e2a39e2efa
* flock.cc (flock): Use struct __flock64. Call fcntl_worker. Use Cygwin errno functions instead of accessing errno directly. * winsup.h: Declare fcntl_worker.
90 lines
1.7 KiB
C++
90 lines
1.7 KiB
C++
/* One of many ways to emulate flock() on top of real (good) POSIX locks.
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*
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* This flock() emulation is based upon source taken from the Red Hat
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* implementation used in their imap-2002d SRPM.
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*
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* $RH: flock.c,v 1.2 2000/08/23 17:07:00 nalin Exp $
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*/
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/* flock.c
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Copyright 2003 Red Hat, Inc.
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This file is part of Cygwin.
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This software is a copyrighted work licensed under the terms of the
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Cygwin license. Please consult the file "CYGWIN_LICENSE" for
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details. */
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#include "winsup.h"
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#include "cygerrno.h"
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#include <sys/file.h>
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#include <fcntl.h>
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#include <unistd.h>
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int
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flock (int fd, int operation)
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{
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int i, cmd;
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struct __flock64 l = { 0, 0, 0, 0, 0 };
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if (operation & LOCK_NB)
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{
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cmd = F_SETLK;
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}
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else
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{
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cmd = F_SETLKW;
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}
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l.l_whence = SEEK_SET;
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switch (operation & (~LOCK_NB))
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{
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case LOCK_EX:
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l.l_type = F_WRLCK;
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i = fcntl_worker (fd, cmd, &l);
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if (i == -1)
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{
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if ((get_errno () == EAGAIN) || (get_errno () == EACCES))
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{
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set_errno (EWOULDBLOCK);
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}
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}
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break;
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case LOCK_SH:
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l.l_type = F_RDLCK;
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i = fcntl_worker (fd, cmd, &l);
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if (i == -1)
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{
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if ((get_errno () == EAGAIN) || (get_errno () == EACCES))
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{
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set_errno (EWOULDBLOCK);
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}
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}
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break;
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case LOCK_UN:
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l.l_type = F_UNLCK;
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i = fcntl_worker (fd, cmd, &l);
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if (i == -1)
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{
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if ((get_errno () == EAGAIN) || (get_errno () == EACCES))
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{
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set_errno (EWOULDBLOCK);
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}
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}
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break;
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default:
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i = -1;
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set_errno (EINVAL);
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break;
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}
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return i;
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}
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#ifdef FLOCK_EMULATE_IS_MAIN
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int
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main (int argc, char **argv)
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{
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int fd = open (argv[1], O_WRONLY);
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flock (fd, LOCK_EX);
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return 0;
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}
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#endif
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