diff --git a/config.mk b/config.mk
index 00e8f62..1b7180d 100644
--- a/config.mk
+++ b/config.mk
@@ -47,4 +47,4 @@ VERBOSE ?= 0
 
 # database
 # possible values are sqlite and plain
-DATABASE ?= sqlite
+DATABASE ?= plain
diff --git a/database-plain.c b/database-plain.c
index 65ab6e6..4fb8c2a 100644
--- a/database-plain.c
+++ b/database-plain.c
@@ -1,30 +1,160 @@
 /* See LICENSE file for license and copyright information */
 
-#include <glib.h>
 #include <girara.h>
+#include <glib.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <sched.h>
 
 #include "database.h"
 
+typedef struct zathura_lock_s
+{
+  int sock;
+  struct sockaddr_un sun;
+} zathura_lock_t;
+
+#define BOOKMARKS "bookmarks"
+#define HISTORY "history"
+
+/* forward declaration */
+static zathura_lock_t* zathura_lock_new(const char* name);
+static void zathura_lock_free(zathura_lock_t* lock);
+static void zathura_lock_lock(zathura_lock_t* lock);
+static void zathura_lock_unlock(zathura_lock_t* lock);
+static bool zathura_db_check_file(const char* path);
+static girara_list_t* zathura_db_read_bookmarks_from_file(char* path);
+static girara_list_t* zathura_db_read_history_from_file(char* path);
+
 struct zathura_database_s
 {
-  void* tmp;
+  char* bookmark_path;
+  zathura_lock_t* bookmark_lock;
+  girara_list_t* bookmarks;
+  GFileMonitor* bookmark_monitor;
+
+  char* history_path;
+  zathura_lock_t* history_lock;
+  girara_list_t* history;
+  GFileMonitor* history_monitor;
 };
 
 zathura_database_t*
 zathura_db_init(const char* dir)
 {
+  if (dir == NULL) {
+    goto error_ret;
+  }
+
+  zathura_database_t* db = calloc(1, sizeof(zathura_database_t));
+  if (db == NULL) {
+    goto error_ret;
+  }
+
+  /* bookmarks */
+  db->bookmark_path = g_build_filename(dir, BOOKMARKS, NULL);
+  if (db->bookmark_path == NULL ||
+      zathura_db_check_file(db->bookmark_path) == false) {
+    goto error_free;
+  }
+
+  db->bookmark_lock = zathura_lock_new("zathura-bookmarks");
+  if (db->bookmark_lock == NULL) {
+    goto error_free;
+  }
+
+  GFile* bookmark_file = g_file_new_for_path(db->bookmark_path);
+  if (bookmark_file != NULL) {
+    db->bookmark_monitor = g_file_monitor(bookmark_file, G_FILE_MONITOR_NONE, NULL, NULL);
+  } else {
+    goto error_free;
+  }
+  g_object_unref(bookmark_file);
+
+  db->bookmarks = zathura_db_read_bookmarks_from_file(db->bookmark_path);
+  if (db->bookmarks == NULL) {
+    goto error_free;
+  }
+
+  /* history */
+  db->history_path = g_build_filename(dir, HISTORY, NULL);
+  if (db->history_path == NULL ||
+      zathura_db_check_file(db->history_path) == false) {
+    goto error_free;
+  }
+
+  db->history_lock = zathura_lock_new("zathura-history");
+  if (db->history_lock == NULL) {
+    goto error_free;
+  }
+
+  GFile* history_file = g_file_new_for_path(db->history_path);
+  if (history_file != NULL) {
+    db->history_monitor = g_file_monitor(history_file, G_FILE_MONITOR_NONE, NULL, NULL);
+  } else {
+    goto error_free;
+  }
+  g_object_unref(history_file);
+
+  db->history = zathura_db_read_history_from_file(db->history_path);
+  if (db->history == NULL) {
+    goto error_free;
+  }
+
+  return db;
+
+error_free:
+
+  zathura_db_free(db);
+
+error_ret:
+
   return NULL;
 }
 
