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[simgrid.git] / src / simix / smx_process.c
1 /* Copyright (c) 2007-2012. The SimGrid Team.
2  * All rights reserved.                                                     */
3
4 /* This program is free software; you can redistribute it and/or modify it
5  * under the terms of the license (GNU LGPL) which comes with this package. */
6
7 #include "smx_private.h"
8 #include "xbt/sysdep.h"
9 #include "xbt/log.h"
10 #include "xbt/dict.h"
11 #include "mc/mc.h"
12
13 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_process, simix,
14                                 "Logging specific to SIMIX (process)");
15
16 unsigned long simix_process_maxpid = 0;
17
18 /**
19  * \brief Returns the current agent.
20  *
21  * This functions returns the currently running SIMIX process.
22  *
23  * \return The SIMIX process
24  */
25 XBT_INLINE smx_process_t SIMIX_process_self(void)
26 {
27   smx_context_t self_context = SIMIX_context_self();
28
29   return self_context ? SIMIX_context_get_data(self_context) : NULL;
30 }
31
32 /**
33  * \brief Returns whether a process has pending asynchronous communications.
34  * \return true if there are asynchronous communications in this process
35  */
36 int SIMIX_process_has_pending_comms(smx_process_t process) {
37
38   return xbt_fifo_size(process->comms) > 0;
39 }
40
41 void SIMIX_pre_process_cleanup(smx_simcall_t simcall, smx_process_t process) {
42   SIMIX_process_cleanup(process);
43 }
44 /**
45  * \brief Moves a process to the list of processes to destroy.
46  */
47 void SIMIX_process_cleanup(smx_process_t process)
48 {
49   XBT_DEBUG("Cleanup process %s (%p), waiting action %p",
50       process->name, process, process->waiting_action);
51
52   /* cancel non-blocking communications */
53   smx_action_t action;
54   while ((action = xbt_fifo_pop(process->comms))) {
55
56     /* make sure no one will finish the comm after this process is destroyed,
57      * because src_proc or dst_proc would be an invalid pointer */
58     SIMIX_comm_cancel(action);
59
60     if (action->comm.src_proc == process) {
61       XBT_DEBUG("Found an unfinished send comm %p (detached = %d), state %d, src = %p, dst = %p",
62           action, action->comm.detached, (int)action->state, action->comm.src_proc, action->comm.dst_proc);
63       action->comm.src_proc = NULL;
64
65       if (action->comm.detached) {
66          if (action->comm.refcount == 0) {
67            XBT_DEBUG("Increase the refcount before destroying it since it's detached");
68            /* I'm not supposed to destroy a detached comm from the sender side,
69             * unless there is no receiver matching the rdv */
70            action->comm.refcount++;
71            SIMIX_comm_destroy(action);
72          }
73          else {
74            XBT_DEBUG("Don't destroy it since its refcount is %d", action->comm.refcount);
75          }
76       } else {
77         SIMIX_comm_destroy(action);
78       }
79     }
80     else if (action->comm.dst_proc == process){
81       XBT_DEBUG("Found an unfinished recv comm %p, state %d, src = %p, dst = %p",
82           action, (int)action->state, action->comm.src_proc, action->comm.dst_proc);
83       action->comm.dst_proc = NULL;
84
85       if (action->comm.detached && action->comm.refcount == 1
86           && action->comm.src_proc != NULL) {
87         /* the comm will be freed right now, remove it from the sender */
88         xbt_fifo_remove(action->comm.src_proc->comms, action);
89       }
90       SIMIX_comm_destroy(action);
91     }
92     else {
93       xbt_die("Communication action %p is in my list but I'm not the sender "
94           "or the receiver", action);
95     }
96   }
97
98   /*xbt_swag_remove(process, simix_global->process_to_run);*/
99   xbt_swag_remove(process, simix_global->process_list);
100   xbt_swag_remove(process, process->smx_host->process_list);
101   xbt_swag_insert(process, simix_global->process_to_destroy);
102   process->context->iwannadie = 0;
103 }
104
105 /** 
106  * Garbage collection
107  *
108  * Should be called some time to time to free the memory allocated for processes
109  * that have finished (or killed).
