应用错误收集

我能够使其工作的唯一方法是修改核心文件本身，以获得包含新数据的附加程序头/部分。

从理论上讲，我相信objcopy应该能够做到这一点，但经过大量的测试后，我无法让它发挥作用。相反，我使用编写修改核心文件的perl脚本。

以下是那些陷入类似情况的人的脚本（注意这是针对i386拱门上的ELF核心文件）：

#!/usr/bin/perl

my @elfHeader = (
  [ident => 'A16'],
  [e_type => 'v'],
  [e_machine => 'v'],
  [e_version => 'V'],
  [e_entry => 'V'],
  [e_phoff => 'V'],
  [e_shoff => 'V'],
  [e_flags => 'V'],
  [e_ehsize => 'v'],
  [e_phentsize => 'v'],
  [e_phnum => 'v'],
  [e_shentsize => 'v'],
  [e_shnum => 'v'],
  [e_shstrndx => 'v']
);

my @progHeader = (
  [ptype => 'V'],
  [poffset => 'V'],
  [pvaddr => 'V'],
  [ppaddr => 'V'],
  [pfilesz => 'V'],
  [pmemsz => 'V'],
  [pflags => 'V'],
  [palign => 'V'],
);


my ($core, $dataFile, $outFile) = @ARGV;

main();


sub main {

  my @stat = stat($core);
  my $coreSize = $stat[7];

  @stat = stat($dataFile);
  my $dfSize = $stat[7];

  my ($in, $out, $df);
  open($in, "", $outFile) || die("Couldn't open $outFile: $!");

  my $buf;
  my $bytes = sysread($in, $buf, 52);

  my $hdr = unpackStruct(\@elfHeader, $buf);

  # Fix the elf header to have an additional program header
  my $phNum = $hdr->{e_phnum};
  $hdr->{e_phnum}++;

  # Fix the header to point to a new location for the program headers (at the end of the file)
  my $phOff = $hdr->{e_phoff};
  $hdr->{e_phoff} = $coreSize;

  # Read in the full program header table
  my $phTable;
  sysseek($in, $phOff, 0);
  my $readSize = $hdr->{e_phentsize} * $phNum;
  $bytes = sysread($in, $phTable, $readSize);

  # Add an additional entry to the end of the ph table
  my $entry = packStruct(\@progHeader, {ptype => 1, 
                                        poffset => $coreSize + $hdr->{e_phentsize} * $hdr->{e_phnum},
                                        pvaddr => 0x80f95000,
                                        ppaddr => 0,
                                        pfilesz => $dfSize,
                                        pmemsz => $dfSize,
                                        pflags => 7,
                                        palign => 4096});

  $phTable .= $entry;

  # Form the new elf header
  my $elf = packStruct(\@elfHeader, $hdr);

  # Output the new header
  syswrite($out, $elf, length($elf));

  # Copy the full core file after the header
  sysseek($in, 52, 0);
  copyData($in, $out, $coreSize - 52);

  # Output the new program table
  syswrite($out, $phTable, length($phTable));

  # Add the data on the end
  copyData($df, $out, $dfSize);

}


sub copyData {
  my ($in, $out, $numBytes) = @_;

  my $buf;

  while ($numBytes > 0) {
    my $readBytes = sysread($in, $buf, 8192);
    syswrite($out, $buf, $readBytes);
    $numBytes -= $readBytes;
  }

}


sub unpackStruct {
  my ($fields, $data) = @_;

  my $unpack;
  map {$unpack .= $_->[1]} @{$fields};

  my @vals = unpack($unpack, $data);

  my %res;
  foreach my $field (@{$fields}) {
    $res{$field->[0]} = shift(@vals);
  }

  return \%res;

}


sub packStruct {
  my ($fields, $data) = @_;

  my $pack;
  map {$pack .= $_->[1]} @{$fields};

  my @vals;
  foreach my $field (@{$fields}) {
    push(@vals, $data->{$field->[0]})
  }

  my $res = pack($pack, @vals);

  return $res;

}

据我所知，gdb可以在核心文件或正在运行的进程上运行。您似乎要描述的是混合：运行核心文件。我不认为这是可能的，gdb documentation表明没有其他选择。

当GDB调试核心文件时，是否可以将充满二进制数据的文件加载到GDB中？

3 个答案: