granicus.if.org Git - imagemagick/blob - MagickCore/distribute-cache.c

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %    DDDD    IIIII   SSSSS  TTTTT  RRRR   IIIII  BBBB   U   U  TTTTT  EEEEE   %
   6 %    D   D     I     SS       T    R   R    I    B   B  U   U    T    E       %
   7 %    D   D     I      SSS     T    RRRR     I    BBBB   U   U    T    EEE     %
   8 %    D   D     I        SS    T    R R      I    B   B  U   U    T    E       %
   9 %    DDDDA   IIIII   SSSSS    T    R  R   IIIII  BBBB    UUU     T    EEEEE   %
  10 %                                                                             %
  11 %                      CCCC   AAA    CCCC  H   H  EEEEE                       %
  12 %                     C      A   A  C      H   H  E                           %
  13 %                     C      AAAAA  C      HHHHH  EEE                         %
  14 %                     C      A   A  C      H   H  E                           %
  15 %                      CCCC  A   A   CCCC  H   H  EEEEE                       %
  16 %                                                                             %
  17 %                                                                             %
  18 %                 MagickCore Distributed Pixel Cache Methods                  %
  19 %                                                                             %
  20 %                              Software Design                                %
  21 %                                John Cristy                                  %
  22 %                                January 2013                                 %
  23 %                                                                             %
  24 %                                                                             %
  25 %  Copyright 1999-2013 ImageMagick Studio LLC, a non-profit organization      %
  26 %  dedicated to making software imaging solutions freely available.           %
  27 %                                                                             %
  28 %  You may not use this file except in compliance with the License.  You may  %
  29 %  obtain a copy of the License at                                            %
  30 %                                                                             %
  31 %    http://www.imagemagick.org/script/license.php                            %
  32 %                                                                             %
  33 %  Unless required by applicable law or agreed to in writing, software        %
  34 %  distributed under the License is distributed on an "AS IS" BASIS,          %
  35 %  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   %
  36 %  See the License for the specific language governing permissions and        %
  37 %  limitations under the License.                                             %
  38 %                                                                             %
  39 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  40 %
  41 % A distributed pixel cache is an extension of the traditional pixel cache
  42 % available on a single host.  The distributed pixel cache may span multiple
  43 % servers so that it can grow in size and transactional capacity to support
  44 % very large images.  Start up the pixel cache server on one or more machines.
  45 % When you read or operate on an image and the local pixel cache resources are
  46 % exhausted, ImageMagick contacts one or more of these remote pixel servers to
  47 % store or retrieve pixels.
  48 %
  49 */
  50 \f
  51 /*
  52   Include declarations.
  53 */
  54 #include "MagickCore/studio.h"
  55 #include "MagickCore/cache.h"
  56 #include "MagickCore/cache-private.h"
  57 #include "MagickCore/distribute-cache.h"
  58 #include "MagickCore/distribute-cache-private.h"
  59 #include "MagickCore/exception.h"
  60 #include "MagickCore/exception-private.h"
  61 #include "MagickCore/geometry.h"
  62 #include "MagickCore/image.h"
  63 #include "MagickCore/list.h"
  64 #include "MagickCore/locale_.h"
  65 #include "MagickCore/memory_.h"
  66 #include "MagickCore/nt-base-private.h"
  67 #include "MagickCore/pixel.h"
  68 #include "MagickCore/policy.h"
  69 #include "MagickCore/random_.h"
  70 #include "MagickCore/registry.h"
  71 #include "MagickCore/splay-tree.h"
  72 #include "MagickCore/string_.h"
  73 #include "MagickCore/string-private.h"
  74 #include "MagickCore/version.h"
  75 #include "MagickCore/version-private.h"
  76 #if defined(MAGICKCORE_HAVE_SOCKET)
  77 #include <netinet/in.h>
  78 #include <netdb.h>
  79 #include <sys/socket.h>
  80 #include <arpa/inet.h>
  81 #else
  82 #undef send
  83 #undef recv
  84 #define send(file,buffer,length,flags)  0
  85 #define recv(file,buffer,length,flags)  0
  86 #endif
  87 \f
  88 /*
  89   Define declarations.
  90 */
  91 #define DPCHostname  "127.0.0.1"
  92 #define DPCPendingConnections  10
  93 #define DPCPort  6668
  94 #define DPCSessionKeyLength  8
  95 #ifndef MSG_NOSIGNAL
  96 #  define MSG_NOSIGNAL 0
  97 #endif
  98 \f
  99 /*
 100 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 101 %                                                                             %
 102 %                                                                             %
 103 %                                                                             %
 104 +   A c q u i r e D i s t r i b u t e C a c h e I n f o                       %
 105 %                                                                             %
 106 %                                                                             %
 107 %                                                                             %
 108 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 109 %
 110 %  AcquireDistributeCacheInfo() allocates the DistributeCacheInfo structure.
 111 %
 112 %  The format of the AcquireDistributeCacheInfo method is:
 113 %
 114 %      DistributeCacheInfo *AcquireDistributeCacheInfo(ExceptionInfo *exception)
 115 %
 116 %  A description of each parameter follows:
 117 %
 118 %    o exception: return any errors or warnings in this structure.
 119 %
 120 */
 121
 122 static inline MagickSizeType MagickMin(const MagickSizeType x,
 123   const MagickSizeType y)
 124 {
 125   if (x < y)
 126     return(x);
 127   return(y);
 128 }
 129
 130 static inline MagickOffsetType dpc_read(int file,const MagickSizeType length,
 131   unsigned char *restrict message)
 132 {
 133   register MagickOffsetType
 134     i;
 135
 136   ssize_t
 137     count;
 138
 139   count=0;
 140   for (i=0; i < (MagickOffsetType) length; i+=count)
 141   {
 142     count=recv(file,message+i,(size_t) MagickMin(length-i,(MagickSizeType)
 143       SSIZE_MAX),0);
 144     if (count <= 0)
 145       {
 146         count=0;
 147         if (errno != EINTR)
 148           break;
 149       }
 150   }
 151   return(i);
 152 }
 153
 154 static int ConnectPixelCacheServer(const char *hostname,const int port,
 155   size_t *session_key,ExceptionInfo *exception)
 156 {
 157 #if defined(MAGICKCORE_HAVE_SOCKET)
 158   char
 159     service[MaxTextExtent];
 160
 161   const char
 162     *shared_secret;
 163
 164   int
 165     client_socket,
 166     status;
 167
 168   ssize_t
 169     count;
 170
 171   struct addrinfo
 172     hint,
 173     *result;
 174
 175   unsigned char
 176     secret[MaxTextExtent];
