Show source files and line numers of given process's threads

pid2line.rb

#!/usr/bin/env ruby
#
# pid2line.rb
#
# Show source files and line numers of given process's threads
#
# This script works only on Linux.
# https://gist.github.com/nurse/0619b6af90df140508c2
#

# Get the current EIP of threads in the given process
# see kstkeip of http://man7.org/linux/man-pages/man5/proc.5.html
def get_eips(pid)
  Dir["/proc/#{pid}/task/*/stat"].map do |path|
    lwpid = path[/task\/(\d+)/, 1].to_i
    stat = `sudo cat #{path}`
    name = stat[/\((.*)\)/, 1]
    ary = $'.split
    state = ary[0]
    eip = ary[27].to_i
    utime = ary[11].to_i
    [lwpid, eip, name, state, utime]
  end
end

# Get [executable or library path, relative_address]
def search_maps(lwpid, eip)
  `sudo cat /proc/#{lwpid}/maps`.each_line do |line|
    address, perms, offset, dev, inode, pathname = line.split
    range = Range.new(*address.split('-').map{|x|x.hex})
    if range.include?(eip)
      reladdr = eip - range.first
      return [pathname, offset, reladdr]
    end
  end
end

# get an address in an executable or a library
def get_addr(path, offset, reladdr)
  abort unless / LOAD +(0x\w+) +(0x\w+)/ =~ `readelf -Wl #{path}`
  abort unless $1.to_i != offset
  vaddr = reladdr + Integer($2)
  puts "Elf vaddr: %x -> %x in %s" % [reladdr, vaddr, path]
  vaddr
end

# http://man7.org/linux/man-pages/man1/addr2line.1.html
def addr2line(path, addr)
  system('addr2line', '-fie', path, addr.to_s(16))
end

def main
  unless pid = ARGV.shift
    puts "#$0: <pid>"
  end

  addrs = get_eips(pid)
  addrs.each do |lwpid, eip, name, state, utime|
    path, offset, reladdr = search_maps(lwpid, eip)
    puts "%-15s state:%s utime:%d LWPID:%d EIP:%x -> %x" % [name, state, utime, lwpid, eip, reladdr]
    addr = get_addr(path, offset, reladdr)
    addr2line(path, addr)
  end
end

main