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228 lines
6.7 KiB
228 lines
6.7 KiB
/* |
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* JFFS2 -- Journalling Flash File System, Version 2. |
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* |
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* Copyright © 2001-2007 Red Hat, Inc. |
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* |
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* Created by David Woodhouse <[email protected]> |
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* |
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* For licensing information, see the file 'LICENCE' in this directory. |
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* |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include <linux/crc32.h> |
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#include <linux/pagemap.h> |
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#include <linux/mtd/mtd.h> |
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#include <linux/compiler.h> |
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#include "nodelist.h" |
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#include "compr.h" |
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int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, |
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struct jffs2_full_dnode *fd, unsigned char *buf, |
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int ofs, int len) |
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{ |
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struct jffs2_raw_inode *ri; |
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size_t readlen; |
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uint32_t crc; |
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unsigned char *decomprbuf = NULL; |
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unsigned char *readbuf = NULL; |
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int ret = 0; |
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ri = jffs2_alloc_raw_inode(); |
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if (!ri) |
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return -ENOMEM; |
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ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri); |
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if (ret) { |
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jffs2_free_raw_inode(ri); |
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pr_warn("Error reading node from 0x%08x: %d\n", |
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ref_offset(fd->raw), ret); |
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return ret; |
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} |
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if (readlen != sizeof(*ri)) { |
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jffs2_free_raw_inode(ri); |
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pr_warn("Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n", |
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ref_offset(fd->raw), sizeof(*ri), readlen); |
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return -EIO; |
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} |
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crc = crc32(0, ri, sizeof(*ri)-8); |
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jffs2_dbg(1, "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n", |
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ref_offset(fd->raw), je32_to_cpu(ri->node_crc), |
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crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize), |
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je32_to_cpu(ri->offset), buf); |
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if (crc != je32_to_cpu(ri->node_crc)) { |
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pr_warn("Node CRC %08x != calculated CRC %08x for node at %08x\n", |
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je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw)); |
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ret = -EIO; |
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goto out_ri; |
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} |
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/* There was a bug where we wrote hole nodes out with csize/dsize |
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swapped. Deal with it */ |
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if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) && |
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je32_to_cpu(ri->csize)) { |
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ri->dsize = ri->csize; |
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ri->csize = cpu_to_je32(0); |
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} |
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D1(if(ofs + len > je32_to_cpu(ri->dsize)) { |
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pr_warn("jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n", |
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len, ofs, je32_to_cpu(ri->dsize)); |
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ret = -EINVAL; |
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goto out_ri; |
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}); |
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if (ri->compr == JFFS2_COMPR_ZERO) { |
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memset(buf, 0, len); |
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goto out_ri; |
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} |
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/* Cases: |
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Reading whole node and it's uncompressed - read directly to buffer provided, check CRC. |
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Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided |
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Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy |
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Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy |
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*/ |
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if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) { |
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readbuf = buf; |
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} else { |
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readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL); |
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if (!readbuf) { |
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ret = -ENOMEM; |
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goto out_ri; |
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} |
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} |
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if (ri->compr != JFFS2_COMPR_NONE) { |
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if (len < je32_to_cpu(ri->dsize)) { |
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decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL); |
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if (!decomprbuf) { |
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ret = -ENOMEM; |
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goto out_readbuf; |
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} |
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} else { |
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decomprbuf = buf; |
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} |
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} else { |
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decomprbuf = readbuf; |
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} |
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jffs2_dbg(2, "Read %d bytes to %p\n", je32_to_cpu(ri->csize), |
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readbuf); |
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ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri), |
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je32_to_cpu(ri->csize), &readlen, readbuf); |
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if (!ret && readlen != je32_to_cpu(ri->csize)) |
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ret = -EIO; |
