aboutsummaryrefslogtreecommitdiffstats
path: root/lib
diff options
context:
space:
mode:
Diffstat (limited to 'lib')
-rw-r--r--lib/ssh/doc/src/ssh_sftp.xml106
-rw-r--r--lib/stdlib/src/erl_tar.erl43
2 files changed, 126 insertions, 23 deletions
diff --git a/lib/ssh/doc/src/ssh_sftp.xml b/lib/ssh/doc/src/ssh_sftp.xml
index 251f5a4be3..ab111562f9 100644
--- a/lib/ssh/doc/src/ssh_sftp.xml
+++ b/lib/ssh/doc/src/ssh_sftp.xml
@@ -196,19 +196,113 @@
</func>
<func>
- <name>open_tar(ChannelPid, Path) -></name>
- <name>open_tar(ChannelPid, Path, Timeout) -> {ok, Handle} | {error, Reason}</name>
- <fsummary>Open a tar file on the server to which <v>ChannelPid</v> is connected and return a handle</fsummary>
+ <name>open_tar(ChannelPid, Path, Mode) -></name>
+ <name>open_tar(ChannelPid, Path, Mode, Timeout) -> {ok, Handle} | {error, Reason}</name>
+ <fsummary>Opens a tar file on the server to which <v>ChannelPid</v> is connected and returns a handle</fsummary>
<type>
<v>ChannelPid = pid()</v>
<v>Path = string()</v>
+ <v>Mode = [read] | [write] | [read,EncryptOpt] | [write,DecryptOpt] </v>
+ <v>EncryptOpt = {crypto,{InitFun,EncryptFun,CloseFun}}</v>
+ <v>DecryptOpt = {crypto,{InitFun,DecryptFun}}</v>
+ <v>InitFun = (fun() -> {ok,CryptoState}) | (fun() -> {ok,CryptoState,ChunkSize}) </v>
+ <v>CryptoState = any()</v>
+ <v>ChunkSize = undefined | pos_integer()</v>
+ <v>EncryptFun = (fun(PlainBin,CryptoState) -> EncryptResult)</v>
+ <v>EncryptResult = {ok,EncryptedBin,CryptoState} | {ok,EncryptedBin,CryptoState,ChunkSize}</v>
+ <v>PlainBin = binary()</v>
+ <v>EncryptedBin = binary()</v>
+ <v>DecryptFun = (fun(EncryptedBin,CryptoState) -> DecryptResult)</v>
+ <v>DecryptResult = {ok,PlainBin,CryptoState} | {ok,PlainBin,CryptoState,ChunkSize}</v>
+ <v>CloseFun = (fun(PlainBin,CryptoState) -> {ok,EncryptedBin})</v>
<v>Timeout = timeout()</v>
<v>Reason = term()</v>
</type>
<desc>
- <p>Opens a handle to a tar file on the server, the handle
- can be used for remote tar manipulation as defined by the
- <seealso marker="stdlib:erl_tar#init/3">erl_tar:init/3</seealso> function.</p>
+ <p>Opens a handle to a tar file on the server associated with <c>ChannelPid</c>. The handle
+ can be used for remote tar creation and extraction as defined by the
+ <seealso marker="stdlib:erl_tar#init/3">erl_tar:init/3</seealso> function.
+ </p>
+ <p>An example of writing and then reading a tar file:</p>
+ <code type="none">
+ {ok,HandleWrite} = ssh_sftp:open_tar(ChannelPid, ?tar_file_name, [write]),
+ ok = erl_tar:add(HandleWrite, .... ),
+ ok = erl_tar:add(HandleWrite, .... ),
+ ...
+ ok = erl_tar:add(HandleWrite, .... ),
+ ok = erl_tar:close(HandleWrite),
+
+ %% And for reading
+ {ok,HandleRead} = ssh_sftp:open_tar(ChannelPid, ?tar_file_name, [read]),
+ {ok,NameValueList} = erl_tar:extract(HandleRead,[memory]),
+ ok = erl_tar:close(HandleRead),
+ </code>
+
+ <p>The <c>crypto</c> mode option is applied to the generated stream of bytes just prior to sending
+ them to the sftp server. This is intended for encryption but could of course be used for other
+ purposes.
+ </p>
+ <p>The <c>InitFun</c> is applied once
+ prior to any other crypto operation. The returned <c>CryptoState</c> is then folded into
+ repeated applications of the <c>EncryptFun</c> or <c>DecryptFun</c>. The binary returned
+ from those Funs are sent further to the remote sftp server. Finally - if doing encryption
+ - the <c>CloseFun</c> is applied to the last piece of data. The <c>CloseFun</c> is
+ responsible for padding (if needed) and encryption of that last piece.
+ </p>
+ <p>The <c>ChunkSize</c> defines the size of the <c>PlainBin</c>s that <c>EncodeFun</c> is applied
+ to. If the <c>ChunkSize</c> is <c>undefined</c> the size of the <c>PlainBin</c>s varies because
+ this is inteded for stream crypto while a fixed <c>ChunkSize</c> is intended for block crypto. It
+ is possible to change the <c>ChunkSize</c>s in the return from the <c>EncryptFun</c> or
+ <c>DecryptFun</c>. It is in fact possible to change the value between <c>pos_integer()</c> and
+ <c>undefined</c>.
