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 "opt_posix.h"
30 #include "opt_hwpmc_hooks.h"
31
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/limits.h>
35 #include <sys/lock.h>
36 #include <sys/mutex.h>
37 #include <sys/priv.h>
38 #include <sys/proc.h>
39 #include <sys/posix4.h>
40 #include <sys/ptrace.h>
41 #include <sys/racct.h>
42 #include <sys/resourcevar.h>
43 #include <sys/rtprio.h>
44 #include <sys/rwlock.h>
45 #include <sys/sched.h>
46 #include <sys/sysctl.h>
47 #include <sys/smp.h>
48 #include <sys/syscallsubr.h>
49 #include <sys/sysent.h>
50 #include <sys/sysproto.h>
51 #include <sys/signalvar.h>
52 #include <sys/sysctl.h>
53 #include <sys/thr.h>
54 #include <sys/ucontext.h>
55 #include <sys/umtxvar.h>
56 #ifdef HWPMC_HOOKS
57 #include <sys/pmckern.h>
58 #endif
59
60 #include <machine/frame.h>
61
62 #include <security/audit/audit.h>
63
64 static SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
65 "thread allocation");
66
67 int max_threads_per_proc = 1500;
68 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
69 &max_threads_per_proc, 0, "Limit on threads per proc");
70
71 static int max_threads_hits;
72 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
73 &max_threads_hits, 0, "kern.threads.max_threads_per_proc hit count");
74
75 #ifdef COMPAT_FREEBSD32
76
77 static inline int
suword_lwpid(void * addr,lwpid_t lwpid)78 suword_lwpid(void *addr, lwpid_t lwpid)
79 {
80 int error;
81
82 if (SV_CURPROC_FLAG(SV_LP64))
83 error = suword(addr, lwpid);
84 else
85 error = suword32(addr, lwpid);
86 return (error);
87 }
88
89 #else
90 #define suword_lwpid suword
91 #endif
92
93 /*
94 * System call interface.
95 */
96
97 struct thr_create_initthr_args {
98 ucontext_t ctx;
99 long *tid;
100 };
101
102 static int
thr_create_initthr(struct thread * td,void * thunk)103 thr_create_initthr(struct thread *td, void *thunk)
104 {
105 struct thr_create_initthr_args *args;
106
107 /* Copy out the child tid. */
108 args = thunk;
109 if (args->tid != NULL && suword_lwpid(args->tid, td->td_tid))
110 return (EFAULT);
111
112 return (set_mcontext(td, &args->ctx.uc_mcontext));
113 }
114
115 int
sys_thr_create(struct thread * td,struct thr_create_args * uap)116 sys_thr_create(struct thread *td, struct thr_create_args *uap)
117 /* ucontext_t *ctx, long *id, int flags */
118 {
119 struct thr_create_initthr_args args;
120 int error;
121
122 if ((error = copyin(uap->ctx, &args.ctx, sizeof(args.ctx))))
123 return (error);
124 args.tid = uap->id;
125 return (thread_create(td, NULL, thr_create_initthr, &args));
126 }
127
128 int
sys_thr_new(struct thread * td,struct thr_new_args * uap)129 sys_thr_new(struct thread *td, struct thr_new_args *uap)
130 /* struct thr_param * */
131 {
132 struct thr_param param;
133 int error;
134
135 if (uap->param_size < 0 || uap->param_size > sizeof(param))
136 return (EINVAL);
137 bzero(¶m, sizeof(param));
138 if ((error = copyin(uap->param, ¶m, uap->param_size)))
139 return (error);
140 return (kern_thr_new(td, ¶m));
141 }
142
143 static int
thr_new_initthr(struct thread * td,void * thunk)144 thr_new_initthr(struct thread *td, void *thunk)
145 {
146 stack_t stack;
147 struct thr_param *param;
148 int error;
149
150 /*
151 * Here we copy out tid to two places, one for child and one
152 * for parent, because pthread can create a detached thread,
153 * if parent wants to safely access child tid, it has to provide
154 * its storage, because child thread may exit quickly and
155 * memory is freed before parent thread can access it.
