source: rtems/cpukit/posix/src/killinfo.c @ ef1a985

Last change on this file since ef1a985 was ef1a985, checked in by Sebastian Huber <sebastian.huber@…>, on Dec 11, 2015 at 9:47:22 AM

Optional POSIX Threads initialization

Update #2408.

  • Property mode set to 100644
File size: 9.8 KB
Line 
1/**
2 * @file
3 *
4 * @brief Send a Signal to a Process
5 * @ingroup POSIXAPI
6 */
7
8/*
9 *  kill() support routine
10 *
11 *  COPYRIGHT (c) 1989-2009.
12 *  On-Line Applications Research Corporation (OAR).
13 *
14 *  The license and distribution terms for this file may be
15 *  found in the file LICENSE in this distribution or at
16 *  http://www.rtems.org/license/LICENSE.
17 */
18
19#if HAVE_CONFIG_H
20#include "config.h"
21#endif
22
23#include <pthread.h>
24#include <signal.h>
25#include <errno.h>
26
27#include <rtems/posix/pthreadimpl.h>
28#include <rtems/posix/psignalimpl.h>
29#include <rtems/score/isr.h>
30#include <rtems/score/statesimpl.h>
31#include <rtems/seterr.h>
32
33/*
34 *  If you enable this, then you get printk() feedback on each path
35 *  and the input to the decision that lead to the decision.  Hopefully
36 *  this will help in debugging the algorithm that distributes process
37 *  signals to individual threads.
38 */
39
40/* #define DEBUG_SIGNAL_PROCESSING */
41#if defined(DEBUG_SIGNAL_PROCESSING)
42  #include <rtems/bspIo.h>
43  #define DEBUG_STEP(_x) printk(_x)
44#else
45  #define DEBUG_STEP(_x)
46#endif
47
48/*
49 *  3.3.2 Send a Signal to a Process, P1003.1b-1993, p. 68
50 *
51 *  NOTE: Behavior of kill() depends on _POSIX_SAVED_IDS.
52 */
53
54#define _POSIX_signals_Is_interested( _api, _mask ) \
55  ( (_api)->signals_unblocked & (_mask) )
56
57int killinfo(
58  pid_t               pid,
59  int                 sig,
60  const union sigval *value
61)
62{
63  sigset_t                     mask;
64  POSIX_API_Control           *api;
65  uint32_t                     the_api;
66  uint32_t                     index;
67  uint32_t                     maximum;
68  Objects_Information         *the_info;
69  Objects_Control            **object_table;
70  Thread_Control              *the_thread;
71  Thread_Control              *interested;
72  Priority_Control             interested_priority;
73  Chain_Node                  *the_node;
74  siginfo_t                    siginfo_struct;
75  siginfo_t                   *siginfo;
76  POSIX_signals_Siginfo_node  *psiginfo;
77  Thread_queue_Heads          *heads;
78
79  /*
80   *  Only supported for the "calling process" (i.e. this node).
81   */
82  if ( pid != getpid() )
83    rtems_set_errno_and_return_minus_one( ESRCH );
84
85  /*
86   *  Validate the signal passed.
87   */
88  if ( !sig )
89    rtems_set_errno_and_return_minus_one( EINVAL );
90
91  if ( !is_valid_signo(sig) )
92    rtems_set_errno_and_return_minus_one( EINVAL );
93
94  /*
95   *  If the signal is being ignored, then we are out of here.
96   */
97  if ( _POSIX_signals_Vectors[ sig ].sa_handler == SIG_IGN )
98    return 0;
99
100  /*
101   *  P1003.1c/Draft 10, p. 33 says that certain signals should always
102   *  be directed to the executing thread such as those caused by hardware
103   *  faults.
