OpenSRF/src/libstack/osrf_prefork.c

   1 #include "osrf_prefork.h"
   2 #include <signal.h>
   3
   4 /* true if we just deleted a child.  This will allow us to make sure we're
   5         not trying to use freed memory */
   6 int child_dead;
   7
   8 int main();
   9 void sigchld_handler( int sig );
  10
  11 int osrf_prefork_run(char* appname) {
  12
  13         if(!appname) fatal_handler("osrf_prefork_run requires an appname to run!");
  14
  15         int maxr = 1000;
  16         int maxc = 10;
  17         int minc = 3;
  18
  19         info_handler("Loading config in osrf_forker for app %s", appname);
  20
  21         jsonObject* max_req = osrf_settings_host_value_object("/apps/%s/unix_config/max_requests", appname);
  22         jsonObject* min_children = osrf_settings_host_value_object("/apps/%s/unix_config/min_children", appname);
  23         jsonObject* max_children = osrf_settings_host_value_object("/apps/%s/unix_config/max_children", appname);
  24
  25         if(!max_req) warning_handler("Max requests not defined, assuming 1000");
  26         else maxr = (int) jsonObjectGetNumber(max_req);
  27
  28         if(!min_children) warning_handler("Min children not defined, assuming 3");
  29         else minc = (int) jsonObjectGetNumber(min_children);
  30
  31         if(!max_children) warning_handler("Max children not defined, assuming 10");
  32         else maxc = (int) jsonObjectGetNumber(max_children);
  33
  34         jsonObjectFree(max_req);
  35         jsonObjectFree(min_children);
  36         jsonObjectFree(max_children);
  37         /* --------------------------------------------------- */
  38
  39         char* resc = va_list_to_string("%s_listener", appname);
  40
  41         if(!osrf_system_bootstrap_client_resc( NULL, NULL, resc ))
  42                 fatal_handler("Unable to bootstrap client for osrf_prefork_run()");
  43         free(resc);
  44
  45         prefork_simple* forker = prefork_simple_init(
  46                 osrfSystemGetTransportClient(), maxr, minc, maxc);
  47
  48         forker->appname = strdup(appname);
  49
  50         if(forker == NULL)
  51                 fatal_handler("osrf_prefork_run() failed to create prefork_simple object");
  52
  53         prefork_launch_children(forker);
  54
  55         osrf_prefork_register_routers(appname);
  56
  57         info_handler("Launching osrf_forker for app %s", appname);
  58         prefork_run(forker);
  59
  60         warning_handler("prefork_run() retuned - how??");
  61         prefork_free(forker);
  62         return 0;
  63
  64 }
  65
  66 void osrf_prefork_register_routers( char* appname ) {
  67
  68         osrfStringArray* arr = osrfNewStringArray(4);
  69
  70         int c = osrfConfigGetValueList( NULL, arr, "/routers/router" );
  71         char* routerName = osrfConfigGetValue( NULL, "/router_name" );
  72         transport_client* client = osrfSystemGetTransportClient();
  73
  74         info_handler("router name is %s and we have %d routers to connect to", routerName, c );
  75
  76         while( c ) {
  77                 char* domain = osrfStringArrayGetString(arr, --c);
  78                 if(domain) {
  79
  80                         char* jid = va_list_to_string( "%s@%s/router", routerName, domain );
  81                         info_handler("Registering with router %s", jid );
  82
  83                         transport_message* msg = message_init("registering", NULL, NULL, jid, NULL );
  84                         message_set_router_info( msg, NULL, NULL, appname, "register", 0 );
  85
  86                         client_send_message( client, msg );
  87                         message_free( msg );
  88                         free(jid);
  89                 }
  90         }
  91
  92         free(routerName);
  93         osrfStringArrayFree(arr);
  94 }
  95
  96 void prefork_child_init_hook(prefork_child* child) {
  97
  98         if(!child) return;
  99         info_handler("Child init hook for child %d", child->pid);
 100         char* resc = va_list_to_string("%s_drone",child->appname);
 101         if(!osrf_system_bootstrap_client_resc( NULL, NULL, resc))
 102                 fatal_handler("Unable to bootstrap client for osrf_prefork_run()");
 103         free(resc);
 104 }
 105
 106 void prefork_child_process_request(prefork_child* child, char* data) {
 107         if(!child && child->connection) return;
 108
 109         /* construct the message from the xml */
 110         debug_handler("Child %d received data from parent:\n%s\n", child->pid, data);
 111         transport_message* msg = new_message_from_xml( data );
 112
 113         osrf_stack_transport_handler(msg, child->appname);
 114
 115         /*
 116         transport_message* ret_msg = message_init(
 117                         msg->body, msg->subject, msg->thread, msg->sender, NULL );
