r94109 MediaWiki - Code Review archive

Repository:MediaWiki
Revision:< r94108‎ | r94109 | r94110 >
Date:14:40, 9 August 2011
Author:mark
Status:ok
Tags:
Comment:
Move createDaemon into util.py
Modified paths:
  • /trunk/udpmcast/htcpseqcheck.py (modified) (history)
  • /trunk/udpmcast/udpmcast.py (modified) (history)
  • /trunk/udpmcast/util.py (added) (history)

Diff [purge]

Index: trunk/udpmcast/util.py
——@@ -0,0 +1,78 @@
 2+# util.py
 3+# utility functions shared by udpmcast and htcpseqcheck
 4+
 5+import os, signal
 6+
 7+def createDaemon():
 8+ """
 9+ Detach a process from the controlling terminal and run it in the
 10+ background as a daemon.
 11+ """
 12+
 13+ try:
 14+ # Fork a child process so the parent can exit. This will return control
 15+ # to the command line or shell. This is required so that the new process
 16+ # is guaranteed not to be a process group leader. We have this guarantee
 17+ # because the process GID of the parent is inherited by the child, but
 18+ # the child gets a new PID, making it impossible for its PID to equal its
 19+ # PGID.
 20+ pid = os.fork()
 21+ except OSError, e:
 22+ return((e.errno, e.strerror)) # ERROR (return a tuple)
 23+
 24+ if (pid == 0): # The first child.
 25+
 26+ # Next we call os.setsid() to become the session leader of this new
 27+ # session. The process also becomes the process group leader of the
 28+ # new process group. Since a controlling terminal is associated with a
 29+ # session, and this new session has not yet acquired a controlling
 30+ # terminal our process now has no controlling terminal. This shouldn't
 31+ # fail, since we're guaranteed that the child is not a process group
 32+ # leader.
 33+ os.setsid()
 34+
 35+ # When the first child terminates, all processes in the second child
 36+ # are sent a SIGHUP, so it's ignored.
 37+ signal.signal(signal.SIGHUP, signal.SIG_IGN)
 38+
 39+ try:
 40+ # Fork a second child to prevent zombies. Since the first child is
 41+ # a session leader without a controlling terminal, it's possible for
 42+ # it to acquire one by opening a terminal in the future. This second
 43+ # fork guarantees that the child is no longer a session leader, thus
 44+ # preventing the daemon from ever acquiring a controlling terminal.
 45+ pid = os.fork() # Fork a second child.
 46+ except OSError, e:
 47+ return((e.errno, e.strerror)) # ERROR (return a tuple)
 48+
 49+ if (pid == 0): # The second child.
 50+ # Ensure that the daemon doesn't keep any directory in use. Failure
 51+ # to do this could make a filesystem unmountable.
 52+ os.chdir("/")
 53+ # Give the child complete control over permissions.
 54+ os.umask(0)
 55+ else:
 56+ os._exit(0) # Exit parent (the first child) of the second child.
 57+ else:
 58+ os._exit(0) # Exit parent of the first child.
 59+
 60+ # Close all open files. Try the system configuration variable, SC_OPEN_MAX,
 61+ # for the maximum number of open files to close. If it doesn't exist, use
 62+ # the default value (configurable).
 63+ try:
 64+ maxfd = os.sysconf("SC_OPEN_MAX")
 65+ except (AttributeError, ValueError):
 66+ maxfd = 256 # default maximum
 67+
 68+ for fd in range(0, maxfd):
 69+ try:
 70+ os.close(fd)
 71+ except OSError: # ERROR (ignore)
 72+ pass
 73+
 74+ # Redirect the standard file descriptors to /dev/null.
 75+ os.open("/dev/null", os.O_RDONLY) # standard input (0)
 76+ os.open("/dev/null", os.O_RDWR) # standard output (1)
 77+ os.open("/dev/null", os.O_RDWR) # standard error (2)
 78+
 79+ return(0)
Property changes on: trunk/udpmcast/util.py
___________________________________________________________________
Added: svn:mime-type
180 + text/plain
Index: trunk/udpmcast/udpmcast.py
——@@ -6,84 +6,10 @@
77 #
88 # $Id$
99
10 -import socket, getopt, sys, os, signal, pwd, grp
 10+import socket, getopt, sys, pwd, grp
1111
1212 debugging = False
1313
14 -def createDaemon():
15 - """
16 - Detach a process from the controlling terminal and run it in the
17 - background as a daemon.
18 - """
19 -
20 - try:
21 - # Fork a child process so the parent can exit. This will return control
22 - # to the command line or shell. This is required so that the new process
23 - # is guaranteed not to be a process group leader. We have this guarantee
24 - # because the process GID of the parent is inherited by the child, but
25 - # the child gets a new PID, making it impossible for its PID to equal its
26 - # PGID.
27 - pid = os.fork()
28 - except OSError, e:
29 - return((e.errno, e.strerror)) # ERROR (return a tuple)
30 -
31 - if (pid == 0): # The first child.
32 -
33 - # Next we call os.setsid() to become the session leader of this new
34 - # session. The process also becomes the process group leader of the
35 - # new process group. Since a controlling terminal is associated with a
36 - # session, and this new session has not yet acquired a controlling
37 - # terminal our process now has no controlling terminal. This shouldn't
38 - # fail, since we're guaranteed that the child is not a process group
39 - # leader.
40 - os.setsid()
41 -
42 - # When the first child terminates, all processes in the second child
43 - # are sent a SIGHUP, so it's ignored.
44 - signal.signal(signal.SIGHUP, signal.SIG_IGN)
45 -
46 - try:
47 - # Fork a second child to prevent zombies. Since the first child is
48 - # a session leader without a controlling terminal, it's possible for
