Robust/src/Runtime/DSTM/interface/dstmserver.c

   1 /* Coordinator => Machine that initiates the transaction request call for commiting a transaction
   2  * Participant => Machines that host the objects involved in a transaction commit */
   3
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <pthread.h>
   8 #include <netdb.h>
   9 #include <fcntl.h>
  10 #include <errno.h>
  11 #include <string.h>
  12 #include "dstm.h"
  13 #include "mlookup.h"
  14 #include "llookup.h"
  15 #include "threadnotify.h"
  16 #ifdef COMPILER
  17 #include "thread.h"
  18 #endif
  19
  20
  21 #define LISTEN_PORT 2156
  22 #define BACKLOG 10 //max pending connections
  23 #define RECEIVE_BUFFER_SIZE 2048
  24 #define PRE_BUF_SIZE 2048
  25
  26 extern int classsize[];
  27
  28 objstr_t *mainobjstore;
  29 pthread_mutex_t mainobjstore_mutex;
  30 pthread_mutexattr_t mainobjstore_mutex_attr; /* Attribute for lock to make it a recursive lock */
  31
  32 /* This function initializes the main objects store and creates the
  33  * global machine and location lookup table */
  34
  35 int dstmInit(void)
  36 {
  37         mainobjstore = objstrCreate(DEFAULT_OBJ_STORE_SIZE);
  38         /* Initialize attribute for mutex */
  39         pthread_mutexattr_init(&mainobjstore_mutex_attr);
  40         pthread_mutexattr_settype(&mainobjstore_mutex_attr, PTHREAD_MUTEX_RECURSIVE_NP);
  41         pthread_mutex_init(&mainobjstore_mutex, &mainobjstore_mutex_attr);
  42         if (mhashCreate(HASH_SIZE, LOADFACTOR))
  43                 return 1; //failure
  44
  45         if (lhashCreate(HASH_SIZE, LOADFACTOR))
  46                 return 1; //failure
  47
  48         if (notifyhashCreate(N_HASH_SIZE, N_LOADFACTOR))
  49                 return 1; //failure
  50
  51         return 0;
  52 }
  53
  54 /* This function starts the thread to listen on a socket
  55  * for tranaction calls */
  56 void *dstmListen()
  57 {
  58         int listenfd, acceptfd;
  59         struct sockaddr_in my_addr;
  60         struct sockaddr_in client_addr;
  61         socklen_t addrlength = sizeof(struct sockaddr);
  62         pthread_t thread_dstm_accept;
  63         int i;
  64         int setsockflag=1;
  65
  66         listenfd = socket(AF_INET, SOCK_STREAM, 0);
  67         if (listenfd == -1)
  68         {
  69                 perror("socket");
  70                 exit(1);
  71         }
  72
  73         if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &setsockflag, sizeof (setsockflag)) < 0) {
  74           perror("socket");
  75           exit(1);
  76         }
  77 #ifdef MAC
  78         if (setsockopt(listenfd, SOL_SOCKET, SO_NOSIGPIPE, &setsockflag, sizeof (setsockflag)) < 0) {
  79           perror("socket");
  80           exit(1);
  81         }
  82 #endif
  83
  84         my_addr.sin_family = AF_INET;
  85         my_addr.sin_port = htons(LISTEN_PORT);
  86         my_addr.sin_addr.s_addr = INADDR_ANY;
  87         memset(&(my_addr.sin_zero), '\0', 8);
  88
  89         if (bind(listenfd, (struct sockaddr *)&my_addr, addrlength) == -1)
  90         {
  91                 perror("bind");
  92                 exit(1);
  93         }
  94
  95         if (listen(listenfd, BACKLOG) == -1)
  96         {
  97                 perror("listen");
  98                 exit(1);
  99         }
 100
 101         printf("Listening on port %d, fd = %d\n", LISTEN_PORT, listenfd);
 102         while(1)
 103         {
 104           int retval;
 105           acceptfd = accept(listenfd, (struct sockaddr *)&client_addr, &addrlength);
 106           do {
 107             retval=pthread_create(&thread_dstm_accept, NULL, dstmAccept, (void *)acceptfd);
 108           } while(retval!=0);
 109           pthread_detach(thread_dstm_accept);
 110         }
 111 }
 112 /* This function accepts a new connection request, decodes the control message in the connection
 113  * and accordingly calls other functions to process new requests */
 114 void *dstmAccept(void *acceptfd)
 115 {
 116         int val, retval, size;
 117         unsigned int oid;
 118         char buffer[RECEIVE_BUFFER_SIZE], control,ctrl;
 119         char *ptr;
 120         void *srcObj;
 121         objheader_t *h;
 122         trans_commit_data_t transinfo;
 123         unsigned short objType, *versionarry, version;
 124         unsigned int *oidarry, numoid, mid, threadid;
 125
 126         transinfo.objlocked = NULL;
 127         transinfo.objnotfound = NULL;
 128         transinfo.modptr = NULL;
 129         transinfo.numlocked = 0;
 130         transinfo.numnotfound = 0;
 131
 132         /* Receive control messages from other machines */
 133         if((retval = recv((int)acceptfd, &control, sizeof(char), 0)) <= 0) {
 134                 if (retval == 0) {
 135                         pthread_exit(NULL); // Testing connection
 136                 }
 137                 perror("Error in receiving control from coordinator\n");
 138                 pthread_exit(NULL);
 139         }
 140
 141         switch(control) {
 142                 case READ_REQUEST:
 143                         printf("DEBUG -> Recv READ_REQUEST\n");
 144                         /* Read oid requested and search if available */
 145                         if((retval = recv((int)acceptfd, &oid, sizeof(unsigned int), 0)) <= 0) {