 void
 zathura_db_free(zathura_database_t* db)
 {
+  if (db == NULL) {
+    return;
+  }
+
+  /* bookmarks */
+  g_free(db->bookmark_path);
+  zathura_lock_free(db->bookmark_lock);
+
+  if (db->bookmark_monitor != NULL) {
+    g_object_unref(db->bookmark_monitor);
+  }
+
+  girara_list_free(db->bookmarks);
+
+  /* history */
+  g_free(db->history_path);
+  zathura_lock_free(db->history_lock);
+
+  if (db->history_monitor != NULL) {
+    g_object_unref(db->history_monitor);
+  }
+
+  girara_list_free(db->history);
+
+  /* database */
+  free(db);
 }
 
 bool
 zathura_db_add_bookmark(zathura_database_t* db, const char* file,
     zathura_bookmark_t* bookmark)
 {
+  if (db == NULL || file == NULL || bookmark == NULL) {
+    return false;
+  }
+
   return false;
 }
 
@@ -32,12 +162,20 @@ bool
 zathura_db_remove_bookmark(zathura_database_t* db, const char* file, const char*
     id)
 {
+  if (db == NULL || file == NULL || id == NULL) {
+    return false;
+  }
+
   return false;
 }
 
 girara_list_t*
 zathura_db_load_bookmarks(zathura_database_t* db, const char* file)
 {
+  if (db == NULL || file == NULL) {
+    return NULL;
+  }
+
   return NULL;
 }
 
@@ -45,6 +183,10 @@ bool
 zathura_db_set_fileinfo(zathura_database_t* db, const char* file, unsigned int
     page, int offset, float scale)
 {
+  if (db == NULL || file == NULL) {
+    return NULL;
+  }
+
   return false;
 }
 
@@ -52,5 +194,107 @@ bool
 zathura_db_get_fileinfo(zathura_database_t* db, const char* file, unsigned int*
     page, int* offset, float* scale)
 {
+  if (db == NULL || file == NULL || page == NULL || offset == NULL || scale == NULL) {
+    return false;
+  }
+
   return false;
 }
+
+static zathura_lock_t*
+zathura_lock_new(const char* name)
+{
+  if (name == NULL) {
+    return NULL;
+  }
+
+  zathura_lock_t* lock = calloc(1, sizeof(zathura_lock_t));
+  if (lock == NULL) {
+    return NULL;
+  }
+
+  strncpy(&(lock->sun).sun_path[1], name, sizeof(lock->sun.sun_path) - 2);
+  lock->sun.sun_family = AF_UNIX;
+
+  if ((lock->sock = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0) {
+    free(lock);
+    return NULL;
+  }
+
+  return lock;
+}
+
+static void
+zathura_lock_free(zathura_lock_t* lock)
+{
+  if (lock == NULL) {
+    return;
+  }
+
+  close(lock->sock);
+  free(lock);
+}
+
+static void
+zathura_lock_lock(zathura_lock_t* lock)
+{
+  if (lock == NULL) {
+    return;
+  }
+
+  while (bind(lock->sock, (struct sockaddr*) &(lock->sun), sizeof(lock->sun)) < 0) {
+    sched_yield();
+  }
+}
+
+static void
+zathura_lock_unlock(zathura_lock_t* lock)
+{
+  if (lock == NULL) {
+    return;
+  }
+
+  close(lock->sock);
+  lock->sock = socket(PF_UNIX, SOCK_DGRAM, 0);
+}
+
+static bool
+zathura_db_check_file(const char* path)
+{
+  if (path == NULL) {
+    return false;
+  }
+
+  if (g_file_test(path, G_FILE_TEST_EXISTS) == false) {
+    FILE* file = fopen(path, "w");
+    if (file != NULL) {
+      fclose(file);
+    } else {
+      return false;
+    }
+  } else if (g_file_test(path, G_FILE_TEST_IS_REGULAR) == false) {
+    return false;
+  }
+
+  return true;
+}
+
+static girara_list_t*
+zathura_db_read_bookmarks_from_file(char* path)
+{
+  if (path == NULL) {
+    return NULL;
+  }
+
+  return NULL;
+}
+
+static girara_list_t*
+zathura_db_read_history_from_file(char* path)
+{
+  if (path == NULL) {
+    return NULL;
+  }
+
+  return NULL;
+}