NAME¶

xpaaccess - see if template matches registered XPA access points

SYNOPSIS¶

xpaaccess [-c] [-h] [-i nsinet] [-m method] [-n] [-t sval,lval] [-u users] -v <template> [type]

OPTIONS¶

  -c            contact each access point individually
  -h            print help message
  -i            access XPA point on different machine (override XPA_NSINET)
  -m            override XPA_METHOD environment variable
  -n            return number of matches instead of "yes" or "no"
  -t [s,l]      set short and long timeouts (override XPA_[SHORT,LONG]_TIMEOUT)
  -u [users]    XPA points can be from specified users (override XPA_NSUSERS)
  -v            print info about each successful access point
  -V            print info or error about each access point
  --version     display version and exit

DESCRIPTION¶

xpaaccess returns "yes" to stdout (with a return error code if 1) if there are existing XPA access points that match the template (and optional access type: g,i,s). Otherwise, it returns "no" (with a return error code of 0). If -n is specified, the number of matches is returned instead (both to stdout and in the returned error code). If -v is specified, each access point is displayed to stdout instead of the number of matches.

By default, xpaaccess simply contacts the xpans name server to find the list of registered access points that match the specified template. It also checks to make sure the specified types are supported by that access point. This is the fastest way to determine available access points. However, an access point might registered but not yet available, if, for example, the server program has not entered its event loop to process XPA requests. To find access points that are guaranteed to be available for processing, use the -c (contact) switch. With this switch, xpaaccess contacts each matching XPA server (rather than the name server) to make sure the registered access point really is ready for processing. In this mode, if an access point is registered but not available, xpaaccess will pause for a period of time equal to the XPA_LONG_TIMEOUT, in order to give the server a chance to ready itself. By default, this timeout is 30 seconds. You can shorten the time of delay using the -t "short,long" switch. For example, to shorten the delay time to 2 seconds, use:

  xpaaccess -c -t "2,2" ds9

The first argument is the short delay value, and is ignored in this operation. The second is the long delay timeout.

Note also that the default xpaaccess method (no -c switch) does not check access control (acls) but rather only checks whether the access point is both registered with the xpans name server and provides the specified type of access. In other words, the default xpaaccess could return 'yes' when you might not actually have access. This mode also always returns 'yes' for the xpans name server itself, regardless of whether the name server is active. The -c (contact) switch, which contacts the access point directly, can and does check the access control (only for servers using version 2.1 and above) and also returns the real status of xpans.

SEE ALSO¶

See xpa(n) for a list of XPA help pages