 146                                 perror("Error receiving object from cooridnator\n");
 147                                 pthread_exit(NULL);
 148                         }
 149                         if((srcObj = mhashSearch(oid)) == NULL) {
 150                                 printf("Object 0x%x is not found in Main Object Store %s %d\n", oid, __FILE__, __LINE__);
 151                                 pthread_exit(NULL);
 152                         }
 153                         h = (objheader_t *) srcObj;
 154                         GETSIZE(size, h);
 155                         size += sizeof(objheader_t);
 156
 157                         if (h == NULL) {
 158                                 ctrl = OBJECT_NOT_FOUND;
 159                                 if(send((int)acceptfd, &ctrl, sizeof(char), MSG_NOSIGNAL) < sizeof(char)) {
 160                                         perror("Error sending control msg to coordinator\n");
 161                                         pthread_exit(NULL);
 162                                 }
 163                         } else {
 164                                 /* Type */
 165                                 char msg[]={OBJECT_FOUND, 0, 0, 0, 0};
 166                                 *((int *)&msg[1])=size;
 167                                 if(send((int)acceptfd, &msg, sizeof(msg), MSG_NOSIGNAL) < sizeof(msg)) {
 168                                         perror("Error sending size of object to coordinator\n");
 169                                         pthread_exit(NULL);
 170                                 }
 171                                 if(send((int)acceptfd, h, size, MSG_NOSIGNAL) < size) {
 172                                         perror("Error in sending object\n");
 173                                         pthread_exit(NULL);
 174                                 }
 175                         }
 176                         break;
 177
 178                 case READ_MULT_REQUEST:
 179                         printf("DEBUG-> READ_MULT_REQUEST\n");
 180                         break;
 181
 182                 case MOVE_REQUEST:
 183                         printf("DEBUG -> MOVE_REQUEST\n");
 184                         break;
 185
 186                 case MOVE_MULT_REQUEST:
 187                         printf("DEBUG -> MOVE_MULT_REQUEST\n");
 188                         break;
 189
 190                 case TRANS_REQUEST:
 191                         /* Read transaction request */
 192                         printf("DEBUG -> Recv TRANS_REQUEST\n");
 193                         if((val = readClientReq(&transinfo, (int)acceptfd)) != 0) {
 194                                 printf("Error in readClientReq\n");
 195                                 pthread_exit(NULL);
 196                         }
 197                         break;
 198                 case TRANS_PREFETCH:
 199                         printf("DEBUG -> Recv TRANS_PREFETCH\n");
 200                         if((val = prefetchReq((int)acceptfd)) != 0) {
 201                                 printf("Error in transPrefetch\n");
 202                                 pthread_exit(NULL);
 203                         }
 204                         break;
 205                 case START_REMOTE_THREAD:
 206                         retval = recv((int)acceptfd, &oid, sizeof(unsigned int), 0);
 207                         if (retval <= 0)
 208                                 perror("dstmAccept(): error receiving START_REMOTE_THREAD msg");
 209                         else if (retval != sizeof(unsigned int))
 210                                 printf("dstmAccept(): incorrect msg size %d for START_REMOTE_THREAD\n",
 211                                         retval);
 212                         else
 213                         {
 214                                 objType = getObjType(oid);
 215                                 startDSMthread(oid, objType);
 216                         }
 217                         break;
 218
 219                 case THREAD_NOTIFY_REQUEST:
 220                         size = sizeof(unsigned int);
 221                         retval = recv((int)acceptfd, &numoid, size, 0);
 222                         size = (sizeof(unsigned int) + sizeof(unsigned short)) * numoid + 2 * sizeof(unsigned int);
 223                         bzero(&buffer, RECEIVE_BUFFER_SIZE);
 224                         retval = recv((int)acceptfd, &buffer, size, 0);
 225                         oidarry = calloc(numoid, sizeof(unsigned int));
 226                         memcpy(oidarry, buffer, sizeof(unsigned int) * numoid);
 227                         size = sizeof(unsigned int) * numoid;
 228                         versionarry = calloc(numoid, sizeof(unsigned short));
 229                         memcpy(versionarry, buffer+size, sizeof(unsigned short) * numoid);
 230                         size += sizeof(unsigned short) * numoid;
 231                         mid = *((unsigned int *)(buffer+size));
 232                         size += sizeof(unsigned int);
 233                         threadid = *((unsigned int *)(buffer+size));
 234                         processReqNotify(numoid, oidarry, versionarry, mid, threadid);
 235
 236                         break;
 237
 238                 case THREAD_NOTIFY_RESPONSE:
