95ca398d15a717509bdc38aab7e303f4cc6288fb
[OpenSRF.git] / src / libopensrf / osrf_prefork.c
1 #include <opensrf/osrf_prefork.h>
2 #include <opensrf/osrf_app_session.h>
3 #include <opensrf/osrf_application.h>
4 #include <signal.h>
5
6 //#define READ_BUFSIZE 4096
7 #define READ_BUFSIZE 1024
8 //#define MAX_BUFSIZE 10485760 /* 10M enough? ;) */
9 #define ABS_MAX_CHILDREN 256
10
11 struct prefork_simple_struct {
12         int max_requests;
13         int min_children;
14         int max_children;
15         int fd;
16         int data_to_child;
17         int data_to_parent;
18         int current_num_children;
19         int keepalive; /* keepalive time for stateful sessions */
20         char* appname;
21         struct prefork_child_struct* first_child;
22         transport_client* connection;
23 };
24 typedef struct prefork_simple_struct prefork_simple;
25
26 struct prefork_child_struct {
27         pid_t pid;
28         int read_data_fd;
29         int write_data_fd;
30         int read_status_fd;
31         int write_status_fd;
32         int min_children;
33         int available;
34         int max_requests;
35         char* appname;
36         int keepalive;
37         struct prefork_child_struct* next;
38 };
39
40 typedef struct prefork_child_struct prefork_child;
41
42 static prefork_simple* prefork_simple_init( transport_client* client,
43         int max_requests, int min_children, int max_children );
44 static prefork_child* launch_child( prefork_simple* forker );
45 static void prefork_launch_children( prefork_simple* forker );
46 static void prefork_run(prefork_simple* forker);
47 static void add_prefork_child( prefork_simple* forker, prefork_child* child );
48
49 //static prefork_child* find_prefork_child( prefork_simple* forker, pid_t pid );
50
51 static void del_prefork_child( prefork_simple* forker, pid_t pid );
52 static void check_children( prefork_simple* forker, int forever );
53 static void prefork_child_process_request(prefork_child*, char* data);
54 static int prefork_child_init_hook(prefork_child*);
55 static prefork_child* prefork_child_init(
56                 int max_requests, int read_data_fd, int write_data_fd,
57                 int read_status_fd, int write_status_fd );
58
59 /* listens on the 'data_to_child' fd and wait for incoming data */
60 static void prefork_child_wait( prefork_child* child );
61 static int prefork_free( prefork_simple* );
62 static int prefork_child_free( prefork_child* );
63 static void osrf_prefork_register_routers( const char* appname );
64 static void osrf_prefork_child_exit( prefork_child* );
65
66
67 /* true if we just deleted a child.  This will allow us to make sure we're
68         not trying to use freed memory */
69 static sig_atomic_t child_dead;
70
71 static void sigchld_handler( int sig );
72
73 int osrf_prefork_run(const char* appname) {
74
75         if(!appname) {
76                 osrfLogError( OSRF_LOG_MARK, "osrf_prefork_run requires an appname to run!");
77                 return -1;
78         }
79
80         set_proc_title( "OpenSRF Listener [%s]", appname );
81
82         int maxr = 1000; 
83         int maxc = 10;
84         int minc = 3;
85     int kalive = 5;
86
87         osrfLogInfo( OSRF_LOG_MARK, "Loading config in osrf_forker for app %s", appname);
88
89         char* max_req = osrf_settings_host_value("/apps/%s/unix_config/max_requests", appname);
90         char* min_children = osrf_settings_host_value("/apps/%s/unix_config/min_children", appname);
91         char* max_children = osrf_settings_host_value("/apps/%s/unix_config/max_children", appname);
92         char* keepalive = osrf_settings_host_value("/apps/%s/keepalive", appname);
93
94         if(!keepalive) osrfLogWarning( OSRF_LOG_MARK, "Keepalive is not defined, assuming %d", kalive);
95         else kalive = atoi(keepalive);
96
97         if(!max_req) osrfLogWarning( OSRF_LOG_MARK, "Max requests not defined, assuming %d", maxr);
98         else maxr = atoi(max_req);
99
100         if(!min_children) osrfLogWarning( OSRF_LOG_MARK, "Min children not defined, assuming %d", minc);
101         else minc = atoi(min_children);
102
103         if(!max_children) osrfLogWarning( OSRF_LOG_MARK, "Max children not defined, assuming %d", maxc);
104         else maxc = atoi(max_children);
105
106     free(keepalive);
107         free(max_req);
108         free(min_children);
109         free(max_children);
