diff --git a/CMakeLists.txt b/CMakeLists.txt
index 379b33b..6a9597e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,7 +29,7 @@ option(BUILD_TESTING "Build tests" OFF)
 
 add_executable(${APP_NAME}
     ${SOURCE_DIR}/wm.c
-    ${SOURCE_DIR}/utils.c
+    ${SOURCE_DIR}/base/log.c
     ${SOURCE_DIR}/buffer.c
     ${SOURCE_DIR}/backtrace.c
     ${SOURCE_DIR}/monitor.c
diff --git a/src/backend/output_utils.c b/src/backend/output_utils.c
index 30a798a..d2abd8d 100644
--- a/src/backend/output_utils.c
+++ b/src/backend/output_utils.c
@@ -3,9 +3,9 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "base/memory.h"
 #include "core/backend.h"
 #include "core/types.h"
-#include "utils.h"
 
 static inline int32_t right(rect_t a) { return a.x + a.width; }
 static inline int32_t bottom(rect_t a) { return a.y + a.height; }
diff --git a/src/backend/x11/backend.c b/src/backend/x11/backend.c
index ae5dc9f..be25fb3 100644
--- a/src/backend/x11/backend.c
+++ b/src/backend/x11/backend.c
@@ -12,8 +12,9 @@
 #include <xcb/xproto.h>
 
 #include "backend/output_utils.h"
+#include "base/log.h"
+#include "base/memory.h"
 #include "core/types.h"
-#include "utils.h"
 
 struct backend_t {
   xcb_connection_t *conn;
diff --git a/src/utils.c b/src/base/log.c
similarity index 89%
rename from src/utils.c
rename to src/base/log.c
index d64f68f..bc5a667 100644
--- a/src/utils.c
+++ b/src/base/log.c
@@ -1,4 +1,4 @@
-#include "utils.h"
+#include "base/log.h"
 
 #include <stdarg.h>
 #include <stdio.h>
@@ -19,9 +19,6 @@ const char *current_time_str(void) {
   return buffer;
 }
 
-/**
- * Print error and exit with EXIT_FAILURE code.
- */
 void _fatal(int line, const char *fct, const char *file, const char *fmt, ...) {
   va_list ap;
 
@@ -34,9 +31,6 @@ void _fatal(int line, const char *fct, const char *file, const char *fmt, ...) {
   exit(EXIT_FAILURE);
 }
 
-/**
- * Print error message on stderr
- */
 void _warn(int line, const char *fct, const char *file, const char *fmt, ...) {
   va_list ap;
 
