glibc/io/lockf64.c
Paul Eggert 581c785bf3 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 11:40:24 -08:00

63 lines
2.0 KiB
C

/* Copyright (C) 1994-2022 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/>. */
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
/* lockf is a simplified interface to fcntl's locking facilities. */
int
__lockf64 (int fd, int cmd, off64_t len64)
{
/* lockf is always relative to the current file position. */
struct flock64 fl64 = {
.l_type = F_WRLCK,
.l_whence = SEEK_CUR,
.l_len = len64,
};
/* 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. */
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. */
fl64.l_type = F_RDLCK;
if (__fcntl (fd, F_GETLK64, &fl64) < 0)
return -1;
if (fl64.l_type == F_UNLCK || fl64.l_pid == __getpid ())
return 0;
__set_errno (EACCES);
return -1;
case F_ULOCK:
fl64.l_type = F_UNLCK;
return __fcntl64 (fd, F_SETLK64, &fl64);
case F_LOCK:
return __fcntl64 (fd, F_SETLKW64, &fl64);
case F_TLOCK:
return __fcntl64 (fd, F_SETLK64, &fl64);
}
__set_errno (EINVAL);
return -1;
}
weak_alias (__lockf64, lockf64)
#ifdef __OFF_T_MATCHES_OFF64_T
weak_alias (lockf64, lockf)
#endif