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) {
  15                 osrfLogError("osrf_prefork_run requires an appname to run!");
  16                 return -1;
  17         }
  18
  19         set_proc_title( "OpenSRF Listener [%s]", appname );
  20
  21         int maxr = 1000;
  22         int maxc = 10;
  23         int minc = 3;
  24
  25         osrfLogInfo("Loading config in osrf_forker for app %s", appname);
  26
  27         jsonObject* max_req = osrf_settings_host_value_object("/apps/%s/unix_config/max_requests", appname);
  28         jsonObject* min_children = osrf_settings_host_value_object("/apps/%s/unix_config/min_children", appname);
  29         jsonObject* max_children = osrf_settings_host_value_object("/apps/%s/unix_config/max_children", appname);
  30
  31
  32         if(!max_req) osrfLogWarning("Max requests not defined, assuming 1000");
  33         else maxr = (int) jsonObjectGetNumber(max_req);
  34
  35         if(!min_children) osrfLogWarning("Min children not defined, assuming 3");
  36         else minc = (int) jsonObjectGetNumber(min_children);
  37
  38         if(!max_children) osrfLogWarning("Max children not defined, assuming 10");
  39         else maxc = (int) jsonObjectGetNumber(max_children);
  40
  41         jsonObjectFree(max_req);
  42         jsonObjectFree(min_children);
  43         jsonObjectFree(max_children);
  44         /* --------------------------------------------------- */
  45
  46         char* resc = va_list_to_string("%s_listener", appname);
  47
  48         if(!osrf_system_bootstrap_client_resc( NULL, NULL, resc )) {
  49                 osrfLogError("Unable to bootstrap client for osrf_prefork_run()");
  50                 free(resc);
  51                 return -1;
  52         }
  53
  54         free(resc);
  55
  56         prefork_simple* forker = prefork_simple_init(
  57                 osrfSystemGetTransportClient(), maxr, minc, maxc);
  58
  59         forker->appname = strdup(appname);
  60
  61         if(forker == NULL) {
  62                 osrfLogError("osrf_prefork_run() failed to create prefork_simple object");
  63                 return -1;
  64         }
  65
  66         prefork_launch_children(forker);
  67
  68         osrf_prefork_register_routers(appname);
  69
  70         osrfLogInfo("Launching osrf_forker for app %s", appname);
  71         prefork_run(forker);
  72
  73         osrfLogWarning("prefork_run() retuned - how??");
  74         prefork_free(forker);
  75         return 0;
  76
  77 }
  78
  79 void osrf_prefork_register_routers( char* appname ) {
  80
  81         osrfStringArray* arr = osrfNewStringArray(4);
  82
  83         int c = osrfConfigGetValueList( NULL, arr, "/routers/router" );
  84         char* routerName = osrfConfigGetValue( NULL, "/router_name" );
  85         transport_client* client = osrfSystemGetTransportClient();
  86
  87         osrfLogInfo("router name is %s and we have %d routers to connect to", routerName, c );
  88
  89         while( c ) {
  90                 char* domain = osrfStringArrayGetString(arr, --c);
  91                 if(domain) {
  92
  93                         char* jid = va_list_to_string( "%s@%s/router", routerName, domain );
  94                         osrfLogInfo("Registering with router %s", jid );
  95
  96                         transport_message* msg = message_init("registering", NULL, NULL, jid, NULL );
  97                         message_set_router_info( msg, NULL, NULL, appname, "register", 0 );
  98
  99                         client_send_message( client, msg );
 100                         message_free( msg );
 101                         free(jid);
 102                 }
 103         }
 104
 105         free(routerName);
 106         osrfStringArrayFree(arr);
 107 }
 108
 109 void prefork_child_init_hook(prefork_child* child) {
 110
 111         if(!child) return;
 112         osrfLogInfo("Child init hook for child %d", child->pid);
 113         char* resc = va_list_to_string("%s_drone",child->appname);
 114
 115         if(!osrf_system_bootstrap_client_resc( NULL, NULL, resc)) {
 116                 osrfLogError("Unable to bootstrap client for osrf_prefork_run()");
 117                 free(resc);
 118                 return;
 119         }
 120
 121         free(resc);
 122
 123         set_proc_title( "OpenSRF Drone [%s]", child->appname );
 124 }
 125
 126 void prefork_child_process_request(prefork_child* child, char* data) {
 127         if( !child ) return;
 128
 129         /* construct the message from the xml */
 130         transport_message* msg = new_message_from_xml( data );
 131
 132         osrfAppSession* session = osrf_stack_transport_handler(msg, child->appname);
 133         if(!session) return;
 134
