xref: /titanic_50/usr/src/lib/libc/port/fp/sigfpe.c (revision c7158ae983f5a04c4a998f468ecefba6d23ba721)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  *
22  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  *
25  * Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T
26  * All Rights Reserved
27  *
28  * Portions of this source code were derived from Berkeley
29  * 4.3 BSD under license from the regents of the University of
30  * California.
31  */
32 
33 #pragma ident	"%Z%%M%	%I%	%E% SMI"
34 
35 /* Swap handler for SIGFPE codes.	 */
36 
37 #pragma weak sigfpe = _sigfpe
38 
39 #include "synonyms.h"
40 #include <mtlib.h>
41 #include <errno.h>
42 #include <signal.h>
43 #include <floatingpoint.h>
44 #include <sys/types.h>
45 #include <sys/ucontext.h>
46 #include <sys/siginfo.h>
47 #include <thread.h>
48 #include <synch.h>
49 #include <stdlib.h>
50 
51 #ifndef FPE_INTDIV
52 #define	FPE_INTDIV	1 /* integer divide by zero */
53 #endif
54 #ifndef FPE_INTOVF
55 #define	FPE_INTOVF	2 /* integer overflow */
56 #endif
57 #ifndef FPE_FLTDIV
58 #define	FPE_FLTDIV	3 /* [floating divide by zero] */
59 #endif
60 #ifndef FPE_FLTOVF
61 #define	FPE_FLTOVF	4 /* [floating overflow] */
62 #endif
63 #ifndef FPE_FLTUND
64 #define	FPE_FLTUND	5 /* [floating underflow] */
65 #endif
66 #ifndef FPE_FLTRES
67 #define	FPE_FLTRES	6 /* [floating inexact result] */
68 #endif
69 #ifndef FPE_FLTINV
70 #define	FPE_FLTINV	7 /* [floating invalid operation] */
71 #endif
72 
73 #if defined(__i386) || defined(__amd64)
74 
75 #ifndef	FPE_FLTSUB
76 #define	FPE_FLTSUB	8 /* subscript out of range */
77 #endif
78 #ifndef	FPE_FLTDEN
79 #define	FPE_FLTDEN	9 /* x86-specific: denormal operand */
80 #endif
81 
82 #define	N_SIGFPE_CODE	10
83 
84 #else
85 
86 #define	N_SIGFPE_CODE	8
87 
88 #endif /* __i386 */
89 
90 /* Array of SIGFPE codes. */
91 
92 static const sigfpe_code_type sigfpe_codes[N_SIGFPE_CODE] = {
93 	FPE_INTDIV,
94 	FPE_INTOVF,
95 	FPE_FLTDIV,
96 	FPE_FLTOVF,
97 	FPE_FLTUND,
98 	FPE_FLTRES,
99 	FPE_FLTINV,
100 #if defined(__i386) || defined(__amd64)
101 	FPE_FLTSUB,
102 	FPE_FLTDEN,
103 #endif
104 	0
105 };
106 
107 /* Array of handlers. */
108 
109 static mutex_t sigfpe_lock = DEFAULTMUTEX;
110 
111 sigfpe_handler_type ieee_handlers[N_IEEE_EXCEPTION];
112 static sigfpe_handler_type sigfpe_handlers[N_SIGFPE_CODE];
113 
114 static	int	_sigfpe_master_enabled;
115 /* Originally zero, set to 1 by _enable_sigfpe_master. */
116 
117 #ifndef BADSIG
118 #define	BADSIG		(void (*)(void))-1
119 #endif
120 
121 static void
122 _sigfpe_master(int sig, siginfo_t *siginfo, void *arg)
123 {
124 	ucontext_t	*ucontext = arg;
125 	int		i;
126 	int		code;
127 	enum fp_exception_type exception;
128 
129 	lmutex_lock(&sigfpe_lock);
130 	code = siginfo->si_code;