110  */
111 void SIMIX_process_empty_trash(void)
112 {
113   smx_process_t process = NULL;
114
115   while ((process = xbt_swag_extract(simix_global->process_to_destroy))) {
116     SIMIX_context_free(process->context);
117
118     /* Free the exception allocated at creation time */
119     free(process->running_ctx);
120     xbt_dict_free(&process->properties);
121
122     xbt_fifo_free(process->comms);
123
124     xbt_dynar_free(&process->on_exit);
125
126     free(process->name);
127     free(process);
128   }
129 }
130
131 /**
132  * \brief Creates and runs the maestro process
133  */
134 void SIMIX_create_maestro_process()
135 {
136   smx_process_t maestro = NULL;
137
138   /* Create maestro process and intilialize it */
139   maestro = xbt_new0(s_smx_process_t, 1);
140   maestro->pid = simix_process_maxpid++;
141   maestro->name = (char *) "";
142   maestro->running_ctx = xbt_new(xbt_running_ctx_t, 1);
143   XBT_RUNNING_CTX_INITIALIZE(maestro->running_ctx);
144   maestro->context = SIMIX_context_new(NULL, 0, NULL, NULL, maestro);
145   maestro->simcall.issuer = maestro;
146
147   simix_global->maestro_process = maestro;
148   return;
149 }
150 /**
151  * \brief Stops a process.
152  *
153  * Stops the process, execute all the registered on_exit functions,
154  * register it to the list of the process to restart if needed
155  * and stops its context.
156  */
157 void SIMIX_process_stop(smx_process_t arg) {
158   /* execute the on_exit functions */
159   SIMIX_process_on_exit_runall(arg);
160   /* Add the process to the list of process to restart, only if
161    * the host is down
162    */
163   if (arg->auto_restart && !SIMIX_host_get_state(arg->smx_host)) {
164     SIMIX_host_add_auto_restart_process(arg->smx_host,arg->name,arg->code, arg->data,
165                                         arg->smx_host->name,
166                                         arg->kill_time,
167                                         arg->argc,arg->argv,arg->properties,
168                                         arg->auto_restart);
169   }
170   XBT_DEBUG("Process %s (%s) is dead",arg->name,arg->smx_host->name);
171   /* stop the context */
172   SIMIX_context_stop(arg->context);
173 }
174
175 /**
176  * \brief Same as SIMIX_process_create() but with only one argument (used by timers).
177  * This function frees the argument.
178  * \return the process created
179  */
180 smx_process_t SIMIX_process_create_from_wrapper(smx_process_arg_t args) {
181
182   smx_process_t process;
183   simix_global->create_process_function(
184       &process,
185       args->name,
186       args->code,
187       args->data,
188       args->hostname,
189       args->kill_time,
190       args->argc,
191       args->argv,
192       args->properties,
193       args->auto_restart);
194   xbt_free(args);
195   return process;
196 }
197
198
199 void SIMIX_pre_process_create(smx_simcall_t simcall,
200                           smx_process_t *process,
201                           const char *name,
202                           xbt_main_func_t code,
203                           void *data,
204                           const char *hostname,
205                           double kill_time,
206                           int argc, char **argv,
207                           xbt_dict_t properties,
208                           int auto_restart){
209   return SIMIX_process_create(process, name, code, data, hostname,
210                               kill_time, argc, argv, properties, auto_restart);
211 }
212 /**
213  * \brief Internal function to create a process.
214  *
215  * This function actually creates the process.
216  * It may be called when a SIMCALL_PROCESS_CREATE simcall occurs,
217  * or directly for SIMIX internal purposes. The sure thing is that it's called from maestro context.
