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