[uri] Decode/encode URIs when parsing/unparsing

Currently, handling of URI escapes is ad-hoc; escaped strings are
stored as-is in the URI structure, and it is up to the individual
protocol to unescape as necessary. This is error-prone and expensive
in terms of code size. Modify this behavior by unescaping in
parse_uri() and escaping in unparse_uri() those fields that typically
handle URI escapes (hostname, user, password, path, query, fragment),
and allowing unparse_uri() to accept a subset of fields to print so
it can be easily used to generate e.g. the escaped HTTP path?query
request.

Signed-off-by: Joshua Oreman <oremanj@rwcr.net>
Signed-off-by: Marty Connor <mdc@etherboot.org>

src/usr/autoboot.c

@@ -61,7 +61,9 @@ int boot_next_server_and_filename ( struct in_addr next_server,
 				    const char *filename ) {
 	struct uri *uri;
 	struct image *image;
-	char buf[ 23 /* tftp://xxx.xxx.xxx.xxx/ */ + strlen(filename) + 1 ];
+	char buf[ 23 /* tftp://xxx.xxx.xxx.xxx/ */ +
+		  ( 3 * strlen(filename) ) /* completely URI-encoded */
+		  + 1 /* NUL */ ];
 	int filename_is_absolute;
 	int rc;
 
@@ -78,8 +80,10 @@ int boot_next_server_and_filename ( struct in_addr next_server,
 		 * between filenames with and without initial slashes,
 		 * which is significant for TFTP.
 		 */
-		snprintf ( buf, sizeof ( buf ), "tftp://%s/%s",
-			   inet_ntoa ( next_server ), filename );
+		snprintf ( buf, sizeof ( buf ), "tftp://%s/",
+			   inet_ntoa ( next_server ) );
+		uri_encode ( filename, buf + strlen ( buf ),
+			     sizeof ( buf ) - strlen ( buf ), URI_PATH );
 		filename = buf;
 	}
 

src/usr/imgmgmt.c

@@ -61,7 +61,7 @@ int imgfetch ( struct image *image, const char *uri_string,
 	if ( password )
 		uri->password = "***";
 	unparse_uri ( uri_string_redacted, sizeof ( uri_string_redacted ),
-		      uri );
+		      uri, URI_ALL );
 	uri->password = password;
 
 	if ( ( rc = create_downloader ( &monojob, image, image_register,