 177
 178   /*
 179     Connect to distributed pixel cache and get session key.
 180   */
 181   *session_key=0;
 182   shared_secret=GetPolicyValue("shared-secret");
 183   if (shared_secret == (const char *) NULL)
 184     {
 185       (void) ThrowMagickException(exception,GetMagickModule(),CacheError,
 186         "DistributedPixelCache","'%s'","shared secret expected");
 187       return(-1);
 188     }
 189   (void) ResetMagickMemory(&hint,0,sizeof(hint));
 190   hint.ai_family=AF_INET;
 191   hint.ai_socktype=SOCK_STREAM;
 192   hint.ai_flags=AI_PASSIVE;
 193   (void) FormatLocaleString(service,MaxTextExtent,"%d",port);
 194   status=getaddrinfo(hostname,service,&hint,&result);
 195   if (status != 0)
 196     {
 197       (void) ThrowMagickException(exception,GetMagickModule(),CacheError,
 198         "DistributedPixelCache","'%s'",hostname);
 199       return(-1);
 200     }
 201   client_socket=socket(result->ai_family,result->ai_socktype,
 202     result->ai_protocol);
 203   if (client_socket == -1)
 204     {
 205       (void) ThrowMagickException(exception,GetMagickModule(),CacheError,
 206         "DistributedPixelCache","'%s'",hostname);
 207       return(-1);
 208     }
 209   status=connect(client_socket,result->ai_addr,result->ai_addrlen);
 210   if (status == -1)
 211     {
 212       (void) ThrowMagickException(exception,GetMagickModule(),CacheError,
 213         "DistributedPixelCache","'%s'",hostname);
 214       return(-1);
 215     }
 216   count=recv(client_socket,secret,MaxTextExtent,0);
 217   if (count != -1)
 218     {
 219       StringInfo
 220         *nonce;
 221
 222       nonce=AcquireStringInfo(count);
 223       (void) memcpy(GetStringInfoDatum(nonce),secret,(size_t) count);
 224       *session_key=GetMagickSignature(nonce);
 225       nonce=DestroyStringInfo(nonce);
 226     }
 227   if (*session_key == 0)
 228     {
 229       close(client_socket);
 230       client_socket=(-1);
 231     }
 232   return(client_socket);
 233 #else
 234   (void) ThrowMagickException(exception,GetMagickModule(),MissingDelegateError,
 235     "DelegateLibrarySupportNotBuiltIn","distributed pixel cache");
 236   return(MagickFalse);
 237 #endif
 238 }
 239
 240 static char *GetHostname(int *port,ExceptionInfo *exception)
 241 {
 242   char
 243     *host,
 244     *hosts,
 245     **hostlist;
 246
 247   int
 248     argc;
 249
 250   register ssize_t
 251     i;
 252
 253   static size_t
 254     id = 0;
 255
 256   /*
 257     Parse host list (e.g. 192.168.100.1:6668,192.168.100.2:6668).
 258   */
 259   hosts=(char *) GetImageRegistry(StringRegistryType,"cache:hosts",
 260     exception);
 261   if (hosts == (char *) NULL)
 262     {
 263       *port=DPCPort;
 264       return(AcquireString(DPCHostname));
 265     }
 266   (void) SubstituteString(&hosts,","," ");
 267   hostlist=StringToArgv(hosts,&argc);
 268   hosts=DestroyString(hosts);
 269   if (hostlist == (char **) NULL)
 270     {
 271       *port=DPCPort;
 272       return(AcquireString(DPCHostname));
 273     }
 274   hosts=AcquireString(hostlist[(id++ % (argc-1))+1]);
 275   for (i=0; i < (ssize_t) argc; i++)
 276     hostlist[i]=DestroyString(hostlist[i]);
 277   hostlist=(char **) RelinquishMagickMemory(hostlist);
 278   (void) SubstituteString(&hosts,":"," ");
 279   hostlist=StringToArgv(hosts,&argc);
 280   if (hostlist == (char **) NULL)
 281     {
 282       *port=DPCPort;
 283       return(AcquireString(DPCHostname));
 284     }
 285   host=AcquireString(hostlist[1]);
 286   if (hostlist[2] == (char *) NULL)
 287     *port=DPCPort;
 288   else
 289     *port=StringToLong(hostlist[2]);
 290   for (i=0; i < (ssize_t) argc; i++)
 291     hostlist[i]=DestroyString(hostlist[i]);
 292   hostlist=(char **) RelinquishMagickMemory(hostlist);
 293   return(host);
 294 }
 295
 296 MagickPrivate DistributeCacheInfo *AcquireDistributeCacheInfo(
 297   ExceptionInfo *exception)
 298 {
 299   char
 300     *hostname;
 301
 302   DistributeCacheInfo
 303     *server_info;
 304
 305   size_t
 306     session_key;
 307
 308   /*
 309     Connect to the distributed pixel cache server.
 310   */
 311   server_info=(DistributeCacheInfo *) AcquireMagickMemory(sizeof(*server_info));
 312   if (server_info == (DistributeCacheInfo *) NULL)
 313     ThrowFatalException(ResourceLimitFatalError,"MemoryAllocationFailed");
 314   (void) ResetMagickMemory(server_info,0,sizeof(*server_info));
 315   server_info->signature=MagickSignature;
 316   server_info->port=0;
 317   hostname=GetHostname(&server_info->port,exception);
 318   session_key=0;
 319   server_info->file=ConnectPixelCacheServer(hostname,server_info->port,
 320     &session_key,exception);
 321   server_info->session_key=session_key;
 322   (void) CopyMagickString(server_info->hostname,hostname,MaxTextExtent);
 323   hostname=DestroyString(hostname);
 324   if (server_info->file == -1)
 325     server_info=DestroyDistributeCacheInfo(server_info);
 326   return(server_info);
 327 }
 328 \f
 329 /*
 330 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 331 %                                                                             %
 332 %                                                                             %
 333 %                                                                             %
 334 +   D e s t r o y D i s t r i b u t e C a c h e I n f o                       %
 335 %                                                                             %
 336 %                                                                             %
 337 %                                                                             %
 338 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 339 %
 340 %  DestroyDistributeCacheInfo() deallocates memory associated with an
 341 %  DistributeCacheInfo structure.
 342 %
 343 %  The format of the DestroyDistributeCacheInfo method is:
 344 %
 345 %      DistributeCacheInfo *DestroyDistributeCacheInfo(
 346 %        DistributeCacheInfo *server_info)
 347 %
 348 %  A description of each parameter follows:
 349 %
 350 %    o server_info: the distributed cache info.
