1 /*
2 * Copyright (c) 2003 Daniel M. Eischen <deischen@gdeb.com>
3 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the author nor the names of any co-contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $FreeBSD: stable/9/lib/libkse/thread/thr_create.c 174689 2007-12-16 23:29:57Z deischen $
31 */
32
33 #include "namespace.h"
34 #include <errno.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <fcntl.h>
38 #include <unistd.h>
39 #include <stddef.h>
40 #include <sys/time.h>
41 #include <machine/reg.h>
42 #include <pthread.h>
43 #include "un-namespace.h"
44 #include "thr_private.h"
45 #include "libc_private.h"
46
47 static void free_thread(struct pthread *curthread, struct pthread *thread);
48 static int create_stack(struct pthread_attr *pattr);
49 static void free_stack(struct pthread_attr *pattr);
50 static void thread_start(struct pthread *curthread,
51 void *(*start_routine) (void *), void *arg);
52
53 __weak_reference(_pthread_create, pthread_create);
54
55 /*
56 * Some notes on new thread creation and first time initializion
57 * to enable multi-threading.
58 *
59 * There are basically two things that need to be done.
60 *
61 * 1) The internal library variables must be initialized.
62 * 2) Upcalls need to be enabled to allow multiple threads
63 * to be run.
64 *
65 * The first may be done as a result of other pthread functions
66 * being called. When _thr_initial is null, _libpthread_init is
67 * called to initialize the internal variables; this also creates
68 * or sets the initial thread. It'd be nice to automatically
69 * have _libpthread_init called on program execution so we don't
70 * have to have checks throughout the library.
71 *
72 * The second part is only triggered by the creation of the first
73 * thread (other than the initial/main thread). If the thread
74 * being created is a scope system thread, then a new KSE/KSEG
75 * pair needs to be allocated. Also, if upcalls haven't been
76 * enabled on the initial thread's KSE, they must be now that
77 * there is more than one thread; this could be delayed until
78 * the initial KSEG has more than one thread.
79 */
80 int
_pthread_create(pthread_t * thread,const pthread_attr_t * attr,void * (* start_routine)(void *),void * arg)81 _pthread_create(pthread_t * thread, const pthread_attr_t * attr,
82 void *(*start_routine) (void *), void *arg)
83 {
84 struct pthread *curthread, *new_thread;
85 struct kse *kse = NULL;
86 struct kse_group *kseg = NULL;
87 kse_critical_t crit;
88 int ret = 0;
89
90 if (_thr_initial == NULL)
91 _libpthread_init(NULL);
92
93 /*
94 * Turn on threaded mode, if failed, it is unnecessary to
95 * do further work.
96 */
97 if (_kse_isthreaded() == 0 && _kse_setthreaded(1)) {
98 return (EAGAIN);
99 }
100 curthread = _get_curthread();
101
102 /*
103 * Allocate memory for the thread structure.
104 * Some functions use malloc, so don't put it
105 * in a critical region.
106 */
107 if ((new_thread = _thr_alloc(curthread)) == NULL) {
108 /* Insufficient memory to create a thread: */
109 ret = EAGAIN;
110 } else {
111 /* Check if default thread attributes are required: */
112 if (attr == NULL || *attr == NULL)
113 /* Use the default thread attributes: */
114 new_thread->attr = _pthread_attr_default;
115 else {
116 new_thread->attr = *(*attr);
117 if ((*attr)->sched_inherit == PTHREAD_INHERIT_SCHED) {
118 /* inherit scheduling contention scop */
119 if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
120 new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
121 else
122 new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
123 /*
124 * scheduling policy and scheduling parameters will be
125 * inherited in following code.
