/*
|
* Copyright (C) 2014 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 __ANDROID_DLEXT_H__
|
#define __ANDROID_DLEXT_H__
|
|
#include <stdbool.h>
|
#include <stddef.h>
|
#include <stdint.h>
|
#include <sys/cdefs.h>
|
#include <sys/types.h> /* for off64_t */
|
|
/**
|
* @addtogroup libdl Dynamic Linker
|
* @{
|
*/
|
|
/**
|
* \file
|
* Advanced dynamic library opening support. Most users will want to use
|
* the standard [dlopen(3)](http://man7.org/linux/man-pages/man3/dlopen.3.html)
|
* functionality in `<dlfcn.h>` instead.
|
*/
|
|
__BEGIN_DECLS
|
|
/** Bitfield definitions for `android_dlextinfo::flags`. */
|
enum {
|
/**
|
* When set, the `reserved_addr` and `reserved_size` fields must point to an
|
* already-reserved region of address space which will be used to load the
|
* library if it fits.
|
*
|
* If the reserved region is not large enough, loading will fail.
|
*/
|
ANDROID_DLEXT_RESERVED_ADDRESS = 0x1,
|
|
/**
|
* Like `ANDROID_DLEXT_RESERVED_ADDRESS`, but if the reserved region is not large enough,
|
* the linker will choose an available address instead.
|
*/
|
ANDROID_DLEXT_RESERVED_ADDRESS_HINT = 0x2,
|
|
/**
|
* When set, write the GNU RELRO section of the mapped library to `relro_fd`
|
* after relocation has been performed, to allow it to be reused by another
|
* process loading the same library at the same address. This implies
|
* `ANDROID_DLEXT_USE_RELRO`.
|
*
|
* This is mainly useful for the system WebView implementation.
|
*/
|
ANDROID_DLEXT_WRITE_RELRO = 0x4,
|
|
/**
|
* When set, compare the GNU RELRO section of the mapped library to `relro_fd`
|
* after relocation has been performed, and replace any relocated pages that
|
* are identical with a version mapped from the file.
|
*
|
* This is mainly useful for the system WebView implementation.
|
*/
|
ANDROID_DLEXT_USE_RELRO = 0x8,
|
|
/**
|
* Use `library_fd` instead of opening the file by name.
|
* The filename parameter is still used to identify the library.
|
*/
|
ANDROID_DLEXT_USE_LIBRARY_FD = 0x10,
|
|
/**
|
* If opening a library using `library_fd` read it starting at `library_fd_offset`.
|
* This is mainly useful for loading a library stored within another file (such as uncompressed
|
* inside a ZIP archive).
|
* This flag is only valid when `ANDROID_DLEXT_USE_LIBRARY_FD` is set.
|
*/
|
ANDROID_DLEXT_USE_LIBRARY_FD_OFFSET = 0x20,
|
|
/**
|
* When set, do not use `stat(2)` to check if the library has already been loaded.
|
*
|
* This flag allows forced loading of the library in the case when for some
|
* reason multiple ELF files share the same filename (because the already-loaded
|
* library has been removed and overwritten, for example).
|
*
|
* Note that if the library has the same `DT_SONAME` as an old one and some other
|
* library has the soname in its `DT_NEEDED` list, the first one will be used to resolve any
|
* dependencies.
|
*/
|
ANDROID_DLEXT_FORCE_LOAD = 0x40,
|
|
// Historically we had two other options for ART.
|
// They were last available in Android P.
|
// Reuse these bits last!
|
// ANDROID_DLEXT_FORCE_FIXED_VADDR = 0x80
|
// ANDROID_DLEXT_LOAD_AT_FIXED_ADDRESS = 0x100
|
|
/**
|
* This flag used to load library in a different namespace. The namespace is
|
* specified in `library_namespace`.
|
*
|
* This flag is for internal use only (since there is no NDK API for namespaces).
