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(0, mapSize, 0);
 259                 gzread(Patch.gzFd(), dyn.Data(), mapSize);
 260                 ed_cmds = dyn;
 261         } else
 262                 ed_cmds = MMap(Patch, MMap::ReadOnly);
 263
 264         MMap in_file(From, MMap::ReadOnly);
 265
 266         if (ed_cmds.Size() == 0 || in_file.Size() == 0)
 267                 return MMAP_FAILED;
 268
 269         EdCommand* commands = 0;
 270         size_t command_count = 0;
 271         size_t command_alloc = 0;
 272
 273         const char* begin = (char*) ed_cmds.Data();
 274         const char* end = begin;
 275         const char* ed_end = (char*) ed_cmds.Data() + ed_cmds.Size();
 276
 277         const char* input = (char*) in_file.Data();
 278         const char* input_end = (char*) in_file.Data() + in_file.Size();
 279
 280         size_t i;
 281
 282         /* 1. Parse entire script.  It is executed in reverse order, so we cather it
 283          *    in the `commands' buffer first
 284          */
 285
 286         for(;;) {
 287                 EdCommand cmd;
 288                 cmd.data_start = 0;
 289                 cmd.data_end = 0;
 290
 291                 while(begin != ed_end && *begin == '\n')
 292                         ++begin;
 293                 while(end != ed_end && *end != '\n')
 294                         ++end;
 295                 if(end == ed_end && begin == end)
 296                         break;
 297
 298                 /* Determine command range */
 299                 const char* tmp = begin;
 300
 301                 for(;;) {
 302                         /* atoll is safe despite lacking NUL-termination; we know there's an
 303                          * alphabetic character at end[-1]
 304                          */
 305                         if(tmp == end) {
 306                                 cmd.first_line = atol(begin);
 307                                 cmd.last_line = cmd.first_line;
 308                                 break;
 309                         }
 310                         if(*tmp == ',') {
 311                                 cmd.first_line = atol(begin);
 312                                 cmd.last_line = atol(tmp + 1);
 313                                 break;
 314                         }
 315                         ++tmp;
 316                 }
 317
 318                 // which command to execute on this line(s)?
 319                 switch (end[-1]) {
 320                         case MODE_CHANGED:
 321                                 if (Debug == true)
 322                                         std::clog << "Change from line " << cmd.first_line << " to " << cmd.last_line << std::endl;
 323                                 break;
 324                         case MODE_ADDED:
 325                                 if (Debug == true)
 326                                         std::clog << "Insert after line " << cmd.first_line << std::endl;
 327                                 break;
 328                         case MODE_DELETED:
 329                                 if (Debug == true)
 330                                         std::clog << "Delete from line " << cmd.first_line << " to " << cmd.last_line << std::endl;
 331                                 break;
 332                         default:
 333                                 _error->Error("rred: Unknown ed command '%c'. Abort.", end[-1]);
 334                                 free(commands);
 335                                 return ED_PARSER;
 336                 }
 337                 cmd.type = end[-1];
 338
 339                 /* Determine the size of the inserted text, so we don't have to scan this
 340                  * text again later.
 341                  */
 342                 begin = end + 1;
 343                 end = begin;
 344                 cmd.data_lines = 0;
 345
 346                 if(cmd.type == MODE_ADDED || cmd.type == MODE_CHANGED) {
 347                         cmd.data_start = begin - (char*) ed_cmds.Data();
 348                         while(end != ed_end) {
 349                                 if(*end == '\n') {
 350                                         if(end[-1] == '.' && end[-2] == '\n')
 351                                                 break;
 352                                         ++cmd.data_lines;
 353                                 }
 354                                 ++end;
 355                         }
 356                         cmd.data_end = end - (char*) ed_cmds.Data() - 1;
 357                         begin = end + 1;
 358                         end = begin;
 359                 }
 360                 if(command_count == command_alloc) {
 361                         command_alloc = (command_alloc + 64) * 3 / 2;
 362                         commands = (EdCommand*) realloc(commands, command_alloc * sizeof(EdCommand));
 363                 }
 364                 commands[command_count++] = cmd;
 365         }
 366
 367         struct iovec* iov = new struct iovec[IOV_COUNT];
 368         size_t iov_size = 0;
 369
 370         size_t amount, remaining;
 371         size_t line = 1;
 372         EdCommand* cmd;
 373
 374         /* 2. Execute script.  We gather writes in a `struct iov' array, and flush
 375          *    using writev to minimize the number of system calls.  Data is read
 376          *    directly from the memory mappings of the input file and the script.
