methods/rred.cc

   1 // Includes                                                                     /*{{{*/
   2 #include <apt-pkg/fileutl.h>
   3 #include <apt-pkg/mmap.h>
   4 #include <apt-pkg/error.h>
   5 #include <apt-pkg/acquire-method.h>
   6 #include <apt-pkg/strutl.h>
   7 #include <apt-pkg/hashes.h>
   8
   9 #include <sys/stat.h>
  10 #include <sys/uio.h>
  11 #include <unistd.h>
  12 #include <utime.h>
  13 #include <stdio.h>
  14 #include <errno.h>
  15 #include <zlib.h>
  16 #include <apti18n.h>
  17                                                                                 /*}}}*/
  18 /** \brief RredMethod - ed-style incremential patch method                      {{{
  19  *
  20  *  This method implements a patch functionality similar to "patch --ed" that is
  21  *  used by the "tiffany" incremental packages download stuff. It differs from
  22  *  "ed" insofar that it is way more restricted (and therefore secure).
  23  *  The currently supported ed commands are "<em>c</em>hange", "<em>a</em>dd" and
  24  *  "<em>d</em>elete" (diff doesn't output any other).
  25  *  Additionally the records must be reverse sorted by line number and
  26  *  may not overlap (diff *seems* to produce this kind of output).
  27  * */
  28 class RredMethod : public pkgAcqMethod {
  29         bool Debug;
  30         // the size of this doesn't really matter (except for performance)
  31         const static int BUF_SIZE = 1024;
  32         // the supported ed commands
  33         enum Mode {MODE_CHANGED='c', MODE_DELETED='d', MODE_ADDED='a'};
  34         // return values
  35         enum State {ED_OK, ED_ORDERING, ED_PARSER, ED_FAILURE, MMAP_FAILED};
  36
  37         State applyFile(gzFile &ed_cmds, FILE *in_file, FILE *out_file,
  38                      unsigned long &line, char *buffer, Hashes *hash) const;
  39         void ignoreLineInFile(FILE *fin, char *buffer) const;
  40         void ignoreLineInFile(gzFile &fin, char *buffer) const;
  41         void copyLinesFromFileToFile(FILE *fin, FILE *fout, unsigned int lines,
  42                                     Hashes *hash, char *buffer) const;
  43         void copyLinesFromFileToFile(gzFile &fin, FILE *fout, unsigned int lines,
  44                                     Hashes *hash, char *buffer) const;
  45
  46         State patchFile(FileFd &Patch, FileFd &From, FileFd &out_file, Hashes *hash) const;
  47         State patchMMap(FileFd &Patch, FileFd &From, FileFd &out_file, Hashes *hash) const;
  48
  49 protected:
  50         // the methods main method
  51         virtual bool Fetch(FetchItem *Itm);
  52
  53 public:
  54         RredMethod() : pkgAcqMethod("1.1",SingleInstance | SendConfig) {};
  55 };
  56                                                                                 /*}}}*/
  57 /** \brief applyFile - in reverse order with a tail recursion                   {{{
  58  *
  59  *  As it is expected that the commands are in reversed order in the patch file
  60  *  we check in the first half if the command is valid, but doesn't execute it
  61  *  and move a step deeper. After reaching the end of the file we apply the
  62  *  patches in the correct order: last found command first.