218  *
219  * \return the process created
220  */
221 void SIMIX_process_create(smx_process_t *process,
222                           const char *name,
223                           xbt_main_func_t code,
224                           void *data,
225                           const char *hostname,
226                           double kill_time,
227                           int argc, char **argv,
228                           xbt_dict_t properties,
229                           int auto_restart) {
230
231   *process = NULL;
232   smx_host_t host = SIMIX_host_get_by_name(hostname);
233
234   XBT_DEBUG("Start process %s on host '%s'", name, hostname);
235
236   if (!SIMIX_host_get_state(host)) {
237     XBT_WARN("Cannot launch process '%s' on failed host '%s'", name,
238           hostname);
239   }
240   else {
241     *process = xbt_new0(s_smx_process_t, 1);
242
243     xbt_assert(((code != NULL) && (host != NULL)), "Invalid parameters");
244     /* Process data */
245     (*process)->pid = simix_process_maxpid++;
246     (*process)->name = xbt_strdup(name);
247     (*process)->smx_host = host;
248     (*process)->data = data;
249     (*process)->comms = xbt_fifo_new();
250     (*process)->simcall.issuer = *process;
251     /* Process data for auto-restart */
252     (*process)->auto_restart = auto_restart;
253     (*process)->code = code;
254     (*process)->argc = argc;
255     (*process)->argv = argv;
256     (*process)->kill_time = kill_time;
257
258
259     XBT_VERB("Create context %s", (*process)->name);
260     (*process)->context = SIMIX_context_new(code, argc, argv,
261       simix_global->cleanup_process_function, *process);
262
263     (*process)->running_ctx = xbt_new(xbt_running_ctx_t, 1);
264     XBT_RUNNING_CTX_INITIALIZE((*process)->running_ctx);
265
266     /* Add properties */
267     (*process)->properties = properties;
268
269     /* Add the process to it's host process list */
270     xbt_swag_insert(*process, host->process_list);
271
272     XBT_DEBUG("Start context '%s'", (*process)->name);
273
274     /* Now insert it in the global process list and in the process to run list */
275     xbt_swag_insert(*process, simix_global->process_list);
276     XBT_DEBUG("Inserting %s(%s) in the to_run list", (*process)->name, host->name);
277     xbt_dynar_push_as(simix_global->process_to_run, smx_process_t, *process);
278   }
279
280   if (kill_time > SIMIX_get_clock()) {
281     if (simix_global->kill_process_function) {
282       XBT_DEBUG("Process %s(%s) will be kill at time %f", (*process)->name,
283           (*process)->smx_host->name, kill_time);
284       SIMIX_timer_set(kill_time, simix_global->kill_process_function, *process);
285     }
286   }
287 }
288
289 /**
290  * \brief Executes the processes from simix_global->process_to_run.
291  *
292  * The processes of simix_global->process_to_run are run (in parallel if
293  * possible).  On exit, simix_global->process_to_run is empty, and
294  * simix_global->process_that_ran contains the list of processes that just ran.
295  * The two lists are swapped so, be careful when using them before and after a
296  * call to this function.
297  */
298 void SIMIX_process_runall(void)
299 {
300   SIMIX_context_runall();
301
302   xbt_dynar_t tmp = simix_global->process_that_ran;
303   simix_global->process_that_ran = simix_global->process_to_run;
304   simix_global->process_to_run = tmp;
305   xbt_dynar_reset(simix_global->process_to_run);
306 }
307
308 void SIMIX_pre_process_kill(smx_simcall_t simcall, smx_process_t process) {
309   SIMIX_process_kill(process, simcall->issuer);
310 }
311 /**
312  * \brief Internal function to kill a SIMIX process.
313  *
314  * This function may be called when a SIMCALL_PROCESS_KILL simcall occurs,
315  * or directly for SIMIX internal purposes.
316  *
317  * \param process poor victim
318  * \param issuer the process which has sent the PROCESS_KILL. Important to not schedule twice the same process.