 239                         size = sizeof(unsigned short) + 2 * sizeof(unsigned int);
 240                         bzero(&buffer, RECEIVE_BUFFER_SIZE);
 241                         retval = recv((int)acceptfd, &buffer, size, 0);
 242                         if(retval <= 0)
 243                                 perror("dstmAccept(): error receiving THREAD_NOTIFY_RESPONSE msg");
 244                         else if( retval != 2*sizeof(unsigned int) + sizeof(unsigned short))
 245                                 printf("dstmAccept(): incorrect smsg size %d for THREAD_NOTIFY_RESPONSE msg\n", retval);
 246                         else {
 247                                 oid = *((unsigned int *)buffer);
 248                                 size = sizeof(unsigned int);
 249                                 version = *((unsigned short *)(buffer+size));
 250                                 size += sizeof(unsigned short);
 251                                 threadid = *((unsigned int *)(buffer+size));
 252                                 threadNotify(oid,version,threadid);
 253                         }
 254
 255                         break;
 256
 257                 default:
 258                         printf("DEBUG -> dstmAccept: Error Unknown opcode %d\n", control);
 259         }
 260
 261         /* Close connection */
 262         if (close((int)acceptfd) == -1)
 263                 perror("close");
 264
 265         pthread_exit(NULL);
 266 }
 267
 268 /* This function reads the information available in a transaction request
 269  * and makes a function call to process the request */
 270 int readClientReq(trans_commit_data_t *transinfo, int acceptfd) {
 271         char *ptr;
 272         void *modptr;
 273         unsigned int *oidmod, oid;
 274         fixed_data_t fixed;
 275         objheader_t *headaddr;
 276         int sum = 0, i, N, n, val;
 277
 278         oidmod = NULL;
 279
 280         /* Read fixed_data_t data structure */
 281         N = sizeof(fixed) - 1;
 282         ptr = (char *)&fixed;;
 283         fixed.control = TRANS_REQUEST;
 284         do {
 285                 n = recv((int)acceptfd, (void *) ptr+1+sum, N-sum, 0);
 286                 sum += n;
 287         } while(sum < N && n != 0);
 288
 289         /* Read list of mids */
 290         int mcount = fixed.mcount;
 291         N = mcount * sizeof(unsigned int);
 292         unsigned int listmid[mcount];
 293         ptr = (char *) listmid;
 294         sum = 0;
 295         do {
 296                 n = recv((int)acceptfd, (void *) ptr+sum, N-sum, 0);
 297                 sum += n;
 298         } while(sum < N && n != 0);
 299
 300         /* Read oid and version tuples for those objects that are not modified in the transaction */
 301         int numread = fixed.numread;
 302         N = numread * (sizeof(unsigned int) + sizeof(short));
 303         char objread[N];
 304         if(numread != 0) { //If pile contains more than one object to be read,
 305                           // keep reading all objects
 306                 sum = 0;
 307                 do {
 308                         n = recv((int)acceptfd, (void *) objread, N, 0);
 309                         sum += n;
 310                 } while(sum < N && n != 0);
 311         }
 312
 313         /* Read modified objects */
 314         if(fixed.nummod != 0) {
 315                 if ((modptr = calloc(1, fixed.sum_bytes)) == NULL) {
 316                         printf("calloc error for modified objects %s, %d\n", __FILE__, __LINE__);
 317                         return 1;
 318                 }
 319                 sum = 0;
 320                 do { // Recv the objs that are modified by the Coordinator
 321                         n = recv((int)acceptfd, (char *) modptr+sum, fixed.sum_bytes-sum, 0);
 322                         sum += n;
 323                 } while (sum < fixed.sum_bytes && n != 0);
 324         }
 325
 326         /* Create an array of oids for modified objects */
 327         oidmod = (unsigned int *) calloc(fixed.nummod, sizeof(unsigned int));
 328         if (oidmod == NULL)
 329         {
 330                 printf("calloc error %s, %d\n", __FILE__, __LINE__);
 331                 return 1;
 332         }
 333         ptr = (char *) modptr;
 334         for(i = 0 ; i < fixed.nummod; i++) {
 335           int tmpsize;
 336           headaddr = (objheader_t *) ptr;
 337           oid = OID(headaddr);
 338           oidmod[i] = oid;
 339           GETSIZE(tmpsize, headaddr);
 340           ptr += sizeof(objheader_t) + tmpsize;
 341         }
 342
 343         /*Process the information read */
 344         if((val = processClientReq(&fixed, transinfo, listmid, objread, modptr, oidmod, acceptfd)) != 0) {
 345                 printf("Error in processClientReq %s, %d\n", __FILE__, __LINE__);
 346                 /* Free resources */
 347                 if(oidmod != NULL) {
 348                         free(oidmod);
 349                 }
 350                 return 1;
 351         }
 352
 353         /* Free resources */
 354         if(oidmod != NULL) {
 355                 free(oidmod);
 356         }
 357
 358         return 0;
 359 }
 360
 361 /* This function processes the Coordinator's transaction request using "handleTransReq"
 362  * function and sends a reply to the co-ordinator.
