+typedef struct unsigned_to_name_map_t {
+ unsigned id;
+ char name[12];
+} unsigned_to_name_map_t;
+
+typedef struct cache_t {
+ unsigned_to_name_map_t *cache;
+ int size;
+} cache_t;
+
+static cache_t username, groupname;
+
+static void clear_cache(cache_t *cp)
+{
+ free(cp->cache);
+ cp->cache = NULL;
+ cp->size = 0;
+}
+void clear_username_cache(void)
+{
+ clear_cache(&username);
+ clear_cache(&groupname);
+}
+
+#if 0 /* more generic, but we don't need that yet */
+/* Returns -N-1 if not found. */
+/* cp->cache[N] is allocated and must be filled in this case */
+static int get_cached(cache_t *cp, unsigned id)
+{
+ int i;
+ for (i = 0; i < cp->size; i++)
+ if (cp->cache[i].id == id)
+ return i;
+ i = cp->size++;
+ cp->cache = xrealloc(cp->cache, cp->size * sizeof(*cp->cache));
+ cp->cache[i++].id = id;
+ return -i;
+}
+#endif
+
+typedef char* ug_func(char *name, long uid, int bufsize);
+static char* get_cached(cache_t *cp, unsigned id, ug_func* fp)
+{
+ int i;
+ for (i = 0; i < cp->size; i++)
+ if (cp->cache[i].id == id)
+ return cp->cache[i].name;
+ i = cp->size++;
+ cp->cache = xrealloc(cp->cache, cp->size * sizeof(*cp->cache));
+ cp->cache[i].id = id;
+ fp(cp->cache[i].name, id, sizeof(cp->cache[i].name));
+ return cp->cache[i].name;
+}
+const char* get_cached_username(uid_t uid)
+{
+ return get_cached(&username, uid, bb_getpwuid);
+}
+const char* get_cached_groupname(gid_t gid)
+{
+ return get_cached(&groupname, gid, bb_getgrgid);
+}
+
+