 377          */
 378
 379         for(i = command_count; i-- > 0; ) {
 380                 cmd = &commands[i];
 381                 if(cmd->type == MODE_ADDED)
 382                         amount = cmd->first_line + 1;
 383                 else
 384                         amount = cmd->first_line;
 385
 386                 if(line < amount) {
 387                         begin = input;
 388                         while(line != amount) {
 389                                 input = (const char*) memchr(input, '\n', input_end - input);
 390                                 if(!input)
 391                                         break;
 392                                 ++line;
 393                                 ++input;
 394                         }
 395
 396                         iov[iov_size].iov_base = (void*) begin;
 397                         iov[iov_size].iov_len = input - begin;
 398                         hash->Add((const unsigned char*) begin, input - begin);
 399
 400                         if(++iov_size == IOV_COUNT) {
 401                                 writev(out_file.Fd(), iov, IOV_COUNT);
 402                                 iov_size = 0;
 403                         }
 404                 }
 405
 406                 if(cmd->type == MODE_DELETED || cmd->type == MODE_CHANGED) {
 407                         remaining = (cmd->last_line - cmd->first_line) + 1;
 408                         line += remaining;
 409                         while(remaining) {
 410                                 input = (const char*) memchr(input, '\n', input_end - input);
 411                                 if(!input)
 412                                         break;
 413                                 --remaining;
 414                                 ++input;
 415                         }
 416                 }
 417
 418                 if(cmd->type == MODE_CHANGED || cmd->type == MODE_ADDED) {
 419                         if(cmd->data_end != cmd->data_start) {
 420                                 iov[iov_size].iov_base = (void*) ((char*)ed_cmds.Data() + cmd->data_start);
 421                                 iov[iov_size].iov_len = cmd->data_end - cmd->data_start;
 422                                 hash->Add((const unsigned char*) ((char*)ed_cmds.Data() + cmd->data_start),
 423                                 iov[iov_size].iov_len);
 424
 425                                 if(++iov_size == IOV_COUNT) {
 426                                         writev(out_file.Fd(), iov, IOV_COUNT);
 427                                         iov_size = 0;
 428                                 }
 429                         }
 430                 }
 431         }
 432
 433         if(input != input_end) {
 434                 iov[iov_size].iov_base = (void*) input;
 435                 iov[iov_size].iov_len = input_end - input;
 436                 hash->Add((const unsigned char*) input, input_end - input);
 437                 ++iov_size;
 438         }
 439
 440         if(iov_size) {
 441                 writev(out_file.Fd(), iov, iov_size);
 442                 iov_size = 0;
 443         }
 444
 445         for(i = 0; i < iov_size; i += IOV_COUNT) {
 446                 if(iov_size - i < IOV_COUNT)
 447                         writev(out_file.Fd(), iov + i, iov_size - i);
 448                 else
 449                         writev(out_file.Fd(), iov + i, IOV_COUNT);
 450         }
 451
 452         delete [] iov;
 453         free(commands);
 454
 455         return ED_OK;
 456 #else
 457         return MMAP_FAILED;
 458 #endif
 459 }
 460                                                                                 /*}}}*/
 461 bool RredMethod::Fetch(FetchItem *Itm)                                          /*{{{*/
 462 {
 463    Debug = _config->FindB("Debug::pkgAcquire::RRed", false);
 464    URI Get = Itm->Uri;
 465    string Path = Get.Host + Get.Path; // To account for relative paths
 466
 467    FetchResult Res;
 468    Res.Filename = Itm->DestFile;
 469    if (Itm->Uri.empty() == true) {
 470       Path = Itm->DestFile;
 471       Itm->DestFile.append(".result");
 472    } else
 473       URIStart(Res);
 474
 475    if (Debug == true)
 476       std::clog << "Patching " << Path << " with " << Path
 477          << ".ed and putting result into " << Itm->DestFile << std::endl;
 478    // Open the source and destination files (the d'tor of FileFd will do