diff --git a/src/base/log.h b/src/base/log.h
new file mode 100644
index 0000000..af5ff3f
--- /dev/null
+++ b/src/base/log.h
@@ -0,0 +1,32 @@
+#pragma once
+
+#include <stdarg.h>
+#include <stdio.h>
+
+#define fatal(format, ...) \
+  _fatal(__LINE__, __FUNCTION__, __FILE__, format, ##__VA_ARGS__)
+void _fatal(int line, const char *function, const char *file,
+            const char *format, ...) __attribute__((noreturn))
+__attribute__((format(printf, 4, 5)));
+
+#define warn(format, ...) \
+  _warn(__LINE__, __FUNCTION__, __FILE__, format, ##__VA_ARGS__)
+void _warn(int line, const char *function, const char *file, const char *format,
+           ...) __attribute__((format(printf, 4, 5)));
+
+const char *current_time_str(void);
+
+#if defined(RELEASE)
+#define logger(format, ...)
+#elif defined(LOG_FILE)
+static inline void logger(const char *format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  FILE *log_file = fopen(LOG_FILE, "a+t");
+  vfprintf(log_file, format, ap);
+  va_end(ap);
+  fclose(log_file);
+}
+#else
+#define logger(format, ...) printf(format, ##__VA_ARGS__)
+#endif
diff --git a/src/base/macros.h b/src/base/macros.h
new file mode 100644
index 0000000..2ae2e8d
--- /dev/null
+++ b/src/base/macros.h
@@ -0,0 +1,29 @@
+#pragma once
+
+#include <stddef.h>
+#include <sys/types.h>
+
+#define ssizeof(foo) (ssize_t)sizeof(foo)
+#define countof(foo) (ssizeof(foo) / ssizeof(foo[0]))
+
+#ifdef __GNUC__
+#define likely(expr) __builtin_expect(!!(expr), 1)
+#define unlikely(expr) __builtin_expect((expr), 0)
+#else
+#define likely(expr) expr
+#define unlikely(expr) expr
+#endif
+
+#ifdef MIN
+#undef MIN
+#endif
+#ifndef MIN
+#define MIN(a, b) (((a) < (b)) ? (a) : (b))
+#endif
+
+#ifdef MAX
+#undef MAX
+#endif
+#ifndef MAX
+#define MAX(a, b) (((a) > (b)) ? (a) : (b))
+#endif
diff --git a/src/base/memory.h b/src/base/memory.h
new file mode 100644
index 0000000..705d1da
--- /dev/null
+++ b/src/base/memory.h
@@ -0,0 +1,73 @@
+#pragma once
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include "base/macros.h"
+
+#define p_alloc_nr(x) (((x) + 16) * 3 / 2)
+#define p_new(type, count) ((type *)xmalloc(sizeof(type) * (count)))
+#define p_clear(p, count) ((void)memset((p), 0, sizeof(*(p)) * (count)))
+#define p_realloc(pp, count) xrealloc((void *)(pp), sizeof(**(pp)) * (count))
+#define p_copy(src, count) xmemcopy((src), sizeof(*(src)) * (count))
+
+#define p_delete(mem_p)              \
+  do {                               \
+    void **__ptr = (void **)(mem_p); \
+    free(*__ptr);                    \
+    *(void **)__ptr = nullptr;       \
+  } while (0)
+
+static inline char *p_strdup(const char *text) {
+  char *r = strdup(text);
+  if (!r) abort();
+  return r;
+}
+
+static inline char *p_strdup_nullable(const char *text) {
+  if (!text) return nullptr;
+  return p_strdup(text);
+}
+
+static inline void *__attribute__((malloc)) xmalloc(ssize_t size) {
+  void *ptr;
+
+  if (size <= 0) return nullptr;
+
+  ptr = calloc(1, size);
+
+  if (!ptr) abort();
+
+  return ptr;
+}
+
+static inline void *xmemcopy(const void *src, size_t n) {
+  if (!n) return nullptr;
+
+  void *mem = xmalloc(n);
+  void *ret = memcpy(mem, src, n);
+  if (ret != mem) abort();
+  return ret;
+}
+
+static inline void xrealloc(void **ptr, ssize_t newsize) {
+  if (newsize <= 0)
+    p_delete(ptr);
+  else {
+    *ptr = realloc(*ptr, newsize);
+    if (!*ptr) abort();
+  }
+}
+
+/*
+ * Unlike strlen(), a_strlen() accepts nullptr and returns 0 in that case.
+ */
+static inline ssize_t a_strlen(const char *s) { return s ? strlen(s) : 0; }
+
+static constexpr size_t INIT_CAPACITY = 4;
+static inline size_t next_capacity(size_t capacity) {
+  if (capacity) return capacity * 2;
+  return INIT_CAPACITY;
+}
diff --git a/src/config/loader.c b/src/config/loader.c
index ec07854..7eb7c70 100644
--- a/src/config/loader.c
+++ b/src/config/loader.c
@@ -4,7 +4,8 @@
 #include <stdlib.h>
 #include <unistd.h>
 
-#include "utils.h"
+#include "base/log.h"
+#include "base/memory.h"
 
 static char *config_loader_join_path(const char *base, const char *suffix) {
   if (!base || !suffix) return nullptr;
diff --git a/src/core/layout.c b/src/core/layout.c
index 535e64d..0561a47 100644
--- a/src/core/layout.c
+++ b/src/core/layout.c
@@ -4,7 +4,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "utils.h"
+#include "base/memory.h"
 
 void layout_result_init(layout_result_t *result) {
   result->item_count = 0;
diff --git a/src/core/runtime.c b/src/core/runtime.c
index 1943eb9..2815d0f 100644
--- a/src/core/runtime.c
+++ b/src/core/runtime.c
@@ -2,10 +2,10 @@
 
