freebsd-dev/lib/libc/i386/gen/signalcontext.c

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/*-
* Copyright (c) 2002 Jonathan Mini <mini@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. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 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/ucontext.h>
#include <machine/psl.h>
#include <machine/sigframe.h>
#include <signal.h>
#include <strings.h>
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__weak_reference(__signalcontext, signalcontext);
extern void _ctx_start(ucontext_t *, int argc, ...);
int
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__signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func)
{
register_t *p;
struct sigframe *sfp;
/*-
* Set up stack.
* (n = sizeof(int))
* 2n+sizeof(struct sigframe) ucp
* 2n struct sigframe
* 1n &func
* 0n &_ctx_start
*/
p = (register_t *)(void *)(intptr_t)ucp->uc_mcontext.mc_esp;
*--p = (register_t)(intptr_t)ucp;
p = (register_t *)((u_register_t)p & ~0xF); /* Align to 16 bytes. */
p = (register_t *)((u_register_t)p - sizeof(struct sigframe));
sfp = (struct sigframe *)p;
bzero(sfp, sizeof(struct sigframe));
sfp->sf_signum = sig;
sfp->sf_siginfo = (register_t)(intptr_t)&sfp->sf_si;
sfp->sf_ucontext = (register_t)(intptr_t)&sfp->sf_uc;
sfp->sf_ahu.sf_action = (__siginfohandler_t *)func;
bcopy(ucp, &sfp->sf_uc, sizeof(ucontext_t));
sfp->sf_si.si_signo = sig;
*--p = (register_t)(intptr_t)func;
/*
* Set up ucontext_t.
*/
ucp->uc_mcontext.mc_esi = ucp->uc_mcontext.mc_esp - sizeof(int);
ucp->uc_mcontext.mc_esp = (register_t)(intptr_t)p;
ucp->uc_mcontext.mc_eip = (register_t)(intptr_t)_ctx_start;
ucp->uc_mcontext.mc_eflags &= ~PSL_T;
ucp->uc_link = &sfp->sf_uc;
sigdelset(&ucp->uc_sigmask, sig);
return (0);
}