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comparison src/os/aix/vm/jsig.c @ 14415:666e6ce3976c

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8023038: PPC64 (part 15): Platform files for AIX/PPC64 support Reviewed-by: kvn
author simonis
date Fri, 06 Sep 2013 20:16:09 +0200
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14414:b83f7d608548 14415:666e6ce3976c
1 /*
2 * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
3 * Copyright 2012, 2013 SAP AG. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 /* CopyrightVersion 1.2 */
27
28 /* This is a special library that should be loaded before libc &
29 * libthread to interpose the signal handler installation functions:
30 * sigaction(), signal(), sigset().
31 * Used for signal-chaining. See RFE 4381843.
32 */
33
34 #include <signal.h>
35 #include <dlfcn.h>
36 #include <pthread.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39
40 #define bool int
41 #define true 1
42 #define false 0
43
44 // Highest so far on AIX 5.2 is SIGSAK (63)
45 #define MAXSIGNUM 63
46 #define MASK(sig) ((unsigned int)1 << sig)
47
48 static struct sigaction sact[MAXSIGNUM]; /* saved signal handlers */
49 static unsigned int jvmsigs = 0; /* signals used by jvm */
50
51 /* used to synchronize the installation of signal handlers */
52 static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
53 static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
54 static pthread_t tid = 0;
55
56 typedef void (*sa_handler_t)(int);
57 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
58 // signal_t is already defined on AIX
59 typedef sa_handler_t (*signal_like_function_t)(int, sa_handler_t);
60 typedef int (*sigaction_t)(int, const struct sigaction *, struct sigaction *);
61
62 static signal_like_function_t os_signal = 0; /* os's version of signal()/sigset() */
63 static sigaction_t os_sigaction = 0; /* os's version of sigaction() */
64
65 static bool jvm_signal_installing = false;
66 static bool jvm_signal_installed = false;
67
68 static void signal_lock() {
69 pthread_mutex_lock(&mutex);
70 /* When the jvm is installing its set of signal handlers, threads
71 * other than the jvm thread should wait */
72 if (jvm_signal_installing) {
73 if (tid != pthread_self()) {
74 pthread_cond_wait(&cond, &mutex);
75 }
76 }
77 }
78
79 static void signal_unlock() {
80 pthread_mutex_unlock(&mutex);
81 }
82
83 static sa_handler_t call_os_signal(int sig, sa_handler_t disp,
84 bool is_sigset) {
85 if (os_signal == NULL) {
86 if (!is_sigset) {
87 // Aix: call functions directly instead of dlsym'ing them
88 os_signal = signal;
89 } else {
90 // Aix: call functions directly instead of dlsym'ing them
91 os_signal = sigset;
92 }
93 if (os_signal == NULL) {
94 printf("%s\n", dlerror());
95 exit(0);
96 }
97 }
98 return (*os_signal)(sig, disp);
99 }
100
101 static void save_signal_handler(int sig, sa_handler_t disp) {
102 sigset_t set;
103 sact[sig].sa_handler = disp;
104 sigemptyset(&set);
105 sact[sig].sa_mask = set;
106 sact[sig].sa_flags = 0;
107 }
108
109 static sa_handler_t set_signal(int sig, sa_handler_t disp, bool is_sigset) {
110 sa_handler_t oldhandler;
111 bool sigused;
112
113 signal_lock();
114
115 sigused = (MASK(sig) & jvmsigs) != 0;
116 if (jvm_signal_installed && sigused) {
117 /* jvm has installed its signal handler for this signal. */
118 /* Save the handler. Don't really install it. */
119 oldhandler = sact[sig].sa_handler;
120 save_signal_handler(sig, disp);
121
122 signal_unlock();
123 return oldhandler;
124 } else if (jvm_signal_installing) {
125 /* jvm is installing its signal handlers. Install the new
126 * handlers and save the old ones. jvm uses sigaction().
127 * Leave the piece here just in case. */
128 oldhandler = call_os_signal(sig, disp, is_sigset);
129 save_signal_handler(sig, oldhandler);
130
131 /* Record the signals used by jvm */
132 jvmsigs |= MASK(sig);
133
134 signal_unlock();
135 return oldhandler;
136 } else {
137 /* jvm has no relation with this signal (yet). Install the
138 * the handler. */
139 oldhandler = call_os_signal(sig, disp, is_sigset);
140
141 signal_unlock();
142 return oldhandler;
143 }
144 }
145
146 sa_handler_t signal(int sig, sa_handler_t disp) {
147 return set_signal(sig, disp, false);
148 }
149
150 sa_handler_t sigset(int sig, sa_handler_t disp) {
151 return set_signal(sig, disp, true);
152 }
153
154 static int call_os_sigaction(int sig, const struct sigaction *act,
155 struct sigaction *oact) {
156 if (os_sigaction == NULL) {
157 // Aix: call functions directly instead of dlsym'ing them
158 os_sigaction = sigaction;
159 if (os_sigaction == NULL) {
160 printf("%s\n", dlerror());
161 exit(0);
162 }
163 }
164 return (*os_sigaction)(sig, act, oact);
165 }
166
167 int sigaction(int sig, const struct sigaction *act, struct sigaction *oact) {
168 int res;
169 bool sigused;
170 struct sigaction oldAct;
171
172 signal_lock();
173
174 sigused = (MASK(sig) & jvmsigs) != 0;
175 if (jvm_signal_installed && sigused) {
176 /* jvm has installed its signal handler for this signal. */
177 /* Save the handler. Don't really install it. */
178 if (oact != NULL) {
179 *oact = sact[sig];
180 }
181 if (act != NULL) {
182 sact[sig] = *act;
183 }
184
185 signal_unlock();
186 return 0;
187 } else if (jvm_signal_installing) {
188 /* jvm is installing its signal handlers. Install the new
189 * handlers and save the old ones. */
190 res = call_os_sigaction(sig, act, &oldAct);
191 sact[sig] = oldAct;
192 if (oact != NULL) {
193 *oact = oldAct;
194 }
195
196 /* Record the signals used by jvm */
197 jvmsigs |= MASK(sig);
198
199 signal_unlock();
200 return res;
201 } else {
202 /* jvm has no relation with this signal (yet). Install the
203 * the handler. */
204 res = call_os_sigaction(sig, act, oact);
205
206 signal_unlock();
207 return res;
208 }
209 }
210
211 /* The three functions for the jvm to call into */
212 void JVM_begin_signal_setting() {
213 signal_lock();
214 jvm_signal_installing = true;
215 tid = pthread_self();
216 signal_unlock();
217 }
218
219 void JVM_end_signal_setting() {
220 signal_lock();
221 jvm_signal_installed = true;
222 jvm_signal_installing = false;
223 pthread_cond_broadcast(&cond);
224 signal_unlock();
225 }
226
227 struct sigaction *JVM_get_signal_action(int sig) {
228 /* Does race condition make sense here? */
229 if ((MASK(sig) & jvmsigs) != 0) {
230 return &sact[sig];
231 }
232 return NULL;
233 }