From 8bffa1c19fd05f4f04dad4b5b98f85b94f23113c Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Mon, 26 Jan 2015 22:26:57 +0000 Subject: - added s6-fdholder-delete(c) - small s6-fdholder-* fixes - s6-fdholder documentation (in review) - s6_svstatus_* bugfix (thanks Olivier Brunel) --- doc/s6-fdholder-retrieve.html | 98 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 doc/s6-fdholder-retrieve.html (limited to 'doc/s6-fdholder-retrieve.html') diff --git a/doc/s6-fdholder-retrieve.html b/doc/s6-fdholder-retrieve.html new file mode 100644 index 0000000..5231051 --- /dev/null +++ b/doc/s6-fdholder-retrieve.html @@ -0,0 +1,98 @@ + + + + + s6: the s6-fdholder-retrieve program + + + + + + +

+s6
+Software
+skarnet.org +

+ +

The `s6-fdholder-retrieve` program

+ +

+s6-fdholder-retrieve connects to a +fd-holding daemon listening on a +Unix domain socket, and retrieves a file descriptor from that +daemon, then executes a program with that file descriptor as the +program's standard input. +

+ +

Interface

+ +

+     s6-fdholder-retrieve [ -D ] [ -t timeout ] path id prog...
+

+ +

s6-fdholder-retrieve executes into s6-ipcclient path +s6-fdholder-retrievec id prog.... +It does nothing else: it is just a convenience program. +The s6-ipcclient program connects +to a Unix socket at path, and the +s6-fdholder-retrievec program +gets the file descriptor identified by id over the socket.
It should be used to connect to a +s6-fdholderd daemon, which will pass the +file descriptor to the client over the path socket.
It executes into prog... with the retrieved file +descriptor as prog...'s standard input.

+ +

Options

+ +

-D : delete the file descriptor from the server's +storage after retrieval. This option requires writing rights over the +given identifier as well as reading rights: check the server's +configuration.
-t timeout : if the operation cannot be +processed in timeout milliseconds, then fail with an error message. +Communications with the server should be near-instant, so this option is +only here to protect users against programming errors (connecting to the +wrong socket, for instance).

+ +

Usage example

+ +

+   s6-fdholder-store /service/fdholderd/s MYSOCKET s6-ipcserverd cat
+

+ +

+ will retrieve a file descriptor stored under the MYSOCKET identifier in +the s6-fdholderd daemon listening on the /service/fdholderd/s +socket, and execute into s6-ipcserverd cat with that file +descriptor as stdin. In this case, if MYSOCKET referred to a Unix domain +socket, s6-ipcserverd will then accept +client connections on it and spawn a cat program for every +connection. +

+ +

Notes

+ +

s6-fdholder-retrieve really executes into s6-ipcclient +s6-fdholder-retrievec +fdclose +6 fdclose 7 prog..., so that prog... does not +have a connection with the fd-holding daemon anymore. If you want to +keep the server connection open for prog..., use +s6-ipcclient s6-fdholder-retrievec manually.
To execute prog with the newly retrieved file descriptor +as number n while preserving stdin, use the following construct: +fdmove n 0 s6-fdholder-retrieve path id +fdswap +0 n prog.... Be aware that n +cannot be 6 or 7, internally used by s6-fdholder-retrieve.

+ + + -- cgit v1.2.3

The s6-fdholder-retrieve program

Interface

Options

Usage example

Notes

The `s6-fdholder-retrieve` program