73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
/*
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* Copyright (C) 2016 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <unistd.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <string.h>
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int lockf64(int fd, int cmd, off64_t length) {
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// Translate POSIX lockf into fcntl.
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struct flock64 fl;
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memset(&fl, 0, sizeof(fl));
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fl.l_whence = SEEK_CUR;
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fl.l_start = 0;
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fl.l_len = length;
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if (cmd == F_ULOCK) {
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fl.l_type = F_UNLCK;
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cmd = F_SETLK64;
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return fcntl(fd, F_SETLK64, &fl);
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}
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if (cmd == F_LOCK) {
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fl.l_type = F_WRLCK;
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return fcntl(fd, F_SETLKW64, &fl);
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}
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if (cmd == F_TLOCK) {
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fl.l_type = F_WRLCK;
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return fcntl(fd, F_SETLK64, &fl);
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}
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if (cmd == F_TEST) {
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fl.l_type = F_RDLCK;
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if (fcntl(fd, F_GETLK64, &fl) == -1) return -1;
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if (fl.l_type == F_UNLCK || fl.l_pid == getpid()) return 0;
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errno = EACCES;
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return -1;
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}
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errno = EINVAL;
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return -1;
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}
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int lockf(int fd, int cmd, off_t length) {
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return lockf64(fd, cmd, length);
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}
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