365 lines
11 KiB
C
365 lines
11 KiB
C
/*
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* This file is part of the libpayload project.
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*
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* Copyright (C) 2011 secunet Security Networks AG
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* Copyright (C) 2013 Google, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/* The CBFS core requires a couple of #defines or functions to adapt it to the
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* target environment:
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*
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* CBFS_CORE_WITH_LZMA (must be #define)
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* if defined, ulzma() must exist for decompression of data streams
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*
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* CBFS_CORE_WITH_LZ4 (must be #define)
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* if defined, ulz4f() must exist for decompression of data streams
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*
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* ERROR(x...)
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* print an error message x (in printf format)
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*
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* LOG(x...)
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* print a message x (in printf format)
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*
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* DEBUG(x...)
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* print a debug message x (in printf format)
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*
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*/
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#include <libpayload.h>
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#include <cbfs.h>
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#include <string.h>
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#include <sysinfo.h>
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/* returns a pointer to CBFS master header, or CBFS_HEADER_INVALID_ADDRESS
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* on failure */
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const struct cbfs_header *cbfs_get_header(struct cbfs_media *media)
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{
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int32_t rel_offset;
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const struct cbfs_header *header;
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struct cbfs_media default_media;
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if (media == CBFS_DEFAULT_MEDIA) {
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media = &default_media;
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if (init_default_cbfs_media(media) != 0) {
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ERROR("Failed to initialize default media.\n");
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return CBFS_HEADER_INVALID_ADDRESS;
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}
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}
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media->open(media);
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if (!media->read(media, &rel_offset, (size_t)(0 - sizeof(int32_t)),
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sizeof(int32_t))) {
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ERROR("Could not read CBFS master header offset!\n");
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return CBFS_HEADER_INVALID_ADDRESS;
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}
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header = media->map(media, (size_t)rel_offset, sizeof(*header));
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DEBUG("CBFS header at %#zx (-%#zx from end of image).\n",
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(size_t)rel_offset, (size_t)-rel_offset);
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media->close(media);
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if (header == CBFS_MEDIA_INVALID_MAP_ADDRESS) {
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ERROR("Failed to load CBFS header from %#zx(-%#zx)\n",
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(size_t)rel_offset, (size_t)-rel_offset);
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return CBFS_HEADER_INVALID_ADDRESS;
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}
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if (CBFS_HEADER_MAGIC != ntohl(header->magic)) {
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ERROR("Could not find valid CBFS master header at %#zx(-%#zx): "
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"magic %#.8x vs %#.8x.\n", (size_t)rel_offset,
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(size_t)-rel_offset, CBFS_HEADER_MAGIC,
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ntohl(header->magic));
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if (header->magic == 0xffffffff) {
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ERROR("Maybe ROM is not mapped properly?\n");
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}
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return CBFS_HEADER_INVALID_ADDRESS;
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}
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return header;
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}
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static int get_cbfs_range(uint32_t *offset, uint32_t *cbfs_end,
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struct cbfs_media *media)
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{
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const struct cbfs_header *header;
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if (media == CBFS_DEFAULT_MEDIA &&
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lib_sysinfo.cbfs_offset && lib_sysinfo.cbfs_size) {
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*offset = lib_sysinfo.cbfs_offset;
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*cbfs_end = *offset + lib_sysinfo.cbfs_size;
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return 0;
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}
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/* read offset and size from cbfs master header */
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DEBUG("Read CBFS offset & size from master header\n");
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header = cbfs_get_header(media);
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if (header == CBFS_HEADER_INVALID_ADDRESS)
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return -1;
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// Logical offset (for source media) of first file.
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*offset = ntohl(header->offset);
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*cbfs_end = ntohl(header->romsize);
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#if CONFIG(LP_ARCH_X86)
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// resolve actual length of ROM used for CBFS components
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// the bootblock size was not taken into account
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*cbfs_end -= ntohl(header->bootblocksize);
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// fine tune the length to handle alignment positioning.
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// using (bootblock size) % align, to derive the
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// number of bytes the bootblock is off from the alignment size.
