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/crc32.h>
15#include <linux/pagemap.h>
16#include <linux/mtd/mtd.h>
17#include <linux/compiler.h>
18#include "nodelist.h"
19#include "compr.h"
20
21int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
22		     struct jffs2_full_dnode *fd, unsigned char *buf,
23		     int ofs, int len)
24{
25	struct jffs2_raw_inode *ri;
26	size_t readlen;
27	uint32_t crc;
28	unsigned char *decomprbuf = NULL;
29	unsigned char *readbuf = NULL;
30	int ret = 0;
31
32	ri = jffs2_alloc_raw_inode();
33	if (!ri)
34		return -ENOMEM;
35
36	ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri);
37	if (ret) {
38		jffs2_free_raw_inode(ri);
39		printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret);
40		return ret;
41	}
42	if (readlen != sizeof(*ri)) {
43		jffs2_free_raw_inode(ri);
44		printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
45		       ref_offset(fd->raw), sizeof(*ri), readlen);
46		return -EIO;
47	}
48	crc = crc32(0, ri, sizeof(*ri)-8);
49
50	D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
51		  ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
52		  crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
53		  je32_to_cpu(ri->offset), buf));
54	if (crc != je32_to_cpu(ri->node_crc)) {
55		printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n",
56		       je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
57		ret = -EIO;
58		goto out_ri;
59	}
60	/* There was a bug where we wrote hole nodes out with csize/dsize
61	   swapped. Deal with it */
62	if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
63	    je32_to_cpu(ri->csize)) {
64		ri->dsize = ri->csize;
65		ri->csize = cpu_to_je32(0);
66	}
67
68	D1(if(ofs + len > je32_to_cpu(ri->dsize)) {
69		printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
70		       len, ofs, je32_to_cpu(ri->dsize));
71		ret = -EINVAL;
72		goto out_ri;
73	});
74
75
76	if (ri->compr == JFFS2_COMPR_ZERO) {
77		memset(buf, 0, len);
78		goto out_ri;
79	}
80
81	/* Cases:
82	   Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
83	   Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
84	   Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
85	   Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
86	*/
87	if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) {
88		readbuf = buf;
89	} else {
90		readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
91		if (!readbuf) {
92			ret = -ENOMEM;
93			goto out_ri;
94		}
95	}
96	if (ri->compr != JFFS2_COMPR_NONE) {
97		if (len < je32_to_cpu(ri->dsize)) {
98			decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
99			if (!decomprbuf) {
100				ret = -ENOMEM;
101				goto out_readbuf;
102			}
103		} else {
104			decomprbuf = buf;
105		}
106	} else {
107		decomprbuf = readbuf;
108	}
109
110	D2(printk(KERN_DEBUG "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
111		  readbuf));
112	ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri),
113			       je32_to_cpu(ri->csize), &readlen, readbuf);
114
115	if (!ret && readlen != je32_to_cpu(ri->csize))
116		ret = -EIO;
117	if (ret)
118		goto out_decomprbuf;
119
120	crc = crc32(0, readbuf, je32_to_cpu(ri->csize));
121	if (crc != je32_to_cpu(ri->data_crc)) {
122		printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n",
123		       je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
124		ret = -EIO;
125		goto out_decomprbuf;
126	}
127	D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc));
128	if (ri->compr != JFFS2_COMPR_NONE) {
129		D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n",
130			  je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf));
131		ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
132		if (ret) {
133			printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret);
134			goto out_decomprbuf;
135		}
136	}
137
138	if (len < je32_to_cpu(ri->dsize)) {
139		memcpy(buf, decomprbuf+ofs, len);
140	}
141 out_decomprbuf:
142	if(decomprbuf != buf && decomprbuf != readbuf)
143		kfree(decomprbuf);
144 out_readbuf:
145	if(readbuf != buf)
146		kfree(readbuf);
147 out_ri:
148	jffs2_free_raw_inode(ri);
149
150	return ret;
151}
152
153int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
154			   unsigned char *buf, uint32_t offset, uint32_t len)
155{
156	uint32_t end = offset + len;
157	struct jffs2_node_frag *frag;
158	int ret;
159
160	D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n",
161		  f->inocache->ino, offset, offset+len));
162
163	frag = jffs2_lookup_node_frag(&f->fragtree, offset);
164
165	/* Now we're pointing at the first frag which overlaps our page */
166	while(offset < end) {
167		D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end));
168		if (unlikely(!frag || frag->ofs > offset)) {
169			uint32_t holesize = end - offset;
170			if (frag) {
171				D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset));
172				holesize = min(holesize, frag->ofs - offset);
173			}
174			D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize));
175			memset(buf, 0, holesize);
176			buf += holesize;
177			offset += holesize;
178			continue;
179		} else if (unlikely(!frag->node)) {
180			uint32_t holeend = min(end, frag->ofs + frag->size);
181			D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size));
182			memset(buf, 0, holeend - offset);
183			buf += holeend - offset;
184			offset = holeend;
185			frag = frag_next(frag);
186			continue;
187		} else {
188			uint32_t readlen;
189			uint32_t fragofs; /* offset within the frag to start reading */
190
191			fragofs = offset - frag->ofs;
192			readlen = min(frag->size - fragofs, end - offset);
193			D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n",
194				  frag->ofs+fragofs, frag->ofs+fragofs+readlen,
195				  ref_offset(frag->node->raw), ref_flags(frag->node->raw)));
196			ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
197			D2(printk(KERN_DEBUG "node read done\n"));
198			if (ret) {
199				D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret));
200				memset(buf, 0, readlen);
201				return ret;
202			}
203			buf += readlen;
204			offset += readlen;
205			frag = frag_next(frag);
206			D2(printk(KERN_DEBUG "node read was OK. Looping\n"));
207		}
208	}
209	return 0;
210}
211