kern_thr.c revision 315949
1/*- 2 * Copyright (c) 2003, Jeffrey Roberson <jeff@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 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: stable/10/sys/kern/kern_thr.c 315949 2017-03-25 13:33:23Z badger $"); 29 30#include "opt_compat.h" 31#include "opt_posix.h" 32#include <sys/param.h> 33#include <sys/kernel.h> 34#include <sys/lock.h> 35#include <sys/mutex.h> 36#include <sys/priv.h> 37#include <sys/proc.h> 38#include <sys/posix4.h> 39#include <sys/ptrace.h> 40#include <sys/racct.h> 41#include <sys/resourcevar.h> 42#include <sys/rwlock.h> 43#include <sys/sched.h> 44#include <sys/sysctl.h> 45#include <sys/smp.h> 46#include <sys/syscallsubr.h> 47#include <sys/sysent.h> 48#include <sys/systm.h> 49#include <sys/sysproto.h> 50#include <sys/signalvar.h> 51#include <sys/sysctl.h> 52#include <sys/ucontext.h> 53#include <sys/thr.h> 54#include <sys/rtprio.h> 55#include <sys/umtx.h> 56#include <sys/limits.h> 57 58#include <machine/frame.h> 59 60#include <security/audit/audit.h> 61 62static SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0, 63 "thread allocation"); 64 65static int max_threads_per_proc = 1500; 66SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW, 67 &max_threads_per_proc, 0, "Limit on threads per proc"); 68 69static int max_threads_hits; 70SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD, 71 &max_threads_hits, 0, "kern.threads.max_threads_per_proc hit count"); 72 73#ifdef COMPAT_FREEBSD32 74 75static inline int 76suword_lwpid(void *addr, lwpid_t lwpid) 77{ 78 int error; 79 80 if (SV_CURPROC_FLAG(SV_LP64)) 81 error = suword(addr, lwpid); 82 else 83 error = suword32(addr, lwpid); 84 return (error); 85} 86 87#else 88#define suword_lwpid suword 89#endif 90 91/* 92 * System call interface. 93 */ 94 95struct thr_create_initthr_args { 96 ucontext_t ctx; 97 long *tid; 98}; 99 100static int 101thr_create_initthr(struct thread *td, void *thunk) 102{ 103 struct thr_create_initthr_args *args; 104 105 /* Copy out the child tid. */ 106 args = thunk; 107 if (args->tid != NULL && suword_lwpid(args->tid, td->td_tid)) 108 return (EFAULT); 109 110 return (set_mcontext(td, &args->ctx.uc_mcontext)); 111} 112 113int 114sys_thr_create(struct thread *td, struct thr_create_args *uap) 115 /* ucontext_t *ctx, long *id, int flags */ 116{ 117 struct thr_create_initthr_args args; 118 int error; 119 120 if ((error = copyin(uap->ctx, &args.ctx, sizeof(args.ctx)))) 121 return (error); 122 args.tid = uap->id; 123 return (thread_create(td, NULL, thr_create_initthr, &args)); 124} 125 126int 127sys_thr_new(struct thread *td, struct thr_new_args *uap) 128 /* struct thr_param * */ 129{ 130 struct thr_param param; 131 int error; 132 133 if (uap->param_size < 0 || uap->param_size > sizeof(param)) 134 return (EINVAL); 135 bzero(¶m, sizeof(param)); 136 if ((error = copyin(uap->param, ¶m, uap->param_size))) 137 return (error); 138 return (kern_thr_new(td, ¶m)); 139} 140 141static int 142thr_new_initthr(struct thread *td, void *thunk) 143{ 144 stack_t stack; 145 struct thr_param *param; 146 147 /* 148 * Here we copy out tid to two places, one for child and one 149 * for parent, because pthread can create a detached thread, 150 * if parent wants to safely access child tid, it has to provide 151 * its storage, because child thread may exit quickly and 152 * memory is freed before parent thread can access it. 153 */ 154 param = thunk; 155 if ((param->child_tid != NULL && 156 suword_lwpid(param->child_tid, td->td_tid)) || 157 (param->parent_tid != NULL && 158 suword_lwpid(param->parent_tid, td->td_tid))) 