1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright (C) 2001-2003 Red Hat, Inc.
5 *
6 * Created by David Woodhouse <[email protected]>
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
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)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,i=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, (unsigned 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 //add for debug
134 // for (i=0; i<je32_to_cpu(ri->csize); i++)
135 // {
136 // printf("%02x ", readbuf[i]);
137 // if( (i+1) % 16 == 0)
138 // printf("\n");
139 // }
140 //end debug
141 ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
142 if (ret) {
143 printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret);
144 goto out_decomprbuf;
145 }
146 }
147
148 if (len < je32_to_cpu(ri->dsize)) {
149 memcpy(buf, decomprbuf+ofs, len);
150 }
151 out_decomprbuf:
152 if(decomprbuf != buf && decomprbuf != readbuf)
153 kfree(decomprbuf);
154 out_readbuf:
155 if(readbuf != buf)
156 kfree(readbuf);
157 out_ri:
158 jffs2_free_raw_inode(ri);
159
160 return ret;
161 }
162
jffs2_read_inode_range(struct jffs2_sb_info * c,struct jffs2_inode_info * f,unsigned char * buf,uint32_t offset,uint32_t len)163 int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
164 unsigned char *buf, uint32_t offset, uint32_t len)
165 {
166 uint32_t end = offset + len;
167 struct jffs2_node_frag *frag;
168 int ret;
169
170 D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n",
171 f->inocache->ino, offset, offset+len));
172
173 frag = jffs2_lookup_node_frag(&f->fragtree, offset);
174
175 /* XXX FIXME: Where a single physical node actually shows up in two
176 frags, we read it twice. Don't do that. */
177 /* Now we're pointing at the first frag which overlaps our page */
178 while(offset < end) {
179 D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end));
180 if (unlikely(!frag || frag->ofs > offset)) {
181 uint32_t holesize = end - offset;
182 if (frag) {
183 D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset));
184 holesize = min(holesize, frag->ofs - offset);
185 }
186 D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize));
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);
193 D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size));
194 memset(buf, 0, holeend - offset);
195 buf += holeend - offset;
196 offset = holeend;
197 frag = frag_next(frag);
198 continue;
199 } else {
200 uint32_t readlen;
201 uint32_t fragofs; /* offset within the frag to start reading */
202
203 fragofs = offset - frag->ofs;
204 readlen = min(frag->size - fragofs, end - offset);
205 D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n",
206 frag->ofs+fragofs, frag->ofs+fragofs+readlen,
207 ref_offset(frag->node->raw), ref_flags(frag->node->raw)));
208 ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
209 D2(printk(KERN_DEBUG "node read done\n"));
210 if (ret) {
211 D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret));
212 memset(buf, 0, readlen);
213 return ret;
214 }
215 buf += readlen;
216 offset += readlen;
217 frag = frag_next(frag);
218 D2(printk(KERN_DEBUG "node read was OK. Looping\n"));
219 }
220 }
221 return 0;
222 }
223
224