 479    // the cleanup/closing of the fds)
 480    FileFd From(Path,FileFd::ReadOnly);
 481    FileFd Patch(Path+".ed",FileFd::ReadOnlyGzip);
 482    FileFd To(Itm->DestFile,FileFd::WriteAtomic);
 483    To.EraseOnFailure();
 484    if (_error->PendingError() == true)
 485       return false;
 486
 487    Hashes Hash;
 488    // now do the actual patching
 489    State const result = patchMMap(Patch, From, To, &Hash);
 490    if (result == MMAP_FAILED) {
 491       // retry with patchFile
 492       Patch.Seek(0);
 493       From.Seek(0);
 494       To.Open(Itm->DestFile,FileFd::WriteAtomic);
 495       if (_error->PendingError() == true)
 496          return false;
 497       if (patchFile(Patch, From, To, &Hash) != ED_OK) {
 498          return _error->WarningE("rred", _("Could not patch %s with mmap and with file operation usage - the patch seems to be corrupt."), Path.c_str());
 499       } else if (Debug == true) {
 500          std::clog << "rred: finished file patching of " << Path  << " after mmap failed." << std::endl;
 501       }
 502    } else if (result != ED_OK) {
 503       return _error->Errno("rred", _("Could not patch %s with mmap (but no mmap specific fail) - the patch seems to be corrupt."), Path.c_str());
 504    } else if (Debug == true) {
 505       std::clog << "rred: finished mmap patching of " << Path << std::endl;
 506    }
 507
 508    // write out the result
 509    From.Close();
 510    Patch.Close();
 511    To.Close();
 512
 513    /* Transfer the modification times from the patch file
 514       to be able to see in which state the file should be
 515       and use the access time from the "old" file */
 516    struct stat BufBase, BufPatch;
 517    if (stat(Path.c_str(),&BufBase) != 0 ||
 518        stat(string(Path+".ed").c_str(),&BufPatch) != 0)
 519       return _error->Errno("stat",_("Failed to stat"));
 520
 521    struct utimbuf TimeBuf;
 522    TimeBuf.actime = BufBase.st_atime;
 523    TimeBuf.modtime = BufPatch.st_mtime;
 524    if (utime(Itm->DestFile.c_str(),&TimeBuf) != 0)
 525       return _error->Errno("utime",_("Failed to set modification time"));
 526
 527    if (stat(Itm->DestFile.c_str(),&BufBase) != 0)
 528       return _error->Errno("stat",_("Failed to stat"));
 529
 530    // return done
 531    Res.LastModified = BufBase.st_mtime;
 532    Res.Size = BufBase.st_size;
 533    Res.TakeHashes(Hash);
 534    URIDone(Res);
 535
 536    return true;
 537 }
 538                                                                                 /*}}}*/
 539 /** \brief Wrapper class for testing rred */                                    /*{{{*/
 540 class TestRredMethod : public RredMethod {
 541 public:
 542         /** \brief Run rred in debug test mode
 543          *
 544          *  This method can be used to run the rred method outside
 545          *  of the "normal" acquire environment for easier testing.
 546          *
 547          *  \param base basename of all files involved in this rred test
 548          */
 549         bool Run(char const *base) {
 550                 _config->CndSet("Debug::pkgAcquire::RRed", "true");
 551                 FetchItem *test = new FetchItem;
 552                 test->DestFile = base;
 553                 return Fetch(test);
 554         }
 555 };
 556                                                                                 /*}}}*/
 557 /** \brief Starter for the rred method (or its test method)                     {{{
 558  *
 559  *  Used without parameters is the normal behavior for methods for
 560  *  the APT acquire system. While this works great for the acquire system
 561  *  it is very hard to test the method and therefore the method also
 562  *  accepts one parameter which will switch it directly to debug test mode:
 563  *  The test mode expects that if "Testfile" is given as parameter
 564  *  the file "Testfile" should be ed-style patched with "Testfile.ed"
 565  *  and will write the result to "Testfile.result".
 566  */
 567 int main(int argc, char *argv[]) {
 568         if (argc <= 1) {
 569                 RredMethod Mth;
 570                 return Mth.Run();
 571         } else {
 572                 TestRredMethod Mth;
 573                 bool result = Mth.Run(argv[1]);
 574                 _error->DumpErrors();
 575                 return result;
 576         }
 577 }
 578                                                                                 /*}}}*/