new file mode 100644
--- /dev/null
+++ b/src/core/ngx_log.h
@@ -0,0 +1,210 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#ifndef _NGX_LOG_H_INCLUDED_
+#define _NGX_LOG_H_INCLUDED_
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+#define NGX_LOG_STDERR            0
+#define NGX_LOG_EMERG             1
+#define NGX_LOG_ALERT             2
+#define NGX_LOG_CRIT              3
+#define NGX_LOG_ERR               4
+#define NGX_LOG_WARN              5
+#define NGX_LOG_NOTICE            6
+#define NGX_LOG_INFO              7
+#define NGX_LOG_DEBUG             8
+
+#define NGX_LOG_DEBUG_CORE        0x010
+#define NGX_LOG_DEBUG_ALLOC       0x020
+#define NGX_LOG_DEBUG_MUTEX       0x040
+#define NGX_LOG_DEBUG_EVENT       0x080
+#define NGX_LOG_DEBUG_HTTP        0x100
+#define NGX_LOG_DEBUG_IMAP        0x200
+
+/*
+ * do not forget to update debug_levels[] in src/core/ngx_log.c
+ * after the adding a new debug level
+ */
+
+#define NGX_LOG_DEBUG_FIRST       NGX_LOG_DEBUG_CORE
+#define NGX_LOG_DEBUG_LAST        NGX_LOG_DEBUG_IMAP
+#define NGX_LOG_DEBUG_CONNECTION  0x80000000
+#define NGX_LOG_DEBUG_ALL         0x7ffffff0
+
+
+typedef size_t  (*ngx_log_handler_pt) (void *ctx, char *buf, size_t len);
+
+
+struct ngx_log_s {
+    ngx_uint_t           log_level;
+    ngx_open_file_t     *file;
+    void                *data;
+    ngx_log_handler_pt   handler;
+};
+
+#define MAX_ERROR_STR	 2048
+
+
+/*********************************/
+
+#if (HAVE_GCC_VARIADIC_MACROS)
+
+#define HAVE_VARIADIC_MACROS  1
+
+#define ngx_log_error(level, log, args...) \
+        if (log->log_level >= level) ngx_log_error_core(level, log, args)
+
+void ngx_log_error_core(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
+                        const char *fmt, ...);
+
+/*********************************/
+
+#elif (HAVE_C99_VARIADIC_MACROS)
+
+#define HAVE_VARIADIC_MACROS  1
+
+#define ngx_log_error(level, log, ...) \
+        if (log->log_level >= level) ngx_log_error_core(level, log, __VA_ARGS__)
+
+void ngx_log_error_core(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
+                        const char *fmt, ...);
+
+/*********************************/
+
+#else /* NO VARIADIC MACROS */
+
+#define HAVE_VARIADIC_MACROS  0
+
+void ngx_log_error(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
+                   const char *fmt, ...);
+void ngx_log_error_core(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
+                        const char *fmt, va_list args);
+void ngx_log_debug_core(ngx_log_t *log, ngx_err_t err, const char *fmt, ...);
+void ngx_assert_core(ngx_log_t *log, const char *fmt, ...);
+
+
+#endif /* VARIADIC MACROS */
+
+
+/*********************************/
+
+#if (NGX_DEBUG)
+
+#if (HAVE_VARIADIC_MACROS)
+
+#define ngx_log_debug0(level, log, err, fmt) \
+    if (log->log_level & level) \
+        ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt)
+
+#define ngx_log_debug1(level, log, err, fmt, arg1) \
+    if (log->log_level & level) \
+        ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt, arg1)
+
+#define ngx_log_debug2(level, log, err, fmt, arg1, arg2) \
+    if (log->log_level & level) \
+        ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt, arg1, arg2)
+
+#define ngx_log_debug3(level, log, err, fmt, arg1, arg2, arg3) \
+    if (log->log_level & level) \
+        ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt, arg1, arg2, arg3)
+
+#define ngx_log_debug4(level, log, err, fmt, arg1, arg2, arg3, arg4) \
+    if (log->log_level & level) \