 351 %
 352 */
 353 MagickPrivate DistributeCacheInfo *DestroyDistributeCacheInfo(
 354   DistributeCacheInfo *server_info)
 355 {
 356   assert(server_info != (DistributeCacheInfo *) NULL);
 357   assert(server_info->signature == MagickSignature);
 358   if (server_info->file > 0)
 359     (void) close(server_info->file);
 360   server_info->signature=(~MagickSignature);
 361   server_info=(DistributeCacheInfo *) RelinquishMagickMemory(server_info);
 362   return(server_info);
 363 }
 364 \f
 365 /*
 366 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 367 %                                                                             %
 368 %                                                                             %
 369 %                                                                             %
 370 +   D i s t r i b u t e P i x e l C a c h e S e r v e r                       %
 371 %                                                                             %
 372 %                                                                             %
 373 %                                                                             %
 374 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 375 %
 376 %  DistributePixelCacheServer() waits on the specified port for commands to
 377 %  create, read, update, or destroy a pixel cache.
 378 %
 379 %  The format of the DistributePixelCacheServer() method is:
 380 %
 381 %      void DistributePixelCacheServer(const int port)
 382 %
 383 %  A description of each parameter follows:
 384 %
 385 %    o port: connect the distributed pixel cache at this port.
 386 %
 387 %    o exception: return any errors or warnings in this structure.
 388 %
 389 */
 390
 391 static MagickBooleanType DestroyDistributeCache(SplayTreeInfo *registry,
 392   int file,const size_t session_key)
 393 {
 394   /*
 395     Destroy distributed pixel cache.
 396   */
 397   return(DeleteNodeFromSplayTree(registry,(const void *) session_key));
 398 }
 399
 400 static inline MagickOffsetType dpc_send(int file,const MagickSizeType length,
 401   const unsigned char *restrict message)
 402 {
 403   MagickOffsetType
 404     count;
 405
 406   register MagickOffsetType
 407     i;
 408
 409   /*
 410     Ensure a complete message is sent.
 411   */
 412   count=0;
 413   for (i=0; i < (MagickOffsetType) length; i+=count)
 414   {
 415     count=(MagickOffsetType) send(file,message+i,(size_t) MagickMin(length-i,
 416       (MagickSizeType) SSIZE_MAX),MSG_NOSIGNAL);
 417     if (count <= 0)
 418       {
 419         count=0;
 420         if (errno != EINTR)
 421           break;
 422       }
 423   }
 424   return(i);
 425 }
 426
 427 static MagickBooleanType OpenDistributeCache(SplayTreeInfo *registry,
 428   int file,const size_t session_key,ExceptionInfo *exception)
 429 {
 430   Image
 431     *image;
 432
 433   MagickBooleanType
 434     status;
 435
 436   MagickOffsetType
 437     count;
 438
 439   MagickSizeType
 440     length;
 441
 442   register unsigned char
 443     *p;
 444
 445   unsigned char
 446     message[MaxTextExtent];
 447
 448   /*
 449     Open distributed pixel cache.
 450   */
 451   image=AcquireImage((ImageInfo *) NULL,exception);
 452   if (image == (Image *) NULL)
 453     return(MagickFalse);
 454   length=sizeof(image->storage_class)+sizeof(image->colorspace)+
 455     sizeof(image->alpha_trait)+sizeof(image->mask)+sizeof(image->columns)+
 456     sizeof(image->rows)+sizeof(image->number_channels)+MaxPixelChannels*
 457     sizeof(*image->channel_map)+sizeof(image->metacontent_extent);
 458   count=dpc_read(file,length,message);
 459   if (count != (MagickOffsetType) length)
 460     return(MagickFalse);
 461   /*
 462     Deserialize the image attributes.
 463   */
 464   p=message;
 465   (void) memcpy(&image->storage_class,p,sizeof(image->storage_class));
 466   p+=sizeof(image->storage_class);
 467   (void) memcpy(&image->colorspace,p,sizeof(image->colorspace));
 468   p+=sizeof(image->colorspace);
 469   (void) memcpy(&image->alpha_trait,p,sizeof(image->alpha_trait));
 470   p+=sizeof(image->alpha_trait);
 471   (void) memcpy(&image->mask,p,sizeof(image->mask));
 472   p+=sizeof(image->mask);
 473   (void) memcpy(&image->columns,p,sizeof(image->columns));
 474   p+=sizeof(image->columns);
 475   (void) memcpy(&image->rows,p,sizeof(image->rows));
 476   p+=sizeof(image->rows);
 477   (void) memcpy(&image->number_channels,p,sizeof(image->number_channels));
 478   p+=sizeof(image->number_channels);
 479   (void) memcpy(image->channel_map,p,MaxPixelChannels*
 480     sizeof(*image->channel_map));
 481   p+=MaxPixelChannels*sizeof(*image->channel_map);
 482   (void) memcpy(&image->metacontent_extent,p,sizeof(image->metacontent_extent));
 483   p+=sizeof(image->metacontent_extent);
 484   if (SyncImagePixelCache(image,exception) == MagickFalse)
 485     return(MagickFalse);
 486   status=AddValueToSplayTree(registry,(const void *) session_key,image);
 487   return(status);
 488 }
 489
 490 static MagickBooleanType ReadDistributeCacheMetacontent(SplayTreeInfo *registry,
 491   int file,const size_t session_key,ExceptionInfo *exception)
 492 {
 493   const unsigned char
 494     *metacontent;
 495
 496   Image
 497     *image;
 498
 499   MagickOffsetType
 500     count;
 501
 502   MagickSizeType
 503     length;
 504
 505   RectangleInfo
 506     region;
 507
 508   register const Quantum
 509     *p;
 510
 511   register unsigned char
 512     *q;
 513
 514   unsigned char
 515     message[MaxTextExtent];