110         /* --------------------------------------------------- */
111
112         char* resc = va_list_to_string("%s_listener", appname);
113
114         if(!osrfSystemBootstrapClientResc( NULL, NULL, resc )) {
115                 osrfLogError( OSRF_LOG_MARK, "Unable to bootstrap client for osrf_prefork_run()");
116                 free(resc);
117                 return -1;
118         }
119
120         free(resc);
121
122         prefork_simple* forker = prefork_simple_init(
123                 osrfSystemGetTransportClient(), maxr, minc, maxc);
124
125         if(forker == NULL) {
126                 osrfLogError( OSRF_LOG_MARK, "osrf_prefork_run() failed to create prefork_simple object");
127                 return -1;
128         }
129
130         forker->appname = strdup(appname);
131         forker->keepalive       = kalive;
132
133         prefork_launch_children(forker);
134
135         osrf_prefork_register_routers(appname);
136         
137         osrfLogInfo( OSRF_LOG_MARK, "Launching osrf_forker for app %s", appname);
138         prefork_run(forker);
139         
140         osrfLogWarning( OSRF_LOG_MARK, "prefork_run() retuned - how??");
141         prefork_free(forker);
142         return 0;
143
144 }
145
146 /* sends the "register" packet to the specified router */
147 static void osrf_prefork_send_router_registration(const char* appname, const char* routerName, const char* routerDomain) {
148         transport_client* client = osrfSystemGetTransportClient();
149     char* jid = va_list_to_string( "%s@%s/router", routerName, routerDomain );
150     osrfLogInfo( OSRF_LOG_MARK, "%s registering with router %s", appname, jid );
151     transport_message* msg = message_init("registering", NULL, NULL, jid, NULL );
152     message_set_router_info( msg, NULL, NULL, appname, "register", 0 );
153     client_send_message( client, msg );
154     message_free( msg );
155     free(jid);
156 }
157
158 /** parses a single "complex" router configuration chunk */
159 static void osrf_prefork_parse_router_chunk(const char* appname, jsonObject* routerChunk) {
160
161     char* routerName = jsonObjectGetString(jsonObjectGetKey(routerChunk, "name"));
162     char* domain = jsonObjectGetString(jsonObjectGetKey(routerChunk, "domain"));
163     jsonObject* services = jsonObjectGetKey(routerChunk, "services");
164     osrfLogDebug(OSRF_LOG_MARK, "found router config with domain %s and name %s", routerName, domain);
165
166     if(services && services->type == JSON_HASH) {
167         osrfLogDebug(OSRF_LOG_MARK, "investigating router information...");
168         services = jsonObjectGetKey(services, "service");
169         int j;
170         for(j = 0; j < services->size; j++ ) {
171             char* service = jsonObjectGetString(jsonObjectGetIndex(services, j));
172             if(!strcmp(appname, service))
173                 osrf_prefork_send_router_registration(appname, routerName, domain);
174         }
175     } else {
176         osrf_prefork_send_router_registration(appname, routerName, domain);
177     }
178 }
179
180 static void osrf_prefork_register_routers( const char* appname ) {
181
182     jsonObject* routerInfo = osrfConfigGetValueObject(NULL, "/routers/router");
183
184     int i;
185     for(i = 0; i < routerInfo->size; i++) {
186         jsonObject* routerChunk = jsonObjectGetIndex(routerInfo, i);
187
188         if(routerChunk->type == JSON_STRING) {
189             /* this accomodates simple router configs */
190             char* routerName = osrfConfigGetValue( NULL, "/router_name" );
191             char* domain = osrfConfigGetValue(NULL, "/routers/router");
192             osrfLogDebug(OSRF_LOG_MARK, "found simple router settings with router name %s", routerName);
193             osrf_prefork_send_router_registration(appname, routerName, domain);
194
195         } else {
196             osrf_prefork_parse_router_chunk(appname, routerChunk);
197         }
198     }
199 }
200
201 static int prefork_child_init_hook(prefork_child* child) {
202
203         if(!child) return -1;
204         osrfLogDebug( OSRF_LOG_MARK, "Child init hook for child %d", child->pid);
205
206     osrfSystemInitCache();
207         char* resc = va_list_to_string("%s_drone",child->appname);
208
209    /* if we're a source-client, tell the logger now that we're a new process*/
210    char* isclient = osrfConfigGetValue(NULL, "/client");
