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/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* Exports the kernel commandline from a given partition/image.
*/
#include "dump_kernel_config.h"
#include <stdio.h>
#include <sys/mman.h>
#include "host_common.h"
#include "kernel_blob.h"
uint8_t* find_kernel_config(uint8_t* blob, uint64_t blob_size,
uint64_t kernel_body_load_address) {
VbKeyBlockHeader* key_block;
VbKernelPreambleHeader* preamble;
struct linux_kernel_params *params;
uint32_t now = 0;
uint32_t offset = 0;
/* Skip the key block */
key_block = (VbKeyBlockHeader*)blob;
now += key_block->key_block_size;
if (now + blob > blob + blob_size) {
VbExError("key_block_size advances past the end of the blob\n");
return NULL;
}
/* Open up the preamble */
preamble = (VbKernelPreambleHeader*)(blob + now);
now += preamble->preamble_size;
if (now + blob > blob + blob_size) {
VbExError("preamble_size advances past the end of the blob\n");
return NULL;
}
/* The parameters are packed before the bootloader and there is no specific
* pointer to it so we just walk back by its allocated size. */
offset = preamble->bootloader_address -
(kernel_body_load_address + CROS_PARAMS_SIZE) + now;
if (offset > blob_size) {
VbExError("params are outside of the memory blob: %x\n", offset);
return NULL;
}
params = (struct linux_kernel_params *)(blob + offset);
/* Grab the offset to the kernel command line using the supplied pointer. */
offset = params->cmd_line_ptr - kernel_body_load_address + now;
if (offset > blob_size) {
VbExError("cmdline is outside of the memory blob: %x\n", offset);
return NULL;
}
return blob + offset;
}
void* MapFile(const char* filename, size_t *size) {
FILE* f;
uint8_t* buf;
long file_size = 0;
f = fopen(filename, "rb");
if (!f) {
VBDEBUG(("Unable to open file %s\n", filename));
return NULL;
}
fseek(f, 0, SEEK_END);
file_size = ftell(f);
rewind(f);
if (file_size <= 0) {
fclose(f);
return NULL;
}
*size = (size_t) file_size;
/* Uses a host primitive as this is not meant for firmware use. */
buf = mmap(NULL, *size, PROT_READ, MAP_PRIVATE, fileno(f), 0);
if (buf == MAP_FAILED) {
VbExError("Failed to mmap the file %s\n", filename);
fclose(f);
return NULL;
}
fclose(f);
return buf;
}
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