OpenSRF/src/libstack/osrf_prefork.c

   1 #include "osrf_prefork.h"
   2 #include <signal.h>
   3 #include "osrf_app_session.h"
   4
   5 /* true if we just deleted a child.  This will allow us to make sure we're
   6         not trying to use freed memory */
   7 int child_dead;
   8
   9 int main();
  10 void sigchld_handler( int sig );
  11
  12 int osrf_prefork_run(char* appname) {
  13
  14         if(!appname) fatal_handler("osrf_prefork_run requires an appname to run!");
  15
  16         set_proc_title( "OpenSRF Listener [%s]", appname );
  17
  18         int maxr = 1000;
  19         int maxc = 10;
  20         int minc = 3;
  21
  22         info_handler("Loading config in osrf_forker for app %s", appname);
  23
  24         jsonObject* max_req = osrf_settings_host_value_object("/apps/%s/unix_config/max_requests", appname);
  25         jsonObject* min_children = osrf_settings_host_value_object("/apps/%s/unix_config/min_children", appname);
  26         jsonObject* max_children = osrf_settings_host_value_object("/apps/%s/unix_config/max_children", appname);
  27
  28
  29         if(!max_req) warning_handler("Max requests not defined, assuming 1000");
  30         else maxr = (int) jsonObjectGetNumber(max_req);
  31
  32         if(!min_children) warning_handler("Min children not defined, assuming 3");
  33         else minc = (int) jsonObjectGetNumber(min_children);
  34
  35         if(!max_children) warning_handler("Max children not defined, assuming 10");
  36         else maxc = (int) jsonObjectGetNumber(max_children);
  37
  38         jsonObjectFree(max_req);
  39         jsonObjectFree(min_children);
  40         jsonObjectFree(max_children);
  41         /* --------------------------------------------------- */
  42
  43         char* resc = va_list_to_string("%s_listener", appname);
  44
  45         if(!osrf_system_bootstrap_client_resc( NULL, NULL, resc ))
  46                 fatal_handler("Unable to bootstrap client for osrf_prefork_run()");
  47         free(resc);
  48
  49         prefork_simple* forker = prefork_simple_init(
  50                 osrfSystemGetTransportClient(), maxr, minc, maxc);
  51
  52         forker->appname = strdup(appname);
  53
  54         if(forker == NULL)
  55                 fatal_handler("osrf_prefork_run() failed to create prefork_simple object");
  56
  57         prefork_launch_children(forker);
  58
  59         osrf_prefork_register_routers(appname);
  60
  61         info_handler("Launching osrf_forker for app %s", appname);
  62         prefork_run(forker);
  63
  64         warning_handler("prefork_run() retuned - how??");
  65         prefork_free(forker);
  66         return 0;
  67
  68 }
  69
  70 void osrf_prefork_register_routers( char* appname ) {
  71
  72         osrfStringArray* arr = osrfNewStringArray(4);
  73
  74         int c = osrfConfigGetValueList( NULL, arr, "/routers/router" );
  75         char* routerName = osrfConfigGetValue( NULL, "/router_name" );
  76         transport_client* client = osrfSystemGetTransportClient();
  77
  78         info_handler("router name is %s and we have %d routers to connect to", routerName, c );
  79
  80         while( c ) {
  81                 char* domain = osrfStringArrayGetString(arr, --c);
  82                 if(domain) {
  83
  84                         char* jid = va_list_to_string( "%s@%s/router", routerName, domain );
  85                         info_handler("Registering with router %s", jid );
  86
  87                         transport_message* msg = message_init("registering", NULL, NULL, jid, NULL );
  88                         message_set_router_info( msg, NULL, NULL, appname, "register", 0 );
  89
  90                         client_send_message( client, msg );
  91                         message_free( msg );
  92                         free(jid);
  93                 }
  94         }
  95
  96         free(routerName);
  97         osrfStringArrayFree(arr);
  98 }
  99
 100 void prefork_child_init_hook(prefork_child* child) {
 101
 102         if(!child) return;
 103         info_handler("Child init hook for child %d", child->pid);
 104         char* resc = va_list_to_string("%s_drone",child->appname);
 105         if(!osrf_system_bootstrap_client_resc( NULL, NULL, resc))
 106                 fatal_handler("Unable to bootstrap client for osrf_prefork_run()");
 107         free(resc);
 108
 109         set_proc_title( "OpenSRF Drone [%s]", child->appname );
 110 }
 111
 112 void prefork_child_process_request(prefork_child* child, char* data) {
 113         if( !child ) return;
 114
 115         /* construct the message from the xml */
 116         transport_message* msg = new_message_from_xml( data );
 117
