freebsd-dev/lib/libc/sys/swapcontext.c
Conrad Meyer 1e72c52e23 libc: partially revert r326576
In r326576 ("use @@@ instead of @@ in __sym_default"), an earlier version of
the phabricator-discussed patch was inadvertently committed.  The commit
message claims that @@@ means that weak is not needed, but that was due to a
misunderstanding of the use of weak symbols in this context by the submitted
in the first draft of the patch; the description text was not updated to
match the discussion.  As discussed in phabricator, weak is needed for
symbol interposing because of the behavior of our rtld, and is widely used
elsewhere in libc.

This partial revert restores the approved version of the patch and permits
symbol interposing for openat.

Reported by:	Raymond Ramsden <rramsden AT isilon.com>
Reviewed by:	dim, emaste, kib (2017)
Discussed with:	kib (2020)
Differential Revision:	https://reviews.freebsd.org/D11653
2020-04-25 14:24:54 +00:00

54 lines
2.1 KiB
C

/*
* Copyright (c) 2001 Daniel M. Eischen <deischen@freebsd.org>
* Copyright (c) 2014 The FreeBSD Foundation.
* All rights reserved.
*
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Neither the name of the author nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/signal.h>
#include <sys/ucontext.h>
#include <errno.h>
#include <stddef.h>
#include "libc_private.h"
__weak_reference(__sys_swapcontext, __swapcontext);
__sym_compat(swapcontext, __impl_swapcontext, FBSD_1.0);
__weak_reference(swapcontext, __impl_swapcontext);
__sym_default(swapcontext, swapcontext, FBSD_1.2);
#pragma weak swapcontext
int
swapcontext(ucontext_t *oucp, const ucontext_t *ucp)
{
return (((int (*)(ucontext_t *, const ucontext_t *))
__libc_interposing[INTERPOS_swapcontext])(oucp, ucp));
}