 118
 119         client_send_message(child->connection, ret_msg);
 120         message_free( ret_msg );
 121
 122         printf("Message body size %d\n", strlen(msg->body));
 123
 124         printf( "Message Info\n" );
 125         printf( "%s\n", msg->sender );
 126         printf( "%s\n", msg->recipient );
 127         printf( "%s\n", msg->thread );
 128         printf( "%s\n", msg->body );
 129         printf( "%s\n", msg->subject );
 130         printf( "%s\n", msg->router_from );
 131         printf( "%d\n", msg->broadcast );
 132
 133         message_free( msg );
 134         */
 135 }
 136
 137
 138 prefork_simple*  prefork_simple_init( transport_client* client,
 139                 int max_requests, int min_children, int max_children ) {
 140
 141         if( min_children > max_children )
 142                 fatal_handler( "min_children (%d) is greater "
 143                                 "than max_children (%d)", min_children, max_children );
 144
 145         if( max_children > ABS_MAX_CHILDREN )
 146                 fatal_handler( "max_children (%d) is greater than ABS_MAX_CHILDREN (%d)",
 147                                 max_children, ABS_MAX_CHILDREN );
 148
 149         /* flesh out the struct */
 150         prefork_simple* prefork = (prefork_simple*) safe_malloc(sizeof(prefork_simple));
 151         prefork->max_requests = max_requests;
 152         prefork->min_children = min_children;
 153         prefork->max_children = max_children;
 154         prefork->first_child = NULL;
 155         prefork->connection = client;
 156
 157         return prefork;
 158 }
 159
 160 prefork_child*  launch_child( prefork_simple* forker ) {
 161
 162         pid_t pid;
 163         int data_fd[2];
 164         int status_fd[2];
 165
 166         /* Set up the data pipes and add the child struct to the parent */
 167         if( pipe(data_fd) < 0 ) /* build the data pipe*/
 168                 fatal_handler( "Pipe making error" );
 169
 170         if( pipe(status_fd) < 0 ) /* build the status pipe */
 171                 fatal_handler( "Pipe making error" );
 172
 173         debug_handler( "Pipes: %d %d %d %d", data_fd[0], data_fd[1], status_fd[0], status_fd[1] );
 174         prefork_child* child = prefork_child_init( forker->max_requests, data_fd[0],
 175                         data_fd[1], status_fd[0], status_fd[1] );
 176
 177         child->appname = strdup(forker->appname);
 178
 179
 180         add_prefork_child( forker, child );
 181
 182         if( (pid=fork()) < 0 ) fatal_handler( "Forking Error" );
 183
 184         if( pid > 0 ) {  /* parent */
 185
 186                 signal(SIGCHLD, sigchld_handler);
 187                 (forker->current_num_children)++;
 188                 child->pid = pid;
 189
 190                 info_handler( "Parent launched %d", pid );
 191                 /* *no* child pipe FD's can be closed or the parent will re-use fd's that
 192                         the children are currently using */
 193                 return child;
 194         }
 195
 196         else { /* child */
 197
 198                 debug_handler("I am  new child with read_data_fd = %d and write_status_fd = %d",
 199                         child->read_data_fd, child->write_status_fd );
 200
 201                 child->pid = getpid();
 202                 close( child->write_data_fd );
 203                 close( child->read_status_fd );
 204
 205                 /* do the initing */
 206                 prefork_child_init_hook(child);
 207
 208                 prefork_child_wait( child );
 209                 exit(0); /* just to be sure */
 210          }
 211         return NULL;
 212 }
 213
 214
 215 void prefork_launch_children( prefork_simple* forker ) {
 216         if(!forker) return;
 217         int c = 0;
 218         while( c++ < forker->min_children )
 219                 launch_child( forker );
 220 }
 221
 222
 223 void sigchld_handler( int sig ) {
 224         signal(SIGCHLD, sigchld_handler);
 225         child_dead = 1;
 226 }
 227
 228
 229 void reap_children( prefork_simple* forker ) {
 230
 231         pid_t child_pid;
 232         int status;
 233
 234         while( (child_pid=waitpid(-1,&status,WNOHANG)) > 0)
 235                 del_prefork_child( forker, child_pid );
 236
 237         /* replenish */
 238         while( forker->current_num_children < forker->min_children )
 239                 launch_child( forker );
 240
 241         child_dead = 0;
 242 }
 243
 244 void prefork_run(prefork_simple* forker) {
 245
 246         if( forker->first_child == NULL )
 247                 return;
 248
 249         transport_message* cur_msg = NULL;
 250
 251         while(1) {
 252
 253                 if( forker->first_child == NULL ) {/* no more children */
