xref: /freebsd/sys/kern/kern_thr.c (revision bb15ca603fa442c72dde3f3cb8b46db6970e3950)
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("$FreeBSD$");
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/racct.h>
40 #include <sys/resourcevar.h>
41 #include <sys/rwlock.h>
42 #include <sys/sched.h>
43 #include <sys/sysctl.h>
44 #include <sys/smp.h>
45 #include <sys/syscallsubr.h>
46 #include <sys/sysent.h>
47 #include <sys/systm.h>
48 #include <sys/sysproto.h>
49 #include <sys/signalvar.h>
50 #include <sys/sysctl.h>
51 #include <sys/ucontext.h>
52 #include <sys/thr.h>
53 #include <sys/rtprio.h>
54 #include <sys/umtx.h>
55 #include <sys/limits.h>
56 
57 #include <machine/frame.h>
58 
59 #include <security/audit/audit.h>
60 
61 static SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0,
62     "thread allocation");
63 
64 static int max_threads_per_proc = 1500;
65 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
66     &max_threads_per_proc, 0, "Limit on threads per proc");
67 
68 static int max_threads_hits;
69 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
70     &max_threads_hits, 0, "kern.threads.max_threads_per_proc hit count");
71 
72 #ifdef COMPAT_FREEBSD32
73 
74 static inline int
75 suword_lwpid(void *addr, lwpid_t lwpid)
76 {
77 	int error;
78 
79 	if (SV_CURPROC_FLAG(SV_LP64))
80 		error = suword(addr, lwpid);
81 	else
82 		error = suword32(addr, lwpid);
83 	return (error);
84 }
85 
86 #else
87 #define suword_lwpid	suword
88 #endif
89 
90 static int create_thread(struct thread *td, mcontext_t *ctx,
91 			 void (*start_func)(void *), void *arg,
92 			 char *stack_base, size_t stack_size,
93 			 char *tls_base,
94 			 long *child_tid, long *parent_tid,
95 			 int flags, struct rtprio *rtp);
96 
97 /*
98  * System call interface.
99  */
100 int
101 sys_thr_create(struct thread *td, struct thr_create_args *uap)
102     /* ucontext_t *ctx, long *id, int flags */
103 {
104 	ucontext_t ctx;
105 	int error;
106 
107 	if ((error = copyin(uap->ctx, &ctx, sizeof(ctx))))
108 		return (error);
109 
110 	error = create_thread(td, &ctx.uc_mcontext, NULL, NULL,
111 		NULL, 0, NULL, uap->id, NULL, uap->flags, NULL);
112 	return (error);
113 }
114 
115 int
116 sys_thr_new(struct thread *td, struct thr_new_args *uap)
117     /* struct thr_param * */
118 {
119 	struct thr_param param;
120 	int error;
121 
122 	if (uap->param_size < 0 || uap->param_size > sizeof(param))
123 		return (EINVAL);
124 	bzero(&param, sizeof(param));
125 	if ((error = copyin(uap->param, &param, uap->param_size)))
126 		return (error);
127 	return (kern_thr_new(td, &param));
128 }
129 
130 int
131 kern_thr_new(struct thread *td, struct thr_param *param)
132 {
133 	struct rtprio rtp, *rtpp;
134 	int error;
135 
136 	rtpp = NULL;
137 	if (param->rtp != 0) {
138 		error = copyin(param->rtp, &rtp, sizeof(struct rtprio));
139 		if (error)
140 			return (error);
141 		rtpp = &rtp;
142 	}
143 	error = create_thread(td, NULL, param->start_func, param->arg,
144 		param->stack_base, param->stack_size, param->tls_base,
145 		param->child_tid, param->parent_tid, param->flags,
146 		rtpp);
147 	return (error);
148 }
149 
150 static int
151 create_thread(struct thread *td, mcontext_t *ctx,
152 	    void (*start_func)(void *), void *arg,
153 	    char *stack_base, size_t stack_size,
