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69 lines
1.9 KiB
C
69 lines
1.9 KiB
C
/* Copyright (C) 1994-2015 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sys/types.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <string.h>
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#include <sysdep.h>
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/* lockf is a simplified interface to fcntl's locking facilities. */
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int
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lockf64 (int fd, int cmd, off64_t len64)
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{
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struct flock64 fl64;
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int cmd64;
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memset ((char *) &fl64, '\0', sizeof (fl64));
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fl64.l_whence = SEEK_CUR;
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fl64.l_start = 0;
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fl64.l_len = len64;
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switch (cmd)
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{
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case F_TEST:
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/* Test the lock: return 0 if FD is unlocked or locked by this process;
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return -1, set errno to EACCES, if another process holds the lock. */
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fl64.l_type = F_RDLCK;
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if (INLINE_SYSCALL (fcntl64, 3, fd, F_GETLK64, &fl64) < 0)
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return -1;
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if (fl64.l_type == F_UNLCK || fl64.l_pid == __getpid ())
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return 0;
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__set_errno (EACCES);
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return -1;
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case F_ULOCK:
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fl64.l_type = F_UNLCK;
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cmd64 = F_SETLK64;
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break;
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case F_LOCK:
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fl64.l_type = F_WRLCK;
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cmd64 = F_SETLKW64;
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break;
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case F_TLOCK:
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fl64.l_type = F_WRLCK;
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cmd64 = F_SETLK64;
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break;
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default:
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__set_errno (EINVAL);
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return -1;
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}
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return INLINE_SYSCALL (fcntl64, 3, fd, cmd64, &fl64);
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}
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