109 lines
3.1 KiB
C
109 lines
3.1 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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*
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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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/*
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* System utilities.
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*/
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#ifndef LIBDEX_SYSUTIL_H_
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#define LIBDEX_SYSUTIL_H_
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#include <sys/types.h>
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/*
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* System page size. Normally you're expected to get this from
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* sysconf(_SC_PAGESIZE) or some system-specific define (usually PAGESIZE
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* or PAGE_SIZE). If we use a simple #define the compiler can generate
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* appropriate masks directly, so we define it here and verify it as the
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* VM is starting up.
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*
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* Must be a power of 2.
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*/
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#ifdef PAGE_SHIFT
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#define SYSTEM_PAGE_SIZE (1<<PAGE_SHIFT)
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#else
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#define SYSTEM_PAGE_SIZE 4096
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#endif
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/*
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* Use this to keep track of mapped segments.
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*/
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struct MemMapping {
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void* addr; /* start of data */
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size_t length; /* length of data */
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void* baseAddr; /* page-aligned base address */
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size_t baseLength; /* length of mapping */
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};
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/*
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* Copy a map.
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*/
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void sysCopyMap(MemMapping* dst, const MemMapping* src);
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/*
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* Map a file (from fd's current offset) into a shared, read-only memory
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* segment that can be made writable. (In some cases, such as when
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* mapping a file on a FAT filesystem, the result may be fully writable.)
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*
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* On success, "pMap" is filled in, and zero is returned.
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*/
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int sysMapFileInShmemWritableReadOnly(int fd, MemMapping* pMap);
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/*
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* Map part of a file into a shared, read-only memory segment.
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*
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* On success, "pMap" is filled in, and zero is returned.
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*/
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int sysMapFileSegmentInShmem(int fd, off_t start, size_t length,
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MemMapping* pMap);
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/*
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* Create a private anonymous mapping, useful for large allocations.
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*
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* On success, "pMap" is filled in, and zero is returned.
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*/
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int sysCreatePrivateMap(size_t length, MemMapping* pMap);
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/*
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* Change the access rights on one or more pages. If "wantReadWrite" is
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* zero, the pages will be made read-only; otherwise they will be read-write.
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*
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* Returns 0 on success.
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*/
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int sysChangeMapAccess(void* addr, size_t length, int wantReadWrite,
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MemMapping* pmap);
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/*
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* Release the pages associated with a shared memory segment.
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*
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* This does not free "pMap"; it just releases the memory.
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*/
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void sysReleaseShmem(MemMapping* pMap);
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/*
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* Write until all bytes have been written.
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*
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* Returns 0 on success, or an errno value on failure.
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*/
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int sysWriteFully(int fd, const void* buf, size_t count, const char* logMsg);
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/*
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* Copy the given number of bytes from one fd to another. Returns
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* 0 on success, -1 on failure.
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*/
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int sysCopyFileToFile(int outFd, int inFd, size_t count);
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#endif // LIBDEX_SYSUTIL_H_
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