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    // FIXME add an error message saying that empty files can't be valid archives
  60    if(From.Size() == 0)
  61       return false;
  62
  63    int GzOut[2];
  64    if (pipe(GzOut) < 0)
  65       return _error->Errno("pipe",_("Couldn't open pipe for %s"),Prog);
  66
  67    // Fork bzip2
  68    pid_t Process = ExecFork();
  69    if (Process == 0)
  70    {
  71       close(GzOut[0]);
  72       dup2(From.Fd(),STDIN_FILENO);
  73       dup2(GzOut[1],STDOUT_FILENO);
  74       From.Close();
  75       close(GzOut[1]);
  76       SetCloseExec(STDIN_FILENO,false);
  77       SetCloseExec(STDOUT_FILENO,false);
  78
  79       const char *Args[3];
  80       string Tmp = _config->Find(GzPathOption,Prog);
  81       Args[0] = Tmp.c_str();
  82       Args[1] = "-d";
  83       Args[2] = 0;
  84       execvp(Args[0],(char **)Args);
  85       _exit(100);
  86    }
  87    From.Close();
  88    close(GzOut[1]);
  89
  90    FileFd FromGz(GzOut[0]);  // For autoclose
  91    FileFd To(Itm->DestFile,FileFd::WriteAtomic);
  92    To.EraseOnFailure();
  93    if (_error->PendingError() == true)
  94       return false;
  95
  96    // Read data from bzip2, generate checksums and write
  97    Hashes Hash;
  98    bool Failed = false;
  99    while (1)
 100    {
 101       unsigned char Buffer[4*1024];
 102
 103       ssize_t Count = read(GzOut[0],Buffer,sizeof(Buffer));
 104       if (Count < 0 && errno == EINTR)
 105          continue;
 106
 107       if (Count < 0)
 108       {
 109          _error->Errno("read", _("Read error from %s process"),Prog);
 110          Failed = true;
 111          break;
 112       }
 113
 114       if (Count == 0)
 115          break;
 116
 117       Hash.Add(Buffer,Count);
 118       if (To.Write(Buffer,Count) == false)
 119       {
 120          Failed = true;
 121          FromGz.Close();
 122          break;
 123       }
 124    }
 125
 126    // Wait for bzip2 to finish
 127    if (ExecWait(Process,_config->Find(GzPathOption,Prog).c_str(),false) == false)
 128    {
 129       To.OpFail();
 130       return false;
 131    }
 132
 133    To.Close();
 134
 135    if (Failed == true)
 136       return false;
 137
 138    // Transfer the modification times
 139    struct stat Buf;
 140    if (stat(Path.c_str(),&Buf) != 0)
 141       return _error->Errno("stat",_("Failed to stat"));
 142
 143    struct utimbuf TimeBuf;
 144    TimeBuf.actime = Buf.st_atime;
 145    TimeBuf.modtime = Buf.st_mtime;
 146    if (utime(Itm->DestFile.c_str(),&TimeBuf) != 0)
 147       return _error->Errno("utime",_("Failed to set modification time"));
 148
 149    if (stat(Itm->DestFile.c_str(),&Buf) != 0)
 150       return _error->Errno("stat",_("Failed to stat"));
 151
 152    // Return a Done response
 153    Res.LastModified = Buf.st_mtime;
 154    Res.Size = Buf.st_size;
 155    Res.TakeHashes(Hash);
 156
 157    URIDone(Res);
 158
 159    return true;
 160 }
 161                                                                         /*}}}*/
 162
 163 int main(int argc, char *argv[])
 164 {
 165    setlocale(LC_ALL, "");
 166
 167    Bzip2Method Mth;
 168
 169    Prog = strrchr(argv[0],'/');
 170    Prog++;
 171
 172    return Mth.Run();
 173 }