From bef76b45f480aa41209efdec09fc6bb0bfde7cbe Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Sat, 30 Sep 2023 05:40:04 +0000 Subject: Great Tcpserver Unification. Prepare for 2.6.0.0. Signed-off-by: Laurent Bercot --- doc/s6-tcpserver6.html | 136 ------------------------------------------------- 1 file changed, 136 deletions(-) delete mode 100644 doc/s6-tcpserver6.html (limited to 'doc/s6-tcpserver6.html') diff --git a/doc/s6-tcpserver6.html b/doc/s6-tcpserver6.html deleted file mode 100644 index 01be274..0000000 --- a/doc/s6-tcpserver6.html +++ /dev/null @@ -1,136 +0,0 @@ - - - - - - s6-networking: the s6-tcpserver6 program - - - - - - -

- -

The `s6-tcpserver6` program

- -

-s6-tcpserver6 is a super-server for IPv6 TCP -connections. It accepts connections from clients, and forks a -program to handle each connection. -

- -

Interface

- -

-     s6-tcpserver6 [ -1 ] [ -v verbosity ] [ -c maxconn ] [ -C localmaxconn ] [ -b backlog ] [ -G gidlist ] [ -g gid ] [ -u uid ] [ -U ] ip port prog...
-

- -

s6-tcpserver6 binds to local IPv6 address ip, -port port.
It closes its stdin and stdout.
For every TCP connection to this address and port, it -forks. The child sets some environment variables, then -executes prog... with stdin reading from the network socket -and stdout writing to it.
Depending on the verbosity level, it logs what it does to stderr.
It runs until killed by a signal. Depending on the received -signal, it may kill its children before exiting.
s6-tcpserver6 actually doesn't do any of this itself. It is -a wrapper, rewriting the command line and executing into a chain -of programs that perform those duties.

- -

Environment variables

- -

- For each connection, an instance of prog... is spawned with -the following variables set: -

- -

PROTO: always set to TCP
TCPREMOTEIP: set to the originating address, in canonical IPv6 form
TCPREMOTEPORT: set to the originating port
TCPCONNNUM: set to the number of connections originating from -the same IPv6 address

- -

Options

- -

-1 : write port to stdout, before -closing it, right after binding and listening to the network socket. -If stdout is suitably redirected, this can be used by monitoring -programs to check when the server is ready to accept connections.
-v verbosity : be more or less verbose. -By default, verbosity is 1: print warning messages to stderr. -0 means only print fatal error messages ; 2 means print status and -connection information for every client.
-c maxconn : accept at most -maxconn concurrent connections. Default is 40. It is -impossible to set it higher than 1000.
-C localmaxconn : accept at most -localmaxconn connections from the same IP address. -Default is 40. It is impossible to set it higher than maxconn.
-b backlog : set a maximum of -backlog backlog connections on the socket. Extra -connection attempts will rejected by the kernel.
-G gidlist : change s6-tcpserver6'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 s6-tcpserver6's group id -to gid after binding the socket. This is only valid when run -as root.
-u uid : change s6-tcpserver6's user id -to uid after binding the socket. This is only valid when run -as root.
-U : change s6-tcpserver6'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.

- -

Signals

- -

SIGTERM: exit.
SIGHUP: send a SIGTERM and a SIGCONT to all children.
SIGQUIT: send a SIGTERM and a SIGCONT to all children, then exit.
SIGABRT: send a SIGKILL to all children, then exit.

- -

Notes

- -

s6-tcpserver6 will only serve real IPv6 addresses; it does not -default to an IPv4 address. The -s6-tcpserver4 program should be -used to serve IPv4 addresses.
s6-tcpserver6 will only work if the underlying -skalibs has -been compiled with IPv6 support.
In previous releases of s6-networking, s6-tcpserver6 was -monolithic: it did the work of -s6-tcpserver6-socketbinder, -s6-applyuidgid and -s6-tcpserver6d itself. The functionality has now -been split into several different programs because some service startup -schemes require the daemon to get its socket from an external -program instead of creating and binding it itself. The most obvious -application of this is upgrading a long-lived process without -losing existing connections.