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authorTuncer Ayaz <[email protected]>2011-01-13 12:36:14 +0100
committerLukas Larsson <[email protected]>2011-11-29 14:30:35 +0100
commit195e1f19b06095f39a4fb0da46dfab2ec5b10e9a (patch)
tree8f4a8c587b72c3a20d18b4cb6ccd7d1d52eb6286 /lib/kernel/src
parent7292c3d9f5285592aa4de996f6f106cd365d7895 (diff)
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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."
Diffstat (limited to 'lib/kernel/src')
-rw-r--r--lib/kernel/src/file.erl58
-rw-r--r--lib/kernel/src/file_io_server.erl8
2 files changed, 65 insertions, 1 deletions
diff --git a/lib/kernel/src/file.erl b/lib/kernel/src/file.erl
index 706c60caaf..fba9a86e95 100644
--- a/lib/kernel/src/file.erl
+++ b/lib/kernel/src/file.erl
@@ -41,7 +41,7 @@
pread/2, pread/3, pwrite/2, pwrite/3,
read_line/1,
position/2, truncate/1, datasync/1, sync/1,
- copy/2, copy/3]).
+ copy/2, copy/3, sendfile/4, sendfile/2]).
%% High level operations
-export([consult/1, path_consult/2]).
-export([eval/1, eval/2, path_eval/2, path_eval/3, path_open/3]).
@@ -335,6 +335,62 @@ raw_write_file_info(Name, #file_info{} = Info) ->
Error
end.
+%% sendfile/5
+%% TODO: add more guards? export sendfile/5?
+-spec sendfile(File, Sock, Offset, Bytes, ChunkSize)
+ -> {'ok', non_neg_integer()} | {'error', posix()} when
+ File::io_device(), Sock::port() | integer(),
+ Offset::non_neg_integer(), Bytes::non_neg_integer(),
+ ChunkSize::non_neg_integer().
+sendfile(File, Sock, Offset, Bytes, ChunkSize) when is_integer(Sock)
+ andalso is_pid(File) ->
+ R = file_request(File, {sendfile, Sock, Offset, Bytes, ChunkSize}),
+ wait_file_reply(File, R);
+sendfile(File, Sock, Offset, Bytes, ChunkSize) when is_port(Sock)
+ andalso is_pid(File) ->
+ {ok, SockFD} = prim_inet:getfd(Sock),
+ sendfile(File, SockFD, Offset, Bytes, ChunkSize);
+sendfile(#file_descriptor{module = Module} = Handle, Sock,
+ Offset, Bytes, ChunkSize) when is_integer(Sock) ->
+ Module:sendfile(Handle, Sock, Offset, Bytes, ChunkSize);
+sendfile(#file_descriptor{module = _Module} = Handle, Sock,
+ Offset, Bytes, ChunkSize) when is_port(Sock) ->
+ {ok, SockFD} = prim_inet:getfd(Sock),
+ sendfile(Handle, SockFD, Offset, Bytes, ChunkSize);
+sendfile(_, _, _, _, _) ->
+ {error, badarg}.
+
+-define(SENDFILE_CHUNK_LIMIT, 2147483648). % 2GB
+
+%% Limit chunksize to work around 4 byte off_t/size_t limits
+sendfile_chunksize(Bytes, Limit) ->
+ case Bytes >= Limit of
+ true -> Limit - 1;
+ false -> Bytes
+ end.
+
+-spec sendfile(File, Sock, Offset, Bytes)
+ -> {'ok', non_neg_integer()} | {'error', posix()} when
+ File::io_device(), Sock::port() | integer(),
+ Offset::non_neg_integer(), Bytes::non_neg_integer().
+sendfile(File, Sock, Offset, Bytes) ->
+ ChunkSize = sendfile_chunksize(Bytes, ?SENDFILE_CHUNK_LIMIT),
+ sendfile(File, Sock, Offset, Bytes, ChunkSize).
+
+%% sendfile/2
+%% TODO: add guards?
+-spec sendfile(File, Sock) -> {'ok', non_neg_integer()} | {'error', posix()}
+ when File::name(), Sock::port().
+sendfile(File, Sock) ->
+ Offset = 0,
+ {ok, #file_info{size = Bytes}} = read_file_info(File),
+ %% TODO: use file:open/2 and file:read_file_info/1 instead of local calls?
+ {ok, Fd} = open(File, [read, raw, binary]),
+ ChunkSize = sendfile_chunksize(Bytes, ?SENDFILE_CHUNK_LIMIT),
+ Res = sendfile(Fd, Sock, Offset, Bytes, ChunkSize),
+ ok = close(Fd),
+ Res.
+
%%%-----------------------------------------------------------------
%%% File io server functions.
%%% They operate on a single open file.
diff --git a/lib/kernel/src/file_io_server.erl b/lib/kernel/src/file_io_server.erl
index 14da9c1a55..78d3d24394 100644
--- a/lib/kernel/src/file_io_server.erl
+++ b/lib/kernel/src/file_io_server.erl
@@ -249,6 +249,14 @@ file_request(close,
file_request({position,At},
#state{handle=Handle,buf=Buf}=State) ->
std_reply(position(Handle, At, Buf), State);
+file_request({sendfile,DestFD,Offset,Bytes,ChunkSize},
+ #state{handle=Handle}=State) ->
+ case ?PRIM_FILE:sendfile(Handle, DestFD, Offset, Bytes, ChunkSize) of
+ {error,_}=Reply ->
+ {stop,normal,Reply,State};
+ Reply ->
+ {reply,Reply,State}
+ end;
file_request(truncate,
#state{handle=Handle}=State) ->
case ?PRIM_FILE:truncate(Handle) of