154 	    char *tls_base,
155 	    long *child_tid, long *parent_tid,
156 	    int flags, struct rtprio *rtp)
157 {
158 	stack_t stack;
159 	struct thread *newtd;
160 	struct proc *p;
161 	int error;
162 
163 	p = td->td_proc;
164 
165 	/* Have race condition but it is cheap. */
166 	if (p->p_numthreads >= max_threads_per_proc) {
167 		++max_threads_hits;
168 		return (EPROCLIM);
169 	}
170 
171 	if (rtp != NULL) {
172 		switch(rtp->type) {
173 		case RTP_PRIO_REALTIME:
174 		case RTP_PRIO_FIFO:
175 			/* Only root can set scheduler policy */
176 			if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0)
177 				return (EPERM);
178 			if (rtp->prio > RTP_PRIO_MAX)
179 				return (EINVAL);
180 			break;
181 		case RTP_PRIO_NORMAL:
182 			rtp->prio = 0;
183 			break;
184 		default:
185 			return (EINVAL);
186 		}
187 	}
188 
189 #ifdef RACCT
190 	PROC_LOCK(td->td_proc);
191 	error = racct_add(p, RACCT_NTHR, 1);
192 	PROC_UNLOCK(td->td_proc);
193 	if (error != 0)
194 		return (EPROCLIM);
195 #endif
196 
197 	/* Initialize our td */
198 	newtd = thread_alloc(0);
199 	if (newtd == NULL) {
200 		error = ENOMEM;
201 		goto fail;
202 	}
203 
204 	cpu_set_upcall(newtd, td);
205 
206 	/*
207 	 * Try the copyout as soon as we allocate the td so we don't
208 	 * have to tear things down in a failure case below.
209 	 * Here we copy out tid to two places, one for child and one
210 	 * for parent, because pthread can create a detached thread,
211 	 * if parent wants to safely access child tid, it has to provide
212 	 * its storage, because child thread may exit quickly and
213 	 * memory is freed before parent thread can access it.
214 	 */
215 	if ((child_tid != NULL &&
216 	    suword_lwpid(child_tid, newtd->td_tid)) ||
217 	    (parent_tid != NULL &&
218 	    suword_lwpid(parent_tid, newtd->td_tid))) {
219 		thread_free(newtd);
220 		error = EFAULT;
221 		goto fail;
222 	}
223 
224 	bzero(&newtd->td_startzero,
225 	    __rangeof(struct thread, td_startzero, td_endzero));
226 	bcopy(&td->td_startcopy, &newtd->td_startcopy,
227 	    __rangeof(struct thread, td_startcopy, td_endcopy));
228 	newtd->td_proc = td->td_proc;
229 	newtd->td_ucred = crhold(td->td_ucred);
230 
231 	if (ctx != NULL) { /* old way to set user context */
232 		error = set_mcontext(newtd, ctx);
233 		if (error != 0) {
234 			thread_free(newtd);
235 			crfree(td->td_ucred);
236 			goto fail;
237 		}
238 	} else {
239 		/* Set up our machine context. */
240 		stack.ss_sp = stack_base;
241 		stack.ss_size = stack_size;
242 		/* Set upcall address to user thread entry function. */
243 		cpu_set_upcall_kse(newtd, start_func, arg, &stack);
244 		/* Setup user TLS address and TLS pointer register. */
245 		error = cpu_set_user_tls(newtd, tls_base);
246 		if (error != 0) {
247 			thread_free(newtd);
248 			crfree(td->td_ucred);
249 			goto fail;
250 		}
251 	}
252 
253 	PROC_LOCK(td->td_proc);
254 	td->td_proc->p_flag |= P_HADTHREADS;
255 	newtd->td_sigmask = td->td_sigmask;
256 	thread_link(newtd, p);
257 	bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
258 	thread_lock(td);
259 	/* let the scheduler know about these things. */
260 	sched_fork_thread(td, newtd);
261 	thread_unlock(td);
262 	if (P_SHOULDSTOP(p))
263 		newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
264 	PROC_UNLOCK(p);
265 
266 	tidhash_add(newtd);