156 */
157 param = thunk;
158 if ((param->child_tid != NULL &&
159 suword_lwpid(param->child_tid, td->td_tid)) ||
160 (param->parent_tid != NULL &&
161 suword_lwpid(param->parent_tid, td->td_tid)))
162 return (EFAULT);
163
164 /* Set up our machine context. */
165 stack.ss_sp = param->stack_base;
166 stack.ss_size = param->stack_size;
167 /* Set upcall address to user thread entry function. */
168 error = cpu_set_upcall(td, param->start_func, param->arg, &stack);
169 if (error != 0)
170 return (error);
171 /* Setup user TLS address and TLS pointer register. */
172 return (cpu_set_user_tls(td, param->tls_base));
173 }
174
175 int
kern_thr_new(struct thread * td,struct thr_param * param)176 kern_thr_new(struct thread *td, struct thr_param *param)
177 {
178 struct rtprio rtp, *rtpp;
179 int error;
180
181 rtpp = NULL;
182 if (param->rtp != 0) {
183 error = copyin(param->rtp, &rtp, sizeof(struct rtprio));
184 if (error)
185 return (error);
186 rtpp = &rtp;
187 }
188 return (thread_create(td, rtpp, thr_new_initthr, param));
189 }
190
191 int
thread_create(struct thread * td,struct rtprio * rtp,int (* initialize_thread)(struct thread *,void *),void * thunk)192 thread_create(struct thread *td, struct rtprio *rtp,
193 int (*initialize_thread)(struct thread *, void *), void *thunk)
194 {
195 struct thread *newtd;
196 struct proc *p;
197 int error;
198
199 p = td->td_proc;
200
201 if (rtp != NULL) {
202 switch(rtp->type) {
203 case RTP_PRIO_REALTIME:
204 case RTP_PRIO_FIFO:
205 /* Only root can set scheduler policy */
206 if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0)
207 return (EPERM);
208 if (rtp->prio > RTP_PRIO_MAX)
209 return (EINVAL);
210 break;
211 case RTP_PRIO_NORMAL:
212 rtp->prio = 0;
213 break;
214 default:
215 return (EINVAL);
216 }
217 }
218
219 #ifdef RACCT
220 if (racct_enable) {
221 PROC_LOCK(p);
222 error = racct_add(p, RACCT_NTHR, 1);
223 PROC_UNLOCK(p);
224 if (error != 0)
225 return (EPROCLIM);
226 }
227 #endif
228
229 /* Initialize our td */
230 error = kern_thr_alloc(p, 0, &newtd);
231 if (error)
232 goto fail;
233
234 bzero(&newtd->td_startzero,
235 __rangeof(struct thread, td_startzero, td_endzero));
236 bcopy(&td->td_startcopy, &newtd->td_startcopy,
237 __rangeof(struct thread, td_startcopy, td_endcopy));
238 newtd->td_proc = td->td_proc;
239 newtd->td_rb_list = newtd->td_rbp_list = newtd->td_rb_inact = 0;
240 thread_cow_get(newtd, td);
241
242 cpu_copy_thread(newtd, td);
243
244 error = initialize_thread(newtd, thunk);
245 if (error != 0) {
246 thread_cow_free(newtd);
247 thread_free(newtd);
248 goto fail;
249 }
250
251 PROC_LOCK(p);
252 p->p_flag |= P_HADTHREADS;
253 thread_link(newtd, p);
254 bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
255 thread_lock(td);
256 /* let the scheduler know about these things. */
257 sched_fork_thread(td, newtd);
258 thread_unlock(td);
259 if (P_SHOULDSTOP(p))
260 ast_sched(newtd, TDA_SUSPEND);
261 if (p->p_ptevents & PTRACE_LWP)
262 newtd->td_dbgflags |= TDB_BORN;
263
264 PROC_UNLOCK(p);
