filter: Handle bad filter numbers gracefully.

[paraslash.git] / filter_common.c

diff --git a/filter_common.c b/filter_common.c
index 991b3a1e5a96dc47d7cc6594922883856aeac4d9..b406951e8ff145542e9ad579bde5311b7e3be1aa 100644 (file)
--- a/filter_common.c
+++ b/filter_common.c
@@ -28,15 +28,15 @@
  *
  * \param filter_num Between zero and NUM_SUPPORTED_FILTERS, inclusively.
  *
- * \return Pointer to the filter identified by the given filter number.
+ * \return Pointer to the filter identified by the given filter number, or
+ * NULL if the filter number is out of range.
  *
- * It is a fatal error if the given number is out of range. In this case
- * the function aborts.
+ * \sa filter_name().
  */
 const struct filter *filter_get(int filter_num)
 {
-       assert(filter_num >= 1);
-       assert(filter_num <= LSG_NUM_FILTER_CMD_SUBCOMMANDS);
+       if (filter_num < 1 || filter_num > LSG_NUM_FILTER_CMD_SUBCOMMANDS)
+               return NULL;
        return lls_user_data(FILTER_CMD(filter_num));
 }
 
@@ -45,8 +45,18 @@ static inline bool filter_supported(int filter_num)
        return lls_user_data(FILTER_CMD(filter_num));
 }
 
+/**
+ * Return the name of a filter, given its number.
+ *
+ * \param filter_num See \ref filter_get().
+ *
+ * \return A pointer to a string literal, or NULL if filter_num is out of
+ * range. The caller must not attempt to call free(3) on the returned pointer.
+ */
 const char *filter_name(int filter_num)
 {
+       if (filter_num < 1 || filter_num > LSG_NUM_FILTER_CMD_SUBCOMMANDS)
+               return NULL;
        return lls_command_name(FILTER_CMD(filter_num));
 }