xref: /illumos-gate/usr/src/lib/libc/port/threads/thr.c (revision 2570281c)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright (c) 2016 by Delphix. All rights reserved.
25  * Copyright (c) 2017 by The MathWorks, Inc. All rights reserved.
26  */
27 /*
28  * Copyright 2018 Joyent, Inc.
29  */
30 
31 #include "lint.h"
32 #include "thr_uberdata.h"
33 #include <pthread.h>
34 #include <procfs.h>
35 #include <sys/uio.h>
36 #include <ctype.h>
37 #include "libc.h"
38 
39 /*
40  * These symbols should not be exported from libc, but
41  * /lib/libm.so.2 references _thr_main.  libm needs to be fixed.
42  * Also, some older versions of the Studio compiler/debugger
43  * components reference them.  These need to be fixed, too.
44  */
45 #pragma weak _thr_main = thr_main
46 #pragma weak _thr_create = thr_create
47 #pragma weak _thr_join = thr_join
48 #pragma weak _thr_self = thr_self
49 
50 #undef errno
51 extern int errno;
52 
53 /*
54  * Between Solaris 2.5 and Solaris 9, __threaded was used to indicate
55  * "we are linked with libthread".  The Sun Workshop 6 update 1 compilation
56  * system used it illegally (it is a consolidation private symbol).
57  * To accommodate this and possibly other abusers of the symbol,
58  * we make it always equal to 1 now that libthread has been folded
59  * into libc.  The new __libc_threaded symbol is used to indicate
60  * the new meaning, "more than one thread exists".
61  */
62 int __threaded = 1;		/* always equal to 1 */
63 int __libc_threaded = 0;	/* zero until first thr_create() */
64 
65 /*
66  * thr_concurrency and pthread_concurrency are not used by the library.
67  * They exist solely to hold and return the values set by calls to
68  * thr_setconcurrency() and pthread_setconcurrency().
69  * Because thr_concurrency is affected by the THR_NEW_LWP flag
70  * to thr_create(), thr_concurrency is protected by link_lock.
71  */
72 static	int	thr_concurrency = 1;
73 static	int	pthread_concurrency;
74 
75 #define	HASHTBLSZ	1024	/* must be a power of two */
76 #define	TIDHASH(tid, udp)	(tid & (udp)->hash_mask)
77 
78 /* initial allocation, just enough for one lwp */
79 #pragma align 64(init_hash_table)
80 thr_hash_table_t init_hash_table[1] = {
81 	{ DEFAULTMUTEX, DEFAULTCV, NULL },
82 };
83 
84 extern const Lc_interface rtld_funcs[];
85 
86 /*
87  * The weak version is known to libc_db and mdb.
88  */
89 #pragma weak _uberdata = __uberdata
90 uberdata_t __uberdata = {
91 	{ DEFAULTMUTEX, 0, 0 },	/* link_lock */
92 	{ RECURSIVEMUTEX, 0, 0 },	/* ld_lock */
93 	{ RECURSIVEMUTEX, 0, 0 },	/* fork_lock */
94 	{ RECURSIVEMUTEX, 0, 0 },	/* atfork_lock */
95 	{ RECURSIVEMUTEX, 0, 0 },	/* callout_lock */
96 	{ DEFAULTMUTEX, 0, 0 },	/* tdb_hash_lock */
97 	{ 0, },				/* tdb_hash_lock_stats */
98 	{ { 0 }, },			/* siguaction[NSIG] */
99 	{{ DEFAULTMUTEX, NULL, 0 },		/* bucket[NBUCKETS] */
100 	{ DEFAULTMUTEX, NULL, 0 },
101 	{ DEFAULTMUTEX, NULL, 0 },
102 	{ DEFAULTMUTEX, NULL, 0 },
103 	{ DEFAULTMUTEX, NULL, 0 },
104 	{ DEFAULTMUTEX, NULL, 0 },
105 	{ DEFAULTMUTEX, NULL, 0 },
106 	{ DEFAULTMUTEX, NULL, 0 },
107 	{ DEFAULTMUTEX, NULL, 0 },
108 	{ DEFAULTMUTEX, NULL, 0 }},
109 	{ RECURSIVEMUTEX, NULL, NULL },		/* atexit_root */
110 	{ RECURSIVEMUTEX, NULL },		/* quickexit_root */
111 	{ DEFAULTMUTEX, 0, 0, NULL },		/* tsd_metadata */
112 	{ DEFAULTMUTEX, {0, 0}, {0, 0} },	/* tls_metadata */
113 	0,			/* primary_map */
114 	0,			/* bucket_init */
115 	0,			/* pad[0] */
116 	0,			/* pad[1] */
117 	{ 0 },			/* uberflags */
118 	NULL,			/* queue_head */
119 	init_hash_table,	/* thr_hash_table */
120 	1,			/* hash_size: size of the hash table */
121 	0,			/* hash_mask: hash_size - 1 */
122 	NULL,			/* ulwp_one */
123 	NULL,			/* all_lwps */
124 	NULL,			/* all_zombies */
125 	0,			/* nthreads */
126 	0,			/* nzombies */
127 	0,			/* ndaemons */
128 	0,			/* pid */
129 	sigacthandler,		/* sigacthandler */
130 	NULL,			/* lwp_stacks */
131 	NULL,			/* lwp_laststack */
132 	0,			/* nfreestack */
133 	10,			/* thread_stack_cache */
134 	NULL,			/* ulwp_freelist */
135 	NULL,			/* ulwp_lastfree */
136 	NULL,			/* ulwp_replace_free */
137 	NULL,			/* ulwp_replace_last */
138 	NULL,			/* atforklist */
139 	NULL,			/* robustlocks */
140 	NULL,			/* robustlist */
141 	NULL,			/* progname */
142 	NULL,			/* ub_comm_page */
143 	NULL,			/* __tdb_bootstrap */
144 	{			/* tdb */
145 		NULL,		/* tdb_sync_addr_hash */
146 		0,		/* tdb_register_count */
147 		0,		/* tdb_hash_alloc_failed */
148 		NULL,		/* tdb_sync_addr_free */
149 		NULL,		/* tdb_sync_addr_last */
150 		0,		/* tdb_sync_alloc */
151 		{ 0, 0 },	/* tdb_ev_global_mask */
152 		tdb_events,	/* tdb_events array */
153 	},
154 };
155 
156 /*
157  * The weak version is known to libc_db and mdb.
158  */
159 #pragma weak _tdb_bootstrap = __tdb_bootstrap
160 uberdata_t **__tdb_bootstrap = NULL;
161 
162 int	thread_queue_fifo = 4;
163 int	thread_queue_dump = 0;
164 int	thread_cond_wait_defer = 0;
165 int	thread_error_detection = 0;
166 int	thread_async_safe = 0;
167 int	thread_stack_cache = 10;
168 int	thread_door_noreserve = 0;
169 int	thread_locks_misaligned = 0;
170 
171 static	ulwp_t	*ulwp_alloc(void);
172 static	void	ulwp_free(ulwp_t *);
173 
174 /*
175  * Insert the lwp into the hash table.
176  */
177 void
hash_in_unlocked(ulwp_t * ulwp,int ix,uberdata_t * udp)178 hash_in_unlocked(ulwp_t *ulwp, int ix, uberdata_t *udp)
179 {
180 	ulwp->ul_hash = udp->thr_hash_table[ix].hash_bucket;
181 	udp->thr_hash_table[ix].hash_bucket = ulwp;
182 	ulwp->ul_ix = ix;
183 }
184 
185 void
hash_in(ulwp_t * ulwp,uberdata_t * udp)186 hash_in(ulwp_t *ulwp, uberdata_t *udp)
187 {
188 	int ix = TIDHASH(ulwp->ul_lwpid, udp);
189 	mutex_t *mp = &udp->thr_hash_table[ix].hash_lock;
190 
191 	lmutex_lock(mp);
192 	hash_in_unlocked(ulwp, ix, udp);
193 	lmutex_unlock(mp);
194 }
195 
196 /*
197  * Delete the lwp from the hash table.
198  */
199 void
hash_out_unlocked(ulwp_t * ulwp,int ix,uberdata_t * udp)200 hash_out_unlocked(ulwp_t *ulwp, int ix, uberdata_t *udp)
201 {
202 	ulwp_t **ulwpp;
203 
204 	for (ulwpp = &udp->thr_hash_table[ix].hash_bucket;
205 	    ulwp != *ulwpp;
206 	    ulwpp = &(*ulwpp)->ul_hash)
207 		;
208 	*ulwpp = ulwp->ul_hash;
209 	ulwp->ul_hash = NULL;
210 	ulwp->ul_ix = -1;
211 }
212 
213 void
hash_out(ulwp_t * ulwp,uberdata_t * udp)214 hash_out(ulwp_t *ulwp, uberdata_t *udp)
215 {
216 	int ix;
217 
218 	if ((ix = ulwp->ul_ix) >= 0) {
219 		mutex_t *mp = &udp->thr_hash_table[ix].hash_lock;
220 
221 		lmutex_lock(mp);
222 		hash_out_unlocked(ulwp, ix, udp);
223 		lmutex_unlock(mp);
224 	}
225 }
226 
227 /*
228  * Retain stack information for thread structures that are being recycled for
229  * new threads.  All other members of the thread structure should be zeroed.
230  */
231 static void
ulwp_clean(ulwp_t * ulwp)232 ulwp_clean(ulwp_t *ulwp)
233 {
234 	caddr_t stk = ulwp->ul_stk;
235 	size_t mapsiz = ulwp->ul_mapsiz;
236 	size_t guardsize = ulwp->ul_guardsize;
237 	uintptr_t stktop = ulwp->ul_stktop;
238 	size_t stksiz = ulwp->ul_stksiz;
239 
240 	(void) memset(ulwp, 0, sizeof (*ulwp));
241 
242 	ulwp->ul_stk = stk;
243 	ulwp->ul_mapsiz = mapsiz;
244 	ulwp->ul_guardsize = guardsize;
245 	ulwp->ul_stktop = stktop;
246 	ulwp->ul_stksiz = stksiz;
247 }
248 
249 static int stackprot;
250 
251 /*
252  * Answer the question, "Is the lwp in question really dead?"
253  * We must inquire of the operating system to be really sure
254  * because the lwp may have called lwp_exit() but it has not
255  * yet completed the exit.
256  */
257 static int
dead_and_buried(ulwp_t * ulwp)258 dead_and_buried(ulwp_t *ulwp)
259 {
260 	if (ulwp->ul_lwpid == (lwpid_t)(-1))
261 		return (1);
262 	if (ulwp->ul_dead && ulwp->ul_detached &&
263 	    _lwp_kill(ulwp->ul_lwpid, 0) == ESRCH) {
264 		ulwp->ul_lwpid = (lwpid_t)(-1);
265 		return (1);
266 	}
267 	return (0);
268 }
269 
270 /*
271  * Attempt to keep the stack cache within the specified cache limit.
272  */
273 static void
trim_stack_cache(int cache_limit)274 trim_stack_cache(int cache_limit)
275 {
276 	ulwp_t *self = curthread;
277 	uberdata_t *udp = self->ul_uberdata;
278 	ulwp_t *prev = NULL;
279 	ulwp_t **ulwpp = &udp->lwp_stacks;
280 	ulwp_t *ulwp;
281 
282 	ASSERT(udp->nthreads <= 1 || MUTEX_OWNED(&udp->link_lock, self));
283 
284 	while (udp->nfreestack > cache_limit && (ulwp = *ulwpp) != NULL) {
285 		if (dead_and_buried(ulwp)) {
286 			*ulwpp = ulwp->ul_next;
287 			if (ulwp == udp->lwp_laststack)
288 				udp->lwp_laststack = prev;
289 			hash_out(ulwp, udp);
290 			udp->nfreestack--;
291 			(void) munmap(ulwp->ul_stk, ulwp->ul_mapsiz);
292 			/*
293 			 * Now put the free ulwp on the ulwp freelist.
294 			 */
295 			ulwp->ul_mapsiz = 0;
296 			ulwp->ul_next = NULL;
297 			if (udp->ulwp_freelist == NULL)
298 				udp->ulwp_freelist = udp->ulwp_lastfree = ulwp;
299 			else {
300 				udp->ulwp_lastfree->ul_next = ulwp;
301 				udp->ulwp_lastfree = ulwp;
302 			}
303 		} else {
304 			prev = ulwp;
305 			ulwpp = &ulwp->ul_next;
306 		}
307 	}
308 }
309 
310 /*
311  * Find an unused stack of the requested size
312  * or create a new stack of the requested size.
313  * Return a pointer to the ulwp_t structure referring to the stack, or NULL.
314  * thr_exit() stores 1 in the ul_dead member.
315  * thr_join() stores -1 in the ul_lwpid member.
316  */
317 static ulwp_t *
find_stack(size_t stksize,size_t guardsize)318 find_stack(size_t stksize, size_t guardsize)
319 {
320 	static size_t pagesize = 0;
321 
322 	uberdata_t *udp = curthread->ul_uberdata;
323 	size_t mapsize;
324 	ulwp_t *prev;
325 	ulwp_t *ulwp;
326 	ulwp_t **ulwpp;
327 	void *stk;
328 
329 	/*
330 	 * The stack is allocated PROT_READ|PROT_WRITE|PROT_EXEC
331 	 * unless overridden by the system's configuration.
332 	 */
333 	if (stackprot == 0) {	/* do this once */
334 		long lprot = _sysconf(_SC_STACK_PROT);
335 		if (lprot <= 0)
336 			lprot = (PROT_READ|PROT_WRITE|PROT_EXEC);
337 		stackprot = (int)lprot;
338 	}
339 	if (pagesize == 0)	/* do this once */
340 		pagesize = _sysconf(_SC_PAGESIZE);
341 
342 	/*
343 	 * One megabyte stacks by default, but subtract off
344 	 * two pages for the system-created red zones.
345 	 * Round up a non-zero stack size to a pagesize multiple.
346 	 */
347 	if (stksize == 0)
348 		stksize = DEFAULTSTACK - 2 * pagesize;
349 	else
350 		stksize = ((stksize + pagesize - 1) & -pagesize);
351 
352 	/*
353 	 * Round up the mapping size to a multiple of pagesize.
354 	 * Note: mmap() provides at least one page of red zone
355 	 * so we deduct that from the value of guardsize.
356 	 */
357 	if (guardsize != 0)
358 		guardsize = ((guardsize + pagesize - 1) & -pagesize) - pagesize;
359 	mapsize = stksize + guardsize;
360 
361 	lmutex_lock(&udp->link_lock);
362 	for (prev = NULL, ulwpp = &udp->lwp_stacks;
363 	    (ulwp = *ulwpp) != NULL;
364 	    prev = ulwp, ulwpp = &ulwp->ul_next) {
365 		if (ulwp->ul_mapsiz == mapsize &&
366 		    ulwp->ul_guardsize == guardsize &&
367 		    dead_and_buried(ulwp)) {
368 			/*
369 			 * The previous lwp is gone; reuse the stack.
370 			 * Remove the ulwp from the stack list.
