gdb7 hooks for MRI
  (c) 2009 Aman Gupta (tmm1)

=== Requirements

  gdb.rb currently requires x86_64 linux, and MRI/REE 1.8.x or 1.9.2.

=== Usage

  $ ps aux | grep deploy.rb
  13074  0.0  0.7  90164 31720 ?        R    Sep23   2:21 /usr/bin/ruby /usr/bin/god -c deploy.rb

  $ sudo gdb.rb 13074
  GNU gdb (GDB) 7.0
  Reading symbols from /usr/bin/ruby...done.
  Attaching to program: /usr/bin/ruby, process 13074
  0x00007fa8b9cb3c93 in select () from /lib/libc.so.6

  (gdb) ruby eval 1+2
  2

  (gdb) ruby eval Thread.list.count
  17

  (gdb) ruby threads list
  0x1589000 main      thread  THREAD_STOPPED   WAIT_JOIN(0x19ef400)           4417 bytes
  0x19ef400           thread  THREAD_STOPPED   WAIT_TIME(57.10)               6267 bytes
  0x19e3400           thread  THREAD_STOPPED   WAIT_FD(5)                    10405 bytes
  0x19e0000           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19e0400           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19e0800           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19e0c00           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19de000           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19de400           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19de800           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19dec00           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19dc000           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19dc400           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19dc800           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x19dcc00           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x2266800           thread  THREAD_STOPPED   WAIT_NONE                     14237 bytes
  0x1d63000      curr thread  THREAD_RUNNABLE  WAIT_NONE

  (gdb) ruby threads
  0x1589000 main      thread  THREAD_STOPPED   WAIT_JOIN(0x19ef400)           4417 bytes
         node_call      join in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:626
         node_call      start in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:633
         node_call      at_exit in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:666
         node_fcall     (unknown) in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/cli/run.rb:87

  0x19ef400           thread  THREAD_STOPPED   WAIT_TIME(45.25)               6267 bytes
         node_fcall     sleep in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:622
         node_fcall     start in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:621
         node_fcall     loop in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:621
         node_call      start in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:620
         node_call      initialize in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:620
         node_call      new in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:620
         node_call      start in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:633
         node_call      at_exit in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god.rb:666
         node_fcall     (unknown) in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/cli/run.rb:87

  0x19e3400           thread  THREAD_STOPPED   WAIT_FD(5)                    10405 bytes
         node_call      accept in /usr/lib/ruby/1.8/drb/unix.rb:98
         node_call      accept in /usr/lib/ruby/1.8/drb/drb.rb:1581
         node_vcall     main_loop in /usr/lib/ruby/1.8/drb/drb.rb:1430
         node_call      run in /usr/lib/ruby/1.8/drb/drb.rb:1427
         node_call      start in /usr/lib/ruby/1.8/drb/drb.rb:1427
         node_vcall     run in /usr/lib/ruby/1.8/drb/drb.rb:1347
         node_call      initialize in /usr/lib/ruby/1.8/drb/drb.rb:1627

  (gdb) ruby threads trace
  -- Tracing thread context switches.
  0x19ef400           thread  THREAD_RUNNABLE  WAIT_NONE                      6267 bytes
  0x1d63000           thread  THREAD_RUNNABLE  WAIT_NONE                      8623 bytes
  0x19e3400           thread  THREAD_RUNNABLE  WAIT_NONE                     10405 bytes
  0x3001c00           thread  THREAD_RUNNABLE  WAIT_NONE                      9507 bytes
  0x19e3400           thread  THREAD_RUNNABLE  WAIT_NONE                      9507 bytes
  0x3001c00           thread  THREAD_RUNNABLE  WAIT_NONE                     15059 bytes
  0x1d63000           thread  THREAD_RUNNABLE  WAIT_NONE                      8623 bytes
  0x3001c00           thread  THREAD_RUNNABLE  WAIT_NONE                     15059 bytes

  (gdb) ruby trace 25
  -- Tracing the next 25 ruby method calls.
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  watching_pid? in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:58
  [] in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:59
  default in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:59
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  watching_pid? in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:58
  [] in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:59
  default in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:59
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  watching_pid? in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:58
  [] in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:59
  default in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:59
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66
  watching_pid? in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:58
  [] in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:59
  default in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:59
  handle_events in /usr/lib/ruby/gems/1.8/gems/god-0.7.13/bin/../lib/god/event_handler.rb:66

