/* * JFFS2 -- Journalling Flash File System, Version 2. * * Copyright (C) 2001 Red Hat, Inc. * * Created by David Woodhouse * * The original JFFS, from which the design for JFFS2 was derived, * was designed and implemented by Axis Communications AB. * * The contents of this file are subject to the Red Hat eCos Public * License Version 1.1 (the "Licence"); you may not use this file * except in compliance with the Licence. You may obtain a copy of * the Licence at http://www.redhat.com/ * * Software distributed under the Licence is distributed on an "AS IS" * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. * See the Licence for the specific language governing rights and * limitations under the Licence. * * The Original Code is JFFS2 - Journalling Flash File System, version 2 * * Alternatively, the contents of this file may be used under the * terms of the GNU General Public License version 2 (the "GPL"), in * which case the provisions of the GPL are applicable instead of the * above. If you wish to allow the use of your version of this file * only under the terms of the GPL and not to allow others to use your * version of this file under the RHEPL, indicate your decision by * deleting the provisions above and replace them with the notice and * other provisions required by the GPL. If you do not delete the * provisions above, a recipient may use your version of this file * under either the RHEPL or the GPL. * * $Id: read.c,v 1.13.2.1 2002/02/01 23:32:33 dwmw2 Exp $ * */ #include #include #include #include #include "nodelist.h" #include "crc32.h" int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_full_dnode *fd, unsigned char *buf, int ofs, int len) { struct jffs2_raw_inode *ri; size_t readlen; __u32 crc; unsigned char *decomprbuf = NULL; unsigned char *readbuf = NULL; int ret = 0; ri = jffs2_alloc_raw_inode(); if (!ri) return -ENOMEM; ret = c->mtd->read(c->mtd, fd->raw->flash_offset & ~3, sizeof(*ri), &readlen, (char *)ri); if (ret) { jffs2_free_raw_inode(ri); printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", fd->raw->flash_offset & ~3, ret); return ret; } if (readlen != sizeof(*ri)) { jffs2_free_raw_inode(ri); printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%x bytes, got 0x%x\n", fd->raw->flash_offset & ~3, 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", fd->raw->flash_offset & ~3, ri->node_crc, crc, ri->dsize, ri->csize, ri->offset, buf)); if (crc != ri->node_crc) { printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n", ri->node_crc, crc, fd->raw->flash_offset & ~3); 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 && !ri->dsize && ri->csize) { ri->dsize = ri->csize; ri->csize = 0; } D1(if(ofs + len > ri->dsize) { printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n", len, ofs, 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 == ri->dsize) { readbuf = buf; } else { readbuf = kmalloc(ri->csize, GFP_KERNEL); if (!readbuf) { ret = -ENOMEM; goto out_ri; } } if (ri->compr != JFFS2_COMPR_NONE) { if (len < ri->dsize) { decomprbuf = kmalloc(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", ri->csize, readbuf)); ret = c->mtd->read(c->mtd, (fd->raw->flash_offset &~3) + sizeof(*ri), ri->csize, &readlen, readbuf); if (!ret && readlen != ri->csize) ret = -EIO; if (ret) goto out_decomprbuf; crc = crc32(0, readbuf, ri->csize); if (crc != ri->data_crc) { printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n", ri->data_crc, crc, fd->raw->flash_offset & ~3); 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", ri->csize, readbuf, ri->dsize, decomprbuf)); ret = jffs2_decompress(ri->compr, readbuf, decomprbuf, ri->csize, ri->dsize); if (ret) { printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret); goto out_decomprbuf; } } if (len < 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; }