11558Srgrimes/* 21558Srgrimes * JFFS2 -- Journalling Flash File System, Version 2. 31558Srgrimes * 41558Srgrimes * Copyright �� 2001-2007 Red Hat, Inc. 51558Srgrimes * 61558Srgrimes * Created by David Woodhouse <dwmw2@infradead.org> 71558Srgrimes * 81558Srgrimes * For licensing information, see the file 'LICENCE' in this directory. 91558Srgrimes * 101558Srgrimes */ 111558Srgrimes 121558Srgrimes#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 131558Srgrimes 141558Srgrimes#include <linux/kernel.h> 151558Srgrimes#include <linux/slab.h> 161558Srgrimes#include <linux/crc32.h> 171558Srgrimes#include <linux/pagemap.h> 181558Srgrimes#include <linux/mtd/mtd.h> 191558Srgrimes#include <linux/compiler.h> 201558Srgrimes#include "nodelist.h" 211558Srgrimes#include "compr.h" 221558Srgrimes 231558Srgrimesint jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, 241558Srgrimes struct jffs2_full_dnode *fd, unsigned char *buf, 251558Srgrimes int ofs, int len) 261558Srgrimes{ 271558Srgrimes struct jffs2_raw_inode *ri; 281558Srgrimes size_t readlen; 291558Srgrimes uint32_t crc; 301558Srgrimes unsigned char *decomprbuf = NULL; 311558Srgrimes unsigned char *readbuf = NULL; 321558Srgrimes int ret = 0; 331558Srgrimes 341558Srgrimes ri = jffs2_alloc_raw_inode(); 3536997Scharnier if (!ri) 361558Srgrimes return -ENOMEM; 371558Srgrimes 381558Srgrimes ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri); 391558Srgrimes if (ret) { 401558Srgrimes jffs2_free_raw_inode(ri); 4136997Scharnier pr_warn("Error reading node from 0x%08x: %d\n", 4223672Speter ref_offset(fd->raw), ret); 4336997Scharnier return ret; 4436997Scharnier } 4550476Speter if (readlen != sizeof(*ri)) { 461558Srgrimes jffs2_free_raw_inode(ri); 471558Srgrimes pr_warn("Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n", 481558Srgrimes ref_offset(fd->raw), sizeof(*ri), readlen); 4958928Sjoerg return -EIO; 501558Srgrimes } 5196478Sphk crc = crc32(0, ri, sizeof(*ri)-8); 521558Srgrimes 5323672Speter jffs2_dbg(1, "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n", 541558Srgrimes ref_offset(fd->raw), je32_to_cpu(ri->node_crc), 551558Srgrimes crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize), 561558Srgrimes je32_to_cpu(ri->offset), buf); 571558Srgrimes if (crc != je32_to_cpu(ri->node_crc)) { 581558Srgrimes pr_warn("Node CRC %08x != calculated CRC %08x for node at %08x\n", 5923672Speter je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw)); 601558Srgrimes ret = -EIO; 611558Srgrimes goto out_ri; 6299562Siedowse } 63103949Smike /* There was a bug where we wrote hole nodes out with csize/dsize 641558Srgrimes swapped. Deal with it */ 651558Srgrimes if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) && 661558Srgrimes je32_to_cpu(ri->csize)) { 671558Srgrimes ri->dsize = ri->csize; 6899562Siedowse ri->csize = cpu_to_je32(0); 691558Srgrimes } 701558Srgrimes 711558Srgrimes D1(if(ofs + len > je32_to_cpu(ri->dsize)) { 721558Srgrimes pr_warn("jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n", 731558Srgrimes len, ofs, je32_to_cpu(ri->dsize)); 741558Srgrimes ret = -EINVAL; 751558Srgrimes goto out_ri; 761558Srgrimes }); 7712377Sjoerg 781558Srgrimes 791558Srgrimes if (ri->compr == JFFS2_COMPR_ZERO) { 8025288Swollman memset(buf, 0, len); 811558Srgrimes goto out_ri; 821558Srgrimes } 831558Srgrimes 841558Srgrimes /* Cases: 8598542Smckusick Reading whole node and it's uncompressed - read directly to buffer provided, check CRC. 8698542Smckusick Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided 8798542Smckusick Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy 8898542Smckusick Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy 8998542Smckusick */ 9092837Simp if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) { 9192837Simp readbuf = buf; 9292837Simp } else { 931558Srgrimes readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL); 941558Srgrimes if (!readbuf) { 9592837Simp ret = -ENOMEM; 961558Srgrimes goto out_ri; 9786470Siedowse } 9886473Siedowse } 9986473Siedowse if (ri->compr != JFFS2_COMPR_NONE) { 10098542Smckusick if (len < je32_to_cpu(ri->dsize)) { 10186473Siedowse decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL); 10286473Siedowse if (!decomprbuf) { 10398542Smckusick ret = -ENOMEM; 1041558Srgrimes goto out_readbuf; 10591540Siedowse } 1061558Srgrimes } else { 10785635Sdillon decomprbuf = buf; 1081558Srgrimes } 10998542Smckusick } else { 1101558Srgrimes decomprbuf = readbuf; 1111558Srgrimes } 11221409Simp 11321409Simp jffs2_dbg(2, "Read %d bytes to %p\n", je32_to_cpu(ri->csize), 1141558Srgrimes readbuf); 1151558Srgrimes ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri), 1161558Srgrimes je32_to_cpu(ri->csize), &readlen, readbuf); 1171558Srgrimes 1181558Srgrimes if (!ret && readlen != je32_to_cpu(ri->csize)) 