--- a/src/event/modules/ngx_aio_module.c
+++ b/src/event/modules/ngx_aio_module.c
@@ -3,9 +3,11 @@ int ngx_posix_aio_process_events(ngx_log
 {
     unmask signal
 
-    listen via signal;
+    listen via SIGIO;
 
-    aio_suspend()/aiowait()/aio_waitcomplete();
+    /* BUG: SIGIO can be delivered before aio_*() */
+
+    aio_suspend()/aiowait()/aio_waitcomplete() with timeout
 
     mask signal
 
@@ -20,7 +22,7 @@ int ngx_posix_aio_process_events(ngx_log
 {
     unmask signal
 
-    /* BUG: signal can be delivered before select() */
+    /* BUG: AIO signal can be delivered before select() */
 
     select(listen);
 

--- a/src/http/ngx_http_filter.c
+++ b/src/http/ngx_http_filter.c
@@ -209,7 +209,12 @@ int ngx_http_filter_copy_hunk(ngx_hunk_t
         if (n == NGX_ERROR) {
             ngx_log_error(NGX_LOG_ERR, log, ngx_errno,
                           ngx_read_file_n " failed for client");
-            return NGX_ERROR;
+            return n;
+
+#if (NGX_FILE_AIO)
+        } else if (n == NGX_AGAIN) {
+            return n;
+#endif
 
         } else {
             ngx_assert((n == size), /* void */ ; , log,
@@ -229,19 +234,3 @@ int ngx_http_filter_copy_hunk(ngx_hunk_t
 
     return NGX_OK;
 }
-
-
-
-
-
-    /* if no hunk is passed and there is no our hunk
-       or our hunk is still busy then call next filter */
-    if (hunk == NULL
-        && (ctx->hunk == NULL
-            || ((ctx->hunk != NULL)
-                && (ctx->hunk->pos.mem < ctx->hunk->last.mem))
-           )
-       )
-        ctx->next_filter(r, NULL);
-    }
-}

--- a/src/os/unix/ngx_errno.h
+++ b/src/os/unix/ngx_errno.h
@@ -12,8 +12,9 @@ typedef int               ngx_err_t;
 #define NGX_EAGAIN        EWOULDBLOCK
 #define NGX_EADDRINUSE    EADDRINUSE
 
-#define ngx_errno         errno
-#define ngx_socket_errno  errno
+#define ngx_errno                  errno
+#define ngx_socket_errno           errno
+#define ngx_set_socket_errno(err)  errno = err
 
 #define ngx_strerror_r(err, errstr, size)  \
              ngx_cpystrn(errstr, strerror(err), size) - (errstr)

new file mode 100644
--- /dev/null
+++ b/src/os/unix/ngx_file.c
@@ -0,0 +1,61 @@
+
+
+ssize_t ngx_read_file(ngx_file_t file, char *buf, size_t size)
+{
+    read();
+}
+
+#if 0
+
+ssize_t ngx_read_file(ngx_file_t *file, char *buf, size_t size, off_t offset)
+{
+    if (!file->read->ready) {
+
+        ngx_memzero(&file->iocb, sizeof(iocb));
+        file->iocb.aio_fildes = file->fd;
+        file->iocb.aio_buf = buf;
+        file->iocb.aio_nbytes = size;
+        file->iocb.aio_offset = offset;
+#if (USE_AIO_KQUEUE)
+        file->iocb.aio_sigevent.sigev_notify = SIGEV_KEVENT;
+        file->iocb.aio_sigevent.sigev_notify_kqueue = tid->kq;
+        file->iocb.aio_sigevent.sigev_value = (union sigval) file;
+#endif
+#if (USE_AIO_SIGNAL)
+        file->iocb.aio_sigevent.sigev_notify = SIGEV_SIGNAL;
+        file->iocb.aio_sigevent.sigev_signo = NGX_SIGAIO;
+#ifndef __FreeBSD__
+        file->iocb.aio_sigevent.sigev_value.sival_ptr = file;
+#endif
+#endif
+
+        if (aio_read(&file->iocb) == -1) {
+            ngx_log_error(NGX_LOG_ERR, file->log, ngx_errno,
+                          "aio_read() failed");
+            return NGX_ERROR;
+
+        n = aio_error(&file->iocb);
+        if (n == EINPROGRESS)
+            return NGX_AGAIN;
+
+        if (n == -1) {
+            ngx_log_error(NGX_LOG_ERR, file->log, ngx_errno,
+                          "aio_read() failed");
+            return NGX_ERROR;
+        }
+    }
+
+    ngx_assert(file->iocb.aio_buf == buf), return NGX_ERROR,
+               "ngx_aio_read_file: another buffer is passed");
+
+    n = aio_return(&file->iocb);
+    if (n == -1) {
+        ngx_log_error(NGX_LOG_ERR, file->log, ngx_errno,
+                      "aio_read() failed");
+        return NGX_ERROR;
+    }
+
+    return n;
+}
+
+#endif

--- a/src/os/unix/ngx_file.h
+++ b/src/os/unix/ngx_file.h
@@ -10,16 +10,19 @@ typedef struct stat              ngx_fil
 
 
 #define ngx_open_file            open
-#define ngx_open_file_n          "open"
+#define ngx_open_file_n          "open()"
+
+#define ngx_read_file            read
+#define ngx_read_file_n          "read()"
 
 #define NGX_FILE_RDONLY          O_RDONLY
 
 
 #define ngx_file_type(file, sb)  stat(file, sb)
-#define ngx_file_type_n          "stat"
+#define ngx_file_type_n          "stat()"
 
 #define ngx_stat_fd(fd, sb)      fstat(fd, sb)
-#define ngx_stat_fd_n            "fstat"
+#define ngx_stat_fd_n            "fstat()"
 
 #define ngx_is_dir(sb)           (S_ISDIR(sb.st_mode))
 #define ngx_file_size(sb)        sb.st_size