unprotbas: stop allowing 3 filenames.

1 files changed, 4 insertions, 1 deletions

diff --git a/unprotbas.c b/unprotbas.c
index 05a5f6e..c1c0e68 100644
--- a/unprotbas.c
+++ b/unprotbas.c
@@ -811,9 +811,10 @@ void parse_args(int argc, char **argv) {
 				default:  invalid_args(*argv); break;
 			}
 		} else {
+			/* arg doesn't start with a -, must be a filename */
 			if(!input_file)
 				open_input(*argv);
-			else if(!checkonly && !output_file)
+			else if(!checkonly && !output_filename)
 				output_filename = *argv;
 			else
 				invalid_args(*argv);
@@ -890,6 +891,8 @@ int main(int argc, char **argv) {
 		}
 	}
 
+	/* we don't open the output file until all processing is done, to
+		avoid leaving invalid output files if we exit on error. */
 	open_output(output_filename);
 	outbytes = fwrite(data, 1, filelen, output_file);
 	fclose(output_file);