371 			 */
372 			*ulwpp = ulwp->ul_next;
373 			ulwp->ul_next = NULL;
374 			if (ulwp == udp->lwp_laststack)
375 				udp->lwp_laststack = prev;
376 			hash_out(ulwp, udp);
377 			udp->nfreestack--;
378 			lmutex_unlock(&udp->link_lock);
379 			ulwp_clean(ulwp);
380 			return (ulwp);
381 		}
382 	}
383 
384 	/*
385 	 * None of the cached stacks matched our mapping size.
386 	 * Reduce the stack cache to get rid of possibly
387 	 * very old stacks that will never be reused.
388 	 */
389 	if (udp->nfreestack > udp->thread_stack_cache)
390 		trim_stack_cache(udp->thread_stack_cache);
391 	else if (udp->nfreestack > 0)
392 		trim_stack_cache(udp->nfreestack - 1);
393 	lmutex_unlock(&udp->link_lock);
394 
395 	/*
396 	 * Create a new stack.
397 	 */
398 	if ((stk = mmap(NULL, mapsize, stackprot,
399 	    MAP_PRIVATE|MAP_NORESERVE|MAP_ANON, -1, (off_t)0)) != MAP_FAILED) {
400 		/*
401 		 * We have allocated our stack.  Now allocate the ulwp.
402 		 */
403 		ulwp = ulwp_alloc();
404 		if (ulwp == NULL)
405 			(void) munmap(stk, mapsize);
406 		else {
407 			ulwp->ul_stk = stk;
408 			ulwp->ul_mapsiz = mapsize;
409 			ulwp->ul_guardsize = guardsize;
410 			ulwp->ul_stktop = (uintptr_t)stk + mapsize;
411 			ulwp->ul_stksiz = stksize;
412 			if (guardsize)	/* protect the extra red zone */
413 				(void) mprotect(stk, guardsize, PROT_NONE);
414 		}
415 	}
416 	return (ulwp);
417 }
418 
419 /*
420  * Get a ulwp_t structure from the free list or allocate a new one.
421  * Such ulwp_t's do not have a stack allocated by the library.
422  */
423 static ulwp_t *
ulwp_alloc(void)424 ulwp_alloc(void)
425 {
426 	ulwp_t *self = curthread;
427 	uberdata_t *udp = self->ul_uberdata;
428 	size_t tls_size;
429 	ulwp_t *prev;
430 	ulwp_t *ulwp;
431 	ulwp_t **ulwpp;
432 	caddr_t data;
433 
434 	lmutex_lock(&udp->link_lock);
435 	for (prev = NULL, ulwpp = &udp->ulwp_freelist;
436 	    (ulwp = *ulwpp) != NULL;
437 	    prev = ulwp, ulwpp = &ulwp->ul_next) {
438 		if (dead_and_buried(ulwp)) {
439 			*ulwpp = ulwp->ul_next;
440 			ulwp->ul_next = NULL;
441 			if (ulwp == udp->ulwp_lastfree)
442 				udp->ulwp_lastfree = prev;
443 			hash_out(ulwp, udp);
444 			lmutex_unlock(&udp->link_lock);
445 			ulwp_clean(ulwp);
446 			return (ulwp);
447 		}
448 	}
449 	lmutex_unlock(&udp->link_lock);
450 
451 	tls_size = roundup64(udp->tls_metadata.static_tls.tls_size);
452 	data = lmalloc(sizeof (*ulwp) + tls_size);
453 	if (data != NULL) {
454 		/* LINTED pointer cast may result in improper alignment */
455 		ulwp = (ulwp_t *)(data + tls_size);
456 	}
457 	return (ulwp);
458 }
459 
460 /*
461  * Free a ulwp structure.
462  * If there is an associated stack, put it on the stack list and
463  * munmap() previously freed stacks up to the residual cache limit.
464  * Else put it on the ulwp free list and never call lfree() on it.
465  */
466 static void
ulwp_free(ulwp_t * ulwp)467 ulwp_free(ulwp_t *ulwp)
468 {
469 	uberdata_t *udp = curthread->ul_uberdata;
470 
471 	ASSERT(udp->nthreads <= 1 || MUTEX_OWNED(&udp->link_lock, curthread));
472 	ulwp->ul_next = NULL;
473 	if (ulwp == udp->ulwp_one)	/* don't reuse the primoridal stack */
474 		/*EMPTY*/;
475 	else if (ulwp->ul_mapsiz != 0) {
476 		if (udp->lwp_stacks == NULL)
477 			udp->lwp_stacks = udp->lwp_laststack = ulwp;
478 		else {
479 			udp->lwp_laststack->ul_next = ulwp;
480 			udp->lwp_laststack = ulwp;
481 		}
482 		if (++udp->nfreestack > udp->thread_stack_cache)
483 			trim_stack_cache(udp->thread_stack_cache);
484 	} else {
485 		if (udp->ulwp_freelist == NULL)
486 			udp->ulwp_freelist = udp->ulwp_lastfree = ulwp;
487 		else {
488 			udp->ulwp_lastfree->ul_next = ulwp;
489 			udp->ulwp_lastfree = ulwp;
490 		}
491 	}
492 }
493 
494 /*
495  * Find a named lwp and return a pointer to its hash list location.
496  * On success, returns with the hash lock held.
497  */
498 ulwp_t **
find_lwpp(thread_t tid)499 find_lwpp(thread_t tid)
500 {
501 	uberdata_t *udp = curthread->ul_uberdata;
502 	int ix = TIDHASH(tid, udp);
503 	mutex_t *mp = &udp->thr_hash_table[ix].hash_lock;
504 	ulwp_t *ulwp;
505 	ulwp_t **ulwpp;
506 
507 	if (tid == 0)
508 		return (NULL);
509 
510 	lmutex_lock(mp);
511 	for (ulwpp = &udp->thr_hash_table[ix].hash_bucket;
512 	    (ulwp = *ulwpp) != NULL;
513 	    ulwpp = &ulwp->ul_hash) {
514 		if (ulwp->ul_lwpid == tid)
515 			return (ulwpp);
516 	}
517 	lmutex_unlock(mp);
518 	return (NULL);
519 }
520 
521 /*
522  * Wake up all lwps waiting on this lwp for some reason.
523  */
524 void
ulwp_broadcast(ulwp_t * ulwp)525 ulwp_broadcast(ulwp_t *ulwp)
526 {
527 	ulwp_t *self = curthread;
528 	uberdata_t *udp = self->ul_uberdata;
529 
530 	ASSERT(MUTEX_OWNED(ulwp_mutex(ulwp, udp), self));
531 	(void) cond_broadcast(ulwp_condvar(ulwp, udp));
532 }
533 
534 /*
535  * Find a named lwp and return a pointer to it.
536  * Returns with the hash lock held.
537  */
538 ulwp_t *
find_lwp(thread_t tid)539 find_lwp(thread_t tid)
540 {
541 	ulwp_t *self = curthread;
542 	uberdata_t *udp = self->ul_uberdata;
543 	ulwp_t *ulwp = NULL;
544 	ulwp_t **ulwpp;
545 
546 	if (self->ul_lwpid == tid) {
547 		ulwp = self;
548 		ulwp_lock(ulwp, udp);
549 	} else if ((ulwpp = find_lwpp(tid)) != NULL) {
550 		ulwp = *ulwpp;
551 	}
552 
553 	if (ulwp && ulwp->ul_dead) {
554 		ulwp_unlock(ulwp, udp);
555 		ulwp = NULL;
556 	}
557 
558 	return (ulwp);
559 }
560 
561 int
_thrp_create(void * stk,size_t stksize,void * (* func)(void *),void * arg,long flags,thread_t * new_thread,size_t guardsize,const char * name)562 _thrp_create(void *stk, size_t stksize, void *(*func)(void *), void *arg,
563     long flags, thread_t *new_thread, size_t guardsize, const char *name)
564 {
565 	ulwp_t *self = curthread;
566 	uberdata_t *udp = self->ul_uberdata;
567 	ucontext_t uc;
568 	uint_t lwp_flags;
569 	thread_t tid;
570 	int error;
571 	ulwp_t *ulwp;
572 
573 	/*
574 	 * Enforce the restriction of not creating any threads
575 	 * until the primary link map has been initialized.
576 	 * Also, disallow thread creation to a child of vfork().
577 	 */
578 	if (!self->ul_primarymap || self->ul_vfork)
579 		return (ENOTSUP);
580 
581 	if (udp->hash_size == 1)
582 		finish_init();
583 
584 	if ((stk || stksize) && stksize < MINSTACK)
585 		return (EINVAL);
586 
587 	if (stk == NULL) {
588 		if ((ulwp = find_stack(stksize, guardsize)) == NULL)
589 			return (ENOMEM);
590 		stksize = ulwp->ul_mapsiz - ulwp->ul_guardsize;
591 	} else {
592 		/* initialize the private stack */
593 		if ((ulwp = ulwp_alloc()) == NULL)
594 			return (ENOMEM);
595 		ulwp->ul_stk = stk;
596 		ulwp->ul_stktop = (uintptr_t)stk + stksize;
597 		ulwp->ul_stksiz = stksize;
598 	}
599 	/* ulwp is not in the hash table; make sure hash_out() doesn't fail */
600 	ulwp->ul_ix = -1;
601 	ulwp->ul_errnop = &ulwp->ul_errno;
602 
603 	lwp_flags = LWP_SUSPENDED;
604 	if (flags & (THR_DETACHED|THR_DAEMON)) {
605 		flags |= THR_DETACHED;
606 		lwp_flags |= LWP_DETACHED;
607 	}
608 	if (flags & THR_DAEMON)
609 		lwp_flags |= LWP_DAEMON;
610 
611 	/* creating a thread: enforce mt-correctness in mutex_lock() */
612 	self->ul_async_safe = 1;
613 
614 	/* per-thread copies of global variables, for speed */
615 	ulwp->ul_queue_fifo = self->ul_queue_fifo;
616 	ulwp->ul_cond_wait_defer = self->ul_cond_wait_defer;
617 	ulwp->ul_error_detection = self->ul_error_detection;
618 	ulwp->ul_async_safe = self->ul_async_safe;
619 	ulwp->ul_max_spinners = self->ul_max_spinners;
620 	ulwp->ul_adaptive_spin = self->ul_adaptive_spin;
621 	ulwp->ul_queue_spin = self->ul_queue_spin;
622 	ulwp->ul_door_noreserve = self->ul_door_noreserve;
623 	ulwp->ul_misaligned = self->ul_misaligned;
624 
625 	/* new thread inherits creating thread's scheduling parameters */
626 	ulwp->ul_policy = self->ul_policy;
627 	ulwp->ul_pri = (self->ul_epri? self->ul_epri : self->ul_pri);
628 	ulwp->ul_cid = self->ul_cid;
629 	ulwp->ul_rtclassid = self->ul_rtclassid;
630 
631 	ulwp->ul_primarymap = self->ul_primarymap;
632 	ulwp->ul_self = ulwp;
633 	ulwp->ul_uberdata = udp;
634 
635 	/* debugger support */
636 	ulwp->ul_usropts = flags;
637 
638 #ifdef __sparc
639 	/*
640 	 * We cache several instructions in the thread structure for use
641 	 * by the fasttrap DTrace provider. When changing this, read the
642 	 * comment in fasttrap.h for the all the other places that must
643 	 * be changed.
644 	 */
645 	ulwp->ul_dsave = 0x9de04000;	/* save %g1, %g0, %sp */
646 	ulwp->ul_drestore = 0x81e80000;	/* restore %g0, %g0, %g0 */
647 	ulwp->ul_dftret = 0x91d0203a;	/* ta 0x3a */
648 	ulwp->ul_dreturn = 0x81ca0000;	/* return %o0 */
649 #endif
650 
651 	ulwp->ul_startpc = func;
652 	ulwp->ul_startarg = arg;
653 	_fpinherit(ulwp);
654 	/*
655 	 * Defer signals on the new thread until its TLS constructors
656 	 * have been called.  _thrp_setup() will call sigon() after
657 	 * it has called tls_setup().
658 	 */
659 	ulwp->ul_sigdefer = 1;
660 
661 	error = setup_context(&uc, _thrp_setup, ulwp,
662 	    (caddr_t)ulwp->ul_stk + ulwp->ul_guardsize, stksize);
663 	if (error != 0 && stk != NULL)	/* inaccessible stack */
664 		error = EFAULT;
665 
666 	/*
667 	 * Call enter_critical() to avoid being suspended until we
668 	 * have linked the new thread into the proper lists.
669 	 * This is necessary because forkall() and fork1() must
670 	 * suspend all threads and they must see a complete list.
671 	 */
672 	enter_critical(self);
673 	uc.uc_sigmask = ulwp->ul_sigmask = self->ul_sigmask;
674 	if (error != 0 ||
675 	    (error = __lwp_create(&uc, lwp_flags, &tid)) != 0) {
676 		exit_critical(self);
677 		ulwp->ul_lwpid = (lwpid_t)(-1);
678 		ulwp->ul_dead = 1;
679 		ulwp->ul_detached = 1;
680 		lmutex_lock(&udp->link_lock);
681 		ulwp_free(ulwp);
682 		lmutex_unlock(&udp->link_lock);
683 		return (error);
684 	}
685 	self->ul_nocancel = 0;	/* cancellation is now possible */
686 	udp->uberflags.uf_mt = 1;
687 	if (new_thread)
688 		*new_thread = tid;
689 	if (flags & THR_DETACHED)
690 		ulwp->ul_detached = 1;
691 	ulwp->ul_lwpid = tid;
692 	ulwp->ul_stop = TSTP_REGULAR;
693 	if (flags & THR_SUSPENDED)
694 		ulwp->ul_created = 1;
695 
696 	lmutex_lock(&udp->link_lock);
697 	ulwp->ul_forw = udp->all_lwps;
698 	ulwp->ul_back = udp->all_lwps->ul_back;
699 	ulwp->ul_back->ul_forw = ulwp;
700 	ulwp->ul_forw->ul_back = ulwp;
701 	hash_in(ulwp, udp);
702 	udp->nthreads++;
703 	if (flags & THR_DAEMON)
704 		udp->ndaemons++;
705 	if (flags & THR_NEW_LWP)
706 		thr_concurrency++;
707 	__libc_threaded = 1;		/* inform stdio */
708 	lmutex_unlock(&udp->link_lock);
709 
710 	if (__td_event_report(self, TD_CREATE, udp)) {
711 		self->ul_td_evbuf.eventnum = TD_CREATE;
712 		self->ul_td_evbuf.eventdata = (void *)(uintptr_t)tid;
713 		tdb_event(TD_CREATE, udp);
714 	}
715 
716 	exit_critical(self);
717 
718 	if (name != NULL && name[0] != '\0')
719 		(void) pthread_setname_np(tid, name);
720 
721 	if (!(flags & THR_SUSPENDED))
722 		(void) _thrp_continue(tid, TSTP_REGULAR);
723 
724 	return (0);
725 }
726 
727 int
thr_create(void * stk,size_t stksize,void * (* func)(void *),void * arg,long flags,thread_t * new_thread)728 thr_create(void *stk, size_t stksize, void *(*func)(void *), void *arg,
729     long flags, thread_t *new_thread)
730 {
731 	return (_thrp_create(stk, stksize, func, arg, flags, new_thread, 0,
732 	    NULL));
733 }
734 
735 /*
736  * A special cancellation cleanup hook for DCE.
