1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2003, Jeffrey Roberson <jeff@freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice unmodified, this list of conditions, and the following
12 * disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #include "opt_posix.h"
31 #include "opt_hwpmc_hooks.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/umtxvar.h>
56 #include <sys/limits.h>
57 #ifdef HWPMC_HOOKS
58 #include <sys/pmckern.h>
59 #endif
60
61 #include <machine/frame.h>
62
63 #include <security/audit/audit.h>
64
65 static SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
66 "thread allocation");
67
68 int max_threads_per_proc = 1500;
69 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
70 &max_threads_per_proc, 0, "Limit on threads per proc");
71
72 static int max_threads_hits;
73 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
74 &max_threads_hits, 0, "kern.threads.max_threads_per_proc hit count");
75
76 #ifdef COMPAT_FREEBSD32
77
78 static inline int
suword_lwpid(void * addr,lwpid_t lwpid)79 suword_lwpid(void *addr, lwpid_t lwpid)
80 {
81 int error;
82
83 if (SV_CURPROC_FLAG(SV_LP64))
84 error = suword(addr, lwpid);
85 else
86 error = suword32(addr, lwpid);
87 return (error);
88 }
89
90 #else
91 #define suword_lwpid suword
92 #endif
93
94 /*
95 * System call interface.
96 */
97
98 struct thr_create_initthr_args {
99 ucontext_t ctx;
100 long *tid;
101 };
102
103 static int
thr_create_initthr(struct thread * td,void * thunk)104 thr_create_initthr(struct thread *td, void *thunk)
105 {
106 struct thr_create_initthr_args *args;
107
108 /* Copy out the child tid. */
109 args = thunk;
110 if (args->tid != NULL && suword_lwpid(args->tid, td->td_tid))
111 return (EFAULT);
112
113 return (set_mcontext(td, &args->ctx.uc_mcontext));
114 }
115
116 int
sys_thr_create(struct thread * td,struct thr_create_args * uap)117 sys_thr_create(struct thread *td, struct thr_create_args *uap)
118 /* ucontext_t *ctx, long *id, int flags */
119 {
120 struct thr_create_initthr_args args;
121 int error;
122
123 if ((error = copyin(uap->ctx, &args.ctx, sizeof(args.ctx))))
124 return (error);
125 args.tid = uap->id;
126 return (thread_create(td, NULL, thr_create_initthr, &args));
127 }
128
129 int
sys_thr_new(struct thread * td,struct thr_new_args * uap)130 sys_thr_new(struct thread *td, struct thr_new_args *uap)
131 /* struct thr_param * */
132 {
133 struct thr_param param;
134 int error;
135
136 if (uap->param_size < 0 || uap->param_size > sizeof(param))
137 return (EINVAL);
138 bzero(¶m, sizeof(param));
139 if ((error = copyin(uap->param, ¶m, uap->param_size)))
140 return (error);
141 return (kern_thr_new(td, ¶m));
142 }
143
144 static int
thr_new_initthr(struct thread * td,void * thunk)145 thr_new_initthr(struct thread *td, void *thunk)
146 {
147 stack_t stack;
148 struct thr_param *param;
149 int error;
150
151 /*
152 * Here we copy out tid to two places, one for child and one
153 * for parent, because pthread can create a detached thread,
154 * if parent wants to safely access child tid, it has to provide
155 * its storage, because child thread may exit quickly and
156 * memory is freed before parent thread can access it.
