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