methods/bzip2.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 /* ######################################################################
   4
   5    Bzip2 method - Take a file URI in and decompress it into the target
   6    file.
   7
   8    While the method is named "bzip2" it handles also other compression
   9    types as it calls binaries based on the name of the method,
  10    so it can also be used to handle gzip, lzma and others if named
  11    correctly.
  12
  13    ##################################################################### */
  14                                                                         /*}}}*/
  15 // Include Files                                                        /*{{{*/
  16 #include <apt-pkg/fileutl.h>
  17 #include <apt-pkg/error.h>
  18 #include <apt-pkg/acquire-method.h>
  19 #include <apt-pkg/strutl.h>
  20 #include <apt-pkg/hashes.h>
  21
  22 #include <sys/stat.h>
  23 #include <unistd.h>
  24 #include <utime.h>
  25 #include <stdio.h>
  26 #include <errno.h>
  27 #include <apti18n.h>
  28                                                                         /*}}}*/
  29
  30 const char *Prog;
  31
  32 class Bzip2Method : public pkgAcqMethod
  33 {
  34    virtual bool Fetch(FetchItem *Itm);
  35
  36    public:
  37
  38    Bzip2Method() : pkgAcqMethod("1.1",SingleInstance | SendConfig) {};
  39 };
  40
  41
  42 // Bzip2Method::Fetch - Decompress the passed URI                       /*{{{*/
  43 // ---------------------------------------------------------------------
  44 /* */
  45 bool Bzip2Method::Fetch(FetchItem *Itm)
  46 {
  47    URI Get = Itm->Uri;
  48    string Path = Get.Host + Get.Path; // To account for relative paths
  49
  50    string GzPathOption = "Dir::bin::"+string(Prog);
  51
  52    FetchResult Res;
  53    Res.Filename = Itm->DestFile;
  54    URIStart(Res);
  55
  56    // Open the source and destination files
  57    FileFd From(Path,FileFd::ReadOnly);
  58
  59    // if the file is empty, just rename it and return
  60    if(From.Size() == 0)
  61    {
  62       rename(Path.c_str(), Itm->DestFile.c_str());
  63       return true;
  64    }
  65
  66    int GzOut[2];
  67    if (pipe(GzOut) < 0)
  68       return _error->Errno("pipe",_("Couldn't open pipe for %s"),Prog);
  69
  70    // Fork bzip2
  71    pid_t Process = ExecFork();
  72    if (Process == 0)
  73    {
  74       close(GzOut[0]);
  75       dup2(From.Fd(),STDIN_FILENO);
  76       dup2(GzOut[1],STDOUT_FILENO);
  77       From.Close();
  78       close(GzOut[1]);
  79       SetCloseExec(STDIN_FILENO,false);
  80       SetCloseExec(STDOUT_FILENO,false);
  81
  82       const char *Args[3];
  83       string Tmp = _config->Find(GzPathOption,Prog);
  84       Args[0] = Tmp.c_str();
  85       Args[1] = "-d";
  86       Args[2] = 0;
  87       execvp(Args[0],(char **)Args);
  88       _exit(100);
  89    }
  90    From.Close();
  91    close(GzOut[1]);
  92
  93    FileFd FromGz(GzOut[0]);  // For autoclose
  94    FileFd To(Itm->DestFile,FileFd::WriteAtomic);
  95    To.EraseOnFailure();
  96    if (_error->PendingError() == true)
  97       return false;
  98
  99    // Read data from bzip2, generate checksums and write
 100    Hashes Hash;
 101    bool Failed = false;
 102    while (1)
 103    {
 104       unsigned char Buffer[4*1024];
 105
 106       ssize_t Count = read(GzOut[0],Buffer,sizeof(Buffer));
 107       if (Count < 0 && errno == EINTR)
 108          continue;
 109
 110       if (Count < 0)
 111       {
 112          _error->Errno("read", _("Read error from %s process"),Prog);
 113          Failed = true;
 114          break;
 115       }
 116
 117       if (Count == 0)
 118          break;
 119
 120       Hash.Add(Buffer,Count);
 121       if (To.Write(Buffer,Count) == false)
 122       {
 123          Failed = true;
 124          FromGz.Close();
 125          break;
 126       }
 127    }
 128
 129    // Wait for bzip2 to finish
 130    if (ExecWait(Process,_config->Find(GzPathOption,Prog).c_str(),false) == false)
 131    {
 132       To.OpFail();
 133       return false;
 134    }
 135
 136    To.Close();
 137
 138    if (Failed == true)
 139       return false;
 140
 141    // Transfer the modification times
 142    struct stat Buf;
 143    if (stat(Path.c_str(),&Buf) != 0)
 144       return _error->Errno("stat",_("Failed to stat"));
 145
 146    struct utimbuf TimeBuf;
 147    TimeBuf.actime = Buf.st_atime;
 148    TimeBuf.modtime = Buf.st_mtime;
 149    if (utime(Itm->DestFile.c_str(),&TimeBuf) != 0)
 150       return _error->Errno("utime",_("Failed to set modification time"));
 151
 152    if (stat(Itm->DestFile.c_str(),&Buf) != 0)
 153       return _error->Errno("stat",_("Failed to stat"));
 154
 155    // Return a Done response
 156    Res.LastModified = Buf.st_mtime;
 157    Res.Size = Buf.st_size;
 158    Res.TakeHashes(Hash);
 159
 160    URIDone(Res);
 161
 162    return true;
 163 }
 164                                                                         /*}}}*/
 165
 166 int main(int argc, char *argv[])
 167 {
 168    setlocale(LC_ALL, "");
 169
 170    Bzip2Method Mth;
 171
 172    Prog = strrchr(argv[0],'/');
 173    Prog++;
 174
 175    return Mth.Run();
 176 }