1191558Srgrimes ret = -EIO; 12023672Speter if (ret) 12123672Speter goto out_decomprbuf; 1221558Srgrimes 12323672Speter crc = crc32(0, readbuf, je32_to_cpu(ri->csize)); 12425288Swollman if (crc != je32_to_cpu(ri->data_crc)) { 12591540Siedowse pr_warn("Data CRC %08x != calculated CRC %08x for node at %08x\n", 12625288Swollman je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw)); 12791540Siedowse ret = -EIO; 12825288Swollman goto out_decomprbuf; 12925288Swollman } 13025288Swollman jffs2_dbg(2, "Data CRC matches calculated CRC %08x\n", crc); 13123672Speter if (ri->compr != JFFS2_COMPR_NONE) { 13223672Speter jffs2_dbg(2, "Decompress %d bytes from %p to %d bytes at %p\n", 13323672Speter je32_to_cpu(ri->csize), readbuf, 13423672Speter je32_to_cpu(ri->dsize), decomprbuf); 13523672Speter ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize)); 1361558Srgrimes if (ret) { 1371558Srgrimes pr_warn("Error: jffs2_decompress returned %d\n", ret); 13823672Speter goto out_decomprbuf; 13923672Speter } 1401558Srgrimes } 1411558Srgrimes 14223672Speter if (len < je32_to_cpu(ri->dsize)) { 14323672Speter memcpy(buf, decomprbuf+ofs, len); 14423672Speter } 1451558Srgrimes out_decomprbuf: 1461558Srgrimes if(decomprbuf != buf && decomprbuf != readbuf) 1471558Srgrimes kfree(decomprbuf); 14823672Speter out_readbuf: 14923672Speter if(readbuf != buf) 1501558Srgrimes kfree(readbuf); 1511558Srgrimes out_ri: 1521558Srgrimes jffs2_free_raw_inode(ri); 1531558Srgrimes 1541558Srgrimes return ret; 1551558Srgrimes} 15623672Speter 15723672Speterint jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f, 15823672Speter unsigned char *buf, uint32_t offset, uint32_t len) 15923672Speter{ 16022192Sjoerg uint32_t end = offset + len; 16122192Sjoerg struct jffs2_node_frag *frag; 16223672Speter int ret; 16323672Speter 1641558Srgrimes jffs2_dbg(1, "%s(): ino #%u, range 0x%08x-0x%08x\n", 1651558Srgrimes __func__, f->inocache->ino, offset, offset + len); 16679427Sdillon 16779427Sdillon frag = jffs2_lookup_node_frag(&f->fragtree, offset); 16879427Sdillon 16979427Sdillon /* XXX FIXME: Where a single physical node actually shows up in two 17023672Speter frags, we read it twice. Don't do that. */ 17123672Speter /* Now we're pointing at the first frag which overlaps our page 1721558Srgrimes * (or perhaps is before it, if we've been asked to read off the 1731558Srgrimes * end of the file). */ 17425288Swollman while(offset < end) { 17525288Swollman jffs2_dbg(2, "%s(): offset %d, end %d\n", 17625288Swollman __func__, offset, end); 17725288Swollman if (unlikely(!frag || frag->ofs > offset || 17825288Swollman frag->ofs + frag->size <= offset)) { 17925288Swollman uint32_t holesize = end - offset; 1801558Srgrimes if (frag && frag->ofs > offset) { 1811558Srgrimes jffs2_dbg(1, "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", 1821558Srgrimes f->inocache->ino, frag->ofs, offset); 1831558Srgrimes holesize = min(holesize, frag->ofs - offset); 18423672Speter } 18523672Speter jffs2_dbg(1, "Filling non-frag hole from %d-%d\n", 1861558Srgrimes offset, offset + holesize); 1871558Srgrimes memset(buf, 0, holesize); 18891540Siedowse buf += holesize; 18991540Siedowse offset += holesize; 19091540Siedowse continue; 19191540Siedowse } else if (unlikely(!frag->node)) { 19223672Speter uint32_t holeend = min(end, frag->ofs + frag->size); 19323672Speter jffs2_dbg(1, "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", 19423672Speter offset, holeend, frag->ofs, 19523672Speter frag->ofs + frag->size); 19623672Speter memset(buf, 0, holeend - offset); 19737635Sjkoshy buf += holeend - offset; 19823672Speter offset = holeend; 19923672Speter frag = frag_next(frag); 20023672Speter continue; 20123672Speter } else { 20223672Speter uint32_t readlen; 20323672Speter uint32_t fragofs; /* offset within the frag to start reading */ 20423672Speter 20523672Speter fragofs = offset - frag->ofs; 20623672Speter readlen = min(frag->size - fragofs, end - offset); 20723672Speter jffs2_dbg(1, "Reading %d-%d from node at 0x%08x (%d)\n", 20823672Speter frag->ofs+fragofs, 20923672Speter frag->ofs + fragofs+readlen, 21037635Sjkoshy ref_offset(frag->node->raw), 21123672Speter ref_flags(frag->node->raw)); 2121558Srgrimes ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen); 21323672Speter jffs2_dbg(2, "node read done\n"); 2141558Srgrimes if (ret) { 21523672Speter jffs2_dbg(1, "%s(): error %d\n", 21623672Speter __func__, ret); 21723672Speter memset(buf, 0, readlen); 2181558Srgrimes return ret; 219102231Strhodes } 22037635Sjkoshy buf += readlen; 2211558Srgrimes offset += readlen; 2221558Srgrimes frag = frag_next(frag); 2231558Srgrimes jffs2_dbg(2, "node read was OK. Looping\n"); 2241558Srgrimes } 2251558Srgrimes } 2261558Srgrimes return 0; 2271558Srgrimes} 2281558Srgrimes 22937635Sjkoshy