10.0;xsubs (execute_subsystem), revision 1.0, 88/01/21
xsubs (execute_subsystem) -- Run Shell script subsystem manager.
usage: xsubs pathname [args...]
DESCRIPTION
Once a protected subsystem, a subsystem manager(s), and a subsystem data
object(s) exist, any user can execute the manager program. To run a
binary manager program, simply execute the program. To run a shell-
script manager program, you must use the xsubs command. Note that in
order to see the name of a subsystem created on another node, you must
copy the file /sys/subsys/subsystem_name to your node. If you do not
copy this file, you can use the subsystem managers to operate on the
objects, but when you ask to display the name of the subsystem, you get
an error message like the following:
$ subs //fred/jtj/com/top_secret
?(subs) Can't show subsystem manager type
for "//fred/jtj/com/top_secret"
- subsystem name not found (US/aclm)
$
ARGUMENTS
pathname (required)
Specify shell script containing the subsystem manager to be
executed. Note that this script must contain the commands subs
-up and subs -down in order to enter and exit the subsystem.
args ... (optional)
Specify arguments to be passed to the shell script.
Default if omitted: no arguments passed
EXAMPLES
Suppose you have an append-only list that you wish to protect. Anyone
can read the list, and append to the list, but no one can overwrite
existing contents. Assume that the subsystem append_only already exists.
Then the app shell script, which appends standard input to an append-only
file, looks like this:
# app --- append to an append_only file
subs -up
catf >>^1 # append to the file passed as first argument
subs -down
To make app a manager of the append_only subsystem, enter
$ensubs append_only # enter subsystem
subs app append_only -mgr
*** EOF ****
A run of app looks like this:
$xsubs app aofile # execute app on aofile
this is the stuff that is appended
*** EOF ***
SEE ALSO
More information is available. Type
help protected_subsystems
For a list of shell commands for use with protected
subsystems
help protection protected_subsystems
For a detailed description of protected subsystems