315 lines
9.4 KiB
C
315 lines
9.4 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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* 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 <cbfs.h>
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#include <string.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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/* public API starts here*/
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struct cbfs_file *cbfs_get_file(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, romsize, vardata_len;
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const struct cbfs_header *header;
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struct cbfs_file file, *file_ptr;
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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 NULL;
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}
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}
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if (CBFS_HEADER_INVALID_ADDRESS == (header = cbfs_get_header(media)))
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return NULL;
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// Logical offset (for source media) of first file.
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offset = ntohl(header->offset);
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romsize = ntohl(header->romsize);
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// TODO Add a "size" in CBFS header for a platform independent way to
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// determine the end of CBFS data.
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#if IS_ENABLED(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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romsize -= 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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romsize -= (CBFS_ALIGNMENT -
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(ntohl(header->bootblocksize) % CBFS_ALIGNMENT));
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else
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romsize -= 1;
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#endif
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DEBUG("CBFS location: 0x%x~0x%x\n", offset, romsize);
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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 < romsize &&
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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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file_ptr = media->map(media, offset,
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file_offset + file_len);
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media->close(media);
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return file_ptr;
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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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offset += ntohl(file.len) + ntohl(file.offset);
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if (offset % CBFS_ALIGNMENT)
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offset += CBFS_ALIGNMENT - (offset % CBFS_ALIGNMENT);
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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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return NULL;
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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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struct cbfs_file *file = cbfs_get_file(media, name);
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if (sz)
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*sz = 0;
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if (file == NULL) {
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ERROR("Could not find file '%s'.\n", name);
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return NULL;
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}
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if (ntohl(file->type) != type) {
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ERROR("File '%s' is of type %x, but we requested %x.\n", name,
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ntohl(file->type), type);
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return NULL;
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}
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if (sz)
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*sz = ntohl(file->len);
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void *file_content = (void *)CBFS_SUBHEADER(file);
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struct cbfs_file_attribute *attr =
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cbfs_file_find_attr(file, CBFS_FILE_ATTR_TAG_COMPRESSION);
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int compression_algo = CBFS_COMPRESS_NONE;
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if (attr) {
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struct cbfs_file_attr_compression *comp =
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(struct cbfs_file_attr_compression *)attr;
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compression_algo = ntohl(comp->compression);
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DEBUG("File '%s' is compressed (alg=%d)\n",
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name, compression_algo);
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*sz = ntohl(comp->decompressed_size);
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}
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void *dst = malloc(*sz);
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if (dst == NULL)
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goto err;
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if (!cbfs_decompress(compression_algo, file_content, dst, *sz))
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goto err;
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media->unmap(media, file);
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return dst;
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err:
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media->unmap(media, file);
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free(dst);
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return NULL;
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}
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struct cbfs_file_attribute *cbfs_file_first_attr(struct cbfs_file *file)
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{
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/* attributes_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 (ntohl(file->attributes_offset) <= sizeof(*file))
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return NULL;
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/* There needs to be enough space for the file header and one
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* attribute header for this to make sense. */
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if (ntohl(file->offset) <=
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sizeof(*file) + sizeof(struct cbfs_file_attribute))
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return NULL;
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return (struct cbfs_file_attribute *)
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(((uint8_t *)file) + ntohl(file->attributes_offset));
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}
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struct cbfs_file_attribute *cbfs_file_next_attr(struct cbfs_file *file,
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struct cbfs_file_attribute *attr)
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{
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/* ex falso sequitur quodlibet */
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if (attr == NULL)
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return NULL;
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/* Is there enough space for another attribute? */
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if ((uint8_t *)attr + ntohl(attr->len) +
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sizeof(struct cbfs_file_attribute) >=
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(uint8_t *)file + ntohl(file->offset))
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return NULL;
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struct cbfs_file_attribute *next = (struct cbfs_file_attribute *)
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(((uint8_t *)attr) + ntohl(attr->len));
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/* If any, "unused" attributes must come last. */
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if (ntohl(next->tag) == CBFS_FILE_ATTR_TAG_UNUSED)
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return NULL;
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if (ntohl(next->tag) == CBFS_FILE_ATTR_TAG_UNUSED2)
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return NULL;
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return next;
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}
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struct cbfs_file_attribute *cbfs_file_find_attr(struct cbfs_file *file,
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uint32_t tag)
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{
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struct cbfs_file_attribute *attr = cbfs_file_first_attr(file);
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while (attr) {
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if (ntohl(attr->tag) == tag)
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break;
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attr = cbfs_file_next_attr(file, attr);
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}
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return attr;
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}
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int cbfs_decompress(int algo, void *src, void *dst, int len)
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{
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switch (algo) {
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case CBFS_COMPRESS_NONE:
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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 ulzma(src, dst);
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#endif
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default:
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ERROR("tried to decompress %d bytes with algorithm #%x,"
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"but that algorithm id is unsupported.\n", len,
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algo);
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return 0;
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}
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}
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