126 */
127 }
128 }
129 if (_thread_scope_system > 0)
130 new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
131 else if ((_thread_scope_system < 0)
132 && (thread != &_thr_sig_daemon))
133 new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
134 if (create_stack(&new_thread->attr) != 0) {
135 /* Insufficient memory to create a stack: */
136 ret = EAGAIN;
137 _thr_free(curthread, new_thread);
138 }
139 else if (((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) &&
140 (((kse = _kse_alloc(curthread, 1)) == NULL)
141 || ((kseg = _kseg_alloc(curthread)) == NULL))) {
142 /* Insufficient memory to create a new KSE/KSEG: */
143 ret = EAGAIN;
144 if (kse != NULL) {
145 kse->k_kcb->kcb_kmbx.km_flags |= KMF_DONE;
146 _kse_free(curthread, kse);
147 }
148 free_stack(&new_thread->attr);
149 _thr_free(curthread, new_thread);
150 }
151 else {
152 if (kseg != NULL) {
153 /* Add the KSE to the KSEG's list of KSEs. */
154 TAILQ_INSERT_HEAD(&kseg->kg_kseq, kse, k_kgqe);
155 kseg->kg_ksecount = 1;
156 kse->k_kseg = kseg;
157 kse->k_schedq = &kseg->kg_schedq;
158 }
159 /*
160 * Write a magic value to the thread structure
161 * to help identify valid ones:
162 */
163 new_thread->magic = THR_MAGIC;
164
165 new_thread->slice_usec = -1;
166 new_thread->start_routine = start_routine;
167 new_thread->arg = arg;
168 new_thread->cancelflags = PTHREAD_CANCEL_ENABLE |
169 PTHREAD_CANCEL_DEFERRED;
170
171 /* No thread is wanting to join to this one: */
172 new_thread->joiner = NULL;
173
174 /*
175 * Initialize the machine context.
176 * Enter a critical region to get consistent context.
177 */
178 crit = _kse_critical_enter();
179 THR_GETCONTEXT(&new_thread->tcb->tcb_tmbx.tm_context);
180 /* Initialize the thread for signals: */
181 new_thread->sigmask = curthread->sigmask;
182 _kse_critical_leave(crit);
183
184 new_thread->tcb->tcb_tmbx.tm_udata = new_thread;
185 new_thread->tcb->tcb_tmbx.tm_context.uc_sigmask =
186 new_thread->sigmask;
187 new_thread->tcb->tcb_tmbx.tm_context.uc_stack.ss_size =
188 new_thread->attr.stacksize_attr;
189 new_thread->tcb->tcb_tmbx.tm_context.uc_stack.ss_sp =
190 new_thread->attr.stackaddr_attr;
191 makecontext(&new_thread->tcb->tcb_tmbx.tm_context,
192 (void (*)(void))thread_start, 3, new_thread,
193 start_routine, arg);
194 /*
195 * Check if this thread is to inherit the scheduling
196 * attributes from its parent:
197 */
198 if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED) {
199 /*
200 * Copy the scheduling attributes.
201 * Lock the scheduling lock to get consistent
202 * scheduling parameters.
