#!/usr/bin/env ruby

# usage: redirect-process pid output

require 'tempfile'

pid = ARGV.shift.to_i
output = ARGV.shift

f = open(output, 'w')

t = Tempfile.new("redirect-process.gdb")
t.puts <<"End"
attach #{pid}
print dup2(open("/proc/#{$$}/fd/#{f.fileno}", #{File::WRONLY}), #{STDOUT.fileno})
End
t.close

# shut up gdb.
STDOUT.reopen("/dev/null")
STDERR.reopen("/dev/null")

system("gdb", "-batch", "-n", "-x", t.path)