 254                         warning_handler("No more children..." );
 255                         return;
 256                 }
 257
 258                 debug_handler("Forker going into wait for data...");
 259                 cur_msg = client_recv( forker->connection, -1 );
 260
 261                 //fprintf(stderr, "Got Data %f\n", get_timestamp_millis() );
 262
 263                 if( cur_msg == NULL ) continue;
 264
 265                 int honored = 0;        /* true if we've serviced the request */
 266
 267                 while( ! honored ) {
 268
 269                         check_children( forker );
 270
 271                         debug_handler( "Server received inbound data" );
 272                         int k;
 273                         prefork_child* cur_child = forker->first_child;
 274
 275                         /* Look for an available child */
 276                         for( k = 0; k < forker->current_num_children; k++ ) {
 277
 278                                 debug_handler("Searching for available child. cur_child->pid = %d", cur_child->pid );
 279                                 debug_handler("Current num children %d and loop %d", forker->current_num_children, k);
 280
 281                                 if( cur_child->available ) {
 282                                         debug_handler( "sending data to %d", cur_child->pid );
 283                                         message_prepare_xml( cur_msg );
 284                                         char* data = cur_msg->msg_xml;
 285                                         if( ! data || strlen(data) < 1 ) break;
 286                                         cur_child->available = 0;
 287                                         debug_handler( "Writing to child fd %d", cur_child->write_data_fd );
 288
 289                                         int written = 0;
 290                                         //fprintf(stderr, "Writing Data %f\n", get_timestamp_millis() );
 291                                         if( (written = write( cur_child->write_data_fd, data, strlen(data) + 1 )) < 0 ) {
 292                                                 warning_handler("Write returned error %d", errno);
 293                                                 cur_child = cur_child->next;
 294                                                 continue;
 295                                         }
 296
 297                                         //fprintf(stderr, "Wrote %d bytes to child\n", written);
 298
 299                                         forker->first_child = cur_child->next;
 300                                         honored = 1;
 301                                         break;
 302                                 } else
 303                                         cur_child = cur_child->next;
 304                         }
 305
 306                         /* if none available, add a new child if we can */
 307                         if( ! honored ) {
 308                                 debug_handler("Not enough children, attempting to add...");
 309                                 if( forker->current_num_children < forker->max_children ) {
 310                                         debug_handler( "Launching new child with current_num = %d",
 311                                                         forker->current_num_children );
 312
 313                                         prefork_child* new_child = launch_child( forker );
 314                                         message_prepare_xml( cur_msg );
 315                                         char* data = cur_msg->msg_xml;
 316                                         if( ! data || strlen(data) < 1 ) break;
 317                                         new_child->available = 0;
 318                                         debug_handler( "sending data to %d", new_child->pid );
 319                                         debug_handler( "Writing to new child fd %d", new_child->write_data_fd );
 320                                         write( new_child->write_data_fd, data, strlen(data) + 1 );
 321                                         forker->first_child = new_child->next;
 322                                         honored = 1;
 323                                 }
 324                         }
 325
 326                         if( !honored ) {
 327                                 warning_handler( "No children available, sleeping and looping..." );
 328                                 usleep( 50000 ); /* 50 milliseconds */
 329                         }
 330
 331                         if( child_dead )
 332                                 reap_children(forker);
 333
 334
 335                         //fprintf(stderr, "Parent done with request %f\n", get_timestamp_millis() );
 336
 337                 } // honored?
