1/*
2 * create.c
3 *
4 * Description:
5 * This translation unit implements routines associated with spawning a new
6 * thread.
7 *
8 * --------------------------------------------------------------------------
9 *
10 *      Pthreads-win32 - POSIX Threads Library for Win32
11 *      Copyright(C) 1998 John E. Bossom
12 *      Copyright(C) 1999,2005 Pthreads-win32 contributors
13 *
14 *      Contact Email: rpj@callisto.canberra.edu.au
15 *
16 *      The current list of contributors is contained
17 *      in the file CONTRIBUTORS included with the source
18 *      code distribution. The list can also be seen at the
19 *      following World Wide Web location:
20 *      http://sources.redhat.com/pthreads-win32/contributors.html
21 *
22 *      This library is free software; you can redistribute it and/or
23 *      modify it under the terms of the GNU Lesser General Public
24 *      License as published by the Free Software Foundation; either
25 *      version 2 of the License, or (at your option) any later version.
26 *
27 *      This library is distributed in the hope that it will be useful,
28 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
29 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
30 *      Lesser General Public License for more details.
31 *
32 *      You should have received a copy of the GNU Lesser General Public
33 *      License along with this library in the file COPYING.LIB;
34 *      if not, write to the Free Software Foundation, Inc.,
35 *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
36 */
37
38#include "pthread.h"
39#include "implement.h"
40#if ! defined(_UWIN) && ! defined(WINCE)
41#include <process.h>
42#endif
43
44int
45pthread_create (pthread_t * tid,
46		const pthread_attr_t * attr,
47		void *(PTW32_CDECL *start) (void *), void *arg)
48     /*
49      * ------------------------------------------------------
50      * DOCPUBLIC
51      *      This function creates a thread running the start function,
52      *      passing it the parameter value, 'arg'. The 'attr'
53      *      argument specifies optional creation attributes.
54      *      The identity of the new thread is returned
55      *      via 'tid', which should not be NULL.
56      *
57      * PARAMETERS
58      *      tid
59      *              pointer to an instance of pthread_t
60      *
61      *      attr
62      *              optional pointer to an instance of pthread_attr_t
63      *
64      *      start
65      *              pointer to the starting routine for the new thread
66      *
67      *      arg
68      *              optional parameter passed to 'start'
69      *
70      *
71      * DESCRIPTION
72      *      This function creates a thread running the start function,
73      *      passing it the parameter value, 'arg'. The 'attr'
74      *      argument specifies optional creation attributes.
75      *      The identity of the new thread is returned
76      *      via 'tid', which should not be the NULL pointer.
77      *
78      * RESULTS
79      *              0               successfully created thread,
80      *              EINVAL          attr invalid,
81      *              EAGAIN          insufficient resources.
82      *
83      * ------------------------------------------------------
84      */
85{
86  pthread_t thread;
87  ptw32_thread_t * tp;
88  register pthread_attr_t a;
89  HANDLE threadH = 0;
90  int result = EAGAIN;
91  int run = PTW32_TRUE;
92  ThreadParms *parms = NULL;
93  unsigned int stackSize;
94  int priority;
95  pthread_t self;
96
97  /*
98   * Before doing anything, check that tid can be stored through
99   * without invoking a memory protection error (segfault).
100   * Make sure that the assignment below can't be optimised out by the compiler.
101   * This is assured by conditionally assigning *tid again at the end.
102   */
103  tid->x = 0;
104
105  if (attr != NULL)
106    {
107      a = *attr;
108    }
109  else
110    {
111      a = NULL;
112    }
113
114  if ((thread = ptw32_new ()).p == NULL)
115    {
116      goto FAIL0;
117    }
118
119  tp = (ptw32_thread_t *) thread.p;
120
121  priority = tp->sched_priority;
122
123  if ((parms = (ThreadParms *) malloc (sizeof (*parms))) == NULL)
124    {
125      goto FAIL0;
126    }
127
128  parms->tid = thread;
129  parms->start = start;
130  parms->arg = arg;
131
132#if defined(HAVE_SIGSET_T)
133
134  /*
135   * Threads inherit their initial sigmask from their creator thread.
136   */
137  self = pthread_self();
138  tp->sigmask = ((ptw32_thread_t *)self.p)->sigmask;
139
140#endif /* HAVE_SIGSET_T */
141
142
143  if (a != NULL)
144    {
145      stackSize = (unsigned int)a->stacksize;
146      tp->detachState = a->detachstate;
147      priority = a->param.sched_priority;
148
149#if (THREAD_PRIORITY_LOWEST > THREAD_PRIORITY_NORMAL)
150      /* WinCE */
151#else
152      /* Everything else */
153
154      /*
155       * Thread priority must be set to a valid system level
156       * without altering the value set by pthread_attr_setschedparam().