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if ((ntohl(header->bootblocksize) % CBFS_ALIGNMENT))
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*cbfs_end -= (CBFS_ALIGNMENT -
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(ntohl(header->bootblocksize) % CBFS_ALIGNMENT));
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else
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*cbfs_end -= 1;
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#endif
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return 0;
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}
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/* public API starts here*/
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struct cbfs_handle *cbfs_get_handle(struct cbfs_media *media, const char *name)
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{
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const char *vardata;
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uint32_t offset, cbfs_end, vardata_len;
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struct cbfs_file file;
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struct cbfs_handle *handle = malloc(sizeof(*handle));
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if (!handle)
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return NULL;
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if (get_cbfs_range(&offset, &cbfs_end, media)) {
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ERROR("Failed to find cbfs range\n");
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free(handle);
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return NULL;
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}
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if (media == CBFS_DEFAULT_MEDIA) {
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media = &handle->media;
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if (init_default_cbfs_media(media) != 0) {
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ERROR("Failed to initialize default media.\n");
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free(handle);
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return NULL;
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}
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} else {
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memcpy(&handle->media, media, sizeof(*media));
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}
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DEBUG("CBFS location: 0x%x~0x%x\n", offset, cbfs_end);
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DEBUG("Looking for '%s' starting from 0x%x.\n", name, offset);
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media->open(media);
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while (offset < cbfs_end &&
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media->read(media, &file, offset, sizeof(file)) == sizeof(file)) {
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if (memcmp(CBFS_FILE_MAGIC, file.magic,
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sizeof(file.magic)) != 0) {
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uint32_t new_align = CBFS_ALIGNMENT;
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if (offset % CBFS_ALIGNMENT)
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new_align += CBFS_ALIGNMENT -
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(offset % CBFS_ALIGNMENT);
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ERROR("ERROR: No file header found at 0x%xx - "
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"try next aligned address: 0x%x.\n", offset,
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offset + new_align);
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offset += new_align;
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continue;
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}
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vardata_len = ntohl(file.offset) - sizeof(file);
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DEBUG(" - load entry 0x%x variable data (%d bytes)...\n",
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offset, vardata_len);
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// load file name (arbitrary length).
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vardata = (const char*)media->map(
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media, offset + sizeof(file), vardata_len);
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if (vardata == CBFS_MEDIA_INVALID_MAP_ADDRESS) {
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ERROR("ERROR: Failed to get filename: 0x%x.\n", offset);
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} else if (strcmp(vardata, name) == 0) {
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int file_offset = ntohl(file.offset),
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file_len = ntohl(file.len);
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DEBUG("Found file (offset=0x%x, len=%d).\n",
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offset + file_offset, file_len);
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media->unmap(media, vardata);
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media->close(media);
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handle->type = ntohl(file.type);
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handle->media_offset = offset;
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handle->content_offset = file_offset;
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handle->content_size = file_len;
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handle->attribute_offset =
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ntohl(file.attributes_offset);
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return handle;
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} else {
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DEBUG(" (unmatched file @0x%x: %s)\n", offset,
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vardata);
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media->unmap(media, vardata);
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}
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// Move to next file.
