glibc/sysdeps/generic/lockf.c
Ulrich Drepper 7a1147946e Update.
2003-06-15  Ulrich Drepper  <drepper@redhat.com>

	Fix cancellation point handling wrt exception based cleanup.
	* io/Makefile: Compile fcntl.c, poll.c, and lockf.c with exceptions.
	* misc/Makefile: Compile pselect.c, readv.c, writev.c, and usleep.c
	with exceptions.
	* posix/Makefile: Compile pread.c, pread64.c, pwrite.c, pwrite64.c,
	sleep.c, wait.c, waitid.c, and waitpid.c with exceptions.
	* rt/Makefile: Compile aio_suspend.c and clock_nanosleep.c with
	exceptions.
	* signal/Makefile: Compile sigpause.c, sigsuspend.c, sigtimedwait.c,
	sigwait.c, and sigwaitinfo.c with exceptions.
	* stdlib/Makefile: Compile system.c with exceptions.
	* sysvipc/Makefile: Compile msgrcv.c and msgsnd.c with exceptions.
	* termios/Makefile: Compile tcdrain.c with exceptions.
	* sysdeps/generic/lockf.c: Add comment explaining the cancellation
	situation.
	* sysdeps/generic/pselect.c: Likewise.
	* sysdeps/posix/sigpause.c: Likewise.
	* sysdeps/posix/system.c: Likewise.
	* sysdeps/posix/waitid.c: Likewise.
	* sysdeps/unix/sysv/linux/sleep.c: Likewise.
	* sysdeps/unix/sysv/linux/usleep.c: Likewise.
	* sysdeps/unix/sysv/linux/i386/sysdep.h: Major rewrite of
	INTERNAL_SYSCALL to not use push inside asm statement so that
	unwind info is correct around the syscall.
	* sysdeps/unix/clock_nanosleep.c: Add cancellation support.
	* sysdeps/unix/sysv/linux/clock_nanosleep.c: Likewise.
2003-06-15 21:22:26 +00:00

75 lines
2.1 KiB
C

/* Copyright (C) 1994,1996,1997,1998,2000,2003 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
/* lockf is a simplified interface to fcntl's locking facilities. */
int
lockf (int fd, int cmd, off_t len)
{
struct flock fl;
memset ((char *) &fl, '\0', sizeof (fl));
/* lockf is always relative to the current file position. */
fl.l_whence = SEEK_CUR;
fl.l_start = 0;
fl.l_len = len;
switch (cmd)
{
case F_TEST:
/* Test the lock: return 0 if FD is unlocked or locked by this process;
return -1, set errno to EACCES, if another process holds the lock. */
fl.l_type = F_RDLCK;
if (__fcntl (fd, F_GETLK, &fl) < 0)
return -1;
if (fl.l_type == F_UNLCK || fl.l_pid == __getpid ())
return 0;
__set_errno (EACCES);
return -1;
case F_ULOCK:
fl.l_type = F_UNLCK;
cmd = F_SETLK;
break;
case F_LOCK:
fl.l_type = F_WRLCK;
cmd = F_SETLKW;
break;
case F_TLOCK:
fl.l_type = F_WRLCK;
cmd = F_SETLK;
break;
default:
__set_errno (EINVAL);
return -1;
}
/* lockf() is a cancellation point but so is fcntl() if F_SETLKW is
used. Therefore we don't have to care about cancellation here,
the fcntl() function will take care of it. */
return __fcntl (fd, cmd, &fl);
}