157       */
158
159      /*
160       * PTHREAD_EXPLICIT_SCHED is the default because Win32 threads
161       * don't inherit their creator's priority. They are started with
162       * THREAD_PRIORITY_NORMAL (win32 value). The result of not supplying
163       * an 'attr' arg to pthread_create() is equivalent to defaulting to
164       * PTHREAD_EXPLICIT_SCHED and priority THREAD_PRIORITY_NORMAL.
165       */
166      if (PTHREAD_INHERIT_SCHED == a->inheritsched)
167	{
168	  /*
169	   * If the thread that called pthread_create() is a Win32 thread
170	   * then the inherited priority could be the result of a temporary
171	   * system adjustment. This is not the case for POSIX threads.
172	   */
173#if ! defined(HAVE_SIGSET_T)
174	  self = pthread_self ();
175#endif
176	  priority = ((ptw32_thread_t *) self.p)->sched_priority;
177	}
178
179#endif
180
181    }
182  else
183    {
184      /*
185       * Default stackSize
186       */
187      stackSize = PTHREAD_STACK_MIN;
188    }
189
190  tp->state = run ? PThreadStateInitial : PThreadStateSuspended;
191
192  tp->keys = NULL;
193
194  /*
195   * Threads must be started in suspended mode and resumed if necessary
196   * after _beginthreadex returns us the handle. Otherwise we set up a
197   * race condition between the creating and the created threads.
198   * Note that we also retain a local copy of the handle for use
199   * by us in case thread.p->threadH gets NULLed later but before we've
200   * finished with it here.
201   */
202
203#if ! (defined (__MINGW64__) || defined(__MINGW32__)) || defined (__MSVCRT__) || defined (__DMC__)
204
205  tp->threadH =
206    threadH =
207    (HANDLE) _beginthreadex ((void *) NULL,	/* No security info             */
208			     stackSize,		/* default stack size   */
209			     ptw32_threadStart,
210			     parms,
211			     (unsigned)
212			     CREATE_SUSPENDED,
213			     (unsigned *) &(tp->thread));
214
215  if (threadH != 0)
216    {
217      if (a != NULL)
218	{
219	  (void) ptw32_setthreadpriority (thread, SCHED_OTHER, priority);
220	}
221
222      if (run)
223	{
224	  ResumeThread (threadH);
225	}
226    }
227
228#else
229
230  {
231    ptw32_mcs_local_node_t stateLock;
232
233    /*
234     * This lock will force pthread_threadStart() to wait until we have
235     * the thread handle and have set the priority.
236     */
237    ptw32_mcs_lock_acquire(&tp->stateLock, &stateLock);
238
239    tp->threadH =
240      threadH =
241      (HANDLE) _beginthread (ptw32_threadStart, stackSize,	/* default stack size   */
242			     parms);
243
244    /*
245     * Make the return code match _beginthreadex's.
246     */
247    if (threadH == (HANDLE) - 1L)
248      {
249        tp->threadH = threadH = 0;
250      }
251    else
252      {
253        if (!run)
254	  {
255	    /*
256	     * beginthread does not allow for create flags, so we do it now.
257	     * Note that beginthread itself creates the thread in SUSPENDED
258	     * mode, and then calls ResumeThread to start it.
259	     */
260	    SuspendThread (threadH);
261	  }
262
263        if (a != NULL)
264	  {
265	    (void) ptw32_setthreadpriority (thread, SCHED_OTHER, priority);
266	  }
267      }
268
269    ptw32_mcs_lock_release (&stateLock);
270  }
271#endif
272
273  result = (threadH != 0) ? 0 : EAGAIN;
274
275  /*
276   * Fall Through Intentionally
277   */
278
279  /*
280   * ------------
281   * Failure Code
282   * ------------
283   */
284
285FAIL0:
286  if (result != 0)
287    {
288
289      ptw32_threadDestroy (thread);
290      tp = NULL;
291
292      if (parms != NULL)
293	{
294	  free (parms);
295	}
296    }
297  else
298    {
299      *tid = thread;
300    }
301
302#if defined(_UWIN)
303  if (result == 0)
304    pthread_count++;
305#endif
306  return (result);
307
308}				/* pthread_create */
309