 135         if( session->stateless && session->state != OSRF_SESSION_CONNECTED ) {
 136                 osrfAppSessionFree( session );
 137                 return;
 138         }
 139
 140         /* keepalive loop for stateful sessions */
 141
 142                 osrfLogDebug("Entering keepalive loop for session %s", session->session_id );
 143 }
 144
 145
 146 prefork_simple*  prefork_simple_init( transport_client* client,
 147                 int max_requests, int min_children, int max_children ) {
 148
 149         if( min_children > max_children ) {
 150                 osrfLogError( "min_children (%d) is greater "
 151                                 "than max_children (%d)", min_children, max_children );
 152                 return NULL;
 153         }
 154
 155         if( max_children > ABS_MAX_CHILDREN ) {
 156                 osrfLogError( "max_children (%d) is greater than ABS_MAX_CHILDREN (%d)",
 157                                 max_children, ABS_MAX_CHILDREN );
 158                 return NULL;
 159         }
 160
 161         /* flesh out the struct */
 162         prefork_simple* prefork = (prefork_simple*) safe_malloc(sizeof(prefork_simple));
 163         prefork->max_requests = max_requests;
 164         prefork->min_children = min_children;
 165         prefork->max_children = max_children;
 166         prefork->first_child = NULL;
 167         prefork->connection = client;
 168
 169         return prefork;
 170 }
 171
 172 prefork_child*  launch_child( prefork_simple* forker ) {
 173
 174         pid_t pid;
 175         int data_fd[2];
 176         int status_fd[2];
 177
 178         /* Set up the data pipes and add the child struct to the parent */
 179         if( pipe(data_fd) < 0 ) { /* build the data pipe*/
 180                 osrfLogError( "Pipe making error" );
 181                 return NULL;
 182         }
 183
 184         if( pipe(status_fd) < 0 ) {/* build the status pipe */
 185                 osrfLogError( "Pipe making error" );
 186                 return NULL;
 187         }
 188
 189         osrfLogDebug( "Pipes: %d %d %d %d", data_fd[0], data_fd[1], status_fd[0], status_fd[1] );
 190         prefork_child* child = prefork_child_init( forker->max_requests, data_fd[0],
 191                         data_fd[1], status_fd[0], status_fd[1] );
 192
 193         child->appname = strdup(forker->appname);
 194
 195
 196         add_prefork_child( forker, child );
 197
 198         if( (pid=fork()) < 0 ) {
 199                 osrfLogError( "Forking Error" );
 200                 return NULL;
 201         }
 202
 203         if( pid > 0 ) {  /* parent */
 204
 205                 signal(SIGCHLD, sigchld_handler);
 206                 (forker->current_num_children)++;
 207                 child->pid = pid;
 208
 209                 osrfLogInfo( "Parent launched %d", pid );
 210                 /* *no* child pipe FD's can be closed or the parent will re-use fd's that
 211                         the children are currently using */
 212                 return child;
 213         }
 214
 215         else { /* child */
 216
 217                 osrfLogDebug("I am  new child with read_data_fd = %d and write_status_fd = %d",
 218                         child->read_data_fd, child->write_status_fd );
 219
 220                 child->pid = getpid();
 221                 close( child->write_data_fd );
 222                 close( child->read_status_fd );
 223
 224                 /* do the initing */
 225                 prefork_child_init_hook(child);
 226
 227                 prefork_child_wait( child );
 228                 exit(0); /* just to be sure */
 229          }
 230         return NULL;
 231 }
 232
 233
 234 void prefork_launch_children( prefork_simple* forker ) {
 235         if(!forker) return;
 236         int c = 0;
 237         while( c++ < forker->min_children )
 238                 launch_child( forker );
 239 }
 240
 241
 242 void sigchld_handler( int sig ) {
 243         signal(SIGCHLD, sigchld_handler);
 244         child_dead = 1;
 245 }
 246
 247
 248 void reap_children( prefork_simple* forker ) {
 249
 250         pid_t child_pid;
 251         int status;
 252
 253         while( (child_pid=waitpid(-1,&status,WNOHANG)) > 0)
 254                 del_prefork_child( forker, child_pid );
 255
 256         /* replenish */
 257         while( forker->current_num_children < forker->min_children )
 258                 launch_child( forker );
 259
 260         child_dead = 0;
 261 }
 262
 263 void prefork_run(prefork_simple* forker) {
 264
 265         if( forker->first_child == NULL )
 266                 return;
 267
 268         transport_message* cur_msg = NULL;
 269
 270
 271         while(1) {
 272
 273                 if( forker->first_child == NULL ) {/* no more children */
 274                         osrfLogWarning("No more children..." );