737  * cleanuphndlr, when it is not NULL, will contain a callback
738  * function to be called before a thread is terminated in
739  * thr_exit() as a result of being cancelled.
740  */
741 static void (*cleanuphndlr)(void) = NULL;
742 
743 /*
744  * _pthread_setcleanupinit: sets the cleanup hook.
745  */
746 int
_pthread_setcleanupinit(void (* func)(void))747 _pthread_setcleanupinit(void (*func)(void))
748 {
749 	cleanuphndlr = func;
750 	return (0);
751 }
752 
753 void
_thrp_exit()754 _thrp_exit()
755 {
756 	ulwp_t *self = curthread;
757 	uberdata_t *udp = self->ul_uberdata;
758 	ulwp_t *replace = NULL;
759 
760 	if (__td_event_report(self, TD_DEATH, udp)) {
761 		self->ul_td_evbuf.eventnum = TD_DEATH;
762 		tdb_event(TD_DEATH, udp);
763 	}
764 
765 	ASSERT(self->ul_sigdefer != 0);
766 
767 	lmutex_lock(&udp->link_lock);
768 	udp->nthreads--;
769 	if (self->ul_usropts & THR_NEW_LWP)
770 		thr_concurrency--;
771 	if (self->ul_usropts & THR_DAEMON)
772 		udp->ndaemons--;
773 	else if (udp->nthreads == udp->ndaemons) {
774 		/*
775 		 * We are the last non-daemon thread exiting.
776 		 * Exit the process.  We retain our TSD and TLS so
777 		 * that atexit() application functions can use them.
778 		 */
779 		lmutex_unlock(&udp->link_lock);
780 		exit(0);
781 		thr_panic("_thrp_exit(): exit(0) returned");
782 	}
783 	lmutex_unlock(&udp->link_lock);
784 
785 	/*
786 	 * tsd_exit() may call its destructor free(), thus depending on
787 	 * tmem, therefore tmem_exit() needs to be called after tsd_exit()
788 	 * and tls_exit().
789 	 */
790 	tsd_exit();		/* deallocate thread-specific data */
791 	tls_exit();		/* deallocate thread-local storage */
792 	tmem_exit();		/* deallocate tmem allocations */
793 	heldlock_exit();	/* deal with left-over held locks */
794 
795 	/* block all signals to finish exiting */
796 	block_all_signals(self);
797 	/* also prevent ourself from being suspended */
798 	enter_critical(self);
799 	rwl_free(self);
800 	lmutex_lock(&udp->link_lock);
801 	ulwp_free(self);
802 	(void) ulwp_lock(self, udp);
803 
804 	if (self->ul_mapsiz && !self->ul_detached) {
805 		/*
806 		 * We want to free the stack for reuse but must keep
807 		 * the ulwp_t struct for the benefit of thr_join().
808 		 * For this purpose we allocate a replacement ulwp_t.
809 		 */
810 		if ((replace = udp->ulwp_replace_free) == NULL)
811 			replace = lmalloc(REPLACEMENT_SIZE);
812 		else if ((udp->ulwp_replace_free = replace->ul_next) == NULL)
813 			udp->ulwp_replace_last = NULL;
814 	}
815 
816 	if (udp->all_lwps == self)
817 		udp->all_lwps = self->ul_forw;
818 	if (udp->all_lwps == self)
819 		udp->all_lwps = NULL;
820 	else {
821 		self->ul_forw->ul_back = self->ul_back;
822 		self->ul_back->ul_forw = self->ul_forw;
823 	}
824 	self->ul_forw = self->ul_back = NULL;
825 #if defined(THREAD_DEBUG)
826 	/* collect queue lock statistics before marking ourself dead */
827 	record_spin_locks(self);
828 #endif
829 	self->ul_dead = 1;
830 	self->ul_pleasestop = 0;
831 	if (replace != NULL) {
832 		int ix = self->ul_ix;		/* the hash index */
833 		(void) memcpy(replace, self, REPLACEMENT_SIZE);
834 		replace->ul_self = replace;
835 		replace->ul_next = NULL;	/* clone not on stack list */
836 		replace->ul_mapsiz = 0;		/* allows clone to be freed */
837 		replace->ul_replace = 1;	/* requires clone to be freed */
838 		hash_out_unlocked(self, ix, udp);
839 		hash_in_unlocked(replace, ix, udp);
840 		ASSERT(!(self->ul_detached));
841 		self->ul_detached = 1;		/* this frees the stack */
842 		self->ul_schedctl = NULL;
843 		self->ul_schedctl_called = &udp->uberflags;
844 		set_curthread(self = replace);
845 		/*
846 		 * Having just changed the address of curthread, we
847 		 * must reset the ownership of the locks we hold so
848 		 * that assertions will not fire when we release them.
849 		 */
850 		udp->link_lock.mutex_owner = (uintptr_t)self;
851 		ulwp_mutex(self, udp)->mutex_owner = (uintptr_t)self;
852 		/*
853 		 * NOTE:
854 		 * On i386, %gs still references the original, not the
855 		 * replacement, ulwp structure.  Fetching the replacement
856 		 * curthread pointer via %gs:0 works correctly since the
857 		 * original ulwp structure will not be reallocated until
858 		 * this lwp has completed its lwp_exit() system call (see
859 		 * dead_and_buried()), but from here on out, we must make
860 		 * no references to %gs:<offset> other than %gs:0.
861 		 */
862 	}
863 	/*
864 	 * Put non-detached terminated threads in the all_zombies list.
865 	 */
866 	if (!self->ul_detached) {
867 		udp->nzombies++;
868 		if (udp->all_zombies == NULL) {
869 			ASSERT(udp->nzombies == 1);
870 			udp->all_zombies = self->ul_forw = self->ul_back = self;
871 		} else {
872 			self->ul_forw = udp->all_zombies;
873 			self->ul_back = udp->all_zombies->ul_back;
874 			self->ul_back->ul_forw = self;
875 			self->ul_forw->ul_back = self;
876 		}
877 	}
878 	/*
879 	 * Notify everyone waiting for this thread.
880 	 */
881 	ulwp_broadcast(self);
882 	(void) ulwp_unlock(self, udp);
883 	/*
884 	 * Prevent any more references to the schedctl data.
885 	 * We are exiting and continue_fork() may not find us.
886 	 * Do this just before dropping link_lock, since fork
887 	 * serializes on link_lock.
888 	 */
889 	self->ul_schedctl = NULL;
890 	self->ul_schedctl_called = &udp->uberflags;
891 	lmutex_unlock(&udp->link_lock);
892 
893 	ASSERT(self->ul_critical == 1);
894 	ASSERT(self->ul_preempt == 0);
895 	_lwp_terminate();	/* never returns */
896 	thr_panic("_thrp_exit(): _lwp_terminate() returned");
897 }
898 
899 #if defined(THREAD_DEBUG)
900 void
collect_queue_statistics()901 collect_queue_statistics()
902 {
903 	uberdata_t *udp = curthread->ul_uberdata;
904 	ulwp_t *ulwp;
905 
906 	if (thread_queue_dump) {
907 		lmutex_lock(&udp->link_lock);
908 		if ((ulwp = udp->all_lwps) != NULL) {
909 			do {
910 				record_spin_locks(ulwp);
911 			} while ((ulwp = ulwp->ul_forw) != udp->all_lwps);
912 		}
913 		lmutex_unlock(&udp->link_lock);
914 	}
915 }
916 #endif
917 
918 static void __NORETURN
_thrp_exit_common(void * status,int unwind)919 _thrp_exit_common(void *status, int unwind)
920 {
921 	ulwp_t *self = curthread;
922 	int cancelled = (self->ul_cancel_pending && status == PTHREAD_CANCELED);
923 
924 	ASSERT(self->ul_critical == 0 && self->ul_preempt == 0);
925 
926 	/*
927 	 * Disable cancellation and call the special DCE cancellation
928 	 * cleanup hook if it is enabled.  Do nothing else before calling
929 	 * the DCE cancellation cleanup hook; it may call longjmp() and
930 	 * never return here.
931 	 */
932 	self->ul_cancel_disabled = 1;
933 	self->ul_cancel_async = 0;
934 	self->ul_save_async = 0;
935 	self->ul_cancelable = 0;
936 	self->ul_cancel_pending = 0;
937 	set_cancel_pending_flag(self, 1);
938 	if (cancelled && cleanuphndlr != NULL)
939 		(*cleanuphndlr)();
940 
941 	/*
942 	 * Block application signals while we are exiting.
943 	 * We call out to C++, TSD, and TLS destructors while exiting
944 	 * and these are application-defined, so we cannot be assured
945 	 * that they won't reset the signal mask.  We use sigoff() to
946 	 * defer any signals that may be received as a result of this
947 	 * bad behavior.  Such signals will be lost to the process
948 	 * when the thread finishes exiting.
949 	 */
950 	(void) thr_sigsetmask(SIG_SETMASK, &maskset, NULL);
951 	sigoff(self);
952 
953 	self->ul_rval = status;
954 
955 	/*
956 	 * If thr_exit is being called from the places where
957 	 * C++ destructors are to be called such as cancellation
958 	 * points, then set this flag. It is checked in _t_cancel()
959 	 * to decide whether _ex_unwind() is to be called or not.
960 	 */
961 	if (unwind)
962 		self->ul_unwind = 1;
963 
964 	/*
965 	 * _thrp_unwind() will eventually call _thrp_exit().
966 	 * It never returns.
967 	 */
968 	_thrp_unwind(NULL);
969 	thr_panic("_thrp_exit_common(): _thrp_unwind() returned");
970 
971 	for (;;)	/* to shut the compiler up about __NORETURN */
972 		continue;
973 }
974 
975 /*
976  * Called when a thread returns from its start function.
977  * We are at the top of the stack; no unwinding is necessary.
978  */
979 void
_thrp_terminate(void * status)980 _thrp_terminate(void *status)
981 {
982 	_thrp_exit_common(status, 0);
983 }
984 
985 #pragma weak pthread_exit = thr_exit
986 #pragma weak _thr_exit = thr_exit
987 void
thr_exit(void * status)988 thr_exit(void *status)
989 {
990 	_thrp_exit_common(status, 1);
991 }
992 
993 int
_thrp_join(thread_t tid,thread_t * departed,void ** status,int do_cancel)994 _thrp_join(thread_t tid, thread_t *departed, void **status, int do_cancel)
995 {
996 	uberdata_t *udp = curthread->ul_uberdata;
997 	mutex_t *mp;
998 	void *rval;
999 	thread_t found;
1000 	ulwp_t *ulwp;
1001 	ulwp_t **ulwpp;
1002 	int replace;
1003 	int error;
1004 
1005 	if (do_cancel)
1006 		error = lwp_wait(tid, &found);
1007 	else {
1008 		while ((error = __lwp_wait(tid, &found)) == EINTR)
1009 			;
1010 	}
1011 	if (error)
1012 		return (error);
1013 
1014 	/*
1015 	 * We must hold link_lock to avoid a race condition with find_stack().
1016 	 */
1017 	lmutex_lock(&udp->link_lock);
1018 	if ((ulwpp = find_lwpp(found)) == NULL) {
1019 		/*
1020 		 * lwp_wait() found an lwp that the library doesn't know
1021 		 * about.  It must have been created with _lwp_create().
1022 		 * Just return its lwpid; we can't know its status.
1023 		 */
1024 		lmutex_unlock(&udp->link_lock);
1025 		rval = NULL;
1026 	} else {
1027 		/*
1028 		 * Remove ulwp from the hash table.
1029 		 */
1030 		ulwp = *ulwpp;
1031 		*ulwpp = ulwp->ul_hash;
1032 		ulwp->ul_hash = NULL;
1033 		/*
1034 		 * Remove ulwp from all_zombies list.
1035 		 */
1036 		ASSERT(udp->nzombies >= 1);
1037 		if (udp->all_zombies == ulwp)
1038 			udp->all_zombies = ulwp->ul_forw;
1039 		if (udp->all_zombies == ulwp)
1040 			udp->all_zombies = NULL;
1041 		else {
1042 			ulwp->ul_forw->ul_back = ulwp->ul_back;
1043 			ulwp->ul_back->ul_forw = ulwp->ul_forw;
1044 		}
1045 		ulwp->ul_forw = ulwp->ul_back = NULL;
1046 		udp->nzombies--;
1047 		ASSERT(ulwp->ul_dead && !ulwp->ul_detached &&
1048 		    !(ulwp->ul_usropts & (THR_DETACHED|THR_DAEMON)));
1049 		/*
1050 		 * We can't call ulwp_unlock(ulwp) after we set
1051 		 * ulwp->ul_ix = -1 so we have to get a pointer to the
1052 		 * ulwp's hash table mutex now in order to unlock it below.
1053 		 */
1054 		mp = ulwp_mutex(ulwp, udp);
1055 		ulwp->ul_lwpid = (lwpid_t)(-1);
1056 		ulwp->ul_ix = -1;
1057 		rval = ulwp->ul_rval;
1058 		replace = ulwp->ul_replace;
1059 		lmutex_unlock(mp);
1060 		if (replace) {
1061 			ulwp->ul_next = NULL;
1062 			if (udp->ulwp_replace_free == NULL)
1063 				udp->ulwp_replace_free =
1064 				    udp->ulwp_replace_last = ulwp;
1065 			else {
1066 				udp->ulwp_replace_last->ul_next = ulwp;
1067 				udp->ulwp_replace_last = ulwp;
1068 			}
1069 		}
1070 		lmutex_unlock(&udp->link_lock);
1071 	}
1072 
1073 	if (departed != NULL)
1074 		*departed = found;
1075 	if (status != NULL)
1076 		*status = rval;
1077 	return (0);
1078 }
1079 
1080 int
thr_join(thread_t tid,thread_t * departed,void ** status)1081 thr_join(thread_t tid, thread_t *departed, void **status)
1082 {
1083 	int error = _thrp_join(tid, departed, status, 1);
1084 	return ((error == EINVAL)? ESRCH : error);
1085 }
1086 
1087 /*
1088  * pthread_join() differs from Solaris thr_join():
1089  * It does not return the departed thread's id
1090  * and hence does not have a "departed" argument.
1091  * It returns EINVAL if tid refers to a detached thread.
