4 import fishdescriptor.fish
10 usage = '''fishdescriptor [-p|--pid] <pid> <action>... [-p|--pid <pid> <action>...]
13 [<here-0fd>=]<there-fd>
14 fish the openfile referenced by descriptor <there-fd> in
15 (the most recent) <pid> and keep a descriptor onto it;
16 and, optionally, give it the number <here-fd> for exec
17 exec <program> [<arg>...]
18 execute a process with each specified <here>
21 calls getsockname/getpeername on the most recent
25 now attach to <pid>, detaching from previous pid
29 # list of (nominal, there) where nominal might be None
32 # fdmap[nominal] = (actual, Donor, there)
34 def implement_pending():
35 actuals = donor.fish([pend[1] for pend in pending])
36 assert(len(actuals) == len(pending))
37 for (nominal, there), actual in zip(pending, actuals):
38 overwriting_info = fdmap.get(nominal)
39 if overwriting_info is not None: os.close(overwriting_info[0])
40 fdmap[nominal] = (actual, Donor, there)
42 def implmement_sockinfo(nominal):
43 (actual, tdonor, there) = fdmap[nominal]
44 # socket.fromfd requires the AF. But of course we don't know the AF.
45 # There isn't a sane way to get it in Python:
46 # https://utcc.utoronto.ca/~cks/space/blog/python/SocketFromFdMistake
48 # https://github.com/tiran/socketfromfd
49 # adds a dependency, not portable due to reliance on SO_DOMAIN
50 # call getsockname using ctypes
51 # no sane way to discover how to unpack sa_family_t
56 my $sa = getsockname STDIN;
57 exit 0 if !defined $sa and $!==ENOTSOCK;
58 my $family = sockaddr_family $sa;
59 print $family, "\n" or die $!;
61 famp = subprocess.Popen(
63 stdout = subprocess.PIPE,
64 args = ['perl','-we',perl_script]
66 (output, dummy) = famp.communicate()
69 sock = socket.fromfd(fd, family, 0)
71 print("[%s] %d sockinfo" % (tdonor.pid, there), end='')
72 for f in (lambda: socket.AddressFamily(family).name,
73 lambda: repr(sock.getsockname()),
74 lambda: repr(sock.getpeername())):
76 except Exception as e: info = repr(e)
77 print("\t", info, sep='', end='')
82 def permute_fds_for_exec():
83 actual2intended = { info[0]: nominal for nominal, info in fdmap.items }
84 # invariant at the start of each loop iteration:
85 # for each intended (aka `nominal') we have processed:
86 # relevant open-file is only held in fd intended
87 # (unless `nominal' is None in which case it is closed)
88 # for each intended (aka `nominal') we have NOT processed:
89 # relevant open-file is only held in actual
90 # where actual = fdmap[nominal][0]
91 # and where actual2intended[actual] = nominal
92 # we can rely on processing each intended only once,
93 # since they're hash keys
94 # the post-condition is not really a valid state (fdmap
95 # is nonsense) but we call this function just before exec
96 for intended, (actual, tdonor, there) in fdmap.items():
97 if intended == actual:
99 if intended is not None:
100 inway_intended = actual2intended.get(intended)
101 if inway_intended is not None:
102 inway_moved = os.dup(intended)
103 actual2intended[inway_moved] = inway_intended
104 fdmap[inway_intented][0] = inway_moved
105 os.dup2(actual, intended)
108 def implement_exec(argl):
109 if donor is not None: donor.detach()
111 permut_fds_for_exec()
112 os.execvp(argl[0], argl)
116 if donor is not None: donor.detach()
117 donor = fishdescriptor.fish.Donor(pid)
119 def ocb_set_donor(option, opt, value, parser):
122 ov = optparse.Values()
129 def arg_matches(regexp):
131 m = re.search(regexp, arg)
134 op = optparse.OptionParser(usage=usage)
136 op.disable_interspersed_args()
137 op.add_option('-p','--pid', type='int', action='callback',
138 callback=ocb_set_donor)
144 (ov, args) = op.parse_args(args=args, values=ov)
145 if not len(args): break
149 if donor is not None:
151 elif arg_matches(r'^(?:(\d+)=)?(\d+)?$'):
152 (nominal, there) = m.groups()
153 nominal = None if nominal is None else int(nominal)
155 pending.append((nominal,there))
156 last_nominal = nominal
159 op.error("exec needs command to run")
162 elif arg == 'sockinfo':
163 if last_nominal is None:
164 op.error('sockinfo needs a prior fd spec')
166 implement_sockinfo(last_nominal)
168 op.error("unknown argument/option `%s'" % arg)