319  */
320 void SIMIX_process_kill(smx_process_t process, smx_process_t issuer) {
321
322   XBT_DEBUG("Killing process %s on %s", process->name, process->smx_host->name);
323
324   process->context->iwannadie = 1;
325   process->blocked = 0;
326   process->suspended = 0;
327   /* FIXME: set doexception to 0 also? */
328
329   /* destroy the blocking action if any */
330   if (process->waiting_action) {
331
332     switch (process->waiting_action->type) {
333
334       case SIMIX_ACTION_EXECUTE:          
335       case SIMIX_ACTION_PARALLEL_EXECUTE:
336         SIMIX_host_execution_destroy(process->waiting_action);
337         break;
338
339       case SIMIX_ACTION_COMMUNICATE:
340         xbt_fifo_remove(process->comms, process->waiting_action);
341         SIMIX_comm_cancel(process->waiting_action);
342         break;
343
344         case SIMIX_ACTION_SLEEP:
345           SIMIX_process_sleep_destroy(process->waiting_action);
346           break;
347
348         case SIMIX_ACTION_SYNCHRO:
349           SIMIX_synchro_stop_waiting(process, &process->simcall);
350           SIMIX_synchro_destroy(process->waiting_action);
351           break;
352
353         case SIMIX_ACTION_IO:
354           SIMIX_io_destroy(process->waiting_action);
355           break;
356
357         /* **************************************/
358         /* TUTORIAL: New API                    */
359         case SIMIX_ACTION_NEW_API:
360           SIMIX_new_api_destroy(process->waiting_action);
361           break;
362         /* **************************************/
363
364     }
365   }
366   if(!xbt_dynar_member(simix_global->process_to_run, &(process)) && process != issuer) {
367     xbt_dynar_push_as(simix_global->process_to_run, smx_process_t, process);
368   }
369
370 }
371
372 void SIMIX_pre_process_killall(smx_simcall_t simcall) {
373   SIMIX_process_killall(simcall->issuer);
374 }
375 /**
376  * \brief Kills all running processes.
377  * \param issuer this one will not be killed
378  */
379 void SIMIX_process_killall(smx_process_t issuer)
380 {
381   smx_process_t p = NULL;
382
383   while ((p = xbt_swag_extract(simix_global->process_list))) {
384     if (p != issuer) {
385       SIMIX_process_kill(p,issuer);
386     }
387   }
388
389   SIMIX_context_runall();
390
391   SIMIX_process_empty_trash();
392 }
393
394 void SIMIX_pre_process_change_host(smx_simcall_t simcall, smx_process_t process,
395                                    smx_host_t dest)
396 {
397   process->new_host = dest;
398 }
399 void SIMIX_process_change_host(smx_process_t process,
400              smx_host_t dest)
401 {
402   xbt_assert((process != NULL), "Invalid parameters");
403   xbt_swag_remove(process, process->smx_host->process_list);
404   process->smx_host = dest;
405   xbt_swag_insert(process, dest->process_list);
406 }
407
408
409 void SIMIX_pre_process_suspend(smx_simcall_t simcall, smx_process_t process)
410 {
411   smx_action_t action_suspend =
412       SIMIX_process_suspend(process, simcall->issuer);
413
414   if (process != simcall->issuer) {
415     SIMIX_simcall_answer(simcall);
416   } else {
417     xbt_fifo_push(action_suspend->simcalls, simcall);
418     process->waiting_action = action_suspend;
419     SIMIX_host_execution_suspend(process->waiting_action);
420   }
421   /* If we are suspending ourselves, then just do not finish the simcall now */
422 }
423
424 smx_action_t SIMIX_process_suspend(smx_process_t process, smx_process_t issuer)
425 {
426   xbt_assert((process != NULL), "Invalid parameters");
427
428   if (process->suspended) {
429     XBT_DEBUG("Process '%s' is already suspended", process->name);
430     return NULL;
431   }
432
433   process->suspended = 1;
434
435   /* If we are suspending another process, and it is waiting on an action,
436      suspend its action. */
437   if (process != issuer) {
438
439     if (process->waiting_action) {
440
441       switch (process->waiting_action->type) {
442
443         case SIMIX_ACTION_EXECUTE:
