text: /****************************************************************************
   *
   *   Copyright (c) 2020 Technology Innovation Institute. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name PX4 nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  #include "hw_config.h"
  
  #include <inttypes.h>
  #include <stdbool.h>
  #include <stddef.h>
  #include <string.h>
  
  #include "image_toc.h"
  
  #include "bl.h"
  
  /* Helper macros to define flash start and end addresses, based on info from
   * hw_config.h
   */
  #define FLASH_START_ADDRESS (APP_LOAD_ADDRESS & (~(BOARD_FLASH_SIZE - 1)))
  #define FLASH_END_ADDRESS (FLASH_START_ADDRESS + BOARD_FLASH_SIZE)
  
  bool find_toc(const image_toc_entry_t **toc_entries, uint8_t *len)
  {
  	const uintptr_t toc_start_u32 = APP_LOAD_ADDRESS + BOOT_DELAY_ADDRESS + 8;
  	const image_toc_start_t *toc_start = (const image_toc_start_t *)toc_start_u32;
  	const image_toc_entry_t *entry = (const image_toc_entry_t *)(toc_start_u32 + sizeof(image_toc_start_t));
  
  	int i = 0;
  	uint8_t sig_idx;
  	const uint32_t toc_end_magic = TOC_END_MAGIC;
  
  	if (toc_start->magic == TOC_START_MAGIC &&
  	    toc_start->version <= TOC_VERSION) {
  
  		/* Count the entries in TOC */
  		while (i < MAX_TOC_ENTRIES &&
  		       (uintptr_t)&entry[i] <= FLASH_END_ADDRESS - sizeof(uintptr_t) &&
  		       memcmp(&entry[i], &toc_end_magic, sizeof(toc_end_magic))) {
  			i++;
  		}
  
  		/* The number of toc entries found must be within bounds, and the
  		 * application has to lie within the flashable area. Also ensure that
  		 * end > start.
  		 */
  
  		if (i <= MAX_TOC_ENTRIES && i > 0 &&
  		    (uintptr_t)entry[0].start == APP_LOAD_ADDRESS &&
  		    (uintptr_t)entry[0].end <= (FLASH_END_ADDRESS - sizeof(uintptr_t)) &&
  		    (uintptr_t)entry[0].end > (uintptr_t)entry[0].start) {
  			sig_idx = entry[0].signature_idx;
  
  			/* The signature idx for the first app must be within the TOC, and
  			* the signature must be within the flash area, not overlapping the
  			* app. Also ensure that end > start.
  			*/
  
  			if (sig_idx > 0 &&
  			    sig_idx < MAX_TOC_ENTRIES &&
  			    (uintptr_t)entry[sig_idx].start >= (uintptr_t)entry[0].end &&
  			    (uintptr_t)entry[sig_idx].end <= FLASH_END_ADDRESS &&
  			    (uintptr_t)entry[sig_idx].end > (uintptr_t)entry[sig_idx].start) {
  				*toc_entries = entry;
  				*len = i;
  				return true;
  			}
  		}
  	}
  
  	*toc_entries = NULL;
  	*len = 0;
  	return false;
  }
  