From 5abe508bfef8372472d66adf69cf08e07125820c Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Tue, 21 Nov 2017 16:12:18 +0000 Subject: Initial commit --- doc/skabus-dyntee.html | 123 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 123 insertions(+) create mode 100644 doc/skabus-dyntee.html (limited to 'doc/skabus-dyntee.html') diff --git a/doc/skabus-dyntee.html b/doc/skabus-dyntee.html new file mode 100644 index 0000000..57b34f3 --- /dev/null +++ b/doc/skabus-dyntee.html @@ -0,0 +1,123 @@ + + + + + + skabus: the skabus-dyntee program + + + + + + +

+skabus
+Software
+skarnet.org +

+ +

The `skabus-dyntee` program

+ +

+skabus-dyntee is a dynamic tee, which is the +simplest publisher daemon possible. +It listens on a Unix domain socket, accepts client connections, and +publishes to its clients everything it reads on its standard +input, as a byte stream. It only writes to clients and never reads +from them. +

+ +

Interface

+ +

+     skabus-dyntee [ -1 ] [ -D | -d ] [ -c maxconn ] [ -b backlog ] [ -G gidlist ] [ -g gid ] [ -u uid ] [ -U ] [ -t clienttimeout ] [ -T lameducktimeout ] [ -i rulesdir | -x rulesfile ] path
+

+ +

skabus-dyntee binds to the Unix domain socket at path.
If applicable, it drops root privileges.
It listens to its socket and accepts client connections.
Whenever it has data available on its standard input, it reads +that data and writes it to every client it has. It duplicates its +stdin stream to all its clients, hence the name dynamic tee.
When it reads EOF on its stdin, or when it receives a SIGTERM, +it waits for its clients to read their pending data, then exits 0.

+ +

+ skabus-dyntee is just a wrapper that binds to its socket and +drops privileges before executing into +skabus-dynteed. For details of +the daemon's operation, see the +skabus-dynteed documentation. +

+ +

Options

+ +

-1 : write a newline to stdout, before +closing it, right after binding and listening to the Unix socket. +If stdout is suitably redirected, this can be used by monitoring +programs to check when the server is ready to accept connections.
-d : allow instant rebinding to the same path +even if it has been used not long ago - this is the SO_REUSEADDR flag to +setsockopt() +and is generally used with server programs. This is the default. Note that +path will be deleted if it already exists at program start time.
-D : disallow instant rebinding to the same path.
-c maxconn : accept at most +maxconn concurrent client connections. Default is 40. It is +impossible to set it higher than the value of the SKABUS_DYNTEE_MAX macro, +which is 1000. +
-b backlog : set a maximum of +backlog backlog connections on the socket. Extra +connection attempts will rejected by the kernel.
-G gidlist : change skabus-dyntee's +supplementary group list to gidlist after binding the socket. +This is only valid when run as root. gidlist must be a +comma-separated list of numerical group IDs.
-g gid : change skabus-dyntee's groupid +to gid after binding the socket. This is only valid when run +as root.
-u uid : change skabus-dyntee's userid +to uid after binding the socket. This is only valid when run +as root.
-U : change skabus-dyntee's user id, group id and +supplementary group list +according to the values of the UID, GID and GIDLIST environment variables +after binding the socket. This is only valid when run as root. +This can be used with the +s6-envuidgid +program to easily script a service that binds to a privileged socket +then drops its privileges to those of a named non-root account.
-t clienttimeout : disconnect a client +that has not read its data after clienttimeout milliseconds. +By default, clienttimeout is 0, which means infinite.
-T lameducktimeout : after +skabus-dyntee has been told to exit, clients will have +lameducktimeout milliseconds to read their pending data, +after which skabus-dyntee will exit anyway. +By default, lameducktimeout is 0, which means infinite.
-x rulesfile : read access rights +configuration from CDB file rulesfile.
-i rulesdir : read access rights +configuration from the filesystem in directory rulesdir.

+ +

Notes

+ +

skabus-dyntee does not interpret its options itself. It just +dispatches them to the appropriate program on the command line that +it builds.
From the user's point of view, skabus-dyntee behaves like a +long-lived process, even if the long-lived process itself is called +skabus-dynteed. Every operational detail +of skabus-dynteed applies to skabus-dyntee as well; in particular, +make sure to properly +configure the clients' +access rights.

+ + + -- cgit v1.3.1

The skabus-dyntee program

Interface

Options

Notes

The `skabus-dyntee` program