scripts/qemugdb/aio.py

   1 #
   2 # GDB debugging support: aio/iohandler debug
   3 #
   4 # Copyright (c) 2015 Red Hat, Inc.
   5 #
   6 # Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
   7 #
   8 # This work is licensed under the terms of the GNU GPL, version 2 or
   9 # later.  See the COPYING file in the top-level directory.
  10 #
  11
  12 import gdb
  13 from qemugdb import coroutine
  14
  15 def isnull(ptr):
  16     return ptr == gdb.Value(0).cast(ptr.type)
  17
  18 def dump_aiocontext(context, verbose):
  19     '''Display a dump and backtrace for an aiocontext'''
  20     cur = context['aio_handlers']['lh_first']
  21     # Get pointers to functions we're going to process specially
  22     sym_fd_coroutine_enter = gdb.parse_and_eval('fd_coroutine_enter')
  23
  24     while not isnull(cur):
  25         entry = cur.dereference()
  26         gdb.write('----\n%s\n' % entry)
  27         if verbose and cur['io_read'] == sym_fd_coroutine_enter:
  28             coptr = (cur['opaque'].cast(gdb.lookup_type('FDYieldUntilData').pointer()))['co']
  29             coptr = coptr.cast(gdb.lookup_type('CoroutineUContext').pointer())
  30             coroutine.bt_jmpbuf(coptr['env']['__jmpbuf'])
  31         cur = cur['node']['le_next'];
  32
  33     gdb.write('----\n')
  34
  35 class HandlersCommand(gdb.Command):
  36     '''Display aio handlers'''
  37     def __init__(self):
  38         gdb.Command.__init__(self, 'qemu handlers', gdb.COMMAND_DATA,
  39                              gdb.COMPLETE_NONE)
  40
  41     def invoke(self, arg, from_tty):
  42         verbose = False
  43         argv = gdb.string_to_argv(arg)
  44
  45         if len(argv) > 0 and argv[0] == '--verbose':
  46             verbose = True
  47             argv.pop(0)
  48
  49         if len(argv) > 1:
  50             gdb.write('usage: qemu handlers [--verbose] [handler]\n')
  51             return
  52
  53         if len(argv) == 1:
  54             handlers_name = argv[0]
  55         else:
  56             handlers_name = 'qemu_aio_context'
  57         dump_aiocontext(gdb.parse_and_eval(handlers_name), verbose)