 118         osrfAppSession* session = osrf_stack_transport_handler(msg, child->appname);
 119         if(!session) return;
 120
 121         if( session->stateless && session->state != OSRF_SESSION_CONNECTED ) return;
 122
 123         /* keepalive loop for stateful sessions */
 124
 125                 debug_handler("Entering keepalive loop for session %s", session->session_id );
 126 }
 127
 128
 129 prefork_simple*  prefork_simple_init( transport_client* client,
 130                 int max_requests, int min_children, int max_children ) {
 131
 132         if( min_children > max_children )
 133                 fatal_handler( "min_children (%d) is greater "
 134                                 "than max_children (%d)", min_children, max_children );
 135
 136         if( max_children > ABS_MAX_CHILDREN )
 137                 fatal_handler( "max_children (%d) is greater than ABS_MAX_CHILDREN (%d)",
 138                                 max_children, ABS_MAX_CHILDREN );
 139
 140         /* flesh out the struct */
 141         prefork_simple* prefork = (prefork_simple*) safe_malloc(sizeof(prefork_simple));
 142         prefork->max_requests = max_requests;
 143         prefork->min_children = min_children;
 144         prefork->max_children = max_children;
 145         prefork->first_child = NULL;
 146         prefork->connection = client;
 147
 148         return prefork;
 149 }
 150
 151 prefork_child*  launch_child( prefork_simple* forker ) {
 152
 153         pid_t pid;
 154         int data_fd[2];
 155         int status_fd[2];
 156
 157         /* Set up the data pipes and add the child struct to the parent */
 158         if( pipe(data_fd) < 0 ) /* build the data pipe*/
 159                 fatal_handler( "Pipe making error" );
 160
 161         if( pipe(status_fd) < 0 ) /* build the status pipe */
 162                 fatal_handler( "Pipe making error" );
 163
 164         debug_handler( "Pipes: %d %d %d %d", data_fd[0], data_fd[1], status_fd[0], status_fd[1] );
 165         prefork_child* child = prefork_child_init( forker->max_requests, data_fd[0],
 166                         data_fd[1], status_fd[0], status_fd[1] );
 167
 168         child->appname = strdup(forker->appname);
 169
 170
 171         add_prefork_child( forker, child );
 172
 173         if( (pid=fork()) < 0 ) fatal_handler( "Forking Error" );
 174
 175         if( pid > 0 ) {  /* parent */
 176
 177                 signal(SIGCHLD, sigchld_handler);
 178                 (forker->current_num_children)++;
 179                 child->pid = pid;
 180
 181                 info_handler( "Parent launched %d", pid );
 182                 /* *no* child pipe FD's can be closed or the parent will re-use fd's that
 183                         the children are currently using */
 184                 return child;
 185         }
 186
 187         else { /* child */
 188
 189                 debug_handler("I am  new child with read_data_fd = %d and write_status_fd = %d",
 190                         child->read_data_fd, child->write_status_fd );
 191
 192                 child->pid = getpid();
 193                 close( child->write_data_fd );
 194                 close( child->read_status_fd );
 195
 196                 /* do the initing */
 197                 prefork_child_init_hook(child);
 198
 199                 prefork_child_wait( child );
 200                 exit(0); /* just to be sure */
 201          }
 202         return NULL;
 203 }
 204
 205
 206 void prefork_launch_children( prefork_simple* forker ) {
 207         if(!forker) return;
 208         int c = 0;
 209         while( c++ < forker->min_children )
 210                 launch_child( forker );
 211 }
 212
 213
 214 void sigchld_handler( int sig ) {
 215         signal(SIGCHLD, sigchld_handler);
 216         child_dead = 1;
 217 }
 218
 219
 220 void reap_children( prefork_simple* forker ) {
 221
 222         pid_t child_pid;
 223         int status;
 224
 225         while( (child_pid=waitpid(-1,&status,WNOHANG)) > 0)
 226                 del_prefork_child( forker, child_pid );
 227
 228         /* replenish */
 229         while( forker->current_num_children < forker->min_children )
 230                 launch_child( forker );
 231
 232         child_dead = 0;
 233 }
 234
 235 void prefork_run(prefork_simple* forker) {
 236
 237         if( forker->first_child == NULL )
 238                 return;
 239
 240         transport_message* cur_msg = NULL;
 241
 242
 243         while(1) {
 244
 245                 if( forker->first_child == NULL ) {/* no more children */
 246                         warning_handler("No more children..." );
 247                         return;
 248                 }
 249
