1 /* 2 * Copyright (c) 2005, David Xu <davidxu@freebsd.org> 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 unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include "namespace.h" 30 #include <sys/param.h> 31 #include <sys/types.h> 32 #include <sys/signalvar.h> 33 #include <signal.h> 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <unistd.h> 37 #include <string.h> 38 #include <pthread.h> 39 #include "un-namespace.h" 40 41 #include "thr_private.h" 42 43 /* #define DEBUG_SIGNAL */ 44 #ifdef DEBUG_SIGNAL 45 #define DBG_MSG stdout_debug 46 #else 47 #define DBG_MSG(x...) 48 #endif 49 50 extern int __pause(void); 51 int ___pause(void); 52 int _raise(int); 53 int __sigtimedwait(const sigset_t *set, siginfo_t *info, 54 const struct timespec * timeout); 55 int _sigtimedwait(const sigset_t *set, siginfo_t *info, 56 const struct timespec * timeout); 57 int __sigwaitinfo(const sigset_t *set, siginfo_t *info); 58 int _sigwaitinfo(const sigset_t *set, siginfo_t *info); 59 int __sigwait(const sigset_t *set, int *sig); 60 int _sigwait(const sigset_t *set, int *sig); 61 int __sigsuspend(const sigset_t *sigmask); 62 63 64 static void 65 sigcancel_handler(int sig __unused, 66 siginfo_t *info __unused, ucontext_t *ucp __unused) 67 { 68 struct pthread *curthread = _get_curthread(); 69 70 if (curthread->cancel_defer && curthread->cancel_pending) 71 thr_wake(curthread->tid); 72 _thr_ast(curthread); 73 } 74 75 void 76 _thr_ast(struct pthread *curthread) 77 { 78 if (!THR_IN_CRITICAL(curthread)) { 79 _thr_testcancel(curthread); 80 if (__predict_false((curthread->flags & 81 (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED)) 82 == THR_FLAGS_NEED_SUSPEND)) 83 _thr_suspend_check(curthread); 84 } 85 } 86 87 void 88 _thr_suspend_check(struct pthread *curthread) 89 { 90 long cycle; 91 int err; 92 93 err = errno; 94 /* 95 * Blocks SIGCANCEL which other threads must send. 96 */ 97 _thr_signal_block(curthread); 98 99 /* 100 * Increase critical_count, here we don't use THR_LOCK/UNLOCK 101 * because we are leaf code, we don't want to recursively call 102 * ourself. 103 */ 104 curthread->critical_count++; 105 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 106 while ((curthread->flags & (THR_FLAGS_NEED_SUSPEND | 107 THR_FLAGS_SUSPENDED)) == THR_FLAGS_NEED_SUSPEND) { 108 curthread->cycle++; 109 cycle = curthread->cycle; 110 111 /* Wake the thread suspending us. */ 112 _thr_umtx_wake(&curthread->cycle, INT_MAX); 113 114 /* 115 * if we are from pthread_exit, we don't want to 116 * suspend, just go and die. 117 */ 118 if (curthread->state == PS_DEAD) 119 break; 120 curthread->flags |= THR_FLAGS_SUSPENDED; 121 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 122 _thr_umtx_wait(&curthread->cycle, cycle, NULL); 123 THR_UMUTEX_LOCK(curthread, &(curthread)->lock); 124 curthread->flags &= ~THR_FLAGS_SUSPENDED; 125 } 126 THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock); 127 curthread->critical_count--; 128 129 /* 130 * Unblocks SIGCANCEL, it is possible a new SIGCANCEL is ready and 131 * a new signal frame will nest us, this seems a problem because 132 * stack will grow and overflow, but because kernel will automatically 133 * mask the SIGCANCEL when delivering the signal, so we at most only 134 * have one nesting signal frame, this should be fine. 135 */ 136 _thr_signal_unblock(curthread); 137 errno = err; 138 } 139 140 void 141 _thr_signal_init(void) 142 { 143 struct sigaction act; 144 145 /* Install cancel handler. */ 146 SIGEMPTYSET(act.sa_mask); 147 act.sa_flags = SA_SIGINFO | SA_RESTART; 148 act.sa_sigaction = (__siginfohandler_t *)&sigcancel_handler; 149 __sys_sigaction(SIGCANCEL, &act, NULL); 150 } 151 152 void 153 _thr_signal_deinit(void) 154 { 155 } 156 157 __weak_reference(___pause, pause); 158 159 int 160 ___pause(void) 161 { 162 struct pthread *curthread = _get_curthread(); 163 int ret; 164 165 _thr_cancel_enter(curthread); 166 ret = __pause(); 167 _thr_cancel_leave(curthread); 168 169 return ret; 170 } 171 172 __weak_reference(_raise, raise); 173 174 int 175 _raise(int sig) 176 { 177 int ret; 178 179 if (!