211    if( isclient && !strcasecmp(isclient,"true") )
212       osrfLogSetIsClient(1);
213    free(isclient);
214
215
216         /* we want to remove traces of our parents socket connection 
217          * so we can have our own */
218         osrfSystemIgnoreTransportClient();
219
220         if(!osrfSystemBootstrapClientResc( NULL, NULL, resc)) {
221                 osrfLogError( OSRF_LOG_MARK, "Unable to bootstrap client for osrf_prefork_run()");
222                 free(resc);
223                 return -1;
224         }
225
226         free(resc);
227
228         if( ! osrfAppRunChildInit(child->appname) ) {
229                 osrfLogDebug(OSRF_LOG_MARK, "Prefork child_init succeeded\n");
230         } else {
231                 osrfLogError(OSRF_LOG_MARK, "Prefork child_init failed\n");
232                 return -1;
233         }
234
235         set_proc_title( "OpenSRF Drone [%s]", child->appname );
236         return 0;
237 }
238
239 static void prefork_child_process_request(prefork_child* child, char* data) {
240         if( !child ) return;
241
242         transport_client* client = osrfSystemGetTransportClient();
243
244         if(!client_connected(client)) {
245                 osrfSystemIgnoreTransportClient();
246                 osrfLogWarning(OSRF_LOG_MARK, "Reconnecting child to opensrf after disconnect...");
247                 if(!osrf_system_bootstrap_client(NULL, NULL)) {
248                         osrfLogError( OSRF_LOG_MARK, 
249                                 "Unable to bootstrap client in prefork_child_process_request()");
250                         sleep(1);
251          osrf_prefork_child_exit(child);
252                 }
253         }
254
255         /* construct the message from the xml */
256         transport_message* msg = new_message_from_xml( data );
257
258         osrfAppSession* session = osrf_stack_transport_handler(msg, child->appname);
259         if(!session) return;
260
261         if( session->stateless && session->state != OSRF_SESSION_CONNECTED ) {
262                 osrfAppSessionFree( session );
263                 return;
264         }
265
266         osrfLogDebug( OSRF_LOG_MARK, "Entering keepalive loop for session %s", session->session_id );
267         int keepalive = child->keepalive;
268         int retval;
269         int recvd;
270         time_t start;
271         time_t end;
272
273         while(1) {
274
275                 osrfLogDebug(OSRF_LOG_MARK, 
276                                 "osrf_prefork calling queue_wait [%d] in keepalive loop", keepalive);
277                 start           = time(NULL);
278                 retval  = osrf_app_session_queue_wait(session, keepalive, &recvd);
279                 end             = time(NULL);
280
281                 osrfLogDebug(OSRF_LOG_MARK, "Data received == %d", recvd);
282
283                 if(retval) {
284                         osrfLogError(OSRF_LOG_MARK, "queue-wait returned non-success %d", retval);
285                         break;
286                 }
287
288                 /* see if the client disconnected from us */
289                 if(session->state != OSRF_SESSION_CONNECTED) break;
290
291                 /* if no data was reveived within the timeout interval */
292                 if( !recvd && (end - start) >= keepalive ) {
293                         osrfLogInfo(OSRF_LOG_MARK, "No request was received in %d seconds, exiting stateful session", keepalive);
294                         osrfAppSessionStatus( 
295                                         session, 
296                                         OSRF_STATUS_TIMEOUT, 
297                                         "osrfConnectStatus", 
298                                         0, "Disconnected on timeout" );
299
300                         break;
301                 }
302         }
303
304         osrfLogDebug( OSRF_LOG_MARK, "Exiting keepalive loop for session %s", session->session_id );
305         osrfAppSessionFree( session );
306         return;
307 }
308
309
310 static prefork_simple*  prefork_simple_init( transport_client* client, 
311                 int max_requests, int min_children, int max_children ) {
312
313         if( min_children > max_children ) {
314                 osrfLogError( OSRF_LOG_MARK,  "min_children (%d) is greater "
315                                 "than max_children (%d)", min_children, max_children );