+ </p>
+ <p>The write and read example above can be extended with encryption and decryption:</p>
+ <code type="none">
+ %% First three parameters depending on which crypto type we select:
+ Key = &lt;&lt;"This is a 256 bit key. abcdefghi">>,
+ Ivec0 = crypto:rand_bytes(16),
+ DataSize = 1024, % DataSize rem 16 = 0 for aes_cbc
+
+ %% Initialization of the CryptoState, in this case it is the Ivector.
+ InitFun = fun() -> {ok, Ivec0, DataSize} end,
+
+ %% How to encrypt:
+ EncryptFun =
+ fun(PlainBin,Ivec) ->
+ EncryptedBin = crypto:block_encrypt(aes_cbc256, Key, Ivec, PlainBin),
+ {ok, EncryptedBin, crypto:next_iv(aes_cbc,EncryptedBin)}
+ end,
+
+ %% What to do with the very last block:
+ CloseFun =
+ fun(PlainBin, Ivec) ->
+ EncryptedBin = crypto:block_encrypt(aes_cbc256, Key, Ivec,
+ pad(16,PlainBin) %% Last chunk
+ ),
+ {ok, EncryptedBin}
+ end,
+
+ Cw = {InitFun,EncryptFun,CloseFun},
+ {ok,HandleWrite} = ssh_sftp:open_tar(ChannelPid, ?tar_file_name, [write,{crypto,Cw}]),
+ ok = erl_tar:add(HandleWrite, .... ),
+ ok = erl_tar:add(HandleWrite, .... ),
+ ...
+ ok = erl_tar:add(HandleWrite, .... ),
+ ok = erl_tar:close(HandleWrite),
+
+ %% And for decryption (in this crypto example we could use the same InitFun
+ %% as for encryption):
+ DecryptFun =
+ fun(EncryptedBin,Ivec) ->
+ PlainBin = crypto:block_decrypt(aes_cbc256, Key, Ivec, EncryptedBin),
+ {ok, PlainBin, crypto:next_iv(aes_cbc,EncryptedBin)}
+ end,
+
+ Cr = {InitFun,DecryptFun},
+ {ok,HandleRead} = ssh_sftp:open_tar(ChannelPid, ?tar_file_name, [read,{crypto,Cw}]),
+ {ok,NameValueList} = erl_tar:extract(HandleRead,[memory]),
+ ok = erl_tar:close(HandleRead),
+ </code>
</desc>
</func>
diff --git a/lib/stdlib/src/erl_tar.erl b/lib/stdlib/src/erl_tar.erl
index ab6223c0fe..caa3276d09 100644
--- a/lib/stdlib/src/erl_tar.erl
+++ b/lib/stdlib/src/erl_tar.erl
@@ -36,7 +36,7 @@
%% Opens a tar archive.
init(UsrHandle, AccessMode, Fun) when is_function(Fun,2) ->
- {ok, {AccessMode,{UsrHandle,Fun}}}.
+ {ok, {AccessMode,{tar_descriptor,UsrHandle,Fun}}}.
%%%================================================================
%%% The open function with friends is to keep the file and binary api of this module
@@ -532,27 +532,36 @@ read_opts([_|Rest], Opts) ->
read_opts([], Opts) ->
Opts.
+foldl_read({AccessMode,TD={tar_descriptor,_UsrHandle,_AccessFun}}, Fun, Accu, Opts) ->
+ case AccessMode of
+ read ->
+ foldl_read0(TD, Fun, Accu, Opts);
+ _ ->
+ {error,{read_mode_expected,AccessMode}}
+ end;
foldl_read(TarName, Fun, Accu, Opts) ->
case open(TarName, [read|Opts#read_opts.open_mode]) of
{ok, {read, File}} ->
- Result =
- case catch foldl_read1(Fun, Accu, File, Opts) of
- {'EXIT', Reason} ->
- exit(Reason);
- {error, {Reason, Format, Args}} ->
- read_verbose(Opts, Format, Args),
- {error, Reason};
- {error, Reason} ->
- {error, Reason};
- Ok ->
- Ok
- end,
+ Result = foldl_read0(File, Fun, Accu, Opts),
ok = do_close(File),
Result;
Error ->
Error
end.
+foldl_read0(File, Fun, Accu, Opts) ->
+ case catch foldl_read1(Fun, Accu, File, Opts) of
+ {'EXIT', Reason} ->
+ exit(Reason);
+ {error, {Reason, Format, Args}} ->
+ read_verbose(Opts, Format, Args),
+ {error, Reason};
+ {error, Reason} ->
+ {error, Reason};
+ Ok ->
+ Ok
+ end.
+
foldl_read1(Fun, Accu0, File, Opts) ->
case get_header(File) of
eof ->
@@ -1014,10 +1023,10 @@ open_mode(_, _, _, _) ->
{error, einval}.
%%%================================================================
-do_write({UsrHandle,Fun}, Data) -> Fun(write,{UsrHandle,Data}).
+do_write({tar_descriptor,UsrHandle,Fun}, Data) -> Fun(write,{UsrHandle,Data}).
-do_position({UsrHandle,Fun}, Pos) -> Fun(position,{UsrHandle,Pos}).
+do_position({tar_descriptor,UsrHandle,Fun}, Pos) -> Fun(position,{UsrHandle,Pos}).
-do_read({UsrHandle,Fun}, Len) -> Fun(read2,{UsrHandle,Len}).
+do_read({tar_descriptor,UsrHandle,Fun}, Len) -> Fun(read2,{UsrHandle,Len}).
-do_close({UsrHandle,Fun}) -> Fun(close,UsrHandle).
+do_close({tar_descriptor,UsrHandle,Fun}) -> Fun(close,UsrHandle).
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-03 13:41:00 +0000