159 return (EFAULT); 160 161 /* Set up our machine context. */ 162 stack.ss_sp = param->stack_base; 163 stack.ss_size = param->stack_size; 164 /* Set upcall address to user thread entry function. */ 165 cpu_set_upcall_kse(td, param->start_func, param->arg, &stack); 166 /* Setup user TLS address and TLS pointer register. */ 167 return (cpu_set_user_tls(td, param->tls_base)); 168} 169 170int 171kern_thr_new(struct thread *td, struct thr_param *param) 172{ 173 struct rtprio rtp, *rtpp; 174 int error; 175 176 rtpp = NULL; 177 if (param->rtp != 0) { 178 error = copyin(param->rtp, &rtp, sizeof(struct rtprio)); 179 if (error) 180 return (error); 181 rtpp = &rtp; 182 } 183 return (thread_create(td, rtpp, thr_new_initthr, param)); 184} 185 186int 187thread_create(struct thread *td, struct rtprio *rtp, 188 int (*initialize_thread)(struct thread *, void *), void *thunk) 189{ 190 struct thread *newtd; 191 struct proc *p; 192 int error; 193 194 p = td->td_proc; 195 196 if (rtp != NULL) { 197 switch(rtp->type) { 198 case RTP_PRIO_REALTIME: 199 case RTP_PRIO_FIFO: 200 /* Only root can set scheduler policy */ 201 if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0) 202 return (EPERM); 203 if (rtp->prio > RTP_PRIO_MAX) 204 return (EINVAL); 205 break; 206 case RTP_PRIO_NORMAL: 207 rtp->prio = 0; 208 break; 209 default: 210 return (EINVAL); 211 } 212 } 213 214#ifdef RACCT 215 PROC_LOCK(td->td_proc); 216 error = racct_add(p, RACCT_NTHR, 1); 217 PROC_UNLOCK(td->td_proc); 218 if (error != 0) 219 return (EPROCLIM); 220#endif 221 222 /* Initialize our td */ 223 error = kern_thr_alloc(p, 0, &newtd); 224 if (error) 225 goto fail; 226 227 cpu_set_upcall(newtd, td); 228 229 bzero(&newtd->td_startzero, 230 __rangeof(struct thread, td_startzero, td_endzero)); 231 newtd->td_su = NULL; 232 newtd->td_sleeptimo = 0; 233 bcopy(&td->td_startcopy, &newtd->td_startcopy, 234 __rangeof(struct thread, td_startcopy, td_endcopy)); 235 newtd->td_proc = td->td_proc; 236 newtd->td_ucred = crhold(td->td_ucred); 237 newtd->td_dbg_sc_code = td->td_dbg_sc_code; 238 newtd->td_dbg_sc_narg = td->td_dbg_sc_narg; 239 240 error = initialize_thread(newtd, thunk); 241 if (error != 0) { 242 thread_free(newtd); 243 crfree(td->td_ucred); 244 goto fail; 245 } 246 247 PROC_LOCK(td->td_proc); 248 td->td_proc->p_flag |= P_HADTHREADS; 249 thread_link(newtd, p); 250 bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name)); 251 thread_lock(td); 252 /* let the scheduler know about these things. */ 253 sched_fork_thread(td, newtd); 254 thread_unlock(td); 255 if (P_SHOULDSTOP(p)) 256 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK; 257 if (p->p_ptevents & PTRACE_LWP) 258 newtd->td_dbgflags |= TDB_BORN; 259 PROC_UNLOCK(p); 260 261 tidhash_add(newtd); 262 263 thread_lock(newtd); 264 if (rtp != NULL) { 265 if (!(td->td_pri_class == PRI_TIMESHARE && 266 rtp->type == RTP_PRIO_NORMAL)) { 267 rtp_to_pri(rtp, newtd); 268 sched_prio(newtd, newtd->td_user_pri); 269 } /* ignore timesharing class */ 270 } 271 TD_SET_CAN_RUN(newtd); 272 sched_add(newtd, SRQ_BORING); 273 thread_unlock(newtd); 274 275 return (0); 276 277fail: 278#ifdef RACCT 279 if (racct_enable) { 280 PROC_LOCK(p); 281 racct_sub(p, RACCT_NTHR, 1); 282 PROC_UNLOCK(p); 283 } 284#endif 285 return (error); 286} 287 288int 289sys_thr_self(struct thread *td, struct thr_self_args *uap) 290 /* long *id */ 291{ 292 int error; 293 294 error = suword_lwpid(uap->id, (unsigned)td->td_tid); 295 if (error == -1) 296 return (EFAULT); 297 return (0); 298} 299 300int 301sys_thr_exit(struct thread *td, struct