_thr_isthreaded()) 180 ret = kill(getpid(), sig); 181 else 182 ret = _thr_send_sig(_get_curthread(), sig); 183 return (ret); 184 } 185 186 __weak_reference(_sigaction, sigaction); 187 188 int 189 _sigaction(int sig, const struct sigaction * act, struct sigaction * oact) 190 { 191 /* Check if the signal number is out of range: */ 192 if (sig < 1 || sig > _SIG_MAXSIG || sig == SIGCANCEL) { 193 /* Return an invalid argument: */ 194 errno = EINVAL; 195 return (-1); 196 } 197 198 return __sys_sigaction(sig, act, oact); 199 } 200 201 __weak_reference(_sigprocmask, sigprocmask); 202 203 int 204 _sigprocmask(int how, const sigset_t *set, sigset_t *oset) 205 { 206 const sigset_t *p = set; 207 sigset_t newset; 208 209 if (how != SIG_UNBLOCK) { 210 if (set != NULL) { 211 newset = *set; 212 SIGDELSET(newset, SIGCANCEL); 213 p = &newset; 214 } 215 } 216 return (__sys_sigprocmask(how, p, oset)); 217 } 218 219 __weak_reference(_pthread_sigmask, pthread_sigmask); 220 221 int 222 _pthread_sigmask(int how, const sigset_t *set, sigset_t *oset) 223 { 224 if (_sigprocmask(how, set, oset)) 225 return (errno); 226 return (0); 227 } 228 229 __weak_reference(__sigsuspend, sigsuspend); 230 231 int 232 _sigsuspend(const sigset_t * set) 233 { 234 sigset_t newset; 235 const sigset_t *pset; 236 int ret; 237 238 if (SIGISMEMBER(*set, SIGCANCEL)) { 239 newset = *set; 240 SIGDELSET(newset, SIGCANCEL); 241 pset = &newset; 242 } else 243 pset = set; 244 245 ret = __sys_sigsuspend(pset); 246 247 return (ret); 248 } 249 250 int 251 __sigsuspend(const sigset_t * set) 252 { 253 struct pthread *curthread = _get_curthread(); 254 sigset_t newset; 255 const sigset_t *pset; 256 int ret; 257 258 if (SIGISMEMBER(*set, SIGCANCEL)) { 259 newset = *set; 260 SIGDELSET(newset, SIGCANCEL); 261 pset = &newset; 262 } else 263 pset = set; 264 265 _thr_cancel_enter(curthread); 266 ret = __sys_sigsuspend(pset); 267 _thr_cancel_leave(curthread); 268 269 return (ret); 270 } 271 272 __weak_reference(__sigwait, sigwait); 273 __weak_reference(__sigtimedwait, sigtimedwait); 274 __weak_reference(__sigwaitinfo, sigwaitinfo); 275 276 int 277 _sigtimedwait(const sigset_t *set, siginfo_t *info, 278 const struct timespec * timeout) 279 { 280 sigset_t newset; 281 const sigset_t *pset; 282 int ret; 283 284 if (SIGISMEMBER(*set, SIGCANCEL)) { 285 newset = *set; 286 SIGDELSET(newset, SIGCANCEL); 287 pset = &newset; 288 } else 289 pset = set; 290 ret = __sys_sigtimedwait(pset, info, timeout); 291 return (ret); 292 } 293 294 int 295 __sigtimedwait(const sigset_t *set, siginfo_t *info, 296 const struct timespec * timeout) 297 { 298 struct pthread *curthread = _get_curthread(); 299 sigset_t newset; 300 const sigset_t *pset; 301 int ret; 302 303 if (SIGISMEMBER(*set, SIGCANCEL)) { 304 newset = *set; 305 SIGDELSET(newset, SIGCANCEL); 306 pset = &newset; 307 } else 308 pset = set; 309 _thr_cancel_enter(curthread); 310 ret = __sys_sigtimedwait(pset, info, timeout); 311 _thr_cancel_leave(curthread); 312 return (ret); 313 } 314 315 int 316 _sigwaitinfo(const sigset_t *set, siginfo_t *info) 317 { 318 sigset_t newset; 319 const sigset_t *pset; 320 int ret; 321 322 if (SIGISMEMBER(*set, SIGCANCEL)) { 323 newset = *set; 324 SIGDELSET(newset, SIGCANCEL); 325 pset = &newset; 326 } else 327 pset = set; 328 329 ret = __sys_sigwaitinfo(pset, info); 330 return (ret); 331 } 332 333 int 334 __sigwaitinfo(const sigset_t *set, siginfo_t *info) 335 { 336 struct pthread *curthread = _get_curthread(); 337 sigset_t newset; 338 const sigset_t *pset; 339 int ret; 340 341 if (SIGISMEMBER(*set, SIGCANCEL)) { 342 newset = *set; 343 SIGDELSET(newset, SIGCANCEL); 344 pset = &newset; 345 } else 346 pset = set; 347 348 _thr_cancel_enter(curthread); 349 ret = __sys_sigwaitinfo(pset, info); 350 _thr_cancel_leave(curthread); 351 return (ret); 352 } 353 354 int 355 _sigwait(const sigset_t *set, int *sig) 356 { 357 sigset_t newset; 358 const sigset_t *pset; 359 int ret; 360 361 if (SIGISMEMBER(*set, SIGCANCEL)) { 362 newset = *set; 363 SIGDELSET(newset, SIGCANCEL); 364 pset = &newset; 365 } else 366 pset = set; 367 368 ret = __sys_sigwait(pset, sig); 369 return (ret); 370 } 371 372 int 373 __sigwait(const sigset_t *set, int *sig) 374 { 375 struct pthread *curthread = _get_curthread(); 376 sigset_t newset; 377 const sigset_t *pset; 378 int ret; 379 380 if (SIGISMEMBER(*set, SIGCANCEL)) { 381 newset = *set; 382 SIGDELSET(newset, SIGCANCEL); 383 pset = &newset; 384 } else 385 pset = set; 386 387 _thr_cancel_enter(curthread); 388 ret = __sys_sigwait(pset, sig); 389 _thr_cancel_leave(curthread); 390 return (ret); 391 } 392