  63  *
  64  *  \param ed_cmds patch file to apply
  65  *  \param in_file base file we want to patch
  66  *  \param out_file file to write the patched result to
  67  *  \param line of command operation
  68  *  \param buffer internal used read/write buffer
  69  *  \param hash the created file for correctness
  70  *  \return the success State of the ed command executor
  71  */
  72 RredMethod::State RredMethod::applyFile(gzFile &ed_cmds, FILE *in_file, FILE *out_file,
  73                         unsigned long &line, char *buffer, Hashes *hash) const {
  74         // get the current command and parse it
  75         if (gzgets(ed_cmds, buffer, BUF_SIZE) == NULL) {
  76                 if (Debug == true)
  77                         std::clog << "rred: encounter end of file - we can start patching now." << std::endl;
  78                 line = 0;
  79                 return ED_OK;
  80         }
  81
  82         // parse in the effected linenumbers
  83         char* idx;
  84         errno=0;
  85         unsigned long const startline = strtol(buffer, &idx, 10);
  86         if (errno == ERANGE || errno == EINVAL) {
  87                 _error->Errno("rred", "startline is an invalid number");
  88                 return ED_PARSER;
  89         }
  90         if (startline > line) {
  91                 _error->Error("rred: The start line (%lu) of the next command is higher than the last line (%lu). This is not allowed.", startline, line);
  92                 return ED_ORDERING;
  93         }
  94         unsigned long stopline;
  95         if (*idx == ',') {
  96                 idx++;
  97                 errno=0;
  98                 stopline = strtol(idx, &idx, 10);
  99                 if (errno == ERANGE || errno == EINVAL) {
 100                         _error->Errno("rred", "stopline is an invalid number");
 101                         return ED_PARSER;
 102                 }
 103         }
 104         else {
 105                 stopline = startline;
 106         }
 107         line = startline;
 108
 109         // which command to execute on this line(s)?
 110         switch (*idx) {
 111                 case MODE_CHANGED:
 112                         if (Debug == true)
 113                                 std::clog << "Change from line " << startline << " to " << stopline << std::endl;
 114                         break;
 115                 case MODE_ADDED:
 116                         if (Debug == true)
 117                                 std::clog << "Insert after line " << startline << std::endl;
 118                         break;
 119                 case MODE_DELETED:
 120                         if (Debug == true)
 121                                 std::clog << "Delete from line " << startline << " to " << stopline << std::endl;
 122                         break;
 123                 default:
 124                         _error->Error("rred: Unknown ed command '%c'. Abort.", *idx);
 125                         return ED_PARSER;
 126         }
 127         unsigned char mode = *idx;
 128
 129         // save the current position
 130         unsigned const long pos = gztell(ed_cmds);
 131
 132         // if this is add or change then go to the next full stop
 133         unsigned int data_length = 0;
 134         if (mode == MODE_CHANGED || mode == MODE_ADDED) {
 135                 do {
 136                         ignoreLineInFile(ed_cmds, buffer);
 137                         data_length++;
 138                 }
 139                 while (strncmp(buffer, ".", 1) != 0);
 140                 data_length--; // the dot should not be copied
 141         }
 142
 143         // do the recursive call - the last command is the one we need to execute at first
 144         const State child = applyFile(ed_cmds, in_file, out_file, line, buffer, hash);
 145         if (child != ED_OK) {
 146                 return child;
 147         }
 148
 149         // change and delete are working on "line" - add is done after "line"
 150         if (mode != MODE_ADDED)
 151                 line++;
 152
 153         // first wind to the current position and copy over all unchanged lines
 154         if (line < startline) {
 155                 copyLinesFromFileToFile(in_file, out_file, (startline - line), hash, buffer);
 156                 line = startline;
 157         }
 158
 159         if (mode != MODE_ADDED)
 160                 line--;
 161
 162         // include data from ed script
 163         if (mode == MODE_CHANGED || mode == MODE_ADDED) {
 164                 gzseek(ed_cmds, pos, SEEK_SET);
 165                 copyLinesFromFileToFile(ed_cmds, out_file, data_length, hash, buffer);
 166         }
 167
 168         // ignore the corresponding number of lines from input
 169         if (mode == MODE_CHANGED || mode == MODE_DELETED) {
 170                 while (line < stopline) {
 171                         ignoreLineInFile(in_file, buffer);
 172                         line++;
