200 lines
8.7 KiB
C
200 lines
8.7 KiB
C
/*
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* Copyright (C) 2014 The Android Open Source Project
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef __ANDROID_DLEXT_H__
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#define __ANDROID_DLEXT_H__
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <sys/cdefs.h>
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#include <sys/types.h> /* for off64_t */
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__BEGIN_DECLS
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/* bitfield definitions for android_dlextinfo.flags */
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enum {
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/* When set, the reserved_addr and reserved_size fields must point to an
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* already-reserved region of address space which will be used to load the
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* library if it fits. If the reserved region is not large enough, the load
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* will fail.
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*/
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ANDROID_DLEXT_RESERVED_ADDRESS = 0x1,
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/* As DLEXT_RESERVED_ADDRESS, but if the reserved region is not large enough,
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* the linker will choose an available address instead.
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*/
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ANDROID_DLEXT_RESERVED_ADDRESS_HINT = 0x2,
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/* When set, write the GNU RELRO section of the mapped library to relro_fd
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* after relocation has been performed, to allow it to be reused by another
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* process loading the same library at the same address. This implies
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* ANDROID_DLEXT_USE_RELRO.
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*/
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ANDROID_DLEXT_WRITE_RELRO = 0x4,
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/* When set, compare the GNU RELRO section of the mapped library to relro_fd
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* after relocation has been performed, and replace any relocated pages that
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* are identical with a version mapped from the file.
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*/
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ANDROID_DLEXT_USE_RELRO = 0x8,
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/* Instruct dlopen to use library_fd instead of opening file by name.
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* The filename parameter is still used to identify the library.
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*/
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ANDROID_DLEXT_USE_LIBRARY_FD = 0x10,
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/* If opening a library using library_fd read it starting at library_fd_offset.
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* This flag is only valid when ANDROID_DLEXT_USE_LIBRARY_FD is set.
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*/
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ANDROID_DLEXT_USE_LIBRARY_FD_OFFSET = 0x20,
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/* When set, do not check if the library has already been loaded by file stat(2)s.
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*
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* This flag allows forced loading of the library in the case when for some
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* reason multiple ELF files share the same filename (because the already-loaded
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* library has been removed and overwritten, for example).
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*
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* Note that if the library has the same dt_soname as an old one and some other
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* library has the soname in DT_NEEDED list, the first one will be used to resolve any
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* dependencies.
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*/
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ANDROID_DLEXT_FORCE_LOAD = 0x40,
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/* When set, if the minimum p_vaddr of the ELF file's PT_LOAD segments is non-zero,
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* the dynamic linker will load it at that address.
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*
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* This flag is for ART internal use only.
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*/
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ANDROID_DLEXT_FORCE_FIXED_VADDR = 0x80,
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/* Instructs dlopen to load the library at the address specified by reserved_addr.
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*
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* The difference between ANDROID_DLEXT_LOAD_AT_FIXED_ADDRESS and ANDROID_DLEXT_RESERVED_ADDRESS
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* is that for ANDROID_DLEXT_LOAD_AT_FIXED_ADDRESS the linker reserves memory at reserved_addr
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* whereas for ANDROID_DLEXT_RESERVED_ADDRESS the linker relies on the caller to reserve the memory.
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*
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* This flag can be used with ANDROID_DLEXT_FORCE_FIXED_VADDR; when ANDROID_DLEXT_FORCE_FIXED_VADDR
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* is set and load_bias is not 0 (load_bias is min(p_vaddr) of PT_LOAD segments) this flag is ignored.
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* This is implemented this way because the linker has to pick one address over the other and this
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* way is more convenient for art. Note that ANDROID_DLEXT_FORCE_FIXED_VADDR does not generate
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* an error when min(p_vaddr) is 0.
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*
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* Cannot be used with ANDROID_DLEXT_RESERVED_ADDRESS or ANDROID_DLEXT_RESERVED_ADDRESS_HINT.
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*
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* This flag is for ART internal use only.
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*/
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ANDROID_DLEXT_LOAD_AT_FIXED_ADDRESS = 0x100,
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/* This flag used to load library in a different namespace. The namespace is
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* specified in library_namespace.
