A-Shell Development History

The file hook mechanism (this is an early beta release) allows you to establish file "hooks" on specific files and file events. The "hook" is an SBX which is called automatically by A-Shell when the specified event occurs on the file. The SBX may then output auditing information, check for anomalies, enforce rules, export data, essentially whatever it likes.

To establish a hook on a file:

++include ashinc:ashell.def

++include ashinc:hook.def

xcall miamex, MX_FILEHOOK, op, status, file {,fid, handler, events, flags}

Parameters

op  (Num)  [in]

may be one of the following (defined in hook.def):

 

status  (Signed Num)  [out]

returns status code:

 

file  (String)  [in]

is the specification of the file whose operations are to be hooked. (Only AMOS-compatible filespecs are currently suported.) Note that with OPs 0, 1 and 3, FILE$ may be "*" to perform the operation on all the hooks in the hook table.

fid  (Num)  [in]

a unique integer identifier for the file, which will be used in any output files to reference the file (more compact than outputting the file spec each time.)

handler  (String)  [in]

depends on the OP. For OP 2 (add), it must specify the handler for the hook, using the following syntax:

SBX:xxxxxx

where xxxxxx is the name of an SBX file, which will be called to process the hook. (see "HOOK SBX SPECIFICATION" below for further details. Note that additional handler types (and corresponding syntax), such as a text file, FIFO, or TCP connection, may be defined later.

For OP 6 (HOOKOP_APPEVENT), the handler parameter may be used to pass an arbitrary string to the hook routine. Typically this may be used to include a message in the hook log file, such as "posting run complete".

events  (B4)  [in]

a bit-field of events to hook, from the following (defined in hook.def):

 

flags  (B4)  [in]

a bit-field of flags which are passed to the hook routine (as a clue to how the hook should operate, and/or which are used by A-Shell to modify the operation of the hook (from hook.def):