444         case SIMIX_ACTION_PARALLEL_EXECUTE:
445           SIMIX_host_execution_suspend(process->waiting_action);
446           break;
447
448         case SIMIX_ACTION_COMMUNICATE:
449           SIMIX_comm_suspend(process->waiting_action);
450           break;
451
452         case SIMIX_ACTION_SLEEP:
453           SIMIX_process_sleep_suspend(process->waiting_action);
454           break;
455
456         case SIMIX_ACTION_SYNCHRO:
457           /* Suspension is delayed to when the process is rescheduled. */
458           break;
459
460         default:
461           xbt_die("Internal error in SIMIX_process_suspend: unexpected action type %d",
462               (int)process->waiting_action->type);
463       }
464       return NULL;
465     } else {
466       /* Suspension is delayed to when the process is rescheduled. */
467       return NULL;
468     }
469   } else {
470     return SIMIX_host_execute("suspend", process->smx_host, 0.0, 1.0);
471   }
472 }
473
474 void SIMIX_pre_process_resume(smx_simcall_t simcall, smx_process_t process){
475   SIMIX_process_resume(process, simcall->issuer);
476 }
477
478 void SIMIX_process_resume(smx_process_t process, smx_process_t issuer)
479 {
480   xbt_assert((process != NULL), "Invalid parameters");
481
482   XBT_IN("process = %p, issuer = %p", process, issuer);
483
484   if(process->context->iwannadie) {
485     XBT_VERB("Ignoring request to suspend a process that is currently dying.");
486     return;
487   }
488
489   if(!process->suspended) return;
490   process->suspended = 0;
491
492   /* If we are resuming another process, resume the action it was waiting for
493      if any. Otherwise add it to the list of process to run in the next round. */
494   if (process != issuer) {
495
496     if (process->waiting_action) {
497
498       switch (process->waiting_action->type) {
499
500         case SIMIX_ACTION_EXECUTE:          
501         case SIMIX_ACTION_PARALLEL_EXECUTE:
502           SIMIX_host_execution_resume(process->waiting_action);
503           break;
504
505         case SIMIX_ACTION_COMMUNICATE:
506           SIMIX_comm_resume(process->waiting_action);
507           break;
508
509         case SIMIX_ACTION_SLEEP:
510           SIMIX_process_sleep_resume(process->waiting_action);
511           break;
512
513         case SIMIX_ACTION_SYNCHRO:
514           /* I cannot resume it now. This is delayed to when the process is rescheduled at
515            * the end of the synchro. */
516           break;
517
518         default:
519           xbt_die("Internal error in SIMIX_process_resume: unexpected action type %d",
520               (int)process->waiting_action->type);
521       }
522     }
523   } else XBT_WARN("Strange. Process %p is trying to resume himself.", issuer);
524
525   XBT_OUT();
526 }
527
528 int SIMIX_process_get_maxpid(void) {
529   return simix_process_maxpid;
530 }
531
532 int SIMIX_pre_process_count(smx_simcall_t simcall){
533   return SIMIX_process_count();
534 }
535 int SIMIX_process_count(void)
536 {
537   return xbt_swag_size(simix_global->process_list);
538 }
539
540 void* SIMIX_pre_process_self_get_data(smx_simcall_t simcall, smx_process_t self){
541   return SIMIX_process_self_get_data(self);     
542 }
543
544 void* SIMIX_process_self_get_data(smx_process_t self)
545 {
546   xbt_assert(self == SIMIX_process_self(), "This is not the current process");
547
548   if (!self) {
549     return NULL;
550   }
551   return SIMIX_process_get_data(self);
552 }
553
554 void SIMIX_pre_process_set_data(smx_simcall_t simcall, smx_process_t process,
555                                 void *data){
556   SIMIX_process_set_data(process, data);
557 }
558 void SIMIX_process_self_set_data(smx_process_t self, void *data)
559 {
560   xbt_assert(self == SIMIX_process_self(), "This is not the current process");
561
562   SIMIX_process_set_data(self, data);
563 }
564
565 void* SIMIX_pre_process_get_data(smx_simcall_t simcall, smx_process_t process){