203 */
204 THR_SCHED_LOCK(curthread, curthread);
205 new_thread->base_priority =
206 curthread->base_priority &
207 ~THR_SIGNAL_PRIORITY;
208 new_thread->attr.prio =
209 curthread->base_priority &
210 ~THR_SIGNAL_PRIORITY;
211 new_thread->attr.sched_policy =
212 curthread->attr.sched_policy;
213 THR_SCHED_UNLOCK(curthread, curthread);
214 } else {
215 /*
216 * Use just the thread priority, leaving the
217 * other scheduling attributes as their
218 * default values:
219 */
220 new_thread->base_priority =
221 new_thread->attr.prio;
222 }
223 new_thread->active_priority = new_thread->base_priority;
224 new_thread->inherited_priority = 0;
225
226 /* Initialize the mutex queue: */
227 TAILQ_INIT(&new_thread->mutexq);
228
229 /* Initialise hooks in the thread structure: */
230 new_thread->specific = NULL;
231 new_thread->specific_data_count = 0;
232 new_thread->cleanup = NULL;
233 new_thread->flags = 0;
234 new_thread->tlflags = 0;
235 new_thread->sigbackout = NULL;
236 new_thread->continuation = NULL;
237 new_thread->wakeup_time.tv_sec = -1;
238 new_thread->lock_switch = 0;
239 sigemptyset(&new_thread->sigpend);
240 new_thread->check_pending = 0;
241 new_thread->locklevel = 0;
242 new_thread->rdlock_count = 0;
243 new_thread->sigstk.ss_sp = 0;
244 new_thread->sigstk.ss_size = 0;
245 new_thread->sigstk.ss_flags = SS_DISABLE;
246 new_thread->oldsigmask = NULL;
247
248 if (new_thread->attr.suspend == THR_CREATE_SUSPENDED) {
249 new_thread->state = PS_SUSPENDED;
250 new_thread->flags = THR_FLAGS_SUSPENDED;
251 }
252 else
253 new_thread->state = PS_RUNNING;
254
255 /*
256 * System scope threads have their own kse and
257 * kseg. Process scope threads are all hung
258 * off the main process kseg.
259 */
260 if ((new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM) == 0) {
261 new_thread->kseg = _kse_initial->k_kseg;
262 new_thread->kse = _kse_initial;
263 }
264 else {
265 kse->k_curthread = NULL;
266 kse->k_kseg->kg_flags |= KGF_SINGLE_THREAD;
267 new_thread->kse = kse;
268 new_thread->kseg = kse->k_kseg;
269 kse->k_kcb->kcb_kmbx.km_udata = kse;
270 kse->k_kcb->kcb_kmbx.km_curthread = NULL;
271 }
272
273 /*
274 * Schedule the new thread starting a new KSEG/KSE
275 * pair if necessary.
276 */
277 ret = _thr_schedule_add(curthread, new_thread);
278 if (ret != 0)
279 free_thread(curthread, new_thread);
280 else {
281 /* Return a pointer to the thread structure: */
282 (*thread) = new_thread;
283 }
284 }
285 }
286
287 /* Return the status: */
288 return (ret);
289 }
290
291 static void
free_thread(struct pthread * curthread,struct pthread * thread)292 free_thread(struct pthread *curthread, struct pthread *thread)
293 {
294 free_stack(&thread->attr);
295 if ((thread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) {
296 /* Free the KSE and KSEG. */
297 _kseg_free(thread->kseg);
298 _kse_free(curthread, thread->kse);
299 }
300 _thr_free(curthread, thread);
301 }
302
303 static int
create_stack(struct pthread_attr * pattr)304 create_stack(struct pthread_attr *pattr)
305 {
306 int ret;
307
308 /* Check if a stack was specified in the thread attributes: */
309 if ((pattr->stackaddr_attr) != NULL) {
310 pattr->guardsize_attr = 0;
311 pattr->flags |= THR_STACK_USER;
312 ret = 0;
313 }
314 else
315 ret = _thr_stack_alloc(pattr);
316 return (ret);
317 }
318
319 static void
free_stack(struct pthread_attr * pattr)320 free_stack(struct pthread_attr *pattr)
321 {
322 struct kse *curkse;
323 kse_critical_t crit;
324
325 if ((pattr->flags & THR_STACK_USER) == 0) {
326 crit = _kse_critical_enter();
327 curkse = _get_curkse();
328 KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
329 /* Stack routines don't use malloc/free. */
330 _thr_stack_free(pattr);
331 KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
332 _kse_critical_leave(crit);
333 }
334 }
335
336 static void
thread_start(struct pthread * curthread __unused,void * (* start_routine)(void *),void * arg)337 thread_start(struct pthread *curthread __unused, void *(*start_routine) (void *),
338 void *arg)
339 {
340 /* Run the current thread's start routine with argument: */
341 _pthread_exit(start_routine(arg));
342
343 /* This point should never be reached. */
344 PANIC("Thread has resumed after exit");
345 }
346