 250                 debug_handler("Forker going into wait for data...");
 251                 cur_msg = client_recv( forker->connection, -1 );
 252
 253                 //fprintf(stderr, "Got Data %f\n", get_timestamp_millis() );
 254
 255                 if( cur_msg == NULL ) continue;
 256
 257                 int honored = 0;        /* true if we've serviced the request */
 258
 259                 while( ! honored ) {
 260
 261                         check_children( forker );
 262
 263                         debug_handler( "Server received inbound data" );
 264                         int k;
 265                         prefork_child* cur_child = forker->first_child;
 266
 267                         /* Look for an available child */
 268                         for( k = 0; k < forker->current_num_children; k++ ) {
 269
 270                                 debug_handler("Searching for available child. cur_child->pid = %d", cur_child->pid );
 271                                 debug_handler("Current num children %d and loop %d", forker->current_num_children, k);
 272
 273                                 if( cur_child->available ) {
 274                                         debug_handler( "sending data to %d", cur_child->pid );
 275
 276                                         message_prepare_xml( cur_msg );
 277                                         char* data = cur_msg->msg_xml;
 278                                         if( ! data || strlen(data) < 1 ) break;
 279
 280                                         cur_child->available = 0;
 281                                         debug_handler( "Writing to child fd %d", cur_child->write_data_fd );
 282
 283                                         int written = 0;
 284                                         //fprintf(stderr, "Writing Data %f\n", get_timestamp_millis() );
 285                                         if( (written = write( cur_child->write_data_fd, data, strlen(data) + 1 )) < 0 ) {
 286                                                 warning_handler("Write returned error %d", errno);
 287                                                 cur_child = cur_child->next;
 288                                                 continue;
 289                                         }
 290
 291                                         //fprintf(stderr, "Wrote %d bytes to child\n", written);
 292
 293                                         forker->first_child = cur_child->next;
 294                                         honored = 1;
 295                                         break;
 296                                 } else
 297                                         cur_child = cur_child->next;
 298                         }
 299
 300                         /* if none available, add a new child if we can */
 301                         if( ! honored ) {
 302                                 debug_handler("Not enough children, attempting to add...");
 303                                 if( forker->current_num_children < forker->max_children ) {
 304                                         debug_handler( "Launching new child with current_num = %d",
 305                                                         forker->current_num_children );
 306
 307                                         prefork_child* new_child = launch_child( forker );
 308                                         message_prepare_xml( cur_msg );
 309                                         char* data = cur_msg->msg_xml;
 310                                         if( ! data || strlen(data) < 1 ) break;
 311                                         new_child->available = 0;
 312                                         debug_handler( "sending data to %d", new_child->pid );
 313                                         debug_handler( "Writing to new child fd %d", new_child->write_data_fd );
 314                                         write( new_child->write_data_fd, data, strlen(data) + 1 );
 315                                         forker->first_child = new_child->next;
 316                                         honored = 1;
 317                                 }
 318                         }
 319
 320                         if( !honored ) {
 321                                 warning_handler( "No children available, sleeping and looping..." );
 322                                 usleep( 50000 ); /* 50 milliseconds */
 323                         }
 324
 325                         if( child_dead )
 326                                 reap_children(forker);
 327
 328
 329                         //fprintf(stderr, "Parent done with request %f\n", get_timestamp_millis() );
 330
 331                 } // honored?
