[linux.git] / fs / jffs2 / read.c

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

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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);
		pr_warn("Error reading node from 0x%08x: %d\n",
			ref_offset(fd->raw), ret);
		return ret;
	}
	if (readlen != sizeof(*ri)) {
		jffs2_free_raw_inode(ri);
		pr_warn("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);

	jffs2_dbg(1, "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)) {
		pr_warn("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)) {
			pr_warn("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;
	}

	jffs2_dbg(2, "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)) {
		pr_warn("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;
	}
	jffs2_dbg(2, "Data CRC matches calculated CRC %08x\n", crc);
	if (ri->compr != JFFS2_COMPR_NONE) {
		jffs2_dbg(2, "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) {
			pr_warn("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;

	jffs2_dbg(1, "%s(): ino #%u, range 0x%08x-0x%08x\n",
		  __func__, 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) {
		jffs2_dbg(2, "%s(): offset %d, end %d\n",
			  __func__, offset, end);
		if (unlikely(!frag || frag->ofs > offset ||
			     frag->ofs + frag->size <= offset)) {
			uint32_t holesize = end - offset;
			if (frag && frag->ofs > offset) {
				jffs2_dbg(1, "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);
			}
			jffs2_dbg(1, "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);
			jffs2_dbg(1, "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);
			jffs2_dbg(1, "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);
			jffs2_dbg(2, "node read done\n");
			if (ret) {
				jffs2_dbg(1, "%s(): error %d\n",
					  __func__, ret);
				memset(buf, 0, readlen);
				return ret;
			}
			buf += readlen;
			offset += readlen;
			frag = frag_next(frag);
			jffs2_dbg(2, "node read was OK. Looping\n");
		}
	}
	return 0;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* JFFS2 -- Journalling Flash File System, Version 2.
	3	*
c00c310e	4	* Copyright © 2001-2007 Red Hat, Inc.
1da177e4 LT	5	*
	6	* Created by David Woodhouse <[email protected]>
	7	*
	8	* For licensing information, see the file 'LICENCE' in this directory.
	9	*
1da177e4 LT	10	*/
1da177e4 LT	11
5a528957 JP	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
5a528957 JP	13
1da177e4 LT	14	#include <linux/kernel.h>
	15	#include <linux/slab.h>
	16	#include <linux/crc32.h>
	17	#include <linux/pagemap.h>
	18	#include <linux/mtd/mtd.h>
	19	#include <linux/compiler.h>
	20	#include "nodelist.h"
	21	#include "compr.h"
	22
	23	int jffs2_read_dnode(struct jffs2_sb_info c, struct jffs2_inode_info f,
	24	struct jffs2_full_dnode fd, unsigned char buf,
	25	int ofs, int len)
	26	{
	27	struct jffs2_raw_inode *ri;
	28	size_t readlen;
	29	uint32_t crc;
	30	unsigned char *decomprbuf = NULL;
	31	unsigned char *readbuf = NULL;
	32	int ret = 0;
	33
	34	ri = jffs2_alloc_raw_inode();
	35	if (!ri)
	36	return -ENOMEM;
	37
	38	ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(ri), &readlen, (char )ri);
	39	if (ret) {
	40	jffs2_free_raw_inode(ri);
da320f05 JP	41	pr_warn("Error reading node from 0x%08x: %d\n",
da320f05 JP	42	ref_offset(fd->raw), ret);
1da177e4 LT	43	return ret;
	44	}
