text: // Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #ifndef _OTA_OPS_H
  #define _OTA_OPS_H
  
  #include <stdint.h>
  #include <stdbool.h>
  #include <stddef.h>
  #include "esp_err.h"
  #include "esp_partition.h"
  #include "esp_image_format.h"
  #include "esp_flash_partitions.h"
  
  #ifdef __cplusplus
  extern "C"
  {
  #endif
  
  #define OTA_SIZE_UNKNOWN 0xffffffff /*!< Used for esp_ota_begin() if new image size is unknown */
  
  #define ESP_ERR_OTA_BASE                         0x1500                     /*!< Base error code for ota_ops api */
  #define ESP_ERR_OTA_PARTITION_CONFLICT           (ESP_ERR_OTA_BASE + 0x01)  /*!< Error if request was to write or erase the current running partition */
  #define ESP_ERR_OTA_SELECT_INFO_INVALID          (ESP_ERR_OTA_BASE + 0x02)  /*!< Error if OTA data partition contains invalid content */
  #define ESP_ERR_OTA_VALIDATE_FAILED              (ESP_ERR_OTA_BASE + 0x03)  /*!< Error if OTA app image is invalid */
  #define ESP_ERR_OTA_SMALL_SEC_VER                (ESP_ERR_OTA_BASE + 0x04)  /*!< Error if the firmware has a secure version less than the running firmware. */
  #define ESP_ERR_OTA_ROLLBACK_FAILED              (ESP_ERR_OTA_BASE + 0x05)  /*!< Error if flash does not have valid firmware in passive partition and hence rollback is not possible */
  #define ESP_ERR_OTA_ROLLBACK_INVALID_STATE       (ESP_ERR_OTA_BASE + 0x06)  /*!< Error if current active firmware is still marked in pending validation state (ESP_OTA_IMG_PENDING_VERIFY), essentially first boot of firmware image post upgrade and hence firmware upgrade is not possible */
  
  
  /**
   * @brief Opaque handle for an application OTA update
   *
   * esp_ota_begin() returns a handle which is then used for subsequent
   * calls to esp_ota_write() and esp_ota_end().
   */
  typedef uint32_t esp_ota_handle_t;
  
  /**
   * @brief   Return esp_app_desc structure. This structure includes app version.
   *
   * Return description for running app.
   * @return Pointer to esp_app_desc structure.
   */
  const esp_app_desc_t *esp_ota_get_app_description(void);
  
  /**
   * @brief   Fill the provided buffer with SHA256 of the ELF file, formatted as hexadecimal, null-terminated.
   * If the buffer size is not sufficient to fit the entire SHA256 in hex plus a null terminator,
   * the largest possible number of bytes will be written followed by a null.
   * @param dst   Destination buffer
   * @param size  Size of the buffer
   * @return      Number of bytes written to dst (including null terminator)
   */
  int esp_ota_get_app_elf_sha256(char* dst, size_t size);
  
  /**
   * @brief   Commence an OTA update writing to the specified partition.
  
   * The specified partition is erased to the specified image size.
   *
   * If image size is not yet known, pass OTA_SIZE_UNKNOWN which will
   * cause the entire partition to be erased.
   *
   * On success, this function allocates memory that remains in use
   * until esp_ota_end() is called with the returned handle.
   *
   * Note: If the rollback option is enabled and the running application has the ESP_OTA_IMG_PENDING_VERIFY state then
   * it will lead to the ESP_ERR_OTA_ROLLBACK_INVALID_STATE error. Confirm the running app before to run download a new app,
   * use esp_ota_mark_app_valid_cancel_rollback() function for it (this should be done as early as possible when you first download a new application).
   *
   * @param partition Pointer to info for partition which will receive the OTA update. Required.
   * @param image_size Size of new OTA app image. Partition will be erased in order to receive this size of image. If 0 or OTA_SIZE_UNKNOWN, the entire partition is erased.
   * @param out_handle On success, returns a handle which should be used for subsequent esp_ota_write() and esp_ota_end() calls.
  