 363  * Following this it also receives a new control message from the co-ordinator and processes this message*/
 364 int processClientReq(fixed_data_t *fixed, trans_commit_data_t *transinfo,
 365                 unsigned int *listmid, char *objread, void *modptr, unsigned int *oidmod, int acceptfd) {
 366         char *ptr, control, sendctrl;
 367         objheader_t *tmp_header;
 368         void *header;
 369         int  i = 0, val, retval;
 370
 371         /* Send reply to the Coordinator */
 372         if((retval = handleTransReq(fixed, transinfo, listmid, objread, modptr,acceptfd)) == 0 ) {
 373                 printf("Handle Trans Req error %s, %d\n", __FILE__, __LINE__);
 374                 return 1;
 375         }
 376
 377         /* Read new control message from Coordiator */
 378         if((retval = recv((int)acceptfd, &control, sizeof(char), 0)) <= 0 ) {
 379                 perror("Error in receiving control message\n");
 380                 return 1;
 381         }
 382
 383         /* Process the new control message */
 384         switch(control) {
 385                 case TRANS_ABORT:
 386                         if (fixed->nummod > 0)
 387                                 free(modptr);
 388                         /* Unlock objects that was locked due to this transaction */
 389                         for(i = 0; i< transinfo->numlocked; i++) {
 390                                 header = mhashSearch(transinfo->objlocked[i]);// find the header address
 391                                 STATUS(((objheader_t *)header)) &= ~(LOCK);
 392                         }
 393
 394                         /* Send ack to Coordinator */
 395                         sendctrl = TRANS_SUCESSFUL;
 396                         if(send((int)acceptfd, &sendctrl, sizeof(char), MSG_NOSIGNAL) < sizeof(char)) {
 397                                 perror("Error sending ACK to coordinator\n");
 398                                 if (transinfo->objlocked != NULL) {
 399                                         free(transinfo->objlocked);
 400                                 }
 401                                 if (transinfo->objnotfound != NULL) {
 402                                         free(transinfo->objnotfound);
 403                                 }
 404
 405                                 return 1;
 406                         }
 407                         ptr = NULL;
 408                         break;
 409
 410                 case TRANS_COMMIT:
 411                         /* Invoke the transCommit process() */
 412                         if((val = transCommitProcess(modptr, oidmod, transinfo->objlocked, fixed->nummod, transinfo->numlocked, (int)acceptfd)) != 0) {
 413                                 printf("Error in transCommitProcess %s, %d\n", __FILE__, __LINE__);
 414                                 /* Free memory */
 415                                 if (transinfo->objlocked != NULL) {
 416                                         free(transinfo->objlocked);
 417                                 }
 418                                 if (transinfo->objnotfound != NULL) {
 419                                         free(transinfo->objnotfound);
 420                                 }
 421                                 return 1;
 422                         }
 423                         break;
 424
 425                 case TRANS_ABORT_BUT_RETRY_COMMIT_WITH_RELOCATING:
 426                         //TODO expect another transrequest from client
 427                         printf("DEBUG -> Recv TRANS_ABORT_BUT_RETRY_COMMIT_WITH_RELOCATING\n");
 428                         break;
 429                 default:
 430                         printf("No response to TRANS_AGREE OR DISAGREE protocol\n");
 431                         //TODO Use fixed.trans_id  TID since Client may have died
 432                         break;
 433         }
 434
 435         /* Free memory */
 436         if (transinfo->objlocked != NULL) {
 437                 free(transinfo->objlocked);
 438         }
 439         if (transinfo->objnotfound != NULL) {
 440                 free(transinfo->objnotfound);
 441         }
 442
 443         return 0;
 444 }
 445
 446 /* This function increments counters while running a voting decision on all objects involved
 447  * in TRANS_REQUEST and If a TRANS_DISAGREE sends the response immediately back to the coordinator */
 448 char handleTransReq(fixed_data_t *fixed, trans_commit_data_t *transinfo, unsigned int *listmid, char *objread, void *modptr, int acceptfd) {
 449         int val, i = 0;
 450         unsigned short version;
 451         char control = 0, *ptr;
 452         unsigned int oid;
 453         unsigned int *oidnotfound, *oidlocked;
 454         void *mobj;
 455         objheader_t *headptr;
 456
 457         /* Counters and arrays to formulate decision on control message to be sent */
 458         oidnotfound = (unsigned int *) calloc(fixed->numread + fixed->nummod, sizeof(unsigned int));
 459         oidlocked = (unsigned int *) calloc(fixed->numread + fixed->nummod, sizeof(unsigned int));
 460         int objnotfound = 0, objlocked = 0;
 461         int v_nomatch = 0, v_matchlock = 0, v_matchnolock = 0;
 462
 463         /* modptr points to the beginning of the object store
 464          * created at the Pariticipant.
