new file mode 100644
--- /dev/null
+++ b/src/os/unix/ngx_thread_mutex.c
@@ -0,0 +1,174 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ * Copyright (C) Nginx, Inc.
+ */
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+/*
+ * All modern pthread mutex implementations try to acquire a lock
+ * atomically in userland before going to sleep in kernel.  Some
+ * spins before the sleeping.
+ *
+ * In Solaris since version 8 all mutex types spin before sleeping.
+ * The default spin count is 1000.  It can be overridden using
+ * _THREAD_ADAPTIVE_SPIN=100 environment variable.
+ *
+ * In MacOSX all mutex types spin to acquire a lock protecting a mutex's
+ * internals.  If the mutex is busy, thread calls Mach semaphore_wait().
+ *
+ *
+ * PTHREAD_MUTEX_NORMAL lacks deadlock detection and is the fastest
+ * mutex type.
+ *
+ *   Linux:    No spinning.  The internal name PTHREAD_MUTEX_TIMED_NP
+ *             remains from the times when pthread_mutex_timedlock() was
+ *             non-standard extension.  Alias name: PTHREAD_MUTEX_FAST_NP.
+ *   FreeBSD:  No spinning.
+ *
+ *
+ * PTHREAD_MUTEX_ERRORCHECK is usually as fast as PTHREAD_MUTEX_NORMAL
+ * yet has lightweight deadlock detection.
+ *
+ *   Linux:    No spinning.  The internal name: PTHREAD_MUTEX_ERRORCHECK_NP.
+ *   FreeBSD:  No spinning.
+ *
+ *
+ * PTHREAD_MUTEX_RECURSIVE allows recursive locking.
+ *
+ *   Linux:    No spinning.  The internal name: PTHREAD_MUTEX_RECURSIVE_NP.
+ *   FreeBSD:  No spinning.
+ *
+ *
+ * PTHREAD_MUTEX_ADAPTIVE_NP spins on SMP systems before sleeping.
+ *
+ *   Linux:    No deadlock detection.  Dynamically changes a spin count
+ *             for each mutex from 10 to 100 based on spin count taken
+ *             previously.
+ *   FreeBSD:  Deadlock detection.  The default spin count is 2000.
+ *             It can be overriden using LIBPTHREAD_SPINLOOPS environment
+ *             variable or by pthread_mutex_setspinloops_np().  If a lock
+ *             is still busy, sched_yield() can be called on both UP and
+ *             SMP systems.  The default yield loop count is zero, but
+ *             it can be set by LIBPTHREAD_YIELDLOOPS environment
+ *             variable or by pthread_mutex_setyieldloops_np().
+ *   Solaris:  No PTHREAD_MUTEX_ADAPTIVE_NP.
+ *   MacOSX:   No PTHREAD_MUTEX_ADAPTIVE_NP.
+ *
+ *
+ * PTHREAD_MUTEX_ELISION_NP is a Linux extension to elide locks using
+ * Intel Restricted Transactional Memory.  It is the most suitable for
+ * rwlock pattern access because it allows simultaneous reads without lock.
+ * Supported since glibc 2.18.
+ *
+ *
+ * PTHREAD_MUTEX_DEFAULT is default mutex type.
+ *
+ *   Linux:    PTHREAD_MUTEX_NORMAL.
+ *   FreeBSD:  PTHREAD_MUTEX_ERRORCHECK.
+ *   Solaris:  PTHREAD_MUTEX_NORMAL.
+ *   MacOSX:   PTHREAD_MUTEX_NORMAL.
+ */
+
+
+ngx_int_t
+ngx_thread_mutex_create(ngx_thread_mutex_t *mtx, ngx_log_t *log)
+{
+    ngx_err_t            err;
+    pthread_mutexattr_t  attr;
+
+    err = pthread_mutexattr_init(&attr);
+    if (err != 0) {
+        ngx_log_error(NGX_LOG_EMERG, log, err,
+                      "pthread_mutexattr_init() failed");
+        return NGX_ERROR;
+    }
+
+    err = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK);
+    if (err != 0) {
+        ngx_log_error(NGX_LOG_EMERG, log, err,
+                      "pthread_mutexattr_settype"
+                      "(PTHREAD_MUTEX_ERRORCHECK) failed");
+        return NGX_ERROR;
+    }
+
+    err = pthread_mutex_init(mtx, &attr);
+    if (err != 0) {
+        ngx_log_error(NGX_LOG_EMERG, log, err,
+                      "pthread_mutex_init() failed");
+        return NGX_ERROR;
+    }
+
+    err = pthread_mutexattr_destroy(&attr);
+    if (err != 0) {
+        ngx_log_error(NGX_LOG_ALERT, log, err,
+                      "pthread_mutexattr_destroy() failed");
+    }
+
+    ngx_log_debug1(NGX_LOG_DEBUG_CORE, log, 0,
+                   "pthread_mutex_init(%p)", mtx);
+    return NGX_OK;
+}
+
+
+ngx_int_t
+ngx_thread_mutex_destroy(ngx_thread_mutex_t *mtx, ngx_log_t *log)
+{
+    ngx_err_t  err;
+
+    err = pthread_mutex_destroy(mtx);
+    if (err != 0) {
+        ngx_log_error(NGX_LOG_ALERT, log, err,
+                      "pthread_mutex_destroy() failed");
+        return NGX_ERROR;
+    }
+
+    ngx_log_debug1(NGX_LOG_DEBUG_CORE, log, 0,
+                   "pthread_mutex_destroy(%p)", mtx);
+    return NGX_OK;
+}
+
+
+ngx_int_t
+ngx_thread_mutex_lock(ngx_thread_mutex_t *mtx, ngx_log_t *log)
+{
+    ngx_err_t  err;
+
+    ngx_log_debug1(NGX_LOG_DEBUG_CORE, log, 0,
+                   "pthread_mutex_lock(%p) enter", mtx);
+
+    err = pthread_mutex_lock(mtx);
+    if (err == 0) {
+        return NGX_OK;
+    }
+
+    ngx_log_error(NGX_LOG_ALERT, log, err, "pthread_mutex_lock() failed");
+
+    return NGX_ERROR;
+}
+
+
+ngx_int_t
+ngx_thread_mutex_unlock(ngx_thread_mutex_t *mtx, ngx_log_t *log)
+{
+    ngx_err_t  err;
+
+    err = pthread_mutex_unlock(mtx);
+
+#if 0
+    ngx_time_update();
+#endif
+
+    if (err == 0) {
+        ngx_log_debug1(NGX_LOG_DEBUG_CORE, log, 0,
+                       "pthread_mutex_unlock(%p) exit", mtx);
+        return NGX_OK;
+    }
+
+    ngx_log_error(NGX_LOG_ALERT, log, err, "pthread_mutex_unlock() failed");
+
+    return NGX_ERROR;
+}