffs2_read_inode_range(struct jffs2_sb_info c, struct jffs2_inode_info f,
	unsigned char *buf, uint32_t offset, uint32_t len)
	{
	uint32_t end = offset + len;
	struct jffs2_node_frag *frag;
	int ret;

	D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n",
	f->inocache->ino, offset, offset+len));

	frag = jffs2_lookup_node_frag(&f->fragtree, offset);

	/* XXX FIXME: Where a single physical node actually shows up in two
	frags, we read it twice. Don't do that. */
	/* Now we're pointing at the first frag which overlaps our page
	* (or perhaps is before it, if we've been asked to read off the
	* end of the file). */
	while(offset < end) {
	D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end));
	if (unlikely(!frag \|\| frag->ofs > offset \|\|
	frag->ofs + frag->size <= offset)) {
	uint32_t holesize = end - offset;
	if (frag && frag->ofs > offset) {
	D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset));
	holesize = min(holesize, frag->ofs - offset);
	}
	D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize));
	memset(buf, 0, holesize);
	buf += holesize;
	offset += holesize;
	continue;
	} else if (unlikely(!frag->node)) {
	uint32_t holeend = min(end, frag->ofs + frag->size);
	D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size));
	memset(buf, 0, holeend - offset);
	buf += holeend - offset;
	offset = holeend;
	frag = frag_next(frag);
	continue;
	} else {
	uint32_t readlen;
	uint32_t fragofs; /* offset within the frag to start reading */

	fragofs = offset - frag->ofs;
	readlen = min(frag->size - fragofs, end - offset);
	D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n",
	frag->ofs+fragofs, frag->ofs+fragofs+readlen,
	ref_offset(frag->node->raw), ref_flags(frag->node->raw)));
	ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
	D2(printk(KERN_DEBUG "node read done\n"));
	if (ret) {
	D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret));
	memset(buf, 0, readlen);
	return ret;
	}
	buf += readlen;
	offset += readlen;
	frag = frag_next(frag);
	D2(printk(KERN_DEBUG "node read was OK. Looping\n"));
	}
	}
	return 0;
	}