566   return SIMIX_process_get_data(process);
567 }
568 void* SIMIX_process_get_data(smx_process_t process)
569 {
570   return process->data;
571 }
572
573 void SIMIX_process_set_data(smx_process_t process, void *data)
574 {
575   process->data = data;
576 }
577
578 smx_host_t SIMIX_pre_process_get_host(smx_simcall_t simcall, smx_process_t process){
579   return SIMIX_process_get_host(process);
580 }
581 smx_host_t SIMIX_process_get_host(smx_process_t process)
582 {
583   return process->smx_host;
584 }
585
586 /* needs to be public and without simcall because it is called
587    by exceptions and logging events */
588 const char* SIMIX_process_self_get_name(void) {
589
590   smx_process_t process = SIMIX_process_self();
591   if (process == NULL || process == simix_global->maestro_process)
592     return "";
593
594   return SIMIX_process_get_name(process);
595 }
596
597 const char* SIMIX_pre_process_get_name(smx_simcall_t simcall, smx_process_t process) {
598   return SIMIX_process_get_name(process);
599 }
600 const char* SIMIX_process_get_name(smx_process_t process)
601 {
602   return process->name;
603 }
604
605 smx_process_t SIMIX_process_get_by_name(const char* name)
606 {
607   smx_process_t proc;
608
609   xbt_swag_foreach(proc, simix_global->process_list)
610   {
611     if(!strcmp(name, proc->name))
612       return proc;
613   }
614   return NULL;
615 }
616
617 int SIMIX_pre_process_is_suspended(smx_simcall_t simcall, smx_process_t process){
618   return SIMIX_process_is_suspended(process);
619 }
620 int SIMIX_process_is_suspended(smx_process_t process)
621 {
622   return process->suspended;
623 }
624
625 xbt_dict_t SIMIX_pre_process_get_properties(smx_simcall_t simcall, smx_process_t process){
626   return SIMIX_process_get_properties(process);
627 }
628 xbt_dict_t SIMIX_process_get_properties(smx_process_t process)
629 {
630   return process->properties;
631 }
632
633 void SIMIX_pre_process_sleep(smx_simcall_t simcall, double duration)
634 {
635   if (MC_is_active()) {
636     MC_process_clock_add(simcall->issuer, duration);
637     simcall_process_sleep__set__result(simcall, SIMIX_DONE);
638     SIMIX_simcall_answer(simcall);
639     return;
640   }
641   smx_action_t action = SIMIX_process_sleep(simcall->issuer, duration);
642   xbt_fifo_push(action->simcalls, simcall);
643   simcall->issuer->waiting_action = action;
644 }
645
646 smx_action_t SIMIX_process_sleep(smx_process_t process, double duration)
647 {
648   smx_action_t action;
649   smx_host_t host = process->smx_host;
650
651   /* check if the host is active */
652   if (surf_workstation_model->extension.
653       workstation.get_state(host->host) != SURF_RESOURCE_ON) {
654     THROWF(host_error, 0, "Host %s failed, you cannot call this function",
655            host->name);
656   }
657
658   action = xbt_mallocator_get(simix_global->action_mallocator);
659   action->type = SIMIX_ACTION_SLEEP;
660   action->name = NULL;
661 #ifdef HAVE_TRACING
662   action->category = NULL;
663 #endif
664
665   action->sleep.host = host;
666   action->sleep.surf_sleep =
667       surf_workstation_model->extension.workstation.sleep(host->host, duration);
668
669   surf_workstation_model->action_data_set(action->sleep.surf_sleep, action);
670   XBT_DEBUG("Create sleep action %p", action);
671
672   return action;
673 }
674
675 void SIMIX_post_process_sleep(smx_action_t action)
676 {
677   smx_simcall_t simcall;
678   e_smx_state_t state;
679
680   while ((simcall = xbt_fifo_shift(action->simcalls))) {
681
682     switch(surf_workstation_model->action_state_get(action->sleep.surf_sleep)){
683       case SURF_ACTION_FAILED:
684         simcall->issuer->context->iwannadie = 1;
685         //SMX_EXCEPTION(simcall->issuer, host_error, 0, "Host failed");
686         break;
687
688       case SURF_ACTION_DONE:
689         state = SIMIX_DONE;
690         break;
691
692       default:
693         THROW_IMPOSSIBLE;
694         break;
695     }
696     if (surf_workstation_model->extension.