1092  */
1093 #pragma weak _pthread_join = pthread_join
1094 int
pthread_join(pthread_t tid,void ** status)1095 pthread_join(pthread_t tid, void **status)
1096 {
1097 	return ((tid == 0)? ESRCH : _thrp_join(tid, NULL, status, 1));
1098 }
1099 
1100 int
pthread_detach(pthread_t tid)1101 pthread_detach(pthread_t tid)
1102 {
1103 	uberdata_t *udp = curthread->ul_uberdata;
1104 	ulwp_t *ulwp;
1105 	ulwp_t **ulwpp;
1106 	int error = 0;
1107 
1108 	if ((ulwpp = find_lwpp(tid)) == NULL)
1109 		return (ESRCH);
1110 	ulwp = *ulwpp;
1111 
1112 	if (ulwp->ul_dead) {
1113 		ulwp_unlock(ulwp, udp);
1114 		error = _thrp_join(tid, NULL, NULL, 0);
1115 	} else {
1116 		error = __lwp_detach(tid);
1117 		ulwp->ul_detached = 1;
1118 		ulwp->ul_usropts |= THR_DETACHED;
1119 		ulwp_unlock(ulwp, udp);
1120 	}
1121 	return (error);
1122 }
1123 
1124 static const char *
ematch(const char * ev,const char * match)1125 ematch(const char *ev, const char *match)
1126 {
1127 	int c;
1128 
1129 	while ((c = *match++) != '\0') {
1130 		if (*ev++ != c)
1131 			return (NULL);
1132 	}
1133 	if (*ev++ != '=')
1134 		return (NULL);
1135 	return (ev);
1136 }
1137 
1138 static int
envvar(const char * ev,const char * match,int limit)1139 envvar(const char *ev, const char *match, int limit)
1140 {
1141 	int val = -1;
1142 	const char *ename;
1143 
1144 	if ((ename = ematch(ev, match)) != NULL) {
1145 		int c;
1146 		for (val = 0; (c = *ename) != '\0'; ename++) {
1147 			if (!isdigit(c)) {
1148 				val = -1;
1149 				break;
1150 			}
1151 			val = val * 10 + (c - '0');
1152 			if (val > limit) {
1153 				val = limit;
1154 				break;
1155 			}
1156 		}
1157 	}
1158 	return (val);
1159 }
1160 
1161 static void
etest(const char * ev)1162 etest(const char *ev)
1163 {
1164 	int value;
1165 
1166 	if ((value = envvar(ev, "QUEUE_SPIN", 1000000)) >= 0)
1167 		thread_queue_spin = value;
1168 	if ((value = envvar(ev, "ADAPTIVE_SPIN", 1000000)) >= 0)
1169 		thread_adaptive_spin = value;
1170 	if ((value = envvar(ev, "MAX_SPINNERS", 255)) >= 0)
1171 		thread_max_spinners = value;
1172 	if ((value = envvar(ev, "QUEUE_FIFO", 8)) >= 0)
1173 		thread_queue_fifo = value;
1174 #if defined(THREAD_DEBUG)
1175 	if ((value = envvar(ev, "QUEUE_VERIFY", 1)) >= 0)
1176 		thread_queue_verify = value;
1177 	if ((value = envvar(ev, "QUEUE_DUMP", 1)) >= 0)
1178 		thread_queue_dump = value;
1179 #endif
1180 	if ((value = envvar(ev, "STACK_CACHE", 10000)) >= 0)
1181 		thread_stack_cache = value;
1182 	if ((value = envvar(ev, "COND_WAIT_DEFER", 1)) >= 0)
1183 		thread_cond_wait_defer = value;
1184 	if ((value = envvar(ev, "ERROR_DETECTION", 2)) >= 0)
1185 		thread_error_detection = value;
1186 	if ((value = envvar(ev, "ASYNC_SAFE", 1)) >= 0)
1187 		thread_async_safe = value;
1188 	if ((value = envvar(ev, "DOOR_NORESERVE", 1)) >= 0)
1189 		thread_door_noreserve = value;
1190 	if ((value = envvar(ev, "LOCKS_MISALIGNED", 1)) >= 0)
1191 		thread_locks_misaligned = value;
1192 }
1193 
1194 /*
1195  * Look for and evaluate environment variables of the form "_THREAD_*".
1196  * For compatibility with the past, we also look for environment
1197  * names of the form "LIBTHREAD_*".
1198  */
1199 static void
set_thread_vars()1200 set_thread_vars()
1201 {
1202 	extern const char **_environ;
1203 	const char **pev;
1204 	const char *ev;
1205 	char c;
1206 
1207 	if ((pev = _environ) == NULL)
1208 		return;
1209 	while ((ev = *pev++) != NULL) {
1210 		c = *ev;
1211 		if (c == '_' && strncmp(ev, "_THREAD_", 8) == 0)
1212 			etest(ev + 8);
1213 		if (c == 'L' && strncmp(ev, "LIBTHREAD_", 10) == 0)
1214 			etest(ev + 10);
1215 	}
1216 }
1217 
1218 /* same as atexit() but private to the library */
1219 extern int _atexit(void (*)(void));
1220 
1221 /* same as _cleanup() but private to the library */
1222 extern void __cleanup(void);
1223 
1224 extern void atfork_init(void);
1225 
1226 #ifdef __amd64
1227 extern void __proc64id(void);
1228 #endif
1229 
1230 static void
init_auxv_data(uberdata_t * udp)1231 init_auxv_data(uberdata_t *udp)
1232 {
1233 	Dl_argsinfo_t args;
1234 
1235 	udp->ub_comm_page = NULL;
1236 	if (dlinfo(RTLD_SELF, RTLD_DI_ARGSINFO, &args) < 0)
1237 		return;
1238 
1239 	while (args.dla_auxv->a_type != AT_NULL) {
1240 		if (args.dla_auxv->a_type == AT_SUN_COMMPAGE) {
1241 			udp->ub_comm_page = args.dla_auxv->a_un.a_ptr;
1242 		}
1243 		args.dla_auxv++;
1244 	}
1245 }
1246 
1247 /*
1248  * libc_init() is called by ld.so.1 for library initialization.
1249  * We perform minimal initialization; enough to work with the main thread.
1250  */
1251 void
libc_init(void)1252 libc_init(void)
1253 {
1254 	uberdata_t *udp = &__uberdata;
1255 	ulwp_t *oldself = __curthread();
1256 	ucontext_t uc;
1257 	ulwp_t *self;
1258 	struct rlimit rl;
1259 	caddr_t data;
1260 	size_t tls_size;
1261 	int setmask;
1262 
1263 	/*
1264 	 * For the initial stage of initialization, we must be careful
1265 	 * not to call any function that could possibly call _cerror().
1266 	 * For this purpose, we call only the raw system call wrappers.
1267 	 */
1268 
1269 #ifdef __amd64
1270 	/*
1271 	 * Gather information about cache layouts for optimized
1272 	 * AMD and Intel assembler strfoo() and memfoo() functions.
1273 	 */
1274 	__proc64id();
1275 #endif
1276 
1277 	/*
1278 	 * Every libc, regardless of which link map, must register __cleanup().
1279 	 */
1280 	(void) _atexit(__cleanup);
1281 
1282 	/*
1283 	 * Every libc, regardless of link map, needs to go through and check
1284 	 * its aux vectors.  Doing so will indicate whether or not this has
1285 	 * been given a comm page (to optimize certain system actions).
1286 	 */
1287 	init_auxv_data(udp);
1288 
1289 	/*
1290 	 * We keep our uberdata on one of (a) the first alternate link map
1291 	 * or (b) the primary link map.  We switch to the primary link map
1292 	 * and stay there once we see it.  All intermediate link maps are
1293 	 * subject to being unloaded at any time.
1294 	 */
1295 	if (oldself != NULL && (oldself->ul_primarymap || !primary_link_map)) {
1296 		__tdb_bootstrap = oldself->ul_uberdata->tdb_bootstrap;
1297 		/*
1298 		 * Each link map has its own copy of the stack protector guard
1299 		 * and must always be initialized.
1300 		 */
1301 		ssp_init();
1302 		mutex_setup();
1303 		atfork_init();	/* every link map needs atfork() processing */
1304 		init_progname();
1305 		return;
1306 	}
1307 
1308 	/*
1309 	 * To establish the main stack information, we have to get our context.
1310 	 * This is also convenient to use for getting our signal mask.
1311 	 */
1312 	uc.uc_flags = UC_ALL;
1313 	(void) __getcontext(&uc);
1314 	ASSERT(uc.uc_link == NULL);
1315 
1316 	tls_size = roundup64(udp->tls_metadata.static_tls.tls_size);
1317 	ASSERT(primary_link_map || tls_size == 0);
1318 	data = lmalloc(sizeof (ulwp_t) + tls_size);
1319 	if (data == NULL)
1320 		thr_panic("cannot allocate thread structure for main thread");
1321 	/* LINTED pointer cast may result in improper alignment */
1322 	self = (ulwp_t *)(data + tls_size);
1323 	init_hash_table[0].hash_bucket = self;
1324 
1325 	self->ul_sigmask = uc.uc_sigmask;
1326 	delete_reserved_signals(&self->ul_sigmask);
1327 	/*
1328 	 * Are the old and new sets different?
1329 	 * (This can happen if we are currently blocking SIGCANCEL.)
1330 	 * If so, we must explicitly set our signal mask, below.
1331 	 */
1332 	setmask =
1333 	    ((self->ul_sigmask.__sigbits[0] ^ uc.uc_sigmask.__sigbits[0]) |
1334 	    (self->ul_sigmask.__sigbits[1] ^ uc.uc_sigmask.__sigbits[1]) |
1335 	    (self->ul_sigmask.__sigbits[2] ^ uc.uc_sigmask.__sigbits[2]) |
1336 	    (self->ul_sigmask.__sigbits[3] ^ uc.uc_sigmask.__sigbits[3]));
1337 
1338 #ifdef __sparc
1339 	/*
1340 	 * We cache several instructions in the thread structure for use
1341 	 * by the fasttrap DTrace provider. When changing this, read the
1342 	 * comment in fasttrap.h for the all the other places that must
1343 	 * be changed.
1344 	 */
1345 	self->ul_dsave = 0x9de04000;	/* save %g1, %g0, %sp */
1346 	self->ul_drestore = 0x81e80000;	/* restore %g0, %g0, %g0 */
1347 	self->ul_dftret = 0x91d0203a;	/* ta 0x3a */
1348 	self->ul_dreturn = 0x81ca0000;	/* return %o0 */
1349 #endif
1350 
1351 	self->ul_stktop = (uintptr_t)uc.uc_stack.ss_sp + uc.uc_stack.ss_size;
1352 	(void) getrlimit(RLIMIT_STACK, &rl);
1353 	self->ul_stksiz = rl.rlim_cur;
1354 	self->ul_stk = (caddr_t)(self->ul_stktop - self->ul_stksiz);
1355 
1356 	self->ul_forw = self->ul_back = self;
1357 	self->ul_hash = NULL;
1358 	self->ul_ix = 0;
1359 	self->ul_lwpid = 1; /* _lwp_self() */
1360 	self->ul_main = 1;
1361 	self->ul_self = self;
1362 	self->ul_policy = -1;		/* initialize only when needed */
1363 	self->ul_pri = 0;
1364 	self->ul_cid = 0;
1365 	self->ul_rtclassid = -1;
1366 	self->ul_uberdata = udp;
1367 	if (oldself != NULL) {
1368 		int i;
1369 
1370 		ASSERT(primary_link_map);
1371 		ASSERT(oldself->ul_main == 1);
1372 		self->ul_stsd = oldself->ul_stsd;
1373 		for (i = 0; i < TSD_NFAST; i++)
1374 			self->ul_ftsd[i] = oldself->ul_ftsd[i];
1375 		self->ul_tls = oldself->ul_tls;
1376 		/*
1377 		 * Retrieve all pointers to uberdata allocated
1378 		 * while running on previous link maps.
1379 		 * We would like to do a structure assignment here, but
1380 		 * gcc turns structure assignments into calls to memcpy(),
1381 		 * a function exported from libc.  We can't call any such
1382 		 * external functions until we establish curthread, below,
1383 		 * so we just call our private version of memcpy().
1384 		 */
1385 		(void) memcpy(udp, oldself->ul_uberdata, sizeof (*udp));
1386 		/*
1387 		 * These items point to global data on the primary link map.
1388 		 */
1389 		udp->thr_hash_table = init_hash_table;
1390 		udp->sigacthandler = sigacthandler;
1391 		udp->tdb.tdb_events = tdb_events;
1392 		ASSERT(udp->nthreads == 1 && !udp->uberflags.uf_mt);
1393 		ASSERT(udp->lwp_stacks == NULL);
1394 		ASSERT(udp->ulwp_freelist == NULL);
1395 		ASSERT(udp->ulwp_replace_free == NULL);
1396 		ASSERT(udp->hash_size == 1);
1397 	}
1398 	udp->all_lwps = self;
1399 	udp->ulwp_one = self;
1400 	udp->pid = getpid();
1401 	udp->nthreads = 1;
1402 	/*
1403 	 * In every link map, tdb_bootstrap points to the same piece of
1404 	 * allocated memory.  When the primary link map is initialized,
1405 	 * the allocated memory is assigned a pointer to the one true
1406 	 * uberdata.  This allows libc_db to initialize itself regardless
1407 	 * of which instance of libc it finds in the address space.
1408 	 */
1409 	if (udp->tdb_bootstrap == NULL)
1410 		udp->tdb_bootstrap = lmalloc(sizeof (uberdata_t *));
1411 	__tdb_bootstrap = udp->tdb_bootstrap;
1412 	if (primary_link_map) {
1413 		self->ul_primarymap = 1;
1414 		udp->primary_map = 1;
1415 		*udp->tdb_bootstrap = udp;
1416 	}
1417 	/*
1418 	 * Cancellation can't happen until:
1419 	 *	pthread_cancel() is called
1420 	 * or:
1421 	 *	another thread is created
1422 	 * For now, as a single-threaded process, set the flag that tells
1423 	 * PROLOGUE/EPILOGUE (in scalls.c) that cancellation can't happen.
1424 	 */
1425 	self->ul_nocancel = 1;
1426 
1427 #if defined(__amd64)
1428 	(void) ___lwp_private(_LWP_SETPRIVATE, _LWP_FSBASE, self);
1429 #elif defined(__i386)
1430 	(void) ___lwp_private(_LWP_SETPRIVATE, _LWP_GSBASE, self);
1431 #endif	/* __i386 || __amd64 */
1432 	set_curthread(self);		/* redundant on i386 */
1433 	/*
1434 	 * Now curthread is established and it is safe to call any
1435 	 * function in libc except one that uses thread-local storage.
1436 	 */
1437 	self->ul_errnop = &errno;
1438 	if (oldself != NULL) {
1439 		/* tls_size was zero when oldself was allocated */
1440 		lfree(oldself, sizeof (ulwp_t));
1441 	}
1442 	ssp_init();
1443 	mutex_setup();
1444 	atfork_init();
1445 	signal_init();
1446 
1447 	/*
1448 	 * If the stack is unlimited, we set the size to zero to disable
1449 	 * stack checking.
1450 	 * XXX: Work harder here.  Get the stack size from /proc/self/rmap
1451 	 */
1452 	if (self->ul_stksiz == RLIM_INFINITY) {
1453 		self->ul_ustack.ss_sp = (void *)self->ul_stktop;
1454 		self->ul_ustack.ss_size = 0;
1455 	} else {
1456 		self->ul_ustack.ss_sp = self->ul_stk;
1457 		self->ul_ustack.ss_size = self->ul_stksiz;
1458 	}
1459 	self->ul_ustack.ss_flags = 0;
1460 	(void) setustack(&self->ul_ustack);
1461 
1462 	/*
1463 	 * Get the variables that affect thread behavior from the environment.