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uint32_t next_offset = offset + ntohl(file.len) + ntohl(file.offset);
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if (next_offset % CBFS_ALIGNMENT)
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next_offset += CBFS_ALIGNMENT - (next_offset % CBFS_ALIGNMENT);
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// Check that offset is strictly monotonic to prevent infinite loop
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if (next_offset <= offset) {
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ERROR("ERROR: corrupted CBFS file header at 0x%x.\n", offset);
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break;
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}
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offset = next_offset;
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}
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media->close(media);
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LOG("WARNING: '%s' not found.\n", name);
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free(handle);
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return NULL;
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}
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void *cbfs_get_contents(struct cbfs_handle *handle, size_t *size, size_t limit)
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{
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struct cbfs_media *m = &handle->media;
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size_t on_media_size = handle->content_size;
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int algo = CBFS_COMPRESS_NONE;
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void *ret = NULL;
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size_t dummy_size;
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if (!size)
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size = &dummy_size;
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struct cbfs_file_attr_compression *comp =
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cbfs_get_attr(handle, CBFS_FILE_ATTR_TAG_COMPRESSION);
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if (comp) {
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algo = ntohl(comp->compression);
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DEBUG("File '%s' is compressed (alg=%d)\n", name, algo);
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*size = ntohl(comp->decompressed_size);
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/* TODO: Implement partial decompression with |limit| */
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}
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if (algo == CBFS_COMPRESS_NONE) {
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if (limit != 0 && limit < on_media_size)
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on_media_size = limit;
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*size = on_media_size;
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}
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void *data = m->map(m, handle->media_offset + handle->content_offset,
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on_media_size);
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if (data == CBFS_MEDIA_INVALID_MAP_ADDRESS)
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return NULL;
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ret = malloc(*size);
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if (ret != NULL) {
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size_t final_size = cbfs_decompress(algo, data, on_media_size,
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ret, *size);
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if (final_size != *size) {
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ERROR("Expect %zu bytes but got %zu bytes after "
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"decompression.\n", *size, final_size);
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free(ret);
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ret = NULL;
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}
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}
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m->unmap(m, data);
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return ret;
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}
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void *cbfs_get_file_content(struct cbfs_media *media, const char *name,
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int type, size_t *sz)
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{
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void *ret = NULL;
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struct cbfs_handle *handle = cbfs_get_handle(media, name);
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if (!handle)
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return NULL;
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if (handle->type == type)
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ret = cbfs_get_contents(handle, sz, 0);
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else
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ERROR("File '%s' is of type %x, but we requested %x.\n", name,
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handle->type, type);
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free(handle);
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return ret;
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}
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void *cbfs_get_attr(struct cbfs_handle *handle, uint32_t tag)
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{
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struct cbfs_media *m = &handle->media;
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uint32_t offset = handle->media_offset + handle->attribute_offset;
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uint32_t end = handle->media_offset + handle->content_offset;
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struct cbfs_file_attribute attr;
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void *ret;
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/* attribute_offset should be 0 when there is no attribute, but all
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* values that point into the cbfs_file header are invalid, too. */
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if (handle->attribute_offset <= sizeof(struct cbfs_file))
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return NULL;
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m->open(m);
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while (offset + sizeof(attr) <= end) {
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if (m->read(m, &attr, offset, sizeof(attr)) != sizeof(attr)) {
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ERROR("Failed to read attribute header %#x\n", offset);
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m->close(m);
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return NULL;
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}
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if (ntohl(attr.tag) != tag) {
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uint32_t next_offset = offset + ntohl(attr.len);
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// Check that offset is strictly monotonic to prevent infinite loop
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if (next_offset <= offset) {
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ERROR("ERROR: corrupted CBFS attribute at 0x%x.\n", offset);
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m->close(m);
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return NULL;
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}
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offset = next_offset;
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continue;
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}
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ret = m->map(m, offset, ntohl(attr.len));
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if (ret == CBFS_MEDIA_INVALID_MAP_ADDRESS) {
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ERROR("Failed to map attribute at %#x\n", offset);
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m->close(m);
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return NULL;
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}
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return ret;
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}
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m->close(m);
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return NULL;
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}
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size_t cbfs_decompress(int algo, const void *src, size_t srcn, void *dst,
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size_t dstn)
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{
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size_t len;
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switch (algo) {
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case CBFS_COMPRESS_NONE:
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len = MIN(srcn, dstn);
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memcpy(dst, src, len);
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return len;
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#ifdef CBFS_CORE_WITH_LZMA
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case CBFS_COMPRESS_LZMA:
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return ulzman(src, srcn, dst, dstn);
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#endif
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#ifdef CBFS_CORE_WITH_LZ4
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case CBFS_COMPRESS_LZ4:
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return ulz4fn(src, srcn, dst, dstn);
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#endif
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default:
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ERROR("tried to decompress %zu bytes with algorithm "
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"#%x, but that algorithm id is unsupported.\n",
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srcn, algo);
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return 0;
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}
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}
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