1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
|
/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright (C) 2001-2003 Red Hat, Inc.
*
* Created by David Woodhouse <dwmw2@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
* $Id: read.c,v 1.38 2004/11/16 20:36:12 dwmw2 Exp $
*
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/crc32.h>
#include <linux/pagemap.h>
#include <linux/mtd/mtd.h>
#include <linux/compiler.h>
#include "nodelist.h"
#include "compr.h"
int 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)
{
struct jffs2_raw_inode *ri;
size_t readlen;
uint32_t crc;
unsigned char *decomprbuf = NULL;
unsigned char *readbuf = NULL;
int ret = 0;
ri = jffs2_alloc_raw_inode();
if (!ri)
return -ENOMEM;
ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri);
if (ret) {
jffs2_free_raw_inode(ri);
printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret);
return ret;
}
if (readlen != sizeof(*ri)) {
jffs2_free_raw_inode(ri);
printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
ref_offset(fd->raw), sizeof(*ri), readlen);
return -EIO;
}
crc = crc32(0, ri, sizeof(*ri)-8);
D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
je32_to_cpu(ri->offset), buf));
if (crc != je32_to_cpu(ri->node_crc)) {
printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n",
je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
ret = -EIO;
goto out_ri;
}
/* There was a bug where we wrote hole nodes out with csize/dsize
swapped. Deal with it */
if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
je32_to_cpu(ri->csize)) {
ri->dsize = ri->csize;
ri->csize = cpu_to_je32(0);
}
D1(if(ofs + len > je32_to_cpu(ri->dsize)) {
printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
len, ofs, je32_to_cpu(ri->dsize));
ret = -EINVAL;
goto out_ri;
});
if (ri->compr == JFFS2_COMPR_ZERO) {
memset(buf, 0, len);
goto out_ri;
}
/* Cases:
Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
*/
if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) {
readbuf = buf;
} else {
readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
if (!readbuf) {
ret = -ENOMEM;
goto out_ri;
}
}
if (ri->compr != JFFS2_COMPR_NONE) {
if (len < je32_to_cpu(ri->dsize)) {
decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
if (!decomprbuf) {
ret = -ENOMEM;
goto out_readbuf;
}
} else {
decomprbuf = buf;
}
} else {
decomprbuf = readbuf;
}
D2(printk(KERN_DEBUG "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
readbuf));
ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri),
je32_to_cpu(ri->csize), &readlen, readbuf);
if (!ret && readlen != je32_to_cpu(ri->csize))
ret = -EIO;
if (ret)
goto out_decomprbuf;
crc = crc32(0, readbuf, je32_to_cpu(ri->csize));
if (crc != je32_to_cpu(ri->data_crc)) {
printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n",
je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
ret = -EIO;
goto out_decomprbuf;
}
D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc));
if (ri->compr != JFFS2_COMPR_NONE) {
D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n",
je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf));
ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
if (ret) {
printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret);
goto out_decomprbuf;
}
}
if (len < je32_to_cpu(ri->dsize)) {
memcpy(buf, decomprbuf+ofs, len);
}
out_decomprbuf:
if(decomprbuf != buf && decomprbuf != readbuf)
kfree(decomprbuf);
out_readbuf:
if(readbuf != buf)
kfree(readbuf);
out_ri:
jffs2_free_raw_inode(ri);
return ret;
}
int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
unsigned char *buf, uint32_t offset, uint32_t len)
{
uint32_t end = offset + len;
struct jffs2_node_frag *frag;
int ret;
D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n",
f->inocache->ino, offset, offset+len));
frag = jffs2_lookup_node_frag(&f->fragtree, offset);
/* XXX FIXME: Where a single physical node actually shows up in two
frags, we read it twice. Don't do that. */
/* Now we're pointing at the first frag which overlaps our page */
while(offset < end) {
D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end));
if (unlikely(!frag || frag->ofs > offset)) {
uint32_t holesize = end - offset;
if (frag) {
D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset));
holesize = min(holesize, frag->ofs - offset);
D2(jffs2_print_frag_list(f));
}
D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize));
memset(buf, 0, holesize);
buf += holesize;
offset += holesize;
continue;
} else if (unlikely(!frag->node)) {
uint32_t holeend = min(end, frag->ofs + frag->size);
D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size));
memset(buf, 0, holeend - offset);
buf += holeend - offset;
offset = holeend;
frag = frag_next(frag);
continue;
} else {
uint32_t readlen;
uint32_t fragofs; /* offset within the frag to start reading */
fragofs = offset - frag->ofs;
readlen = min(frag->size - fragofs, end - offset);
D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n",
frag->ofs+fragofs, frag->ofs+fragofs+readlen,
ref_offset(frag->node->raw), ref_flags(frag->node->raw)));
ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
D2(printk(KERN_DEBUG "node read done\n"));
if (ret) {
D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret));
memset(buf, 0, readlen);
return ret;
}
buf += readlen;
offset += readlen;
frag = frag_next(frag);
D2(printk(KERN_DEBUG "node read was OK. Looping\n"));
}
}
return 0;
}
/* Core function to read symlink target. */
char *jffs2_getlink(struct jffs2_sb_info *c, struct jffs2_inode_info *f)
{
char *buf;
int ret;
down(&f->sem);
if (!f->metadata) {
printk(KERN_NOTICE "No metadata for symlink inode #%u\n", f->inocache->ino);
up(&f->sem);
return ERR_PTR(-EINVAL);
}
buf = kmalloc(f->metadata->size+1, GFP_USER);
if (!buf) {
up(&f->sem);
return ERR_PTR(-ENOMEM);
}
buf[f->metadata->size]=0;
ret = jffs2_read_dnode(c, f, f->metadata, buf, 0, f->metadata->size);
up(&f->sem);
if (ret) {
kfree(buf);
return ERR_PTR(ret);
}
return buf;
}
|
