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<config.h>
  18
  19 #include <apt-pkg/arfile.h>
  20 #include <apt-pkg/strutl.h>
  21 #include <apt-pkg/fileutl.h>
  22 #include <apt-pkg/error.h>
  23
  24 #include <stdlib.h>
  25
  26 #include <apti18n.h>
  27                                                                         /*}}}*/
  28
  29 struct ARArchive::MemberHeader
  30 {
  31    char Name[16];
  32    char MTime[12];
  33    char UID[6];
  34    char GID[6];
  35    char Mode[8];
  36    char Size[10];
  37    char Magic[2];
  38 };
  39
  40 // ARArchive::ARArchive - Constructor                                   /*{{{*/
  41 // ---------------------------------------------------------------------
  42 /* */
  43 ARArchive::ARArchive(FileFd &File) : List(0), File(File)
  44 {
  45    LoadHeaders();
  46 }
  47                                                                         /*}}}*/
  48 // ARArchive::~ARArchive - Destructor                                   /*{{{*/
  49 // ---------------------------------------------------------------------
  50 /* */
  51 ARArchive::~ARArchive()
  52 {
  53    while (List != 0)
  54    {
  55       Member *Tmp = List;
  56       List = List->Next;
  57       delete Tmp;
  58    }
  59 }
  60                                                                         /*}}}*/
  61 // ARArchive::LoadHeaders - Load the headers from each file             /*{{{*/
  62 // ---------------------------------------------------------------------
  63 /* AR files are structured with a 8 byte magic string followed by a 60
  64    byte plain text header then the file data, another header, data, etc */
  65 bool ARArchive::LoadHeaders()
  66 {
  67    off_t Left = File.Size();
  68
  69    // Check the magic byte
  70    char Magic[8];
  71    if (File.Read(Magic,sizeof(Magic)) == false)
  72       return false;
  73    if (memcmp(Magic,"!<arch>\012",sizeof(Magic)) != 0)
  74       return _error->Error(_("Invalid archive signature"));
  75    Left -= sizeof(Magic);
  76
  77    // Read the member list
  78    while (Left > 0)
  79    {
  80       MemberHeader Head;
  81       if (File.Read(&Head,sizeof(Head)) == false)
  82          return _error->Error(_("Error reading archive member header"));
  83       Left -= sizeof(Head);
  84
  85       // Convert all of the integer members
  86       Member *Memb = new Member();
  87       if (StrToNum(Head.MTime,Memb->MTime,sizeof(Head.MTime)) == false ||
  88           StrToNum(Head.UID,Memb->UID,sizeof(Head.UID)) == false ||
  89           StrToNum(Head.GID,Memb->GID,sizeof(Head.GID)) == false ||
  90           StrToNum(Head.Mode,Memb->Mode,sizeof(Head.Mode),8) == false ||
  91           StrToNum(Head.Size,Memb->Size,sizeof(Head.Size)) == false)
  92       {
  93          delete Memb;
  94          return _error->Error(_("Invalid archive member header %s"), Head.Name);
  95       }
  96
  97       // Check for an extra long name string
  98       if (memcmp(Head.Name,"#1/",3) == 0)
  99       {
 100          char S[300];
 101          unsigned long Len;
 102          if (StrToNum(Head.Name+3,Len,sizeof(Head.Size)-3) == false ||
 103              Len >= sizeof(S))
 104          {
 105             delete Memb;
 106             return _error->Error(_("Invalid archive member header"));
 107          }
 108          if (File.Read(S,Len) == false)
 109          {
 110             delete Memb;
 111             return false;
 112          }
 113          S[Len] = 0;
 114          Memb->Name = S;
 115          Memb->Size -= Len;
 116          Left -= Len;
 117       }
 118       else
 119       {
 120          unsigned int I = sizeof(Head.Name) - 1;
 121          for (; Head.Name[I] == ' ' || Head.Name[I] == '/'; I--);
 122          Memb->Name = std::string(Head.Name,I+1);
 123       }
 124
 125       // Account for the AR header alignment
 126       off_t Skip = Memb->Size % 2;
 127
 128       // Add it to the list
 129       Memb->Next = List;
 130       List = Memb;
 131       Memb->Start = File.Tell();
 132       if (File.Skip(Memb->Size + Skip) == false)
 133          return false;
 134       if (Left < (off_t)(Memb->Size + Skip))
 135          return _error->Error(_("Archive is too short"));
 136       Left -= Memb->Size + Skip;
 137    }
 138    if (Left != 0)
 139       return _error->Error(_("Failed to read the archive headers"));
 140
 141    return true;
 142 }
 143                                                                         /*}}}*/
 144 // ARArchive::FindMember - Find a name in the member list               /*{{{*/
 145 // ---------------------------------------------------------------------
 146 /* Find a member with the given name */
 147 const ARArchive::Member *ARArchive::FindMember(const char *Name) const
 148 {
 149    const Member *Res = List;
 150    while (Res != 0)
 151    {
 152       if (Res->Name == Name)
 153          return Res;
 154       Res = Res->Next;
 155    }
 156
 157    return 0;
 158 }
 159                                                                         /*}}}*/