316                 return NULL;
317         }
318
319         if( max_children > ABS_MAX_CHILDREN ) {
320                 osrfLogError( OSRF_LOG_MARK,  "max_children (%d) is greater than ABS_MAX_CHILDREN (%d)",
321                                 max_children, ABS_MAX_CHILDREN );
322                 return NULL;
323         }
324
325         osrfLogInfo(OSRF_LOG_MARK, "Prefork launching child with max_request=%d,"
326                 "min_children=%d, max_children=%d", max_requests, min_children, max_children );
327
328         /* flesh out the struct */
329         prefork_simple* prefork = (prefork_simple*) safe_malloc(sizeof(prefork_simple));        
330         prefork->max_requests = max_requests;
331         prefork->min_children = min_children;
332         prefork->max_children = max_children;
333         prefork->fd           = 0;
334         prefork->data_to_child = 0;
335         prefork->data_to_parent = 0;
336         prefork->current_num_children = 0;
337         prefork->keepalive    = 0;
338         prefork->appname      = NULL;
339         prefork->first_child = NULL;
340         prefork->connection = client;
341
342         return prefork;
343 }
344
345 static prefork_child* launch_child( prefork_simple* forker ) {
346
347         pid_t pid;
348         int data_fd[2];
349         int status_fd[2];
350
351         /* Set up the data pipes and add the child struct to the parent */
352         if( pipe(data_fd) < 0 ) { /* build the data pipe*/
353                 osrfLogError( OSRF_LOG_MARK,  "Pipe making error" );
354                 return NULL;
355         }
356
357         if( pipe(status_fd) < 0 ) {/* build the status pipe */
358                 osrfLogError( OSRF_LOG_MARK,  "Pipe making error" );
359                 return NULL;
360         }
361
362         osrfLogInternal( OSRF_LOG_MARK,  "Pipes: %d %d %d %d", data_fd[0], data_fd[1], status_fd[0], status_fd[1] );
363         prefork_child* child = prefork_child_init( forker->max_requests, data_fd[0], 
364                         data_fd[1], status_fd[0], status_fd[1] );
365
366         child->appname = strdup(forker->appname);
367         child->keepalive = forker->keepalive;
368
369
370         add_prefork_child( forker, child );
371
372         if( (pid=fork()) < 0 ) {
373                 osrfLogError( OSRF_LOG_MARK,  "Forking Error" );
374                 return NULL;
375         }
376
377         if( pid > 0 ) {  /* parent */
378
379                 signal(SIGCHLD, sigchld_handler);
380                 (forker->current_num_children)++;
381                 child->pid = pid;
382
383                 osrfLogDebug( OSRF_LOG_MARK,  "Parent launched %d", pid );
384                 /* *no* child pipe FD's can be closed or the parent will re-use fd's that
385                         the children are currently using */
386                 return child;
387         }
388
389         else { /* child */
390
391                 osrfLogInternal( OSRF_LOG_MARK, "I am  new child with read_data_fd = %d and write_status_fd = %d",
392                         child->read_data_fd, child->write_status_fd );
393
394                 child->pid = getpid();
395                 close( child->write_data_fd );
396                 close( child->read_status_fd );
397
398                 /* do the initing */
399                 if( prefork_child_init_hook(child) == -1 ) {
400                         osrfLogError(OSRF_LOG_MARK, 
401                                 "Forker child going away because we could not connect to OpenSRF...");
402          osrf_prefork_child_exit(child);
403                 }
404
405                 prefork_child_wait( child );
406       osrf_prefork_child_exit(child); /* just to be sure */
407          }
408         return NULL;
409 }
410
411 static void osrf_prefork_child_exit(prefork_child* child) {
412    osrfAppRunExitCode();
413    exit(0);
414 }
415
416 static void prefork_launch_children( prefork_simple* forker ) {
417         if(!forker) return;
418         int c = 0;
419         while( c++ < forker->min_children )
420                 launch_child( forker );
421 }
422
423
424 static void sigchld_handler( int sig ) {
425         signal(SIGCHLD, sigchld_handler);
426         child_dead = 1;
427 }
428
429
430 void reap_children( prefork_simple* forker ) {
431
432         pid_t child_pid;
433         int status;
434
435         while( (child_pid=waitpid(-1,&status,WNOHANG)) > 0) 
