78 lines
1.4 KiB
C
Executable File
78 lines
1.4 KiB
C
Executable File
/* Copyright (c) 1988 AT&T */
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/* All Rights Reserved */
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/* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T */
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/* The copyright notice above does not evidence any */
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/* actual or intended publication of such source code. */
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#ident "@(#)lockf.c 1.8 93/08/16 SMI" /* SVr4.0 1.16 */
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#ifdef __STDC__
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#pragma weak lockf = _lockf
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#endif
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#include "synonyms.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <unistd.h>
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lockf(fildes, function, size)
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long size;
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int fildes, function;
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{
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struct flock l;
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int rv;
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l.l_whence = 1;
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if (size < 0) {
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l.l_start = size;
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l.l_len = -size;
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} else {
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l.l_start = 0L;
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l.l_len = size;
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}
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switch (function) {
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case F_ULOCK:
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l.l_type = F_UNLCK;
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rv = fcntl(fildes, F_SETLK, &l);
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break;
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case F_LOCK:
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l.l_type = F_WRLCK;
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rv = fcntl(fildes, F_SETLKW, &l);
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break;
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case F_TLOCK:
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l.l_type = F_WRLCK;
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rv = fcntl(fildes, F_SETLK, &l);
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break;
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case F_TEST:
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l.l_type = F_WRLCK;
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rv = fcntl(fildes, F_GETLK, &l);
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if (rv != -1) {
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if (l.l_type == F_UNLCK)
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return (0);
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else {
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errno = EAGAIN;
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return (-1);
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}
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}
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break;
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default:
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errno = EINVAL;
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return (-1);
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}
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if (rv < 0) {
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switch(errno) {
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case EMFILE:
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case ENOSPC:
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case ENOLCK:
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/* A deadlock error is given if we run out of resources,
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* in compliance with /usr/group standards.
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*/
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errno = EDEADLK;
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break;
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default:
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break;
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}
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}
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return (rv);
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}
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