--- /dev/null
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_OPS_H_
+#define AVB_OPS_H_
+
+#include "avb_sysdeps.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Well-known names of named persistent values. */
+#define AVB_NPV_PERSISTENT_DIGEST_PREFIX "avb.persistent_digest."
+
+/* Return codes used for I/O operations.
+ *
+ * AVB_IO_RESULT_OK is returned if the requested operation was
+ * successful.
+ *
+ * AVB_IO_RESULT_ERROR_IO is returned if the underlying hardware (disk
+ * or other subsystem) encountered an I/O error.
+ *
+ * AVB_IO_RESULT_ERROR_OOM is returned if unable to allocate memory.
+ *
+ * AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION is returned if the requested
+ * partition does not exist.
+ *
+ * AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION is returned if the
+ * range of bytes requested to be read or written is outside the range
+ * of the partition.
+ *
+ * AVB_IO_RESULT_ERROR_NO_SUCH_VALUE is returned if a named persistent value
+ * does not exist.
+ *
+ * AVB_IO_RESULT_ERROR_INVALID_VALUE_SIZE is returned if a named persistent
+ * value size is not supported or does not match the expected size.
+ *
+ * AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE is returned if a buffer is too small
+ * for the requested operation.
+ */
+typedef enum {
+ AVB_IO_RESULT_OK,
+ AVB_IO_RESULT_ERROR_OOM,
+ AVB_IO_RESULT_ERROR_IO,
+ AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION,
+ AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION,
+ AVB_IO_RESULT_ERROR_NO_SUCH_VALUE,
+ AVB_IO_RESULT_ERROR_INVALID_VALUE_SIZE,
+ AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE,
+} AvbIOResult;
+
+struct AvbOps;
+typedef struct AvbOps AvbOps;
+
+/* Forward-declaration of operations in libavb_ab. */
+struct AvbABOps;
+
+/* Forward-declaration of operations in libavb_atx. */
+struct AvbAtxOps;
+
+/* High-level operations/functions/methods that are platform
+ * dependent.
+ *
+ * Operations may be added in the future so when implementing it
+ * always make sure to zero out sizeof(AvbOps) bytes of the struct to
+ * ensure that unimplemented operations are set to NULL.
+ */
+struct AvbOps {
+ /* This pointer can be used by the application/bootloader using
+ * libavb and is typically used in each operation to get a pointer
+ * to platform-specific resources. It cannot be used by libraries.
+ */
+ void* user_data;
+
+ /* If libavb_ab is used, this should point to the
+ * AvbABOps. Otherwise it must be set to NULL.
+ */
+ struct AvbABOps* ab_ops;
+
+ /* If libavb_atx is used, this should point to the
+ * AvbAtxOps. Otherwise it must be set to NULL.
+ */
+ struct AvbAtxOps* atx_ops;
+
+ /* Reads |num_bytes| from offset |offset| from partition with name
+ * |partition| (NUL-terminated UTF-8 string). If |offset| is
+ * negative, its absolute value should be interpreted as the number
+ * of bytes from the end of the partition.
+ *
+ * This function returns AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION if
+ * there is no partition with the given name,
+ * AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION if the requested
+ * |offset| is outside the partition, and AVB_IO_RESULT_ERROR_IO if
+ * there was an I/O error from the underlying I/O subsystem. If the
+ * operation succeeds as requested AVB_IO_RESULT_OK is returned and
+ * the data is available in |buffer|.
+ *
+ * The only time partial I/O may occur is if reading beyond the end
+ * of the partition. In this case the value returned in
+ * |out_num_read| may be smaller than |num_bytes|.
+ */
+ AvbIOResult (*read_from_partition)(AvbOps* ops,
+ const char* partition,
+ int64_t offset,
+ size_t num_bytes,
+ void* buffer,
+ size_t* out_num_read);
+
+ /* Gets the starting pointer of a partition that is pre-loaded in memory, and
+ * save it to |out_pointer|. The preloaded partition is expected to be
+ * |num_bytes|, where the actual preloaded byte count is returned in
+ * |out_num_bytes_preloaded|. |out_num_bytes_preloaded| must be no larger than
+ * |num_bytes|.