 173                 }
 174         }
 175         return ED_OK;
 176 }
 177                                                                                 /*}}}*/
 178 void RredMethod::copyLinesFromFileToFile(FILE *fin, FILE *fout, unsigned int lines,/*{{{*/
 179                                         Hashes *hash, char *buffer) const {
 180         while (0 < lines--) {
 181                 do {
 182                         fgets(buffer, BUF_SIZE, fin);
 183                         size_t const written = fwrite(buffer, 1, strlen(buffer), fout);
 184                         hash->Add((unsigned char*)buffer, written);
 185                 } while (strlen(buffer) == (BUF_SIZE - 1) &&
 186                        buffer[BUF_SIZE - 2] != '\n');
 187         }
 188 }
 189                                                                                 /*}}}*/
 190 void RredMethod::copyLinesFromFileToFile(gzFile &fin, FILE *fout, unsigned int lines,/*{{{*/
 191                                         Hashes *hash, char *buffer) const {
 192         while (0 < lines--) {
 193                 do {
 194                         gzgets(fin, buffer, BUF_SIZE);
 195                         size_t const written = fwrite(buffer, 1, strlen(buffer), fout);
 196                         hash->Add((unsigned char*)buffer, written);
 197                 } while (strlen(buffer) == (BUF_SIZE - 1) &&
 198                        buffer[BUF_SIZE - 2] != '\n');
 199         }
 200 }
 201                                                                                 /*}}}*/
 202 void RredMethod::ignoreLineInFile(FILE *fin, char *buffer) const {              /*{{{*/
 203         fgets(buffer, BUF_SIZE, fin);
 204         while (strlen(buffer) == (BUF_SIZE - 1) &&
 205                buffer[BUF_SIZE - 2] != '\n') {
 206                 fgets(buffer, BUF_SIZE, fin);
 207                 buffer[0] = ' ';
 208         }
 209 }
 210                                                                                 /*}}}*/
 211 void RredMethod::ignoreLineInFile(gzFile &fin, char *buffer) const {            /*{{{*/
 212         gzgets(fin, buffer, BUF_SIZE);
 213         while (strlen(buffer) == (BUF_SIZE - 1) &&
 214                buffer[BUF_SIZE - 2] != '\n') {
 215                 gzgets(fin, buffer, BUF_SIZE);
 216                 buffer[0] = ' ';
 217         }
 218 }
 219                                                                                 /*}}}*/
 220 RredMethod::State RredMethod::patchFile(FileFd &Patch, FileFd &From,            /*{{{*/
 221                                         FileFd &out_file, Hashes *hash) const {
 222    char buffer[BUF_SIZE];
 223    FILE* fFrom = fdopen(From.Fd(), "r");
 224    gzFile fPatch = Patch.gzFd();
 225    FILE* fTo = fdopen(out_file.Fd(), "w");
 226
 227    /* we do a tail recursion to read the commands in the right order */
 228    unsigned long line = -1; // assign highest possible value
 229    State const result = applyFile(fPatch, fFrom, fTo, line, buffer, hash);
 230
 231    /* read the rest from infile */
 232    if (result == ED_OK) {
 233       while (fgets(buffer, BUF_SIZE, fFrom) != NULL) {
 234          size_t const written = fwrite(buffer, 1, strlen(buffer), fTo);
 235          hash->Add((unsigned char*)buffer, written);
 236       }
 237       fflush(fTo);
 238    }
 239    return result;
 240 }
 241                                                                                 /*}}}*/
 242 struct EdCommand {                                                              /*{{{*/
 243   size_t data_start;
 244   size_t data_end;
 245   size_t data_lines;
 246   size_t first_line;
 247   size_t last_line;
 248   char type;
 249 };
 250 #define IOV_COUNT 1024 /* Don't really want IOV_MAX since it can be arbitrarily large */
 251                                                                                 /*}}}*/
 252 RredMethod::State RredMethod::patchMMap(FileFd &Patch, FileFd &From,            /*{{{*/
 253                                         FileFd &out_file, Hashes *hash) const {
 254 #ifdef _POSIX_MAPPED_FILES
 255         MMap ed_cmds(MMap::ReadOnly);
 256         if (Patch.gzFd() != NULL) {
 257                 unsigned long mapSize = Patch.Size();
 258                 DynamicMMap* dyn = new DynamicMMap(0, mapSize, 0);
 259                 if (dyn->validData() == false) {
 260                         delete dyn;
 261                         return MMAP_FAILED;
 262                 }
 263                 dyn->AddSize(mapSize);
 264                 gzread(Patch.gzFd(), dyn->Data(), mapSize);
 265                 ed_cmds = *dyn;
 266         } else
 267                 ed_cmds = MMap(Patch, MMap::ReadOnly);
 268
 269         MMap in_file(From, MMap::ReadOnly);
 270
 271         if (ed_cmds.Size() == 0 || in_file.Size() == 0)
 272                 return MMAP_FAILED;
 273
 274         EdCommand* commands = 0;
 275         size_t command_count = 0;
