tc: avoid problems with hard coded rate string length

The parse_percent_rate function assumed the buffer was 20 characters.
Better to pass length in case the size ever changes.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/tc/tc_util.c b/tc/tc_util.c
index 1377b536e72fa463c58bb0dcb05a9d69c9f23d7a..4e289ae9c2ade87f6b505f69cb0c9e27a4f7d0a1 100644 (file)
--- a/tc/tc_util.c
+++ b/tc/tc_util.c
@@ -190,7 +190,8 @@ static const struct rate_suffix {
        { NULL }
 };
 
-static int parse_percent_rate(char *rate, const char *str, const char *dev)
+static int parse_percent_rate(char *rate, size_t len,
+                             const char *str, const char *dev)
 {
        long dev_mbit;
        int ret;
@@ -221,8 +222,8 @@ static int parse_percent_rate(char *rate, const char *str, const char *dev)
 
        rate_mbit = perc * dev_mbit;
 
-       ret = snprintf(rate, 20, "%lf", rate_mbit);
-       if (ret <= 0 || ret >= 20) {
+       ret = snprintf(rate, len, "%lf", rate_mbit);
+       if (ret <= 0 || ret >= len) {
                fprintf(stderr, "Unable to parse calculated rate\n");
                return -1;
        }
@@ -239,7 +240,7 @@ int get_percent_rate(unsigned int *rate, const char *str, const char *dev)
 {
        char r_str[20];
 
-       if (parse_percent_rate(r_str, str, dev))
+       if (parse_percent_rate(r_str, sizeof(r_str), str, dev))
                return -1;
 
        return get_rate(rate, r_str);
@@ -249,7 +250,7 @@ int get_percent_rate64(__u64 *rate, const char *str, const char *dev)
 {
        char r_str[20];
 
-       if (parse_percent_rate(r_str, str, dev))
+       if (parse_percent_rate(r_str, sizeof(r_str), str, dev))
                return -1;
 
        return get_rate64(rate, r_str);