/*      $NetBSD: __longjmp14.c,v 1.7 2025/04/13 23:45:10 riastradh Exp $        */

/*-
 * Copyright (c) 2003 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Christian Limpach.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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 "namespace.h"
#include <sys/types.h>
#include <ucontext.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>

#define __LIBC12_SOURCE__
#include <setjmp.h>
#include <compat/include/setjmp.h>

#include <stdio.h>
#include <unistd.h>

ssize_t _sys_write(int, void *, size_t);

void
__longjmp14(jmp_buf env, int val)
{
        ucontext_t uc;
        struct sigcontext *sc = (void *)env;
        __register_t *regs = (void *)(sc + 1);
        register __register_t dp __asm("r27");

        /* Ensure non-zero SP */
        if (sc->sc_sp == 0)
                goto err;

        /* Make return value non-zero */
        if (val == 0)
                val = 1;

        /* Copy callee-saved regs */
        regs -= 3;
        uc.uc_mcontext.__gregs[3] = regs[3];
        uc.uc_mcontext.__gregs[4] = regs[4];
        uc.uc_mcontext.__gregs[5] = regs[5];
        uc.uc_mcontext.__gregs[6] = regs[6];
        uc.uc_mcontext.__gregs[7] = regs[7];
        uc.uc_mcontext.__gregs[8] = regs[8];
        uc.uc_mcontext.__gregs[9] = regs[9];
        uc.uc_mcontext.__gregs[10] = regs[10];
        uc.uc_mcontext.__gregs[11] = regs[11];
        uc.uc_mcontext.__gregs[12] = regs[12];
        uc.uc_mcontext.__gregs[13] = regs[13];
        uc.uc_mcontext.__gregs[14] = regs[14];
        uc.uc_mcontext.__gregs[15] = regs[15];
        uc.uc_mcontext.__gregs[16] = regs[16];
        uc.uc_mcontext.__gregs[17] = regs[17];
        uc.uc_mcontext.__gregs[18] = regs[18];

        /* Preserve the current value of DP */
        /* LINTED dp is r27, so is "initialized" */
        uc.uc_mcontext.__gregs[27] = dp;

        /* Set the desired return value. */
        uc.uc_mcontext.__gregs[_REG_RET0] = val;

        /*
         * Set _UC_CPU (restore CPU registers) and _UC_SIGMASK (restore
         * the signal mask) unconditionally.
         *
         * In the distant past of SA-based libpthread with sigprocmask
         * interception, we called sigprocmask here instead of using
         * _UC_SIGMASK -- but that restored the signal mask before the
         * stack pointer (PR lib/57946: longjmp fails to restore stack
         * first before restoring signal mask on most architectures),
         * which breaks sigaltstack, and SA-based libpthread is long
         * gone.  So we use _UC_SIGMASK.
         *
         * Set _UC_{SET,CLR}STACK according to SS_ONSTACK.
         */
        uc.uc_flags = _UC_CPU | _UC_SIGMASK;
        uc.uc_flags |= (sc->sc_onstack ? _UC_SETSTACK : _UC_CLRSTACK);

        /* Clear uc_link */
        uc.uc_link = 0;

        /* Copy signal mask */
        uc.uc_sigmask = sc->sc_mask;

        /* Copy special regs */
        uc.uc_mcontext.__gregs[_REG_PSW] = sc->sc_ps;
        uc.uc_mcontext.__gregs[_REG_SP] = sc->sc_sp;
        uc.uc_mcontext.__gregs[_REG_PCSQH] = sc->sc_pcsqh;
        uc.uc_mcontext.__gregs[_REG_PCOQH] = sc->sc_pcoqh;
        uc.uc_mcontext.__gregs[_REG_PCSQT] = sc->sc_pcsqt;
        uc.uc_mcontext.__gregs[_REG_PCOQT] = sc->sc_pcoqt;

        setcontext(&uc);
 err:
        longjmperror();
        abort();
        /* NOTREACHED */
}