 276         size_t command_alloc = 0;
 277
 278         const char* begin = (char*) ed_cmds.Data();
 279         const char* end = begin;
 280         const char* ed_end = (char*) ed_cmds.Data() + ed_cmds.Size();
 281
 282         const char* input = (char*) in_file.Data();
 283         const char* input_end = (char*) in_file.Data() + in_file.Size();
 284
 285         size_t i;
 286
 287         /* 1. Parse entire script.  It is executed in reverse order, so we cather it
 288          *    in the `commands' buffer first
 289          */
 290
 291         for(;;) {
 292                 EdCommand cmd;
 293                 cmd.data_start = 0;
 294                 cmd.data_end = 0;
 295
 296                 while(begin != ed_end && *begin == '\n')
 297                         ++begin;
 298                 while(end != ed_end && *end != '\n')
 299                         ++end;
 300                 if(end == ed_end && begin == end)
 301                         break;
 302
 303                 /* Determine command range */
 304                 const char* tmp = begin;
 305
 306                 for(;;) {
 307                         /* atoll is safe despite lacking NUL-termination; we know there's an
 308                          * alphabetic character at end[-1]
 309                          */
 310                         if(tmp == end) {
 311                                 cmd.first_line = atol(begin);
 312                                 cmd.last_line = cmd.first_line;
 313                                 break;
 314                         }
 315                         if(*tmp == ',') {
 316                                 cmd.first_line = atol(begin);
 317                                 cmd.last_line = atol(tmp + 1);
 318                                 break;
 319                         }
 320                         ++tmp;
 321                 }
 322
 323                 // which command to execute on this line(s)?
 324                 switch (end[-1]) {
 325                         case MODE_CHANGED:
 326                                 if (Debug == true)
 327                                         std::clog << "Change from line " << cmd.first_line << " to " << cmd.last_line << std::endl;
 328                                 break;
 329                         case MODE_ADDED:
 330                                 if (Debug == true)
 331                                         std::clog << "Insert after line " << cmd.first_line << std::endl;
 332                                 break;
 333                         case MODE_DELETED:
 334                                 if (Debug == true)
 335                                         std::clog << "Delete from line " << cmd.first_line << " to " << cmd.last_line << std::endl;
 336                                 break;
 337                         default:
 338                                 _error->Error("rred: Unknown ed command '%c'. Abort.", end[-1]);
 339                                 free(commands);
 340                                 return ED_PARSER;
 341                 }
 342                 cmd.type = end[-1];
 343
 344                 /* Determine the size of the inserted text, so we don't have to scan this
 345                  * text again later.
 346                  */
 347                 begin = end + 1;
 348                 end = begin;
 349                 cmd.data_lines = 0;
 350
 351                 if(cmd.type == MODE_ADDED || cmd.type == MODE_CHANGED) {
 352                         cmd.data_start = begin - (char*) ed_cmds.Data();
 353                         while(end != ed_end) {
 354                                 if(*end == '\n') {
 355                                         if(end[-1] == '.' && end[-2] == '\n')
 356                                                 break;
 357                                         ++cmd.data_lines;
 358                                 }
 359                                 ++end;
 360                         }
 361                         cmd.data_end = end - (char*) ed_cmds.Data() - 1;
 362                         begin = end + 1;
 363                         end = begin;
 364                 }
 365                 if(command_count == command_alloc) {
 366                         command_alloc = (command_alloc + 64) * 3 / 2;
 367                         commands = (EdCommand*) realloc(commands, command_alloc * sizeof(EdCommand));
 368                 }
 369                 commands[command_count++] = cmd;
 370         }
 371
 372         struct iovec* iov = new struct iovec[IOV_COUNT];
 373         size_t iov_size = 0;
 374
 375         size_t amount, remaining;
 376         size_t line = 1;
 377         EdCommand* cmd;
 378
 379         /* 2. Execute script.  We gather writes in a `struct iov' array, and flush
 380          *    using writev to minimize the number of system calls.  Data is read
 381          *    directly from the memory mappings of the input file and the script.
