apt-inst/deb/debfile.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: debfile.cc,v 1.3.2.1 2004/01/16 18:58:50 mdz Exp $
   4 /* ######################################################################
   5
   6    Debian Archive File (.deb)
   7
   8    .DEB archives are AR files containing two tars and an empty marker
   9    member called 'debian-binary'. The two tars contain the meta data and
  10    the actual archive contents. Thus this class is a very simple wrapper
  11    around ar/tar to simply extract the right tar files.
  12
  13    It also uses the deb package list parser to parse the control file
  14    into the cache.
  15
  16    ##################################################################### */
  17                                                                         /*}}}*/
  18 // Include Files                                                        /*{{{*/
  19 #ifdef __GNUG__
  20 #pragma implementation "apt-pkg/debfile.h"
  21 #endif
  22
  23 #include <apt-pkg/debfile.h>
  24 #include <apt-pkg/extracttar.h>
  25 #include <apt-pkg/error.h>
  26 #include <apt-pkg/deblistparser.h>
  27
  28 #include <sys/stat.h>
  29 #include <unistd.h>
  30 #include <apti18n.h>
  31                                                                         /*}}}*/
  32
  33 // DebFile::debDebFile - Constructor                                    /*{{{*/
  34 // ---------------------------------------------------------------------
  35 /* Open the AR file and check for consistency */
  36 debDebFile::debDebFile(FileFd &File) : File(File), AR(File)
  37 {
  38    if (_error->PendingError() == true)
  39       return;
  40
  41    if (!CheckMember("debian-binary")) {
  42       _error->Error(_("This is not a valid DEB archive, missing '%s' member"), "debian-binary");
  43       return;
  44    }
  45
  46    if (!CheckMember("control.tar.gz")) {
  47       _error->Error(_("This is not a valid DEB archive, missing '%s' member"), "control.tar.gz");
  48       return;
  49    }
  50
  51    if (!CheckMember("data.tar.gz") && !CheckMember("data.tar.bz2")) {
  52       _error->Error(_("This is not a valid DEB archive, it has no '%s' or '%s' member"), "data.tar.gz", "data.tar.bz2");
  53       return;
  54    }
  55 }
  56                                                                         /*}}}*/
  57 // DebFile::CheckMember - Check if a named member is in the archive     /*{{{*/
  58 // ---------------------------------------------------------------------
  59 /* This is used to check for a correct deb and to give nicer error messages
  60    for people playing around. */
  61 bool debDebFile::CheckMember(const char *Name)
  62 {
  63    if (AR.FindMember(Name) == 0)
  64       return false;
  65    return true;
  66 }
  67                                                                         /*}}}*/
  68 // DebFile::GotoMember - Jump to a Member                               /*{{{*/
  69 // ---------------------------------------------------------------------
  70 /* Jump in the file to the start of a named member and return the information
  71    about that member. The caller can then read from the file up to the
  72    returned size. Note, since this relies on the file position this is
  73    a destructive operation, it also changes the last returned Member
  74    structure - so don't nest them! */
  75 const ARArchive::Member *debDebFile::GotoMember(const char *Name)
  76 {
  77    // Get the archive member and positition the file
  78    const ARArchive::Member *Member = AR.FindMember(Name);
  79    if (Member == 0)
  80    {
  81       return 0;
  82    }
  83    if (File.Seek(Member->Start) == false)
  84       return 0;
  85
  86    return Member;
  87 }
  88                                                                         /*}}}*/
  89 // DebFile::ExtractControl - Extract Control information                /*{{{*/
  90 // ---------------------------------------------------------------------
  91 /* Extract the control information into the Database's temporary
  92    directory. */
  93 bool debDebFile::ExtractControl(pkgDataBase &DB)
  94 {
  95    // Get the archive member and positition the file
  96    const ARArchive::Member *Member = GotoMember("control.tar.gz");
  97    if (Member == 0)
  98       return false;
  99
 100    // Prepare Tar
 101    ControlExtract Extract;
 102    ExtractTar Tar(File,Member->Size,"gzip");
 103    if (_error->PendingError() == true)
 104       return false;
 105
 106    // Get into the temporary directory
 107    string Cwd = SafeGetCWD();
 108    string Tmp;
 109    if (DB.GetMetaTmp(Tmp) == false)
 110       return false;
 111    if (chdir(Tmp.c_str()) != 0)
 112       return _error->Errno("chdir",_("Couldn't change to %s"),Tmp.c_str());
 113
 114    // Do extraction
 115    if (Tar.Go(Extract) == false)
 116       return false;
 117
 118    // Switch out of the tmp directory.
