unprotbas: don't open output file until ready to write (avoids zero-length output files, on error).

1 files changed, 10 insertions, 7 deletions

diff --git a/unprotbas.c b/unprotbas.c
index 4ed831f..bf8fc76 100644
--- a/unprotbas.c
+++ b/unprotbas.c
@@ -67,6 +67,7 @@ int protect_code = 0;
 /* file handles */
 FILE *input_file = NULL;
 FILE *output_file = NULL;
+char *output_filename = NULL;
 
 void die(const char *msg) {
 	fprintf(stderr, "%s: %s\n", self, msg);
@@ -649,7 +650,7 @@ void open_input(const char *name) {
 }
 
 void open_output(const char *name) {
-	if(!name) {
+	if(!name || (strcmp(name, "-") == 0)) {
 		if(isatty(fileno(stdout))) {
 			die("refusing to write binary data to the terminal");
 		}
@@ -713,8 +714,8 @@ void parse_args(int argc, char **argv) {
 				case 0:
 							 if(!input_file)
 								 open_input(NULL);
-							 else if(!output_file)
-								 open_output(NULL);
+							 else if(!output_filename)
+								 output_filename = *argv;
 							 else
 								 invalid_args(*argv);
 							 break;
@@ -724,14 +725,14 @@ void parse_args(int argc, char **argv) {
 			if(!input_file)
 				open_input(*argv);
 			else if(!checkonly && !output_file)
-				open_output(*argv);
+				output_filename = *argv;
 			else
 				invalid_args(*argv);
 		}
 	}
 
 	if(!input_file) die("no input file given (use - for stdin)");
-	if(!checkonly && !output_file) die("no output file given (use - for stdout)");
+	if(!checkonly && !output_filename) die("no output file given (use - for stdout)");
 	if(keepvars && forcevars) die("-f and -n are mutually exclusive");
 	if(readmap && writemap) die("-r and -w are mutually exclusive");
 	if(readmap && keepvars) die("-r and -n are mutually exclusive (maybe you want -w?)");
@@ -742,6 +743,7 @@ void parse_args(int argc, char **argv) {
 }
 
 int main(int argc, char **argv) {
+	int outbytes;
 	parse_args(argc, argv);
 
 	filelen = readfile();
@@ -798,9 +800,10 @@ int main(int argc, char **argv) {
 		}
 	}
 
-	int got = fwrite(data, 1, filelen, output_file);
+	open_output(output_filename);
+	outbytes = fwrite(data, 1, filelen, output_file);
 	fclose(output_file);
-	if(verbose) fprintf(stderr, "wrote %d bytes\n", got);
+	if(verbose) fprintf(stderr, "wrote %d bytes\n", outbytes);
 
 	if(writemap) write_var_map();