+ *
+ * This provides an alternative way to access a partition that is preloaded
+ * into memory without a full memory copy. When this function pointer is not
+ * set (has value NULL), or when the |out_pointer| is set to NULL as a result,
+ * |read_from_partition| will be used as the fallback. This function is mainly
+ * used for accessing the entire partition content to calculate its hash.
+ *
+ * Preloaded partition data must outlive the lifespan of the
+ * |AvbSlotVerifyData| structure that |avb_slot_verify| outputs.
+ */
+ AvbIOResult (*get_preloaded_partition)(AvbOps* ops,
+ const char* partition,
+ size_t num_bytes,
+ uint8_t** out_pointer,
+ size_t* out_num_bytes_preloaded);
+
+ /* Writes |num_bytes| from |bffer| at offset |offset| to partition
+ * with name |partition| (NUL-terminated UTF-8 string). If |offset|
+ * is negative, its absolute value should be interpreted as the
+ * number of bytes from the end of the partition.
+ *
+ * This function returns AVB_IO_RESULT_ERROR_NO_SUCH_PARTITION if
+ * there is no partition with the given name,
+ * AVB_IO_RESULT_ERROR_RANGE_OUTSIDE_PARTITION if the requested
+ * byterange goes outside the partition, and AVB_IO_RESULT_ERROR_IO
+ * if there was an I/O error from the underlying I/O subsystem. If
+ * the operation succeeds as requested AVB_IO_RESULT_OK is
+ * returned.
+ *
+ * This function never does any partial I/O, it either transfers all
+ * of the requested bytes or returns an error.
+ */
+ AvbIOResult (*write_to_partition)(AvbOps* ops,
+ const char* partition,
+ int64_t offset,
+ size_t num_bytes,
+ const void* buffer);
+
+ /* Checks if the given public key used to sign the 'vbmeta'
+ * partition is trusted. Boot loaders typically compare this with
+ * embedded key material generated with 'avbtool
+ * extract_public_key'.
+ *
+ * The public key is in the array pointed to by |public_key_data|
+ * and is of |public_key_length| bytes.
+ *
+ * If there is no public key metadata (set with the avbtool option
+ * --public_key_metadata) then |public_key_metadata| will be set to
+ * NULL. Otherwise this field points to the data which is
+ * |public_key_metadata_length| bytes long.
+ *
+ * If AVB_IO_RESULT_OK is returned then |out_is_trusted| is set -
+ * true if trusted or false if untrusted.
+ */
+ AvbIOResult (*validate_vbmeta_public_key)(AvbOps* ops,
+ const uint8_t* public_key_data,
+ size_t public_key_length,
+ const uint8_t* public_key_metadata,
+ size_t public_key_metadata_length,
+ bool* out_is_trusted);
+
+ /* Gets the rollback index corresponding to the location given by
+ * |rollback_index_location|. The value is returned in
+ * |out_rollback_index|. Returns AVB_IO_RESULT_OK if the rollback
+ * index was retrieved, otherwise an error code.
+ *
+ * A device may have a limited amount of rollback index locations (say,
+ * one or four) so may error out if |rollback_index_location| exceeds
+ * this number.
+ */
+ AvbIOResult (*read_rollback_index)(AvbOps* ops,
+ size_t rollback_index_location,
+ uint64_t* out_rollback_index);
+
+ /* Sets the rollback index corresponding to the location given by
+ * |rollback_index_location| to |rollback_index|. Returns
+ * AVB_IO_RESULT_OK if the rollback index was set, otherwise an
+ * error code.
+ *
+ * A device may have a limited amount of rollback index locations (say,
+ * one or four) so may error out if |rollback_index_location| exceeds
+ * this number.