 516
 517   /*
 518     Read distributed pixel cache metacontent.
 519   */
 520   image=(Image *) GetValueFromSplayTree(registry,(const void *) session_key);
 521   if (image == (Image *) NULL)
 522     return(MagickFalse);
 523   length=sizeof(region.width)+sizeof(region.height)+sizeof(region.x)+
 524     sizeof(region.y)+sizeof(length);
 525   count=dpc_read(file,length,message);
 526   if (count != (MagickOffsetType) length)
 527     return(MagickFalse);
 528   q=message;
 529   (void) memcpy(&region.width,q,sizeof(region.width));
 530   q+=sizeof(region.width);
 531   (void) memcpy(&region.height,q,sizeof(region.height));
 532   q+=sizeof(region.height);
 533   (void) memcpy(&region.x,q,sizeof(region.x));
 534   q+=sizeof(region.x);
 535   (void) memcpy(&region.y,q,sizeof(region.y));
 536   q+=sizeof(region.y);
 537   (void) memcpy(&length,q,sizeof(length));
 538   q+=sizeof(length);
 539   p=GetVirtualPixels(image,region.x,region.y,region.width,region.height,
 540     exception);
 541   if (p == (const Quantum *) NULL)
 542     return(MagickFalse);
 543   metacontent=(const unsigned char *) GetVirtualMetacontent(image);
 544   count=dpc_send(file,length,metacontent);
 545   if (count != (MagickOffsetType) length)
 546     return(MagickFalse);
 547   return(MagickTrue);
 548 }
 549
 550 static MagickBooleanType ReadDistributeCachePixels(SplayTreeInfo *registry,
 551   int file,const size_t session_key,ExceptionInfo *exception)
 552 {
 553   Image
 554     *image;
 555
 556   MagickOffsetType
 557     count;
 558
 559   MagickSizeType
 560     length;
 561
 562   RectangleInfo
 563     region;
 564
 565   register const Quantum
 566     *p;
 567
 568   register unsigned char
 569     *q;
 570
 571   unsigned char
 572     message[MaxTextExtent];
 573
 574   /*
 575     Read distributed pixel cache pixels.
 576   */
 577   image=(Image *) GetValueFromSplayTree(registry,(const void *) session_key);
 578   if (image == (Image *) NULL)
 579     return(MagickFalse);
 580   length=sizeof(region.width)+sizeof(region.height)+sizeof(region.x)+
 581     sizeof(region.y)+sizeof(length);
 582   count=dpc_read(file,length,message);
 583   if (count != (MagickOffsetType) length)
 584     return(MagickFalse);
 585   q=message;
 586   (void) memcpy(&region.width,q,sizeof(region.width));
 587   q+=sizeof(region.width);
 588   (void) memcpy(&region.height,q,sizeof(region.height));
 589   q+=sizeof(region.height);
 590   (void) memcpy(&region.x,q,sizeof(region.x));
 591   q+=sizeof(region.x);
 592   (void) memcpy(&region.y,q,sizeof(region.y));
 593   q+=sizeof(region.y);
 594   (void) memcpy(&length,q,sizeof(length));
 595   q+=sizeof(length);
 596   p=GetVirtualPixels(image,region.x,region.y,region.width,region.height,
 597     exception);
 598   if (p == (const Quantum *) NULL)
 599     return(MagickFalse);
 600   count=dpc_send(file,length,(unsigned char *) p);
 601   if (count != (MagickOffsetType) length)
 602     return(MagickFalse);
 603   return(MagickTrue);
 604 }
 605
 606 static void *RelinquishImageRegistry(void *image)
 607 {
 608   return((void *) DestroyImageList((Image *) image));
 609 }
 610
 611 static MagickBooleanType WriteDistributeCacheMetacontent(
 612   SplayTreeInfo *registry,int file,const size_t session_key,
 613   ExceptionInfo *exception)
 614 {
 615   Image
 616     *image;
 617
 618   MagickOffsetType
 619     count;
 620
 621   MagickSizeType
 622     length;
 623
 624   RectangleInfo
 625     region;
 626
 627   register Quantum
 628     *q;
 629
 630   register unsigned char
 631     *p;
 632
 633   unsigned char
 634     message[MaxTextExtent],
 635     *metacontent;
 636
 637   /*
 638     Write distributed pixel cache metacontent.
 639   */
 640   image=(Image *) GetValueFromSplayTree(registry,(const void *) session_key);
 641   if (image == (Image *) NULL)
 642     return(MagickFalse);
 643   length=sizeof(region.width)+sizeof(region.height)+sizeof(region.x)+
 644     sizeof(region.y)+sizeof(length);
 645   count=dpc_read(file,length,message);
 646   if (count != (MagickOffsetType) length)
 647     return(MagickFalse);
 648   p=message;
 649   (void) memcpy(&region.width,p,sizeof(region.width));
 650   p+=sizeof(region.width);
 651   (void) memcpy(&region.height,p,sizeof(region.height));
 652   p+=sizeof(region.height);
 653   (void) memcpy(&region.x,p,sizeof(region.x));
 654   p+=sizeof(region.x);
 655   (void) memcpy(&region.y,p,sizeof(region.y));
 656   p+=sizeof(region.y);
 657   (void) memcpy(&length,p,sizeof(length));
 658   p+=sizeof(length);
 659   q=GetAuthenticPixels(image,region.x,region.y,region.width,region.height,
 660     exception);
 661   if (q == (Quantum *) NULL)
 662     return(MagickFalse);
 663   metacontent=(unsigned char *) GetAuthenticMetacontent(image);
 664   count=dpc_read(file,length,metacontent);
 665   if (count != (MagickOffsetType) length)
 666     return(MagickFalse);
 667   return(SyncAuthenticPixels(image,exception));
 668 }
 669
 670 static MagickBooleanType WriteDistributeCachePixels(SplayTreeInfo *registry,
 671   int file,const size_t session_key,ExceptionInfo *exception)
 672 {
 673   Image
 674     *image;
 675
 676   MagickOffsetType
 677     count;
 678
 679   MagickSizeType
 680     length;
 681
 682   RectangleInfo
 683     region;
 684
 685   register Quantum
 686     *q;
 687
 688   register unsigned char
 689     *p;
 690
 691   unsigned char
 692     message[MaxTextExtent];
 693
 694   /*
 695     Write distributed pixel cache pixels.
 696   */
 697   image=(Image *) GetValueFromSplayTree(registry,(const void *) session_key);
 698   if (image == (Image *) NULL)
 699     return(MagickFalse);
 700   length=sizeof(region.width)+sizeof(region.height)+sizeof(region.x)+
 701     sizeof(region.y)+sizeof(length);
 702   count=dpc_read(file,length,message);
 703   if (count != (MagickOffsetType) length)
 704     return(MagickFalse);
 705   p=message;
 706   (void) memcpy(&region.width,p,sizeof(region.width));
 707   p+=sizeof(region.width);
 708   (void) memcpy(&region.height,p,sizeof(region.height));
 709   p+=sizeof(region.height);
 710   (void) memcpy(&region.x,p,sizeof(region.x));
 711   p+=sizeof(region.x);
 712   (void) memcpy(&region.y,p,sizeof(region.y));
 713   p+=sizeof(region.y);
 714   (void) memcpy(&length,p,sizeof(length));
 715   p+=sizeof(length);
 716   q=GetAuthenticPixels(image,region.x,region.y,region.width,region.height,
 717     exception);
 718   if (q == (Quantum *) NULL)
 719     return(MagickFalse);
 720   count=dpc_read(file,length,(unsigned char *) q);
 721   if (count != (MagickOffsetType) length)
 722     return(MagickFalse);
 723   return(SyncAuthenticPixels(image,exception));
 724 }
 725
 726 static void *DistributePixelCacheClient(void *socket)
 727 {
 728   const char
 729     *shared_secret;
 730
 731   ExceptionInfo
 732     *exception;
 733
 734   int
 735     client_socket;
 736
 737   MagickBooleanType
 738     status;
 739
 740   MagickOffsetType
 741     count;
 742
 743   register unsigned char
 744     *p;
 745
 746   RandomInfo
 747     *random_info;
 748
 749   size_t
 750     key,
 751     session_key;
 752
 753   SplayTreeInfo
 754     *registry;
 755
 756   StringInfo
 757     *secret;
 758
 759   unsigned char
 760     command,
 761     session[2*MaxTextExtent];