 119    if (chdir(Cwd.c_str()) != 0)
 120       chdir("/");
 121
 122    return true;
 123 }
 124                                                                         /*}}}*/
 125 // DebFile::ExtractArchive - Extract the archive data itself            /*{{{*/
 126 // ---------------------------------------------------------------------
 127 /* Simple wrapper around tar.. */
 128 bool debDebFile::ExtractArchive(pkgDirStream &Stream)
 129 {
 130    // Get the archive member and positition the file
 131    const ARArchive::Member *Member = AR.FindMember("data.tar.gz");
 132    const char *Compressor = "gzip";
 133    if (Member == 0) {
 134       Member = AR.FindMember("data.tar.bz2");
 135       Compressor = "bzip2";
 136    }
 137    if (Member == 0)
 138       return _error->Error(_("Internal error, could not locate member"));
 139    if (File.Seek(Member->Start) == false)
 140       return false;
 141
 142    // Prepare Tar
 143    ExtractTar Tar(File,Member->Size,Compressor);
 144    if (_error->PendingError() == true)
 145       return false;
 146    return Tar.Go(Stream);
 147 }
 148                                                                         /*}}}*/
 149 // DebFile::MergeControl - Merge the control information                /*{{{*/
 150 // ---------------------------------------------------------------------
 151 /* This reads the extracted control file into the cache and returns the
 152    version that was parsed. All this really does is select the correct
 153    parser and correct file to parse. */
 154 pkgCache::VerIterator debDebFile::MergeControl(pkgDataBase &DB)
 155 {
 156    // Open the control file
 157    string Tmp;
 158    if (DB.GetMetaTmp(Tmp) == false)
 159       return pkgCache::VerIterator(DB.GetCache());
 160    FileFd Fd(Tmp + "control",FileFd::ReadOnly);
 161    if (_error->PendingError() == true)
 162       return pkgCache::VerIterator(DB.GetCache());
 163
 164    // Parse it
 165    debListParser Parse(&Fd);
 166    pkgCache::VerIterator Ver(DB.GetCache());
 167    if (DB.GetGenerator().MergeList(Parse,&Ver) == false)
 168       return pkgCache::VerIterator(DB.GetCache());
 169
 170    if (Ver.end() == true)
 171       _error->Error(_("Failed to locate a valid control file"));
 172    return Ver;
 173 }
 174                                                                         /*}}}*/
 175
 176 // DebFile::ControlExtract::DoItem - Control Tar Extraction             /*{{{*/
 177 // ---------------------------------------------------------------------
 178 /* This directory stream handler for the control tar handles extracting
 179    it into the temporary meta directory. It only extracts files, it does
 180    not create directories, links or anything else. */
 181 bool debDebFile::ControlExtract::DoItem(Item &Itm,int &Fd)
 182 {
 183    if (Itm.Type != Item::File)
 184       return true;
 185
 186    /* Cleanse the file name, prevent people from trying to unpack into
 187       absolute paths, .., etc */
 188    for (char *I = Itm.Name; *I != 0; I++)
 189       if (*I == '/')
 190          *I = '_';
 191
 192    /* Force the ownership to be root and ensure correct permissions,
 193       go-w, the rest are left untouched */
 194    Itm.UID = 0;
 195    Itm.GID = 0;
 196    Itm.Mode &= ~(S_IWGRP | S_IWOTH);
 197
 198    return pkgDirStream::DoItem(Itm,Fd);
 199 }
 200                                                                         /*}}}*/
 201
 202 // MemControlExtract::DoItem - Check if it is the control file          /*{{{*/
 203 // ---------------------------------------------------------------------
 204 /* This sets up to extract the control block member file into a memory
 205    block of just the right size. All other files go into the bit bucket. */
 206 bool debDebFile::MemControlExtract::DoItem(Item &Itm,int &Fd)
 207 {
 208    // At the control file, allocate buffer memory.
 209    if (Member == Itm.Name)
 210    {
 211       delete [] Control;
 212       Control = new char[Itm.Size+2];
 213       IsControl = true;
 214       Fd = -2; // Signal to pass to Process
 215       Length = Itm.Size;
 216    }
 217    else
 218       IsControl = false;
 219
 220    return true;
 221 }
 222                                                                         /*}}}*/
 223 // MemControlExtract::Process - Process extracting the control file     /*{{{*/
 224 // ---------------------------------------------------------------------
 225 /* Just memcopy the block from the tar extractor and put it in the right
 226    place in the pre-allocated memory block. */
 227 bool debDebFile::MemControlExtract::Process(Item &Itm,const unsigned char *Data,
 228                              unsigned long Size,unsigned long Pos)
 229 {
 230    memcpy(Control + Pos, Data,Size);
 231    return true;
 232 }
 233                                                                         /*}}}*/
 234 // MemControlExtract::Read - Read the control information from the deb  /*{{{*/
 235 // ---------------------------------------------------------------------
 236 /* This uses the internal tar extractor to fetch the control file, and then
 237    it parses it into a tag section parser. */
 238 bool debDebFile::MemControlExtract::Read(debDebFile &Deb)
 239 {
 240    // Get the archive member and positition the file
 241    const ARArchive::Member *Member = Deb.GotoMember("control.tar.gz");
 242    if (Member == 0)
 243       return false;
 244
 245    // Extract it.
 246    ExtractTar Tar(Deb.GetFile(),Member->Size,"gzip");
 247    if (Tar.Go(*this) == false)
 248       return false;
 249
 250    if (Control == 0)
 251       return true;
 252
 253    Control[Length] = '\n';
 254    Control[Length+1] = '\n';
 255    if (Section.Scan(Control,Length+2) == false)
 256       return _error->Error(_("Unparsable control file"));
 257    return true;
 258 }
 259                                                                         /*}}}*/
 260 // MemControlExtract::TakeControl - Parse a memory block                /*{{{*/
 261 // ---------------------------------------------------------------------
 262 /* The given memory block is loaded into the parser and parsed as a control
 263    record. */
 264 bool debDebFile::MemControlExtract::TakeControl(const void *Data,unsigned long Size)
 265 {
 266    delete [] Control;
 267    Control = new char[Size+2];
 268    Length = Size;
 269    memcpy(Control,Data,Size);
 270
 271    Control[Length] = '\n';
 272    Control[Length+1] = '\n';
 273    return Section.Scan(Control,Length+2);
 274 }
 275                                                                         /*}}}*/
 276