267 
268 	thread_lock(newtd);
269 	if (rtp != NULL) {
270 		if (!(td->td_pri_class == PRI_TIMESHARE &&
271 		      rtp->type == RTP_PRIO_NORMAL)) {
272 			rtp_to_pri(rtp, newtd);
273 			sched_prio(newtd, newtd->td_user_pri);
274 		} /* ignore timesharing class */
275 	}
276 	TD_SET_CAN_RUN(newtd);
277 	sched_add(newtd, SRQ_BORING);
278 	thread_unlock(newtd);
279 
280 	return (0);
281 
282 fail:
283 #ifdef RACCT
284 	PROC_LOCK(p);
285 	racct_sub(p, RACCT_NTHR, 1);
286 	PROC_UNLOCK(p);
287 #endif
288 	return (error);
289 }
290 
291 int
292 sys_thr_self(struct thread *td, struct thr_self_args *uap)
293     /* long *id */
294 {
295 	int error;
296 
297 	error = suword_lwpid(uap->id, (unsigned)td->td_tid);
298 	if (error == -1)
299 		return (EFAULT);
300 	return (0);
301 }
302 
303 int
304 sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
305     /* long *state */
306 {
307 	struct proc *p;
308 
309 	p = td->td_proc;
310 
311 	/* Signal userland that it can free the stack. */
312 	if ((void *)uap->state != NULL) {
313 		suword_lwpid(uap->state, 1);
314 		kern_umtx_wake(td, uap->state, INT_MAX, 0);
315 	}
316 
317 	rw_wlock(&tidhash_lock);
318 
319 	PROC_LOCK(p);
320 	racct_sub(p, RACCT_NTHR, 1);
321 
322 	/*
323 	 * Shutting down last thread in the proc.  This will actually
324 	 * call exit() in the trampoline when it returns.
325 	 */
326 	if (p->p_numthreads != 1) {
327 		LIST_REMOVE(td, td_hash);
328 		rw_wunlock(&tidhash_lock);
329 		tdsigcleanup(td);
330 		PROC_SLOCK(p);
331 		thread_stopped(p);
332 		thread_exit();
333 		/* NOTREACHED */
334 	}
335 	PROC_UNLOCK(p);
336 	rw_wunlock(&tidhash_lock);
337 	return (0);
338 }
339 
340 int
341 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
342     /* long id, int sig */
343 {
344 	ksiginfo_t ksi;
345 	struct thread *ttd;
346 	struct proc *p;
347 	int error;
348 
349 	p = td->td_proc;
350 	ksiginfo_init(&ksi);
351 	ksi.ksi_signo = uap->sig;
352 	ksi.ksi_code = SI_LWP;
353 	ksi.ksi_pid = p->p_pid;
354 	ksi.ksi_uid = td->td_ucred->cr_ruid;
355 	if (uap->id == -1) {
356 		if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
357 			error = EINVAL;
358 		} else {
359 			error = ESRCH;
360 			PROC_LOCK(p);
361 			FOREACH_THREAD_IN_PROC(p, ttd) {
362 				if (ttd != td) {
363 					error = 0;
364 					if (uap->sig == 0)
365 						break;
366 					tdksignal(ttd, uap->sig, &ksi);
367 				}
368 			}
369 			PROC_UNLOCK(p);
370 		}
371 	} else {
372 		error = 0;
373 		ttd = tdfind((lwpid_t)uap->id, p->p_pid);
374 		if (ttd == NULL)
375 			return (ESRCH);
376 		if (uap->sig == 0)
377 			;
378 		else if (!_SIG_VALID(uap->sig))
379 			error = EINVAL;
380 		else
381 			tdksignal(ttd, uap->sig, &ksi);
382 		PROC_UNLOCK(ttd->td_proc);
383 	}
384 	return (error);
385 }
386 
387 int
388 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
389     /* pid_t pid, long id, int sig */
390 {
391 	ksiginfo_t ksi;
392 	struct thread *ttd;
393 	struct proc *p;
394 	int error;
395 
396 	AUDIT_ARG_SIGNUM(uap->sig);
397 
398 	ksiginfo_init(&ksi);
399 	ksi.ksi_signo = uap->sig;
400 	ksi.ksi_code = SI_LWP;
401 	ksi.ksi_pid = td->td_proc->p_pid;
402 	ksi.ksi_uid = td->td_ucred->cr_ruid;
403 	if (uap->id == -1) {
404 		if ((p = pfind(uap->pid)) == NULL)
405 			return (ESRCH);
406 		AUDIT_ARG_PROCESS(p);
407 		error = p_cansignal(td, p, uap->sig);
