Use strncpy_or_assert to copy pilot name into rec

Author: Nopey

src/game/scenes/arena.c

@@ -34,6 +34,7 @@
 #include "utils/allocator.h"
 #include "utils/log.h"
 #include "utils/random.h"
+#include "utils/c_string_util.h"
 #include "video/video.h"
 
 #define TEXT_COLOR 0xC7
@@ -1538,9 +1539,7 @@ int arena_create(scene *scene) {
             local->rec->pilots[i].info.color_1 = player->pilot->color_1;
             local->rec->pilots[i].info.color_2 = player->pilot->color_2;
             local->rec->pilots[i].info.color_3 = player->pilot->color_3;
-            // XXX ugly strncpy, implicit truncation, no nul termination guarantee, why are we even copying the pilot's
-            // name in here?
-            strncpy(local->rec->pilots[i].info.name, lang_get_offset(LangPilot, player->pilot->pilot_id), 18);
+            strncpy_or_assert(local->rec->pilots[i].info.name, lang_get_offset(LangPilot, player->pilot->pilot_id), 18);
         }
         local->rec->arena_id = scene->id - SCENE_ARENA0;
     } else {

src/utils/c_string_util.c

@@ -10,6 +10,14 @@ char *strncpy_or_truncate(char *dest, const char *src, size_t n) {
     return ret;
 }
 
+char *strncpy_or_assert(char *dest, const char *src, size_t n) {
+    char *ret = strncpy(dest, src, n);
+    assert(ret[n - 1] == '\0' || !"truncating in strncpy!");
+    if(n > 0)
+        dest[n - 1] = '\0';
+    return ret;
+}
+
 char *omf_strdup_real(char const *s, char const *file, int line) {
     assert(s != NULL);
     size_t valid_range = strlen(s) + 1;

src/utils/c_string_util.h

@@ -6,6 +6,9 @@
 // strncpy() that guarantees null-termination.
 char *strncpy_or_truncate(char *dest, const char *src, size_t n);
 
+// strncpy() that guarantees null-termination, and asserts when truncating.
+char *strncpy_or_assert(char *dest, const char *src, size_t n);
+
 // strdup() that uses our allocator
 char *omf_strdup_real(char const *s, char const *file, int line);
 #define omf_strdup(s) omf_strdup_real((s), __FILE__, __LINE__)