1464 	 */
1465 	set_thread_vars();
1466 	udp->uberflags.uf_thread_error_detection = (char)thread_error_detection;
1467 	udp->thread_stack_cache = thread_stack_cache;
1468 
1469 	/*
1470 	 * Make per-thread copies of global variables, for speed.
1471 	 */
1472 	self->ul_queue_fifo = (char)thread_queue_fifo;
1473 	self->ul_cond_wait_defer = (char)thread_cond_wait_defer;
1474 	self->ul_error_detection = (char)thread_error_detection;
1475 	self->ul_async_safe = (char)thread_async_safe;
1476 	self->ul_door_noreserve = (char)thread_door_noreserve;
1477 	self->ul_misaligned = (char)thread_locks_misaligned;
1478 	self->ul_max_spinners = (uint8_t)thread_max_spinners;
1479 	self->ul_adaptive_spin = thread_adaptive_spin;
1480 	self->ul_queue_spin = thread_queue_spin;
1481 
1482 #if defined(__sparc) && !defined(_LP64)
1483 	if (self->ul_misaligned) {
1484 		/*
1485 		 * Tell the kernel to fix up ldx/stx instructions that
1486 		 * refer to non-8-byte aligned data instead of giving
1487 		 * the process an alignment trap and generating SIGBUS.
1488 		 *
1489 		 * Programs compiled for 32-bit sparc with the Studio SS12
1490 		 * compiler get this done for them automatically (in _init()).
1491 		 * We do it here for the benefit of programs compiled with
1492 		 * other compilers, like gcc.
1493 		 *
1494 		 * This is necessary for the _THREAD_LOCKS_MISALIGNED=1
1495 		 * environment variable horrible hack to work.
1496 		 */
1497 		extern void _do_fix_align(void);
1498 		_do_fix_align();
1499 	}
1500 #endif
1501 
1502 	/*
1503 	 * When we have initialized the primary link map, inform
1504 	 * the dynamic linker about our interface functions.
1505 	 * Set up our pointer to the program name.
1506 	 */
1507 	if (self->ul_primarymap)
1508 		_ld_libc((void *)rtld_funcs);
1509 	init_progname();
1510 
1511 	/*
1512 	 * Defer signals until TLS constructors have been called.
1513 	 */
1514 	sigoff(self);
1515 	tls_setup();
1516 	sigon(self);
1517 	if (setmask)
1518 		(void) restore_signals(self);
1519 
1520 	/*
1521 	 * Make private copies of __xpg4 and __xpg6 so libc can test
1522 	 * them after this point without invoking the dynamic linker.
1523 	 */
1524 	libc__xpg4 = __xpg4;
1525 	libc__xpg6 = __xpg6;
1526 
1527 	init_sigev_thread();
1528 	init_aio();
1529 
1530 	/*
1531 	 * We need to reset __threaded dynamically at runtime, so that
1532 	 * __threaded can be bound to __threaded outside libc which may not
1533 	 * have initial value of 1 (without a copy relocation in a.out).
1534 	 */
1535 	__threaded = 1;
1536 }
1537 
1538 #pragma fini(libc_fini)
1539 void
libc_fini()1540 libc_fini()
1541 {
1542 	/*
1543 	 * If we are doing fini processing for the instance of libc
1544 	 * on the first alternate link map (this happens only when
1545 	 * the dynamic linker rejects a bad audit library), then clear
1546 	 * __curthread().  We abandon whatever memory was allocated by
1547 	 * lmalloc() while running on this alternate link-map but we
1548 	 * don't care (and can't find the memory in any case); we just
1549 	 * want to protect the application from this bad audit library.
1550 	 * No fini processing is done by libc in the normal case.
1551 	 */
1552 
1553 	uberdata_t *udp = curthread->ul_uberdata;
1554 
1555 	if (udp->primary_map == 0 && udp == &__uberdata)
1556 		set_curthread(NULL);
1557 }
1558 
1559 /*
1560  * finish_init is called when we are about to become multi-threaded,
1561  * that is, on the first call to thr_create().
1562  */
1563 void
finish_init()1564 finish_init()
1565 {
1566 	ulwp_t *self = curthread;
1567 	uberdata_t *udp = self->ul_uberdata;
1568 	thr_hash_table_t *htp;
1569 	void *data;
1570 	int i;
1571 
1572 	/*
1573 	 * No locks needed here; we are single-threaded on the first call.
1574 	 * We can be called only after the primary link map has been set up.
1575 	 */
1576 	ASSERT(self->ul_primarymap);
1577 	ASSERT(self == udp->ulwp_one);
1578 	ASSERT(!udp->uberflags.uf_mt);
1579 	ASSERT(udp->hash_size == 1);
1580 
1581 	/*
1582 	 * Initialize self->ul_policy, self->ul_cid, and self->ul_pri.
1583 	 */
1584 	update_sched(self);
1585 
1586 	/*
1587 	 * Allocate the queue_head array if not already allocated.
1588 	 */
1589 	if (udp->queue_head == NULL)
1590 		queue_alloc();
1591 
1592 	/*
1593 	 * Now allocate the thread hash table.
1594 	 */
1595 	if ((data = mmap(NULL, HASHTBLSZ * sizeof (thr_hash_table_t),
1596 	    PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, (off_t)0))
1597 	    == MAP_FAILED)
1598 		thr_panic("cannot allocate thread hash table");
1599 
1600 	udp->thr_hash_table = htp = (thr_hash_table_t *)data;
1601 	udp->hash_size = HASHTBLSZ;
1602 	udp->hash_mask = HASHTBLSZ - 1;
1603 
1604 	for (i = 0; i < HASHTBLSZ; i++, htp++) {
1605 		htp->hash_lock.mutex_flag = LOCK_INITED;
1606 		htp->hash_lock.mutex_magic = MUTEX_MAGIC;
1607 		htp->hash_cond.cond_magic = COND_MAGIC;
1608 	}
1609 	hash_in_unlocked(self, TIDHASH(self->ul_lwpid, udp), udp);
1610 
1611 	/*
1612 	 * Set up the SIGCANCEL handler for threads cancellation.
1613 	 */
1614 	setup_cancelsig(SIGCANCEL);
1615 
1616 	/*
1617 	 * Arrange to do special things on exit --
1618 	 * - collect queue statistics from all remaining active threads.
1619 	 * - dump queue statistics to stderr if _THREAD_QUEUE_DUMP is set.
1620 	 * - grab assert_lock to ensure that assertion failures
1621 	 *   and a core dump take precedence over _exit().
1622 	 * (Functions are called in the reverse order of their registration.)
1623 	 */
1624 	(void) _atexit(grab_assert_lock);
1625 #if defined(THREAD_DEBUG)
1626 	(void) _atexit(dump_queue_statistics);
1627 	(void) _atexit(collect_queue_statistics);
1628 #endif
1629 }
1630 
1631 /*
1632  * Used only by postfork1_child(), below.
1633  */
1634 static void
mark_dead_and_buried(ulwp_t * ulwp)1635 mark_dead_and_buried(ulwp_t *ulwp)
1636 {
1637 	ulwp->ul_dead = 1;
1638 	ulwp->ul_lwpid = (lwpid_t)(-1);
1639 	ulwp->ul_hash = NULL;
1640 	ulwp->ul_ix = -1;
1641 	ulwp->ul_schedctl = NULL;
1642 	ulwp->ul_schedctl_called = NULL;
1643 }
1644 
1645 /*
1646  * This is called from fork1() in the child.
1647  * Reset our data structures to reflect one lwp.
1648  */
1649 void
postfork1_child()1650 postfork1_child()
1651 {
1652 	ulwp_t *self = curthread;
1653 	uberdata_t *udp = self->ul_uberdata;
1654 	queue_head_t *qp;
1655 	ulwp_t *next;
1656 	ulwp_t *ulwp;
1657 	int i;
1658 
1659 	/* daemon threads shouldn't call fork1(), but oh well... */
1660 	self->ul_usropts &= ~THR_DAEMON;
1661 	udp->nthreads = 1;
1662 	udp->ndaemons = 0;
1663 	udp->uberflags.uf_mt = 0;
1664 	__libc_threaded = 0;
1665 	for (i = 0; i < udp->hash_size; i++)
1666 		udp->thr_hash_table[i].hash_bucket = NULL;
1667 	self->ul_lwpid = _lwp_self();
1668 	hash_in_unlocked(self, TIDHASH(self->ul_lwpid, udp), udp);
1669 
1670 	/*
1671 	 * Some thread in the parent might have been suspended
1672 	 * while holding udp->callout_lock or udp->ld_lock.
1673 	 * Reinitialize the child's copies.
1674 	 */
1675 	(void) mutex_init(&udp->callout_lock,
1676 	    USYNC_THREAD | LOCK_RECURSIVE, NULL);
1677 	(void) mutex_init(&udp->ld_lock,
1678 	    USYNC_THREAD | LOCK_RECURSIVE, NULL);
1679 
1680 	/* no one in the child is on a sleep queue; reinitialize */
1681 	if ((qp = udp->queue_head) != NULL) {
1682 		(void) memset(qp, 0, 2 * QHASHSIZE * sizeof (queue_head_t));
1683 		for (i = 0; i < 2 * QHASHSIZE; qp++, i++) {
1684 			qp->qh_type = (i < QHASHSIZE)? MX : CV;
1685 			qp->qh_lock.mutex_flag = LOCK_INITED;
1686 			qp->qh_lock.mutex_magic = MUTEX_MAGIC;
1687 			qp->qh_hlist = &qp->qh_def_root;
1688 #if defined(THREAD_DEBUG)
1689 			qp->qh_hlen = 1;
1690 			qp->qh_hmax = 1;
1691 #endif
1692 		}
1693 	}
1694 
1695 	/*
1696 	 * Do post-fork1 processing for subsystems that need it.
1697 	 * We need to do this before unmapping all of the abandoned
1698 	 * threads' stacks, below(), because the post-fork1 actions
1699 	 * might require access to those stacks.
1700 	 */
1701 	postfork1_child_sigev_aio();
1702 	postfork1_child_sigev_mq();
1703 	postfork1_child_sigev_timer();
1704 	postfork1_child_aio();
1705 	/*
1706 	 * The above subsystems use thread pools, so this action
1707 	 * must be performed after those actions.
1708 	 */
1709 	postfork1_child_tpool();
1710 
1711 	/*
1712 	 * All lwps except ourself are gone.  Mark them so.
1713 	 * First mark all of the lwps that have already been freed.
1714 	 * Then mark and free all of the active lwps except ourself.
1715 	 * Since we are single-threaded, no locks are required here.
1716 	 */
1717 	for (ulwp = udp->lwp_stacks; ulwp != NULL; ulwp = ulwp->ul_next)
1718 		mark_dead_and_buried(ulwp);
1719 	for (ulwp = udp->ulwp_freelist; ulwp != NULL; ulwp = ulwp->ul_next)
1720 		mark_dead_and_buried(ulwp);
1721 	for (ulwp = self->ul_forw; ulwp != self; ulwp = next) {
1722 		next = ulwp->ul_forw;
1723 		ulwp->ul_forw = ulwp->ul_back = NULL;
1724 		mark_dead_and_buried(ulwp);
1725 		tsd_free(ulwp);
1726 		tls_free(ulwp);
1727 		rwl_free(ulwp);
1728 		heldlock_free(ulwp);
1729 		ulwp_free(ulwp);
1730 	}
1731 	self->ul_forw = self->ul_back = udp->all_lwps = self;
1732 	if (self != udp->ulwp_one)
1733 		mark_dead_and_buried(udp->ulwp_one);
1734 	if ((ulwp = udp->all_zombies) != NULL) {
1735 		ASSERT(udp->nzombies != 0);
1736 		do {
1737 			next = ulwp->ul_forw;
1738 			ulwp->ul_forw = ulwp->ul_back = NULL;
1739 			mark_dead_and_buried(ulwp);
1740 			udp->nzombies--;
1741 			if (ulwp->ul_replace) {
1742 				ulwp->ul_next = NULL;
1743 				if (udp->ulwp_replace_free == NULL) {
1744 					udp->ulwp_replace_free =
1745 					    udp->ulwp_replace_last = ulwp;
1746 				} else {
1747 					udp->ulwp_replace_last->ul_next = ulwp;
1748 					udp->ulwp_replace_last = ulwp;
1749 				}
1750 			}
1751 		} while ((ulwp = next) != udp->all_zombies);
1752 		ASSERT(udp->nzombies == 0);
1753 		udp->all_zombies = NULL;
1754 		udp->nzombies = 0;
1755 	}
1756 	trim_stack_cache(0);
1757 }
1758 
1759 lwpid_t
lwp_self(void)1760 lwp_self(void)
1761 {
1762 	return (curthread->ul_lwpid);
1763 }
1764 
1765 #pragma weak _ti_thr_self = thr_self
1766 #pragma weak pthread_self = thr_self
1767 thread_t
thr_self()1768 thr_self()
1769 {
1770 	return (curthread->ul_lwpid);
1771 }
1772 
1773 int
thr_main()1774 thr_main()
1775 {
1776 	ulwp_t *self = __curthread();
1777 
1778 	return ((self == NULL)? -1 : self->ul_main);
1779 }
1780 
1781 int
_thrp_cancelled(void)1782 _thrp_cancelled(void)
1783 {
1784 	return (curthread->ul_rval == PTHREAD_CANCELED);
1785 }
1786 
1787 int
_thrp_stksegment(ulwp_t * ulwp,stack_t * stk)1788 _thrp_stksegment(ulwp_t *ulwp, stack_t *stk)
1789 {
1790 	stk->ss_sp = (void *)ulwp->ul_stktop;
1791 	stk->ss_size = ulwp->ul_stksiz;
1792 	stk->ss_flags = 0;
1793 	return (0);
1794 }
1795 
1796 #pragma weak _thr_stksegment = thr_stksegment
1797 int
thr_stksegment(stack_t * stk)1798 thr_stksegment(stack_t *stk)
1799 {
1800 	return (_thrp_stksegment(curthread, stk));
1801 }
1802 
1803 void
force_continue(ulwp_t * ulwp)1804 force_continue(ulwp_t *ulwp)
1805 {
1806 #if defined(THREAD_DEBUG)
1807 	ulwp_t *self = curthread;
1808 	uberdata_t *udp = self->ul_uberdata;
1809 #endif
1810 	int error;
1811 	timespec_t ts;
1812 
1813 	ASSERT(MUTEX_OWNED(&udp->fork_lock, self));
1814 	ASSERT(MUTEX_OWNED(ulwp_mutex(ulwp, udp), self));
1815 
1816 	for (;;) {
1817 		error = _lwp_continue(ulwp->ul_lwpid);
1818 		if (error != 0 && error != EINTR)
1819 			break;
1820 		error = 0;
1821 		if (ulwp->ul_stopping) {	/* it is stopping itself */
1822 			ts.tv_sec = 0;		/* give it a chance to run */
1823 			ts.tv_nsec = 100000;	/* 100 usecs or clock tick */
1824 			(void) __nanosleep(&ts, NULL);
1825 		}
1826 		if (!ulwp->ul_stopping)		/* it is running now */
1827 			break;			/* so we are done */
1828 		/*
1829 		 * It is marked as being in the process of stopping
1830 		 * itself.  Loop around and continue it again.