 762
 763   /*
 764     Distributed pixel cache client.
 765   */
 766   shared_secret=GetPolicyValue("shared-secret");
 767   if (shared_secret == (const char *) NULL)
 768     ThrowFatalException(CacheFatalError,"shared secret expected");
 769   p=session;
 770   (void) CopyMagickString((char *) p,shared_secret,MaxTextExtent);
 771   p+=strlen(shared_secret);
 772   random_info=AcquireRandomInfo();
 773   secret=GetRandomKey(random_info,DPCSessionKeyLength);
 774   (void) memcpy(p,GetStringInfoDatum(secret),DPCSessionKeyLength);
 775   session_key=GetMagickSignature(secret);
 776   random_info=DestroyRandomInfo(random_info);
 777   exception=AcquireExceptionInfo();
 778   registry=NewSplayTree((int (*)(const void *,const void *)) NULL,
 779     (void *(*)(void *)) NULL,RelinquishImageRegistry);
 780   client_socket=(*(int *) socket);
 781   count=dpc_send(client_socket,DPCSessionKeyLength,GetStringInfoDatum(secret));
 782   secret=DestroyStringInfo(secret);
 783   for ( ; ; )
 784   {
 785     count=dpc_read(client_socket,1,(unsigned char *) &command);
 786     if (count <= 0)
 787       break;
 788     count=dpc_read(client_socket,sizeof(key),(unsigned char *) &key);
 789     if ((count != (MagickOffsetType) sizeof(key)) || (key != session_key))
 790       break;
 791     status=MagickFalse;
 792     switch (command)
 793     {
 794       case 'o':
 795       {
 796         status=OpenDistributeCache(registry,client_socket,session_key,
 797           exception);
 798         count=dpc_send(client_socket,sizeof(status),(unsigned char *) &status);
 799         break;
 800       }
 801       case 'r':
 802       {
 803         status=ReadDistributeCachePixels(registry,client_socket,session_key,
 804           exception);
 805         break;
 806       }
 807       case 'R':
 808       {
 809         status=ReadDistributeCacheMetacontent(registry,client_socket,
 810           session_key,exception);
 811         break;
 812       }
 813       case 'w':
 814       {
 815         status=WriteDistributeCachePixels(registry,client_socket,session_key,
 816           exception);
 817         break;
 818       }
 819       case 'W':
 820       {
 821         status=WriteDistributeCacheMetacontent(registry,client_socket,
 822           session_key,exception);
 823         break;
 824       }
 825       case 'd':
 826       {
 827         status=DestroyDistributeCache(registry,client_socket,session_key);
 828         break;
 829       }
 830       default:
 831         break;
 832     }
 833     if (status == MagickFalse)
 834       break;
 835     if (command == 'd')
 836       break;
 837   }
 838   count=dpc_send(client_socket,sizeof(status),(unsigned char *) &status);
 839   (void) close(client_socket);
 840   exception=DestroyExceptionInfo(exception);
 841   registry=DestroySplayTree(registry);
 842   return((void *) NULL);
 843 }
 844
 845 MagickExport void DistributePixelCacheServer(const int port,
 846   ExceptionInfo *exception)
 847 {
 848 #if defined(MAGICKCORE_HAVE_SOCKET)
 849   char
 850     service[MaxTextExtent];
 851
 852   int
 853     server_socket,
 854     status;
 855
 856   pthread_attr_t
 857     attributes;
 858
 859   pthread_t
 860     threads;
 861
 862   register struct addrinfo
 863     *p;
 864
 865   struct addrinfo
 866     hint,
 867     *result;
 868
 869   struct sockaddr_in
 870     address;
 871
 872   /*
 873     Launch distributed pixel cache server.
 874   */
 875   (void) ResetMagickMemory(&hint,0,sizeof(hint));
 876   hint.ai_family=AF_INET;
 877   hint.ai_socktype=SOCK_STREAM;
 878   hint.ai_flags=AI_PASSIVE;
 879   (void) FormatLocaleString(service,MaxTextExtent,"%d",port);
 880   status=getaddrinfo((const char *) NULL,service,&hint,&result);
 881   if (status != 0)
 882     ThrowFatalException(CacheFatalError,"UnableToListen");
 883   server_socket=0;
 884   for (p=result; p != (struct addrinfo *) NULL; p=p->ai_next)
 885   {
 886     int
 887       one;
 888
 889     server_socket=socket(p->ai_family,p->ai_socktype,p->ai_protocol);
 890     if (server_socket == -1)
 891       continue;
 892     one=1;
 893     status=setsockopt(server_socket,SOL_SOCKET,SO_REUSEADDR,&one,(socklen_t)
 894       sizeof(one));
 895     if (status == -1)
 896       continue;
 897     status=bind(server_socket,p->ai_addr,p->ai_addrlen);
 898     if (status == -1)
 899       {
 900         (void) close(status);
 901         continue;
 902       }
 903     break;
 904   }
 905   if (p == (struct addrinfo *) NULL)
 906     ThrowFatalException(CacheFatalError,"UnableToBind");
 907   freeaddrinfo(result);
 908   status=listen(server_socket,DPCPendingConnections);
 909   if (status != 0)
 910     ThrowFatalException(CacheFatalError,"UnableToListen");
 911   pthread_attr_init(&attributes);
 912   for ( ; ; )
 913   {
 914     int
 915       client_socket;
 916
 917     socklen_t
 918       length;
 919
 920     length=(socklen_t) sizeof(address);
 921     client_socket=accept(server_socket,(struct sockaddr *) &address,&length);
 922     if (client_socket == -1)
 923       ThrowFatalException(CacheFatalError,"UnableToEstablishConnection");
 924     status=pthread_create(&threads,&attributes,DistributePixelCacheClient,
 925       (void *) &client_socket);
 926     if (status == -1)
 927       ThrowFatalException(CacheFatalError,"UnableToCreateClientThread");
 928   }
 929   (void) close(server_socket);
 930 #else
 931   ThrowFatalException(MissingDelegateError,"distributed pixel cache");
 932 #endif
 933 }
 934 \f
 935 /*
 936 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 937 %                                                                             %
 938 %                                                                             %
 939 %                                                                             %
 940 +   G e t D i s t r i b u t e C a c h e F i l e                               %
 941 %                                                                             %
 942 %                                                                             %
 943 %                                                                             %
 944 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 945 %
 946 %  GetDistributeCacheFile() returns the file associated with this
 947 %  DistributeCacheInfo structure.
