1 /* 2 * JFFS2 -- Journalling Flash File System, Version 2. 3 * 4 * Copyright (C) 2001-2003 Red Hat, Inc. 5 * 6 * Created by David Woodhouse <dwmw2@infradead.org> 7 * 8 * For licensing information, see the file 'LICENCE' in this directory. 9 * 10 * $Id: read.c,v 1.41 2005/07/22 10:32:08 dedekind Exp $ 11 * 12 */ 13 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); 41 printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret); 42 return ret; 43 } 44 if (readlen != sizeof(*ri)) { 45 jffs2_free_raw_inode(ri); 46 printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n", 47 ref_offset(fd->raw), sizeof(*ri), readlen); 48 return -EIO; 49 } 50 crc = crc32(0, ri, sizeof(*ri)-8); 51 52 D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n", 53 ref_offset(fd->raw), je32_to_cpu(ri->node_crc), 54 crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize), 55 je32_to_cpu(ri->offset), buf)); 56 if (crc != je32_to_cpu(ri->node_crc)) { 57 printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n", 58 je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw)); 59 ret = -EIO; 60 goto out_ri; 61 } 62 /* There was a bug where we wrote hole nodes out with csize/dsize 63 swapped. Deal with it */ 64 if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) && 65 je32_to_cpu(ri->csize)) { 66 ri->dsize = ri->csize; 67 ri->csize = cpu_to_je32(0); 68 } 69 70 D1(if(ofs + len > je32_to_cpu(ri->dsize)) { 71 printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n", 72 len, ofs, je32_to_cpu(ri->dsize)); 73 ret = -EINVAL; 74 goto out_ri; 75 }); 76 77 78 if (ri->compr == JFFS2_COMPR_ZERO) { 79 memset(buf, 0, len); 80 goto out_ri; 81 } 82 83 /* Cases: 84 Reading whole node and it's uncompressed - read directly to buffer provided, check CRC. 85 Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided 86 Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy 87 Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy 88 */ 89 if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) { 90 readbuf = buf; 91 } else { 92 readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL); 93 if (!readbuf) { 94 ret = -ENOMEM; 95 goto out_ri; 96 } 97 } 98 if (ri->compr != JFFS2_COMPR_NONE) { 99 if (len < je32_to_cpu(ri->dsize)) { 100 decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL); 101 if (!decomprbuf) { 102 ret = -ENOMEM; 103 goto out_readbuf; 104 } 105 } else { 106 decomprbuf = buf; 107 } 108 } else { 109 decomprbuf = readbuf; 110 } 111 112 D2(printk(KERN_DEBUG "Read %d bytes to %p\n", je32_to_cpu(ri->csize), 113 readbuf)); 114 ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri), 115 je32_to_cpu(ri->csize), &readlen, readbuf); 116 117 if (!ret && readlen != je32_to_cpu(ri->csize)) 118 ret = -EIO; 119 if (ret) 120 goto out_decomprbuf; 121 122 crc = crc32(0, readbuf, je32_to_cpu(ri->csize)); 123 if (crc != je32_to_cpu(ri->data_crc)) { 124 printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n", 125 je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw)); 126 ret = -EIO; 127 goto out_decomprbuf; 128 } 129 D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc)); 130 if (ri->compr != JFFS2_COMPR_NONE) { 131 D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n", 132 je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf)); 133 ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize)); 134 if (ret) { 135 printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret); 136 goto out_decomprbuf; 137 } 138 } 139 140 if (len < je32_to_cpu(ri->dsize)) { 141 memcpy(buf, decomprbuf+ofs, len); 142 } 143 out_decomprbuf: 144 if(decomprbuf != buf && decomprbuf != readbuf) 145 kfree(decomprbuf); 146 out_readbuf: 147 if(readbuf != buf) 148 kfree(readbuf); 149 out_ri: 150 jffs2_free_raw_inode(ri); 151 152 return ret; 153 } 154 155 int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f, 156 unsigned char *buf, uint32_t offset, uint32_t len) 157 { 158 uint32_t end = offset + len; 159 struct jffs2_node_frag *frag; 160 int ret; 161 162 D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n", 163 f->inocache->ino, offset, offset+len)); 164 165 frag = jffs2_lookup_node_frag(&f->fragtree, offset); 166 167 /* XXX FIXME: Where a single physical node actually shows up in two 168 frags, we read it twice. Don't do that. */ 169 /* Now we're pointing at the first frag which overlaps our page */ 170 while(offset < end) { 171 D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end)); 172 if (unlikely(!frag || frag->ofs > offset)) { 173 uint32_t holesize = end - offset; 174 if (frag) { 175 D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset)); 176 holesize = min(holesize, frag->ofs - offset); 177 } 178 D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize)); 179 memset(buf, 0, holesize); 180 buf += holesize; 181 offset += holesize; 182 continue; 183 } else if (unlikely(!frag->node)) { 184 uint32_t holeend = min(end, frag->ofs + frag->size); 185 D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size)); 186 memset(buf, 0, holeend - offset); 187 buf += holeend - offset; 188 offset = holeend; 189 frag = frag_next(frag); 190 continue; 191 } else { 192 uint32_t readlen; 193 uint32_t fragofs; /* offset within the frag to start reading */ 194 195 fragofs = offset - frag->ofs; 196 readlen = min(frag->size - fragofs, end - offset); 197 D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n", 198 frag->ofs+fragofs, frag->ofs+fragofs+readlen, 199 ref_offset(frag->node->raw), ref_flags(frag->node->raw))); 200 ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen); 201 D2(printk(KERN_DEBUG "node read done\n")); 202 if (ret) { 203 D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret)); 204 memset(buf, 0, readlen); 205 return ret; 206 } 207 buf += readlen; 208 offset += readlen; 209 frag = frag_next(frag); 210 D2(printk(KERN_DEBUG "node read was OK. Looping\n")); 211 } 212 } 213 return 0; 214 } 215 216