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 boundary.
  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 <string.h>
  25 #include <sys/types.h>
  26 #include <string>
  27
  28 #include <apti18n.h>
  29                                                                         /*}}}*/
  30
  31 struct ARArchive::MemberHeader
  32 {
  33    char Name[16];
  34    char MTime[12];
  35    char UID[6];
  36    char GID[6];
  37    char Mode[8];
  38    char Size[10];
  39    char Magic[2];
  40 };
  41
  42 // ARArchive::ARArchive - Constructor                                   /*{{{*/
  43 // ---------------------------------------------------------------------
  44 /* */
  45 ARArchive::ARArchive(FileFd &File) : List(0), File(File)
  46 {
  47    LoadHeaders();
  48 }
  49                                                                         /*}}}*/
  50 // ARArchive::~ARArchive - Destructor                                   /*{{{*/
  51 // ---------------------------------------------------------------------
  52 /* */
  53 ARArchive::~ARArchive()
  54 {
  55    while (List != 0)
  56    {
  57       Member *Tmp = List;
  58       List = List->Next;
  59       delete Tmp;
  60    }
  61 }
  62                                                                         /*}}}*/
  63 // ARArchive::LoadHeaders - Load the headers from each file             /*{{{*/
  64 // ---------------------------------------------------------------------
  65 /* AR files are structured with a 8 byte magic string followed by a 60
  66    byte plain text header then the file data, another header, data, etc */
  67 bool ARArchive::LoadHeaders()
  68 {
  69    off_t Left = File.Size();
  70
  71    // Check the magic byte
  72    char Magic[8];
  73    if (File.Read(Magic,sizeof(Magic)) == false)
  74       return false;
  75    if (memcmp(Magic,"!<arch>\012",sizeof(Magic)) != 0)
  76       return _error->Error(_("Invalid archive signature"));
  77    Left -= sizeof(Magic);
  78
  79    // Read the member list
  80    while (Left > 0)
  81    {
  82       MemberHeader Head;
  83       if (File.Read(&Head,sizeof(Head)) == false)
  84          return _error->Error(_("Error reading archive member header"));
  85       Left -= sizeof(Head);
  86
  87       // Convert all of the integer members
  88       Member *Memb = new Member();
  89       if (StrToNum(Head.MTime,Memb->MTime,sizeof(Head.MTime)) == false ||
  90           StrToNum(Head.UID,Memb->UID,sizeof(Head.UID)) == false ||
  91           StrToNum(Head.GID,Memb->GID,sizeof(Head.GID)) == false ||
  92           StrToNum(Head.Mode,Memb->Mode,sizeof(Head.Mode),8) == false ||
  93           StrToNum(Head.Size,Memb->Size,sizeof(Head.Size)) == false)
  94       {
  95          delete Memb;
  96          return _error->Error(_("Invalid archive member header %s"), Head.Name);
  97       }
  98
  99       // Check for an extra long name string
 100       if (memcmp(Head.Name,"#1/",3) == 0)
 101       {
 102          char S[300];
 103          unsigned long Len;
 104          if (StrToNum(Head.Name+3,Len,sizeof(Head.Size)-3) == false ||
 105              Len >= sizeof(S))
 106          {
 107             delete Memb;
 108             return _error->Error(_("Invalid archive member header"));
 109          }
 110          if (File.Read(S,Len) == false)
 111          {
 112             delete Memb;
 113             return false;
 114          }
 115          S[Len] = 0;
 116          Memb->Name = S;
 117          Memb->Size -= Len;
 118          Left -= Len;
 119       }
 120       else
 121       {
 122          unsigned int I = sizeof(Head.Name) - 1;
 123          for (; Head.Name[I] == ' ' || Head.Name[I] == '/'; I--);
 124          Memb->Name = std::string(Head.Name,I+1);
 125       }
 126
 127       // Account for the AR header alignment
 128       off_t Skip = Memb->Size % 2;
 129
 130       // Add it to the list
 131       Memb->Next = List;
 132       List = Memb;
 133       Memb->Start = File.Tell();
 134       if (File.Skip(Memb->Size + Skip) == false)
 135          return false;
 136       if (Left < (off_t)(Memb->Size + Skip))
 137          return _error->Error(_("Archive is too short"));
 138       Left -= Memb->Size + Skip;
 139    }
 140    if (Left != 0)
 141       return _error->Error(_("Failed to read the archive headers"));
 142
 143    return true;
 144 }
 145                                                                         /*}}}*/
 146 // ARArchive::FindMember - Find a name in the member list               /*{{{*/
 147 // ---------------------------------------------------------------------
 148 /* Find a member with the given name */
 149 const ARArchive::Member *ARArchive::FindMember(const char *Name) const
 150 {
 151    const Member *Res = List;
 152    while (Res != 0)
 153    {
 154       if (Res->Name == Name)
 155          return Res;
 156       Res = Res->Next;
 157    }
 158
 159    return 0;
 160 }
 161                                                                         /*}}}*/