265 #ifdef HWPMC_HOOKS
266 if (PMC_PROC_IS_USING_PMCS(p))
267 PMC_CALL_HOOK(newtd, PMC_FN_THR_CREATE, NULL);
268 else if (PMC_SYSTEM_SAMPLING_ACTIVE())
269 PMC_CALL_HOOK_UNLOCKED(newtd, PMC_FN_THR_CREATE_LOG, NULL);
270 #endif
271
272 tidhash_add(newtd);
273
274 /* ignore timesharing class */
275 if (rtp != NULL && !(td->td_pri_class == PRI_TIMESHARE &&
276 rtp->type == RTP_PRIO_NORMAL))
277 rtp_to_pri(rtp, newtd);
278
279 thread_lock(newtd);
280 TD_SET_CAN_RUN(newtd);
281 sched_add(newtd, SRQ_BORING);
282
283 return (0);
284
285 fail:
286 #ifdef RACCT
287 if (racct_enable) {
288 PROC_LOCK(p);
289 racct_sub(p, RACCT_NTHR, 1);
290 PROC_UNLOCK(p);
291 }
292 #endif
293 return (error);
294 }
295
296 int
sys_thr_self(struct thread * td,struct thr_self_args * uap)297 sys_thr_self(struct thread *td, struct thr_self_args *uap)
298 /* long *id */
299 {
300 int error;
301
302 error = suword_lwpid(uap->id, (unsigned)td->td_tid);
303 if (error == -1)
304 return (EFAULT);
305 return (0);
306 }
307
308 int
sys_thr_exit(struct thread * td,struct thr_exit_args * uap)309 sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
310 /* long *state */
311 {
312
313 umtx_thread_exit(td);
314
315 /* Signal userland that it can free the stack. */
316 if ((void *)uap->state != NULL) {
317 (void)suword_lwpid(uap->state, 1);
318 (void)kern_umtx_wake(td, uap->state, INT_MAX, 0);
319 }
320
321 return (kern_thr_exit(td));
322 }
323
324 int
kern_thr_exit(struct thread * td)325 kern_thr_exit(struct thread *td)
326 {
327 struct proc *p;
328
329 p = td->td_proc;
330
331 /*
332 * If all of the threads in a process call this routine to
333 * exit (e.g. all threads call pthread_exit()), exactly one
334 * thread should return to the caller to terminate the process
335 * instead of the thread.
336 *
337 * Checking p_numthreads alone is not sufficient since threads
338 * might be committed to terminating while the PROC_LOCK is
339 * dropped in either ptracestop() or while removing this thread
340 * from the tidhash. Instead, the p_pendingexits field holds
341 * the count of threads in either of those states and a thread
342 * is considered the "last" thread if all of the other threads
343 * in a process are already terminating.
344 */
345 PROC_LOCK(p);
346 if (p->p_numthreads == p->p_pendingexits + 1) {
347 /*
348 * Ignore attempts to shut down last thread in the
349 * proc. This will actually call _exit(2) in the
350 * usermode trampoline when it returns.
351 */
352 PROC_UNLOCK(p);
353 return (0);
354 }
355
356 if (p->p_sysent->sv_ontdexit != NULL)
357 p->p_sysent->sv_ontdexit(td);
358
359 td->td_dbgflags |= TDB_EXIT;
360 if (p->p_ptevents & PTRACE_LWP) {
361 p->p_pendingexits++;
362 ptracestop(td, SIGTRAP, NULL);
363 p->p_pendingexits--;
364 }
365 tidhash_remove(td);
366
367 /*
368 * The check above should prevent all other threads from this
369 * process from exiting while the PROC_LOCK is dropped, so
370 * there must be at least one other thread other than the
371 * current thread.