thr_exit_args *uap) 302 /* long *state */ 303{ 304 305 /* Signal userland that it can free the stack. */ 306 if ((void *)uap->state != NULL) { 307 suword_lwpid(uap->state, 1); 308 kern_umtx_wake(td, uap->state, INT_MAX, 0); 309 } 310 311 return (kern_thr_exit(td)); 312} 313 314int 315kern_thr_exit(struct thread *td) 316{ 317 struct proc *p; 318 319 p = td->td_proc; 320 321 /* 322 * If all of the threads in a process call this routine to 323 * exit (e.g. all threads call pthread_exit()), exactly one 324 * thread should return to the caller to terminate the process 325 * instead of the thread. 326 * 327 * Checking p_numthreads alone is not sufficient since threads 328 * might be committed to terminating while the PROC_LOCK is 329 * dropped in either ptracestop() or while removing this thread 330 * from the tidhash. Instead, the p_pendingexits field holds 331 * the count of threads in either of those states and a thread 332 * is considered the "last" thread if all of the other threads 333 * in a process are already terminating. 334 */ 335 PROC_LOCK(p); 336 if (p->p_numthreads == p->p_pendingexits + 1) { 337 /* 338 * Ignore attempts to shut down last thread in the 339 * proc. This will actually call _exit(2) in the 340 * usermode trampoline when it returns. 341 */ 342 PROC_UNLOCK(p); 343 return (0); 344 } 345 346 p->p_pendingexits++; 347 td->td_dbgflags |= TDB_EXIT; 348 if (p->p_ptevents & PTRACE_LWP) 349 ptracestop(td, SIGTRAP, NULL); 350 PROC_UNLOCK(p); 351 tidhash_remove(td); 352 PROC_LOCK(p); 353 p->p_pendingexits--; 354 355 /* 356 * The check above should prevent all other threads from this 357 * process from exiting while the PROC_LOCK is dropped, so 358 * there must be at least one other thread other than the 359 * current thread. 360 */ 361 KASSERT(p->p_numthreads > 1, ("too few threads")); 362 racct_sub(p, RACCT_NTHR, 1); 363 tdsigcleanup(td); 364 umtx_thread_exit(td); 365 PROC_SLOCK(p); 366 thread_stopped(p); 367 thread_exit(); 368 /* NOTREACHED */ 369} 370 371int 372sys_thr_kill(struct thread *td, struct thr_kill_args *uap) 373 /* long id, int sig */ 374{ 375 ksiginfo_t ksi; 376 struct thread *ttd; 377 struct proc *p; 378 int error; 379 380 p = td->td_proc; 381 ksiginfo_init(&ksi); 382 ksi.ksi_signo = uap->sig; 383 ksi.ksi_code = SI_LWP; 384 ksi.ksi_pid = p->p_pid; 385 ksi.ksi_uid = td->td_ucred->cr_ruid; 386 if (uap->id == -1) { 387 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) { 388 error = EINVAL; 389 } else { 390 error = ESRCH; 391 PROC_LOCK(p); 392 FOREACH_THREAD_IN_PROC(p, ttd) { 393 if (ttd != td) { 394 error = 0; 395 if (uap->sig == 0) 396 break; 397 tdksignal(ttd, uap->sig, &ksi); 398 } 399 } 400 PROC_UNLOCK(p); 401 } 402 } else { 403 error = 0; 404 ttd = tdfind((lwpid_t)uap->id, p->p_pid); 405 if (ttd == NULL) 406 return (ESRCH); 407 if (uap->sig == 0) 408 ; 409 else if (!_SIG_VALID(uap->sig)) 410 error = EINVAL; 411 else 412 tdksignal(ttd, uap->sig, &ksi); 413 PROC_UNLOCK(ttd->td_proc); 414 } 415 return (error); 416} 417 418int 419sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap) 420 /* pid_t pid, long id, int sig */ 421{ 422 ksiginfo_t ksi; 423 struct thread *ttd; 424 struct proc *p; 425 int error; 426 427 AUDIT_ARG_SIGNUM(uap->sig); 428 429 ksiginfo_init(&ksi); 430 ksi.ksi_signo = uap->sig; 431 ksi.ksi_code = SI_LWP; 432 ksi.ksi_pid = td->td_proc->p_pid; 433 ksi.ksi_uid = td->td_ucred->cr_ruid; 434 if (uap->id == -1) { 435 if ((p = pfind(uap->pid)) == NULL) 436 return (ESRCH); 437 AUDIT_ARG_PROCESS(p); 438 error = p_cansignal(td, p, uap->sig); 439 if (error) { 440 