 #include <stddef.h>
 
+#include "base/memory.h"
 #include "core/backend.h"
 #include "core/state.h"
 #include "core/wm_desc.h"
-#include "utils.h"
 
 static bool runtime_workspace_desc_has_valid_layouts(
   const layout_registry_t *layouts, const workspace_desc_t *workspace) {
diff --git a/src/core/state.c b/src/core/state.c
index 987cb2b..f91ddfb 100644
--- a/src/core/state.c
+++ b/src/core/state.c
@@ -3,9 +3,10 @@
 #include <stddef.h>
 #include <string.h>
 
+#include "base/log.h"
+#include "base/memory.h"
 #include "core/types.h"
 #include "core/wm_desc.h"
-#include "utils.h"
 
 void state_init(state_t *state, const output_info_t *outputs,
                 size_t output_count, const workspace_desc_t *workspaces,
diff --git a/src/core/state.h b/src/core/state.h
index 568ee7f..0bbb66a 100644
--- a/src/core/state.h
+++ b/src/core/state.h
@@ -85,8 +85,8 @@ typedef struct state_t {
  * workspace；若某个 output 没有任何归属 workspace，state_init() 会失败。
  */
 void state_init(state_t *state, const output_info_t *outputs,
-                   size_t output_count, const workspace_desc_t *workspaces,
-                   size_t workspace_count);
+                size_t output_count, const workspace_desc_t *workspaces,
+                size_t workspace_count);
 void state_cleanup(state_t *state);
 
 /*
@@ -95,20 +95,18 @@ void state_cleanup(state_t *state);
  * 这组接口对外只提供只读访问。
  * workspace 的运行期可变状态必须通过专门的 state 级更新接口修改。
  */
-const workspace_t *state_workspace_get(const state_t *state,
-                                          workspace_id_t id);
+const workspace_t *state_workspace_get(const state_t *state, workspace_id_t id);
 const workspace_t *state_workspace_at(const state_t *state, size_t index);
-bool state_workspace_cycle_layout(state_t *state,
-                                     workspace_id_t workspace_id);
+bool state_workspace_cycle_layout(state_t *state, workspace_id_t workspace_id);
 bool state_workspace_set_layout_by_index(state_t *state,
-                                            workspace_id_t workspace_id,
-                                            size_t index);
-bool state_workspace_set_layout_by_id(state_t *state,
                                          workspace_id_t workspace_id,
-                                         layout_id_t layout_id);
+                                         size_t index);
+bool state_workspace_set_layout_by_id(state_t *state,
+                                      workspace_id_t workspace_id,
+                                      layout_id_t layout_id);
 void state_workspace_set_focused_window(state_t *state,
-                                           workspace_id_t workspace_id,
-                                           window_id_t window_id);
+                                        workspace_id_t workspace_id,
+                                        window_id_t window_id);
 size_t state_workspace_count(const state_t *state);
 bool state_workspace_valid(const state_t *state, workspace_id_t id);
 
@@ -121,10 +119,9 @@ bool state_workspace_valid(const state_t *state, workspace_id_t id);
 const output_t *state_output_get(const state_t *state, output_id_t id);
 const output_t *state_output_at(const state_t *state, size_t index);
 void state_output_set_workarea(state_t *state, output_id_t output_id,
-                                  rect_t workarea);
-void state_output_set_current_workspace(state_t *state,
-                                           output_id_t output_id,
-                                           workspace_id_t workspace_id);
+                               rect_t workarea);
+void state_output_set_current_workspace(state_t *state, output_id_t output_id,
+                                        workspace_id_t workspace_id);
 size_t state_output_count(const state_t *state);
 bool state_output_valid(const state_t *state, output_id_t id);
 