1831 		 * It may not have been stopped the first time.
1832 		 */
1833 	}
1834 }
1835 
1836 /*
1837  * Suspend an lwp with lwp_suspend(), then move it to a safe point,
1838  * that is, to a point where ul_critical and ul_rtld are both zero.
1839  * On return, the ulwp_lock() is dropped as with ulwp_unlock().
1840  * If 'link_dropped' is non-NULL, then 'link_lock' is held on entry.
1841  * If we have to drop link_lock, we store 1 through link_dropped.
1842  * If the lwp exits before it can be suspended, we return ESRCH.
1843  */
1844 int
safe_suspend(ulwp_t * ulwp,uchar_t whystopped,int * link_dropped)1845 safe_suspend(ulwp_t *ulwp, uchar_t whystopped, int *link_dropped)
1846 {
1847 	ulwp_t *self = curthread;
1848 	uberdata_t *udp = self->ul_uberdata;
1849 	cond_t *cvp = ulwp_condvar(ulwp, udp);
1850 	mutex_t *mp = ulwp_mutex(ulwp, udp);
1851 	thread_t tid = ulwp->ul_lwpid;
1852 	int ix = ulwp->ul_ix;
1853 	int error = 0;
1854 
1855 	ASSERT(whystopped == TSTP_REGULAR ||
1856 	    whystopped == TSTP_MUTATOR ||
1857 	    whystopped == TSTP_FORK);
1858 	ASSERT(ulwp != self);
1859 	ASSERT(!ulwp->ul_stop);
1860 	ASSERT(MUTEX_OWNED(&udp->fork_lock, self));
1861 	ASSERT(MUTEX_OWNED(mp, self));
1862 
1863 	if (link_dropped != NULL)
1864 		*link_dropped = 0;
1865 
1866 	/*
1867 	 * We must grab the target's spin lock before suspending it.
1868 	 * See the comments below and in _thrp_suspend() for why.
1869 	 */
1870 	spin_lock_set(&ulwp->ul_spinlock);
1871 	(void) ___lwp_suspend(tid);
1872 	spin_lock_clear(&ulwp->ul_spinlock);
1873 
1874 top:
1875 	if ((ulwp->ul_critical == 0 && ulwp->ul_rtld == 0) ||
1876 	    ulwp->ul_stopping) {
1877 		/* thread is already safe */
1878 		ulwp->ul_stop |= whystopped;
1879 	} else {
1880 		/*
1881 		 * Setting ul_pleasestop causes the target thread to stop
1882 		 * itself in _thrp_suspend(), below, after we drop its lock.
1883 		 * We must continue the critical thread before dropping
1884 		 * link_lock because the critical thread may be holding
1885 		 * the queue lock for link_lock.  This is delicate.
1886 		 */
1887 		ulwp->ul_pleasestop |= whystopped;
1888 		force_continue(ulwp);
1889 		if (link_dropped != NULL) {
1890 			*link_dropped = 1;
1891 			lmutex_unlock(&udp->link_lock);
1892 			/* be sure to drop link_lock only once */
1893 			link_dropped = NULL;
1894 		}
1895 
1896 		/*
1897 		 * The thread may disappear by calling thr_exit() so we
1898 		 * cannot rely on the ulwp pointer after dropping the lock.
1899 		 * Instead, we search the hash table to find it again.
1900 		 * When we return, we may find that the thread has been
1901 		 * continued by some other thread.  The suspend/continue
1902 		 * interfaces are prone to such race conditions by design.
1903 		 */
1904 		while (ulwp && !ulwp->ul_dead && !ulwp->ul_stop &&
1905 		    (ulwp->ul_pleasestop & whystopped)) {
1906 			(void) __cond_wait(cvp, mp);
1907 			for (ulwp = udp->thr_hash_table[ix].hash_bucket;
1908 			    ulwp != NULL; ulwp = ulwp->ul_hash) {
1909 				if (ulwp->ul_lwpid == tid)
1910 					break;
1911 			}
1912 		}
1913 
1914 		if (ulwp == NULL || ulwp->ul_dead)
1915 			error = ESRCH;
1916 		else {
1917 			/*
1918 			 * Do another lwp_suspend() to make sure we don't
1919 			 * return until the target thread is fully stopped
1920 			 * in the kernel.  Don't apply lwp_suspend() until
1921 			 * we know that the target is not holding any
1922 			 * queue locks, that is, that it has completed
1923 			 * ulwp_unlock(self) and has, or at least is
1924 			 * about to, call lwp_suspend() on itself.  We do
1925 			 * this by grabbing the target's spin lock.
1926 			 */
1927 			ASSERT(ulwp->ul_lwpid == tid);
1928 			spin_lock_set(&ulwp->ul_spinlock);
1929 			(void) ___lwp_suspend(tid);
1930 			spin_lock_clear(&ulwp->ul_spinlock);
1931 			/*
1932 			 * If some other thread did a thr_continue()
1933 			 * on the target thread we have to start over.
1934 			 */
1935 			if (!ulwp->ul_stopping || !(ulwp->ul_stop & whystopped))
1936 				goto top;
1937 		}
1938 	}
1939 
1940 	(void) cond_broadcast(cvp);
1941 	lmutex_unlock(mp);
1942 	return (error);
1943 }
1944 
1945 int
_thrp_suspend(thread_t tid,uchar_t whystopped)1946 _thrp_suspend(thread_t tid, uchar_t whystopped)
1947 {
1948 	ulwp_t *self = curthread;
1949 	uberdata_t *udp = self->ul_uberdata;
1950 	ulwp_t *ulwp;
1951 	int error = 0;
1952 
1953 	ASSERT((whystopped & (TSTP_REGULAR|TSTP_MUTATOR|TSTP_FORK)) != 0);
1954 	ASSERT((whystopped & ~(TSTP_REGULAR|TSTP_MUTATOR|TSTP_FORK)) == 0);
1955 
1956 	/*
1957 	 * We can't suspend anyone except ourself while
1958 	 * some other thread is performing a fork.
1959 	 * This also allows only one suspension at a time.
1960 	 */
1961 	if (tid != self->ul_lwpid)
1962 		fork_lock_enter();
1963 
1964 	if ((ulwp = find_lwp(tid)) == NULL)
1965 		error = ESRCH;
1966 	else if (whystopped == TSTP_MUTATOR && !ulwp->ul_mutator) {
1967 		ulwp_unlock(ulwp, udp);
1968 		error = EINVAL;
1969 	} else if (ulwp->ul_stop) {	/* already stopped */
1970 		ulwp->ul_stop |= whystopped;
1971 		ulwp_broadcast(ulwp);
1972 		ulwp_unlock(ulwp, udp);
1973 	} else if (ulwp != self) {
1974 		/*
1975 		 * After suspending the other thread, move it out of a
1976 		 * critical section and deal with the schedctl mappings.
1977 		 * safe_suspend() suspends the other thread, calls
1978 		 * ulwp_broadcast(ulwp) and drops the ulwp lock.
1979 		 */
1980 		error = safe_suspend(ulwp, whystopped, NULL);
1981 	} else {
1982 		int schedctl_after_fork = 0;
1983 
1984 		/*
1985 		 * We are suspending ourself.  We must not take a signal
1986 		 * until we return from lwp_suspend() and clear ul_stopping.
1987 		 * This is to guard against siglongjmp().
1988 		 */
1989 		enter_critical(self);
1990 		self->ul_sp = stkptr();
1991 		_flush_windows();	/* sparc */
1992 		self->ul_pleasestop = 0;
1993 		self->ul_stop |= whystopped;
1994 		/*
1995 		 * Grab our spin lock before dropping ulwp_mutex(self).
1996 		 * This prevents the suspending thread from applying
1997 		 * lwp_suspend() to us before we emerge from
1998 		 * lmutex_unlock(mp) and have dropped mp's queue lock.
1999 		 */
2000 		spin_lock_set(&self->ul_spinlock);
2001 		self->ul_stopping = 1;
2002 		ulwp_broadcast(self);
2003 		ulwp_unlock(self, udp);
2004 		/*
2005 		 * From this point until we return from lwp_suspend(),
2006 		 * we must not call any function that might invoke the
2007 		 * dynamic linker, that is, we can only call functions
2008 		 * private to the library.
2009 		 *
2010 		 * Also, this is a nasty race condition for a process
2011 		 * that is undergoing a forkall() operation:
2012 		 * Once we clear our spinlock (below), we are vulnerable
2013 		 * to being suspended by the forkall() thread before
2014 		 * we manage to suspend ourself in ___lwp_suspend().
2015 		 * See safe_suspend() and force_continue().
2016 		 *
2017 		 * To avoid a SIGSEGV due to the disappearance
2018 		 * of the schedctl mappings in the child process,
2019 		 * which can happen in spin_lock_clear() if we
2020 		 * are suspended while we are in the middle of
2021 		 * its call to preempt(), we preemptively clear
2022 		 * our own schedctl pointer before dropping our
2023 		 * spinlock.  We reinstate it, in both the parent
2024 		 * and (if this really is a forkall()) the child.
2025 		 */
2026 		if (whystopped & TSTP_FORK) {
2027 			schedctl_after_fork = 1;
2028 			self->ul_schedctl = NULL;
2029 			self->ul_schedctl_called = &udp->uberflags;
2030 		}
2031 		spin_lock_clear(&self->ul_spinlock);
2032 		(void) ___lwp_suspend(tid);
2033 		/*
2034 		 * Somebody else continued us.
2035 		 * We can't grab ulwp_lock(self)
2036 		 * until after clearing ul_stopping.
2037 		 * force_continue() relies on this.
2038 		 */
2039 		self->ul_stopping = 0;
2040 		self->ul_sp = 0;
2041 		if (schedctl_after_fork) {
2042 			self->ul_schedctl_called = NULL;
2043 			self->ul_schedctl = NULL;
2044 			(void) setup_schedctl();
2045 		}
2046 		ulwp_lock(self, udp);
2047 		ulwp_broadcast(self);
2048 		ulwp_unlock(self, udp);
2049 		exit_critical(self);
2050 	}
2051 
2052 	if (tid != self->ul_lwpid)
2053 		fork_lock_exit();
2054 
2055 	return (error);
2056 }
2057 
2058 /*
2059  * Suspend all lwps other than ourself in preparation for fork.
2060  */
2061 void
suspend_fork()2062 suspend_fork()
2063 {
2064 	ulwp_t *self = curthread;
2065 	uberdata_t *udp = self->ul_uberdata;
2066 	ulwp_t *ulwp;
2067 	int link_dropped;
2068 
2069 	ASSERT(MUTEX_OWNED(&udp->fork_lock, self));
2070 top:
2071 	lmutex_lock(&udp->link_lock);
2072 
2073 	for (ulwp = self->ul_forw; ulwp != self; ulwp = ulwp->ul_forw) {
2074 		ulwp_lock(ulwp, udp);
2075 		if (ulwp->ul_stop) {	/* already stopped */
2076 			ulwp->ul_stop |= TSTP_FORK;
2077 			ulwp_broadcast(ulwp);
2078 			ulwp_unlock(ulwp, udp);
2079 		} else {
2080 			/*
2081 			 * Move the stopped lwp out of a critical section.
2082 			 */
2083 			if (safe_suspend(ulwp, TSTP_FORK, &link_dropped) ||
2084 			    link_dropped)
2085 				goto top;
2086 		}
2087 	}
2088 
2089 	lmutex_unlock(&udp->link_lock);
2090 }
2091 
2092 void
continue_fork(int child)2093 continue_fork(int child)
2094 {
2095 	ulwp_t *self = curthread;
2096 	uberdata_t *udp = self->ul_uberdata;
2097 	ulwp_t *ulwp;
2098 
2099 	ASSERT(MUTEX_OWNED(&udp->fork_lock, self));
2100 
2101 	/*
2102 	 * Clear the schedctl pointers in the child of forkall().
2103 	 */
2104 	if (child) {
2105 		for (ulwp = self->ul_forw; ulwp != self; ulwp = ulwp->ul_forw) {
2106 			ulwp->ul_schedctl_called =
2107 			    ulwp->ul_dead? &udp->uberflags : NULL;
2108 			ulwp->ul_schedctl = NULL;
2109 		}
2110 	}
2111 
2112 	/*
2113 	 * Set all lwps that were stopped for fork() running again.
2114 	 */
2115 	lmutex_lock(&udp->link_lock);
2116 	for (ulwp = self->ul_forw; ulwp != self; ulwp = ulwp->ul_forw) {
2117 		mutex_t *mp = ulwp_mutex(ulwp, udp);
2118 		lmutex_lock(mp);
2119 		ASSERT(ulwp->ul_stop & TSTP_FORK);
2120 		ulwp->ul_stop &= ~TSTP_FORK;
2121 		ulwp_broadcast(ulwp);
2122 		if (!ulwp->ul_stop)
2123 			force_continue(ulwp);
2124 		lmutex_unlock(mp);
2125 	}
2126 	lmutex_unlock(&udp->link_lock);
2127 }
2128 
2129 int
_thrp_continue(thread_t tid,uchar_t whystopped)2130 _thrp_continue(thread_t tid, uchar_t whystopped)
2131 {
2132 	uberdata_t *udp = curthread->ul_uberdata;
2133 	ulwp_t *ulwp;
2134 	mutex_t *mp;
2135 	int error = 0;
2136 
2137 	ASSERT(whystopped == TSTP_REGULAR ||
2138 	    whystopped == TSTP_MUTATOR);
2139 
2140 	/*
2141 	 * We single-thread the entire thread suspend/continue mechanism.
2142 	 */
2143 	fork_lock_enter();
2144 
2145 	if ((ulwp = find_lwp(tid)) == NULL) {
2146 		fork_lock_exit();
2147 		return (ESRCH);
2148 	}
2149 
2150 	mp = ulwp_mutex(ulwp, udp);
2151 	if ((whystopped == TSTP_MUTATOR && !ulwp->ul_mutator)) {
2152 		error = EINVAL;
2153 	} else if (ulwp->ul_stop & whystopped) {
2154 		ulwp->ul_stop &= ~whystopped;
2155 		ulwp_broadcast(ulwp);
2156 		if (!ulwp->ul_stop) {
2157 			if (whystopped == TSTP_REGULAR && ulwp->ul_created) {
2158 				ulwp->ul_sp = 0;
2159 				ulwp->ul_created = 0;
2160 			}
2161 			force_continue(ulwp);
2162 		}
2163 	}
2164 	lmutex_unlock(mp);
2165 
2166 	fork_lock_exit();
2167 	return (error);
2168 }
2169 
2170 int
thr_suspend(thread_t tid)2171 thr_suspend(thread_t tid)
2172 {
2173 	return (_thrp_suspend(tid, TSTP_REGULAR));
2174 }
2175 
2176 int
thr_continue(thread_t tid)2177 thr_continue(thread_t tid)
2178 {
2179 	return (_thrp_continue(tid, TSTP_REGULAR));
2180 }
2181 
2182 void
thr_yield()2183 thr_yield()
2184 {
2185 	yield();
2186 }
2187 
2188 #pragma weak pthread_kill = thr_kill
2189 #pragma weak _thr_kill = thr_kill
2190 int
thr_kill(thread_t tid,int sig)2191 thr_kill(thread_t tid, int sig)
2192 {
2193 	if (sig == SIGCANCEL)
2194 		return (EINVAL);
2195 	return (_lwp_kill(tid, sig));
2196 }
2197 
2198 /*
2199  * Exit a critical section, take deferred actions if necessary.
