External UNIX socket - Revision history

Kir: /* Using the option */ use template:opt

2017-06-23T22:01:52Z

Using the option: use template:opt

Kir: /* stream/seqpacket */ fix restore syntax

2016-10-28T22:08:51Z

stream/seqpacket: fix restore syntax

Xemul: /* Old days */

2016-10-25T13:54:14Z

Old days

Xemul: /* See also */

2016-09-26T10:59:16Z

Xemul: /* socketpair */

2016-09-26T10:58:15Z

socketpair

Xemul: /* stream/seqpacket */

2016-09-26T10:57:49Z

stream/seqpacket

Xemul at 10:57, 26 September 2016

2016-09-26T10:57:18Z

Kir: /* stream/seqpacket */ fix formatting

2016-09-21T22:16:46Z

stream/seqpacket: fix formatting

Xemul at 10:15, 21 September 2016

2016-09-21T10:15:03Z

Xemul at 10:12, 21 September 2016

2016-09-21T10:12:28Z

@@ Line 13: / Line 13: @@
 However, sometimes it is possible to dump and successfully restore only one end of a unix socket pair. One particular example is the datagram sockets with on-way connection (client to server) used e.g. by <code>logd</code>. Server opens a datagram socket and waits on it for messages to be written into a log file. Processes using logd also create datagram sockets and connect those to the server. These connections are thus uni-directional. In this case it is possible to dump a program with the client-side socket and on restore the socket needs to be reconnected back to the original server.
-This is when <code>--external[...]</code> option should be used. By providing this option for both dump (now) and restore (in plans) commands, user states "I know there may be uni-directional dgram unix connections, and I will make sure the server end will exist on restore".
+This is when {{Opt|--external}} option should be used. By providing this option for both dump (now) and restore (in plans) commands, user states "I know there may be uni-directional dgram unix connections, and I will make sure the server end will exist on restore".
 For '''criu dump''', this option enables dumping ''datagram'' unix sockets with additional information about that other ("external") socket it is connected to.

@@ Line 31: / Line 31: @@
 * On dump, the <code>--external unix[id]</code> says that socket with <code>''id''</code> is OK to be disconnected
-* On restore, the <code>--external ''id''[=''path'']</code> says that the socket <code>''id''</code> should be reconnected back to the path it say on dump (or to the specified <code>''path''</code>) (THIS IS IN PLANS!)
+* On restore, the <code>--external unix[''id'']:''path''</code> says that the socket <code>''id''</code> should be reconnected back to the path it say on dump (or to the specified <code>''path''</code>) (THIS IS IN PLANS!)
 === socketpair ===

@@ Line 50: / Line 50: @@
 == Old days ==
-In earlier version of CRIU the same thing was specified with <code>-x|--ext-unix-sk</code> option. Note, that the <code>id</code> argument was optional and made CRIU treat as external any unconnected socket.
+For now the same thing is specified with <code>-x|--ext-unix-sk</code> option. Note, that the <code>id</code> argument was optional and made CRIU treat as external any unconnected socket. Soon this option will be [[deprecation|deprecated]].
 == See also ==

← Older revision		Revision as of 10:59, 26 September 2016
Line 47:		Line 47:

	Test is available for this feature, see test/socketpairs in criu sources.		Test is available for this feature, see test/socketpairs in criu sources.
		+
		+	== Old days ==
		+
		+	In earlier version of CRIU the same thing was specified with <code>-x\|--ext-unix-sk</code> option. Note, that the <code>id</code> argument was optional and made CRIU treat as external any unconnected socket.

	== See also ==		== See also ==

@@ Line 37: / Line 37: @@
 Unnamed unix sockets created with <code>socketpair()</code> system call can be dumped and restored.
-On dump, put inode of this socket in <code>--ext-unix-sk</code> option, for example:
+On dump, tell inode of this socket to CRIU, like this
   criu dump -D images -o dump.log -v4 --external unix[11890815] -t 16528

@@ Line 28: / Line 28: @@
 the other one will see EOF on the socket and may close it.
-The plan for this is to extend the <code>--ext-unix-sk</code> semantics to work like this:
+The plan for this is to extend the <code>--external unix[...]</code> semantics to work like this:
 * On dump, the <code>--external unix[id]</code> says that socket with <code>''id''</code> is OK to be disconnected
-* On restore, the <code>--ext-unix-sk ''id''[=''path'']</code> says that the socket <code>''id''</code> should be reconnected back to the path it say on dump (or to the specified <code>''path''</code>) (THIS IS IN PLANS!)
+* On restore, the <code>--external ''id''[=''path'']</code> says that the socket <code>''id''</code> should be reconnected back to the path it say on dump (or to the specified <code>''path''</code>) (THIS IS IN PLANS!)
 === socketpair ===

@@ Line 1: / Line 1: @@
-This explains the meaning of '''external socket is used''' error message, and the purpose of '''<code>--ext-unix-sk</code>''' option.
+This explains the meaning of '''external socket is used''' error message, and the purpose of '''<code>--external unix[...]</code>''' option.
 == Error meaning ==
@@ Line 13: / Line 13: @@
 However, sometimes it is possible to dump and successfully restore only one end of a unix socket pair. One particular example is the datagram sockets with on-way connection (client to server) used e.g. by <code>logd</code>. Server opens a datagram socket and waits on it for messages to be written into a log file. Processes using logd also create datagram sockets and connect those to the server. These connections are thus uni-directional. In this case it is possible to dump a program with the client-side socket and on restore the socket needs to be reconnected back to the original server.
-This is when <code>--ext-unix-sk</code> option should be used. By providing this option (for both dump and restore commands), user states "I know there may be uni-directional dgram unix connections, and I will make sure the server end will exist on restore".
+This is when <code>--external[...]</code> option should be used. By providing this option for both dump (now) and restore (in plans) commands, user states "I know there may be uni-directional dgram unix connections, and I will make sure the server end will exist on restore".
 For '''criu dump''', this option enables dumping ''datagram'' unix sockets with additional information about that other ("external") socket it is connected to.
@@ Line 30: / Line 30: @@
 The plan for this is to extend the <code>--ext-unix-sk</code> semantics to work like this:
-* On dump, the <code>--ext-unix-sk ''id''</code> says that socket with <code>''id''</code> is OK to be disconnected
+* On dump, the <code>--external unix[id]</code> says that socket with <code>''id''</code> is OK to be disconnected
-* On restore, the <code>--ext-unix-sk ''id''[=''path'']</code> says that the socket <code>''id''</code> should be reconnected back to the path it say on dump (or to the specified <code>''path''</code>).
+* On restore, the <code>--ext-unix-sk ''id''[=''path'']</code> says that the socket <code>''id''</code> should be reconnected back to the path it say on dump (or to the specified <code>''path''</code>) (THIS IS IN PLANS!)
 === socketpair ===
@@ Line 39: / Line 39: @@
 On dump, put inode of this socket in <code>--ext-unix-sk</code> option, for example:
-  criu dump -D images -o dump.log -v4 --ext-unix-sk=11890815 -t 16528
+  criu dump -D images -o dump.log -v4 --external unix[11890815] -t 16528
 On restore, the server should create a new pair and call <code>criu restore</code> asking it to [[Inheriting FDs on restore|inherit]] one.

@@ Line 55: / Line 55: @@
 [[Category:HOWTO]]
 [[Category:API]]
 [[Category:External]]
 [[Category:Sockets]]

← Older revision		Revision as of 10:12, 21 September 2016
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	[[Category:Network]]		[[Category:Network]]
	[[Category:External]]		[[Category:External]]
		+	[[Category:Sockets]]