183ad9df53
Add flags and a file descriptor to android_dlopen_ext() to allow writing the RELRO section of the loaded library to a file after relocation processing, and to allow mapping identical pages from the file over the top of relocated memory in another process. Explicitly comparing the pages is required in case a page contains a reference to a symbol defined in another library loaded at a random base address. Bug: 13005501 Change-Id: Ibb5b2d384edfaa5acf3e97a5f8b6115c10497a1e
71 lines
2.4 KiB
C
71 lines
2.4 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 <stddef.h>
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#include <sys/cdefs.h>
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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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/* 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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};
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typedef struct {
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int 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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} android_dlextinfo;
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extern void* android_dlopen_ext(const char* filename, int flag, const android_dlextinfo* extinfo);
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__END_DECLS
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#endif /* __ANDROID_DLEXT_H__ */
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