157 */
158 param = thunk;
159 if ((param->child_tid != NULL &&
160 suword_lwpid(param->child_tid, td->td_tid)) ||
161 (param->parent_tid != NULL &&
162 suword_lwpid(param->parent_tid, td->td_tid)))
163 return (EFAULT);
164
165 /* Set up our machine context. */
166 stack.ss_sp = param->stack_base;
167 stack.ss_size = param->stack_size;
168 /* Set upcall address to user thread entry function. */
169 error = cpu_set_upcall(td, param->start_func, param->arg, &stack);
170 if (error != 0)
171 return (error);
172 /* Setup user TLS address and TLS pointer register. */
173 return (cpu_set_user_tls(td, param->tls_base));
174 }
175
176 int
kern_thr_new(struct thread * td,struct thr_param * param)177 kern_thr_new(struct thread *td, struct thr_param *param)
178 {
179 struct rtprio rtp, *rtpp;
180 int error;
181
182 rtpp = NULL;
183 if (param->rtp != 0) {
184 error = copyin(param->rtp, &rtp, sizeof(struct rtprio));
185 if (error)
186 return (error);
187 rtpp = &rtp;
188 }
189 return (thread_create(td, rtpp, thr_new_initthr, param));
190 }
191
192 int
thread_create(struct thread * td,struct rtprio * rtp,int (* initialize_thread)(struct thread *,void *),void * thunk)193 thread_create(struct thread *td, struct rtprio *rtp,
194 int (*initialize_thread)(struct thread *, void *), void *thunk)
195 {
196 struct thread *newtd;
197 struct proc *p;
198 int error;
199
200 p = td->td_proc;
201
202 if (rtp != NULL) {
203 switch(rtp->type) {
204 case RTP_PRIO_REALTIME:
205 case RTP_PRIO_FIFO:
206 /* Only root can set scheduler policy */
207 if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0)
208 return (EPERM);
209 if (rtp->prio > RTP_PRIO_MAX)
210 return (EINVAL);
211 break;
212 case RTP_PRIO_NORMAL:
213 rtp->prio = 0;
214 break;
215 default:
216 return (EINVAL);
217 }
218 }
219
220 #ifdef RACCT
221 if (racct_enable) {
222 PROC_LOCK(p);
223 error = racct_add(p, RACCT_NTHR, 1);
224 PROC_UNLOCK(p);
225 if (error != 0)
226 return (EPROCLIM);
227 }
228 #endif
229
230 /* Initialize our td */
231 error = kern_thr_alloc(p, 0, &newtd);
232 if (error)
233 goto fail;
234
235 bzero(&newtd->td_startzero,
236 __rangeof(struct thread, td_startzero, td_endzero));
237 bcopy(&td->td_startcopy, &newtd->td_startcopy,
238 __rangeof(struct thread, td_startcopy, td_endcopy));
239 newtd->td_proc = td->td_proc;
240 newtd->td_rb_list = newtd->td_rbp_list = newtd->td_rb_inact = 0;
241 thread_cow_get(newtd, td);
242
243 cpu_copy_thread(newtd, td);
244
245 error = initialize_thread(newtd, thunk);
246 if (error != 0) {
247 thread_cow_free(newtd);
248 thread_free(newtd);
249 goto fail;
250 }
251
252 PROC_LOCK(p);
253 p->p_flag |= P_HADTHREADS;
254 thread_link(newtd, p);
255 bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
256 thread_lock(td);
257 /* let the scheduler know about these things. */
258 sched_fork_thread(td, newtd);
259 thread_unlock(td);
260 if (P_SHOULDSTOP(p))
261 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
262 if (p->p_ptevents & PTRACE_LWP)
263 newtd->td_dbgflags |= TDB_BORN;
264
265 PROC_UNLOCK(p);
266 #ifdef HWPMC_HOOKS
267 if (PMC_PROC_IS_USING_PMCS(p))
268 PMC_CALL_HOOK(newtd, PMC_FN_THR_CREATE, NULL);
269 else if (PMC_SYSTEM_SAMPLING_ACTIVE())
270 PMC_CALL_HOOK_UNLOCKED(newtd, PMC_FN_THR_CREATE_LOG, NULL);
271 #endif
272
273 tidhash_add(newtd);
274
275 /* ignore timesharing class */
276 if (rtp != NULL && !(td->td_pri_class == PRI_TIMESHARE &&
277 rtp->type == RTP_PRIO_NORMAL))
278 rtp_to_pri(rtp, newtd);
279
280 thread_lock(newtd);
281 TD_SET_CAN_RUN(newtd);
282 sched_add(newtd, SRQ_BORING);
283
284 return (0);
285
286 fail:
287 #ifdef RACCT
288 if (racct_enable) {
289 PROC_LOCK(p);
290 racct_sub(p, RACCT_NTHR, 1);
291 PROC_UNLOCK(p);
292 }
293 #endif
294 return (error);
295 }
296
297 int
sys_thr_self(struct thread * td,struct thr_self_args * uap)298 sys_thr_self(struct thread *td, struct thr_self_args *uap)
299 /* long *id */
300 {
301 int error;
302
303 error = suword_lwpid(uap->id, (unsigned)td->td_tid);
304 if (error == -1)
305 return (EFAULT);
306 return (0);
307 }
308
309 int
sys_thr_exit(struct thread * td,struct thr_exit_args * uap)310 sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
311 /* long *state */
312 {
313
314 umtx_thread_exit(td);
315
316 /* Signal userland that it can free the stack. */
317 if ((void *)uap->state != NULL) {
318 (void)suword_lwpid(uap->state, 1);
319 (void)kern_umtx_wake(td, uap->state, INT_MAX, 0);
320 }
321
322 return (kern_thr_exit(td));
323 }
324
325 int
kern_thr_exit(struct thread * td)326 kern_thr_exit(struct thread *td)
327 {
328 struct proc *p;
329
330 p = td->td_proc;
331
332 /*
333 * If all of the threads in a process call this routine to
334 * exit (e.g. all threads call pthread_exit()), exactly one
335 * thread should return to the caller to terminate the process
336 * instead of the thread.