104   */
105  if ( (sig == SIGFPE) || (sig == SIGILL) || (sig == SIGSEGV ) )
106      return pthread_kill( pthread_self(), sig );
107
108  mask = signo_to_mask( sig );
109
110  /*
111   *  Build up a siginfo structure
112   */
113  siginfo = &siginfo_struct;
114  siginfo->si_signo = sig;
115  siginfo->si_code = SI_USER;
116  if ( !value ) {
117    siginfo->si_value.sival_int = 0;
118  } else {
119    siginfo->si_value = *value;
120  }
121
122  _Thread_Disable_dispatch();
123
124  /*
125   *  Is the currently executing thread interested?  If so then it will
126   *  get it an execute it as soon as the dispatcher executes.
127   */
128  the_thread = _Thread_Executing;
129
130  api = the_thread->API_Extensions[ THREAD_API_POSIX ];
131  if ( _POSIX_signals_Is_interested( api, mask ) ) {
132    goto process_it;
133  }
134
135  /*
136   *  Is an interested thread waiting for this signal (sigwait())?
137   *
138   *  There is no requirement on the order of threads pending on a sigwait().
139   */
140
141  /* XXX violation of visibility -- need to define thread queue support */
142
143  heads = _POSIX_signals_Wait_queue.Queue.heads;
144  if ( heads != NULL ) {
145    Chain_Control *the_chain = &heads->Heads.Fifo;
146
147    for ( the_node = _Chain_First( the_chain );
148          !_Chain_Is_tail( the_chain, the_node ) ;
149          the_node = the_node->next ) {
150
151      the_thread = THREAD_CHAIN_NODE_TO_THREAD( the_node );
152      api = the_thread->API_Extensions[ THREAD_API_POSIX ];
153
154      #if defined(DEBUG_SIGNAL_PROCESSING)
155        printk( "Waiting Thread=%p option=0x%08x mask=0x%08x blocked=0x%08x\n",
156          the_thread, the_thread->Wait.option, mask, ~api->signals_unblocked);
157      #endif
158
159      /*
160       * Is this thread is actually blocked waiting for the signal?
161       */
162      if (the_thread->Wait.option & mask)
163        goto process_it;
164
165      /*
166       * Is this thread is blocked waiting for another signal but has
167       * not blocked this one?
168       */
169      if (api->signals_unblocked & mask)
170        goto process_it;
171    }
172  }
173
174  /*
175   *  Is any other thread interested?  The highest priority interested
176   *  thread is selected.  In the event of a tie, then the following
177   *  additional criteria is used:
178   *
179   *    + ready thread over blocked
180   *    + blocked on call interruptible by signal (can return EINTR)
181   *    + blocked on call not interruptible by signal
182   *
183   *  This looks at every thread in the system regardless of the creating API.
184   *
185   *  NOTES:
186   *
187   *    + rtems internal threads do not receive signals.
188   */
189  interested = NULL;
190  interested_priority = PRIORITY_MAXIMUM + 1;
191
192  for (the_api = OBJECTS_CLASSIC_API; the_api <= OBJECTS_APIS_LAST; the_api++) {
193
194    /*
195     *  This can occur when no one is interested and an API is not configured.
196     */
197    if ( !_Objects_Information_table[ the_api ] )
198      continue;
199
200    the_info = _Objects_Information_table[ the_api ][ 1 ];
201    if ( !the_info )
202      continue;
203
204    maximum = the_info->maximum;
205    object_table = the_info->local_table;
206
207    for ( index = 1 ; index <= maximum ; index++ ) {
208      the_thread = (Thread_Control *) object_table[ index ];
209
210      if ( !the_thread )
211        continue;
212
213      #if defined(DEBUG_SIGNAL_PROCESSING)
214        printk("\n 0x%08x/0x%08x %d/%d 0x%08x 1",
215          the_thread->Object.id,
216          ((interested) ? interested->Object.id : 0),
217          the_thread->current_priority, interested_priority,
218          the_thread->current_state
219        );
220      #endif
221
222      /*
223       *  If this thread is of lower priority than the interested thread,
224       *  go on to the next thread.
225       */
226      if ( the_thread->current_priority > interested_priority )
227        continue;
228      DEBUG_STEP("2");
229
230      /*
231       *  If this thread is not interested, then go on to the next thread.
