apt-inst/contrib/arfile.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: arfile.cc,v 1.6.2.1 2004/01/16 18:58:50 mdz 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 #include <apt-pkg/arfile.h>
  18 #include <apt-pkg/strutl.h>
  19 #include <apt-pkg/error.h>
  20
  21 #include <stdlib.h>
  22                                                                         /*}}}*/
  23 #include <apti18n.h>
  24
  25 struct ARArchive::MemberHeader
  26 {
  27    char Name[16];
  28    char MTime[12];
  29    char UID[6];
  30    char GID[6];
  31    char Mode[8];
  32    char Size[10];
  33    char Magic[2];
  34 };
  35
  36 // ARArchive::ARArchive - Constructor                                   /*{{{*/
  37 // ---------------------------------------------------------------------
  38 /* */
  39 ARArchive::ARArchive(FileFd &File) : List(0), File(File)
  40 {
  41    LoadHeaders();
  42 }
  43                                                                         /*}}}*/
  44 // ARArchive::~ARArchive - Destructor                                   /*{{{*/
  45 // ---------------------------------------------------------------------
  46 /* */
  47 ARArchive::~ARArchive()
  48 {
  49    while (List != 0)
  50    {
  51       Member *Tmp = List;
  52       List = List->Next;
  53       delete Tmp;
  54    }
  55 }
  56                                                                         /*}}}*/
  57 // ARArchive::LoadHeaders - Load the headers from each file             /*{{{*/
  58 // ---------------------------------------------------------------------
  59 /* AR files are structured with a 8 byte magic string followed by a 60
  60    byte plain text header then the file data, another header, data, etc */
  61 bool ARArchive::LoadHeaders()
  62 {
  63    signed long Left = File.Size();
  64
  65    // Check the magic byte
  66    char Magic[8];
  67    if (File.Read(Magic,sizeof(Magic)) == false)
  68       return false;
  69    if (memcmp(Magic,"!<arch>\012",sizeof(Magic)) != 0)
  70       return _error->Error(_("Invalid archive signature"));
  71    Left -= sizeof(Magic);
  72
  73    // Read the member list
  74    while (Left > 0)
  75    {
  76       MemberHeader Head;
  77       if (File.Read(&Head,sizeof(Head)) == false)
  78          return _error->Error(_("Error reading archive member header"));
  79       Left -= sizeof(Head);
  80
  81       // Convert all of the integer members
  82       Member *Memb = new Member();
  83       if (StrToNum(Head.MTime,Memb->MTime,sizeof(Head.MTime)) == false ||
  84           StrToNum(Head.UID,Memb->UID,sizeof(Head.UID)) == false ||
  85           StrToNum(Head.GID,Memb->GID,sizeof(Head.GID)) == false ||
  86           StrToNum(Head.Mode,Memb->Mode,sizeof(Head.Mode),8) == false ||
  87           StrToNum(Head.Size,Memb->Size,sizeof(Head.Size)) == false)
  88       {
  89          delete Memb;
  90          return _error->Error(_("Invalid archive member header %s"), Head.Name);
  91       }
  92
  93       // Check for an extra long name string
  94       if (memcmp(Head.Name,"#1/",3) == 0)
  95       {
  96          char S[300];
  97          unsigned long Len;
  98          if (StrToNum(Head.Name+3,Len,sizeof(Head.Size)-3) == false ||
  99              Len >= sizeof(S))
 100          {
 101             delete Memb;
 102             return _error->Error(_("Invalid archive member header"));
 103          }
 104          if (File.Read(S,Len) == false)
 105             return false;
 106          S[Len] = 0;
 107          Memb->Name = S;
 108          Memb->Size -= Len;
 109          Left -= Len;
 110       }
 111       else
 112       {
 113          unsigned int I = sizeof(Head.Name) - 1;
 114          for (; Head.Name[I] == ' ' || Head.Name[I] == '/'; I--);
 115          Memb->Name = string(Head.Name,I+1);
 116       }
 117
 118       // Account for the AR header alignment
 119       unsigned Skip = Memb->Size % 2;
 120
 121       // Add it to the list
 122       Memb->Next = List;
 123       List = Memb;
 124       Memb->Start = File.Tell();
 125       if (File.Skip(Memb->Size + Skip) == false)
 126          return false;
 127       if (Left < (signed)(Memb->Size + Skip))
 128          return _error->Error(_("Archive is too short"));
 129       Left -= Memb->Size + Skip;
 130    }
 131    if (Left != 0)
 132       return _error->Error(_("Failed to read the archive headers"));
 133
 134    return true;
 135 }
 136                                                                         /*}}}*/
 137 // ARArchive::FindMember - Find a name in the member list               /*{{{*/
 138 // ---------------------------------------------------------------------
 139 /* Find a member with the given name */
 140 const ARArchive::Member *ARArchive::FindMember(const char *Name) const
 141 {
 142    const Member *Res = List;
 143    while (Res != 0)
 144    {
 145       if (Res->Name == Name)
 146          return Res;
 147       Res = Res->Next;
 148    }
 149
 150    return 0;
 151 }
 152                                                                         /*}}}*/