From 522dc8552e844b12fa505404585f922b50cc2ea2 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Tue, 29 Feb 2000 08:02:20 +0000 Subject: Update. * io/lockf.c: Moved to... * sysdeps/generic/lockf.c: ...here. --- sysdeps/generic/lockf.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 sysdeps/generic/lockf.c (limited to 'sysdeps/generic/lockf.c') diff --git a/sysdeps/generic/lockf.c b/sysdeps/generic/lockf.c new file mode 100644 index 0000000000..6e8851bed7 --- /dev/null +++ b/sysdeps/generic/lockf.c @@ -0,0 +1,70 @@ +/* Copyright (C) 1994, 1996, 1997, 1998 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 Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include +#include +#include +#include +#include + +/* 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. */ + 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; + } + + return __fcntl (fd, cmd, &fl); +} -- cgit v1.2.3