 465          * Object store holds the modified objects involved in the transaction request */
 466         ptr = (char *) modptr;
 467
 468         /* Process each oid in the machine pile/ group per thread */
 469         for (i = 0; i < fixed->numread + fixed->nummod; i++) {
 470                 if (i < fixed->numread) {//Objs only read and not modified
 471                         int incr = sizeof(unsigned int) + sizeof(short);// Offset that points to next position in the objread array
 472                         incr *= i;
 473                         oid = *((unsigned int *)(objread + incr));
 474                         incr += sizeof(unsigned int);
 475                         version = *((unsigned short *)(objread + incr));
 476                 } else {//Objs modified
 477                   int tmpsize;
 478                   headptr = (objheader_t *) ptr;
 479                   oid = OID(headptr);
 480                   version = headptr->version;
 481                   GETSIZE(tmpsize, headptr);
 482                   ptr += sizeof(objheader_t) + tmpsize;
 483                 }
 484
 485                 /* Check if object is still present in the machine since the beginning of TRANS_REQUEST */
 486
 487                 if ((mobj = mhashSearch(oid)) == NULL) {/* Obj not found */
 488                         /* Save the oids not found and number of oids not found for later use */
 489                         oidnotfound[objnotfound] = oid;
 490                         objnotfound++;
 491                 } else { /* If Obj found in machine (i.e. has not moved) */
 492                         /* Check if Obj is locked by any previous transaction */
 493                         if ((STATUS(((objheader_t *)mobj)) & LOCK) == LOCK) {
 494                                 if (version == ((objheader_t *)mobj)->version) {      /* If locked then match versions */
 495                                         v_matchlock++;
 496                                 } else {/* If versions don't match ...HARD ABORT */
 497                                         v_nomatch++;
 498                                         /* Send TRANS_DISAGREE to Coordinator */
 499                                         control = TRANS_DISAGREE;
 500                                         if((val = send(acceptfd, &control, sizeof(char), MSG_NOSIGNAL)) < sizeof(char)) {
 501                                                 perror("Error in sending control to the Coordinator\n");
 502                                                 return 0;
 503                                         }
 504                                         return control;
 505                                 }
 506                         } else {/* If Obj is not locked then lock object */
 507                                 STATUS(((objheader_t *)mobj)) |= LOCK;
 508                                 /* Save all object oids that are locked on this machine during this transaction request call */
 509                                 oidlocked[objlocked] = OID(((objheader_t *)mobj));
 510                                 objlocked++;
 511                                 if (version == ((objheader_t *)mobj)->version) { /* Check if versions match */
 512                                         v_matchnolock++;
 513                                 } else { /* If versions don't match ...HARD ABORT */
 514                                         v_nomatch++;
 515                                         control = TRANS_DISAGREE;
 516                                         /* Send TRANS_DISAGREE to Coordinator */
 517                                         if((val = send(acceptfd, &control, sizeof(char), MSG_NOSIGNAL)) < sizeof(char)) {
 518                                                 perror("Error in sending control to the Coordinator\n");
 519                                                 return 0;
 520                                         }
 521                                         if (objlocked > 0) {
 522                                                 STATUS(((objheader_t *)mobj)) &= ~(LOCK);
 523                                                 free(oidlocked);
 524                                         }
 525                                         return control;
 526                                 }
 527                         }
 528                 }
 529         }
 530
 531         /* Decide what control message to send to Coordinator */
 532         if ((val = decideCtrlMessage(fixed, transinfo, &v_matchnolock, &v_matchlock, &v_nomatch, &objnotfound, &objlocked,
 533                                         modptr, oidnotfound, oidlocked, acceptfd)) == 0) {
 534                 printf("Error in decideCtrlMessage %s, %d\n", __FILE__, __LINE__);
 535                 return 0;
 536         }
 537
 538         return val;
 539
 540 }
 541 /* This function decides what control message such as TRANS_AGREE, TRANS_DISAGREE or TRANS_SOFT_ABORT