 275                         return;
 276                 }
 277
 278                 osrfLogDebug("Forker going into wait for data...");
 279                 cur_msg = client_recv( forker->connection, -1 );
 280
 281                 //fprintf(stderr, "Got Data %f\n", get_timestamp_millis() );
 282
 283                 if( cur_msg == NULL ) continue;
 284
 285                 int honored = 0;        /* true if we've serviced the request */
 286
 287                 while( ! honored ) {
 288
 289                         check_children( forker );
 290
 291                         osrfLogDebug( "Server received inbound data" );
 292                         int k;
 293                         prefork_child* cur_child = forker->first_child;
 294
 295                         /* Look for an available child */
 296                         for( k = 0; k < forker->current_num_children; k++ ) {
 297
 298                                 osrfLogDebug("Searching for available child. cur_child->pid = %d", cur_child->pid );
 299                                 osrfLogDebug("Current num children %d and loop %d", forker->current_num_children, k);
 300
 301                                 if( cur_child->available ) {
 302                                         osrfLogDebug( "sending data to %d", cur_child->pid );
 303
 304                                         message_prepare_xml( cur_msg );
 305                                         char* data = cur_msg->msg_xml;
 306                                         if( ! data || strlen(data) < 1 ) break;
 307
 308                                         cur_child->available = 0;
 309                                         osrfLogDebug( "Writing to child fd %d", cur_child->write_data_fd );
 310
 311                                         int written = 0;
 312                                         //fprintf(stderr, "Writing Data %f\n", get_timestamp_millis() );
 313                                         if( (written = write( cur_child->write_data_fd, data, strlen(data) + 1 )) < 0 ) {
 314                                                 osrfLogWarning("Write returned error %d", errno);
 315                                                 cur_child = cur_child->next;
 316                                                 continue;
 317                                         }
 318
 319                                         //fprintf(stderr, "Wrote %d bytes to child\n", written);
 320
 321                                         forker->first_child = cur_child->next;
 322                                         honored = 1;
 323                                         break;
 324                                 } else
 325                                         cur_child = cur_child->next;
 326                         }
 327
 328                         /* if none available, add a new child if we can */
 329                         if( ! honored ) {
 330                                 osrfLogDebug("Not enough children, attempting to add...");
 331                                 if( forker->current_num_children < forker->max_children ) {
 332                                         osrfLogDebug( "Launching new child with current_num = %d",
 333                                                         forker->current_num_children );
 334
 335                                         prefork_child* new_child = launch_child( forker );
 336                                         message_prepare_xml( cur_msg );
 337                                         char* data = cur_msg->msg_xml;
 338                                         if( ! data || strlen(data) < 1 ) break;
 339                                         new_child->available = 0;
 340                                         osrfLogDebug( "sending data to %d", new_child->pid );
 341                                         osrfLogDebug( "Writing to new child fd %d", new_child->write_data_fd );
 342                                         write( new_child->write_data_fd, data, strlen(data) + 1 );
 343                                         forker->first_child = new_child->next;
 344                                         honored = 1;
 345                                 }
 346                         }
 347
 348                         if( !honored ) {
 349                                 osrfLogWarning( "No children available, sleeping and looping..." );
 350                                 usleep( 50000 ); /* 50 milliseconds */
 351                         }
 352
 353                         if( child_dead )
 354                                 reap_children(forker);
 355
 356
 357                         //fprintf(stderr, "Parent done with request %f\n", get_timestamp_millis() );
 358
 359                 } // honored?
