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, 20 insertions, 9 deletions

diff --git a/usr.sbin/bsdconfig/share/media/httpproxy.subr b/usr.sbin/bsdconfig/share/media/httpproxy.subr
index 817cf0d..66e5be4 100644
--- a/usr.sbin/bsdconfig/share/media/httpproxy.subr
+++ b/usr.sbin/bsdconfig/share/media/httpproxy.subr
@@ -329,14 +329,16 @@ f_media_init_http_proxy()
 	return $http_found
 }
 
-# f_media_get_http_proxy $device $file [$probe_only]
+# f_media_get_http_proxy $device $file [$probe_type]
 #
 # Returns data from $file on an FTP server via HTTP proxy using nc(1). Please
 # note that $device is unused but must be present (even if null). Information
-# is instead gathered from the environment. If $probe_only is both present and
+# is instead gathered from the environment. If $probe_type is both present and
 # non-NULL, this function exits after receiving the HTTP header response from
 # the proxy server (if the HTTP response code is 200, success is returned;
-# otherwise failure).
+# otherwise failure). If $probe_type is equal to $PROBE_SIZE, prints the
+# content-length in bytes from the response (or -1 if not found) to standard-
+# out.
 #
 # The variables used to configure the connection are as follows (all of which
 # are configured by f_media_set_http_proxy above):
@@ -358,10 +360,10 @@ f_media_init_http_proxy()
 #
 f_media_get_http_proxy()
 {
-	local dev="$1" file="$2" probe_only="$3" hosts=
+	local dev="$1" file="$2" probe_type="$3" hosts=
 
-	f_dprintf "f_media_get_http_proxy: dev=[%s] file=[%s] probe_only=%s" \
-	          "$dev" "$file" "$probe_only"
+	f_dprintf "f_media_get_http_proxy: dev=[%s] file=[%s] probe_type=%s" \
+	          "$dev" "$file" "$probe_type"
 
 	local proxy_host proxy_port
 	f_getvar $VAR_HTTP_PROXY_HOST proxy_host
@@ -408,7 +410,7 @@ f_media_get_http_proxy()
 		# this is extremely quick'n dirty
 		#
 
-		rv=0
+		rv=0 length=-1
 		while read LINE; do
 			case "$LINE" in
 			HTTP*)
@@ -416,6 +418,12 @@ f_media_get_http_proxy()
 				set -- $LINE; rv=$2
 				f_isinteger "$rv" || rv=0
 				;;
+			"Content-Length: "*)
+				length="${LINE%
}"
+				length="${length#Content-Length: }"
+				f_dprintf "received content-length: %s" \
+				          "$length"
+				;;
 			*)
 				[ "${LINE%
}" ] || break # End of headers
 			esac
@@ -427,14 +435,17 @@ f_media_get_http_proxy()
 		[ $rv -ge 300 ] && exit 3
 		[ $rv -eq 200 ] || exit $FAILURE
 
-		if [ ! "$probe_only" ]; then
+		if [ ! "$probe_type" ]; then
 			cat # output the rest ``as-is''
+		elif [ "$probe_type" = "$PROBE_SIZE" ]; then
+			f_isinteger "$length" || length=-1
+			echo "$length"
 		fi
 		exit 200
 	)
 	local retval=$?
 	[ $retval -eq 200 ] && return $SUCCESS
-	[ "$probe_only" ] && return $FAILURE
+	[ "$probe_type" ] && return $FAILURE
 
 	case "$retval" in
 	  5) f_show_msg "$msg_server_error_when_requesting_url" "$url" ;;