 948 %
 949 %  The format of the GetDistributeCacheFile method is:
 950 %
 951 %      int GetDistributeCacheFile(const DistributeCacheInfo *server_info)
 952 %
 953 %  A description of each parameter follows:
 954 %
 955 %    o server_info: the distributed cache info.
 956 %
 957 */
 958 MagickPrivate int GetDistributeCacheFile(const DistributeCacheInfo *server_info)
 959 {
 960   assert(server_info != (DistributeCacheInfo *) NULL);
 961   assert(server_info->signature == MagickSignature);
 962   return(server_info->file);
 963 }
 964 \f
 965 /*
 966 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 967 %                                                                             %
 968 %                                                                             %
 969 %                                                                             %
 970 +   G e t D i s t r i b u t e C a c h e H o s t n a m e                       %
 971 %                                                                             %
 972 %                                                                             %
 973 %                                                                             %
 974 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 975 %
 976 %  GetDistributeCacheHostname() returns the hostname associated with this
 977 %  DistributeCacheInfo structure.
 978 %
 979 %  The format of the GetDistributeCacheHostname method is:
 980 %
 981 %      const char *GetDistributeCacheHostname(
 982 %        const DistributeCacheInfo *server_info)
 983 %
 984 %  A description of each parameter follows:
 985 %
 986 %    o server_info: the distributed cache info.
 987 %
 988 */
 989 MagickPrivate const char *GetDistributeCacheHostname(
 990   const DistributeCacheInfo *server_info)
 991 {
 992   assert(server_info != (DistributeCacheInfo *) NULL);
 993   assert(server_info->signature == MagickSignature);
 994   return(server_info->hostname);
 995 }
 996 \f
 997 /*
 998 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 999 %                                                                             %
1000 %                                                                             %
1001 %                                                                             %
1002 +   G e t D i s t r i b u t e C a c h e P o r t                               %
1003 %                                                                             %
1004 %                                                                             %
1005 %                                                                             %
1006 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1007 %
1008 %  GetDistributeCachePort() returns the port associated with this
1009 %  DistributeCacheInfo structure.
1010 %
1011 %  The format of the GetDistributeCachePort method is:
1012 %
1013 %      int GetDistributeCachePort(const DistributeCacheInfo *server_info)
1014 %
1015 %  A description of each parameter follows:
1016 %
1017 %    o server_info: the distributed cache info.
1018 %
1019 */
1020 MagickPrivate int GetDistributeCachePort(const DistributeCacheInfo *server_info)
1021 {
1022   assert(server_info != (DistributeCacheInfo *) NULL);
1023   assert(server_info->signature == MagickSignature);
1024   return(server_info->port);
1025 }
1026 \f
1027 /*
1028 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1029 %                                                                             %
1030 %                                                                             %
1031 %                                                                             %
1032 +   O p e n D i s t r i b u t e P i x e l C a c h e                           %
1033 %                                                                             %
1034 %                                                                             %
1035 %                                                                             %
1036 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1037 %
1038 %  OpenDistributePixelCache() opens a pixel cache on a remote server.
1039 %
1040 %  The format of the OpenDistributePixelCache method is:
1041 %
1042 %      MagickBooleanType *OpenDistributePixelCache(
1043 %        DistributeCacheInfo *server_info,Image *image)
1044 %
1045 %  A description of each parameter follows:
1046 %
1047 %    o server_info: the distributed cache info.
1048 %
1049 %    o image: the image.
1050 %
1051 */
1052 MagickPrivate MagickBooleanType OpenDistributePixelCache(
1053   DistributeCacheInfo *server_info,Image *image)
1054 {
1055   MagickBooleanType
1056     status;
1057
1058   MagickOffsetType
1059     count;
1060
1061   register unsigned char
1062     *p;
1063
1064   unsigned char
1065     message[MaxTextExtent];
1066
1067   /*
1068     Open distributed pixel cache.
1069   */
1070   assert(server_info != (DistributeCacheInfo *) NULL);
1071   assert(server_info->signature == MagickSignature);
1072   assert(image != (Image *) NULL);
1073   assert(image->signature == MagickSignature);
1074   p=message;
1075   *p++='o';  /* open */
1076   /*
1077     Serialize image attributes (see ValidatePixelCacheMorphology()).
1078   */
1079   (void) memcpy(p,&server_info->session_key,sizeof(server_info->session_key));
1080   p+=sizeof(server_info->session_key);
1081   (void) memcpy(p,&image->storage_class,sizeof(image->storage_class));
1082   p+=sizeof(image->storage_class);
1083   (void) memcpy(p,&image->colorspace,sizeof(image->colorspace));
1084   p+=sizeof(image->colorspace);
1085   (void) memcpy(p,&image->alpha_trait,sizeof(image->alpha_trait));
1086   p+=sizeof(image->alpha_trait);
1087   (void) memcpy(p,&image->mask,sizeof(image->mask));
1088   p+=sizeof(image->mask);
1089   (void) memcpy(p,&image->columns,sizeof(image->columns));
1090   p+=sizeof(image->columns);
1091   (void) memcpy(p,&image->rows,sizeof(image->rows));
1092   p+=sizeof(image->rows);
1093   (void) memcpy(p,&image->number_channels,sizeof(image->number_channels));
1094   p+=sizeof(image->number_channels);
1095   (void) memcpy(p,image->channel_map,MaxPixelChannels*
1096     sizeof(*image->channel_map));
1097   p+=MaxPixelChannels*sizeof(*image->channel_map);
1098   (void) memcpy(p,&image->metacontent_extent,sizeof(image->metacontent_extent));
1099   p+=sizeof(image->metacontent_extent);
1100   count=dpc_send(server_info->file,p-message,message);
1101   if (count != (MagickOffsetType) (p-message))
1102     return(MagickFalse);
1103   status=MagickFalse;
1104   count=dpc_read(server_info->file,sizeof(status),(unsigned char *) &status);
1105   if (count != (MagickOffsetType) sizeof(status))
1106     return(MagickFalse);
1107   return(status);
1108 }
1109 \f
1110 /*
1111 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1112 %                                                                             %
1113 %                                                                             %
1114 %                                                                             %
1115 +   R e a d D i s t r i b u t e P i x e l C a c h e M e t a c o n t e n t     %
1116 %                                                                             %
1117 %                                                                             %
1118 %                                                                             %
1119 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1120 %
1121 %  ReadDistributePixelCacheMetacontents() reads metacontent from the specified
1122 %  region of the distributed pixel cache.