 360
 361                 message_free( cur_msg );
 362
 363         } /* top level listen loop */
 364
 365 }
 366
 367
 368 void check_children( prefork_simple* forker ) {
 369
 370         //check_begin:
 371
 372         int select_ret;
 373         fd_set read_set;
 374         FD_ZERO(&read_set);
 375         int max_fd = 0;
 376         int n;
 377
 378         struct timeval tv;
 379         tv.tv_sec       = 0;
 380         tv.tv_usec      = 0;
 381
 382         if( child_dead )
 383                 reap_children(forker);
 384
 385         prefork_child* cur_child = forker->first_child;
 386
 387         int i;
 388         for( i = 0; i!= forker->current_num_children; i++ ) {
 389
 390                 if( cur_child->read_status_fd > max_fd )
 391                         max_fd = cur_child->read_status_fd;
 392                 FD_SET( cur_child->read_status_fd, &read_set );
 393                 cur_child = cur_child->next;
 394         }
 395
 396         FD_CLR(0,&read_set);/* just to be sure */
 397
 398         if( (select_ret=select( max_fd + 1 , &read_set, NULL, NULL, &tv)) == -1 ) {
 399                 osrfLogWarning( "Select returned error %d on check_children", errno );
 400         }
 401
 402         if( select_ret == 0 )
 403                 return;
 404
 405         /* see if one of a child has told us it's done */
 406         cur_child = forker->first_child;
 407         int j;
 408         int num_handled = 0;
 409         for( j = 0; j!= forker->current_num_children && num_handled < select_ret ; j++ ) {
 410
 411                 if( FD_ISSET( cur_child->read_status_fd, &read_set ) ) {
 412                         //printf( "Server received status from a child %d\n", cur_child->pid );
 413                         osrfLogDebug( "Server received status from a child %d", cur_child->pid );
 414
 415                         num_handled++;
 416
 417                         /* now suck off the data */
 418                         char buf[64];
 419                         memset( buf, 0, 64);
 420                         if( (n=read(cur_child->read_status_fd, buf, 63))  < 0 ) {
 421                                 osrfLogWarning("Read error afer select in child status read with errno %d", errno);
 422                         }
 423
 424                         osrfLogDebug( "Read %d bytes from status buffer: %s", n, buf );
 425                         cur_child->available = 1;
 426                 }
 427                 cur_child = cur_child->next;
 428         }
 429
 430 }
 431
 432
 433 void prefork_child_wait( prefork_child* child ) {
 434
 435         int i,n;
 436         growing_buffer* gbuf = buffer_init( READ_BUFSIZE );
 437         char buf[READ_BUFSIZE];
 438         memset( buf, 0, READ_BUFSIZE );
 439
 440         for( i = 0; i!= child->max_requests; i++ ) {
 441
 442                 n = -1;
 443                 clr_fl(child->read_data_fd, O_NONBLOCK );
 444                 while( (n=read(child->read_data_fd, buf, READ_BUFSIZE-1)) > 0 ) {
 445                         buffer_add( gbuf, buf );
 446                         memset( buf, 0, READ_BUFSIZE );
 447
 448                         //fprintf(stderr, "Child read %d bytes\n", n);
 449
 450                         if( n == READ_BUFSIZE ) {
 451                                 //fprintf(stderr, "We read READ_BUFSIZE data....\n");
 452                                 /* XXX */
 453                                 /* either we have exactly READ_BUFSIZE data,
 454                                         or there's more waiting that we need to grab*/
 455                                 /* must set to non-block for reading more */
 456                         } else {
 457                                 //fprintf(stderr, "Read Data %f\n", get_timestamp_millis() );
 458                                 prefork_child_process_request(child, gbuf->buf);
 459                                 buffer_reset( gbuf );
 460                                 break;
 461                         }
 462                 }
 463
 464                 if( n < 0 ) {
 465                         osrfLogWarning( "Child read returned error with errno %d", errno );
 466                         break;
 467                 }
 468
 469                 if( i < child->max_requests - 1 )
 470                         write( child->write_status_fd, "available" /*less than 64 bytes*/, 9 );
 471         }
 472
 473         buffer_free(gbuf);
 474
 475         osrfLogDebug("Child exiting...[%d]", getpid() );
 476
 477         exit(0);
 478 }
 479
 480
 481 void add_prefork_child( prefork_simple* forker, prefork_child* child ) {
 482
 483         if( forker->first_child == NULL ) {
 484                 forker->first_child = child;
 485                 child->next = child;
 486                 return;
 487         }
 488
 489         /* we put the child in as the last because, regardless,
 490                 we have to do the DLL splice dance, and this is the
 491            simplest way */
 492
 493         prefork_child* start_child = forker->first_child;
 494         while(1) {
