From ebfd0ba17e0d4b220725018d16e294e8e22a1745 Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Thu, 15 Jan 2015 20:51:39 +0000 Subject: Move Unix domain socket and access control stuff to s6. Move seekablepipe to s6-portable-utils. Version: 2.0.1.0, release candidate --- doc/s6-ipcserver.html | 173 -------------------------------------------------- 1 file changed, 173 deletions(-) delete mode 100644 doc/s6-ipcserver.html (limited to 'doc/s6-ipcserver.html') diff --git a/doc/s6-ipcserver.html b/doc/s6-ipcserver.html deleted file mode 100644 index 4b52888..0000000 --- a/doc/s6-ipcserver.html +++ /dev/null @@ -1,173 +0,0 @@ - - - - - s6-networking: the s6-ipcserver program - - - - - - -

- -

The `s6-ipcserver` program

- -

-s6-ipcserver is an -UCSPI server tool for -Unix domain sockets, i.e. a super-server. -It accepts connections from clients, and forks a -program to handle each connection. -

- -

Interface

- -

-     s6-ipcserver [ -1 ] [ -q | -Q | -v ] [ -d | -D ] [ -P | -p ] [ -c maxconn ] [ -C localmaxconn ] [ -b backlog ] [ -G gidlist ] [ -g gid ] [ -u uid ] [ -U ] path prog...
-

- -

s6-ipcserver binds a Unix domain socket to path.
It can drop its root privileges.
It closes its stdin and stdout.
For every client connection to this socket, it -forks. The child sets some environment variables, then -executes prog... with stdin reading from the 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-ipcserver 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.

- -

Implementation

- -

s6-ipcserver parses the options and arguments it is given, and -builds a new command line with them. It then executes into that new -command line.
The first program s6-ipcserver executes into is -s6-ipcserver-socketbinder. -It will create and bind a Unix domain socket to path, then -execute into the rest of the command line.
If a privilege-dropping operation has been requested, the -program that s6-ipcserver-socketbinder executes into is -s6-applyuidgid. -It will drop the root privileges, then execute into the rest of the -command line.
The next program in the chain is -s6-ipcserverd. It is executed into -by s6-applyuidgid, or directly by s6-ipcserver-socketbinder if no -privilege-dropping operation has been requested. s6-ipcserverd is -the long-lived process, the "daemon" itself, accepting connections -from clients.
For every client, s6-ipcserverd will spawn an instance of -prog..., the remainder of the command line.

- - -

Options

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-1 : write path, followed by 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.
-q : be quiet.
-Q : be normally verbose. This is the default.
-v : be verbose.
-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.
-P : disable client credentials lookups. The -IPCREMOTEEUID and IPCREMOTEEGID environment variables will be unset -in every instance of prog.... This is the portable option, -because not every system supports credential lookup across Unix domain -sockets; but it is not as secure.
-p : enable client credentials lookups. This -is the default; it works at least on Linux, Solaris, and -*BSD systems. On systems that do not support it, every connection -attempt will fail with a warning message.
-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 user ID. -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-ipcserver'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-ipcserver's groupid -to gid after binding the socket. This is only valid when run -as root.
-u uid : change s6-ipcserver's userid -to uid after binding the socket. This is only valid when run -as root.
-U : change s6-ipcserver'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.

- -

Implementation

- -

s6-ipcserver parses the options and arguments it is given, and -builds a new command line with them. It then executes into that new -command line.
The first program s6-ipcserver executes into is -s6-ipcserver-socketbinder. -It will create and bind a Unix domain socket to path, then -execute into the rest of the command line.
If a privilege-dropping operation has been requested, the -program that s6-ipcserver-socketbinder executes into is -s6-applyuidgid. -It will drop the root privileges, then execute into the rest of the -command line.
The next program in the chain is -s6-ipcserverd. It is executed into -by s6-applyuidgid, or directly by s6-ipcserver-socketbinder if no -privilege-dropping operation has been requested. s6-ipcserverd is -the long-lived process, the "daemon" itself, accepting connections -from clients.
For every client, s6-ipcserverd will spawn an instance of -prog..., the remainder of the command line.

- -

Notes

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s6-ipcserver does not interpret its options itself. It just -dispatches them to the appropriate program on the command line that -it builds.
In previous releases of s6-networking, s6-ipcserver was -monolithic: it did the work of s6-ipcserver-socketbinder, -s6-applyuidgid and s6-ipcserverd 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.

- - - -- cgit v1.2.3

The s6-ipcserver program

Interface

Implementation

Options

Implementation

Notes

The `s6-ipcserver` program