1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2001-2007 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 */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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;
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 pr_warn("Error reading node from 0x%08x: %d\n",
42 ref_offset(fd->raw), ret);
43 return ret;
44 }
45 if (readlen != sizeof(*ri)) {
46 jffs2_free_raw_inode(ri);
47 pr_warn("Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
48 ref_offset(fd->raw), sizeof(*ri), readlen);
49 return -EIO;
50 }
51 crc = crc32(0, ri, sizeof(*ri)-8);
52
53 jffs2_dbg(1, "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
54 ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
55 crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
56 je32_to_cpu(ri->offset), buf);
57 if (crc != je32_to_cpu(ri->node_crc)) {
58 pr_warn("Node CRC %08x != calculated CRC %08x for node at %08x\n",
59 je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
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 */
65 if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
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)) {
72 pr_warn("jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
73 len, ofs, je32_to_cpu(ri->dsize));
74 ret = -EINVAL;
75 goto out_ri;
76 });
77
78
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.
86 Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
87 Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
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
113 jffs2_dbg(2, "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
114 readbuf);
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)) {
125 pr_warn("Data CRC %08x != calculated CRC %08x for node at %08x\n",
126 je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
127 ret = -EIO;
128 goto out_decomprbuf;
129 }
130 jffs2_dbg(2, "Data CRC matches calculated CRC %08x\n", crc);
131 if (ri->compr != JFFS2_COMPR_NONE) {
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);
135 ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
136 if (ret) {
137 pr_warn("Error: jffs2_decompress returned %d\n", ret);
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
jffs2_read_inode_range(struct jffs2_sb_info * c,struct jffs2_inode_info * f,unsigned char * buf,uint32_t offset,uint32_t len)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
164 jffs2_dbg(1, "%s(): ino #%u, range 0x%08x-0x%08x\n",
165 __func__, f->inocache->ino, offset, offset + len);
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. */
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). */
174 while(offset < end) {
175 jffs2_dbg(2, "%s(): offset %d, end %d\n",
176 __func__, offset, end);
177 if (unlikely(!frag || frag->ofs > offset ||
178 frag->ofs + frag->size <= offset)) {
179 uint32_t holesize = end - offset;
180 if (frag && frag->ofs > offset) {
181 jffs2_dbg(1, "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n",
182 f->inocache->ino, frag->ofs, offset);
183 holesize = min(holesize, frag->ofs - offset);
184 }
185 jffs2_dbg(1, "Filling non-frag hole from %d-%d\n",
186 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 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);
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 */
204
205 fragofs = offset - frag->ofs;
206 readlen = min(frag->size - fragofs, end - offset);
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));
212 ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
213 jffs2_dbg(2, "node read done\n");
214 if (ret) {
215 jffs2_dbg(1, "%s(): error %d\n",
216 __func__, ret);
217 memset(buf, 0, readlen);
218 return ret;
219 }
220 buf += readlen;
221 offset += readlen;
222 frag = frag_next(frag);
223 jffs2_dbg(2, "node read was OK. Looping\n");
224 }
225 }
226 return 0;
227 }
228
229