+# This file is part of chiark-utils, a collection of useful programs
+# used on chiark.greenend.org.uk.
+#
+# This file is:
+# Copyright 2018 Citrix Systems Ltd
+#
+# This is free software; you can redistribute it and/or modify it under the
+# terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 3, or (at your option) any later version.
+#
+# This is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, consult the Free Software Foundation's
+# website at www.fsf.org, or the GNU Project website at www.gnu.org.
+
# class for use inside gdb which is debugging the donor process
+from __future__ import print_function
+
import gdb
import copy
import os
def _lit_array(elemtype, val_lit_strs):
return (
'((%s[%d])%s)' %
- (elem_type, len(val_lit_strs), _lit_aggregate_uncasted(val_lit_strs))
+ (elemtype, len(val_lit_strs), _lit_aggregate_uncasted(val_lit_strs))
)
def _lit_addressof(v):
- return '&(%s)' % v
+ return '&(char[])(%s)' % v
def _make_lit(v):
if isinstance(v, int):
class DonorStructLayout():
def __init__(l, typename):
- x = parse_eval('(%s){ }' % typename)
+ x = gdb.lookup_type(typename)
l._typename = typename
l._template = [ ]
l._posns = { }
- for f in x.type.fields():
+ for f in x.fields():
l._posns[f.name] = len(l._template)
try: f.type.fields(); blank = '{ }'
except TypeError: blank = '0'
di._structs = { }
di._saved_errno = None
di._result_stream = os.fdopen(3, 'w')
+ di._errno_workaround = None
# assembling structs
# sigh, we have to record the order of the arguments!
fields = di._find_fields(typename)
return fields.substitute(values)
+ # hideous workaround
+
+ def _parse_eval_errno(di, expr_pat):
+ # evaluates expr_pat % 'errno'
+ if di._errno_workaround is not True:
+ try:
+ x = parse_eval(expr_pat % 'errno')
+ di._errno_workaround = False
+ return x
+ except gdb.error as e:
+ if di._errno_workaround is False:
+ raise e
+ di._errno_workaround = True
+ # Incomprehensibly, gdb.parse_and_eval('errno') can sometimes
+ # fail with
+ # gdb.error: Cannot find thread-local variables on this target
+ # even though plain gdb `print errno' works while `print errno = 25'
+ # doesn't. OMG. This may be related to:
+ # https://github.com/cloudburst/libheap/issues/24
+ # although I can't find it in the gdb bug db (which is half-broken
+ # in my browser). Also the error is very nonspecific :-/.
+ # This seems to happen on jessie, and is fixed in stretch.
+ # Anyway:
+ return parse_eval(expr_pat % '(*((int (*)(void))__errno_location)())')
+
# calling functions (need to cast the function name to the right
# type in case maybe gdb doesn't know the type)
def _must_func(di, functype, funcname, realargs):
retval = di._func(functype, funcname, realargs)
if retval < 0:
- errnoval = parse_eval('errno')
+ errnoval = di._parse_eval_errno('%s')
raise RuntimeError("%s gave errno=%d `%s'" %
(funcname, errnoval, os.strerror(errnoval)))
return retval
# wrappers for the syscalls that do what we want
def _sendmsg(di, carrier, control_msg):
- iov_base = _lit_array('int', [str(x) for x in fds])
+ iov_base = _lit_array('char', [1])
iov = di._make('struct iovec', {
'iov_base': iov_base,
- 'iov_len' : len(fds),
+ 'iov_len' : 1,
})
msg = di._make('struct msghdr', {
})
di._must_func(
- 'ssize_t (*)(int, const struct msghdr*, int flags)',
+ 'ssize_t (*)(int, const struct msghdr*, int)',
'sendmsg',
'(%s, %s, 0)' % (carrier, _lit_addressof(msg))
)
'("%s", %d)' % (_string_escape_for_c(path), mode)
)
if r < 0:
- errnoval = parse_eval('errno')
+ errnoval = di._parse_eval_errno('%s')
if errnoval != os.errno.EEXIST:
raise RuntimeError("mkdir %s failed: `%s'" %
(repr(path), os.strerror(errnoval)))
return 1
def _errno_save(di):
- di._saved_errno = parse_eval('errno')
+ di._saved_errno = di._parse_eval_errno('%s')
def _errno_restore(di):
to_restore = di._saved_errno
di._saved_errno = None
if to_restore is not None:
- parse_eval('errno = %d' % to_restore)
+ di._parse_eval_errno('%%s = %d' % to_restore)
def _result(di, output):
sys.stderr.write("#> %s" % output)
di._result('%d\n' % val)
def _protocol_read(di):
- input = sys.stdin.readline().rstrip('\n')
+ input = sys.stdin.readline()
+ if input == '': return None
+ input = input.rstrip('\n')
sys.stderr.write("#< %s\n" % input)
return input
def eval_loop(di):
+ if not gdb.selected_inferior().was_attached:
+ print('gdb inferior not attached', file=sys.stderr)
+ sys.exit(0)
while True:
di._result('!\n')
cmd = di._protocol_read()
+ if cmd is None: break
eval(cmd)
~ian / chiark-utils.git / blobdiff