436                 del_prefork_child( forker, child_pid ); 
437
438         /* replenish */
439         while( forker->current_num_children < forker->min_children ) 
440                 launch_child( forker );
441
442         child_dead = 0;
443 }
444
445 static void prefork_run(prefork_simple* forker) {
446
447         if( forker->first_child == NULL )
448                 return;
449
450         transport_message* cur_msg = NULL;
451
452
453         while(1) {
454
455                 if( forker->first_child == NULL ) {/* no more children */
456                         osrfLogWarning( OSRF_LOG_MARK, "No more children..." );
457                         return;
458                 }
459
460                 osrfLogDebug( OSRF_LOG_MARK, "Forker going into wait for data...");
461                 cur_msg = client_recv( forker->connection, -1 );
462
463                 //fprintf(stderr, "Got Data %f\n", get_timestamp_millis() );
464
465                 if( cur_msg == NULL ) continue;
466
467                 int honored = 0;        /* true if we've serviced the request */
468                 int no_recheck = 0;
469
470                 while( ! honored ) {
471
472                         if(!no_recheck) check_children( forker, 0 ); 
473                         no_recheck = 0;
474
475                         osrfLogDebug( OSRF_LOG_MARK,  "Server received inbound data" );
476                         int k;
477                         prefork_child* cur_child = forker->first_child;
478
479                         /* Look for an available child */
480                         for( k = 0; k < forker->current_num_children; k++ ) {
481
482                                 osrfLogInternal( OSRF_LOG_MARK, "Searching for available child. cur_child->pid = %d", cur_child->pid );
483                                 osrfLogInternal( OSRF_LOG_MARK, "Current num children %d and loop %d", forker->current_num_children, k);
484                         
485                                 if( cur_child->available ) {
486                                         osrfLogDebug( OSRF_LOG_MARK,  "forker sending data to %d", cur_child->pid );
487
488                                         message_prepare_xml( cur_msg );
489                                         char* data = cur_msg->msg_xml;
490                                         if( ! data || strlen(data) < 1 ) break;
491
492                                         cur_child->available = 0;
493                                         osrfLogInternal( OSRF_LOG_MARK,  "Writing to child fd %d", cur_child->write_data_fd );
494
495                                         int written = 0;
496                                         //fprintf(stderr, "Writing Data %f\n", get_timestamp_millis() );
497                                         if( (written = write( cur_child->write_data_fd, data, strlen(data) + 1 )) < 0 ) {
498                                                 osrfLogWarning( OSRF_LOG_MARK, "Write returned error %d", errno);
499                                                 cur_child = cur_child->next;
500                                                 continue;
501                                         }
502
503                                         //fprintf(stderr, "Wrote %d bytes to child\n", written);
504
505                                         forker->first_child = cur_child->next;
506                                         honored = 1;
507                                         break;
508                                 } else 
509                                         cur_child = cur_child->next;
510                         } 
511
512                         /* if none available, add a new child if we can */
513                         if( ! honored ) {
514                                 osrfLogDebug( OSRF_LOG_MARK, "Not enough children, attempting to add...");
515
516                                 if( forker->current_num_children < forker->max_children ) {
517                                         osrfLogDebug( OSRF_LOG_MARK,  "Launching new child with current_num = %d",
518                                                         forker->current_num_children );
519
520                                         prefork_child* new_child = launch_child( forker );
521                     if( new_child ) {
522
523                                             message_prepare_xml( cur_msg );
