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/*
* Copyright (c) 2003 Marcel Moolenaar
* 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 ``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 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/types.h>
#include <sys/ucontext.h>
#include <signal.h>
#include <stdlib.h>
#include <strings.h>
typedef void (*handler_t)(uint64_t, uint64_t, uint64_t);
/* Prototypes */
static void sigctx_wrapper(ucontext_t *ucp, handler_t func, uint64_t *args);
__weak_reference(__signalcontext, signalcontext);
int
__signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func)
{
uint64_t *args;
siginfo_t *sig_si;
ucontext_t *sig_uc;
uint64_t sp;
/* Bail out if we don't have a valid ucontext pointer. */
if (ucp == NULL)
abort();
/*
* Build a signal frame and copy the arguments of signal handler
* 'func' onto the stack and do the funky stack alignment.
* This means that we need an 8-byte-odd alignment since the ABI expects
* the return address to be pushed, thus breaking the 16 byte alignment.
*/
sp = (ucp->uc_mcontext.mc_rsp - 128 - sizeof(ucontext_t)) & ~15UL;
sig_uc = (ucontext_t *)sp;
bcopy(ucp, sig_uc, sizeof(*sig_uc));
sp = (sp - sizeof(siginfo_t)) & ~15UL;
sig_si = (siginfo_t *)sp;
bzero(sig_si, sizeof(*sig_si));
sig_si->si_signo = sig;
sp -= 3 * sizeof(uint64_t);
args = (uint64_t *)sp;
args[0] = sig;
args[1] = (intptr_t)sig_si;
args[2] = (intptr_t)sig_uc;
sp -= 16;
/*
* Setup the ucontext of the signal handler.
*/
bzero(&ucp->uc_mcontext, sizeof(ucp->uc_mcontext));
ucp->uc_mcontext.mc_fpformat = _MC_FPFMT_NODEV;
ucp->uc_mcontext.mc_ownedfp = _MC_FPOWNED_NONE;
ucp->uc_link = sig_uc;
sigdelset(&ucp->uc_sigmask, sig);
ucp->uc_mcontext.mc_len = sizeof(mcontext_t);
ucp->uc_mcontext.mc_rdi = (register_t)ucp;
ucp->uc_mcontext.mc_rsi = (register_t)func;
ucp->uc_mcontext.mc_rdx = (register_t)args;
ucp->uc_mcontext.mc_rbp = (register_t)sp;
ucp->uc_mcontext.mc_rbx = (register_t)sp;
ucp->uc_mcontext.mc_rsp = (register_t)sp;
ucp->uc_mcontext.mc_rip = (register_t)sigctx_wrapper;
return (0);
}
static void
sigctx_wrapper(ucontext_t *ucp, handler_t func, uint64_t *args)
{
(*func)(args[0], args[1], args[2]);
if (ucp->uc_link == NULL)
exit(0);
setcontext((const ucontext_t *)ucp->uc_link);
/* should never get here */
abort();
/* NOTREACHED */
}
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