1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
# Copyright 1999-2009 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Id$
from _emerge.SubProcess import SubProcess
from _emerge.PollConstants import PollConstants
import sys
from portage.cache.mappings import slot_dict_class
import portage
from portage import os
import fcntl
import errno
import array
class SpawnProcess(SubProcess):
"""
Constructor keyword args are passed into portage.process.spawn().
The required "args" keyword argument will be passed as the first
spawn() argument.
"""
_spawn_kwarg_names = ("env", "opt_name", "fd_pipes",
"uid", "gid", "groups", "umask", "logfile",
"path_lookup", "pre_exec")
__slots__ = ("args",) + \
_spawn_kwarg_names
_file_names = ("log", "process", "stdout")
_files_dict = slot_dict_class(_file_names, prefix="")
def _start(self):
if self.cancelled:
return
if self.fd_pipes is None:
self.fd_pipes = {}
fd_pipes = self.fd_pipes
fd_pipes.setdefault(0, sys.stdin.fileno())
fd_pipes.setdefault(1, sys.stdout.fileno())
fd_pipes.setdefault(2, sys.stderr.fileno())
# flush any pending output
for fd in fd_pipes.values():
if fd == sys.stdout.fileno():
sys.stdout.flush()
if fd == sys.stderr.fileno():
sys.stderr.flush()
logfile = self.logfile
self._files = self._files_dict()
files = self._files
master_fd, slave_fd = self._pipe(fd_pipes)
fcntl.fcntl(master_fd, fcntl.F_SETFL,
fcntl.fcntl(master_fd, fcntl.F_GETFL) | os.O_NONBLOCK)
null_input = None
fd_pipes_orig = fd_pipes.copy()
if self.background:
# TODO: Use job control functions like tcsetpgrp() to control
# access to stdin. Until then, use /dev/null so that any
# attempts to read from stdin will immediately return EOF
# instead of blocking indefinitely.
null_input = open('/dev/null', 'rb')
fd_pipes[0] = null_input.fileno()
else:
fd_pipes[0] = fd_pipes_orig[0]
files.process = os.fdopen(master_fd, 'rb')
if logfile is not None:
fd_pipes[1] = slave_fd
fd_pipes[2] = slave_fd
files.log = open(logfile, mode='ab')
portage.util.apply_secpass_permissions(logfile,
uid=portage.portage_uid, gid=portage.portage_gid,
mode=0o660)
if not self.background:
files.stdout = os.fdopen(os.dup(fd_pipes_orig[1]), 'wb')
output_handler = self._output_handler
else:
# Create a dummy pipe so the scheduler can monitor
# the process from inside a poll() loop.
fd_pipes[self._dummy_pipe_fd] = slave_fd
if self.background:
fd_pipes[1] = slave_fd
fd_pipes[2] = slave_fd
output_handler = self._dummy_handler
kwargs = {}
for k in self._spawn_kwarg_names:
v = getattr(self, k)
if v is not None:
kwargs[k] = v
kwargs["fd_pipes"] = fd_pipes
kwargs["returnpid"] = True
kwargs.pop("logfile", None)
self._reg_id = self.scheduler.register(files.process.fileno(),
self._registered_events, output_handler)
self._registered = True
retval = self._spawn(self.args, **kwargs)
os.close(slave_fd)
if null_input is not None:
null_input.close()
if isinstance(retval, int):
# spawn failed
self._unregister()
self.returncode = retval
self.wait()
return
self.pid = retval[0]
portage.process.spawned_pids.remove(self.pid)
def _pipe(self, fd_pipes):
"""
@type fd_pipes: dict
@param fd_pipes: pipes from which to copy terminal size if desired.
"""
return os.pipe()
def _spawn(self, args, **kwargs):
return portage.process.spawn(args, **kwargs)
def _output_handler(self, fd, event):
if event & PollConstants.POLLIN:
files = self._files
buf = array.array('B')
try:
buf.fromfile(files.process, self._bufsize)
except EOFError:
pass
if buf:
if not self.background:
write_successful = False
failures = 0
while True:
try:
if not write_successful:
buf.tofile(files.stdout)
write_successful = True
files.stdout.flush()
break
except IOError as e:
if e.errno != errno.EAGAIN:
raise
del e
failures += 1
if failures > 50:
# Avoid a potentially infinite loop. In
# most cases, the failure count is zero
# and it's unlikely to exceed 1.
raise
# This means that a subprocess has put an inherited
# stdio file descriptor (typically stdin) into
# O_NONBLOCK mode. This is not acceptable (see bug
# #264435), so revert it. We need to use a loop
# here since there's a race condition due to
# parallel processes being able to change the
# flags on the inherited file descriptor.
# TODO: When possible, avoid having child processes
# inherit stdio file descriptors from portage
# (maybe it can't be avoided with
# PROPERTIES=interactive).
fcntl.fcntl(files.stdout.fileno(), fcntl.F_SETFL,
fcntl.fcntl(files.stdout.fileno(),
fcntl.F_GETFL) ^ os.O_NONBLOCK)
buf.tofile(files.log)
files.log.flush()
else:
self._unregister()
self.wait()
self._unregister_if_appropriate(event)
return self._registered
def _dummy_handler(self, fd, event):
"""
This method is mainly interested in detecting EOF, since
the only purpose of the pipe is to allow the scheduler to
monitor the process from inside a poll() loop.
"""
if event & PollConstants.POLLIN:
buf = array.array('B')
try:
buf.fromfile(self._files.process, self._bufsize)
except EOFError:
pass
if buf:
pass
else:
self._unregister()
self.wait()
self._unregister_if_appropriate(event)
return self._registered
|