 338
 339         } /* top level listen loop */
 340
 341 }
 342
 343
 344 void check_children( prefork_simple* forker ) {
 345
 346         //check_begin:
 347
 348         int select_ret;
 349         fd_set read_set;
 350         FD_ZERO(&read_set);
 351         int max_fd = 0;
 352         int n;
 353
 354         struct timeval tv;
 355         tv.tv_sec       = 0;
 356         tv.tv_usec      = 0;
 357
 358         if( child_dead )
 359                 reap_children(forker);
 360
 361         prefork_child* cur_child = forker->first_child;
 362
 363         int i;
 364         for( i = 0; i!= forker->current_num_children; i++ ) {
 365
 366                 if( cur_child->read_status_fd > max_fd )
 367                         max_fd = cur_child->read_status_fd;
 368                 FD_SET( cur_child->read_status_fd, &read_set );
 369                 cur_child = cur_child->next;
 370         }
 371
 372         FD_CLR(0,&read_set);/* just to be sure */
 373
 374         if( (select_ret=select( max_fd + 1 , &read_set, NULL, NULL, &tv)) == -1 ) {
 375                 warning_handler( "Select returned error %d on check_children", errno );
 376         }
 377
 378         if( select_ret == 0 )
 379                 return;
 380
 381         /* see if one of a child has told us it's done */
 382         cur_child = forker->first_child;
 383         int j;
 384         int num_handled = 0;
 385         for( j = 0; j!= forker->current_num_children && num_handled < select_ret ; j++ ) {
 386
 387                 if( FD_ISSET( cur_child->read_status_fd, &read_set ) ) {
 388                         //printf( "Server received status from a child %d\n", cur_child->pid );
 389                         debug_handler( "Server received status from a child %d", cur_child->pid );
 390
 391                         num_handled++;
 392
 393                         /* now suck off the data */
 394                         char buf[64];
 395                         memset( buf, 0, 64);
 396                         if( (n=read(cur_child->read_status_fd, buf, 63))  < 0 ) {
 397                                 warning_handler("Read error afer select in child status read with errno %d", errno);
 398                         }
 399
 400                         debug_handler( "Read %d bytes from status buffer: %s", n, buf );
 401                         cur_child->available = 1;
 402                 }
 403                 cur_child = cur_child->next;
 404         }
 405
 406 }
 407
 408
 409 void prefork_child_wait( prefork_child* child ) {
 410
 411         int i,n;
 412         growing_buffer* gbuf = buffer_init( READ_BUFSIZE );
 413         char buf[READ_BUFSIZE];
 414         memset( buf, 0, READ_BUFSIZE );
 415
 416         for( i = 0; i!= child->max_requests; i++ ) {
 417
 418                 n = -1;
 419                 clr_fl(child->read_data_fd, O_NONBLOCK );
 420                 while( (n=read(child->read_data_fd, buf, READ_BUFSIZE-1)) > 0 ) {
 421                         buffer_add( gbuf, buf );
 422                         memset( buf, 0, READ_BUFSIZE );
 423
 424                         //fprintf(stderr, "Child read %d bytes\n", n);
 425
 426                         if( n == READ_BUFSIZE ) {
 427                                 //fprintf(stderr, "We read READ_BUFSIZE data....\n");
 428                                 /* XXX */
 429                                 /* either we have exactly READ_BUFSIZE data,
 430                                         or there's more waiting that we need to grab*/
 431                                 /* must set to non-block for reading more */
 432                         } else {
 433                                 //fprintf(stderr, "Read Data %f\n", get_timestamp_millis() );
 434                                 prefork_child_process_request(child, gbuf->buf);
 435                                 buffer_reset( gbuf );
 436                                 break;
 437                         }
 438                 }
 439
 440                 if( n < 0 ) {
 441                         warning_handler( "Child read returned error with errno %d", errno );
 442                         break;
 443                 }
 444
 445                 if( i < child->max_requests - 1 )
 446                         write( child->write_status_fd, "available" /*less than 64 bytes*/, 9 );
 447         }
 448
 449         buffer_free(gbuf);
 450
 451         debug_handler("Child exiting...[%d]", getpid() );
 452
 453         exit(0);
 454 }
 455
 456
 457 void add_prefork_child( prefork_simple* forker, prefork_child* child ) {
 458
 459         if( forker->first_child == NULL ) {
 460                 forker->first_child = child;
 461                 child->next = child;
 462                 return;
 463         }
 464
 465         /* we put the child in as the last because, regardless,
 466                 we have to do the DLL splice dance, and this is the
 467            simplest way */
 468
 469         prefork_child* start_child = forker->first_child;
 470         while(1) {