1123 %
1124 %  The format of the ReadDistributePixelCacheMetacontents method is:
1125 %
1126 %      MagickOffsetType ReadDistributePixelCacheMetacontents(
1127 %        DistributeCacheInfo *server_info,const RectangleInfo *region,
1128 %        const MagickSizeType length,unsigned char *metacontent)
1129 %
1130 %  A description of each parameter follows:
1131 %
1132 %    o server_info: the distributed cache info.
1133 %
1134 %    o image: the image.
1135 %
1136 %    o region: read the metacontent from this region of the image.
1137 %
1138 %    o length: the length in bytes of the metacontent.
1139 %
1140 %    o metacontent: read these metacontent from the pixel cache.
1141 %
1142 */
1143 MagickPrivate MagickOffsetType ReadDistributePixelCacheMetacontent(
1144   DistributeCacheInfo *server_info,const RectangleInfo *region,
1145   const MagickSizeType length,unsigned char *metacontent)
1146 {
1147   MagickOffsetType
1148     count;
1149
1150   register unsigned char
1151     *p;
1152
1153   unsigned char
1154     message[MaxTextExtent];
1155
1156   /*
1157     Read distributed pixel cache metacontent.
1158   */
1159   assert(server_info != (DistributeCacheInfo *) NULL);
1160   assert(server_info->signature == MagickSignature);
1161   assert(region != (RectangleInfo *) NULL);
1162   assert(metacontent != (unsigned char *) NULL);
1163   if (length > (MagickSizeType) SSIZE_MAX)
1164     return(-1);
1165   p=message;
1166   *p++='R';
1167   (void) memcpy(p,&server_info->session_key,sizeof(server_info->session_key));
1168   p+=sizeof(server_info->session_key);
1169   (void) memcpy(p,&region->width,sizeof(region->width));
1170   p+=sizeof(region->width);
1171   (void) memcpy(p,&region->height,sizeof(region->height));
1172   p+=sizeof(region->height);
1173   (void) memcpy(p,&region->x,sizeof(region->x));
1174   p+=sizeof(region->x);
1175   (void) memcpy(p,&region->y,sizeof(region->y));
1176   p+=sizeof(region->y);
1177   (void) memcpy(p,&length,sizeof(length));
1178   p+=sizeof(length);
1179   count=dpc_send(server_info->file,p-message,message);
1180   if (count != (MagickOffsetType) (p-message))
1181     return(-1);
1182   return(dpc_read(server_info->file,length,metacontent));
1183 }
1184 \f
1185 /*
1186 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1187 %                                                                             %
1188 %                                                                             %
1189 %                                                                             %
1190 +   R e a d D i s t r i b u t e P i x e l C a c h e P i x e l s               %
1191 %                                                                             %
1192 %                                                                             %
1193 %                                                                             %
1194 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1195 %
1196 %  ReadDistributePixelCachePixels() reads pixels from the specified region of
1197 %  the distributed pixel cache.
1198 %
1199 %  The format of the ReadDistributePixelCachePixels method is:
1200 %
1201 %      MagickOffsetType ReadDistributePixelCachePixels(
1202 %        DistributeCacheInfo *server_info,const RectangleInfo *region,
1203 %        const MagickSizeType length,unsigned char *pixels)
1204 %
1205 %  A description of each parameter follows:
1206 %
1207 %    o server_info: the distributed cache info.
1208 %
1209 %    o image: the image.
1210 %
1211 %    o region: read the pixels from this region of the image.
1212 %
1213 %    o length: the length in bytes of the pixels.
1214 %
1215 %    o pixels: read these pixels from the pixel cache.
1216 %
1217 */
1218 MagickPrivate MagickOffsetType ReadDistributePixelCachePixels(
1219   DistributeCacheInfo *server_info,const RectangleInfo *region,
1220   const MagickSizeType length,unsigned char *pixels)
1221 {
1222   MagickOffsetType
1223     count;
1224
1225   register unsigned char
1226     *p;
1227
1228   unsigned char
1229     message[MaxTextExtent];
1230
1231   /*
1232     Read distributed pixel cache pixels.
1233   */
1234   assert(server_info != (DistributeCacheInfo *) NULL);
1235   assert(server_info->signature == MagickSignature);
1236   assert(region != (RectangleInfo *) NULL);
1237   assert(pixels != (unsigned char *) NULL);
1238   if (length > (MagickSizeType) SSIZE_MAX)
1239     return(-1);
1240   p=message;
1241   *p++='r';
1242   (void) memcpy(p,&server_info->session_key,sizeof(server_info->session_key));
1243   p+=sizeof(server_info->session_key);
1244   (void) memcpy(p,&region->width,sizeof(region->width));
1245   p+=sizeof(region->width);
1246   (void) memcpy(p,&region->height,sizeof(region->height));
1247   p+=sizeof(region->height);
1248   (void) memcpy(p,&region->x,sizeof(region->x));
1249   p+=sizeof(region->x);
1250   (void) memcpy(p,&region->y,sizeof(region->y));
1251   p+=sizeof(region->y);
1252   (void) memcpy(p,&length,sizeof(length));
1253   p+=sizeof(length);
1254   count=dpc_send(server_info->file,p-message,message);
1255   if (count != (MagickOffsetType) (p-message))
1256     return(-1);
1257   return(dpc_read(server_info->file,length,pixels));
1258 }
1259 \f
1260 /*
1261 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1262 %                                                                             %
1263 %                                                                             %
1264 %                                                                             %
1265 +   R e l i n q u i s h D i s t r i b u t e P i x e l C a c h e               %
1266 %                                                                             %
1267 %                                                                             %
1268 %                                                                             %
1269 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1270 %
1271 %  RelinquishDistributePixelCache() frees resources acquired with
1272 %  OpenDistributePixelCache().
1273 %
1274 %  The format of the RelinquishDistributePixelCache method is:
1275 %
1276 %      MagickBooleanType RelinquishDistributePixelCache(
1277 %        DistributeCacheInfo *server_info)
1278 %
1279 %  A description of each parameter follows:
1280 %
1281 %    o server_info: the distributed cache info.
