unalf: Error checking for -n option.

2 files changed, 29 insertions, 3 deletions

diff --git a/TODO.txt b/TODO.txt
index 5b0b9d9..48ec376 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,5 +1,3 @@
-- error checking for unalf -n (dup option, bad #, wildcards)
-
 - maybe: alf foo.alf unix.filename=ATARI.NAM  ...unalf could use this too.
 
 - fuzz alf and unalf with afl++ or similar. this is a work in progress,
diff --git a/src/opts.c b/src/opts.c
index 06ad9dc..861ef2b 100644
--- a/src/opts.c
+++ b/src/opts.c
@@ -26,7 +26,30 @@ static void show_globs(void) {
 #endif
 
 int parsenum(const char opt, const char *arg) {
-	return atoi(arg); /* TODO: use strtol(), die on error */
+	const char *p = arg;
+	int result, err = 0;
+
+	if(opts.extract_num) {
+		fprintf(stderr, "%s: fatal: can't use multiple -%c arguments (try --help).\n", self, opt);
+		exit(1);
+	}
+
+	for(p = arg; *p && (*p >= '0' && *p <= '9'); p++)
+		;
+
+	if(*p || p == arg) {
+		err++;
+	} else {
+		result = atoi(arg);
+		if(!result) err++;
+	}
+
+	if(err) {
+		fprintf(stderr, "%s: fatal: invalid number '%s' for -%c option (try --help).\n", self, arg, opt);
+		exit(1);
+	}
+
+	return result;
 }
 
 void parse_opts(int argc, char * const *argv) {
@@ -72,6 +95,11 @@ void parse_opts(int argc, char * const *argv) {
 		include_globs = &argv[optind + 1]; /* might be null, that's OK */
 
 	ig = (char **)include_globs;
+	if(opts.extract_num && *ig) {
+		fprintf(stderr, "%s: fatal: can't use wildcards with -n (try -h or --help)\n.", self);
+		exit(1);
+	}
+
 	while(*ig) {
 		if(globmatch("*.alf", *ig)) {
 			fprintf(stderr, "%s: ALF files don't normally contain other ALF files, are you trying to extract/list multiple ALF files at once?\n", self);