337 *
338 * Checking p_numthreads alone is not sufficient since threads
339 * might be committed to terminating while the PROC_LOCK is
340 * dropped in either ptracestop() or while removing this thread
341 * from the tidhash. Instead, the p_pendingexits field holds
342 * the count of threads in either of those states and a thread
343 * is considered the "last" thread if all of the other threads
344 * in a process are already terminating.
345 */
346 PROC_LOCK(p);
347 if (p->p_numthreads == p->p_pendingexits + 1) {
348 /*
349 * Ignore attempts to shut down last thread in the
350 * proc. This will actually call _exit(2) in the
351 * usermode trampoline when it returns.
352 */
353 PROC_UNLOCK(p);
354 return (0);
355 }
356
357 if (p->p_sysent->sv_ontdexit != NULL)
358 p->p_sysent->sv_ontdexit(td);
359
360 td->td_dbgflags |= TDB_EXIT;
361 if (p->p_ptevents & PTRACE_LWP) {
362 p->p_pendingexits++;
363 ptracestop(td, SIGTRAP, NULL);
364 p->p_pendingexits--;
365 }
366 tidhash_remove(td);
367
368 /*
369 * The check above should prevent all other threads from this
370 * process from exiting while the PROC_LOCK is dropped, so
371 * there must be at least one other thread other than the
372 * current thread.
373 */
374 KASSERT(p->p_numthreads > 1, ("too few threads"));
375 racct_sub(p, RACCT_NTHR, 1);
376 tdsigcleanup(td);
377
378 #ifdef AUDIT
379 AUDIT_SYSCALL_EXIT(0, td);
380 #endif
381
382 PROC_SLOCK(p);
383 thread_stopped(p);
384 thread_exit();
385 /* NOTREACHED */
386 }
387
388 int
sys_thr_kill(struct thread * td,struct thr_kill_args * uap)389 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
390 /* long id, int sig */
391 {
392 ksiginfo_t ksi;
393 struct thread *ttd;
394 struct proc *p;
395 int error;
396
397 p = td->td_proc;
398 ksiginfo_init(&ksi);
399 ksi.ksi_signo = uap->sig;
400 ksi.ksi_code = SI_LWP;
401 ksi.ksi_pid = p->p_pid;
402 ksi.ksi_uid = td->td_ucred->cr_ruid;
403 if (uap->id == -1) {
404 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
405 error = EINVAL;
406 } else {
407 error = ESRCH;
408 PROC_LOCK(p);
409 FOREACH_THREAD_IN_PROC(p, ttd) {
410 if (ttd != td) {
411 error = 0;
412 if (uap->sig == 0)
413 break;
414 tdksignal(ttd, uap->sig, &ksi);
415 }
416 }
417 PROC_UNLOCK(p);
418 }
419 } else {
420 error = 0;
421 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
422 if (ttd == NULL)
423 return (ESRCH);
424 if (uap->sig == 0)
425 ;
426 else if (!_SIG_VALID(uap->sig))
427 error = EINVAL;
428 else
429 tdksignal(ttd, uap->sig, &ksi);
430 PROC_UNLOCK(ttd->td_proc);
431 }
432 return (error);
433 }
434
435 int
sys_thr_kill2(struct thread * td,struct thr_kill2_args * uap)436 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
437 /* pid_t pid, long id, int sig */
438 {
439 ksiginfo_t ksi;
440 struct thread *ttd;
441 struct proc *p;
442 int error;
443
444 AUDIT_ARG_SIGNUM(uap->sig);
445
446 ksiginfo_init(&ksi);
447 ksi.ksi_signo = uap->sig;
448 ksi.ksi_code = SI_LWP;
449 ksi.ksi_pid = td->td_proc->p_pid;
450 ksi.ksi_uid = td->td_ucred->cr_ruid;
451 if (uap->id == -1) {
452 if ((p = pfind(uap->pid)) == NULL)
453 return (ESRCH);
454 AUDIT_ARG_PROCESS(p);
455 error = p_cansignal(td, p, uap->sig);
456 if (error) {
457 PROC_UNLOCK(p);
458 return (error);
459 }
460 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
461 error = EINVAL;
462 } else {
463 error = ESRCH;
464 FOREACH_THREAD_IN_PROC(p, ttd) {
465 if (ttd != td) {
466 error = 0;
467 if (uap->sig == 0)
468 break;
469 tdksignal(ttd, uap->sig, &ksi);
470 }
471 }
472 }
473 PROC_UNLOCK(p);
474 } else {
475 ttd = tdfind((lwpid_t)uap->id, uap->pid);
476 if (ttd == NULL)
477 return (ESRCH);
478 p = ttd->td_proc;
