Mercurial > hg > truffle
comparison src/os/bsd/vm/jsig.c @ 3960:f08d439fab8c
7089790: integrate bsd-port changes
Reviewed-by: kvn, twisti, jrose
Contributed-by: Kurt Miller <kurt@intricatesoftware.com>, Greg Lewis <glewis@eyesbeyond.com>, Jung-uk Kim <jkim@freebsd.org>, Christos Zoulas <christos@zoulas.com>, Landon Fuller <landonf@plausible.coop>, The FreeBSD Foundation <board@freebsdfoundation.org>, Michael Franz <mvfranz@gmail.com>, Roger Hoover <rhoover@apple.com>, Alexander Strange <astrange@apple.com>
author | never |
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date | Sun, 25 Sep 2011 16:03:29 -0700 |
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1 /* | |
2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. | |
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
20 * or visit www.oracle.com if you need additional information or have any | |
21 * questions. | |
22 * | |
23 */ | |
24 | |
25 /* CopyrightVersion 1.2 */ | |
26 | |
27 /* This is a special library that should be loaded before libc & | |
28 * libthread to interpose the signal handler installation functions: | |
29 * sigaction(), signal(), sigset(). | |
30 * Used for signal-chaining. See RFE 4381843. | |
31 */ | |
32 | |
33 #include <signal.h> | |
34 #include <dlfcn.h> | |
35 #include <pthread.h> | |
36 #include <stdio.h> | |
37 #include <stdlib.h> | |
38 #include <stdbool.h> | |
39 | |
40 #define MAXSIGNUM 32 | |
41 #define MASK(sig) ((unsigned int)1 << sig) | |
42 | |
43 static struct sigaction sact[MAXSIGNUM]; /* saved signal handlers */ | |
44 static unsigned int jvmsigs = 0; /* signals used by jvm */ | |
45 | |
46 /* used to synchronize the installation of signal handlers */ | |
47 static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; | |
48 static pthread_cond_t cond = PTHREAD_COND_INITIALIZER; | |
49 static pthread_t tid = 0; | |
50 | |
51 typedef void (*sa_handler_t)(int); | |
52 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); | |
53 typedef sa_handler_t (*signal_t)(int, sa_handler_t); | |
54 typedef int (*sigaction_t)(int, const struct sigaction *, struct sigaction *); | |
55 | |
56 static signal_t os_signal = 0; /* os's version of signal()/sigset() */ | |
57 static sigaction_t os_sigaction = 0; /* os's version of sigaction() */ | |
58 | |
59 static bool jvm_signal_installing = false; | |
60 static bool jvm_signal_installed = false; | |
61 | |
62 static void signal_lock() { | |
63 pthread_mutex_lock(&mutex); | |
64 /* When the jvm is installing its set of signal handlers, threads | |
65 * other than the jvm thread should wait */ | |
66 if (jvm_signal_installing) { | |
67 if (tid != pthread_self()) { | |
68 pthread_cond_wait(&cond, &mutex); | |
69 } | |
70 } | |
71 } | |
72 | |
73 static void signal_unlock() { | |
74 pthread_mutex_unlock(&mutex); | |
75 } | |
76 | |
77 static sa_handler_t call_os_signal(int sig, sa_handler_t disp, | |
78 bool is_sigset) { | |
79 if (os_signal == NULL) { | |
80 if (!is_sigset) { | |
81 os_signal = (signal_t)dlsym(RTLD_NEXT, "signal"); | |
82 } else { | |
83 os_signal = (signal_t)dlsym(RTLD_NEXT, "sigset"); | |
84 } | |
85 if (os_signal == NULL) { | |
86 printf("%s\n", dlerror()); | |
87 exit(0); | |
88 } | |
89 } | |
90 return (*os_signal)(sig, disp); | |
91 } | |
92 | |
93 static void save_signal_handler(int sig, sa_handler_t disp) { | |
94 sigset_t set; | |
95 sact[sig].sa_handler = disp; | |
96 sigemptyset(&set); | |
97 sact[sig].sa_mask = set; | |
98 sact[sig].sa_flags = 0; | |
99 } | |
100 | |
101 static sa_handler_t set_signal(int sig, sa_handler_t disp, bool is_sigset) { | |
102 sa_handler_t oldhandler; | |
103 bool sigused; | |
104 | |
105 signal_lock(); | |
106 | |