@@ -142,8 +139,7 @@ bool state_output_valid(const state_t *state, output_id_t id);
  * info 提供 backend 已探测到的窗口基础信息。
  * workspace 归属与其他策略相关字段由后续 state_window_* 接口设置。
  */
-const window_t *state_window_add(state_t *state,
-                                    const window_info_t *info);
+const window_t *state_window_add(state_t *state, const window_info_t *info);
 const window_t *state_window_get(const state_t *state, window_id_t id);
 const window_t *state_window_at(const state_t *state, size_t index);
 /* 删除窗口，并同步从 stack_order[] 中移除。 */
@@ -152,31 +148,31 @@ size_t state_window_count(const state_t *state);
 
 /* state 持有的单个 window 状态更新接口 */
 void state_window_set_workspace(state_t *state, window_id_t window_id,
-                                   workspace_id_t workspace_id);
+                                workspace_id_t workspace_id);
 void state_window_set_geometry_mode(state_t *state, window_id_t window_id,
-                                       window_geometry_mode_t geometry_mode);
+                                    window_geometry_mode_t geometry_mode);
 void state_window_set_floating(state_t *state, window_id_t window_id,
-                                  bool floating);
+                               bool floating);
 void state_window_set_sticky(state_t *state, window_id_t window_id,
-                                bool sticky);
+                             bool sticky);
 void state_window_set_urgent(state_t *state, window_id_t window_id,
-                                bool urgent);
+                             bool urgent);
 void state_window_set_fixed_size(state_t *state, window_id_t window_id,
-                                    bool fixed_size);
+                                 bool fixed_size);
 void state_window_set_skip_taskbar(state_t *state, window_id_t window_id,
-                                      bool skip_taskbar);
+                                   bool skip_taskbar);
 void state_window_set_float_rect(state_t *state, window_id_t window_id,
-                                    rect_t float_rect);
+                                 rect_t float_rect);
 void state_window_set_frame_rect(state_t *state, window_id_t window_id,
-                                    rect_t frame_rect);
+                                 rect_t frame_rect);
 bool state_window_set_title(state_t *state, window_id_t window_id,
-                               const char *title);
+                            const char *title);
 bool state_window_set_app_id(state_t *state, window_id_t window_id,
-                                const char *app_id);
+                             const char *app_id);
 bool state_window_set_class(state_t *state, window_id_t window_id,
-                               const char *class_name);
+                            const char *class_name);
 bool state_window_set_instance(state_t *state, window_id_t window_id,
-                                  const char *instance_name);
+                               const char *instance_name);
 
 /*
  * state 持有的堆叠顺序接口
diff --git a/src/core/wm_desc.h b/src/core/wm_desc.h
index 5ef22bf..e9eb2d6 100644
--- a/src/core/wm_desc.h
+++ b/src/core/wm_desc.h
@@ -51,7 +51,7 @@ static inline bool workspace_desc_layouts_valid(
 }
 
 static inline bool workspace_desc_valid(const workspace_desc_t *workspace,
-                                           size_t output_count) {
+                                        size_t output_count) {
   if (!workspace || !workspace->name) return false;
   if (workspace->output_index >= output_count) return false;
 
diff --git a/src/utils.h b/src/utils.h
index 8f56875..1b01031 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -1,131 +1,8 @@
 #pragma once
 
-#include <stdarg.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
+/* Compatibility umbrella header. Prefer including headers from src/base in new
+ * code. */
 