524                                             char* data = cur_msg->msg_xml;
525
526                         if( data ) {
527                             int len = strlen(data);
528
529                             if( len > 0 ) {
530                                                     new_child->available = 0;
531                                                     osrfLogDebug( OSRF_LOG_MARK,  "Writing to new child fd %d : pid %d", 
532                                                                 new_child->write_data_fd, new_child->pid );
533         
534                                                     if( write( new_child->write_data_fd, data, len + 1 ) >= 0 ) {
535                                                         forker->first_child = new_child->next;
536                                                         honored = 1;
537                                 }
538                             }
539                         }
540                     }
541
542                                 }
543                         }
544
545                         if( !honored ) {
546                                 osrfLogWarning( OSRF_LOG_MARK,  "No children available, waiting...");
547
548                                 check_children( forker, 1 );  /* non-poll version */
549                                 /* tell the loop no to call check_children again, since we're calling it now */
550                                 no_recheck = 1;
551                         }
552
553                         if( child_dead )
554                                 reap_children(forker);
555
556
557                         //fprintf(stderr, "Parent done with request %f\n", get_timestamp_millis() );
558
559                 } // honored?
560
561                 message_free( cur_msg );
562
563         } /* top level listen loop */
564
565 }
566
567
568 /** XXX Add a flag which tells select() to wait forever on children
569  * in the best case, this will be faster than calling usleep(x), and
570  * in the worst case it won't be slower and will do less logging...
571  */
572
573 static void check_children( prefork_simple* forker, int forever ) {
574
575         //check_begin:
576
577         int select_ret;
578         fd_set read_set;
579         FD_ZERO(&read_set);
580         int max_fd = 0;
581         int n;
582
583
584         if( child_dead )
585                 reap_children(forker);
586
587         prefork_child* cur_child = forker->first_child;
588
589         int i;
590         for( i = 0; i!= forker->current_num_children; i++ ) {
591
592                 if( cur_child->read_status_fd > max_fd )
593                         max_fd = cur_child->read_status_fd;
594                 FD_SET( cur_child->read_status_fd, &read_set );
595                 cur_child = cur_child->next;
596         }
597
598         FD_CLR(0,&read_set);/* just to be sure */
599
600         if( forever ) {
601                 osrfLogWarning(OSRF_LOG_MARK, "We have no children available - waiting for one to show up...");
602
603                 if( (select_ret=select( max_fd + 1 , &read_set, NULL, NULL, NULL)) == -1 ) {
604                         osrfLogWarning( OSRF_LOG_MARK,  "Select returned error %d on check_children", errno );
605                 }
606                 osrfLogInfo(OSRF_LOG_MARK, "select() completed after waiting on children to become available");
607
608         } else {
609
610                 struct timeval tv;
611                 tv.tv_sec       = 0;
612                 tv.tv_usec      = 0;
613         
614                 if( (select_ret=select( max_fd + 1 , &read_set, NULL, NULL, &tv)) == -1 ) {
615                         osrfLogWarning( OSRF_LOG_MARK,  "Select returned error %d on check_children", errno );
616                 }
617         }
618
619         if( select_ret == 0 )
620                 return;
621
622         /* see if one of a child has told us it's done */
623         cur_child = forker->first_child;
624         int j;
625         int num_handled = 0;
626         for( j = 0; j!= forker->current_num_children && num_handled < select_ret ; j++ ) {
627
628                 if( FD_ISSET( cur_child->read_status_fd, &read_set ) ) {
629                         //printf( "Server received status from a child %d\n", cur_child->pid );
630                         osrfLogDebug( OSRF_LOG_MARK,  "Server received status from a child %d", cur_child->pid );