PROC_UNLOCK(p); 441 return (error); 442 } 443 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) { 444 error = EINVAL; 445 } else { 446 error = ESRCH; 447 FOREACH_THREAD_IN_PROC(p, ttd) { 448 if (ttd != td) { 449 error = 0; 450 if (uap->sig == 0) 451 break; 452 tdksignal(ttd, uap->sig, &ksi); 453 } 454 } 455 } 456 PROC_UNLOCK(p); 457 } else { 458 ttd = tdfind((lwpid_t)uap->id, uap->pid); 459 if (ttd == NULL) 460 return (ESRCH); 461 p = ttd->td_proc; 462 AUDIT_ARG_PROCESS(p); 463 error = p_cansignal(td, p, uap->sig); 464 if (uap->sig == 0) 465 ; 466 else if (!_SIG_VALID(uap->sig)) 467 error = EINVAL; 468 else 469 tdksignal(ttd, uap->sig, &ksi); 470 PROC_UNLOCK(p); 471 } 472 return (error); 473} 474 475int 476sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap) 477 /* const struct timespec *timeout */ 478{ 479 struct timespec ts, *tsp; 480 int error; 481 482 tsp = NULL; 483 if (uap->timeout != NULL) { 484 error = umtx_copyin_timeout(uap->timeout, &ts); 485 if (error != 0) 486 return (error); 487 tsp = &ts; 488 } 489 490 return (kern_thr_suspend(td, tsp)); 491} 492 493int 494kern_thr_suspend(struct thread *td, struct timespec *tsp) 495{ 496 struct proc *p = td->td_proc; 497 struct timeval tv; 498 int error = 0; 499 int timo = 0; 500 501 if (td->td_pflags & TDP_WAKEUP) { 502 td->td_pflags &= ~TDP_WAKEUP; 503 return (0); 504 } 505 506 if (tsp != NULL) { 507 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) 508 error = EWOULDBLOCK; 509 else { 510 TIMESPEC_TO_TIMEVAL(&tv, tsp); 511 timo = tvtohz(&tv); 512 } 513 } 514 515 PROC_LOCK(p); 516 if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0) 517 error = msleep((void *)td, &p->p_mtx, 518 PCATCH, "lthr", timo); 519 520 if (td->td_flags & TDF_THRWAKEUP) { 521 thread_lock(td); 522 td->td_flags &= ~TDF_THRWAKEUP; 523 thread_unlock(td); 524 PROC_UNLOCK(p); 525 return (0); 526 } 527 PROC_UNLOCK(p); 528 if (error == EWOULDBLOCK) 529 error = ETIMEDOUT; 530 else if (error == ERESTART) { 531 if (timo != 0) 532 error = EINTR; 533 } 534 return (error); 535} 536 537int 538sys_thr_wake(struct thread *td, struct thr_wake_args *uap) 539 /* long id */ 540{ 541 struct proc *p; 542 struct thread *ttd; 543 544 if (uap->id == td->td_tid) { 545 td->td_pflags |= TDP_WAKEUP; 546 return (0); 547 } 548 549 p = td->td_proc; 550 ttd = tdfind((lwpid_t)uap->id, p->p_pid); 551 if (ttd == NULL) 552 return (ESRCH); 553 thread_lock(ttd); 554 ttd->td_flags |= TDF_THRWAKEUP; 555 thread_unlock(ttd); 556 wakeup((void *)ttd); 557 PROC_UNLOCK(p); 558 return (0); 559} 560 561int 562sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap) 563{ 564 struct proc *p; 565 char name[MAXCOMLEN + 1]; 566 struct thread *ttd; 567 int error; 568 569 error = 0; 570 name[0] = '\0'; 571 if (uap->name != NULL) { 572 error = copyinstr(uap->name, name, sizeof(name), NULL); 573 if (error == ENAMETOOLONG) { 574 error = copyin(uap->name, name, sizeof(name) - 1); 575 name[sizeof(name) - 1] = '\0'; 576 } 577 if (error) 578 return (error); 579 } 580 p = td->td_proc; 581 ttd = tdfind((lwpid_t)uap->id, p->p_pid); 582 if (ttd == NULL) 583 return (ESRCH); 584 strcpy(ttd->td_name, name); 585#ifdef KTR 586 sched_clear_tdname(ttd); 587#endif 588 PROC_UNLOCK(p); 589 return (error); 590} 591 592int 593kern_thr_alloc(struct proc *p, int pages, struct thread **ntd) 594{ 595 596 /* Have race condition but it is cheap. */ 597 if (p->p_numthreads >= max_threads_per_proc) { 598 ++max_threads_hits; 599 return (EPROCLIM); 600 } 601 602 *ntd = thread_alloc(pages); 603 if (*ntd == NULL) 604 return (ENOMEM); 605 606 return (0); 607} 608