372 */
373 KASSERT(p->p_numthreads > 1, ("too few threads"));
374 racct_sub(p, RACCT_NTHR, 1);
375 tdsigcleanup(td);
376
377 #ifdef AUDIT
378 AUDIT_SYSCALL_EXIT(0, td);
379 #endif
380
381 PROC_SLOCK(p);
382 thread_stopped(p);
383 thread_exit();
384 /* NOTREACHED */
385 }
386
387 int
sys_thr_kill(struct thread * td,struct thr_kill_args * uap)388 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
389 /* long id, int sig */
390 {
391 ksiginfo_t ksi;
392 struct thread *ttd;
393 struct proc *p;
394 int error;
395
396 p = td->td_proc;
397 ksiginfo_init(&ksi);
398 ksi.ksi_signo = uap->sig;
399 ksi.ksi_code = SI_LWP;
400 ksi.ksi_pid = p->p_pid;
401 ksi.ksi_uid = td->td_ucred->cr_ruid;
402 if (uap->id == -1) {
403 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
404 error = EINVAL;
405 } else {
406 error = ESRCH;
407 PROC_LOCK(p);
408 FOREACH_THREAD_IN_PROC(p, ttd) {
409 if (ttd != td) {
410 error = 0;
411 if (uap->sig == 0)
412 break;
413 tdksignal(ttd, uap->sig, &ksi);
414 }
415 }
416 PROC_UNLOCK(p);
417 }
418 } else {
419 error = 0;
420 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
421 if (ttd == NULL)
422 return (ESRCH);
423 if (uap->sig == 0)
424 ;
425 else if (!_SIG_VALID(uap->sig))
426 error = EINVAL;
427 else
428 tdksignal(ttd, uap->sig, &ksi);
429 PROC_UNLOCK(ttd->td_proc);
430 }
431 return (error);
432 }
433
434 int
sys_thr_kill2(struct thread * td,struct thr_kill2_args * uap)435 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
436 /* pid_t pid, long id, int sig */
437 {
438 ksiginfo_t ksi;
439 struct thread *ttd;
440 struct proc *p;
441 int error;
442
443 AUDIT_ARG_SIGNUM(uap->sig);
444
445 ksiginfo_init(&ksi);
446 ksi.ksi_signo = uap->sig;
447 ksi.ksi_code = SI_LWP;
448 ksi.ksi_pid = td->td_proc->p_pid;
449 ksi.ksi_uid = td->td_ucred->cr_ruid;
450 if (uap->id == -1) {
451 if ((p = pfind(uap->pid)) == NULL)
452 return (ESRCH);
453 AUDIT_ARG_PROCESS(p);
454 error = p_cansignal(td, p, uap->sig);
455 if (error) {
456 PROC_UNLOCK(p);
457 return (error);
458 }
459 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
460 error = EINVAL;
461 } else {
462 error = ESRCH;
463 FOREACH_THREAD_IN_PROC(p, ttd) {
464 if (ttd != td) {
465 error = 0;
466 if (uap->sig == 0)
467 break;
468 tdksignal(ttd, uap->sig, &ksi);
469 }
470 }
471 }
472 PROC_UNLOCK(p);
473 } else {
474 ttd = tdfind((lwpid_t)uap->id, uap->pid);
475 if (ttd == NULL)
476 return (ESRCH);
477 p = ttd->td_proc;
478 AUDIT_ARG_PROCESS(p);
479 error = p_cansignal(td, p, uap->sig);
480 if (uap->sig == 0)
481 ;
482 else if (!_SIG_VALID(uap->sig))
483 error = EINVAL;
484 else
485 tdksignal(ttd, uap->sig, &ksi);
486 PROC_UNLOCK(p);
487 }
488 return (error);
489 }
490
491 int
sys_thr_suspend(struct thread * td,struct thr_suspend_args * uap)492 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
493 /* const struct timespec *timeout */
494 {
495 struct timespec ts, *tsp;
496 int error;
497
498 tsp = NULL;
499 if (uap->timeout != NULL) {
500 error = umtx_copyin_timeout(uap->timeout, &ts);
501 if (error != 0)
