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- /* SPDX-License-Identifier: MIT */
- /*
- * Copyright (C) 2016 The Android Open Source Project
- */
- #if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
- #error "Never include this file directly, include libavb.h instead."
- #endif
- #ifndef AVB_DESCRIPTOR_H_
- #define AVB_DESCRIPTOR_H_
- #include "avb_sysdeps.h"
- #ifdef __cplusplus
- extern "C" {
- #endif
- /* Well-known descriptor tags.
- *
- * AVB_DESCRIPTOR_TAG_PROPERTY: see |AvbPropertyDescriptor| struct.
- * AVB_DESCRIPTOR_TAG_HASHTREE: see |AvbHashtreeDescriptor| struct.
- * AVB_DESCRIPTOR_TAG_HASH: see |AvbHashDescriptor| struct.
- * AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE: see |AvbKernelCmdlineDescriptor| struct.
- * AVB_DESCRIPTOR_TAG_CHAIN_PARTITION: see |AvbChainPartitionDescriptor| struct.
- */
- typedef enum {
- AVB_DESCRIPTOR_TAG_PROPERTY,
- AVB_DESCRIPTOR_TAG_HASHTREE,
- AVB_DESCRIPTOR_TAG_HASH,
- AVB_DESCRIPTOR_TAG_KERNEL_CMDLINE,
- AVB_DESCRIPTOR_TAG_CHAIN_PARTITION,
- } AvbDescriptorTag;
- /* The header for a serialized descriptor.
- *
- * A descriptor always have two fields, a |tag| (denoting its type,
- * see the |AvbDescriptorTag| enumeration) and the size of the bytes
- * following, |num_bytes_following|.
- *
- * For padding, |num_bytes_following| is always a multiple of 8.
- */
- typedef struct AvbDescriptor {
- uint64_t tag;
- uint64_t num_bytes_following;
- } AVB_ATTR_PACKED AvbDescriptor;
- /* Copies |src| to |dest| and validates, byte-swapping fields in the
- * process if needed. Returns true if valid, false if invalid.
- *
- * Data following the struct is not validated nor copied.
- */
- bool avb_descriptor_validate_and_byteswap(
- const AvbDescriptor* src, AvbDescriptor* dest) AVB_ATTR_WARN_UNUSED_RESULT;
- /* Signature for callback function used in avb_descriptor_foreach().
- * The passed in descriptor is given by |descriptor| and the
- * |user_data| passed to avb_descriptor_foreach() function is in
- * |user_data|. Return true to continue iterating, false to stop
- * iterating.
- *
- * Note that |descriptor| points into the image passed to
- * avb_descriptor_foreach() - all fields need to be byteswapped!
- */
- typedef bool AvbDescriptorForeachFunc(const AvbDescriptor* descriptor,
- void* user_data);
- /* Convenience function to iterate over all descriptors in an vbmeta
- * image.
- *
- * The function given by |foreach_func| will be called for each
- * descriptor. The given function should return true to continue
- * iterating, false to stop.
- *
- * The |user_data| parameter will be passed to |foreach_func|.
- *
- * Returns false if the iteration was short-circuited, that is if
- * an invocation of |foreach_func| returned false.
- *
- * Before using this function, you MUST verify |image_data| with
- * avb_vbmeta_image_verify() and reject it unless it's signed by a known
- * good public key. Additionally, |image_data| must be word-aligned.
- */
- bool avb_descriptor_foreach(const uint8_t* image_data,
- size_t image_size,
- AvbDescriptorForeachFunc foreach_func,
- void* user_data);
- /* Gets all descriptors in a vbmeta image.
- *
- * The return value is a NULL-pointer terminated array of
- * AvbDescriptor pointers. Free with avb_free() when you are done with
- * it. If |out_num_descriptors| is non-NULL, the number of descriptors
- * will be returned there.
- *
- * Note that each AvbDescriptor pointer in the array points into
- * |image_data| - all fields need to be byteswapped!
- *
- * Before using this function, you MUST verify |image_data| with
- * avb_vbmeta_image_verify() and reject it unless it's signed by a known
- * good public key. Additionally, |image_data| must be word-aligned.
- */
- const AvbDescriptor** avb_descriptor_get_all(const uint8_t* image_data,
- size_t image_size,
- size_t* out_num_descriptors)
- AVB_ATTR_WARN_UNUSED_RESULT;
- #ifdef __cplusplus
- }
- #endif
- #endif /* AVB_DESCRIPTOR_H_ */
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