port/fp/sigfpe.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T
 * All Rights Reserved
 *
 * Portions of this source code were derived from Berkeley
 * 4.3 BSD under license from the regents of the University of
 * California.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/* Swap handler for SIGFPE codes.    */

#include "lint.h"
#include <mtlib.h>
#include <errno.h>
#include <signal.h>
#include <floatingpoint.h>
#include <sys/types.h>
#include <sys/ucontext.h>
#include <sys/siginfo.h>
#include <thread.h>
#include <synch.h>
#include <stdlib.h>

#ifndef FPE_INTDIV
#define FPE_INTDIV  1 /* integer divide by zero */
#endif
#ifndef FPE_INTOVF
#define FPE_INTOVF  2 /* integer overflow */
#endif
#ifndef FPE_FLTDIV
#define FPE_FLTDIV  3 /* [floating divide by zero] */
#endif
#ifndef FPE_FLTOVF
#define FPE_FLTOVF  4 /* [floating overflow] */
#endif
#ifndef FPE_FLTUND
#define FPE_FLTUND  5 /* [floating underflow] */
#endif
#ifndef FPE_FLTRES
#define FPE_FLTRES  6 /* [floating inexact result] */
#endif
#ifndef FPE_FLTINV
#define FPE_FLTINV  7 /* [floating invalid operation] */
#endif

#if defined(__i386) || defined(__amd64)

#ifndef FPE_FLTSUB
#define FPE_FLTSUB  8 /* subscript out of range */
#endif
#ifndef FPE_FLTDEN
#define FPE_FLTDEN  9 /* x86-specific: denormal operand */
#endif

#define N_SIGFPE_CODE   10

#else

#define N_SIGFPE_CODE   8

#endif /* __i386 */

/* Array of SIGFPE codes. */

static const sigfpe_code_type sigfpe_codes[N_SIGFPE_CODE] = {
    FPE_INTDIV,
    FPE_INTOVF,
    FPE_FLTDIV,
    FPE_FLTOVF,
    FPE_FLTUND,
    FPE_FLTRES,
    FPE_FLTINV,
#if defined(__i386) || defined(__amd64)
    FPE_FLTSUB,
    FPE_FLTDEN,
#endif
    0
};

/* Array of handlers. */

static mutex_t sigfpe_lock = DEFAULTMUTEX;

sigfpe_handler_type ieee_handlers[N_IEEE_EXCEPTION];
static sigfpe_handler_type sigfpe_handlers[N_SIGFPE_CODE];

static  int _sigfpe_master_enabled;
/* Originally zero, set to 1 by _enable_sigfpe_master. */

#ifndef BADSIG
#define BADSIG      (void (*)(void))-1
#endif

static void
_sigfpe_master(int sig, siginfo_t *siginfo, void *arg)
{
    ucontext_t  *ucontext = arg;
    int     i;
    int     code;
    enum fp_exception_type exception;

    lmutex_lock(&sigfpe_lock);
    code = siginfo->si_code;
    for (i = 0; (i < N_SIGFPE_CODE) && (code != sigfpe_codes[i]); i++)
        continue;
    /* Find index of handler. */
    if (i >= N_SIGFPE_CODE)
        i = N_SIGFPE_CODE - 1;
    switch ((intptr_t)sigfpe_handlers[i]) {
    case ((intptr_t)(SIGFPE_DEFAULT)):
        switch (code) {
        case FPE_FLTINV:
            exception = fp_invalid;
            goto ieee;
        case FPE_FLTRES:
            exception = fp_inexact;
            goto ieee;
        case FPE_FLTDIV:
            exception = fp_division;
            goto ieee;
        case FPE_FLTUND:
            exception = fp_underflow;
            goto ieee;
        case FPE_FLTOVF:
            exception = fp_overflow;
            goto ieee;
        default:    /* The common default treatment is to abort. */
            break;
        }
    case ((intptr_t)(SIGFPE_ABORT)):
        abort();
        break;
    case ((intptr_t)(SIGFPE_IGNORE)):
        lmutex_unlock(&sigfpe_lock);
        return;
    default:    /* User-defined not SIGFPE_DEFAULT or SIGFPE_ABORT. */
        (sigfpe_handlers[i])(sig, siginfo, ucontext);
        lmutex_unlock(&sigfpe_lock);
        return;
    }
ieee:
    switch ((intptr_t)ieee_handlers[(int)exception]) {
    case ((intptr_t)(SIGFPE_DEFAULT)): /* Error condition but ignore it. */
    case ((intptr_t)(SIGFPE_IGNORE)): /* Error condition but ignore it. */
        lmutex_unlock(&sigfpe_lock);
        return;
    case ((intptr_t)(SIGFPE_ABORT)):
        abort();
    default:
        (ieee_handlers[(int)exception])(sig, siginfo, ucontext);
        lmutex_unlock(&sigfpe_lock);
        return;
    }
}

static int
_enable_sigfpe_master(void)
{
    /* Enable the sigfpe master handler always. */
    struct sigaction newsigact, oldsigact;

    newsigact.sa_sigaction = _sigfpe_master;
    (void) sigemptyset(&newsigact.sa_mask);
    newsigact.sa_flags = SA_SIGINFO;    /* enhanced handler */
    _sigfpe_master_enabled = 1;
    return (sigaction(SIGFPE, &newsigact, &oldsigact));
}

static int
_test_sigfpe_master(void)
{
    /*
     * Enable the sigfpe master handler if it's never been enabled
     * before.
     */

    if (_sigfpe_master_enabled == 0)
        return (_enable_sigfpe_master());
    else
        return (_sigfpe_master_enabled);
}

sigfpe_handler_type
sigfpe(sigfpe_code_type code, sigfpe_handler_type hdl)
{
    sigfpe_handler_type oldhdl;
    int     i;

    lmutex_lock(&sigfpe_lock);
    (void) _test_sigfpe_master();
    for (i = 0; (i < N_SIGFPE_CODE) && (code != sigfpe_codes[i]); i++)
        continue;
    /* Find index of handler. */
    if (i >= N_SIGFPE_CODE) {
        errno = EINVAL;
        lmutex_unlock(&sigfpe_lock);
        /* Not 0 or SIGFPE code */
        return ((sigfpe_handler_type)BADSIG);
    }
    oldhdl = sigfpe_handlers[i];
    sigfpe_handlers[i] = hdl;
    lmutex_unlock(&sigfpe_lock);
    return (oldhdl);
}