Mercurial > hg > graal-jvmci-8
annotate src/os/bsd/vm/jsig.c @ 24234:ea6f94ab283b default tip
Added tag jvmci-0.36 for changeset 8128b98d4736
| author | Gilles Duboscq <gilles.m.duboscq@oracle.com> |
|---|---|
| date | Mon, 18 Sep 2017 18:49:45 +0200 |
| parents | 79841fc03469 |
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| rev | line source |
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| 3960 | 1 /* |
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2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved. |
| 3960 | 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> | |
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39 #include <string.h> |
| 3960 | 40 |
| 41 #define MAXSIGNUM 32 | |
| 42 #define MASK(sig) ((unsigned int)1 << sig) | |
| 43 | |
| 44 static struct sigaction sact[MAXSIGNUM]; /* saved signal handlers */ | |
| 45 static unsigned int jvmsigs = 0; /* signals used by jvm */ | |
| 46 | |
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47 static pthread_key_t reentry_flag_key; |
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48 static pthread_once_t reentry_key_init_once = PTHREAD_ONCE_INIT; |
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49 |
| 3960 | 50 /* used to synchronize the installation of signal handlers */ |
| 51 static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; | |
| 52 static pthread_cond_t cond = PTHREAD_COND_INITIALIZER; | |
| 53 static pthread_t tid = 0; | |
| 54 | |
| 55 typedef void (*sa_handler_t)(int); | |
| 56 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); | |
| 57 typedef sa_handler_t (*signal_t)(int, sa_handler_t); | |
| 58 typedef int (*sigaction_t)(int, const struct sigaction *, struct sigaction *); | |
| 59 | |
| 60 static signal_t os_signal = 0; /* os's version of signal()/sigset() */ | |
| 61 static sigaction_t os_sigaction = 0; /* os's version of sigaction() */ | |
| 62 | |
| 63 static bool jvm_signal_installing = false; | |
| 64 static bool jvm_signal_installed = false; | |
| 65 | |
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66 #define check_status(cmd) \ |
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67 do { \ |
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68 int status = (cmd); \ |
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69 if (status != 0) { \ |
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70 printf("error %s (%d) in " #cmd "\n", strerror(status), status); \ |
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71 exit(1); \ |
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72 } \ |
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73 } while (0) |
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74 |
| 3960 | 75 static void signal_lock() { |
| 76 pthread_mutex_lock(&mutex); | |
| 77 /* When the jvm is installing its set of signal handlers, threads | |
| 78 * other than the jvm thread should wait */ | |
| 79 if (jvm_signal_installing) { | |
| 80 if (tid != pthread_self()) { | |
| 81 pthread_cond_wait(&cond, &mutex); | |
| 82 } | |
| 83 } | |
| 84 } | |
| 85 | |
| 86 static void signal_unlock() { | |
| 87 pthread_mutex_unlock(&mutex); | |
| 88 } | |
| 89 | |
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90 static void reentry_tls_init() { |
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91 // value for reentry_flag_key will default to NULL (false) |
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92 check_status(pthread_key_create(&reentry_flag_key, NULL)); |
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93 } |
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94 |
| 3960 | 95 static sa_handler_t call_os_signal(int sig, sa_handler_t disp, |
| 96 bool is_sigset) { | |
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97 sa_handler_t res; |
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98 |
| 3960 | 99 if (os_signal == NULL) { |
| 100 if (!is_sigset) { | |
| 101 os_signal = (signal_t)dlsym(RTLD_NEXT, "signal"); | |
| 102 } else { | |
| 103 os_signal = (signal_t)dlsym(RTLD_NEXT, "sigset"); | |
| 104 } | |
| 105 if (os_signal == NULL) { | |
| 106 printf("%s\n", dlerror()); | |
| 107 exit(0); | |
| 108 } | |
| 109 } | |
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110 check_status(pthread_once(&reentry_key_init_once, reentry_tls_init)); |
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111 // set reentry_flag_key to non-NULL to show reentry |
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112 check_status(pthread_setspecific(reentry_flag_key, &res)); |
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113 res = (*os_signal)(sig, disp); |
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114 check_status(pthread_setspecific(reentry_flag_key, NULL)); |
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115 return res; |
| 3960 | 116 } |