502 return (error);
503 tsp = &ts;
504 }
505
506 return (kern_thr_suspend(td, tsp));
507 }
508
509 int
kern_thr_suspend(struct thread * td,struct timespec * tsp)510 kern_thr_suspend(struct thread *td, struct timespec *tsp)
511 {
512 struct proc *p = td->td_proc;
513 struct timeval tv;
514 int error = 0;
515 int timo = 0;
516
517 if (td->td_pflags & TDP_WAKEUP) {
518 td->td_pflags &= ~TDP_WAKEUP;
519 return (0);
520 }
521
522 if (tsp != NULL) {
523 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
524 error = EWOULDBLOCK;
525 else {
526 TIMESPEC_TO_TIMEVAL(&tv, tsp);
527 timo = tvtohz(&tv);
528 }
529 }
530
531 PROC_LOCK(p);
532 if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
533 error = msleep((void *)td, &p->p_mtx,
534 PCATCH, "lthr", timo);
535
536 if (td->td_flags & TDF_THRWAKEUP) {
537 thread_lock(td);
538 td->td_flags &= ~TDF_THRWAKEUP;
539 thread_unlock(td);
540 PROC_UNLOCK(p);
541 return (0);
542 }
543 PROC_UNLOCK(p);
544 if (error == EWOULDBLOCK)
545 error = ETIMEDOUT;
546 else if (error == ERESTART) {
547 if (timo != 0)
548 error = EINTR;
549 }
550 return (error);
551 }
552
553 int
sys_thr_wake(struct thread * td,struct thr_wake_args * uap)554 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
555 /* long id */
556 {
557 struct proc *p;
558 struct thread *ttd;
559
560 if (uap->id == td->td_tid) {
561 td->td_pflags |= TDP_WAKEUP;
562 return (0);
563 }
564
565 p = td->td_proc;
566 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
567 if (ttd == NULL)
568 return (ESRCH);
569 thread_lock(ttd);
570 ttd->td_flags |= TDF_THRWAKEUP;
571 thread_unlock(ttd);
572 wakeup((void *)ttd);
573 PROC_UNLOCK(p);
574 return (0);
575 }
576
577 int
sys_thr_set_name(struct thread * td,struct thr_set_name_args * uap)578 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
579 {
580 struct proc *p;
581 char name[MAXCOMLEN + 1];
582 struct thread *ttd;
583 int error;
584
585 error = 0;
586 name[0] = '\0';
587 if (uap->name != NULL) {
588 error = copyinstr(uap->name, name, sizeof(name), NULL);
589 if (error == ENAMETOOLONG) {
590 error = copyin(uap->name, name, sizeof(name) - 1);
591 name[sizeof(name) - 1] = '\0';
592 }
593 if (error)
594 return (error);
595 }
596 p = td->td_proc;
597 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
598 if (ttd == NULL)
599 return (ESRCH);
600 strcpy(ttd->td_name, name);
601 #ifdef HWPMC_HOOKS
602 if (PMC_PROC_IS_USING_PMCS(p) || PMC_SYSTEM_SAMPLING_ACTIVE())
603 PMC_CALL_HOOK_UNLOCKED(ttd, PMC_FN_THR_CREATE_LOG, NULL);
604 #endif
605 #ifdef KTR
606 sched_clear_tdname(ttd);
607 #endif
608 PROC_UNLOCK(p);
609 return (error);
610 }
611
612 int
kern_thr_alloc(struct proc * p,int pages,struct thread ** ntd)613 kern_thr_alloc(struct proc *p, int pages, struct thread **ntd)
614 {
615
616 /* Have race condition but it is cheap. */
617 if (p->p_numthreads >= max_threads_per_proc) {
618 ++max_threads_hits;
619 return (EPROCLIM);
620 }
621
622 *ntd = thread_alloc(pages);
623 if (*ntd == NULL)
624 return (ENOMEM);
625
626 return (0);
627 }
628