1282 %
1283 */
1284 MagickPrivate MagickBooleanType RelinquishDistributePixelCache(
1285   DistributeCacheInfo *server_info)
1286 {
1287   MagickBooleanType
1288     status;
1289
1290   MagickOffsetType
1291     count;
1292
1293   register unsigned char
1294     *p;
1295
1296   unsigned char
1297     message[MaxTextExtent];
1298
1299   /*
1300     Delete distributed pixel cache.
1301   */
1302   assert(server_info != (DistributeCacheInfo *) NULL);
1303   assert(server_info->signature == MagickSignature);
1304   p=message;
1305   *p++='d';
1306   (void) memcpy(p,&server_info->session_key,sizeof(server_info->session_key));
1307   p+=sizeof(server_info->session_key);
1308   count=dpc_send(server_info->file,p-message,message);
1309   if (count != (MagickOffsetType) (p-message))
1310     return(MagickFalse);
1311   count=dpc_read(server_info->file,sizeof(status),(unsigned char *) &status);
1312   if (count != (MagickOffsetType) sizeof(status))
1313     return(MagickFalse);
1314   return(status);
1315 }
1316 \f
1317 /*
1318 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1319 %                                                                             %
1320 %                                                                             %
1321 %                                                                             %
1322 +   W r i t e D i s t r i b u t e P i x e l C a c h e M e t a c o n t e n t   %
1323 %                                                                             %
1324 %                                                                             %
1325 %                                                                             %
1326 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1327 %
1328 %  WriteDistributePixelCacheMetacontents() writes image metacontent to the
1329 %  specified region of the distributed pixel cache.
1330 %
1331 %  The format of the WriteDistributePixelCacheMetacontents method is:
1332 %
1333 %      MagickOffsetType WriteDistributePixelCacheMetacontents(
1334 %        DistributeCacheInfo *server_info,const RectangleInfo *region,
1335 %        const MagickSizeType length,const unsigned char *metacontent)
1336 %
1337 %  A description of each parameter follows:
1338 %
1339 %    o server_info: the distributed cache info.
1340 %
1341 %    o image: the image.
1342 %
1343 %    o region: write the metacontent to this region of the image.
1344 %
1345 %    o length: the length in bytes of the metacontent.
1346 %
1347 %    o metacontent: write these metacontent to the pixel cache.
1348 %
1349 */
1350 MagickPrivate MagickOffsetType WriteDistributePixelCacheMetacontent(
1351   DistributeCacheInfo *server_info,const RectangleInfo *region,
1352   const MagickSizeType length,const unsigned char *metacontent)
1353 {
1354   MagickOffsetType
1355     count;
1356
1357   register unsigned char
1358     *p;
1359
1360   unsigned char
1361     message[MaxTextExtent];
1362
1363   /*
1364     Write distributed pixel cache metacontent.
1365   */
1366   assert(server_info != (DistributeCacheInfo *) NULL);
1367   assert(server_info->signature == MagickSignature);
1368   assert(region != (RectangleInfo *) NULL);
1369   assert(metacontent != (unsigned char *) NULL);
1370   if (length > (MagickSizeType) SSIZE_MAX)
1371     return(-1);
1372   p=message;
1373   *p++='W';
1374   (void) memcpy(p,&server_info->session_key,sizeof(server_info->session_key));
1375   p+=sizeof(server_info->session_key);
1376   (void) memcpy(p,&region->width,sizeof(region->width));
1377   p+=sizeof(region->width);
1378   (void) memcpy(p,&region->height,sizeof(region->height));
1379   p+=sizeof(region->height);
1380   (void) memcpy(p,&region->x,sizeof(region->x));
1381   p+=sizeof(region->x);
1382   (void) memcpy(p,&region->y,sizeof(region->y));
1383   p+=sizeof(region->y);
1384   (void) memcpy(p,&length,sizeof(length));
1385   p+=sizeof(length);
1386   count=dpc_send(server_info->file,p-message,message);
1387   if (count != (MagickOffsetType) (p-message))
1388     return(-1);
1389   return(dpc_send(server_info->file,length,metacontent));
1390 }
1391 \f
1392 /*
1393 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1394 %                                                                             %
1395 %                                                                             %
1396 %                                                                             %
1397 +   W r i t e D i s t r i b u t e P i x e l C a c h e P i x e l s             %
1398 %                                                                             %
1399 %                                                                             %
1400 %                                                                             %
1401 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1402 %
1403 %  WriteDistributePixelCachePixels() writes image pixels to the specified
1404 %  region of the distributed pixel cache.
1405 %
1406 %  The format of the WriteDistributePixelCachePixels method is:
1407 %
1408 %      MagickBooleanType WriteDistributePixelCachePixels(
1409 %        DistributeCacheInfo *server_info,const RectangleInfo *region,
1410 %        const MagickSizeType length,const unsigned char *pixels)
1411 %
1412 %  A description of each parameter follows:
1413 %
1414 %    o server_info: the distributed cache info.
1415 %
1416 %    o image: the image.
1417 %
1418 %    o region: write the pixels to this region of the image.
1419 %
1420 %    o length: the length in bytes of the pixels.
1421 %
1422 %    o pixels: write these pixels to the pixel cache.
1423 %
1424 */
1425 MagickPrivate MagickOffsetType WriteDistributePixelCachePixels(
1426   DistributeCacheInfo *server_info,const RectangleInfo *region,
1427   const MagickSizeType length,const unsigned char *pixels)
1428 {
1429   MagickOffsetType
1430     count;
1431
1432   register unsigned char
1433     *p;
1434
1435   unsigned char
1436     message[MaxTextExtent];
1437
1438   /*
1439     Write distributed pixel cache pixels.
1440   */
1441   assert(server_info != (DistributeCacheInfo *) NULL);
1442   assert(server_info->signature == MagickSignature);
1443   assert(region != (RectangleInfo *) NULL);
1444   assert(pixels != (const unsigned char *) NULL);
1445   if (length > (MagickSizeType) SSIZE_MAX)
1446     return(-1);
1447   p=message;
1448   *p++='w';
1449   (void) memcpy(p,&server_info->session_key,sizeof(server_info->session_key));
1450   p+=sizeof(server_info->session_key);
1451   (void) memcpy(p,&region->width,sizeof(region->width));
1452   p+=sizeof(region->width);
1453   (void) memcpy(p,&region->height,sizeof(region->height));
1454   p+=sizeof(region->height);
1455   (void) memcpy(p,&region->x,sizeof(region->x));
1456   p+=sizeof(region->x);
1457   (void) memcpy(p,&region->y,sizeof(region->y));
1458   p+=sizeof(region->y);
1459   (void) memcpy(p,&length,sizeof(length));
1460   p+=sizeof(length);
1461   count=dpc_send(server_info->file,p-message,message);
1462   if (count != (MagickOffsetType) (p-message))
1463     return(-1);
1464   return(dpc_send(server_info->file,length,pixels));
1465 }