X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=chiark-utils.git;a=blobdiff_plain;f=fishdescriptor%2Fpy%2Ffishdescriptor%2Findonor.py;h=f701434540d9d56b88237228e1fb195e88c4d54a;hp=1f3c68994feabe4715f89b8de51dfc7ffe15cd14;hb=33545a21597767a50443a717b015fc9e3c8dd553;hpb=d8d60f17dad9d2e9a01729d9f21b0a99f1aeb4ce diff --git a/fishdescriptor/py/fishdescriptor/indonor.py b/fishdescriptor/py/fishdescriptor/indonor.py index 1f3c689..f701434 100644 --- a/fishdescriptor/py/fishdescriptor/indonor.py +++ b/fishdescriptor/py/fishdescriptor/indonor.py @@ -4,10 +4,19 @@ import gdb import copy import os +import sys +import socket +import re + +def _string_bytearray(s): + # gets us bytes in py2 and py3 + if not isinstance(s, bytes): + s = s.encode('utf-8') # sigh, python 2/3 compat + return bytearray(s) def _string_escape_for_c(s): out = '' - for c in bytearray(s): # gets us bytes in py2 and py3 + for c in _string_bytearray(s): if c == ord('\\') or c == ord('"') or c < 32 or c > 126: out += '\\x%02x' % c else: @@ -23,19 +32,17 @@ def _lit_aggregate_uncasted(val_lit_strs): return '{' + ', '.join(['(%s)' % v for v in val_lit_strs]) + ' }' def _lit_string_uncasted(s): - if not isinstance(s, bytes): - s = s.encode('utf-8') # sigh, python 2/3 compat - b = bytearray(s) - return _lit_aggregate_uncasted(map(_lit_integer, b) + [ '0' ]) + b = _string_bytearray(s) + return _lit_aggregate_uncasted([_lit_integer(x) for x in b] + [ '0' ]) 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): @@ -43,17 +50,37 @@ def _make_lit(v): else: return v # should already be an integer +def parse_eval(expr): + sys.stderr.write("## EVAL %s\n" % repr(expr)) + x = gdb.parse_and_eval(expr) + sys.stderr.write('## => %s\n' % x) + sys.stderr.flush() + return x + +def parse_eval_via_print(expr): + # works only with things whose value is an int and where expr is simple + sys.stderr.write("## EVAL-VIA-PRINT %s\n" % repr(expr)) + x = gdb.execute('print %s' % expr, to_string=True) + m = re.match('\$\d+ = (\d+)\n$', x) # seriously ! + r = int(m.group(1)) + sys.stderr.write('## => %s\n' % r) + return 4 + class DonorStructLayout(): def __init__(l, typename): - x = gdb.parse_and_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 = '{ }' + try: f.type.fields(); blank = '{ }' + except TypeError: blank = '0' except AttributeError: blank = '0' l._template.append(blank) + sys.stderr.write('## STRUCT %s template %s fields %s\n' + % (typename, l._template, l._posns)) + def substitute(l, values): build = copy.deepcopy(l._template) for (k,v) in values.items(): @@ -68,15 +95,15 @@ class DonorImplementation(): # assembling structs # sigh, we have to record the order of the arguments! - def _find_fields(typename): + def _find_fields(di, typename): try: fields = di._structs[typename] - except AttributeError: + except KeyError: fields = DonorStructLayout(typename) di._structs[typename] = fields return fields - def _make(typename, values): + def _make(di, typename, values): fields = di._find_fields(typename) return fields.substitute(values) @@ -85,22 +112,23 @@ class DonorImplementation(): def _func(di, functype, funcname, realargs): expr = '((%s) %s) %s' % (functype, funcname, realargs) - return gdb.parse_and_eval(expr) + return parse_eval(expr) def _must_func(di, functype, funcname, realargs): retval = di._func(functype, funcname, realargs) if retval < 0: - errnoval = gdb.parse_and_eval('errno') + errnoval = parse_eval('errno') 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', map(str,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', { @@ -111,7 +139,7 @@ class DonorImplementation(): }) 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)) ) @@ -146,7 +174,7 @@ class DonorImplementation(): '("%s", %d)' % (_string_escape_for_c(path), mode) ) if r < 0: - errnoval = gdb.parse_and_eval('errno') + errnoval = parse_eval('errno') if errnoval != os.errno.EEXIST: raise RuntimeError("mkdir %s failed: `%s'" % (repr(path), os.strerror(errnoval))) @@ -154,19 +182,29 @@ class DonorImplementation(): return 1 def _errno_save(di): - di._saved_errno = gdb.parse_and_eval('errno') + # 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. + # 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) + # Anyway: + di._saved_errno = parse_eval_via_print('errno') def _errno_restore(di): to_restore = di._saved_errno di._saved_errno = None if to_restore is not None: - gdb.parse_and_eval('errno = %d' % to_restore) + parse_eval_via_print('errno = %d' % to_restore) - # main entrypoints + def _result(di, output): + sys.stderr.write("#> %s" % output) + di._result_stream.write(output) + di._result_stream.flush() - def result(di, output): - di._result_stram.write(output) - di._result_stram.flush() + # main entrypoints def donate(di, path, control_msg): # control_msg is an array of integers being the ancillary data @@ -201,17 +239,22 @@ class DonorImplementation(): def mkdir(di, path): try: di._errno_save() - val = di._mkdir(path, '0700') + val = di._mkdir(path, int('0700', 8)) finally: di._errno_restore() di._result('%d\n' % val) def _protocol_read(di): - return 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): while True: di._result('!\n') cmd = di._protocol_read() + if cmd is None: break eval(cmd)