+        ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt, arg1, arg2, arg3, arg4)
+
+#define ngx_log_debug5(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5) \
+    if (log->log_level & level) \
+        ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt, \
+                           arg1, arg2, arg3, arg4, arg5)
+
+#define ngx_log_debug6(level, log, err, fmt, \
+                       arg1, arg2, arg3, arg4, arg5, arg6) \
+    if (log->log_level & level) \
+        ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt, \
+                           arg1, arg2, arg3, arg4, arg5, arg6)
+
+#define ngx_log_debug7(level, log, err, fmt, \
+                       arg1, arg2, arg3, arg4, arg5, arg6, arg7) \
+    if (log->log_level & level) \
+        ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt, \
+                           arg1, arg2, arg3, arg4, arg5, arg6, arg7)
+
+#else /* NO VARIADIC MACROS */
+
+#define ngx_log_debug0(level, log, err, fmt) \
+    if (log->log_level & level) \
+        ngx_log_debug_core(log, err, fmt)
+
+#define ngx_log_debug1(level, log, err, fmt, arg1) \
+    if (log->log_level & level) \
+        ngx_log_debug_core(log, err, fmt, arg1)
+
+#define ngx_log_debug2(level, log, err, fmt, arg1, arg2) \
+    if (log->log_level & level) \
+        ngx_log_debug_core(log, err, fmt, arg1, arg2)
+
+#define ngx_log_debug3(level, log, err, fmt, arg1, arg2, arg3) \
+    if (log->log_level & level) \
+        ngx_log_debug_core(log, err, fmt, arg1, arg2, arg3)
+
+#define ngx_log_debug4(level, log, err, fmt, arg1, arg2, arg3, arg4) \
+    if (log->log_level & level) \
+        ngx_log_debug_core(log, err, fmt, arg1, arg2, arg3, arg4)
+
+#define ngx_log_debug5(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5) \
+    if (log->log_level & level) \
+        ngx_log_debug_core(log, err, fmt, arg1, arg2, arg3, arg4, arg5)
+
+#define ngx_log_debug6(level, log, err, fmt, \
+                       arg1, arg2, arg3, arg4, arg5, arg6) \
+    if (log->log_level & level) \
+        ngx_log_debug_core(log, err, fmt, arg1, arg2, arg3, arg4, arg5, arg6)
+
+#define ngx_log_debug7(level, log, err, fmt, \
+                       arg1, arg2, arg3, arg4, arg5, arg6, arg7) \
+    if (log->log_level & level) \
+        ngx_log_debug_core(log, err, fmt, \
+                       arg1, arg2, arg3, arg4, arg5, arg6, arg7)
+
+#endif
+
+#else /* NO NGX_DEBUG */
+
+#define ngx_log_debug0(level, log, err, fmt)
+#define ngx_log_debug1(level, log, err, fmt, arg1)
+#define ngx_log_debug2(level, log, err, fmt, arg1, arg2)
+#define ngx_log_debug3(level, log, err, fmt, arg1, arg2, arg3)
+#define ngx_log_debug4(level, log, err, fmt, arg1, arg2, arg3, arg4)
+#define ngx_log_debug5(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5)
+#define ngx_log_debug6(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5, arg6)
+#define ngx_log_debug7(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5,    \
+                       arg6, arg7)
+
+#endif
+
+/*********************************/
+
+#define ngx_log_alloc_log(pool, log)  ngx_palloc(pool, log, sizeof(ngx_log_t))
+#define ngx_log_copy_log(new, old)    ngx_memcpy(new, old, sizeof(ngx_log_t))
+
+ngx_log_t *ngx_log_init_stderr();
+#if 0
+ngx_int_t ngx_log_init_error_log();
+#endif
+ngx_log_t *ngx_log_create_errlog(ngx_cycle_t *cycle, ngx_array_t *args);
+char *ngx_set_error_log_levels(ngx_conf_t *cf, ngx_log_t *log);
+
+
+
+extern ngx_module_t  ngx_errlog_module;
+
+
+#endif /* _NGX_LOG_H_INCLUDED_ */