	45	if (readlen != sizeof(*ri)) {
	46	jffs2_free_raw_inode(ri);
da320f05 JP	47	pr_warn("Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
da320f05 JP	48	ref_offset(fd->raw), sizeof(*ri), readlen);
1da177e4 LT	49	return -EIO;
	50	}
	51	crc = crc32(0, ri, sizeof(*ri)-8);
	52
9c261b33	53	jffs2_dbg(1, "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
1da177e4 LT	54	ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
1da177e4 LT	55	crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
9c261b33	56	je32_to_cpu(ri->offset), buf);
1da177e4	57	if (crc != je32_to_cpu(ri->node_crc)) {
da320f05 JP	58	pr_warn("Node CRC %08x != calculated CRC %08x for node at %08x\n",
da320f05 JP	59	je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
1da177e4 LT	60	ret = -EIO;
	61	goto out_ri;
	62	}
	63	/* There was a bug where we wrote hole nodes out with csize/dsize
	64	swapped. Deal with it */
182ec4ee	65	if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
1da177e4 LT	66	je32_to_cpu(ri->csize)) {
	67	ri->dsize = ri->csize;
	68	ri->csize = cpu_to_je32(0);
	69	}
	70
	71	D1(if(ofs + len > je32_to_cpu(ri->dsize)) {
da320f05 JP	72	pr_warn("jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
da320f05 JP	73	len, ofs, je32_to_cpu(ri->dsize));
1da177e4 LT	74	ret = -EINVAL;
	75	goto out_ri;
	76	});
	77
182ec4ee	78
1da177e4 LT	79	if (ri->compr == JFFS2_COMPR_ZERO) {
	80	memset(buf, 0, len);
	81	goto out_ri;
	82	}
	83
	84	/* Cases:
	85	Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
182ec4ee TG	86	Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
182ec4ee TG	87	Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
1da177e4 LT	88	Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
	89	*/
	90	if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) {
	91	readbuf = buf;
	92	} else {
	93	readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
	94	if (!readbuf) {
	95	ret = -ENOMEM;
	96	goto out_ri;
	97	}
	98	}
	99	if (ri->compr != JFFS2_COMPR_NONE) {
	100	if (len < je32_to_cpu(ri->dsize)) {
	101	decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
	102	if (!decomprbuf) {
	103	ret = -ENOMEM;
	104	goto out_readbuf;
	105	}
	106	} else {
	107	decomprbuf = buf;
	108	}
	109	} else {
	110	decomprbuf = readbuf;
	111	}
	112
9c261b33 JP	113	jffs2_dbg(2, "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
9c261b33 JP	114	readbuf);
1da177e4 LT	115	ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri),
	116	je32_to_cpu(ri->csize), &readlen, readbuf);
	117
	118	if (!ret && readlen != je32_to_cpu(ri->csize))
	119	ret = -EIO;
	120	if (ret)
	121	goto out_decomprbuf;
	122
	123	crc = crc32(0, readbuf, je32_to_cpu(ri->csize));
	124	if (crc != je32_to_cpu(ri->data_crc)) {
da320f05 JP	125	pr_warn("Data CRC %08x != calculated CRC %08x for node at %08x\n",
da320f05 JP	126	je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
1da177e4 LT	127	ret = -EIO;
	128	goto out_decomprbuf;
	129	}
9c261b33	130	jffs2_dbg(2, "Data CRC matches calculated CRC %08x\n", crc);
1da177e4	131	if (ri->compr != JFFS2_COMPR_NONE) {
9c261b33 JP	132	jffs2_dbg(2, "Decompress %d bytes from %p to %d bytes at %p\n",
	133	je32_to_cpu(ri->csize), readbuf,
	134	je32_to_cpu(ri->dsize), decomprbuf);
1da177e4 LT	135	ret = jffs2_decompress(c, f, ri->compr \| (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
