mirror of
https://sourceware.org/git/glibc.git
synced 2025-10-30 10:45:40 +03:00
57 lines
1.7 KiB
C
57 lines
1.7 KiB
C
/* Copyright (C) 1992-2024 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, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
/* This file implements the `flock' function in terms of the POSIX.1 `fcntl'
|
|
locking mechanism. In 4BSD, these are two incompatible locking mechanisms,
|
|
perhaps with different semantics? */
|
|
|
|
#include <errno.h>
|
|
#include <unistd.h>
|
|
#include <fcntl.h>
|
|
#include <sys/file.h>
|
|
|
|
/* Apply or remove an advisory lock, according to OPERATION,
|
|
on the file FD refers to. */
|
|
int
|
|
__flock (int fd, int operation)
|
|
{
|
|
struct flock lbuf;
|
|
|
|
switch (operation & ~LOCK_NB)
|
|
{
|
|
case LOCK_SH:
|
|
lbuf.l_type = F_RDLCK;
|
|
break;
|
|
case LOCK_EX:
|
|
lbuf.l_type = F_WRLCK;
|
|
break;
|
|
case LOCK_UN:
|
|
lbuf.l_type = F_UNLCK;
|
|
break;
|
|
default:
|
|
__set_errno (EINVAL);
|
|
return -1;
|
|
}
|
|
|
|
lbuf.l_whence = SEEK_SET;
|
|
lbuf.l_start = lbuf.l_len = 0L; /* Lock the whole file. */
|
|
|
|
return __fcntl (fd, (operation & LOCK_NB) ? F_SETLK : F_SETLKW, &lbuf);
|
|
}
|
|
|
|
weak_alias (__flock, flock)
|