631
632                         num_handled++;
633
634                         /* now suck off the data */
635                         char buf[64];
636                         osrf_clearbuf( buf, sizeof(buf) );
637                         if( (n=read(cur_child->read_status_fd, buf, sizeof(buf) - 1)) < 0 ) {
638                                 osrfLogWarning( OSRF_LOG_MARK, "Read error after select in child status read with errno %d", errno);
639                         }
640                         else {
641                                 buf[n] = '\0';
642                                 osrfLogDebug( OSRF_LOG_MARK,  "Read %d bytes from status buffer: %s", n, buf );
643                         }
644                         cur_child->available = 1;
645                 }
646                 cur_child = cur_child->next;
647         } 
648
649 }
650
651
652 static void prefork_child_wait( prefork_child* child ) {
653
654         int i,n;
655         growing_buffer* gbuf = buffer_init( READ_BUFSIZE );
656         char buf[READ_BUFSIZE];
657         osrf_clearbuf( buf, sizeof(buf) );
658
659         for( i = 0; i < child->max_requests; i++ ) {
660
661                 n = -1;
662                 int gotdata = 0;
663                 clr_fl(child->read_data_fd, O_NONBLOCK );
664
665                 while( (n=read(child->read_data_fd, buf, READ_BUFSIZE-1)) > 0 ) {
666                         buf[n] = '\0';
667                         osrfLogDebug(OSRF_LOG_MARK, "Prefork child read %d bytes of data", n);
668                         if(!gotdata)
669                                 set_fl(child->read_data_fd, O_NONBLOCK );
670                         buffer_add( gbuf, buf );
671                         osrf_clearbuf( buf, sizeof(buf) );
672                         gotdata = 1;
673                 }
674
675                 if( errno == EAGAIN ) n = 0;
676
677       if( errno == EPIPE ) {
678          osrfLogDebug(OSRF_LOG_MARK, "C child attempted read on broken pipe, exiting...");
679          break;
680       }
681
682                 if( n < 0 ) {
683                         osrfLogWarning( OSRF_LOG_MARK,  "Prefork child read returned error with errno %d", errno );
684                         break;
685
686                 } else if( gotdata ) {
687                         osrfLogDebug(OSRF_LOG_MARK, "Prefork child got a request.. processing..");
688                         prefork_child_process_request(child, gbuf->buf);
689                         buffer_reset( gbuf );
690                 }
691
692                 if( i < child->max_requests - 1 ) 
693                         write( child->write_status_fd, "available" /*less than 64 bytes*/, 9 );
694         }
695
696         buffer_free(gbuf);
697
698         osrfLogDebug( OSRF_LOG_MARK, "Child with max-requests=%d, num-served=%d exiting...[%ld]", 
699                         child->max_requests, i, (long) getpid() );
700
701    osrf_prefork_child_exit(child); /* just to be sure */
702 }
703
704
705 static void add_prefork_child( prefork_simple* forker, prefork_child* child ) {
706         
707         if( forker->first_child == NULL ) {
708                 forker->first_child = child;
709                 child->next = child;
710                 return;
711         }
712
713         /* we put the child in as the last because, regardless, 
714                 we have to do the DLL splice dance, and this is the
715            simplest way */
716
717         prefork_child* start_child = forker->first_child;
718         while(1) {
719                 if( forker->first_child->next == start_child ) 
720                         break;
721                 forker->first_child = forker->first_child->next;
722         }
723
724         /* here we know that forker->first_child is the last element 
725                 in the list and start_child is the first.  Insert the
726                 new child between them*/
727
728         forker->first_child->next = child;
729         child->next = start_child;
730         return;
731 }
732
733 //static prefork_child* find_prefork_child( prefork_simple* forker, pid_t pid ) {
734 //
735 //      if( forker->first_child == NULL ) { return NULL; }
736 //      prefork_child* start_child = forker->first_child;
737 //      do {
738 //              if( forker->first_child->pid == pid ) 
739 //                      return forker->first_child;