2200  * Called from exit_critical() and from sigon().
2201  */
2202 void
do_exit_critical()2203 do_exit_critical()
2204 {
2205 	ulwp_t *self = curthread;
2206 	int sig;
2207 
2208 	ASSERT(self->ul_critical == 0);
2209 
2210 	/*
2211 	 * Don't suspend ourself or take a deferred signal while dying
2212 	 * or while executing inside the dynamic linker (ld.so.1).
2213 	 */
2214 	if (self->ul_dead || self->ul_rtld)
2215 		return;
2216 
2217 	while (self->ul_pleasestop ||
2218 	    (self->ul_cursig != 0 && self->ul_sigdefer == 0)) {
2219 		/*
2220 		 * Avoid a recursive call to exit_critical() in _thrp_suspend()
2221 		 * by keeping self->ul_critical == 1 here.
2222 		 */
2223 		self->ul_critical++;
2224 		while (self->ul_pleasestop) {
2225 			/*
2226 			 * Guard against suspending ourself while on a sleep
2227 			 * queue.  See the comments in call_user_handler().
2228 			 */
2229 			unsleep_self();
2230 			set_parking_flag(self, 0);
2231 			(void) _thrp_suspend(self->ul_lwpid,
2232 			    self->ul_pleasestop);
2233 		}
2234 		self->ul_critical--;
2235 
2236 		if ((sig = self->ul_cursig) != 0 && self->ul_sigdefer == 0) {
2237 			/*
2238 			 * Clear ul_cursig before proceeding.
2239 			 * This protects us from the dynamic linker's
2240 			 * calls to bind_guard()/bind_clear() in the
2241 			 * event that it is invoked to resolve a symbol
2242 			 * like take_deferred_signal() below.
2243 			 */
2244 			self->ul_cursig = 0;
2245 			take_deferred_signal(sig);
2246 			ASSERT(self->ul_cursig == 0);
2247 		}
2248 	}
2249 	ASSERT(self->ul_critical == 0);
2250 }
2251 
2252 /*
2253  * _ti_bind_guard() and _ti_bind_clear() are called by the dynamic linker
2254  * (ld.so.1) when it has do do something, like resolve a symbol to be called
2255  * by the application or one of its libraries.  _ti_bind_guard() is called
2256  * on entry to ld.so.1, _ti_bind_clear() on exit from ld.so.1 back to the
2257  * application.  The dynamic linker gets special dispensation from libc to
2258  * run in a critical region (all signals deferred and no thread suspension
2259  * or forking allowed), and to be immune from cancellation for the duration.
2260  */
2261 int
_ti_bind_guard(int flags)2262 _ti_bind_guard(int flags)
2263 {
2264 	ulwp_t *self = curthread;
2265 	uberdata_t *udp = self->ul_uberdata;
2266 	int bindflag = (flags & THR_FLG_RTLD);
2267 
2268 	if ((self->ul_bindflags & bindflag) == bindflag)
2269 		return (0);
2270 	self->ul_bindflags |= bindflag;
2271 	if ((flags & (THR_FLG_NOLOCK | THR_FLG_REENTER)) == THR_FLG_NOLOCK) {
2272 		sigoff(self);	/* see no signals while holding ld_lock */
2273 		self->ul_rtld++;	/* don't suspend while in ld.so.1 */
2274 		(void) mutex_lock(&udp->ld_lock);
2275 	}
2276 	enter_critical(self);
2277 	self->ul_save_state = self->ul_cancel_disabled;
2278 	self->ul_cancel_disabled = 1;
2279 	set_cancel_pending_flag(self, 0);
2280 	return (1);
2281 }
2282 
2283 int
_ti_bind_clear(int flags)2284 _ti_bind_clear(int flags)
2285 {
2286 	ulwp_t *self = curthread;
2287 	uberdata_t *udp = self->ul_uberdata;
2288 	int bindflag = (flags & THR_FLG_RTLD);
2289 
2290 	if ((self->ul_bindflags & bindflag) == 0)
2291 		return (self->ul_bindflags);
2292 	self->ul_bindflags &= ~bindflag;
2293 	self->ul_cancel_disabled = self->ul_save_state;
2294 	set_cancel_pending_flag(self, 0);
2295 	exit_critical(self);
2296 	if ((flags & (THR_FLG_NOLOCK | THR_FLG_REENTER)) == THR_FLG_NOLOCK) {
2297 		if (MUTEX_OWNED(&udp->ld_lock, self)) {
2298 			(void) mutex_unlock(&udp->ld_lock);
2299 			self->ul_rtld--;
2300 			sigon(self);	/* reenable signals */
2301 		}
2302 	}
2303 	return (self->ul_bindflags);
2304 }
2305 
2306 /*
2307  * Tell the dynamic linker (ld.so.1) whether or not it was entered from
2308  * a critical region in libc.  Return zero if not, else return non-zero.
2309  */
2310 int
_ti_critical(void)2311 _ti_critical(void)
2312 {
2313 	ulwp_t *self = curthread;
2314 	int level = self->ul_critical;
2315 
2316 	if ((self->ul_bindflags & THR_FLG_RTLD) == 0 || level == 0)
2317 		return (level);	/* ld.so.1 hasn't (yet) called enter() */
2318 	return (level - 1);
2319 }
2320 
2321 /*
2322  * sigoff() and sigon() enable cond_wait() to behave (optionally) like
2323  * it does in the old libthread (see the comments in cond_wait_queue()).
2324  * Also, signals are deferred at thread startup until TLS constructors
2325  * have all been called, at which time _thrp_setup() calls sigon().
2326  *
2327  * _sigoff() and _sigon() are external consolidation-private interfaces to
2328  * sigoff() and sigon(), respectively, in libc.  These are used in libnsl.
2329  * Also, _sigoff() and _sigon() are called from dbx's run-time checking
2330  * (librtc.so) to defer signals during its critical sections (not to be
2331  * confused with libc critical sections [see exit_critical() above]).
2332  */
2333 void
_sigoff(void)2334 _sigoff(void)
2335 {
2336 	ulwp_t *self = curthread;
2337 
2338 	sigoff(self);
2339 }
2340 
2341 void
_sigon(void)2342 _sigon(void)
2343 {
2344 	ulwp_t *self = curthread;
2345 
2346 	ASSERT(self->ul_sigdefer > 0);
2347 	sigon(self);
2348 }
2349 
2350 int
thr_getconcurrency()2351 thr_getconcurrency()
2352 {
2353 	return (thr_concurrency);
2354 }
2355 
2356 int
pthread_getconcurrency()2357 pthread_getconcurrency()
2358 {
2359 	return (pthread_concurrency);
2360 }
2361 
2362 int
thr_setconcurrency(int new_level)2363 thr_setconcurrency(int new_level)
2364 {
2365 	uberdata_t *udp = curthread->ul_uberdata;
2366 
2367 	if (new_level < 0)
2368 		return (EINVAL);
2369 	if (new_level > 65536)		/* 65536 is totally arbitrary */
2370 		return (EAGAIN);
2371 	lmutex_lock(&udp->link_lock);
2372 	if (new_level > thr_concurrency)
2373 		thr_concurrency = new_level;
2374 	lmutex_unlock(&udp->link_lock);
2375 	return (0);
2376 }
2377 
2378 int
pthread_setconcurrency(int new_level)2379 pthread_setconcurrency(int new_level)
2380 {
2381 	if (new_level < 0)
2382 		return (EINVAL);
2383 	if (new_level > 65536)		/* 65536 is totally arbitrary */
2384 		return (EAGAIN);
2385 	pthread_concurrency = new_level;
2386 	return (0);
2387 }
2388 
2389 size_t
thr_min_stack(void)2390 thr_min_stack(void)
2391 {
2392 	return (MINSTACK);
2393 }
2394 
2395 int
__nthreads(void)2396 __nthreads(void)
2397 {
2398 	return (curthread->ul_uberdata->nthreads);
2399 }
2400 
2401 /* "/proc/self/lwp/%u/lwpname" w/o stdio */
2402 static void
lwpname_path(pthread_t tid,char * buf,size_t bufsize)2403 lwpname_path(pthread_t tid, char *buf, size_t bufsize)
2404 {
2405 	(void) strlcpy(buf, "/proc/self/lwp/", bufsize);
2406 	ultos((uint64_t)tid, 10, buf + strlen(buf));
2407 	(void) strlcat(buf, "/lwpname", bufsize);
2408 }
2409 
2410 #pragma weak pthread_setname_np = thr_setname
2411 int
thr_setname(pthread_t tid,const char * name)2412 thr_setname(pthread_t tid, const char *name)
2413 {
2414 	extern ssize_t __write(int, const void *, size_t);
2415 	char path[PATH_MAX];
2416 	int saved_errno;
2417 	size_t len;
2418 	ssize_t n;
2419 	int fd;
2420 
2421 	if (name == NULL)
2422 		name = "";
2423 
2424 	len = strlen(name) + 1;
2425 	if (len > THREAD_NAME_MAX)
2426 		return (ERANGE);
2427 
2428 	lwpname_path(tid, path, sizeof (path));
2429 
2430 	if ((fd = __open(path, O_WRONLY, 0)) < 0) {
2431 		if (errno == ENOENT)
2432 			errno = ESRCH;
2433 		return (errno);
2434 	}
2435 
2436 	n = __write(fd, name, len);
2437 	saved_errno = errno;
2438 	(void) __close(fd);
2439 
2440 	if (n < 0)
2441 		return (saved_errno);
2442 	if (n != len)
2443 		return (EFAULT);
2444 	return (0);
2445 }
2446 
2447 #pragma weak pthread_getname_np = thr_getname
2448 int
thr_getname(pthread_t tid,char * buf,size_t bufsize)2449 thr_getname(pthread_t tid, char *buf, size_t bufsize)
2450 {
2451 	extern ssize_t __read(int, void *, size_t);
2452 	char name[THREAD_NAME_MAX];
2453 	char path[PATH_MAX];
2454 	int saved_errno;
2455 	ssize_t n;
2456 	int fd;
2457 
2458 	if (buf == NULL)
2459 		return (EINVAL);
2460 
2461 	lwpname_path(tid, path, sizeof (path));
2462 
2463 	if ((fd = __open(path, O_RDONLY, 0)) < 0) {
2464 		if (errno == ENOENT)
2465 			errno = ESRCH;
2466 		return (errno);
2467 	}
2468 
2469 	n = __read(fd, name, sizeof (name));
2470 	saved_errno = errno;
2471 	(void) __close(fd);
2472 
2473 	if (n < 0)
2474 		return (saved_errno);
2475 	if (n != sizeof (name))
2476 		return (EFAULT);
2477 	if (strlcpy(buf, name, bufsize) >= bufsize)
2478 		return (ERANGE);
2479 	return (0);
2480 }
2481 
2482 /*
2483  * XXX
2484  * The remainder of this file implements the private interfaces to java for
2485  * garbage collection.  It is no longer used, at least by java 1.2.
2486  * It can all go away once all old JVMs have disappeared.
2487  */
2488 
2489 int	suspendingallmutators;	/* when non-zero, suspending all mutators. */
2490 int	suspendedallmutators;	/* when non-zero, all mutators suspended. */
2491 int	mutatorsbarrier;	/* when non-zero, mutators barrier imposed. */
2492 mutex_t	mutatorslock = DEFAULTMUTEX;	/* used to enforce mutators barrier. */
2493 cond_t	mutatorscv = DEFAULTCV;		/* where non-mutators sleep. */
2494 
2495 /*
2496  * Get the available register state for the target thread.
2497  * Return non-volatile registers: TRS_NONVOLATILE
2498  */
2499 #pragma weak _thr_getstate = thr_getstate
2500 int
thr_getstate(thread_t tid,int * flag,lwpid_t * lwp,stack_t * ss,gregset_t rs)2501 thr_getstate(thread_t tid, int *flag, lwpid_t *lwp, stack_t *ss, gregset_t rs)
2502 {
2503 	ulwp_t *self = curthread;
2504 	uberdata_t *udp = self->ul_uberdata;
2505 	ulwp_t **ulwpp;
2506 	ulwp_t *ulwp;
2507 	int error = 0;
2508 	int trs_flag = TRS_LWPID;
2509 
2510 	if (tid == 0 || self->ul_lwpid == tid) {
2511 		ulwp = self;
2512 		ulwp_lock(ulwp, udp);
2513 	} else if ((ulwpp = find_lwpp(tid)) != NULL) {
2514 		ulwp = *ulwpp;
2515 	} else {
2516 		if (flag)
2517 			*flag = TRS_INVALID;
2518 		return (ESRCH);
2519 	}
2520 
2521 	if (ulwp->ul_dead) {
2522 		trs_flag = TRS_INVALID;
2523 	} else if (!ulwp->ul_stop && !suspendedallmutators) {
2524 		error = EINVAL;
2525 		trs_flag = TRS_INVALID;
2526 	} else if (ulwp->ul_stop) {
2527 		trs_flag = TRS_NONVOLATILE;
2528 		getgregs(ulwp, rs);
2529 	}
2530 
2531 	if (flag)
2532 		*flag = trs_flag;
2533 	if (lwp)
2534 		*lwp = tid;
2535 	if (ss != NULL)
2536 		(void) _thrp_stksegment(ulwp, ss);
2537 
2538 	ulwp_unlock(ulwp, udp);
2539 	return (error);
2540 }
2541 
2542 /*
2543  * Set the appropriate register state for the target thread.
2544  * This is not used by java.  It exists solely for the MSTC test suite.