   * @return
   *    - ESP_OK: OTA operation commenced successfully.
   *    - ESP_ERR_INVALID_ARG: partition or out_handle arguments were NULL, or partition doesn't point to an OTA app partition.
   *    - ESP_ERR_NO_MEM: Cannot allocate memory for OTA operation.
   *    - ESP_ERR_OTA_PARTITION_CONFLICT: Partition holds the currently running firmware, cannot update in place.
   *    - ESP_ERR_NOT_FOUND: Partition argument not found in partition table.
   *    - ESP_ERR_OTA_SELECT_INFO_INVALID: The OTA data partition contains invalid data.
   *    - ESP_ERR_INVALID_SIZE: Partition doesn't fit in configured flash size.
   *    - ESP_ERR_FLASH_OP_TIMEOUT or ESP_ERR_FLASH_OP_FAIL: Flash write failed.
   *    - ESP_ERR_OTA_ROLLBACK_INVALID_STATE: If the running app has not confirmed state. Before performing an update, the application must be valid.
   */
  esp_err_t esp_ota_begin(const esp_partition_t* partition, size_t image_size, esp_ota_handle_t* out_handle);
  
  /**
   * @brief   Write OTA update data to partition
   *
   * This function can be called multiple times as
   * data is received during the OTA operation. Data is written
   * sequentially to the partition.
   *
   * @param handle  Handle obtained from esp_ota_begin
   * @param data    Data buffer to write
   * @param size    Size of data buffer in bytes.
   *
   * @return
   *    - ESP_OK: Data was written to flash successfully.
   *    - ESP_ERR_INVALID_ARG: handle is invalid.
   *    - ESP_ERR_OTA_VALIDATE_FAILED: First byte of image contains invalid app image magic byte.
   *    - ESP_ERR_FLASH_OP_TIMEOUT or ESP_ERR_FLASH_OP_FAIL: Flash write failed.
   *    - ESP_ERR_OTA_SELECT_INFO_INVALID: OTA data partition has invalid contents
   */
  esp_err_t esp_ota_write(esp_ota_handle_t handle, const void* data, size_t size);
  
  /**
   * @brief   Write OTA update data to partition
   *
   * This function can write data in non contiguous manner.
   * If flash encryption is enabled, data should be 16 byte aligned.
   *
   * @param handle  Handle obtained from esp_ota_begin
   * @param data    Data buffer to write
   * @param size    Size of data buffer in bytes
   * @param offset  Offset in flash partition
   *
   * @note While performing OTA, if the packets arrive out of order, esp_ota_write_with_offset() can be used to write data in non contiguous manner.
   *       Use of esp_ota_write_with_offset() in combination with esp_ota_write() is not recommended.
   *
   * @return
   *    - ESP_OK: Data was written to flash successfully.
   *    - ESP_ERR_INVALID_ARG: handle is invalid.
   *    - ESP_ERR_OTA_VALIDATE_FAILED: First byte of image contains invalid app image magic byte.
   *    - ESP_ERR_FLASH_OP_TIMEOUT or ESP_ERR_FLASH_OP_FAIL: Flash write failed.
   *    - ESP_ERR_OTA_SELECT_INFO_INVALID: OTA data partition has invalid contents
   */
  esp_err_t esp_ota_write_with_offset(esp_ota_handle_t handle, const void *data, size_t size, uint32_t offset);
  
  /**
   * @brief Finish OTA update and validate newly written app image.
   *
   * @param handle  Handle obtained from esp_ota_begin().
   *
   * @note After calling esp_ota_end(), the handle is no longer valid and any memory associated with it is freed (regardless of result).
   *
   * @return
   *    - ESP_OK: Newly written OTA app image is valid.
   *    - ESP_ERR_NOT_FOUND: OTA handle was not found.
   *    - ESP_ERR_INVALID_ARG: Handle was never written to.
   *    - ESP_ERR_OTA_VALIDATE_FAILED: OTA image is invalid (either not a valid app image, or - if secure boot is enabled - signature failed to verify.)
   *    - ESP_ERR_INVALID_STATE: If flash encryption is enabled, this result indicates an internal error writing the final encrypted bytes to flash.
   */
  esp_err_t esp_ota_end(esp_ota_handle_t handle);
  
