.TH apphub 8

'''

.SH NAME

\fBapphub\fR \- generic application supervisor

'''

.SH DESCRIPTION

This service spawns applications on user's request. It is meant primarily

for GUI applications, but can handle pretty much anything that does not

require user input from stdin or open TTY on stdout.

.P

\fBapphub\fR is a regular service that should be started during system boot.

'''

.SH USAGE

Applications to be spawned by \fBapphub\fR are defined by executable files

in /etc/apphub/. The base name of the file is what needs to be passed to

\fBappctl\fR in order to spawn the script. When commanded to do so,

\fBapphub\fR execs the script in a newly spawned process.

.P

Sample script, /etc/apphub/foo:

.P

.ni

#!/sbin/msh

setenv PATH /usr/bin

setuid foo:apps

invoke /usr/bin/xbigapp

.fi

.P

Application defined by this script can them be started using

.P

.ni

appctl start foo

.fi

.P

Spawned applications get their arguments and environment from \fBappctl\fR.

.P

The scripts inherit credentials from the parent \fBapphub\fR process, which

typically means root uid and full capabilities. It is up to the script to limit

capabilities, set uid and groups, and otherwise set up process environment.

.P

Applications are expected to not take any input from stdin, and to not output

anything to either stdout or stderr during normal operations. In the spawned

process, all three standard file descriptors (0, 1, 2) point to the write end

of a pipe; \fBapphub\fR reads the other end of the pipe into a ring buffer,

and lets the user inspect its contents. The collected output is only meant to

be used for troubleshooting misbehaving applications, it is not supposed to be

a part of normal operations.

.P

The name of the script may be chosen arbitrarily. It is perfectly fine to have

several scripts exec the same executable, possibly with different options or

environment settings.

.P

Applications may exit at will, and generally are expected to do so.

'''

.SH FILES

.IP "/run/ctrl/apphub" 4

Control socket.

.IP "/etc/apphub" 4

Configuration directory.

'''

.SH SEE ALSO

\fBappctl\fR(1).