freebsd-dev/lib/libc/gen/swapcontext.c
Daniel Eischen b66b8326e5 Add getcontext, setcontext, makecontext, and swapcontext. These
functions are defined in SUSv2 and the latest POSIX spec.

Thanks to Bernd Walter <ticso@cicely8.cicely.de> for helping debug my
alpha assembly.

Approved by:	-arch
2002-01-10 02:40:59 +00:00

55 lines
1.8 KiB
C

/*
* Copyright (c) 2001 Daniel M. Eischen <deischen@freebsd.org>
* All rights reserved.
*
* 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 <errno.h>
#include <signal.h>
#include <ucontext.h>
__weak_reference(__swapcontext, swapcontext);
int
__swapcontext(ucontext_t *oucp, const ucontext_t *ucp)
{
volatile int swapped;
int ret;
if (oucp == NULL || ucp == NULL) {
errno = EINVAL;
ret = -1;
}
else {
swapped = 0;
if ((ret = getcontext(oucp) == 0) && (swapped == 0)) {
swapped = 1;
ret = setcontext(ucp);
}
}
return (ret);
}