+# fish.py
+
+# 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.
+
# python 3 only
import socket
import subprocess
import os
import pwd
+import struct
+import tempfile
+import shutil
+import sys
def _shuffle_fd3():
os.dup2(1,3)
os.dup2(2,1)
+class Error(Exception): pass
+
class Donor():
- def __init__(d, pid):
- d._pid = pid
+ def __init__(d, pid, debug=None):
+ d.pid = pid
+ if debug is None:
+ d._stderr = tempfile.TemporaryFile(mode='w+')
+ else:
+ d._stderr = None
d._sp = subprocess.Popen(
preexec_fn = _shuffle_fd3,
stdin = subprocess.PIPE,
stdout = subprocess.PIPE,
+ stderr = d._stderr,
close_fds = False,
args = ['gdb', '-p', str(pid), '-batch', '-ex',
'python import fishdescriptor.indonor as id;'+
)
def _eval_integer(d, expr):
- l = d._sp.stdout.readline()
- if l != b'!\n': raise RuntimeError("indonor said %s" % repr(l))
- d._sp.stdin.write(expr.encode('utf-8') + b'\n')
- d._sp.stdin.flush()
- l = d._sp.stdout.readline().rstrip(b'\n')
- return int(l)
+ try:
+ l = d._sp.stdout.readline()
+ if not len(l): raise Error('gdb process donor python repl quit')
+ if l != b'!\n': raise RuntimeError("indonor said %s" % repr(l))
+ d._sp.stdin.write(expr.encode('utf-8') + b'\n')
+ d._sp.stdin.flush()
+ l = d._sp.stdout.readline().rstrip(b'\n')
+ return int(l)
+ except Exception as e:
+ if d._stderr is not None:
+ d._stderr.seek(0)
+ shutil.copyfileobj(d._stderr, sys.stderr)
+ d._stderr.seek(0)
+ d._stderr.truncate()
+ raise e
def _eval_success(d, expr):
r = d._eval_integer(expr)
if oe.errno != os.errno.ENOENT: raise oe
return False
- def _sock_dir(d, target_euid):
+ def _sock_dir(d, target_euid, target_root):
run_dir = '/run/user/%d' % target_euid
if d._exists(run_dir):
return run_dir + '/fishdescriptor'
def fish(d, fds):
# -> list of fds in our process
+ target_root = '/proc/%d/root' % d.pid
+ if not d._exists(target_root):
+ target_root = ''
+
euid = d._geteuid()
- sockdir = d._sock_dir(euid)
+ sockdir = d._sock_dir(euid, target_root)
d.mkdir(sockdir)
- sockname = '%s/%s,%d' % (sockdir, os.uname().nodename, d._pid)
-
- target_root = '/proc/%d/root' % d._pid
- if not d._exists(target_root):
- target_root = ''
+ sockname = '%s/%s,%d' % (sockdir, os.uname().nodename, d.pid)
our_sockname = target_root + sockname
s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
s.bind(our_sockname)
+ os.chmod(our_sockname, 666)
s.listen(1)
- ancil_len = d.donate(our_sockname, fds)
+ ancil_len = d.donate(sockname, fds)
(s2, dummy) = s.accept()
(msg, ancil, flags, sender) = s2.recvmsg(1, ancil_len)
- got_fds = [ ]
+ got_fds = None
+ unpack_fmt = '%di' % len(fds)
for clvl, ctype, cdata in ancil:
if clvl == socket.SOL_SOCKET and ctype == socket.SCM_RIGHTS:
- got_fds += cdata # need to trim any surplus, and unpack
+ assert(got_fds is None)
+ got_fds = struct.unpack_from(unpack_fmt, cdata)
finally:
if s is not None: s.close()
try: os.remove(our_sockname)
except FileNotFoundError: pass
+
+ return list(got_fds)
+
+ def detach(d):
+ d._sp.stdin.close()