-#define ssizeof(foo) (ssize_t)sizeof(foo)
-#define countof(foo) (ssizeof(foo) / ssizeof(foo[0]))
-
-#define p_alloc_nr(x) (((x) + 16) * 3 / 2)
-#define p_new(type, count) ((type *)xmalloc(sizeof(type) * (count)))
-#define p_clear(p, count) ((void)memset((p), 0, sizeof(*(p)) * (count)))
-#define p_realloc(pp, count) xrealloc((void *)(pp), sizeof(**(pp)) * (count))
-#define p_copy(src, count) xmemcopy((src), sizeof(*(src)) * (count))
-
-#define p_delete(mem_p)              \
-  do {                               \
-    void **__ptr = (void **)(mem_p); \
-    free(*__ptr);                    \
-    *(void **)__ptr = nullptr;       \
-  } while (0)
-
-#ifdef __GNUC__
-#define likely(expr) __builtin_expect(!!(expr), 1)
-#define unlikely(expr) __builtin_expect((expr), 0)
-#else
-#define likely(expr) expr
-#define unlikely(expr) expr
-#endif
-
-static inline char *p_strdup(const char *text) {
-  char *r = strdup(text);
-  if (!r) abort();
-  return r;
-}
-
-static inline char *p_strdup_nullable(const char *text) {
-  if (!text) return nullptr;
-  return p_strdup(text);
-}
-
-static inline void *__attribute__((malloc)) xmalloc(ssize_t size) {
-  void *ptr;
-
-  if (size <= 0) return nullptr;
-
-  ptr = calloc(1, size);
-
-  if (!ptr) abort();
-
-  return ptr;
-}
-
-static inline void *xmemcopy(const void *src, size_t n) {
-  if (!n) return nullptr;
-
-  void *mem = xmalloc(n);
-  void *ret = memcpy(mem, src, n);
-  if (ret != mem) abort();
-  return ret;
-}
-
-static inline void xrealloc(void **ptr, ssize_t newsize) {
-  if (newsize <= 0)
-    p_delete(ptr);
-  else {
-    *ptr = realloc(*ptr, newsize);
-    if (!*ptr) abort();
-  }
-}
-
-/**
- * @brief nullptr resistant strlen.
- *
- * Unlike it's libc sibling, a_strlen returns a ssize_t, and supports its
- * argument being nullptr.
- *
- * @param s the string.
- * @return the string length (or 0 if s is nullptr).
- */
-static inline ssize_t a_strlen(const char *s) { return s ? strlen(s) : 0; }
-
-#define fatal(format, ...) \
-  _fatal(__LINE__, __FUNCTION__, __FILE__, format, ##__VA_ARGS__)
-void _fatal(int line, const char *function, const char *file,
-            const char *format, ...) __attribute__((noreturn))
-__attribute__((format(printf, 4, 5)));
-
-#define warn(format, ...) \
-  _warn(__LINE__, __FUNCTION__, __FILE__, format, ##__VA_ARGS__)
-void _warn(int line, const char *function, const char *file, const char *format,
-           ...) __attribute__((format(printf, 4, 5)));
-
-const char *current_time_str(void);
-
-#if defined(RELEASE)
-#define logger(format, ...)
-#elif defined(LOG_FILE)
-static inline void logger(const char *format, ...) {
-  va_list ap;
-  va_start(ap, format);
-  FILE *log_file = fopen(LOG_FILE, "a+t");
-  vfprintf(log_file, format, ap);
-  va_end(ap);
-  fclose(log_file);
-}
-#else
-#define logger(format, ...) printf(format, ##__VA_ARGS__)
-#endif
-
-#ifdef MIN
-#undef MIN
-#endif
-#ifndef MIN
-#define MIN(a, b) (((a) < (b)) ? (a) : (b))
-#endif
-
-#ifdef MAX
-#undef MAX
-#endif
-#ifndef MAX
-#define MAX(a, b) (((a) > (b)) ? (a) : (b))
-#endif
-
-static constexpr size_t INIT_CAPACITY = 4;
-static inline size_t next_capacity(size_t capacity) {
-  if (capacity) return capacity * 2;
-  return INIT_CAPACITY;
-}
+#include "base/log.h"
+#include "base/macros.h"
+#include "base/memory.h"
diff --git a/tests/core/CMakeLists.txt b/tests/core/CMakeLists.txt
index 4a93e6f..d7d176c 100644
--- a/tests/core/CMakeLists.txt
+++ b/tests/core/CMakeLists.txt
@@ -2,7 +2,7 @@ set(TEST_APP_NAME "zdwm-tests")
 
 add_executable(${TEST_APP_NAME}
     ${CMAKE_CURRENT_SOURCE_DIR}/main.c
-    ${SOURCE_DIR}/utils.c
+    ${SOURCE_DIR}/base/log.c
     ${SOURCE_DIR}/backend/output_utils.c
     ${SOURCE_DIR}/backend/x11/backend.c
     ${SOURCE_DIR}/core/layout.c