+ */
+ AvbIOResult (*write_rollback_index)(AvbOps* ops,
+ size_t rollback_index_location,
+ uint64_t rollback_index);
+
+ /* Gets whether the device is unlocked. The value is returned in
+ * |out_is_unlocked| (true if unlocked, false otherwise). Returns
+ * AVB_IO_RESULT_OK if the state was retrieved, otherwise an error
+ * code.
+ */
+ AvbIOResult (*read_is_device_unlocked)(AvbOps* ops, bool* out_is_unlocked);
+
+ /* Gets the unique partition GUID for a partition with name in
+ * |partition| (NUL-terminated UTF-8 string). The GUID is copied as
+ * a string into |guid_buf| of size |guid_buf_size| and will be NUL
+ * terminated. The string must be lower-case and properly
+ * hyphenated. For example:
+ *
+ * 527c1c6d-6361-4593-8842-3c78fcd39219
+ *
+ * Returns AVB_IO_RESULT_OK on success, otherwise an error code.
+ */
+ AvbIOResult (*get_unique_guid_for_partition)(AvbOps* ops,
+ const char* partition,
+ char* guid_buf,
+ size_t guid_buf_size);
+
+ /* Gets the size of a partition with the name in |partition|
+ * (NUL-terminated UTF-8 string). Returns the value in
+ * |out_size_num_bytes|.
+ *
+ * Returns AVB_IO_RESULT_OK on success, otherwise an error code.
+ */
+ AvbIOResult (*get_size_of_partition)(AvbOps* ops,
+ const char* partition,
+ uint64_t* out_size_num_bytes);
+
+ /* Reads a persistent value corresponding to the given |name|. The value is
+ * returned in |out_buffer| which must point to |buffer_size| bytes. On
+ * success |out_num_bytes_read| contains the number of bytes read into
+ * |out_buffer|. If AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE is returned,
+ * |out_num_bytes_read| contains the number of bytes that would have been read
+ * which can be used to allocate a buffer.
+ *
+ * The |buffer_size| may be zero and the |out_buffer| may be NULL, but if
+ * |out_buffer| is NULL then |buffer_size| *must* be zero.
+ *
+ * Returns AVB_IO_RESULT_OK on success, otherwise an error code.
+ *
+ * If the value does not exist, is not supported, or is not populated, returns
+ * AVB_IO_RESULT_ERROR_NO_SUCH_VALUE. If |buffer_size| is smaller than the
+ * size of the stored value, returns AVB_IO_RESULT_ERROR_INSUFFICIENT_SPACE.
+ *
+ * This operation is currently only used to support persistent digests. If a
+ * device does not use persistent digests this function pointer can be set to
+ * NULL.
+ */
+ AvbIOResult (*read_persistent_value)(AvbOps* ops,
+ const char* name,
+ size_t buffer_size,
+ uint8_t* out_buffer,
+ size_t* out_num_bytes_read);
+
+ /* Writes a persistent value corresponding to the given |name|. The value is
+ * supplied in |value| which must point to |value_size| bytes. Any existing
+ * value with the same name is overwritten. If |value_size| is zero, future
+ * calls to |read_persistent_value| will return
+ * AVB_IO_RESULT_ERROR_NO_SUCH_VALUE.
+ *
+ * Returns AVB_IO_RESULT_OK on success, otherwise an error code.
+ *
+ * If the value |name| is not supported, returns
+ * AVB_IO_RESULT_ERROR_NO_SUCH_VALUE. If the |value_size| is not supported,
+ * returns AVB_IO_RESULT_ERROR_INVALID_VALUE_SIZE.
+ *
+ * This operation is currently only used to support persistent digests. If a
+ * device does not use persistent digests this function pointer can be set to
+ * NULL.
+ */
+ AvbIOResult (*write_persistent_value)(AvbOps* ops,
+ const char* name,
+ size_t value_size,
+ const uint8_t* value);
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_OPS_H_ */
projects / oweals / u-boot.git / blobdiff