  (gdb) ruby objects

    HEAPS            8
    SLOTS      1686252
    LIVE        893327 (52.98%)
    FREE        792925 (47.02%)

    bignum           2 (0.00%)
    file            51 (0.01%)
    float           77 (0.01%)
    module         781 (0.09%)
    varmap        1354 (0.15%)
    scope         1641 (0.18%)
    match         1676 (0.19%)
    iclass        1744 (0.20%)
    regexp        2255 (0.25%)
    data          3539 (0.40%)
    class         3680 (0.41%)
    hash          6196 (0.69%)
    object        8785 (0.98%)
    array        13850 (1.55%)
    string      105350 (11.79%)
    node        742346 (83.10%)

  (gdb) ruby objects classes
         1 YAML::Syck::Resolver
         1 YAML::Syck::Resolver
         1 SystemStackError
         1 Object
         1 Object
         1 NoMemoryError
         1 fatal
         1 Object
         1 Gem::SourceIndex
         1 Gem::GemPathSearcher
         1 Gem::ConfigFile
         1 God::Logger
         1 God::SimpleLogger
         1 God::CLI::Run
         1 DRb::DRbServer::InvokeMethod
         1 DRb::DRbServer
         1 DRb::DRbIdConv
         1 God::Registry
         1 OptionParser::Switch::OptionalArgument
         1 OptionParser
         1 God::Socket
         1 God::Contacts::Email
         2 Date::Infinity
         2 DRb::DRbMessage
         2 DRb::DRbBadScheme
         2 DRb::DRbUNIXSocket
         3 OptionParser::List
         6 IOError
         6 Errno::ESRCH
         6 OptionParser::Switch::RequiredArgument
         6 Net::InternetMessageIO
         7 God::System::SlashProcPoller
         7 God::System::Process
         7 God::DriverOperation
         7 Net::SMTP
         8 StandardError
        10 OptionParser::Switch::NoArgument
        13 God::Conditions::Flapping
        13 God::Conditions::ProcessExits
        13 God::Behaviors::CleanPidFile
        13 God::Process
        13 God::Watch
        13 God::Driver
        13 God::DriverEventQueue
        19 God::DriverEvent
        38 Process::Status
        39 God::Conditions::ProcessRunning
        50 Range
        63 Gem::Specification
        65 God::Metric
        81 Gem::Dependency
       174 Gem::Version::Part
       209 Gem::Requirement
       219 Gem::Version

  (gdb) ruby objects strings 
         70 u'bin'
         73 u' INFO'
         74 u'--main'
         74 u'I'
         75 u'..'
         78 u'ruby'
         80 u'::'
         92 u'1.3.2'
        100 u'README.rdoc'
        102 u' '
        108 u'Rakefile'
        110 u'README'
        114 u'\r\n'
        127 u'>='
        140 u'lib'
        158 u'0'
        294 u'\n'
        619 u''

      30503 unique strings
    3187435 bytes

  (gdb) ruby objects nodes 
      8156 NODE_EVSTR
      8966 NODE_COLON2
     10020 NODE_DVAR
     11493 NODE_AND
     13157 NODE_FCALL
     14493 NODE_VCALL
     15148 NODE_ARGS
     15180 NODE_CONST
     15445 NODE_SCOPE
     16582 NODE_IF
     21594 NODE_LASGN
     22084 NODE_METHOD
     26633 NODE_STR
     37819 NODE_LIT
     64325 NODE_LVAR
     64470 NODE_NEWLINE
     69436 NODE_BLOCK
     85825 NODE_CALL
    126739 NODE_ARRAY


=== TODO

  `ruby where` for the current stack trace
  `ruby print` to inspect ruby variables
  `ruby breakpoint` to breakpoint on ruby methods
  `ruby irb` for a simple interactive shell


=== Credits

  Tom Tromey for his work on gdb python support (gdb-eval.patch, gdb-breakpoints.patch) and help
  tracking down some memory leaks (gdb-leak.patch)

  Joe Damato for writing parts of ruby-gdb.py and various gdb hacks to make gdb.rb possible.


=== License

  Available under the Ruby License.