IOPRO_WAIT(8) BSD System Manager's Manual IOPRO_WAIT(8)NAMEiopro_wait - Wait for an IOPRO data port to be configured
SYNOPSIS
/usr/libexec/iopro_wait [-v] [device]
DESCRIPTION
The external units used in the Chase Research IOPRO system may be powered
independently from the host system. When they are powered up ( or at sys-
tem startup time ) they need to be downloaded and configured by the sup-
port daemon ioprod(8) before the data ports are used.
To prevent use before the ports have been configured the data driver will
block open(2) calls on the ports in a similar way to waiting for carrier.
If a non-blocking open is performed then the driver will cancel the open
attempt and return the error code EAGAIN to indicate that the port is
temporarily unavailable.
Most system daemons and programs work well with the above scheme but a
few take the EAGAIN error from a non-blocking open to indicate that the
resource is permanently unavailable and fail.
iopro_wait program is a simple fix for these daemons. Called before the
daemon in question with the name of the device that it is going to use
iopro_wait will block until the port has been configured. The daemon will
then be able to access the device without seeing the error return.
EXAMPLES
For a daemon foobar that uses the port /dev/tty7d the following would re-
place foobar & in the system startup scripts.
(/usr/libexec/iopro_wait /dev/tty7d && foobar) &
DIAGNOSTICS
Should be self explanatory.
You can add warm and fuzzys with the -v flag.
BUGS
Do not place iopro_wait in the system startup scripts in a position where
it could block the starting of ioprod or the system will wait forever.
SEE ALSOioprod(8)open(2)
BSD/OS 28 Jul 95 1