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