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/*
* Copyright (C) 2009 The Android Open Source Project
*
* 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 NATIVE_HANDLE_H_
#define NATIVE_HANDLE_H_
#include <stdalign.h>
#ifdef __cplusplus
extern "C" {
#endif
#define NATIVE_HANDLE_MAX_FDS 1024
#define NATIVE_HANDLE_MAX_INTS 1024
/* Declare a char array for use with native_handle_init */
#define NATIVE_HANDLE_DECLARE_STORAGE(name, maxFds, maxInts) \
alignas(native_handle_t) char (name)[ \
sizeof(native_handle_t) + sizeof(int) * ((maxFds) + (maxInts))]
typedef struct native_handle
{
int version; /* sizeof(native_handle_t) */
int numFds; /* number of file-descriptors at &data[0] */
int numInts; /* number of ints at &data[numFds] */
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wzero-length-array"
#endif
int data[0]; /* numFds + numInts ints */
#if defined(__clang__)
#pragma clang diagnostic pop
#endif
} native_handle_t;
typedef const native_handle_t* buffer_handle_t;
/*
* Closes the file descriptors contained in this native_handle_t, which may
* either be untagged or tagged for ownership by this native_handle_t via
* native_handle_set_tag(). Mixing untagged and tagged fds in the same
* native_handle_t is not permitted and triggers an fdsan exception, but
* native_handle_set_fdsan_tag() can be used to bring consistency if this is
* intentional.
*
* If it's known that fds are tagged, prefer native_handle_close_with_tag() for
* better safety.
*
* return 0 on success, or a negative error code on failure
*/
int native_handle_close(const native_handle_t* h);
/*
* Equivalent to native_handle_close(), but throws an fdsan exception if the fds
* are untagged. Use if it's known that the fds in this native_handle_t were
* previously tagged via native_handle_set_tag().
*/
int native_handle_close_with_tag(const native_handle_t* h);
/*
* Initializes a native_handle_t from storage. storage must be declared with
* NATIVE_HANDLE_DECLARE_STORAGE. numFds and numInts must not respectively
* exceed maxFds and maxInts used to declare the storage.
*/
native_handle_t* native_handle_init(char* storage, int numFds, int numInts);
/*
* Creates a native_handle_t and initializes it. Must be destroyed with
* native_handle_delete(). Note that numFds must be <= NATIVE_HANDLE_MAX_FDS,
* numInts must be <= NATIVE_HANDLE_MAX_INTS, and both must be >= 0.
*/
native_handle_t* native_handle_create(int numFds, int numInts);
/*
* Updates the fdsan tag for any file descriptors contained in the supplied
* handle to indicate that they are owned by this handle and should only be
* closed via native_handle_close()/native_handle_close_with_tag(). Each fd in
* the handle must have a tag of either 0 (unset) or the tag associated with
* this handle, otherwise an fdsan exception will be triggered.
*/
void native_handle_set_fdsan_tag(const native_handle_t* handle);
/*
* Clears the fdsan tag for any file descriptors contained in the supplied
* native_handle_t. Use if this native_handle_t is giving up ownership of its
* fds, but the fdsan tags were previously set. Each fd in the handle must have
* a tag of either 0 (unset) or the tag associated with this handle, otherwise
* an fdsan exception will be triggered.
*/
void native_handle_unset_fdsan_tag(const native_handle_t* handle);
/*
* Creates a native_handle_t and initializes it from another native_handle_t.
* Must be destroyed with native_handle_delete().
*/
native_handle_t* native_handle_clone(const native_handle_t* handle);
/*
* Frees a native_handle_t allocated with native_handle_create().
* This ONLY frees the memory allocated for the native_handle_t, but doesn't
* close the file descriptors; which can be achieved with native_handle_close().
*
* return 0 on success, or a negative error code on failure
*/
int native_handle_delete(native_handle_t* h);
#ifdef __cplusplus
}
#endif
#endif /* NATIVE_HANDLE_H_ */
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