| 117 | |
| 118 static void save_signal_handler(int sig, sa_handler_t disp) { | |
| 119 sigset_t set; | |
| 120 sact[sig].sa_handler = disp; | |
| 121 sigemptyset(&set); | |
| 122 sact[sig].sa_mask = set; | |
| 123 sact[sig].sa_flags = 0; | |
| 124 } | |
| 125 | |
| 126 static sa_handler_t set_signal(int sig, sa_handler_t disp, bool is_sigset) { | |
| 127 sa_handler_t oldhandler; | |
| 128 bool sigused; | |
| 129 | |
| 130 signal_lock(); | |
| 131 | |
| 132 sigused = (MASK(sig) & jvmsigs) != 0; | |
| 133 if (jvm_signal_installed && sigused) { | |
| 134 /* jvm has installed its signal handler for this signal. */ | |
| 135 /* Save the handler. Don't really install it. */ | |
| 136 oldhandler = sact[sig].sa_handler; | |
| 137 save_signal_handler(sig, disp); | |
| 138 | |
| 139 signal_unlock(); | |
| 140 return oldhandler; | |
| 141 } else if (jvm_signal_installing) { | |
| 142 /* jvm is installing its signal handlers. Install the new | |
| 143 * handlers and save the old ones. jvm uses sigaction(). | |
| 144 * Leave the piece here just in case. */ | |
| 145 oldhandler = call_os_signal(sig, disp, is_sigset); | |
| 146 save_signal_handler(sig, oldhandler); | |
| 147 | |
| 148 /* Record the signals used by jvm */ | |
| 149 jvmsigs |= MASK(sig); | |
| 150 | |
| 151 signal_unlock(); | |
| 152 return oldhandler; | |
| 153 } else { | |
| 154 /* jvm has no relation with this signal (yet). Install the | |
| 155 * the handler. */ | |
| 156 oldhandler = call_os_signal(sig, disp, is_sigset); | |
| 157 | |
| 158 signal_unlock(); | |
| 159 return oldhandler; | |
| 160 } | |
| 161 } | |
| 162 | |
| 163 sa_handler_t signal(int sig, sa_handler_t disp) { | |
| 164 return set_signal(sig, disp, false); | |
| 165 } | |
| 166 | |
| 167 sa_handler_t sigset(int sig, sa_handler_t disp) { | |
| 168 printf("sigset() is not supported by BSD"); | |
| 169 exit(0); | |
| 170 } | |
| 171 | |
| 172 static int call_os_sigaction(int sig, const struct sigaction *act, | |
| 173 struct sigaction *oact) { | |
| 174 if (os_sigaction == NULL) { | |
| 175 os_sigaction = (sigaction_t)dlsym(RTLD_NEXT, "sigaction"); | |
| 176 if (os_sigaction == NULL) { | |
| 177 printf("%s\n", dlerror()); | |
| 178 exit(0); | |
| 179 } | |
| 180 } | |
| 181 return (*os_sigaction)(sig, act, oact); | |
| 182 } | |
| 183 | |
| 184 int sigaction(int sig, const struct sigaction *act, struct sigaction *oact) { | |
| 185 int res; | |
| 186 bool sigused; | |
| 187 struct sigaction oldAct; | |
| 188 | |
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189 check_status(pthread_once(&reentry_key_init_once, reentry_tls_init)); |
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190 if (pthread_getspecific(reentry_flag_key) != NULL) { |
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191 return call_os_sigaction(sig, act, oact); |
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192 } |
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193 |
| 3960 | 194 signal_lock(); |
| 195 | |
| 196 sigused = (MASK(sig) & jvmsigs) != 0; | |
| 197 if (jvm_signal_installed && sigused) { | |
| 198 /* jvm has installed its signal handler for this signal. */ | |
| 199 /* Save the handler. Don't really install it. */ | |
| 200 if (oact != NULL) { | |
| 201 *oact = sact[sig]; | |
| 202 } | |
| 203 if (act != NULL) { | |
| 204 sact[sig] = *act; | |
| 205 } | |
| 206 | |
| 207 signal_unlock(); | |
| 208 return 0; | |
| 209 } else if (jvm_signal_installing) { | |
| 210 /* jvm is installing its signal handlers. Install the new | |
| 211 * handlers and save the old ones. */ | |
| 212 res = call_os_sigaction(sig, act, &oldAct); | |
| 213 sact[sig] = oldAct; | |
| 214 if (oact != NULL) { | |
| 215 *oact = oldAct; | |
| 216 } | |
| 217 | |
| 218 /* Record the signals used by jvm */ | |
| 219 jvmsigs |= MASK(sig); | |
| 220 | |
| 221 signal_unlock(); | |
| 222 return res; | |
| 223 } else { | |
| 224 /* jvm has no relation with this signal (yet). Install the | |
| 225 * the handler. */ | |
| 226 res = call_os_sigaction(sig, act, oact); | |
| 227 | |
| 228 signal_unlock(); | |
| 229 return res; | |
| 230 } | |
| 231 } | |
| 232 | |
| 233 /* The three functions for the jvm to call into */ | |
| 234 void JVM_begin_signal_setting() { | |
| 235 signal_lock(); | |
| 236 jvm_signal_installing = true; | |
| 237 tid = pthread_self(); | |
| 238 signal_unlock(); | |
| 239 } | |
| 240 | |
| 241 void JVM_end_signal_setting() { | |
| 242 signal_lock(); | |
| 243 jvm_signal_installed = true; | |
| 244 jvm_signal_installing = false; | |
| 245 pthread_cond_broadcast(&cond); | |
| 246 signal_unlock(); | |
| 247 } | |
| 248 | |
| 249 struct sigaction *JVM_get_signal_action(int sig) { | |
| 250 /* Does race condition make sense here? */ | |
| 251 if ((MASK(sig) & jvmsigs) != 0) { | |
| 252 return &sact[sig]; | |
| 253 } | |
| 254 return NULL; | |
| 255 } |