apt-inst/contrib/arfile.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: arfile.cc,v 1.5 2003/02/10 00:36:12 doogie Exp $
   4 /* ######################################################################
   5
   6    AR File - Handle an 'AR' archive
   7
   8    AR Archives have plain text headers at the start of each file
   9    section. The headers are aligned on a 2 byte boundry.
  10
  11    Information about the structure of AR files can be found in ar(5)
  12    on a BSD system, or in the binutils source.
  13
  14    ##################################################################### */
  15                                                                         /*}}}*/
  16 // Include Files                                                        /*{{{*/
  17 #ifdef __GNUG__
  18 #pragma implementation "apt-pkg/arfile.h"
  19 #endif
  20 #include <apti18n.h>
  21 #include <apt-pkg/arfile.h>
  22 #include <apt-pkg/strutl.h>
  23 #include <apt-pkg/error.h>
  24
  25 #include <stdlib.h>
  26                                                                         /*}}}*/
  27
  28 struct ARArchive::MemberHeader
  29 {
  30    char Name[16];
  31    char MTime[12];
  32    char UID[6];
  33    char GID[6];
  34    char Mode[8];
  35    char Size[10];
  36    char Magic[2];
  37 };
  38
  39 // ARArchive::ARArchive - Constructor                                   /*{{{*/
  40 // ---------------------------------------------------------------------
  41 /* */
  42 ARArchive::ARArchive(FileFd &File) : List(0), File(File)
  43 {
  44    LoadHeaders();
  45 }
  46                                                                         /*}}}*/
  47 // ARArchive::~ARArchive - Destructor                                   /*{{{*/
  48 // ---------------------------------------------------------------------
  49 /* */
  50 ARArchive::~ARArchive()
  51 {
  52    while (List != 0)
  53    {
  54       Member *Tmp = List;
  55       List = List->Next;
  56       delete Tmp;
  57    }
  58 }
  59                                                                         /*}}}*/
  60 // ARArchive::LoadHeaders - Load the headers from each file             /*{{{*/
  61 // ---------------------------------------------------------------------
  62 /* AR files are structured with a 8 byte magic string followed by a 60
  63    byte plain text header then the file data, another header, data, etc */
  64 bool ARArchive::LoadHeaders()
  65 {
  66    signed long Left = File.Size();
  67
  68    // Check the magic byte
  69    char Magic[8];
  70    if (File.Read(Magic,sizeof(Magic)) == false)
  71       return false;
  72    if (memcmp(Magic,"!<arch>\012",sizeof(Magic)) != 0)
  73       return _error->Error(_("Invalid archive signature"));
  74    Left -= sizeof(Magic);
  75
  76    // Read the member list
  77    while (Left > 0)
  78    {
  79       MemberHeader Head;
  80       if (File.Read(&Head,sizeof(Head)) == false)
  81          return _error->Error(_("Error reading archive member header"));
  82       Left -= sizeof(Head);
  83
  84       // Convert all of the integer members
  85       Member *Memb = new Member();
  86       if (StrToNum(Head.MTime,Memb->MTime,sizeof(Head.MTime)) == false ||
  87           StrToNum(Head.UID,Memb->UID,sizeof(Head.UID)) == false ||
  88           StrToNum(Head.GID,Memb->GID,sizeof(Head.GID)) == false ||
  89           StrToNum(Head.Mode,Memb->Mode,sizeof(Head.Mode),8) == false ||
  90           StrToNum(Head.Size,Memb->Size,sizeof(Head.Size)) == false)
  91       {
  92          delete Memb;
  93          return _error->Error(_("Invalid archive member header"));
  94       }
  95
  96       // Check for an extra long name string
  97       if (memcmp(Head.Name,"#1/",3) == 0)
  98       {
  99          char S[300];
 100          unsigned long Len;
 101          if (StrToNum(Head.Name+3,Len,sizeof(Head.Size)-3) == false ||
 102              Len >= strlen(S))
 103          {
 104             delete Memb;
 105             return _error->Error(_("Invalid archive member header"));
 106          }
 107          if (File.Read(S,Len) == false)
 108             return false;
 109          S[Len] = 0;
 110          Memb->Name = S;
 111          Memb->Size -= Len;
 112          Left -= Len;
 113       }
 114       else
 115       {
 116          unsigned int I = sizeof(Head.Name) - 1;
 117          for (; Head.Name[I] == ' '; I--);
 118          Memb->Name = string(Head.Name,0,I+1);
 119       }
 120
 121       // Account for the AR header alignment
 122       unsigned Skip = Memb->Size % 2;
 123
 124       // Add it to the list
 125       Memb->Next = List;
 126       List = Memb;
 127       Memb->Start = File.Tell();
 128       if (File.Skip(Memb->Size + Skip) == false)
 129          return false;
 130       if (Left < (signed)(Memb->Size + Skip))
 131          return _error->Error(_("Archive is too short"));
 132       Left -= Memb->Size + Skip;
 133    }
 134    if (Left != 0)
 135       return _error->Error(_("Failed to read the archive headers"));
 136
 137    return true;
 138 }
 139                                                                         /*}}}*/
 140 // ARArchive::FindMember - Find a name in the member list               /*{{{*/
 141 // ---------------------------------------------------------------------
 142 /* Find a member with the given name */
 143 const ARArchive::Member *ARArchive::FindMember(const char *Name) const
 144 {
 145    const Member *Res = List;
 146    while (Res != 0)
 147    {
 148       if (Res->Name == Name)
 149          return Res;
 150       Res = Res->Next;
 151    }
 152
 153    return 0;
 154 }
 155                                                                         /*}}}*/