 332
 333                 message_free( cur_msg );
 334
 335         } /* top level listen loop */
 336
 337 }
 338
 339
 340 void check_children( prefork_simple* forker ) {
 341
 342         //check_begin:
 343
 344         int select_ret;
 345         fd_set read_set;
 346         FD_ZERO(&read_set);
 347         int max_fd = 0;
 348         int n;
 349
 350         struct timeval tv;
 351         tv.tv_sec       = 0;
 352         tv.tv_usec      = 0;
 353
 354         if( child_dead )
 355                 reap_children(forker);
 356
 357         prefork_child* cur_child = forker->first_child;
 358
 359         int i;
 360         for( i = 0; i!= forker->current_num_children; i++ ) {
 361
 362                 if( cur_child->read_status_fd > max_fd )
 363                         max_fd = cur_child->read_status_fd;
 364                 FD_SET( cur_child->read_status_fd, &read_set );
 365                 cur_child = cur_child->next;
 366         }
 367
 368         FD_CLR(0,&read_set);/* just to be sure */
 369
 370         if( (select_ret=select( max_fd + 1 , &read_set, NULL, NULL, &tv)) == -1 ) {
 371                 warning_handler( "Select returned error %d on check_children", errno );
 372         }
 373
 374         if( select_ret == 0 )
 375                 return;
 376
 377         /* see if one of a child has told us it's done */
 378         cur_child = forker->first_child;
 379         int j;
 380         int num_handled = 0;
 381         for( j = 0; j!= forker->current_num_children && num_handled < select_ret ; j++ ) {
 382
 383                 if( FD_ISSET( cur_child->read_status_fd, &read_set ) ) {
 384                         //printf( "Server received status from a child %d\n", cur_child->pid );
 385                         debug_handler( "Server received status from a child %d", cur_child->pid );
 386
 387                         num_handled++;
 388
 389                         /* now suck off the data */
 390                         char buf[64];
 391                         memset( buf, 0, 64);
 392                         if( (n=read(cur_child->read_status_fd, buf, 63))  < 0 ) {
 393                                 warning_handler("Read error afer select in child status read with errno %d", errno);
 394                         }
 395
 396                         debug_handler( "Read %d bytes from status buffer: %s", n, buf );
 397                         cur_child->available = 1;
 398                 }
 399                 cur_child = cur_child->next;
 400         }
 401
 402 }
 403
 404
 405 void prefork_child_wait( prefork_child* child ) {
 406
 407         int i,n;
 408         growing_buffer* gbuf = buffer_init( READ_BUFSIZE );
 409         char buf[READ_BUFSIZE];
 410         memset( buf, 0, READ_BUFSIZE );
 411
 412         for( i = 0; i!= child->max_requests; i++ ) {
 413
 414                 n = -1;
 415                 clr_fl(child->read_data_fd, O_NONBLOCK );
 416                 while( (n=read(child->read_data_fd, buf, READ_BUFSIZE-1)) > 0 ) {
 417                         buffer_add( gbuf, buf );
 418                         memset( buf, 0, READ_BUFSIZE );
 419
 420                         //fprintf(stderr, "Child read %d bytes\n", n);
 421
 422                         if( n == READ_BUFSIZE ) {
 423                                 //fprintf(stderr, "We read READ_BUFSIZE data....\n");
 424                                 /* XXX */
 425                                 /* either we have exactly READ_BUFSIZE data,
 426                                         or there's more waiting that we need to grab*/
 427                                 /* must set to non-block for reading more */
 428                         } else {
 429                                 //fprintf(stderr, "Read Data %f\n", get_timestamp_millis() );
 430                                 prefork_child_process_request(child, gbuf->buf);
 431                                 buffer_reset( gbuf );
 432                                 break;
 433                         }
 434                 }
 435
 436                 if( n < 0 ) {
 437                         warning_handler( "Child read returned error with errno %d", errno );
 438                         break;
 439                 }
 440
 441                 if( i < child->max_requests - 1 )
 442                         write( child->write_status_fd, "available" /*less than 64 bytes*/, 9 );
 443         }
 444
 445         buffer_free(gbuf);
 446
 447         debug_handler("Child exiting...[%d]", getpid() );
 448
 449         exit(0);
 450 }
 451
 452
 453 void add_prefork_child( prefork_simple* forker, prefork_child* child ) {
 454
 455         if( forker->first_child == NULL ) {
 456                 forker->first_child = child;
 457                 child->next = child;
 458                 return;
 459         }
 460
 461         /* we put the child in as the last because, regardless,
 462                 we have to do the DLL splice dance, and this is the
 463            simplest way */
 464
 465         prefork_child* start_child = forker->first_child;
 466         while(1) {