232       */
233      api = the_thread->API_Extensions[ THREAD_API_POSIX ];
234
235      #if defined(RTEMS_DEBUG)
236        if ( !api )
237          continue;
238      #endif
239
240      if ( !_POSIX_signals_Is_interested( api, mask ) )
241        continue;
242      DEBUG_STEP("3");
243
244      /*
245       *  Now we know the thread under consideration is interested.
246       *  If the thread under consideration is of higher priority, then
247       *  it becomes the interested thread.
248       *
249       *  NOTE: We initialized interested_priority to PRIORITY_MAXIMUM + 1
250       *        so we never have to worry about deferencing a NULL
251       *        interested thread.
252       */
253      if ( the_thread->current_priority < interested_priority ) {
254        interested   = the_thread;
255        interested_priority = the_thread->current_priority;
256        continue;
257      }
258      DEBUG_STEP("4");
259
260      /*
261       *  Now the thread and the interested thread have the same priority.
262       *  We have to sort through the combinations of blocked/not blocked
263       *  and blocking interruptibutable by signal.
264       *
265       *  If the interested thread is ready, don't think about changing.
266       */
267
268      if ( interested && !_States_Is_ready( interested->current_state ) ) {
269        /* preferred ready over blocked */
270        DEBUG_STEP("5");
271        if ( _States_Is_ready( the_thread->current_state ) ) {
272          interested          = the_thread;
273          interested_priority = the_thread->current_priority;
274          continue;
275        }
276
277        DEBUG_STEP("6");
278        /* prefer blocked/interruptible over blocked/not interruptible */
279        if ( !_States_Is_interruptible_by_signal(interested->current_state) ) {
280          DEBUG_STEP("7");
281          if ( _States_Is_interruptible_by_signal(the_thread->current_state) ) {
282            DEBUG_STEP("8");
283            interested          = the_thread;
284            interested_priority = the_thread->current_priority;
285            continue;
286          }
287        }
288      }
289    }
290  }
291
292  if ( interested ) {
293    the_thread = interested;
294    goto process_it;
295  }
296
297  /*
298   *  OK so no threads were interested right now.  It will be left on the
299   *  global pending until a thread receives it.  The global set of threads
300   *  can change interest in this signal in one of the following ways:
301   *
302   *    + a thread is created with the signal unblocked,
303   *    + pthread_sigmask() unblocks the signal,
304   *    + sigprocmask() unblocks the signal, OR
305   *    + sigaction() which changes the handler to SIG_IGN.
306   */
307  the_thread = NULL;
308  goto post_process_signal;
309
310  /*
311   *  We found a thread which was interested, so now we mark that this
312   *  thread needs to do the post context switch extension so it can
313   *  evaluate the signals pending.
314   */
315process_it:
316
317  /*
318   *  Returns true if the signal was synchronously given to a thread
319   *  blocked waiting for the signal.
320   */
321  if ( _POSIX_signals_Unblock_thread( the_thread, sig, siginfo ) ) {
322    _Thread_Enable_dispatch();
323    return 0;
324  }
325
326post_process_signal:
327
328  /*
329   *  We may have woken up a thread but we definitely need to post the
330   *  signal to the process wide information set.
331   */
332  _POSIX_signals_Set_process_signals( mask );
333
334  if ( _POSIX_signals_Vectors[ sig ].sa_flags == SA_SIGINFO ) {
335
336    psiginfo = (POSIX_signals_Siginfo_node *)
337               _Chain_Get( &_POSIX_signals_Inactive_siginfo );
338    if ( !psiginfo ) {
339      _Thread_Enable_dispatch();
340      rtems_set_errno_and_return_minus_one( EAGAIN );
341    }
342
343    psiginfo->Info = *siginfo;
344
345    _Chain_Append( &_POSIX_signals_Siginfo[ sig ], &psiginfo->Node );
346  }
347
348  DEBUG_STEP("\n");
349  _Thread_Enable_dispatch();
350  return 0;
351}
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