[update] asctime_r return value.

components/libc/compilers/common/time.c

@@ -239,8 +239,28 @@ RTM_EXPORT(mktime);
 
 char* asctime_r(const struct tm *t, char *buf)
 {
-    RT_ASSERT(rt_strlen(days) > (t->tm_wday << 2));
-    RT_ASSERT(rt_strlen(months) > (t->tm_mon << 2));
+    /* Checking input validity */
+    if (rt_strlen(days) <= (t->tm_wday << 2) || rt_strlen(months) <= (t->tm_mon << 2))
+    {
+        LOG_W("The input exceeded the limit, please check it.");
+        *(int*) buf = *(int*) days;
+        *(int*) (buf + 4) = *(int*) months;
+        num2str(buf + 8, t->tm_mday);
+        if (buf[8] == '0')
+            buf[8] = ' ';
+        buf[10] = ' ';
+        num2str(buf + 11, t->tm_hour);
+        buf[13] = ':';
+        num2str(buf + 14, t->tm_min);
+        buf[16] = ':';
+        num2str(buf + 17, t->tm_sec);
+        buf[19] = ' ';
+        num2str(buf + 20, 2000 / 100);
+        num2str(buf + 22, 2000 % 100);
+        buf[24] = '\n';
+        buf[25] = '\0';
+        return buf;
+    }
 
     /* "Wed Jun 30 21:49:08 1993\n" */
     *(int*) buf = *(int*) (days + (t->tm_wday << 2));