1 files changed, 123 insertions, 0 deletions
diff --git a/src/usermap.c b/src/usermap.c
new file mode 100644
index 0000000..b900296
--- /dev/null
+++ b/src/usermap.c
@@ -0,0 +1,123 @@
+
+#include "usermap.h"
+#include "userinfo.h"
+#include <stdlib.h>
+
+struct UserMap {
+    uid_t *user_from;
+    uid_t *user_to;
+    gid_t *group_from;
+    gid_t *group_to;
+    int user_capacity;
+    int group_capacity;
+    int user_size;
+    int group_size;
+};
+
+UserMap *usermap_create()
+{
+    UserMap* map = (UserMap*)malloc(sizeof(UserMap));
+    map->user_from = NULL;
+    map->user_to = NULL;
+    map->group_from = NULL;
+    map->group_to = NULL;
+    map->user_capacity = 0;
+    map->group_capacity = 0;
+    map->user_size = 0;
+    map->group_size = 0;
+    return map;
+}
+
+void usermap_destroy(UserMap *map)
+{
+    free(map->user_from);
+    free(map->user_to);
+    free(map->group_from);
+    free(map->group_to);
+    free(map);
+}
+
+UsermapStatus usermap_add_uid(UserMap *map, uid_t from, uid_t to)
+{
+    int i;
+    if (from == to) {
+        return usermap_status_ok;
+    }
+    if (map->user_size == map->user_capacity) {
+        map->user_capacity *= 2;
+        map->user_from = (uid_t*)realloc(map->user_from, map->user_capacity * sizeof(uid_t));
+        map->user_to = (uid_t*)realloc(map->user_to, map->user_capacity * sizeof(uid_t));
+    }
+    if (usermap_get_uid(map, from) != from) {
+        return usermap_status_duplicate_key;
+    }
+    i = map->user_size;
+    map->user_from[i] = from;
+    map->user_to[i] = to;
+    map->user_size += 1;
+    return usermap_status_ok;
+}
+
+UsermapStatus usermap_add_gid(UserMap *map, gid_t from, gid_t to)
+{
+    int i;
+    if (from == to) {
+        return usermap_status_ok;
+    }
+    if (map->group_size == map->group_capacity) {
+        map->group_capacity *= 2;
+        map->group_from = (gid_t*)realloc(map->group_from, map->group_capacity * sizeof(gid_t));
+        map->group_to = (gid_t*)realloc(map->group_to, map->group_capacity * sizeof(gid_t));
+    }
+    if (usermap_get_gid(map, from) != from) {
+        return usermap_status_duplicate_key;
+    }
+    i = map->group_size;
+    map->group_from[i] = from;
+    map->group_to[i] = to;
+    map->group_size += 1;
+    return usermap_status_ok;
+}
+
+const char* usermap_errorstr(UsermapStatus status)
+{
+    switch (status) {
+        case usermap_status_ok: return "ok";
+        case usermap_status_duplicate_key: return "user mapped twice";
+        default: return "unknown error";
+    }
+}
+
+uid_t usermap_get_uid(UserMap *map, uid_t u)
+{
+    uid_t result = usermap_get_uid_or_none(map, u);
+    return (result != -1 ? result : u);
+}
+
+gid_t usermap_get_gid(UserMap *map, gid_t g)
+{
+    gid_t result = usermap_get_gid_or_none(map, g);
+    return (result != -1 ? result : g);
+}
+
+uid_t usermap_get_uid_or_none(UserMap *map, uid_t u)
+{
+    int i;
+    for (i = 0; i < map->user_size; ++i) {
+        if (map->user_from[i] == u) {
+            return map->user_to[i];
+        }
+    }
+    return -1;
+}
+
+gid_t usermap_get_gid_or_none(UserMap *map, gid_t g)
+{
+    int i;
+    for (i = 0; i < map->group_size; ++i) {
+        if (map->group_from[i] == g) {
+            return map->group_to[i];
+        }
+    }
+    return -1;
+}