 542  * to send to Coordinator based on the votes of oids involved in the transaction */
 543 int decideCtrlMessage(fixed_data_t *fixed, trans_commit_data_t *transinfo, int *v_matchnolock, int *v_matchlock,
 544                 int *v_nomatch, int *objnotfound, int *objlocked, void *modptr,
 545                 unsigned int *oidnotfound, unsigned int *oidlocked, int acceptfd) {
 546         int val;
 547         char control = 0;
 548         /* Condition to send TRANS_AGREE */
 549         if(*(v_matchnolock) == fixed->numread + fixed->nummod) {
 550                 control = TRANS_AGREE;
 551                 /* Send control message */
 552                 if((val = send(acceptfd, &control, sizeof(char), MSG_NOSIGNAL)) < sizeof(char)) {
 553                         perror("Error in sending control to Coordinator\n");
 554                         return 0;
 555                 }
 556         }
 557         /* Condition to send TRANS_SOFT_ABORT */
 558         if((*(v_matchlock) > 0 && *(v_nomatch) == 0) || (*(objnotfound) > 0 && *(v_nomatch) == 0)) {
 559                 control = TRANS_SOFT_ABORT;
 560                 char msg[]={TRANS_SOFT_ABORT, 0,0,0,0};
 561                 *((int*)&msg[1])= *(objnotfound);
 562
 563                 /* Send control message */
 564                 if((val = send(acceptfd, &msg, sizeof(msg),MSG_NOSIGNAL)) < sizeof(msg)) {
 565                         perror("Error in sending no of objects that are not found\n");
 566                         return 0;
 567                 }
 568                 /* Send number of oids not found and the missing oids if objects are missing in the machine */
 569                 if(*(objnotfound) != 0) {
 570                         int size = sizeof(unsigned int)* *(objnotfound);
 571                         if((val = send(acceptfd, oidnotfound, size ,MSG_NOSIGNAL)) < size) {
 572                                 perror("Error in sending objects that are not found\n");
 573                                 return 0;
 574                         }
 575                 }
 576         }
 577
 578         /* Fill out the trans_commit_data_t data structure. This is required for a trans commit process
 579          * if Participant receives a TRANS_COMMIT */
 580         transinfo->objlocked = oidlocked;
 581         transinfo->objnotfound = oidnotfound;
 582         transinfo->modptr = modptr;
 583         transinfo->numlocked = *(objlocked);
 584         transinfo->numnotfound = *(objnotfound);
 585
 586         return control;
 587 }
 588
 589 /* This function processes all modified objects involved in a TRANS_COMMIT and updates pointer
 590  * addresses in lookup table and also changes version number
 591  * Sends an ACK back to Coordinator */
 592 int transCommitProcess(void *modptr, unsigned int *oidmod, unsigned int *oidlocked, int nummod, int numlocked, int acceptfd) {
 593         objheader_t *header;
 594         objheader_t *newheader;
 595         int i = 0, offset = 0;
 596         char control;
 597         int tmpsize;
 598
 599         /* Process each modified object saved in the mainobject store */
 600         for(i = 0; i < nummod; i++) {
 601                 if((header = (objheader_t *) mhashSearch(oidmod[i])) == NULL) {
 602                         printf("mhashsearch returns NULL at %s, %d\n", __FILE__, __LINE__);
 603                         return 1;
 604                 }
 605                 GETSIZE(tmpsize,header);
 606                 pthread_mutex_lock(&mainobjstore_mutex);
 607                 memcpy(header, (char *)modptr + offset, tmpsize + sizeof(objheader_t));
 608                 header->version += 1;
 609                 /* If threads are waiting on this object to be updated, notify them */
 610                 if(header->notifylist != NULL) {
 611                         notifyAll(&header->notifylist, OID(header), header->version);
 612                 }
 613                 pthread_mutex_unlock(&mainobjstore_mutex);
 614                 offset += sizeof(objheader_t) + tmpsize;
 615         }
 616
 617         if (nummod > 0)
 618                 free(modptr);
 619
 620         /* Unlock locked objects */
 621         for(i = 0; i < numlocked; i++) {
 622                 if((header = (objheader_t *) mhashSearch(oidlocked[i])) == NULL) {
 623                         printf("mhashsearch returns NULL at %s, %d\n", __FILE__, __LINE__);
 624                         return 1;
 625                 }
 626                 STATUS(header) &= ~(LOCK);
 627         }
 628         //TODO Update location lookup table
 629
 630         /* Send ack to coordinator */
 631         control = TRANS_SUCESSFUL;
 632         if(send((int)acceptfd, &control, sizeof(char), MSG_NOSIGNAL) < sizeof(char)) {
 633                 perror("Error sending ACK to coordinator\n");
 634         }
 635
 636         return 0;
 637 }
 638
 639 /* This function recevies the oid and offset tuples from the Coordinator's prefetch call.
