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 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/pagemap.h>
15 #include <linux/compiler.h>
16 #include <mtd_dev.h>
17 #include "nodelist.h"
18 #include "compr.h"
19 #include "los_crc32.h"
20 #include "user_copy.h"
21
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)22 int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
23 struct jffs2_full_dnode *fd, unsigned char *buf,
24 int ofs, int len)
25 {
26 struct jffs2_raw_inode *ri;
27 size_t readlen;
28 uint32_t crc;
29 unsigned char *decomprbuf = NULL;
30 unsigned char *readbuf = NULL;
31 int ret = 0;
32
33 ri = jffs2_alloc_raw_inode();
34 if (!ri)
35 return -ENOMEM;
36
37 ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri);
38 if (ret) {
39 jffs2_free_raw_inode(ri);
40 pr_warn("Error reading node from 0x%08x: %d\n",
41 ref_offset(fd->raw), ret);
42 return ret;
43 }
44 if (readlen != sizeof(*ri)) {
45 jffs2_free_raw_inode(ri);
46 pr_warn("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 jffs2_dbg(1, "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 pr_warn("Node CRC %08x != calculated CRC %08x for node at %08x\n",
58 je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
59 jffs2_dbg_dump_node(c, 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 if (ri->compr == JFFS2_COMPR_ZERO) {
79 ret = LOS_UserMemClear(buf, 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 = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
91 if (!readbuf) {
92 ret = -ENOMEM;
93 goto out_ri;
94 }
95 } else {
96 readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
97 if (!readbuf) {
98 ret = -ENOMEM;
99 goto out_ri;
100 }
101 }
102 if (ri->compr != JFFS2_COMPR_NONE) {
103 decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
104 if (!decomprbuf) {
105 ret = -ENOMEM;
106 goto out_readbuf;
107 }
108 } else {
109 decomprbuf = readbuf;
110 }
111
112 jffs2_dbg(2, "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, (char *)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 pr_warn("Data CRC %08x != calculated CRC %08x for node at %08x\n",
125 je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
126 jffs2_dbg_dump_node(c, 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 (LOS_CopyFromKernel(buf, len, decomprbuf + ofs, len) != 0) {
143 ret = -EFAULT;
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 ret = LOS_UserMemClear(buf, holesize);
188 if (ret != 0) {
189 return ret;
190 }
191 buf += holesize;
192 offset += holesize;
193 continue;
194 } else if (unlikely(!frag->node)) {
195 uint32_t holeend = min(end, frag->ofs + frag->size);
196 jffs2_dbg(1, "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n",
197 offset, holeend, frag->ofs,
198 frag->ofs + frag->size);
199 ret = LOS_UserMemClear(buf, holeend - offset);
200 if (ret != 0) {
201 return ret;
202 }
203 buf += holeend - offset;
204 offset = holeend;
205 frag = frag_next(frag);
206 continue;
207 } else {
208 uint32_t readlen;
209 uint32_t fragofs; /* offset within the frag to start reading */
210
211 fragofs = offset - frag->ofs;
212 readlen = min(frag->size - fragofs, end - offset);
213 jffs2_dbg(1, "Reading %d-%d from node at 0x%08x (%d)\n",
214 frag->ofs+fragofs,
215 frag->ofs + fragofs+readlen,
216 ref_offset(frag->node->raw),
217 ref_flags(frag->node->raw));
218 ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
219 jffs2_dbg(2, "node read done\n");
220 if (ret) {
221 jffs2_dbg(1, "%s(): error %d\n",
222 __func__, ret);
223 (void)LOS_UserMemClear(buf, readlen);
224 return ret;
225 }
226 buf += readlen;
227 offset += readlen;
228 frag = frag_next(frag);
229 jffs2_dbg(2, "node read was OK. Looping\n");
230 }
231 }
232 return 0;
233 }
234
jffs2_flash_direct_read(struct jffs2_sb_info * c,loff_t ofs,size_t len,size_t * retlen,const char * buf)235 int jffs2_flash_direct_read(struct jffs2_sb_info *c, loff_t ofs, size_t len,
236 size_t *retlen, const char *buf)
237 {
238 int ret;
239 ret = c->mtd->read(c->mtd, ofs, len, (char *)buf);
240 if (ret >= 0) {
241 *retlen = ret;
242 return 0;
243 }
244 *retlen = 0;
245 return ret;
246 }