Add filename-checking to ignore bad characters

Checking filename so that "--" doesn't become a filename as in the example
below:

sudo ./idlestat --trace -t 10 -f -- rt-app /tmp/browser.json

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/idlestat.c b/idlestat.c
index bba8951..c60f39a 100644
--- a/idlestat.c
+++ b/idlestat.c
@@ -52,6 +52,30 @@
 
 static char buffer[BUFSIZE];
 
+/* I happen to agree with David Wheeler's assertion that Unix filenames
+ * are too flexible. Eliminate some of the madness.
+ * http://www.dwheeler.com/essays/fixing-unix-linux-filenames.html
+ */
+static inline int bad_filename(const char *filename)
+{
+	const char *c;
+
+	c = filename;
+	/* Check for first char being '-' */
+	if (*c == '-') {
+		fprintf(stderr, "Bad character '%c' found in filename\n", *c);
+		return EINVAL;
+	}
+	for (; *c; c++) {
+		/* Check for control chars and other bad characters */
+		if (*c < 32 || *c == '<' || *c == '>' || *c == '|') {
+			fprintf(stderr, "Bad character '%c' found in filename\n", *c);
+			return EINVAL;
+		}
+	}
+	return 0;
+}
+
 static inline int error(const char *str)
 {
 	perror(str);
@@ -1220,6 +1244,10 @@ int getoptions(int argc, char *argv[], struct program_options *options)
 		return -1;
 	}
 
+	if (bad_filename(options->filename)) {
+		return -1;
+	}
+
 	if (options->mode == TRACE) {
 		if (options->duration <= 0) {
 			fprintf(stderr, "expected -t <seconds>\n");