2545  */
2546 #pragma weak _thr_setstate = thr_setstate
2547 int
thr_setstate(thread_t tid,int flag,gregset_t rs)2548 thr_setstate(thread_t tid, int flag, gregset_t rs)
2549 {
2550 	uberdata_t *udp = curthread->ul_uberdata;
2551 	ulwp_t *ulwp;
2552 	int error = 0;
2553 
2554 	if ((ulwp = find_lwp(tid)) == NULL)
2555 		return (ESRCH);
2556 
2557 	if (!ulwp->ul_stop && !suspendedallmutators)
2558 		error = EINVAL;
2559 	else if (rs != NULL) {
2560 		switch (flag) {
2561 		case TRS_NONVOLATILE:
2562 			/* do /proc stuff here? */
2563 			if (ulwp->ul_stop)
2564 				setgregs(ulwp, rs);
2565 			else
2566 				error = EINVAL;
2567 			break;
2568 		case TRS_LWPID:		/* do /proc stuff here? */
2569 		default:
2570 			error = EINVAL;
2571 			break;
2572 		}
2573 	}
2574 
2575 	ulwp_unlock(ulwp, udp);
2576 	return (error);
2577 }
2578 
2579 int
getlwpstatus(thread_t tid,struct lwpstatus * sp)2580 getlwpstatus(thread_t tid, struct lwpstatus *sp)
2581 {
2582 	extern ssize_t __pread(int, void *, size_t, off_t);
2583 	char buf[100];
2584 	int fd;
2585 
2586 	/* "/proc/self/lwp/%u/lwpstatus" w/o stdio */
2587 	(void) strcpy(buf, "/proc/self/lwp/");
2588 	ultos((uint64_t)tid, 10, buf + strlen(buf));
2589 	(void) strcat(buf, "/lwpstatus");
2590 	if ((fd = __open(buf, O_RDONLY, 0)) >= 0) {
2591 		while (__pread(fd, sp, sizeof (*sp), 0) == sizeof (*sp)) {
2592 			if (sp->pr_flags & PR_STOPPED) {
2593 				(void) __close(fd);
2594 				return (0);
2595 			}
2596 			yield();	/* give it a chance to stop */
2597 		}
2598 		(void) __close(fd);
2599 	}
2600 	return (-1);
2601 }
2602 
2603 int
putlwpregs(thread_t tid,prgregset_t prp)2604 putlwpregs(thread_t tid, prgregset_t prp)
2605 {
2606 	extern ssize_t __writev(int, const struct iovec *, int);
2607 	char buf[100];
2608 	int fd;
2609 	long dstop_sreg[2];
2610 	long run_null[2];
2611 	iovec_t iov[3];
2612 
2613 	/* "/proc/self/lwp/%u/lwpctl" w/o stdio */
2614 	(void) strcpy(buf, "/proc/self/lwp/");
2615 	ultos((uint64_t)tid, 10, buf + strlen(buf));
2616 	(void) strcat(buf, "/lwpctl");
2617 	if ((fd = __open(buf, O_WRONLY, 0)) >= 0) {
2618 		dstop_sreg[0] = PCDSTOP;	/* direct it to stop */
2619 		dstop_sreg[1] = PCSREG;		/* set the registers */
2620 		iov[0].iov_base = (caddr_t)dstop_sreg;
2621 		iov[0].iov_len = sizeof (dstop_sreg);
2622 		iov[1].iov_base = (caddr_t)prp;	/* from the register set */
2623 		iov[1].iov_len = sizeof (prgregset_t);
2624 		run_null[0] = PCRUN;		/* make it runnable again */
2625 		run_null[1] = 0;
2626 		iov[2].iov_base = (caddr_t)run_null;
2627 		iov[2].iov_len = sizeof (run_null);
2628 		if (__writev(fd, iov, 3) >= 0) {
2629 			(void) __close(fd);
2630 			return (0);
2631 		}
2632 		(void) __close(fd);
2633 	}
2634 	return (-1);
2635 }
2636 
2637 static ulong_t
gettsp_slow(thread_t tid)2638 gettsp_slow(thread_t tid)
2639 {
2640 	char buf[100];
2641 	struct lwpstatus status;
2642 
2643 	if (getlwpstatus(tid, &status) != 0) {
2644 		/* "__gettsp(%u): can't read lwpstatus" w/o stdio */
2645 		(void) strcpy(buf, "__gettsp(");
2646 		ultos((uint64_t)tid, 10, buf + strlen(buf));
2647 		(void) strcat(buf, "): can't read lwpstatus");
2648 		thr_panic(buf);
2649 	}
2650 	return (status.pr_reg[R_SP]);
2651 }
2652 
2653 ulong_t
__gettsp(thread_t tid)2654 __gettsp(thread_t tid)
2655 {
2656 	uberdata_t *udp = curthread->ul_uberdata;
2657 	ulwp_t *ulwp;
2658 	ulong_t result;
2659 
2660 	if ((ulwp = find_lwp(tid)) == NULL)
2661 		return (0);
2662 
2663 	if (ulwp->ul_stop && (result = ulwp->ul_sp) != 0) {
2664 		ulwp_unlock(ulwp, udp);
2665 		return (result);
2666 	}
2667 
2668 	result = gettsp_slow(tid);
2669 	ulwp_unlock(ulwp, udp);
2670 	return (result);
2671 }
2672 
2673 /*
2674  * This tells java stack walkers how to find the ucontext
2675  * structure passed to signal handlers.
2676  */
2677 #pragma weak _thr_sighndlrinfo = thr_sighndlrinfo
2678 void
thr_sighndlrinfo(void (** func)(),int * funcsize)2679 thr_sighndlrinfo(void (**func)(), int *funcsize)
2680 {
2681 	*func = &__sighndlr;
2682 	*funcsize = (char *)&__sighndlrend - (char *)&__sighndlr;
2683 }
2684 
2685 /*
2686  * Mark a thread a mutator or reset a mutator to being a default,
2687  * non-mutator thread.
2688  */
2689 #pragma weak _thr_setmutator = thr_setmutator
2690 int
thr_setmutator(thread_t tid,int enabled)2691 thr_setmutator(thread_t tid, int enabled)
2692 {
2693 	ulwp_t *self = curthread;
2694 	uberdata_t *udp = self->ul_uberdata;
2695 	ulwp_t *ulwp;
2696 	int error;
2697 	int cancel_state;
2698 
2699 	enabled = enabled? 1 : 0;
2700 top:
2701 	if (tid == 0) {
2702 		ulwp = self;
2703 		ulwp_lock(ulwp, udp);
2704 	} else if ((ulwp = find_lwp(tid)) == NULL) {
2705 		return (ESRCH);
2706 	}
2707 
2708 	/*
2709 	 * The target thread should be the caller itself or a suspended thread.
2710 	 * This prevents the target from also changing its ul_mutator field.
2711 	 */
2712 	error = 0;
2713 	if (ulwp != self && !ulwp->ul_stop && enabled)
2714 		error = EINVAL;
2715 	else if (ulwp->ul_mutator != enabled) {
2716 		lmutex_lock(&mutatorslock);
2717 		if (mutatorsbarrier) {
2718 			ulwp_unlock(ulwp, udp);
2719 			(void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE,
2720 			    &cancel_state);
2721 			while (mutatorsbarrier)
2722 				(void) cond_wait(&mutatorscv, &mutatorslock);
2723 			(void) pthread_setcancelstate(cancel_state, NULL);
2724 			lmutex_unlock(&mutatorslock);
2725 			goto top;
2726 		}
2727 		ulwp->ul_mutator = enabled;
2728 		lmutex_unlock(&mutatorslock);
2729 	}
2730 
2731 	ulwp_unlock(ulwp, udp);
2732 	return (error);
2733 }
2734 
2735 /*
2736  * Establish a barrier against new mutators.  Any non-mutator trying
2737  * to become a mutator is suspended until the barrier is removed.
2738  */
2739 #pragma weak _thr_mutators_barrier = thr_mutators_barrier
2740 void
thr_mutators_barrier(int enabled)2741 thr_mutators_barrier(int enabled)
2742 {
2743 	int oldvalue;
2744 	int cancel_state;
2745 
2746 	lmutex_lock(&mutatorslock);
2747 
2748 	/*
2749 	 * Wait if trying to set the barrier while it is already set.
2750 	 */
2751 	(void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancel_state);
2752 	while (mutatorsbarrier && enabled)
2753 		(void) cond_wait(&mutatorscv, &mutatorslock);
2754 	(void) pthread_setcancelstate(cancel_state, NULL);
2755 
2756 	oldvalue = mutatorsbarrier;
2757 	mutatorsbarrier = enabled;
2758 	/*
2759 	 * Wakeup any blocked non-mutators when barrier is removed.
2760 	 */
2761 	if (oldvalue && !enabled)
2762 		(void) cond_broadcast(&mutatorscv);
2763 	lmutex_unlock(&mutatorslock);
2764 }
2765 
2766 /*
2767  * Suspend the set of all mutators except for the caller.  The list
2768  * of actively running threads is searched and only the mutators
2769  * in this list are suspended.  Actively running non-mutators remain
2770  * running.  Any other thread is suspended.
2771  */
2772 #pragma weak _thr_suspend_allmutators = thr_suspend_allmutators
2773 int
thr_suspend_allmutators(void)2774 thr_suspend_allmutators(void)
2775 {
2776 	ulwp_t *self = curthread;
2777 	uberdata_t *udp = self->ul_uberdata;
2778 	ulwp_t *ulwp;
2779 	int link_dropped;
2780 
2781 	/*
2782 	 * We single-thread the entire thread suspend/continue mechanism.
2783 	 */
2784 	fork_lock_enter();
2785 
2786 top:
2787 	lmutex_lock(&udp->link_lock);
2788 
2789 	if (suspendingallmutators || suspendedallmutators) {
2790 		lmutex_unlock(&udp->link_lock);
2791 		fork_lock_exit();
2792 		return (EINVAL);
2793 	}
2794 	suspendingallmutators = 1;
2795 
2796 	for (ulwp = self->ul_forw; ulwp != self; ulwp = ulwp->ul_forw) {
2797 		ulwp_lock(ulwp, udp);
2798 		if (!ulwp->ul_mutator) {
2799 			ulwp_unlock(ulwp, udp);
2800 		} else if (ulwp->ul_stop) {	/* already stopped */
2801 			ulwp->ul_stop |= TSTP_MUTATOR;
2802 			ulwp_broadcast(ulwp);
2803 			ulwp_unlock(ulwp, udp);
2804 		} else {
2805 			/*
2806 			 * Move the stopped lwp out of a critical section.
2807 			 */
2808 			if (safe_suspend(ulwp, TSTP_MUTATOR, &link_dropped) ||
2809 			    link_dropped) {
2810 				suspendingallmutators = 0;
2811 				goto top;
2812 			}
2813 		}
2814 	}
2815 
2816 	suspendedallmutators = 1;
2817 	suspendingallmutators = 0;
2818 	lmutex_unlock(&udp->link_lock);
2819 	fork_lock_exit();
2820 	return (0);
2821 }
2822 
2823 /*
2824  * Suspend the target mutator.  The caller is permitted to suspend
2825  * itself.  If a mutator barrier is enabled, the caller will suspend
2826  * itself as though it had been suspended by thr_suspend_allmutators().
2827  * When the barrier is removed, this thread will be resumed.  Any
2828  * suspended mutator, whether suspended by thr_suspend_mutator(), or by
2829  * thr_suspend_allmutators(), can be resumed by thr_continue_mutator().
2830  */
2831 #pragma weak _thr_suspend_mutator = thr_suspend_mutator
2832 int
thr_suspend_mutator(thread_t tid)2833 thr_suspend_mutator(thread_t tid)
2834 {
2835 	if (tid == 0)
2836 		tid = curthread->ul_lwpid;
2837 	return (_thrp_suspend(tid, TSTP_MUTATOR));
2838 }
2839 
2840 /*
2841  * Resume the set of all suspended mutators.
2842  */
2843 #pragma weak _thr_continue_allmutators = thr_continue_allmutators
2844 int
thr_continue_allmutators()2845 thr_continue_allmutators()
2846 {
2847 	ulwp_t *self = curthread;
2848 	uberdata_t *udp = self->ul_uberdata;
2849 	ulwp_t *ulwp;
2850 
2851 	/*
2852 	 * We single-thread the entire thread suspend/continue mechanism.
2853 	 */
2854 	fork_lock_enter();
2855 
2856 	lmutex_lock(&udp->link_lock);
2857 	if (!suspendedallmutators) {
2858 		lmutex_unlock(&udp->link_lock);
2859 		fork_lock_exit();
2860 		return (EINVAL);
2861 	}
2862 	suspendedallmutators = 0;
2863 
2864 	for (ulwp = self->ul_forw; ulwp != self; ulwp = ulwp->ul_forw) {
2865 		mutex_t *mp = ulwp_mutex(ulwp, udp);
2866 		lmutex_lock(mp);
2867 		if (ulwp->ul_stop & TSTP_MUTATOR) {
2868 			ulwp->ul_stop &= ~TSTP_MUTATOR;
2869 			ulwp_broadcast(ulwp);
2870 			if (!ulwp->ul_stop)
2871 				force_continue(ulwp);
2872 		}
2873 		lmutex_unlock(mp);
2874 	}
2875 
2876 	lmutex_unlock(&udp->link_lock);
2877 	fork_lock_exit();
2878 	return (0);
2879 }
2880 
2881 /*
2882  * Resume a suspended mutator.
2883  */
2884 #pragma weak _thr_continue_mutator = thr_continue_mutator
2885 int
thr_continue_mutator(thread_t tid)2886 thr_continue_mutator(thread_t tid)
2887 {
2888 	return (_thrp_continue(tid, TSTP_MUTATOR));
2889 }
2890 
2891 #pragma weak _thr_wait_mutator = thr_wait_mutator
2892 int
thr_wait_mutator(thread_t tid,int dontwait)2893 thr_wait_mutator(thread_t tid, int dontwait)
2894 {
2895 	uberdata_t *udp = curthread->ul_uberdata;
2896 	ulwp_t *ulwp;
2897 	int cancel_state;
2898 	int error = 0;
2899 
2900 	(void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancel_state);
2901 top:
2902 	if ((ulwp = find_lwp(tid)) == NULL) {
2903 		(void) pthread_setcancelstate(cancel_state, NULL);
2904 		return (ESRCH);
2905 	}
2906 
2907 	if (!ulwp->ul_mutator)
2908 		error = EINVAL;
2909 	else if (dontwait) {
2910 		if (!(ulwp->ul_stop & TSTP_MUTATOR))
2911 			error = EWOULDBLOCK;
2912 	} else if (!(ulwp->ul_stop & TSTP_MUTATOR)) {
2913 		cond_t *cvp = ulwp_condvar(ulwp, udp);
2914 		mutex_t *mp = ulwp_mutex(ulwp, udp);
2915 
2916 		(void) cond_wait(cvp, mp);
2917 		(void) lmutex_unlock(mp);
2918 		goto top;
2919 	}
2920 
2921 	ulwp_unlock(ulwp, udp);
2922 	(void) pthread_setcancelstate(cancel_state, NULL);
2923 	return (error);
2924 }
2925 
2926 /* PROBE_SUPPORT begin */
2927 
2928 void
thr_probe_setup(void * data)2929 thr_probe_setup(void *data)
2930 {
2931 	curthread->ul_tpdp = data;
2932 }
2933 
2934 static void *
_thread_probe_getfunc()2935 _thread_probe_getfunc()
2936 {
2937 	return (curthread->ul_tpdp);
2938 }
2939 
2940 void * (*thr_probe_getfunc_addr)(void) = _thread_probe_getfunc;
2941 
2942 /* ARGSUSED */
2943 void
_resume(ulwp_t * ulwp,caddr_t sp,int dontsave)2944 _resume(ulwp_t *ulwp, caddr_t sp, int dontsave)
2945 {
2946 	/* never called */
2947 }
2948 
2949 /* ARGSUSED */
2950 void
_resume_ret(ulwp_t * oldlwp)2951 _resume_ret(ulwp_t *oldlwp)
2952 {
2953 	/* never called */
2954 }
2955 
2956 /* PROBE_SUPPORT end */
2957