697         workstation.get_state(simcall->issuer->smx_host->host) != SURF_RESOURCE_ON) {
698       simcall->issuer->context->iwannadie = 1;
699     }
700     simcall_process_sleep__set__result(simcall, state);
701     simcall->issuer->waiting_action = NULL;
702     SIMIX_simcall_answer(simcall);
703
704   }
705   SIMIX_process_sleep_destroy(action);
706 }
707
708 void SIMIX_process_sleep_destroy(smx_action_t action)
709 {
710   XBT_DEBUG("Destroy action %p", action);
711   if (action->sleep.surf_sleep)
712     action->sleep.surf_sleep->model_type->action_unref(action->sleep.surf_sleep);
713   xbt_mallocator_release(simix_global->action_mallocator, action);
714 }
715
716 void SIMIX_process_sleep_suspend(smx_action_t action)
717 {
718   surf_workstation_model->suspend(action->sleep.surf_sleep);
719 }
720
721 void SIMIX_process_sleep_resume(smx_action_t action)
722 {
723   surf_workstation_model->resume(action->sleep.surf_sleep);
724 }
725
726 /** 
727  * \brief Calling this function makes the process to yield.
728  *
729  * Only the current process can call this function, giving back the control to
730  * maestro.
731  *
732  * \param self the current process
733  */
734 void SIMIX_process_yield(smx_process_t self)
735 {
736   XBT_DEBUG("Yield process '%s'", self->name);
737
738   /* Go into sleep and return control to maestro */
739   SIMIX_context_suspend(self->context);
740
741   /* Ok, maestro returned control to us */
742   XBT_DEBUG("Control returned to me: '%s'", self->name);
743
744   if (self->new_host) {
745     SIMIX_process_change_host(self, self->new_host);
746     self->new_host = NULL;
747   }
748
749   if (self->context->iwannadie){
750     XBT_DEBUG("I wanna die!");
751     SIMIX_process_stop(self);
752   }
753
754   if(self->suspended) {
755     xbt_assert(!self->doexception, "Gloups! This exception may be lost by subsequent calls.");
756     self->suspended = 0;
757     SIMIX_process_suspend(self,self);
758   }
759
760   if (self->doexception) {
761     XBT_DEBUG("Wait, maestro left me an exception");
762     self->doexception = 0;
763     SMX_THROW();
764   }
765
766 }
767
768 /* callback: context fetching */
769 xbt_running_ctx_t *SIMIX_process_get_running_context(void)
770 {
771   return SIMIX_process_self()->running_ctx;
772 }
773
774 /* callback: termination */
775 void SIMIX_process_exception_terminate(xbt_ex_t * e)
776 {
777   xbt_ex_display(e);
778   xbt_abort();
779 }
780
781 smx_context_t SIMIX_process_get_context(smx_process_t p) {
782   return p->context;
783 }
784
785 void SIMIX_process_set_context(smx_process_t p,smx_context_t c) {
786   p->context = c;
787 }
788
789 /**
790  * \brief Returns the list of processes to run.
791  */
792 xbt_dynar_t SIMIX_process_get_runnable(void)
793 {
794   return simix_global->process_to_run;
795 }
796
797 /**
798  * \brief Returns the process from PID.