 471                 if( forker->first_child->next == start_child )
 472                         break;
 473                 forker->first_child = forker->first_child->next;
 474         }
 475
 476         /* here we know that forker->first_child is the last element
 477                 in the list and start_child is the first.  Insert the
 478                 new child between them*/
 479
 480         forker->first_child->next = child;
 481         child->next = start_child;
 482         return;
 483 }
 484
 485 prefork_child* find_prefork_child( prefork_simple* forker, pid_t pid ) {
 486
 487         if( forker->first_child == NULL ) { return NULL; }
 488         prefork_child* start_child = forker->first_child;
 489         do {
 490                 if( forker->first_child->pid == pid )
 491                         return forker->first_child;
 492         } while( (forker->first_child = forker->first_child->next) != start_child );
 493
 494         return NULL;
 495 }
 496
 497
 498 void del_prefork_child( prefork_simple* forker, pid_t pid ) {
 499
 500         if( forker->first_child == NULL ) { return; }
 501
 502         (forker->current_num_children)--;
 503         debug_handler("Deleting Child: %d", pid );
 504
 505         prefork_child* start_child = forker->first_child; /* starting point */
 506         prefork_child* cur_child        = start_child; /* current pointer */
 507         prefork_child* prev_child       = start_child; /* the trailing pointer */
 508
 509         /* special case where there is only one in the list */
 510         if( start_child == start_child->next ) {
 511                 if( start_child->pid == pid ) {
 512                         forker->first_child = NULL;
 513
 514                         close( start_child->read_data_fd );
 515                         close( start_child->write_data_fd );
 516                         close( start_child->read_status_fd );
 517                         close( start_child->write_status_fd );
 518
 519                         prefork_child_free( start_child );
 520                 }
 521                 return;
 522         }
 523
 524
 525         /* special case where the first item in the list needs to be removed */
 526         if( start_child->pid == pid ) {
 527
 528                 /* find the last one so we can remove the start_child */
 529                 do {
 530                         prev_child = cur_child;
 531                         cur_child = cur_child->next;
 532                 }while( cur_child != start_child );
 533
 534                 /* now cur_child == start_child */
 535                 prev_child->next = cur_child->next;
 536                 forker->first_child = prev_child;
 537
 538                 close( cur_child->read_data_fd );
 539                 close( cur_child->write_data_fd );
 540                 close( cur_child->read_status_fd );
 541                 close( cur_child->write_status_fd );
 542
 543                 prefork_child_free( cur_child );
 544                 return;
 545         }
 546
 547         do {
 548                 prev_child = cur_child;
 549                 cur_child = cur_child->next;
 550
 551                 if( cur_child->pid == pid ) {
 552                         prev_child->next = cur_child->next;
 553
 554                         close( cur_child->read_data_fd );
 555                         close( cur_child->write_data_fd );
 556                         close( cur_child->read_status_fd );
 557                         close( cur_child->write_status_fd );
 558
 559                         prefork_child_free( cur_child );
 560                         return;
 561                 }
 562
 563         } while(cur_child != start_child);
 564 }
 565
 566
 567
 568
 569 prefork_child* prefork_child_init(
 570         int max_requests, int read_data_fd, int write_data_fd,
 571         int read_status_fd, int write_status_fd ) {
 572
 573         prefork_child* child = (prefork_child*) safe_malloc(sizeof(prefork_child));
 574         child->max_requests             = max_requests;
 575         child->read_data_fd             = read_data_fd;
 576         child->write_data_fd            = write_data_fd;
 577         child->read_status_fd   = read_status_fd;
 578         child->write_status_fd  = write_status_fd;
 579         child->available                        = 1;
 580
 581         return child;
 582 }
 583
 584
 585 int prefork_free( prefork_simple* prefork ) {
 586
 587         while( prefork->first_child != NULL ) {
 588                 info_handler( "Killing children and sleeping 1 to reap..." );
 589                 kill( 0,        SIGKILL );
 590                 sleep(1);
 591         }
 592
 593         client_free(prefork->connection);
 594         free(prefork->appname);
 595         free( prefork );
 596         return 1;
 597 }
 598
 599 int prefork_child_free( prefork_child* child ) {
 600         free(child->appname);
 601         close(child->read_data_fd);
 602         close(child->write_status_fd);
 603         free( child );
 604         return 1;
 605 }
 606