107 sigused = (MASK(sig) & jvmsigs) != 0; | |
108 if (jvm_signal_installed && sigused) { | |
109 /* jvm has installed its signal handler for this signal. */ | |
110 /* Save the handler. Don't really install it. */ | |
111 oldhandler = sact[sig].sa_handler; | |
112 save_signal_handler(sig, disp); | |
113 | |
114 signal_unlock(); | |
115 return oldhandler; | |
116 } else if (jvm_signal_installing) { | |
117 /* jvm is installing its signal handlers. Install the new | |
118 * handlers and save the old ones. jvm uses sigaction(). | |
119 * Leave the piece here just in case. */ | |
120 oldhandler = call_os_signal(sig, disp, is_sigset); | |
121 save_signal_handler(sig, oldhandler); | |
122 | |
123 /* Record the signals used by jvm */ | |
124 jvmsigs |= MASK(sig); | |
125 | |
126 signal_unlock(); | |
127 return oldhandler; | |
128 } else { | |
129 /* jvm has no relation with this signal (yet). Install the | |
130 * the handler. */ | |
131 oldhandler = call_os_signal(sig, disp, is_sigset); | |
132 | |
133 signal_unlock(); | |
134 return oldhandler; | |
135 } | |
136 } | |
137 | |
138 sa_handler_t signal(int sig, sa_handler_t disp) { | |
139 return set_signal(sig, disp, false); | |
140 } | |
141 | |
142 sa_handler_t sigset(int sig, sa_handler_t disp) { | |
143 printf("sigset() is not supported by BSD"); | |
144 exit(0); | |
145 } | |
146 | |
147 static int call_os_sigaction(int sig, const struct sigaction *act, | |
148 struct sigaction *oact) { | |
149 if (os_sigaction == NULL) { | |
150 os_sigaction = (sigaction_t)dlsym(RTLD_NEXT, "sigaction"); | |
151 if (os_sigaction == NULL) { | |
152 printf("%s\n", dlerror()); | |
153 exit(0); | |
154 } | |
155 } | |
156 return (*os_sigaction)(sig, act, oact); | |
157 } | |
158 | |
159 int sigaction(int sig, const struct sigaction *act, struct sigaction *oact) { | |
160 int res; | |
161 bool sigused; | |
162 struct sigaction oldAct; | |
163 | |
164 signal_lock(); | |
165 | |
166 sigused = (MASK(sig) & jvmsigs) != 0; | |
167 if (jvm_signal_installed && sigused) { | |
168 /* jvm has installed its signal handler for this signal. */ | |
169 /* Save the handler. Don't really install it. */ | |
170 if (oact != NULL) { | |
171 *oact = sact[sig]; | |
172 } | |
173 if (act != NULL) { | |
174 sact[sig] = *act; | |
175 } | |
176 | |
177 signal_unlock(); | |
178 return 0; | |
179 } else if (jvm_signal_installing) { | |
180 /* jvm is installing its signal handlers. Install the new | |
181 * handlers and save the old ones. */ | |
182 res = call_os_sigaction(sig, act, &oldAct); | |
183 sact[sig] = oldAct; | |
184 if (oact != NULL) { | |
185 *oact = oldAct; | |
186 } | |
187 | |
188 /* Record the signals used by jvm */ | |
189 jvmsigs |= MASK(sig); | |
190 | |
191 signal_unlock(); | |
192 return res; | |
193 } else { | |
194 /* jvm has no relation with this signal (yet). Install the | |
195 * the handler. */ | |
196 res = call_os_sigaction(sig, act, oact); | |
197 | |
198 signal_unlock(); | |
199 return res; | |
200 } | |
201 } | |
202 | |
203 /* The three functions for the jvm to call into */ | |
204 void JVM_begin_signal_setting() { | |
205 signal_lock(); | |
206 jvm_signal_installing = true; | |
207 tid = pthread_self(); | |
208 signal_unlock(); | |
209 } | |
210 | |
211 void JVM_end_signal_setting() { | |
212 signal_lock(); | |
213 jvm_signal_installed = true; | |
214 jvm_signal_installing = false; | |
215 pthread_cond_broadcast(&cond); | |
216 signal_unlock(); | |
217 } | |
218 | |
219 struct sigaction *JVM_get_signal_action(int sig) { | |
220 /* Does race condition make sense here? */ | |
221 if ((MASK(sig) & jvmsigs) != 0) { | |
222 return &sact[sig]; | |
223 } | |
224 return NULL; | |
225 } |