1 /* 2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by John Birrell. 16 * 4. Neither the name of the author nor the names of any co-contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * $DragonFly: src/lib/libthread_xu/thread/thr_sig.c,v 1.5 2006/03/19 13:07:12 davidxu Exp $ 33 */ 34 35 #include <sys/param.h> 36 #include <sys/signalvar.h> 37 38 #include <machine/tls.h> 39 40 #include <signal.h> 41 #include <errno.h> 42 #include <fcntl.h> 43 #include <unistd.h> 44 #include <string.h> 45 #include <pthread.h> 46 47 #include "thr_private.h" 48 49 /* #define DEBUG_SIGNAL */ 50 #ifdef DEBUG_SIGNAL 51 #define DBG_MSG stdout_debug 52 #else 53 #define DBG_MSG(x...) 54 #endif 55 56 static void 57 sigcancel_handler(int sig, siginfo_t *info, ucontext_t *ucp) 58 { 59 struct pthread *curthread = tls_get_curthread(); 60 61 if (curthread->cancelflags & THR_CANCEL_AT_POINT) 62 pthread_testcancel(); 63 _thr_ast(curthread); 64 } 65 66 void 67 _thr_ast(struct pthread *curthread) 68 { 69 if (!THR_IN_CRITICAL(curthread)) { 70 if (__predict_false((curthread->flags & 71 (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED)) 72 == THR_FLAGS_NEED_SUSPEND)) 73 _thr_suspend_check(curthread); 74 } 75 } 76 77 void 78 _thr_suspend_check(struct pthread *curthread) 79 { 80 umtx_t cycle; 81 82 /* 83 * Blocks SIGCANCEL which other threads must send. 84 */ 85 _thr_signal_block(curthread); 86 87 /* 88 * Increase critical_count, here we don't use THR_LOCK/UNLOCK 89 * because we are leaf code, we don't want to recursively call 90 * ourself. 91 */ 92 curthread->critical_count++; 93 THR_UMTX_LOCK(curthread, &(curthread)->lock); 94 while ((curthread->flags & (THR_FLAGS_NEED_SUSPEND | 95 THR_FLAGS_SUSPENDED)) == THR_FLAGS_NEED_SUSPEND) { 96 curthread->cycle++; 97 cycle = curthread->cycle; 98 99 /* Wake the thread suspending us. */ 100 _thr_umtx_wake(&curthread->cycle, INT_MAX); 101 102 /* 103 * if we are from pthread_exit, we don't want to 104 * suspend, just go and die. 105 */ 106 if (curthread->state == PS_DEAD) 107 break; 108 curthread->flags |= THR_FLAGS_SUSPENDED; 109 THR_UMTX_UNLOCK(curthread, &(curthread)->lock); 110 _thr_umtx_wait(&curthread->cycle, cycle, NULL, 0); 111 THR_UMTX_LOCK(curthread, &(curthread)->lock); 112 curthread->flags &= ~THR_FLAGS_SUSPENDED; 113 } 114 THR_UMTX_UNLOCK(curthread, &(curthread)->lock); 115 curthread->critical_count--; 116 117 _thr_signal_unblock(curthread); 118 } 119 120 void 121 _thr_signal_init(void) 122 { 123 struct sigaction act; 124 125 /* Install cancel handler. */ 126 SIGEMPTYSET(act.sa_mask); 127 act.sa_flags = SA_SIGINFO | SA_RESTART; 128 act.sa_sigaction = (__siginfohandler_t *)&sigcancel_handler; 129 __sys_sigaction(SIGCANCEL, &act, NULL); 130 } 131 132 void 133 _thr_signal_deinit(void) 134 { 135 } 136 137 __weak_reference(_sigaction, sigaction); 138 139 int 140 _sigaction(int sig, const struct sigaction * act, struct sigaction * oact) 141 { 142 /* Check if the signal number is out of range: */ 143 if (sig < 1 || sig > _SIG_MAXSIG || sig == SIGCANCEL) { 144 /* Return an invalid argument: */ 145 errno = EINVAL; 146 return (-1); 147 } 148 149 return __sys_sigaction(sig, act, oact); 150 } 151 152 __weak_reference(_sigprocmask, sigprocmask); 153 154 int 155 _sigprocmask(int how, const sigset_t *set, sigset_t *oset) 156 { 157 const sigset_t *p = set; 158 sigset_t newset; 159 160 if (how != SIG_UNBLOCK) { 161 if (set != NULL) { 162 newset = *set; 163 SIGDELSET(newset, SIGCANCEL); 164 p = &newset; 165 } 166 } 167 return (__sys_sigprocmask(how, p, oset)); 168 } 169 170 __weak_reference(_pthread_sigmask, pthread_sigmask); 171 172 int 173 _pthread_sigmask(int how, const sigset_t *set, sigset_t *oset) 174 { 175 if (_sigprocmask(how, set, oset)) 176 return (errno); 177 return (0); 178 } 179 180 __weak_reference(_sigsuspend, sigsuspend); 181 182 int 183 _sigsuspend(const sigset_t * set) 184 { 185 struct pthread *curthread = tls_get_curthread(); 186 sigset_t newset; 187 const sigset_t *pset; 188 int oldcancel; 189 int ret; 190 191 if (SIGISMEMBER(*set, SIGCANCEL)) { 192 newset = *set; 193 SIGDELSET(newset, SIGCANCEL); 194 pset = &newset; 195 } else 196 pset = set; 197 198 oldcancel = _thr_cancel_enter(curthread); 199 ret = __sys_sigsuspend(pset); 200 _thr_cancel_leave(curthread, oldcancel); 201 202 return (ret); 203 } 204 205 __weak_reference(__sigwait, sigwait); 206 __weak_reference(__sigtimedwait, sigtimedwait); 207 __weak_reference(__sigwaitinfo, sigwaitinfo); 208 209 int 210 __sigtimedwait(const sigset_t *set, siginfo_t *info, 211 const struct timespec * timeout) 212 { 213 struct pthread *curthread = tls_get_curthread(); 214 sigset_t newset; 215 const sigset_t *pset; 216 int oldcancel; 217 int ret; 218 219 if (SIGISMEMBER(*set, SIGCANCEL)) { 220 newset = *set; 221 SIGDELSET(newset, SIGCANCEL); 222 pset = &newset; 223 } else 224 pset = set; 225 oldcancel = _thr_cancel_enter(curthread); 226 ret = __sys_sigtimedwait(pset, info, timeout); 227 _thr_cancel_leave(curthread, oldcancel); 228 return (ret); 229 } 230 231 int 232 __sigwaitinfo(const sigset_t *set, siginfo_t *info) 233 { 234 struct pthread *curthread = tls_get_curthread(); 235 sigset_t newset; 236 const sigset_t *pset; 237 int oldcancel; 238 int ret; 239 240 if (SIGISMEMBER(*set, SIGCANCEL)) { 241 newset = *set; 242 SIGDELSET(newset, SIGCANCEL); 243 pset = &newset; 244 } else 245 pset = set; 246 247 oldcancel = _thr_cancel_enter(curthread); 248 ret = __sys_sigwaitinfo(pset, info); 249 _thr_cancel_leave(curthread, oldcancel); 250 return (ret); 251 } 252 253 int 254 __sigwait(const sigset_t *set, int *sig) 255 { 256 int s; 257 258 s = __sigwaitinfo(set, NULL); 259 if (s > 0) { 260 *sig = s; 261 return (0); 262 } 263 return (errno); 264 } 265