1da177e4 LT	136	if (ret) {
da320f05	137	pr_warn("Error: jffs2_decompress returned %d\n", ret);
1da177e4 LT	138	goto out_decomprbuf;
	139	}
	140	}
	141
	142	if (len < je32_to_cpu(ri->dsize)) {
	143	memcpy(buf, decomprbuf+ofs, len);
	144	}
	145	out_decomprbuf:
	146	if(decomprbuf != buf && decomprbuf != readbuf)
	147	kfree(decomprbuf);
	148	out_readbuf:
	149	if(readbuf != buf)
	150	kfree(readbuf);
	151	out_ri:
	152	jffs2_free_raw_inode(ri);
	153
	154	return ret;
	155	}
	156
	157	int jffs2_read_inode_range(struct jffs2_sb_info c, struct jffs2_inode_info f,
	158	unsigned char *buf, uint32_t offset, uint32_t len)
	159	{
	160	uint32_t end = offset + len;
	161	struct jffs2_node_frag *frag;
	162	int ret;
	163
9c261b33 JP	164	jffs2_dbg(1, "%s(): ino #%u, range 0x%08x-0x%08x\n",
9c261b33 JP	165	__func__, f->inocache->ino, offset, offset + len);
1da177e4 LT	166
	167	frag = jffs2_lookup_node_frag(&f->fragtree, offset);
	168
	169	/* XXX FIXME: Where a single physical node actually shows up in two
	170	frags, we read it twice. Don't do that. */
199bc9ff DW	171	/* Now we're pointing at the first frag which overlaps our page
	172	* (or perhaps is before it, if we've been asked to read off the
	173	* end of the file). */
1da177e4	174	while(offset < end) {
9c261b33 JP	175	jffs2_dbg(2, "%s(): offset %d, end %d\n",
9c261b33 JP	176	__func__, offset, end);
199bc9ff DW	177	if (unlikely(!frag \|\| frag->ofs > offset \|\|
199bc9ff DW	178	frag->ofs + frag->size <= offset)) {
1da177e4	179	uint32_t holesize = end - offset;
199bc9ff	180	if (frag && frag->ofs > offset) {
9c261b33 JP	181	jffs2_dbg(1, "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n",
9c261b33 JP	182	f->inocache->ino, frag->ofs, offset);
1da177e4	183	holesize = min(holesize, frag->ofs - offset);
1da177e4	184	}
9c261b33 JP	185	jffs2_dbg(1, "Filling non-frag hole from %d-%d\n",
9c261b33 JP	186	offset, offset + holesize);
1da177e4 LT	187	memset(buf, 0, holesize);
	188	buf += holesize;
	189	offset += holesize;
	190	continue;
	191	} else if (unlikely(!frag->node)) {
	192	uint32_t holeend = min(end, frag->ofs + frag->size);
9c261b33 JP	193	jffs2_dbg(1, "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n",
	194	offset, holeend, frag->ofs,
	195	frag->ofs + frag->size);
1da177e4 LT	196	memset(buf, 0, holeend - offset);
	197	buf += holeend - offset;
	198	offset = holeend;
	199	frag = frag_next(frag);
	200	continue;
	201	} else {
	202	uint32_t readlen;
	203	uint32_t fragofs; /* offset within the frag to start reading */
182ec4ee	204
1da177e4 LT	205	fragofs = offset - frag->ofs;
1da177e4 LT	206	readlen = min(frag->size - fragofs, end - offset);
9c261b33 JP	207	jffs2_dbg(1, "Reading %d-%d from node at 0x%08x (%d)\n",
	208	frag->ofs+fragofs,
	209	frag->ofs + fragofs+readlen,
	210	ref_offset(frag->node->raw),
	211	ref_flags(frag->node->raw));
1da177e4	212	ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
9c261b33	213	jffs2_dbg(2, "node read done\n");
1da177e4	214	if (ret) {
9c261b33 JP	215	jffs2_dbg(1, "%s(): error %d\n",
9c261b33 JP	216	__func__, ret);
1da177e4 LT	217	memset(buf, 0, readlen);
	218	return ret;
	219	}
	220	buf += readlen;
	221	offset += readlen;
	222	frag = frag_next(frag);
9c261b33	223	jffs2_dbg(2, "node read was OK. Looping\n");
1da177e4 LT	224	}
	225	}
	226	return 0;
	227	}
	228