479 AUDIT_ARG_PROCESS(p);
480 error = p_cansignal(td, p, uap->sig);
481 if (uap->sig == 0)
482 ;
483 else if (!_SIG_VALID(uap->sig))
484 error = EINVAL;
485 else
486 tdksignal(ttd, uap->sig, &ksi);
487 PROC_UNLOCK(p);
488 }
489 return (error);
490 }
491
492 int
sys_thr_suspend(struct thread * td,struct thr_suspend_args * uap)493 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
494 /* const struct timespec *timeout */
495 {
496 struct timespec ts, *tsp;
497 int error;
498
499 tsp = NULL;
500 if (uap->timeout != NULL) {
501 error = umtx_copyin_timeout(uap->timeout, &ts);
502 if (error != 0)
503 return (error);
504 tsp = &ts;
505 }
506
507 return (kern_thr_suspend(td, tsp));
508 }
509
510 int
kern_thr_suspend(struct thread * td,struct timespec * tsp)511 kern_thr_suspend(struct thread *td, struct timespec *tsp)
512 {
513 struct proc *p = td->td_proc;
514 struct timeval tv;
515 int error = 0;
516 int timo = 0;
517
518 if (td->td_pflags & TDP_WAKEUP) {
519 td->td_pflags &= ~TDP_WAKEUP;
520 return (0);
521 }
522
523 if (tsp != NULL) {
524 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
525 error = EWOULDBLOCK;
526 else {
527 TIMESPEC_TO_TIMEVAL(&tv, tsp);
528 timo = tvtohz(&tv);
529 }
530 }
531
532 PROC_LOCK(p);
533 if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
534 error = msleep((void *)td, &p->p_mtx,
535 PCATCH, "lthr", timo);
536
537 if (td->td_flags & TDF_THRWAKEUP) {
538 thread_lock(td);
539 td->td_flags &= ~TDF_THRWAKEUP;
540 thread_unlock(td);
541 PROC_UNLOCK(p);
542 return (0);
543 }
544 PROC_UNLOCK(p);
545 if (error == EWOULDBLOCK)
546 error = ETIMEDOUT;
547 else if (error == ERESTART) {
548 if (timo != 0)
549 error = EINTR;
550 }
551 return (error);
552 }
553
554 int
sys_thr_wake(struct thread * td,struct thr_wake_args * uap)555 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
556 /* long id */
557 {
558 struct proc *p;
559 struct thread *ttd;
560
561 if (uap->id == td->td_tid) {
562 td->td_pflags |= TDP_WAKEUP;
563 return (0);
564 }
565
566 p = td->td_proc;
567 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
568 if (ttd == NULL)
569 return (ESRCH);
570 thread_lock(ttd);
571 ttd->td_flags |= TDF_THRWAKEUP;
572 thread_unlock(ttd);
573 wakeup((void *)ttd);
574 PROC_UNLOCK(p);
575 return (0);
576 }
577
578 int
sys_thr_set_name(struct thread * td,struct thr_set_name_args * uap)579 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
580 {
581 struct proc *p;
582 char name[MAXCOMLEN + 1];
583 struct thread *ttd;
584 int error;
585
586 error = 0;
587 name[0] = '\0';
588 if (uap->name != NULL) {
589 error = copyinstr(uap->name, name, sizeof(name), NULL);
590 if (error == ENAMETOOLONG) {
591 error = copyin(uap->name, name, sizeof(name) - 1);
592 name[sizeof(name) - 1] = '\0';
593 }
594 if (error)
595 return (error);
596 }
597 p = td->td_proc;
598 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
599 if (ttd == NULL)
600 return (ESRCH);
601 strcpy(ttd->td_name, name);
602 #ifdef HWPMC_HOOKS
603 if (PMC_PROC_IS_USING_PMCS(p) || PMC_SYSTEM_SAMPLING_ACTIVE())
604 PMC_CALL_HOOK_UNLOCKED(ttd, PMC_FN_THR_CREATE_LOG, NULL);
605 #endif
606 #ifdef KTR
607 sched_clear_tdname(ttd);
608 #endif
609 PROC_UNLOCK(p);
610 return (error);
611 }
612
613 int
kern_thr_alloc(struct proc * p,int pages,struct thread ** ntd)614 kern_thr_alloc(struct proc *p, int pages, struct thread **ntd)
615 {
616
617 /* Have race condition but it is cheap. */
618 if (p->p_numthreads >= max_threads_per_proc) {
619 ++max_threads_hits;
620 return (EPROCLIM);
621 }
622
623 *ntd = thread_alloc(pages);
624 if (*ntd == NULL)
625 return (ENOMEM);
626
627 return (0);
628 }
629