 495                 if( forker->first_child->next == start_child )
 496                         break;
 497                 forker->first_child = forker->first_child->next;
 498         }
 499
 500         /* here we know that forker->first_child is the last element
 501                 in the list and start_child is the first.  Insert the
 502                 new child between them*/
 503
 504         forker->first_child->next = child;
 505         child->next = start_child;
 506         return;
 507 }
 508
 509 prefork_child* find_prefork_child( prefork_simple* forker, pid_t pid ) {
 510
 511         if( forker->first_child == NULL ) { return NULL; }
 512         prefork_child* start_child = forker->first_child;
 513         do {
 514                 if( forker->first_child->pid == pid )
 515                         return forker->first_child;
 516         } while( (forker->first_child = forker->first_child->next) != start_child );
 517
 518         return NULL;
 519 }
 520
 521
 522 void del_prefork_child( prefork_simple* forker, pid_t pid ) {
 523
 524         if( forker->first_child == NULL ) { return; }
 525
 526         (forker->current_num_children)--;
 527         osrfLogDebug("Deleting Child: %d", pid );
 528
 529         prefork_child* start_child = forker->first_child; /* starting point */
 530         prefork_child* cur_child        = start_child; /* current pointer */
 531         prefork_child* prev_child       = start_child; /* the trailing pointer */
 532
 533         /* special case where there is only one in the list */
 534         if( start_child == start_child->next ) {
 535                 if( start_child->pid == pid ) {
 536                         forker->first_child = NULL;
 537
 538                         close( start_child->read_data_fd );
 539                         close( start_child->write_data_fd );
 540                         close( start_child->read_status_fd );
 541                         close( start_child->write_status_fd );
 542
 543                         prefork_child_free( start_child );
 544                 }
 545                 return;
 546         }
 547
 548
 549         /* special case where the first item in the list needs to be removed */
 550         if( start_child->pid == pid ) {
 551
 552                 /* find the last one so we can remove the start_child */
 553                 do {
 554                         prev_child = cur_child;
 555                         cur_child = cur_child->next;
 556                 }while( cur_child != start_child );
 557
 558                 /* now cur_child == start_child */
 559                 prev_child->next = cur_child->next;
 560                 forker->first_child = prev_child;
 561
 562                 close( cur_child->read_data_fd );
 563                 close( cur_child->write_data_fd );
 564                 close( cur_child->read_status_fd );
 565                 close( cur_child->write_status_fd );
 566
 567                 prefork_child_free( cur_child );
 568                 return;
 569         }
 570
 571         do {
 572                 prev_child = cur_child;
 573                 cur_child = cur_child->next;
 574
 575                 if( cur_child->pid == pid ) {
 576                         prev_child->next = cur_child->next;
 577
 578                         close( cur_child->read_data_fd );
 579                         close( cur_child->write_data_fd );
 580                         close( cur_child->read_status_fd );
 581                         close( cur_child->write_status_fd );
 582
 583                         prefork_child_free( cur_child );
 584                         return;
 585                 }
 586
 587         } while(cur_child != start_child);
 588 }
 589
 590
 591
 592
 593 prefork_child* prefork_child_init(
 594         int max_requests, int read_data_fd, int write_data_fd,
 595         int read_status_fd, int write_status_fd ) {
 596
 597         prefork_child* child = (prefork_child*) safe_malloc(sizeof(prefork_child));
 598         child->max_requests             = max_requests;
 599         child->read_data_fd             = read_data_fd;
 600         child->write_data_fd            = write_data_fd;
 601         child->read_status_fd   = read_status_fd;
 602         child->write_status_fd  = write_status_fd;
 603         child->available                        = 1;
 604
 605         return child;
 606 }
 607
 608
 609 int prefork_free( prefork_simple* prefork ) {
 610
 611         while( prefork->first_child != NULL ) {
 612                 osrfLogInfo( "Killing children and sleeping 1 to reap..." );
 613                 kill( 0,        SIGKILL );
 614                 sleep(1);
 615         }
 616
 617         client_free(prefork->connection);
 618         free(prefork->appname);
 619         free( prefork );
 620         return 1;
 621 }
 622
 623 int prefork_child_free( prefork_child* child ) {
 624         free(child->appname);
 625         close(child->read_data_fd);
 626         close(child->write_status_fd);
 627         free( child );
 628         return 1;
 629 }
 630