new file mode 100644
--- /dev/null
+++ b/src/os/unix/ngx_user.c
@@ -0,0 +1,85 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+/*
+ * Solaris has thread-safe crypt()
+ * Linux has crypt_r(); "struct crypt_data" is more than 128K
+ * FreeBSD needs the mutex to protect crypt()
+ *
+ * TODO:
+ *     ngx_crypt_init() to init mutex
+ */
+
+
+#if (NGX_LINUX)
+
+ngx_int_t
+ngx_crypt(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
+{
+    char               *value;
+    size_t              len;
+    struct crypt_data   cd;
+
+    value = crypt_r((char *) key, (char *) salt, &cd);
+
+    if (value) {
+        len = ngx_strlen(value);
+
+        *encrypted = ngx_palloc(pool, len);
+        if (*encrypted) {
+            ngx_memcpy(*encrypted, value, len + 1);
+            return NGX_OK;
+        }
+    }
+
+    return NGX_ERROR;
+}
+
+#else
+
+ngx_int_t
+ngx_crypt(ngx_pool_t *pool, u_char *key, u_char *salt, u_char **encrypted)
+{
+    char       *value;
+    size_t      len;
+    ngx_int_t   rc;
+
+#if (NGX_THREADS && NGX_NONREENTRANT_CRYPT)
+
+    /* crypt() is a time consuming funtion, so we only try to lock */
+
+    if (ngx_mutex_trylock(ngx_crypt_mutex) != NGX_OK) {
+        return NGX_AGAIN;
+    }
+
+#endif
+
+    rc = NGX_ERROR;
+
+    value = crypt((char *) key, (char *) salt);
+
+    if (value) {
+        len = ngx_strlen(value);
+
+        *encrypted = ngx_palloc(pool, len);
+        if (*encrypted) {
+            ngx_memcpy(*encrypted, value, len + 1);
+            rc = NGX_OK;
+        }
+    }
+
+#if (NGX_THREADS && NGX_NONREENTRANT_CRYPT)
+    ngx_mutex_unlock(ngx_crypt_mutex);
+#endif
+
+    return rc;
+}
+
+#endif