Re-implement $probe_only aspect of f_media_get_TYPE() (where TYPE is cdrom,

nfs, ftp, http, httpproxy, etc.) and f_device_get() (abstract method for
calling aforementioned f_media_get_TYPE()).

Previously, if $probe_only was present and non-NULL, the TYPE functions
would check for $file and exit with an appropriate error status (success if
the file exists and readable, failure otherwise).

While this has been retained, a pair of globals has been introduced:
$PROBE_EXIST and $PROBE_SIZE (see `/usr/share/bsdconfig/media/common.subr')

The $PROBE_EXIST global can be used where you need the functionality of
simply testing for existence (previously the _only_ functionality).

Meanwhile, the new $PROBE_SIZE global can be used to cause the TYPE function
to print the size of the file (in bytes) on standard-out (or -1) if not
found or an error occurs. NOTE: If an error occurs, it is logged with the
dprintf function, which is visible with `-d' flag or debug=1.

In many cases, where you need to get the size of a file _and_ check for its
existence, you can use the return status of a $PROBE_SIZE call.

1 files changed, 8 insertions, 6 deletions

diff --git a/usr.sbin/bsdconfig/share/media/nfs.subr b/usr.sbin/bsdconfig/share/media/nfs.subr
index 93089cb..9ce0467 100644
--- a/usr.sbin/bsdconfig/share/media/nfs.subr
+++ b/usr.sbin/bsdconfig/share/media/nfs.subr
@@ -208,19 +208,21 @@ f_media_init_nfs()
 	return $SUCCESS
 }
 
-# f_media_get_nfs $device $file [$probe_only]
+# f_media_get_nfs $device $file [$probe_type]
 #
 # Returns data from $file on a mounted NFS device. Similar to cat(1). If
-# $probe_only is present and non-NULL, returns success if $file exists.
+# $probe_type is present and non-NULL, returns success if $file exists. If
+# $probe_type is equal to $PROBE_SIZE, prints the size of $file in bytes to
+# standard-out.
 #
 f_media_get_nfs()
 {
-	local dev="$1" file="$2" probe_only="$3"
+	local dev="$1" file="$2" probe_type="$3"
 
-	f_dprintf "f_media_get_nfs: dev=[%s] file=[%s] probe_only=%s" \
-	          "$dev" "$file" "$probe_only"
+	f_dprintf "f_media_get_nfs: dev=[%s] file=[%s] probe_type=%s" \
+	          "$dev" "$file" "$probe_type"
 
-	f_media_generic_get "$MOUNTPOINT" "$file" "$probe_only"
+	f_media_generic_get "$MOUNTPOINT" "$file" "$probe_type"
 }
 
 # f_media_shutdown_nfs $device