 382          */
 383
 384         for(i = command_count; i-- > 0; ) {
 385                 cmd = &commands[i];
 386                 if(cmd->type == MODE_ADDED)
 387                         amount = cmd->first_line + 1;
 388                 else
 389                         amount = cmd->first_line;
 390
 391                 if(line < amount) {
 392                         begin = input;
 393                         while(line != amount) {
 394                                 input = (const char*) memchr(input, '\n', input_end - input);
 395                                 if(!input)
 396                                         break;
 397                                 ++line;
 398                                 ++input;
 399                         }
 400
 401                         iov[iov_size].iov_base = (void*) begin;
 402                         iov[iov_size].iov_len = input - begin;
 403                         hash->Add((const unsigned char*) begin, input - begin);
 404
 405                         if(++iov_size == IOV_COUNT) {
 406                                 writev(out_file.Fd(), iov, IOV_COUNT);
 407                                 iov_size = 0;
 408                         }
 409                 }
 410
 411                 if(cmd->type == MODE_DELETED || cmd->type == MODE_CHANGED) {
 412                         remaining = (cmd->last_line - cmd->first_line) + 1;
 413                         line += remaining;
 414                         while(remaining) {
 415                                 input = (const char*) memchr(input, '\n', input_end - input);
 416                                 if(!input)
 417                                         break;
 418                                 --remaining;
 419                                 ++input;
 420                         }
 421                 }
 422
 423                 if(cmd->type == MODE_CHANGED || cmd->type == MODE_ADDED) {
 424                         if(cmd->data_end != cmd->data_start) {
 425                                 iov[iov_size].iov_base = (void*) ((char*)ed_cmds.Data() + cmd->data_start);
 426                                 iov[iov_size].iov_len = cmd->data_end - cmd->data_start;
 427                                 hash->Add((const unsigned char*) ((char*)ed_cmds.Data() + cmd->data_start),
 428                                 iov[iov_size].iov_len);
 429
 430                                 if(++iov_size == IOV_COUNT) {
 431                                         writev(out_file.Fd(), iov, IOV_COUNT);
 432                                         iov_size = 0;
 433                                 }
 434                         }
 435                 }
 436         }
 437
 438         if(input != input_end) {
 439                 iov[iov_size].iov_base = (void*) input;
 440                 iov[iov_size].iov_len = input_end - input;
 441                 hash->Add((const unsigned char*) input, input_end - input);
 442                 ++iov_size;
 443         }
 444
 445         if(iov_size) {
 446                 writev(out_file.Fd(), iov, iov_size);
 447                 iov_size = 0;
 448         }
 449
 450         for(i = 0; i < iov_size; i += IOV_COUNT) {
 451                 if(iov_size - i < IOV_COUNT)
 452                         writev(out_file.Fd(), iov + i, iov_size - i);
 453                 else
 454                         writev(out_file.Fd(), iov + i, IOV_COUNT);
 455         }
 456
 457         delete [] iov;
 458         free(commands);
 459
 460         return ED_OK;
 461 #else
 462         return MMAP_FAILED;
 463 #endif
 464 }
 465                                                                                 /*}}}*/
 466 bool RredMethod::Fetch(FetchItem *Itm)                                          /*{{{*/
 467 {
 468    Debug = _config->FindB("Debug::pkgAcquire::RRed", false);
 469    URI Get = Itm->Uri;
 470    string Path = Get.Host + Get.Path; // To account for relative paths
 471
 472    FetchResult Res;
 473    Res.Filename = Itm->DestFile;
 474    if (Itm->Uri.empty() == true) {
 475       Path = Itm->DestFile;
 476       Itm->DestFile.append(".result");
 477    } else
 478       URIStart(Res);
 479
 480    if (Debug == true)
 481       std::clog << "Patching " << Path << " with " << Path
 482          << ".ed and putting result into " << Itm->DestFile << std::endl;
 483    // Open the source and destination files (the d'tor of FileFd will do
