new file mode 100644
--- /dev/null
+++ b/src/os/unix/ngx_readv_chain.c
@@ -0,0 +1,219 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_event.h>
+
+
+#if (HAVE_KQUEUE)
+
+ssize_t ngx_readv_chain(ngx_connection_t *c, ngx_chain_t *chain)
+{
+    u_char        *prev;
+    ssize_t        n, size;
+    ngx_err_t      err;
+    ngx_array_t    io;
+    ngx_event_t   *rev;
+    struct iovec  *iov;
+
+    rev = c->read; 
+
+    if (ngx_event_flags & NGX_HAVE_KQUEUE_EVENT) {
+        ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0,
+                       "readv: eof:%d, avail:%d, err:%d",
+                       rev->pending_eof, rev->available, rev->kq_errno);
+
+        if (rev->available == 0) {
+            if (rev->pending_eof) {
+                rev->ready = 0;
+                rev->eof = 1;
+
+                ngx_log_error(NGX_LOG_INFO, c->log, rev->kq_errno,
+                              "kevent() reported about an closed connection");
+
+                if (rev->kq_errno) {
+                    rev->error = 1;
+                    ngx_set_socket_errno(rev->kq_errno);
+                    return NGX_ERROR;
+                }
+
+                return 0;
+
+            } else {
+                return NGX_AGAIN;
+            }
+        }
+    }
+
+    prev = NULL;
+    iov = NULL;
+    size = 0;
+
+    ngx_init_array(io, c->pool, 10, sizeof(struct iovec), NGX_ERROR);
+
+    /* coalesce the neighbouring bufs */
+
+    while (chain) {
+        if (prev == chain->buf->last) {
+            iov->iov_len += chain->buf->end - chain->buf->last;
+
+        } else {
+            ngx_test_null(iov, ngx_push_array(&io), NGX_ERROR);
+            iov->iov_base = (void *) chain->buf->last;
+            iov->iov_len = chain->buf->end - chain->buf->last;
+        }
+
+        size += chain->buf->end - chain->buf->last;
+        prev = chain->buf->end;
+        chain = chain->next;
+    }
+
+    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
+                   "readv: %d, last:%d", io.nelts, iov->iov_len);
+
+    rev = c->read;
+
+    do {
+        n = readv(c->fd, (struct iovec *) io.elts, io.nelts);
+
+        if (n >= 0) {
+            if (ngx_event_flags & NGX_HAVE_KQUEUE_EVENT) {
+                rev->available -= n;
+
+                /*
+                 * rev->available can be negative here because some additional
+                 * bytes can be received between kevent() and recv()
+                 */
+
+                if (rev->available <= 0) {
+                    if (!rev->pending_eof) {
+                        rev->ready = 0;
+                    }
+
+                    if (rev->available < 0) {
+                        rev->available = 0;
+                    }
+                }
+
+                return n;
+            }
+
+            if (n < size) {
+                rev->ready = 0;
+            }
+
+            if (n == 0) {
+                rev->eof = 1;
+            }
+
+            return n;
+        }
+
+        err = ngx_socket_errno;
+
+        if (err == NGX_EAGAIN || err == NGX_EINTR) {
+            ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err,
+                           "readv() not ready");
+            n = NGX_AGAIN;
+
+        } else {
+            n = ngx_connection_error(c, err, "readv() failed");
+            break;
+        }
+
+    } while (err == NGX_EINTR);
+
+    rev->ready = 0;
+
+    if (n == NGX_ERROR){
+        c->read->error = 1;
+    }
+
+    return n;
+}
+
+#else /* ! NAVE_KQUEUE */
+
+ssize_t ngx_readv_chain(ngx_connection_t *c, ngx_chain_t *chain)
+{
+    u_char        *prev;
+    ssize_t        n, size;
+    ngx_err_t      err;
+    ngx_array_t    io;
+    ngx_event_t   *rev;
+    struct iovec  *iov;
+
+    prev = NULL;
+    iov = NULL;
+    size = 0;
+
+    ngx_init_array(io, c->pool, 10, sizeof(struct iovec), NGX_ERROR);
+
+    /* coalesce the neighbouring bufs */
+
+    while (chain) {
+        if (prev == chain->buf->last) {
+            iov->iov_len += chain->buf->end - chain->buf->last;
+
+        } else {
+            ngx_test_null(iov, ngx_push_array(&io), NGX_ERROR);
+            iov->iov_base = chain->buf->last;
+            iov->iov_len = chain->buf->end - chain->buf->last;
+        }
+
+        size += chain->buf->end - chain->buf->last;
+        prev = chain->buf->end;
+        chain = chain->next;
+    }
+
+    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
+                   "readv: %d:%d", io.nelts, iov->iov_len);
+
+    rev = c->read;
+
+    do {
+        n = readv(c->fd, (struct iovec *) io.elts, io.nelts);
+
+        if (n == 0) {
+            rev->ready = 0;
+            rev->eof = 1;
+
+            return n;
+
+        } else if (n > 0) {
+
+            if (n < size && !(ngx_event_flags & NGX_HAVE_GREEDY_EVENT)) {
+                rev->ready = 0;
+            }
+
+            return n;
+        }
+
+        err = ngx_socket_errno;
+
+        if (err == NGX_EAGAIN || err == NGX_EINTR) {
+            ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err,
+                           "readv() not ready");
+            n = NGX_AGAIN;
+
+        } else {
+            n = ngx_connection_error(c, err, "readv() failed");
+            break;
+        }
+
+    } while (err == NGX_EINTR);
+
+    rev->ready = 0;
+
+    if (n == NGX_ERROR){
+        c->read->error = 1;
+    }
+
+    return n;
+}
+
+#endif /* NAVE_KQUEUE */