131 	for (i = 0; (i < N_SIGFPE_CODE) && (code != sigfpe_codes[i]); i++);
132 	/* Find index of handler. */
133 	if (i >= N_SIGFPE_CODE)
134 		i = N_SIGFPE_CODE - 1;
135 	switch ((intptr_t)sigfpe_handlers[i]) {
136 	case ((intptr_t)(SIGFPE_DEFAULT)):
137 		switch (code) {
138 		case FPE_FLTINV:
139 			exception = fp_invalid;
140 			goto ieee;
141 		case FPE_FLTRES:
142 			exception = fp_inexact;
143 			goto ieee;
144 		case FPE_FLTDIV:
145 			exception = fp_division;
146 			goto ieee;
147 		case FPE_FLTUND:
148 			exception = fp_underflow;
149 			goto ieee;
150 		case FPE_FLTOVF:
151 			exception = fp_overflow;
152 			goto ieee;
153 		default:	/* The common default treatment is to abort. */
154 			break;
155 		}
156 	case ((intptr_t)(SIGFPE_ABORT)):
157 		abort();
158 		break;
159 	case ((intptr_t)(SIGFPE_IGNORE)):
160 		lmutex_unlock(&sigfpe_lock);
161 		return;
162 	default:	/* User-defined not SIGFPE_DEFAULT or SIGFPE_ABORT. */
163 		(sigfpe_handlers[i])(sig, siginfo, ucontext);
164 		lmutex_unlock(&sigfpe_lock);
165 		return;
166 	}
167 ieee:
168 	switch ((intptr_t)ieee_handlers[(int)exception]) {
169 	case ((intptr_t)(SIGFPE_DEFAULT)): /* Error condition but ignore it. */
170 	case ((intptr_t)(SIGFPE_IGNORE)): /* Error condition but ignore it. */
171 		lmutex_unlock(&sigfpe_lock);
172 		return;
173 	case ((intptr_t)(SIGFPE_ABORT)):
174 		abort();
175 	default:
176 		(ieee_handlers[(int)exception])(sig, siginfo, ucontext);
177 		lmutex_unlock(&sigfpe_lock);
178 		return;
179 	}
180 }
181 
182 static int
183 _enable_sigfpe_master(void)
184 {
185 	/* Enable the sigfpe master handler always. */
186 	struct sigaction newsigact, oldsigact;
187 
188 	newsigact.sa_sigaction = _sigfpe_master;
189 	(void) sigemptyset(&newsigact.sa_mask);
190 	newsigact.sa_flags = SA_SIGINFO;	/* enhanced handler */
191 	_sigfpe_master_enabled = 1;
192 	return (sigaction(SIGFPE, &newsigact, &oldsigact));
193 }
194 
195 static int
196 _test_sigfpe_master(void)
197 {
198 	/*
199 	 * Enable the sigfpe master handler if it's never been enabled
200 	 * before.
201 	 */
202 
203 	if (_sigfpe_master_enabled == 0)
204 		return (_enable_sigfpe_master());
205 	else
206 		return (_sigfpe_master_enabled);
207 }
208 
209 sigfpe_handler_type
210 sigfpe(sigfpe_code_type code, sigfpe_handler_type hdl)
211 {
212 	sigfpe_handler_type oldhdl;
213 	int		i;
214 
215 	lmutex_lock(&sigfpe_lock);
216 	(void) _test_sigfpe_master();
217 	for (i = 0; (i < N_SIGFPE_CODE) && (code != sigfpe_codes[i]); i++);
218 	/* Find index of handler. */
219 	if (i >= N_SIGFPE_CODE) {
220 		errno = EINVAL;
221 		lmutex_unlock(&sigfpe_lock);
222 		/* Not 0 or SIGFPE code */
223 		return ((sigfpe_handler_type)BADSIG);
224 	}
225 	oldhdl = sigfpe_handlers[i];
226 	sigfpe_handlers[i] = hdl;
227 	lmutex_unlock(&sigfpe_lock);
228 	return (oldhdl);
229 }
230