  /**
   * @brief Configure OTA data for a new boot partition
   *
   * @note If this function returns ESP_OK, calling esp_restart() will boot the newly configured app partition.
   *
   * @param partition Pointer to info for partition containing app image to boot.
   *
   * @return
   *    - ESP_OK: OTA data updated, next reboot will use specified partition.
   *    - ESP_ERR_INVALID_ARG: partition argument was NULL or didn't point to a valid OTA partition of type "app".
   *    - ESP_ERR_OTA_VALIDATE_FAILED: Partition contained invalid app image. Also returned if secure boot is enabled and signature validation failed.
   *    - ESP_ERR_NOT_FOUND: OTA data partition not found.
   *    - ESP_ERR_FLASH_OP_TIMEOUT or ESP_ERR_FLASH_OP_FAIL: Flash erase or write failed.
   */
  esp_err_t esp_ota_set_boot_partition(const esp_partition_t* partition);
  
  /**
   * @brief Get partition info of currently configured boot app
   *
   * If esp_ota_set_boot_partition() has been called, the partition which was set by that function will be returned.
   *
   * If esp_ota_set_boot_partition() has not been called, the result is usually the same as esp_ota_get_running_partition().
   * The two results are not equal if the configured boot partition does not contain a valid app (meaning that the running partition
   * will be an app that the bootloader chose via fallback).
   *
   * If the OTA data partition is not present or not valid then the result is the first app partition found in the
   * partition table. In priority order, this means: the factory app, the first OTA app slot, or the test app partition.
   *
   * Note that there is no guarantee the returned partition is a valid app. Use esp_image_verify(ESP_IMAGE_VERIFY, ...) to verify if the
   * returned partition contains a bootable image.
   *
   * @return Pointer to info for partition structure, or NULL if partition table is invalid or a flash read operation failed. Any returned pointer is valid for the lifetime of the application.
   */
  const esp_partition_t* esp_ota_get_boot_partition(void);
  
  
  /**
   * @brief Get partition info of currently running app
   *
   * This function is different to esp_ota_get_boot_partition() in that
   * it ignores any change of selected boot partition caused by
   * esp_ota_set_boot_partition(). Only the app whose code is currently
   * running will have its partition information returned.
   *
   * The partition returned by this function may also differ from esp_ota_get_boot_partition() if the configured boot
   * partition is somehow invalid, and the bootloader fell back to a different app partition at boot.
   *
   * @return Pointer to info for partition structure, or NULL if no partition is found or flash read operation failed. Returned pointer is valid for the lifetime of the application.
   */
  const esp_partition_t* esp_ota_get_running_partition(void);
  
  
  /**
   * @brief Return the next OTA app partition which should be written with a new firmware.
   *
   * Call this function to find an OTA app partition which can be passed to esp_ota_begin().
   *
   * Finds next partition round-robin, starting from the current running partition.
   *
   * @param start_from If set, treat this partition info as describing the current running partition. Can be NULL, in which case esp_ota_get_running_partition() is used to find the currently running partition. The result of this function is never the same as this argument.
   *
   * @return Pointer to info for partition which should be updated next. NULL result indicates invalid OTA data partition, or that no eligible OTA app slot partition was found.
   *
   */
  const esp_partition_t* esp_ota_get_next_update_partition(const esp_partition_t *start_from);
  
  /**
   * @brief Returns esp_app_desc structure for app partition. This structure includes app version.
   *
   * Returns a description for the requested app partition.
   * @param[in] partition     Pointer to app partition. (only app partition)
   * @param[out] app_desc     Structure of info about app.
   * @return
   *  - ESP_OK                Successful.
   *  - ESP_ERR_NOT_FOUND     app_desc structure is not found. Magic word is incorrect.
   *  - ESP_ERR_NOT_SUPPORTED Partition is not application.
   *  - ESP_ERR_INVALID_ARG   Arguments is NULL or if partition's offset exceeds partition size.
   *  - ESP_ERR_INVALID_SIZE  Read would go out of bounds of the partition.
   *  - or one of error codes from lower-level flash driver.
   */
  esp_err_t esp_ota_get_partition_description(const esp_partition_t *partition, esp_app_desc_t *app_desc);
  