 640  * Looks for the objects to be prefetched in the main object store.
 641  * If objects are not found then record those and if objects are found
 642  * then use offset values to prefetch references to other objects */
 643
 644 int prefetchReq(int acceptfd) {
 645         int i, length, sum, n, numbytes, numoffset, N, size, count = 0;
 646         int isArray = 0, bytesRecvd;
 647         unsigned int oid, index = 0;
 648         unsigned int objoid, myIpAddr;
 649         char *ptr, control, buffer[PRE_BUF_SIZE];
 650         void *mobj;
 651         objheader_t * header;
 652
 653 #ifdef MAC
 654         myIpAddr = getMyIpAddr("en1");
 655 #else
 656         myIpAddr = getMyIpAddr("eth0");
 657 #endif
 658
 659         /* Repeatedly recv the oid and offset pairs sent for prefetch */
 660         while(numbytes = recv((int)acceptfd, &length, sizeof(int), 0) != 0) {
 661                 count++;
 662                 if(length == -1)
 663                         break;
 664                 index = sizeof(unsigned int); // Index starts with sizeof  unsigned int because the
 665                 // first 4 bytes are saved to send the
 666                 // size of the buffer (that is computed at the end of the loop)
 667                 bytesRecvd = 0;
 668                 do {
 669                         bytesRecvd += recv((int)acceptfd, (char *)&oid +bytesRecvd,
 670                                         sizeof(unsigned int) - bytesRecvd, 0);
 671                 } while (bytesRecvd < sizeof(unsigned int));
 672                 numoffset = (length - (sizeof(int) + sizeof(unsigned int)))/ sizeof(short);
 673                 N = numoffset * sizeof(short);
 674                 short offset[numoffset];
 675                 ptr = (char *)&offset;
 676                 sum = 0;
 677                 /* Recv the offset values per oid */
 678                 do {
 679                         n = recv((int)acceptfd, (void *)ptr+sum, N-sum, 0);
 680                         sum += n;
 681                 } while(sum < N && n != 0);
 682
 683                 /* Process each oid */
 684                 if ((mobj = mhashSearch(oid)) == NULL) {/* Obj not found */
 685                         /* Save the oids not found in buffer for later use */
 686                         *(buffer + index) = OBJECT_NOT_FOUND;
 687                         index += sizeof(char);
 688                         *((unsigned int *)(buffer+index)) = oid;
 689                         index += sizeof(unsigned int);
 690                 } else { /* If Obj found in machine (i.e. has not moved) */
 691                         /* send the oid, it's size, it's header and data */
 692                         header = (objheader_t *)mobj;
 693                         GETSIZE(size, header);
 694                         size += sizeof(objheader_t);
 695                         *(buffer + index) = OBJECT_FOUND;
 696                         index += sizeof(char);
 697                         *((unsigned int *)(buffer+index)) = oid;
 698                         index += sizeof(unsigned int);
 699                         *((int *)(buffer+index)) = size;
 700                         index += sizeof(int);
 701                         memcpy(buffer + index, header, size);
 702                         index += size;
 703                         /* Calculate the oid corresponding to the offset value */
 704                         for(i = 0 ; i< numoffset ; i++) {
 705                                 /* Check for arrays  */
 706                                 if(TYPE(header) > NUMCLASSES) {
 707                                         isArray = 1;
 708                                 }
 709                                 if(isArray == 1) {
 710                                         int elementsize = classsize[TYPE(header)];
 711                                         objoid = *((unsigned int *)(((char *)header) + sizeof(objheader_t) + sizeof(struct ArrayObject) + (elementsize*offset[i])));
 712                                 } else {
 713                                         objoid = *((unsigned int *)(((char *)header) + sizeof(objheader_t) + offset[i]));
 714                                 }
 715                                 if((header = mhashSearch(objoid)) == NULL) {
 716                                         /* Obj not found, send oid */
 717                                         *(buffer + index) = OBJECT_NOT_FOUND;
 718                                         index += sizeof(char);
 719                                         *((unsigned int *)(buffer+index)) = objoid;
 720                                         index += sizeof(unsigned int);
 721                                         break;
 722                                 } else {/* Obj Found */
 723                                         /* send the oid, it's size, it's header and data */
 724                                         GETSIZE(size, header);
 725                                         size+=sizeof(objheader_t);
 726                                         *(buffer+index) = OBJECT_FOUND;
 727                                         index += sizeof(char);
 728                                         *((unsigned int *)(buffer+index)) = objoid;
 729                                         index += sizeof(unsigned int);
 730                                         *((int *)(buffer+index)) = size;
 731                                         index += sizeof(int);
 732                                         memcpy(buffer+index, header, size);
 733                                         index += size;
 734                                         isArray = 0;
 735                                         continue;
 736                                 }
