From 195e1f19b06095f39a4fb0da46dfab2ec5b10e9a Mon Sep 17 00:00:00 2001
From: Tuncer Ayaz <tuncer.ayaz@gmail.com>
Date: Thu, 13 Jan 2011 12:36:14 +0100
Subject: Implement file:sendfile

Allow Erlang code to use sendfile() where available by wrapping it as
file:sendfile/4 and file:sendfile/2.

sendfile(2) - Linux man page:
"sendfile() copies data between one file descriptor and another.
Because this copying is done within the kernel, sendfile() is more
efficient than the combination of read(2) and write(2), which would
require transferring data to and from user space."
---
 lib/kernel/test/file_SUITE.erl | 87 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 86 insertions(+), 1 deletion(-)

(limited to 'lib/kernel/test/file_SUITE.erl')

diff --git a/lib/kernel/test/file_SUITE.erl b/lib/kernel/test/file_SUITE.erl
index 77fc7e73f9..67458ae77d 100644
--- a/lib/kernel/test/file_SUITE.erl
+++ b/lib/kernel/test/file_SUITE.erl
@@ -86,6 +86,8 @@
 
 -export([standard_io/1,mini_server/1]).
 
+-export([sendfile/0, sendfile/1, sendfile_server/1]).
+
 %% Debug exports
 -export([create_file_slow/2, create_file/2, create_bin/2]).
 -export([verify_file/2, verify_bin/3]).
@@ -107,7 +109,7 @@ all() ->
      delayed_write, read_ahead, segment_read, segment_write,
      ipread, pid2name, interleaved_read_write, otp_5814,
      large_file, read_line_1, read_line_2, read_line_3,
-     read_line_4, standard_io].
+     read_line_4, standard_io, sendfile].
 
 groups() -> 
     [{dirs, [], [make_del_dir, cur_dir_0, cur_dir_1]},
@@ -3950,3 +3952,86 @@ flush(Msgs) ->
     after 0 ->
 	    lists:reverse(Msgs)
     end.
+
+
+sendfile() ->
+    [{timetrap, {seconds, 5}}].
+
+sendfile_supported({unix,linux}) -> true;
+sendfile_supported({unix,sunos}) -> true;
+sendfile_supported({unix,freebsd}) -> true;
+sendfile_supported({unix,dragonfly}) -> true;
+sendfile_supported({unix,darwin}) -> true;
+%% TODO: enable win32 once TransmitFile based implemenation written properly
+%% sendfile_supported({win32,_}) -> true;
+sendfile_supported(_) -> false.
+
+sendfile(Config) when is_list(Config) ->
+    case sendfile_supported(os:type()) of
+	true ->
+	    ?line Data = ?config(data_dir, Config),
+	    ?line Real = filename:join(Data, "realmen.html"),
+	    Host = "localhost",
+
+	    %% TODO: find another way to test for {error, posix_error()}?
+	    %% Disabled because with driver_select I cannot test for
+	    %% invalid out_fd
+	    %% ?line {error, Error} = file:sendfile(Real, -1),
+	    %% ?line test_server:format("sendfile error = ~p", [Error]),
+	    %% %% Unix ebadf, Windows eio
+	    %% ?line true = Error =:= ebadf orelse Error =:= eio,
+
+	    ?line ok = sendfile_send(Host, Real);
+	false ->
+	    {skip, "sendfile not supported on this platform"}
+    end.
+
+%% TODO: consolidate tests and reduce code
+
+sendfile_send(Host, File) ->
+    {Size, _Md5} = FileInfo = sendfile_file_info(File),
+    spawn_link(?MODULE, sendfile_server, [self()]),
+    receive
+	{server, Port} ->
+	    ?line {ok, Sock} = gen_tcp:connect(Host, Port,
+					       [binary,{packet,0}]),
+	    ?line {ok, Size} = file:sendfile(File, Sock),
+	    ?line ok = gen_tcp:close(Sock),
+	    receive
+		{ok, Bin} ->
+		    ?line FileInfo = sendfile_bin_info(Bin),
+		    ok
+	    end
+    end.
+
+sendfile_server(ClientPid) ->
+    ?line {ok, LSock} = gen_tcp:listen(0, [binary, {packet, 0},
+					   {active, false},
+					   {reuseaddr, true}]),
+    ?line {ok, Port} = inet:port(LSock),
+    ClientPid ! {server, Port},
+    ?line {ok, Sock} = gen_tcp:accept(LSock),
+    ?line {ok, Bin} = sendfile_do_recv(Sock, []),
+    ?line ok = gen_tcp:close(Sock),
+    ClientPid ! {ok, Bin}.
+
+-define(SENDFILE_TIMEOUT, 5000).
+
+sendfile_do_recv(Sock, Bs) ->
+    case gen_tcp:recv(Sock, 0, ?SENDFILE_TIMEOUT) of
+	{ok, B} ->
+	    sendfile_do_recv(Sock, [B|Bs]);
+	{error, closed} ->
+	    {ok, lists:reverse(Bs)}
+    end.
+
+sendfile_file_info(File) ->
+    {ok, #file_info{size = Size}} = file:read_file_info(File),
+    {ok, Data} = file:read_file(File),
+    Md5 = erlang:md5(Data),
+    {Size, Md5}.
+
+sendfile_bin_info(Data) ->
+    Size = lists:foldl(fun(E,Sum) -> size(E) + Sum end, 0, Data),
+    Md5 = erlang:md5(Data),
+    {Size, Md5}.
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