|
*/
|
ANDROID_DLEXT_USE_NAMESPACE = 0x200,
|
|
/**
|
* Instructs dlopen to apply `ANDROID_DLEXT_RESERVED_ADDRESS`,
|
* `ANDROID_DLEXT_RESERVED_ADDRESS_HINT`, `ANDROID_DLEXT_WRITE_RELRO` and
|
* `ANDROID_DLEXT_USE_RELRO` to any libraries loaded as dependencies of the
|
* main library as well.
|
*
|
* This means that if the main library depends on one or more not-already-loaded libraries, they
|
* will be loaded consecutively into the region starting at `reserved_addr`, and `reserved_size`
|
* must be large enough to contain all of the libraries. The libraries will be loaded in the
|
* deterministic order constructed from the DT_NEEDED entries, rather than the more secure random
|
* order used by default.
|
*
|
* Each library's GNU RELRO sections will be written out to `relro_fd` in the same order they were
|
* loaded. This will mean that the resulting file is dependent on which of the libraries were
|
* already loaded, as only the newly loaded libraries will be included, not any already-loaded
|
* dependencies. The caller should ensure that the set of libraries newly loaded is consistent
|
* for this to be effective.
|
*
|
* This is mainly useful for the system WebView implementation.
|
*/
|
ANDROID_DLEXT_RESERVED_ADDRESS_RECURSIVE = 0x400,
|
|
|
/** Mask of valid bits. */
|
ANDROID_DLEXT_VALID_FLAG_BITS = ANDROID_DLEXT_RESERVED_ADDRESS |
|
ANDROID_DLEXT_RESERVED_ADDRESS_HINT |
|
ANDROID_DLEXT_WRITE_RELRO |
|
ANDROID_DLEXT_USE_RELRO |
|
ANDROID_DLEXT_USE_LIBRARY_FD |
|
ANDROID_DLEXT_USE_LIBRARY_FD_OFFSET |
|
ANDROID_DLEXT_FORCE_LOAD |
|
ANDROID_DLEXT_USE_NAMESPACE |
|
ANDROID_DLEXT_RESERVED_ADDRESS_RECURSIVE,
|
};
|
|
struct android_namespace_t;
|
|
/** Used to pass Android-specific arguments to `android_dlopen_ext`. */
|
typedef struct {
|
/** A bitmask of `ANDROID_DLEXT_` enum values. */
|
uint64_t flags;
|
|
/** Used by `ANDROID_DLEXT_RESERVED_ADDRESS` and `ANDROID_DLEXT_RESERVED_ADDRESS_HINT`. */
|
void* reserved_addr;
|
/** Used by `ANDROID_DLEXT_RESERVED_ADDRESS` and `ANDROID_DLEXT_RESERVED_ADDRESS_HINT`. */
|
size_t reserved_size;
|
|
/** Used by `ANDROID_DLEXT_WRITE_RELRO` and `ANDROID_DLEXT_USE_RELRO`. */
|
int relro_fd;
|
|
/** Used by `ANDROID_DLEXT_USE_LIBRARY_FD`. */
|
int library_fd;
|
/** Used by `ANDROID_DLEXT_USE_LIBRARY_FD_OFFSET` */
|
off64_t library_fd_offset;
|
|
/** Used by `ANDROID_DLEXT_USE_NAMESPACE`. */
|
struct android_namespace_t* library_namespace;
|
} android_dlextinfo;
|
|
/**
|
* Opens the given library. The `__filename` and `__flags` arguments are
|
* the same as for [dlopen(3)](http://man7.org/linux/man-pages/man3/dlopen.3.html),
|
* with the Android-specific flags supplied via the `flags` member of `__info`.
|
*
|
* Available since API level 21.
|
*/
|
void* android_dlopen_ext(const char* __filename, int __flags, const android_dlextinfo* __info)
|
__INTRODUCED_IN(21);
|
|
__END_DECLS
|
|
/** @} */
|
|
#endif
|