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*/
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ANDROID_DLEXT_USE_NAMESPACE = 0x200,
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/* Mask of valid bits */
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ANDROID_DLEXT_VALID_FLAG_BITS = ANDROID_DLEXT_RESERVED_ADDRESS |
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ANDROID_DLEXT_RESERVED_ADDRESS_HINT |
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ANDROID_DLEXT_WRITE_RELRO |
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ANDROID_DLEXT_USE_RELRO |
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ANDROID_DLEXT_USE_LIBRARY_FD |
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ANDROID_DLEXT_USE_LIBRARY_FD_OFFSET |
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ANDROID_DLEXT_FORCE_LOAD |
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ANDROID_DLEXT_FORCE_FIXED_VADDR |
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ANDROID_DLEXT_LOAD_AT_FIXED_ADDRESS |
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ANDROID_DLEXT_USE_NAMESPACE,
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};
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struct android_namespace_t;
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typedef struct {
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uint64_t flags;
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void* reserved_addr;
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size_t reserved_size;
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int relro_fd;
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int library_fd;
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off64_t library_fd_offset;
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struct android_namespace_t* library_namespace;
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} android_dlextinfo;
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extern void* android_dlopen_ext(const char* filename, int flag, const android_dlextinfo* extinfo);
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/*
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* Initializes public and anonymous namespaces. The public_ns_sonames is the list of sonames
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* to be included into public namespace separated by colon. Example: "libc.so:libm.so:libdl.so".
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* The libraries in this list should be loaded prior to this call.
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*
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* The anon_ns_library_path is the search path for anonymous namespace. The anonymous namespace
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* is used in the case when linker cannot identify the caller of dlopen/dlsym. This happens
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* for the code not loaded by dynamic linker; for example calls from the mono-compiled code.
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*/
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extern bool android_init_namespaces(const char* public_ns_sonames,
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const char* anon_ns_library_path);
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enum {
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/* A regular namespace is the namespace with a custom search path that does
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* not impose any restrictions on the location of native libraries.
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*/
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ANDROID_NAMESPACE_TYPE_REGULAR = 0,
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/* An isolated namespace requires all the libraries to be on the search path
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* or under permitted_when_isolated_path. The search path is the union of
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* ld_library_path and default_library_path.
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*/
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ANDROID_NAMESPACE_TYPE_ISOLATED = 1,
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/* The shared namespace clones the list of libraries of the caller namespace upon creation
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* which means that they are shared between namespaces - the caller namespace and the new one
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* will use the same copy of a library if it was loaded prior to android_create_namespace call.
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*
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* Note that libraries loaded after the namespace is created will not be shared.
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*
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* Shared namespaces can be isolated or regular. Note that they do not inherit the search path nor
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* permitted_path from the caller's namespace.
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*/
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ANDROID_NAMESPACE_TYPE_SHARED = 2,
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ANDROID_NAMESPACE_TYPE_SHARED_ISOLATED = ANDROID_NAMESPACE_TYPE_SHARED |
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ANDROID_NAMESPACE_TYPE_ISOLATED,
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};
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/*
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* Creates new linker namespace.
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* ld_library_path and default_library_path represent the search path
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* for the libraries in the namespace.
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*
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* The libraries in the namespace are searched by folowing order:
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* 1. ld_library_path (Think of this as namespace-local LD_LIBRARY_PATH)
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* 2. In directories specified by DT_RUNPATH of the "needed by" binary.
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* 3. deault_library_path (This of this as namespace-local default library path)
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*
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* When type is ANDROID_NAMESPACE_TYPE_ISOLATED the resulting namespace requires all of
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* the libraries to be on the search path or under the permitted_when_isolated_path;
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* the search_path is ld_library_path:default_library_path. Note that the
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* permitted_when_isolated_path path is not part of the search_path and
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* does not affect the search order. It is a way to allow loading libraries from specific
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* locations when using absolute path.
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* If a library or any of its dependencies are outside of the permitted_when_isolated_path
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* and search_path, and it is not part of the public namespace dlopen will fail.
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*/
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extern struct android_namespace_t* android_create_namespace(const char* name,
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const char* ld_library_path,
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const char* default_library_path,
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uint64_t type,
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const char* permitted_when_isolated_path);
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__END_DECLS
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#endif /* __ANDROID_DLEXT_H__ */
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