 737                         }
 738                 }
 739                 /* Check for overflow in the buffer */
 740                 if (index >= PRE_BUF_SIZE) {
 741                         printf("Char buffer is overflowing\n");
 742                         return 1;
 743                 }
 744                 /* Send Prefetch response control message only once*/
 745                 if(count == 1){
 746                         control = TRANS_PREFETCH_RESPONSE;
 747                         if((numbytes = send(acceptfd, &control, sizeof(char), MSG_NOSIGNAL)) < sizeof(char)) {
 748                                 perror("Error in sending PREFETCH RESPONSE to Coordinator\n");
 749                                 return 1;
 750                         }
 751                 }
 752
 753                 /* Add the buffer size into buffer as a parameter */
 754                 *((unsigned int *)buffer)=index;
 755                 /* Send the entire buffer with its size and oids found and not found */
 756                 if(send((int)acceptfd, &buffer, index, MSG_NOSIGNAL) < sizeof(index -1)) {
 757                         perror("Error sending oids found\n");
 758                         return 1;
 759                 }
 760         }
 761         return 0;
 762 }
 763
 764 void processReqNotify(unsigned int numoid, unsigned int *oidarry, unsigned short *versionarry, unsigned int mid, unsigned int threadid) {
 765         objheader_t *header;
 766         unsigned int oid;
 767         unsigned short newversion;
 768         char msg[1+  2 * sizeof(unsigned int) + sizeof(unsigned short)];
 769         int sd;
 770         struct sockaddr_in remoteAddr;
 771         int bytesSent;
 772         int status, size, retry = 0;
 773
 774         int i = 0;
 775         while(i < numoid) {
 776                 oid = *(oidarry + i);
 777                 if((header = (objheader_t *) mhashSearch(oid)) == NULL) {
 778                         printf("processReqNotify(): Object is not found in mlookup %s, %d\n", __FILE__, __LINE__);
 779                         return;
 780                 } else {
 781                         /* Check to see if versions are same */
 782 checkversion:
 783                         if ((STATUS(header) & LOCK) != LOCK) {
 784                                 STATUS(header) |= LOCK;
 785                                 if(header->version == *(versionarry + i)) {
 786                                         //Add to the notify list
 787                                         insNode(header->notifylist, threadid, mid);
 788                                 } else {
 789                                         if ((sd = socket(AF_INET, SOCK_STREAM, 0)) < 0){
 790                                                 perror("processReqNotify():socket()");
 791                                                 return;
 792                                         }
 793                                         bzero(&remoteAddr, sizeof(remoteAddr));
 794                                         remoteAddr.sin_family = AF_INET;
 795                                         remoteAddr.sin_port = htons(LISTEN_PORT);
 796                                         remoteAddr.sin_addr.s_addr = htonl(mid);
 797
 798                                         if (connect(sd, (struct sockaddr *)&remoteAddr, sizeof(remoteAddr)) < 0){
 799                                                 printf("processReqNotify():error %d connecting to %s:%d\n", errno,
 800                                                                 inet_ntoa(remoteAddr.sin_addr), LISTEN_PORT);
 801                                                 status = -1;
 802                                         } else {
 803                                                 //Send Update notification
 804                                                 msg[0] = THREAD_NOTIFY_RESPONSE;
 805                                                 msg[1] = oid;
 806                                                 size = sizeof(unsigned int);
 807                                                 *((unsigned short *)(&msg[1]+size)) = newversion;
 808                                                 size += sizeof(unsigned short);
 809                                                 *((unsigned int *)(&msg[1]+size)) = threadid;
 810                                                 bytesSent = send(sd, msg, 1+ 2*sizeof(unsigned int) + sizeof(unsigned short), 0);
 811                                                 if (bytesSent < 0){
 812                                                         perror("processReqNotify():send()");
 813                                                         status = -1;
 814                                                 } else if (bytesSent != 1 + sizeof(unsigned short) + 2*sizeof(unsigned int)){
 815                                                         printf("processReqNotify(): error, sent %d bytes\n", bytesSent);
 816                                                         status = -1;
 817                                                 } else {
 818                                                         status = 0;
 819                                                 }
 820
 821                                         }
 822                                         close(sd);
 823                                 }
 824                                 STATUS(header) &= ~(LOCK);
 825                         } else {
 826                                 randomdelay();
 827                                 printf("processReqNotify() Object is still locked\n");
 828                                 goto checkversion;
 829                         }
 830                 }
 831         }
 832         free(oidarry);
 833         free(versionarry);
 834 }
 835