49 - # it to acquire one by opening a terminal in the future. This second
50 - # fork guarantees that the child is no longer a session leader, thus
51 - # preventing the daemon from ever acquiring a controlling terminal.
52 - pid = os.fork() # Fork a second child.
53 - except OSError, e:
54 - return((e.errno, e.strerror)) # ERROR (return a tuple)
55 -
56 - if (pid == 0): # The second child.
57 - # Ensure that the daemon doesn't keep any directory in use. Failure
58 - # to do this could make a filesystem unmountable.
59 - os.chdir("/")
60 - # Give the child complete control over permissions.
61 - os.umask(0)
62 - else:
63 - os._exit(0) # Exit parent (the first child) of the second child.
64 - else:
65 - os._exit(0) # Exit parent of the first child.
66 -
67 - # Close all open files. Try the system configuration variable, SC_OPEN_MAX,
68 - # for the maximum number of open files to close. If it doesn't exist, use
69 - # the default value (configurable).
70 - try:
71 - maxfd = os.sysconf("SC_OPEN_MAX")
72 - except (AttributeError, ValueError):
73 - maxfd = 256 # default maximum
74 -
75 - for fd in range(0, maxfd):
76 - try:
77 - os.close(fd)
78 - except OSError: # ERROR (ignore)
79 - pass
80 -
81 - # Redirect the standard file descriptors to /dev/null.
82 - os.open("/dev/null", os.O_RDONLY) # standard input (0)
83 - os.open("/dev/null", os.O_RDWR) # standard output (1)
84 - os.open("/dev/null", os.O_RDWR) # standard error (2)
85 -
86 - return(0)
87 -
8814 def debug(msg):
8915 global debugging
9016 if debugging:
——@@ -177,6 +103,7 @@
178104
179105 # Become a daemon
180106 if daemon:
 107+ from util import createDaemon
181108 createDaemon()
182109
183110 # Open the UDP socket
Index: trunk/udpmcast/htcpseqcheck.py
——@@ -6,7 +6,7 @@
77 #
88 # $Id$
99
10 -import socket, getopt, sys, os, signal, pwd, grp, struct
 10+import socket, getopt, sys, pwd, grp, struct
1111
1212 from datetime import datetime, timedelta
1313 from collections import deque
——@@ -94,81 +94,6 @@
9595
9696 self.counts.update(counts)
9797
98 -
99 -def createDaemon():
100 - """
101 - Detach a process from the controlling terminal and run it in the
102 - background as a daemon.
103 - """
104 -
105 - try:
106 - # Fork a child process so the parent can exit. This will return control
107 - # to the command line or shell. This is required so that the new process
108 - # is guaranteed not to be a process group leader. We have this guarantee
109 - # because the process GID of the parent is inherited by the child, but
110 - # the child gets a new PID, making it impossible for its PID to equal its
111 - # PGID.
112 - pid = os.fork()
113 - except OSError, e:
114 - return((e.errno, e.strerror)) # ERROR (return a tuple)
115 -
116 - if (pid == 0): # The first child.
117 -
118 - # Next we call os.setsid() to become the session leader of this new
119 - # session. The process also becomes the process group leader of the
120 - # new process group. Since a controlling terminal is associated with a
121 - # session, and this new session has not yet acquired a controlling
122 - # terminal our process now has no controlling terminal. This shouldn't
123 - # fail, since we're guaranteed that the child is not a process group
124 - # leader.
125 - os.setsid()
126 -
127 - # When the first child terminates, all processes in the second child
128 - # are sent a SIGHUP, so it's ignored.
129 - signal.signal(signal.SIGHUP, signal.SIG_IGN)
130 -
131 - try:
132 - # Fork a second child to prevent zombies. Since the first child is
133 - # a session leader without a controlling terminal, it's possible for
134 - # it to acquire one by opening a terminal in the future. This second
135 - # fork guarantees that the child is no longer a session leader, thus
136 - # preventing the daemon from ever acquiring a controlling terminal.
137 - pid = os.fork() # Fork a second child.
138 - except OSError, e:
139 - return((e.errno, e.strerror)) # ERROR (return a tuple)
140 -
141 - if (pid == 0): # The second child.
142 - # Ensure that the daemon doesn't keep any directory in use. Failure
143 - # to do this could make a filesystem unmountable.
144 - os.chdir("/")
145 - # Give the child complete control over permissions.
146 - os.umask(0)
147 - else:
148 - os._exit(0) # Exit parent (the first child) of the second child.
149 - else:
150 - os._exit(0) # Exit parent of the first child.
151 -
152 - # Close all open files. Try the system configuration variable, SC_OPEN_MAX,
153 - # for the maximum number of open files to close. If it doesn't exist, use
154 - # the default value (configurable).
155 - try:
156 - maxfd = os.sysconf("SC_OPEN_MAX")
157 - except (AttributeError, ValueError):
158 - maxfd = 256 # default maximum
159 -
160 - for fd in range(0, maxfd):
161 - try:
162 - os.close(fd)
163 - except OSError: # ERROR (ignore)
164 - pass
165 -
166 - # Redirect the standard file descriptors to /dev/null.
167 - os.open("/dev/null", os.O_RDONLY) # standard input (0)
168 - os.open("/dev/null", os.O_RDWR) # standard output (1)
169 - os.open("/dev/null", os.O_RDWR) # standard error (2)
170 -
171 - return(0)
172 -
17398 def receive_htcp(sock):
17499 portnr = sock.getsockname()[1];
175100
——@@ -276,6 +201,7 @@
277202
278203 # Become a daemon
279204 if daemon:
 205+ from util import createDaemon
280206 createDaemon()
281207
282208 # Open the UDP socket

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