  #if 0
  /**
   * @brief This function is called to indicate that the running app is working well.
   *
   * @return
   *  - ESP_OK: if successful.
   */
  esp_err_t esp_ota_mark_app_valid_cancel_rollback(void);
  
  /**
   * @brief This function is called to roll back to the previously workable app with reboot.
   *
   * If rollback is successful then device will reset else API will return with error code.
   * Checks applications on a flash drive that can be booted in case of rollback.
   * If the flash does not have at least one app (except the running app) then rollback is not possible.
   * @return
   *  - ESP_FAIL: if not successful.
   *  - ESP_ERR_OTA_ROLLBACK_FAILED: The rollback is not possible due to flash does not have any apps.
   */
  esp_err_t esp_ota_mark_app_invalid_rollback_and_reboot(void);
  
  /**
   * @brief Returns last partition with invalid state (ESP_OTA_IMG_INVALID or ESP_OTA_IMG_ABORTED).
   *
   * @return partition.
   */
  const esp_partition_t* esp_ota_get_last_invalid_partition(void);
  
  /**
   * @brief Returns state for given partition.
   *
   * @param[in] partition  Pointer to partition.
   * @param[out] ota_state state of partition (if this partition has a record in otadata).
   * @return
   *        - ESP_OK:                 Successful.
   *        - ESP_ERR_INVALID_ARG:    partition or ota_state arguments were NULL.
   *        - ESP_ERR_NOT_SUPPORTED:  partition is not ota.
   *        - ESP_ERR_NOT_FOUND:      Partition table does not have otadata or state was not found for given partition.
   */
  esp_err_t esp_ota_get_state_partition(const esp_partition_t *partition, esp_ota_img_states_t *ota_state);
  
  /**
   * @brief Erase previous boot app partition and corresponding otadata select for this partition.
   *
   * When current app is marked to as valid then you can erase previous app partition.
   * @return
   *        - ESP_OK:   Successful, otherwise ESP_ERR.
   */
  esp_err_t esp_ota_erase_last_boot_app_partition(void);
  
  /**
   * @brief Checks applications on the slots which can be booted in case of rollback.
   *
   * These applications should be valid (marked in otadata as not UNDEFINED, INVALID or ABORTED and crc is good) and be able booted,
   * and secure_version of app >= secure_version of efuse (if anti-rollback is enabled).
   *
   * @return
   *        - True: Returns true if the slots have at least one app (except the running app).
   *        - False: The rollback is not possible.
   */
  bool esp_ota_check_rollback_is_possible(void);
  #endif
  
  #if CONFIG_IDF_TARGET_ESP32S2 && (CONFIG_SECURE_BOOT_V2_ENABLED || __DOXYGEN__)
  
  /**
   * Secure Boot V2 public key indexes.
   */
  typedef enum {
      SECURE_BOOT_PUBLIC_KEY_INDEX_0,     /*!< Points to the 0th index of the Secure Boot v2 public key */
      SECURE_BOOT_PUBLIC_KEY_INDEX_1,     /*!< Points to the 1st index of the Secure Boot v2 public key */
      SECURE_BOOT_PUBLIC_KEY_INDEX_2      /*!< Points to the 2nd index of the Secure Boot v2 public key */
  } esp_ota_secure_boot_public_key_index_t;
  
  /**
   * @brief Revokes the old signature digest. To be called in the application after the rollback logic.
   *
   * Relevant for Secure boot v2 on ESP32-S2 where upto 3 key digests can be stored (Key N-1, Key N, Key N+1).
   * When key N-1 used to sign an app is invalidated, an OTA update is to be sent with an app signed with key N-1 & Key N.
   * After successfully booting the OTA app should call this function to revoke Key N-1.
   *
   * @param index - The index of the signature block to be revoked
   *
   * @return
   *        - ESP_OK: If revocation is successful.
   *        - ESP_ERR_INVALID_ARG: If the index of the public key to be revoked is incorrect.
   *        - ESP_FAIL: If secure boot v2 has not been enabled.
   */
  esp_err_t esp_ota_revoke_secure_boot_public_key(esp_ota_secure_boot_public_key_index_t index);
  #endif /* CONFIG_IDF_TARGET_ESP32S2 */
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* OTA_OPS_H */
  