Class: Gdbdump::GDB

Inherits:
Object
  • Object
show all
Defined in:
lib/gdbdump/gdb.rb

Overview

GDB.new(pid: 999, debug: true).run do |gdb|

puts gdb.cmd_exec('bt')

end

Constant Summary collapse

COMMAND_READ_BUFFER_SIZE = 
1024
SUDO_CMD = 
'sudo'

Instance Method Summary collapse

Constructor Details

#initialize(ruby: nil, pid_or_core:, debug: false, gdbinit: nil, gdb: nil) ⇒ GDB

Returns a new instance of GDB.



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# File 'lib/gdbdump/gdb.rb', line 12

def initialize(ruby: nil, pid_or_core:, debug: false, gdbinit: nil, gdb: nil)
  if pid_or_core =~ /\A\d+\z/
    @pid  = pid_or_core.to_s
    @ruby = ruby || Procfs.new(@pid).exe
  else
    @core = pid_or_core
    raise "core #{@core} is not readable" unless File.readable?(@core)
    @ruby = ruby || raise("With core file, ruby path is required")
  end
  @pid_or_core = pid_or_core
  raise "ruby #{@ruby} is not accessible" unless File.executable?(@ruby)

  @gdbinit = gdbinit || File.join(ROOT, 'vendor', 'ruby', ruby_minor_version, 'gdbinit')
  raise "gdbinit #{@gdbinit} is not readable" unless File.readable?(@gdbinit)

  @debug = debug
  @gdb = gdb || 'gdb'

  @exec_options = [@gdb, '-silent', '-nw', '-x', @gdbinit, @ruby, @pid_or_core]
  @exec_options.unshift(SUDO_CMD) if @pid # sudo is required to ptrace a living process
  log('C', @exec_options.join(' '))
end

Instance Method Details

#cmd_exec(cmd) ⇒ Object 



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# File 'lib/gdbdump/gdb.rb', line 68

def cmd_exec(cmd)
  log('C', cmd)
  if cmd
    send_cmd = cmd.empty? ? cmd : "#{cmd}\n"
    r = @stdin.syswrite(send_cmd)
    raise "failed to send: [#{cmd}]" if r < send_cmd.length
  end

  get_response
end

#get_response ⇒ Object 



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# File 'lib/gdbdump/gdb.rb', line 79

def get_response
  out = +''
  loop do
    begin
      buf = @stdout.sysread(COMMAND_READ_BUFFER_SIZE)
    rescue EOFError
      break
    end
    break if buf =~ /\(gdb\) $/
    out << buf
  end
  log('O', out)

  err = +''
  loop do
    begin
      buf = @stderr.read_nonblock(COMMAND_READ_BUFFER_SIZE)
    rescue Errno::EAGAIN, Errno::EWOULDBLOCK
      break
    rescue EOFError
      break
    end
    err << buf if buf
  end
  log('E', err)

  [out, err]
end

#print_backtrace ⇒ Object 



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# File 'lib/gdbdump/gdb.rb', line 43

def print_backtrace
  run do |gdb|
    out, err = gdb.cmd_exec('rb_ps')
    $stdout.puts out
    $stderr.puts err unless err.empty?
  end
end

#run ⇒ Object 



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# File 'lib/gdbdump/gdb.rb', line 51

def run
  @stdin, @stdout, @stderr = Open3.popen3(*@exec_options)
  if get_response =~ /ptrace: Operation not permitted/
    raise 'root privilege is required'
  end
  prepare
  begin
    yield(self)
    detach
  ensure
    Process.kill('CONT', @pid.to_i) if @pid
    @stdin.close
    @stdout.close
    @stderr.close
  end
end