 484    // the cleanup/closing of the fds)
 485    FileFd From(Path,FileFd::ReadOnly);
 486    FileFd Patch(Path+".ed",FileFd::ReadOnlyGzip);
 487    FileFd To(Itm->DestFile,FileFd::WriteAtomic);
 488    To.EraseOnFailure();
 489    if (_error->PendingError() == true)
 490       return false;
 491
 492    Hashes Hash;
 493    // now do the actual patching
 494    State const result = patchMMap(Patch, From, To, &Hash);
 495    if (result == MMAP_FAILED) {
 496       // retry with patchFile
 497       Patch.Seek(0);
 498       From.Seek(0);
 499       To.Open(Itm->DestFile,FileFd::WriteAtomic);
 500       if (_error->PendingError() == true)
 501          return false;
 502       if (patchFile(Patch, From, To, &Hash) != ED_OK) {
 503          return _error->WarningE("rred", _("Could not patch %s with mmap and with file operation usage - the patch seems to be corrupt."), Path.c_str());
 504       } else if (Debug == true) {
 505          std::clog << "rred: finished file patching of " << Path  << " after mmap failed." << std::endl;
 506       }
 507    } else if (result != ED_OK) {
 508       return _error->Errno("rred", _("Could not patch %s with mmap (but no mmap specific fail) - the patch seems to be corrupt."), Path.c_str());
 509    } else if (Debug == true) {
 510       std::clog << "rred: finished mmap patching of " << Path << std::endl;
 511    }
 512
 513    // write out the result
 514    From.Close();
 515    Patch.Close();
 516    To.Close();
 517
 518    /* Transfer the modification times from the patch file
 519       to be able to see in which state the file should be
 520       and use the access time from the "old" file */
 521    struct stat BufBase, BufPatch;
 522    if (stat(Path.c_str(),&BufBase) != 0 ||
 523        stat(string(Path+".ed").c_str(),&BufPatch) != 0)
 524       return _error->Errno("stat",_("Failed to stat"));
 525
 526    struct utimbuf TimeBuf;
 527    TimeBuf.actime = BufBase.st_atime;
 528    TimeBuf.modtime = BufPatch.st_mtime;
 529    if (utime(Itm->DestFile.c_str(),&TimeBuf) != 0)
 530       return _error->Errno("utime",_("Failed to set modification time"));
 531
 532    if (stat(Itm->DestFile.c_str(),&BufBase) != 0)
 533       return _error->Errno("stat",_("Failed to stat"));
 534
 535    // return done
 536    Res.LastModified = BufBase.st_mtime;
 537    Res.Size = BufBase.st_size;
 538    Res.TakeHashes(Hash);
 539    URIDone(Res);
 540
 541    return true;
 542 }
 543                                                                                 /*}}}*/
 544 /** \brief Wrapper class for testing rred */                                    /*{{{*/
 545 class TestRredMethod : public RredMethod {
 546 public:
 547         /** \brief Run rred in debug test mode
 548          *
 549          *  This method can be used to run the rred method outside
 550          *  of the "normal" acquire environment for easier testing.
 551          *
 552          *  \param base basename of all files involved in this rred test
 553          */
 554         bool Run(char const *base) {
 555                 _config->CndSet("Debug::pkgAcquire::RRed", "true");
 556                 FetchItem *test = new FetchItem;
 557                 test->DestFile = base;
 558                 return Fetch(test);
 559         }
 560 };
 561                                                                                 /*}}}*/
 562 /** \brief Starter for the rred method (or its test method)                     {{{
 563  *
 564  *  Used without parameters is the normal behavior for methods for
 565  *  the APT acquire system. While this works great for the acquire system
 566  *  it is very hard to test the method and therefore the method also
 567  *  accepts one parameter which will switch it directly to debug test mode:
 568  *  The test mode expects that if "Testfile" is given as parameter
 569  *  the file "Testfile" should be ed-style patched with "Testfile.ed"
 570  *  and will write the result to "Testfile.result".
 571  */
 572 int main(int argc, char *argv[]) {
 573         if (argc <= 1) {
 574                 RredMethod Mth;
 575                 return Mth.Run();
 576         } else {
 577                 TestRredMethod Mth;
 578                 bool result = Mth.Run(argv[1]);
 579                 _error->DumpErrors();
 580                 return result;
 581         }
 582 }
 583                                                                                 /*}}}*/