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if (ret) |
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goto out_decomprbuf; |
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crc = crc32(0, readbuf, je32_to_cpu(ri->csize)); |
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if (crc != je32_to_cpu(ri->data_crc)) { |
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pr_warn("Data CRC %08x != calculated CRC %08x for node at %08x\n", |
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je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw)); |
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ret = -EIO; |
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goto out_decomprbuf; |
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} |
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jffs2_dbg(2, "Data CRC matches calculated CRC %08x\n", crc); |
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if (ri->compr != JFFS2_COMPR_NONE) { |
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jffs2_dbg(2, "Decompress %d bytes from %p to %d bytes at %p\n", |
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je32_to_cpu(ri->csize), readbuf, |
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je32_to_cpu(ri->dsize), decomprbuf); |
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ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize)); |
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if (ret) { |
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pr_warn("Error: jffs2_decompress returned %d\n", ret); |
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goto out_decomprbuf; |
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} |
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} |
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if (len < je32_to_cpu(ri->dsize)) { |
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memcpy(buf, decomprbuf+ofs, len); |
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} |
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out_decomprbuf: |
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if(decomprbuf != buf && decomprbuf != readbuf) |
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kfree(decomprbuf); |
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out_readbuf: |
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if(readbuf != buf) |
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kfree(readbuf); |
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out_ri: |
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jffs2_free_raw_inode(ri); |
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return ret; |
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} |
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int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f, |
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unsigned char *buf, uint32_t offset, uint32_t len) |
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{ |
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uint32_t end = offset + len; |
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struct jffs2_node_frag *frag; |
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int ret; |
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jffs2_dbg(1, "%s(): ino #%u, range 0x%08x-0x%08x\n", |
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__func__, f->inocache->ino, offset, offset + len); |
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frag = jffs2_lookup_node_frag(&f->fragtree, offset); |
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/* XXX FIXME: Where a single physical node actually shows up in two |
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frags, we read it twice. Don't do that. */ |
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/* Now we're pointing at the first frag which overlaps our page |
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* (or perhaps is before it, if we've been asked to read off the |
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* end of the file). */ |
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while(offset < end) { |
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jffs2_dbg(2, "%s(): offset %d, end %d\n", |
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__func__, offset, end); |
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if (unlikely(!frag || frag->ofs > offset || |
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frag->ofs + frag->size <= offset)) { |
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uint32_t holesize = end - offset; |
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if (frag && frag->ofs > offset) { |
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jffs2_dbg(1, "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", |
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f->inocache->ino, frag->ofs, offset); |
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holesize = min(holesize, frag->ofs - offset); |
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} |
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jffs2_dbg(1, "Filling non-frag hole from %d-%d\n", |
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offset, offset + holesize); |
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memset(buf, 0, holesize); |
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buf += holesize; |
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offset += holesize; |
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continue; |
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} else if (unlikely(!frag->node)) { |
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uint32_t holeend = min(end, frag->ofs + frag->size); |
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jffs2_dbg(1, "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", |
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offset, holeend, frag->ofs, |
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frag->ofs + frag->size); |
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memset(buf, 0, holeend - offset); |
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buf += holeend - offset; |
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offset = holeend; |
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frag = frag_next(frag); |
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continue; |
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} else { |
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uint32_t readlen; |
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uint32_t fragofs; /* offset within the frag to start reading */ |
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fragofs = offset - frag->ofs; |
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readlen = min(frag->size - fragofs, end - offset); |
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jffs2_dbg(1, "Reading %d-%d from node at 0x%08x (%d)\n", |
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frag->ofs+fragofs, |
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frag->ofs + fragofs+readlen, |
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ref_offset(frag->node->raw), |
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ref_flags(frag->node->raw)); |
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ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen); |
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jffs2_dbg(2, "node read done\n"); |
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if (ret) { |
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jffs2_dbg(1, "%s(): error %d\n", |
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__func__, ret); |
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memset(buf, 0, readlen); |
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return ret; |
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} |
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buf += readlen; |
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offset += readlen; |
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frag = frag_next(frag); |
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jffs2_dbg(2, "node read was OK. Looping\n"); |
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} |
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} |
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return 0; |
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} |
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