799  */
800 smx_process_t SIMIX_process_from_PID(int PID)
801 {
802   smx_process_t proc;
803   xbt_swag_foreach(proc, simix_global->process_list)
804   {
805    if(proc->pid == PID)
806    return proc;
807   }
808   return NULL;
809 }
810
811 /** @brief returns a dynar containg all currently existing processes */
812 xbt_dynar_t SIMIX_processes_as_dynar(void) {
813   smx_process_t proc;
814   xbt_dynar_t res = xbt_dynar_new(sizeof(smx_process_t),NULL);
815   xbt_swag_foreach(proc, simix_global->process_list) {
816     xbt_dynar_push(res,&proc);
817   }
818   return res;
819 }
820
821
822 void SIMIX_process_on_exit_runall(smx_process_t process) {
823   s_smx_process_exit_fun_t exit_fun;
824
825   while (!xbt_dynar_is_empty(process->on_exit)) {
826     exit_fun = xbt_dynar_pop_as(process->on_exit,s_smx_process_exit_fun_t);
827     (exit_fun.fun)(exit_fun.arg);
828   }
829 }
830
831 void SIMIX_pre_process_on_exit(smx_simcall_t simcall, smx_process_t process,
832                                int_f_pvoid_t fun, void *data) {
833   SIMIX_process_on_exit(process, fun, data);
834 }
835
836 void SIMIX_process_on_exit(smx_process_t process, int_f_pvoid_t fun, void *data) {
837   xbt_assert(process, "current process not found: are you in maestro context ?");
838
839   if (!process->on_exit) {
840     process->on_exit = xbt_dynar_new(sizeof(s_smx_process_exit_fun_t), NULL);
841   }
842
843   s_smx_process_exit_fun_t exit_fun = {fun, data};
844
845   xbt_dynar_push_as(process->on_exit,s_smx_process_exit_fun_t,exit_fun);
846 }
847
848 void SIMIX_pre_process_auto_restart_set(smx_simcall_t simcall, smx_process_t process,
849                                         int auto_restart) {
850   SIMIX_process_auto_restart_set(process, auto_restart);        
851 }
852 /**
853  * \brief Sets the auto-restart status of the process.
854  * If set to 1, the process will be automatically restarted when its host
855  * comes back.
856  */
857 void SIMIX_process_auto_restart_set(smx_process_t process, int auto_restart) {
858   process->auto_restart = auto_restart;
859 }
860
861 smx_process_t SIMIX_pre_process_restart(smx_simcall_t simcall, smx_process_t process) {
862   return SIMIX_process_restart(process, simcall->issuer);       
863 }
864 /**
865  * \brief Restart a process.
866  * Restart a process, starting it again from the beginning.
867  */
868 smx_process_t SIMIX_process_restart(smx_process_t process, smx_process_t issuer) {
869   XBT_DEBUG("Restarting process %s on %s", process->name, process->smx_host->name);
870   //retrieve the arguments of the old process
871   //FIXME: Factorise this with SIMIX_host_add_auto_restart_process ?
872   s_smx_process_arg_t arg;
873   arg.code = process->code;
874   arg.hostname = process->smx_host->name;
875   arg.kill_time = process->kill_time;
876   arg.argc = process->argc;
877   arg.data = process->data;
878   int i;
879   arg.argv = xbt_new(char*,process->argc + 1);
880   for (i = 0; i < arg.argc; i++) {
881     arg.argv[i] = xbt_strdup(process->argv[i]);
882   }
883   arg.argv[process->argc] = NULL;
884   arg.properties = NULL;
885   arg.auto_restart = process->auto_restart;
886   //kill the old process
887   SIMIX_process_kill(process,issuer);
888   //start the new process
889   smx_process_t new_process;
890   if (simix_global->create_process_function) {
891     simix_global->create_process_function(&new_process,
892                                           arg.argv[0],
893                                           arg.code,
894                                           arg.data,
895                                           arg.hostname,
896                                           arg.kill_time,
897                                           arg.argc,
898                                           arg.argv,
899                                           arg.properties,
900                                           arg.auto_restart);
901   }
902   else {
903     simcall_process_create(&new_process,
904                                           arg.argv[0],
905                                           arg.code,
906                                           arg.data,
907                                           arg.hostname,
908                                           arg.kill_time,
909                                           arg.argc,
910                                           arg.argv,
911                                           arg.properties,
912                                           arg.auto_restart);
913
914   }
915   return new_process;
916 }