 467                 if( forker->first_child->next == start_child )
 468                         break;
 469                 forker->first_child = forker->first_child->next;
 470         }
 471
 472         /* here we know that forker->first_child is the last element
 473                 in the list and start_child is the first.  Insert the
 474                 new child between them*/
 475
 476         forker->first_child->next = child;
 477         child->next = start_child;
 478         return;
 479 }
 480
 481 prefork_child* find_prefork_child( prefork_simple* forker, pid_t pid ) {
 482
 483         if( forker->first_child == NULL ) { return NULL; }
 484         prefork_child* start_child = forker->first_child;
 485         do {
 486                 if( forker->first_child->pid == pid )
 487                         return forker->first_child;
 488         } while( (forker->first_child = forker->first_child->next) != start_child );
 489
 490         return NULL;
 491 }
 492
 493
 494 void del_prefork_child( prefork_simple* forker, pid_t pid ) {
 495
 496         if( forker->first_child == NULL ) { return; }
 497
 498         (forker->current_num_children)--;
 499         debug_handler("Deleting Child: %d", pid );
 500
 501         prefork_child* start_child = forker->first_child; /* starting point */
 502         prefork_child* cur_child        = start_child; /* current pointer */
 503         prefork_child* prev_child       = start_child; /* the trailing pointer */
 504
 505         /* special case where there is only one in the list */
 506         if( start_child == start_child->next ) {
 507                 if( start_child->pid == pid ) {
 508                         forker->first_child = NULL;
 509
 510                         close( start_child->read_data_fd );
 511                         close( start_child->write_data_fd );
 512                         close( start_child->read_status_fd );
 513                         close( start_child->write_status_fd );
 514
 515                         prefork_child_free( start_child );
 516                 }
 517                 return;
 518         }
 519
 520
 521         /* special case where the first item in the list needs to be removed */
 522         if( start_child->pid == pid ) {
 523
 524                 /* find the last one so we can remove the start_child */
 525                 do {
 526                         prev_child = cur_child;
 527                         cur_child = cur_child->next;
 528                 }while( cur_child != start_child );
 529
 530                 /* now cur_child == start_child */
 531                 prev_child->next = cur_child->next;
 532                 forker->first_child = prev_child;
 533
 534                 close( cur_child->read_data_fd );
 535                 close( cur_child->write_data_fd );
 536                 close( cur_child->read_status_fd );
 537                 close( cur_child->write_status_fd );
 538
 539                 prefork_child_free( cur_child );
 540                 return;
 541         }
 542
 543         do {
 544                 prev_child = cur_child;
 545                 cur_child = cur_child->next;
 546
 547                 if( cur_child->pid == pid ) {
 548                         prev_child->next = cur_child->next;
 549
 550                         close( cur_child->read_data_fd );
 551                         close( cur_child->write_data_fd );
 552                         close( cur_child->read_status_fd );
 553                         close( cur_child->write_status_fd );
 554
 555                         prefork_child_free( cur_child );
 556                         return;
 557                 }
 558
 559         } while(cur_child != start_child);
 560 }
 561
 562
 563
 564
 565 prefork_child* prefork_child_init(
 566         int max_requests, int read_data_fd, int write_data_fd,
 567         int read_status_fd, int write_status_fd ) {
 568
 569         prefork_child* child = (prefork_child*) safe_malloc(sizeof(prefork_child));
 570         child->max_requests             = max_requests;
 571         child->read_data_fd             = read_data_fd;
 572         child->write_data_fd            = write_data_fd;
 573         child->read_status_fd   = read_status_fd;
 574         child->write_status_fd  = write_status_fd;
 575         child->available                        = 1;
 576
 577         return child;
 578 }
 579
 580
 581 int prefork_free( prefork_simple* prefork ) {
 582
 583         while( prefork->first_child != NULL ) {
 584                 info_handler( "Killing children and sleeping 1 to reap..." );
 585                 kill( 0,        SIGKILL );
 586                 sleep(1);
 587         }
 588
 589         client_free(prefork->connection);
 590         free(prefork->appname);
 591         free( prefork );
 592         return 1;
 593 }
 594
 595 int prefork_child_free( prefork_child* child ) {
 596         free(child->appname);
 597         close(child->read_data_fd);
 598         close(child->write_status_fd);
 599         free( child );
 600         return 1;
 601 }
 602