740 //      } while( (forker->first_child = forker->first_child->next) != start_child );
741 //
742 //      return NULL;
743 //}
744
745
746 static void del_prefork_child( prefork_simple* forker, pid_t pid ) { 
747
748         if( forker->first_child == NULL ) { return; }
749
750         (forker->current_num_children)--;
751         osrfLogDebug( OSRF_LOG_MARK, "Deleting Child: %d", pid );
752
753         prefork_child* start_child = forker->first_child; /* starting point */
754         prefork_child* cur_child        = start_child; /* current pointer */
755         prefork_child* prev_child       = start_child; /* the trailing pointer */
756
757         /* special case where there is only one in the list */
758         if( start_child == start_child->next ) {
759                 if( start_child->pid == pid ) {
760                         forker->first_child = NULL;
761
762                         close( start_child->read_data_fd );
763                         close( start_child->write_data_fd );
764                         close( start_child->read_status_fd );
765                         close( start_child->write_status_fd );
766
767                         prefork_child_free( start_child );
768                 }
769                 return;
770         }
771
772
773         /* special case where the first item in the list needs to be removed */
774         if( start_child->pid == pid ) { 
775
776                 /* find the last one so we can remove the start_child */
777                 do { 
778                         prev_child = cur_child;
779                         cur_child = cur_child->next;
780                 }while( cur_child != start_child );
781
782                 /* now cur_child == start_child */
783                 prev_child->next = cur_child->next;
784                 forker->first_child = prev_child;
785
786                 close( cur_child->read_data_fd );
787                 close( cur_child->write_data_fd );
788                 close( cur_child->read_status_fd );
789                 close( cur_child->write_status_fd );
790
791                 prefork_child_free( cur_child );
792                 return;
793         } 
794
795         do {
796                 prev_child = cur_child;
797                 cur_child = cur_child->next;
798
799                 if( cur_child->pid == pid ) {
800                         prev_child->next = cur_child->next;
801
802                         close( cur_child->read_data_fd );
803                         close( cur_child->write_data_fd );
804                         close( cur_child->read_status_fd );
805                         close( cur_child->write_status_fd );
806
807                         prefork_child_free( cur_child );
808                         return;
809                 }
810
811         } while(cur_child != start_child);
812 }
813
814
815
816
817 static prefork_child* prefork_child_init( 
818         int max_requests, int read_data_fd, int write_data_fd, 
819         int read_status_fd, int write_status_fd ) {
820
821         prefork_child* child = (prefork_child*) safe_malloc(sizeof(prefork_child));
822         child->pid              = 0;
823         child->max_requests             = max_requests;
824         child->read_data_fd             = read_data_fd;
825         child->write_data_fd            = write_data_fd;
826         child->read_status_fd   = read_status_fd;
827         child->write_status_fd  = write_status_fd;
828         child->min_children     = 0;
829         child->available                        = 1;
830         child->appname          = NULL;
831         child->keepalive        = 0;
832         child->next             = NULL;
833
834         return child;
835 }
836
837
838 static int prefork_free( prefork_simple* prefork ) {
839         
840         while( prefork->first_child != NULL ) {
841                 osrfLogInfo( OSRF_LOG_MARK,  "Killing children and sleeping 1 to reap..." );
842                 kill( 0,        SIGKILL );
843                 sleep(1);
844         }
845
846         client_free(prefork->connection);
847         free(prefork->appname);
848         free( prefork );
849         return 1;
850 }
851
852 static int prefork_child_free( prefork_child* child ) { 
853         free(child->appname);
854         close(child->read_data_fd);
855         close(child->write_status_fd);
856         free( child ); 
857         return 1;
858 }
859