408 		if (error) {
409 			PROC_UNLOCK(p);
410 			return (error);
411 		}
412 		if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
413 			error = EINVAL;
414 		} else {
415 			error = ESRCH;
416 			FOREACH_THREAD_IN_PROC(p, ttd) {
417 				if (ttd != td) {
418 					error = 0;
419 					if (uap->sig == 0)
420 						break;
421 					tdksignal(ttd, uap->sig, &ksi);
422 				}
423 			}
424 		}
425 		PROC_UNLOCK(p);
426 	} else {
427 		ttd = tdfind((lwpid_t)uap->id, uap->pid);
428 		if (ttd == NULL)
429 			return (ESRCH);
430 		p = ttd->td_proc;
431 		AUDIT_ARG_PROCESS(p);
432 		error = p_cansignal(td, p, uap->sig);
433 		if (uap->sig == 0)
434 			;
435 		else if (!_SIG_VALID(uap->sig))
436 			error = EINVAL;
437 		else
438 			tdksignal(ttd, uap->sig, &ksi);
439 		PROC_UNLOCK(p);
440 	}
441 	return (error);
442 }
443 
444 int
445 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
446 	/* const struct timespec *timeout */
447 {
448 	struct timespec ts, *tsp;
449 	int error;
450 
451 	tsp = NULL;
452 	if (uap->timeout != NULL) {
453 		error = umtx_copyin_timeout(uap->timeout, &ts);
454 		if (error != 0)
455 			return (error);
456 		tsp = &ts;
457 	}
458 
459 	return (kern_thr_suspend(td, tsp));
460 }
461 
462 int
463 kern_thr_suspend(struct thread *td, struct timespec *tsp)
464 {
465 	struct proc *p = td->td_proc;
466 	struct timeval tv;
467 	int error = 0;
468 	int timo = 0;
469 
470 	if (td->td_pflags & TDP_WAKEUP) {
471 		td->td_pflags &= ~TDP_WAKEUP;
472 		return (0);
473 	}
474 
475 	if (tsp != NULL) {
476 		if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
477 			error = EWOULDBLOCK;
478 		else {
479 			TIMESPEC_TO_TIMEVAL(&tv, tsp);
480 			timo = tvtohz(&tv);
481 		}
482 	}
483 
484 	PROC_LOCK(p);
485 	if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
486 		error = msleep((void *)td, &p->p_mtx,
487 			 PCATCH, "lthr", timo);
488 
489 	if (td->td_flags & TDF_THRWAKEUP) {
490 		thread_lock(td);
491 		td->td_flags &= ~TDF_THRWAKEUP;
492 		thread_unlock(td);
493 		PROC_UNLOCK(p);
494 		return (0);
495 	}
496 	PROC_UNLOCK(p);
497 	if (error == EWOULDBLOCK)
498 		error = ETIMEDOUT;
499 	else if (error == ERESTART) {
500 		if (timo != 0)
501 			error = EINTR;
502 	}
503 	return (error);
504 }
505 
506 int
507 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
508 	/* long id */
509 {
510 	struct proc *p;
511 	struct thread *ttd;
512 
513 	if (uap->id == td->td_tid) {
514 		td->td_pflags |= TDP_WAKEUP;
515 		return (0);
516 	}
517 
518 	p = td->td_proc;
519 	ttd = tdfind((lwpid_t)uap->id, p->p_pid);
520 	if (ttd == NULL)
521 		return (ESRCH);
522 	thread_lock(ttd);
523 	ttd->td_flags |= TDF_THRWAKEUP;
524 	thread_unlock(ttd);
525 	wakeup((void *)ttd);
526 	PROC_UNLOCK(p);
527 	return (0);
528 }
529 
530 int
531 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
532 {
533 	struct proc *p;
534 	char name[MAXCOMLEN + 1];
535 	struct thread *ttd;
536 	int error;
537 
538 	error = 0;
539 	name[0] = '\0';
540 	if (uap->name != NULL) {
541 		error = copyinstr(uap->name, name, sizeof(name),
542 			NULL);
543 		if (error)
544 			return (error);
545 	}
546 	p = td->td_proc;
547 	ttd = tdfind((lwpid_t)uap->id, p->p_pid);
548 	if (ttd == NULL)
549 		return (ESRCH);
550 	strcpy(ttd->td_name, name);
551 	PROC_UNLOCK(p);
552 	return (error);
553 }
554