File 0298-ssh-Document-the-exec-option.patch of Package erlang
From 3eced27f96d87eac1fc90325d7030167805309a1 Mon Sep 17 00:00:00 2001
From: Hans Nilsson <hans@erlang.org>
Date: Thu, 8 Mar 2018 16:34:21 +0100
Subject: [PATCH 2/2] ssh: Document the exec option
---
lib/ssh/doc/src/ssh.xml | 93 +++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 86 insertions(+), 7 deletions(-)
diff --git a/lib/ssh/doc/src/ssh.xml b/lib/ssh/doc/src/ssh.xml
index acf94ff6af..d36be8431c 100644
--- a/lib/ssh/doc/src/ssh.xml
+++ b/lib/ssh/doc/src/ssh.xml
@@ -67,24 +67,41 @@
<taglist>
<tag><c>boolean() =</c></tag>
<item><p><c>true | false</c></p></item>
+
<tag><c>string() =</c></tag>
<item><p><c>[byte()]</c></p></item>
+
<tag><c>ssh_daemon_ref() =</c></tag>
<item><p>opaque() -
as returned by <c>ssh:daemon/[1,2,3]</c></p></item>
+
+ <tag><c>ok_error(OKtype) = </c></tag>
+ <item><p><c>{ok,OKtype} | {error, term()}</c></p></item>
+
+ <tag><c>ok_error() = </c></tag>
+ <item><p><c>ok_error(term())</c></p></item>
+
<tag><c>ssh_connection_ref() =</c></tag>
<item><p>opaque() - as returned by <c>ssh:connect/3</c></p></item>
+
<tag><c>ip_address() =</c></tag>
- <item><p><c>inet::ip_address</c></p></item>
+ <item><p><c>inet::ip_address()</c></p></item>
+
+ <tag><c>port_number() =</c></tag>
+ <item><p><c>inet::port_number()</c></p></item>
+
<tag><c>subsystem_spec() =</c></tag>
<item><p><c>{subsystem_name(),
{channel_callback(), channel_init_args()}}</c></p></item>
+
<tag><c>subsystem_name() =</c></tag>
<item><p><c>string()</c></p></item>
+
<tag><c>channel_callback() =</c></tag>
<item><p><c>atom()</c> - Name of the Erlang module
implementing the subsystem using the <c>ssh_channel</c> behavior, see
<seealso marker="ssh_channel">ssh_channel(3)</seealso></p></item>
+
<tag><c>key_cb() =</c></tag>
<item>
<p><c>atom() | {atom(), list()}</c></p>
@@ -94,6 +111,7 @@
case maybe.</p>
<p><c>list()</c> - List of options that can be passed to the callback module.</p>
</item>
+
<tag><c>channel_init_args() =</c></tag>
<item><p><c>list()</c></p></item>
@@ -478,8 +496,8 @@
<v>Option = client_version | server_version | user | peer | sockname </v>
<v>Value = [option_value()] </v>
<v>option_value() = {{Major::integer(), Minor::integer()}, VersionString::string()} |
- User::string() | Peer::{inet:hostname(), {inet::ip_adress(), inet::port_number()}} |
- Sockname::{inet::ip_adress(), inet::port_number()}</v>
+ User::string() | Peer::{inet:hostname(), {ip_address(), port_number()}} |
+ Sockname::{ip_address(), port_number()}</v>
</type>
<desc>
<p>Retrieves information about a connection.</p>
@@ -541,22 +559,83 @@
The option can be set to the empty list if
you do not want the daemon to run any subsystems.</p>
</item>
- <tag><c><![CDATA[{shell, {Module, Function, Args} |
+
+ <tag><marker id="daemon_opt_shell"/>
+ <c><![CDATA[{shell, {Module, Function, Args} |
fun(string() = User) - > pid() | fun(string() = User,
ip_address() = PeerAddr) -> pid()}]]></c></tag>
<item>
<p>Defines the read-eval-print loop used when a shell is
requested by the client. The default is to use the Erlang shell:
<c><![CDATA[{shell, start, []}]]></c></p>
+ <p>See the option <seealso marker="#daemon_opt_exec"><c>exec</c></seealso>
+ for a description of how the daemon execute exec-requests depending on
+ the shell- and exec-options.</p>
+ </item>
+
+ <tag><marker id="daemon_opt_exec"/>
+ <c><![CDATA[{exec, {direct, exec_spec()}}]]></c>
+ <br/><c>where:</c>
+ <br/><c>exec_spec() = </c>
+ <br/><c> fun(Cmd::string()) -> ok_error()</c>
+ <br/><c> | fun(Cmd::string(), User::string()) -> ok_error()</c>
+ <br/><c> | fun(Cmd::string(), User::string(), ClientAddr::{ip_address(), port_number()}) -> ok_error()</c>
+ </tag>
+ <item>
+ <p>This option changes how the daemon execute exec-requests from clients. The term in <c>ok_error()</c>
+ is formatted to a string if it is a non-string type. No trailing newline is added in the ok-case but in the
+ error case.</p>
+ <p>Error texts are returned on channel-type 1 which usually are piped to <c>stderr</c> on e.g Linux systems.
+ Texts from a successful execution will in similar manner be piped to <c>stdout</c>. The exit-status code
+ is set to 0 for success and -1 for errors. The exact results presented on the client side depends on the
+ client.
+ </p>
+ <p>The option cooperates with the daemon-option <seealso marker="#daemon_opt_shell"><c>shell</c></seealso>
+ in the following way:</p>
+ <taglist>
+ <tag>1. If the exec-option is present (the shell-option may or may not be present):</tag>
+ <item>
+ <p>The exec-option fun is called with the same number of parameters as the arity of the fun,
+ and the result is returned to the client.
+ </p>
+ </item>
+
+ <tag>2. If the exec-option is absent, but a shell-option is present with the default Erlang shell:</tag>
+ <item>
+ <p>The default Erlang evaluator is used and the result is returned to the client.</p>
+ </item>
+
+ <tag>3. If the exec-option is absent, but a shell-option is present that is not the default Erlang shell:</tag>
+ <item>
+ <p>The exec-request is not evaluated and an error message is returned to the client.</p>
+ </item>
+
+ <tag>4. If neither the exec-option nor the shell-option is present:</tag>
+ <item>
+ <p>The default Erlang evaluator is used and the result is returned to the client.</p>
+ </item>
+ </taglist>
+ <p>If a custom CLI is installed (see the option <seealso marker="#daemon_opt_ssh_cli"><c>ssh_cli</c></seealso>)
+ the rules above are replaced by thoose implied by the custom CLI.
+ </p>
+ <note>
+ <p>The exec-option has existed for a long time but has not previously been documented. The old
+ definition and behaviour are retained but obey the rules 1-4 above if conflicting.
+ The old and undocumented style should not be used in new programs.</p>
+ </note>
</item>
- <tag><c><![CDATA[{ssh_cli, {channel_callback(),
+
+ <tag><marker id="daemon_opt_ssh_cli"/>
+ <c><![CDATA[{ssh_cli, {channel_callback(),
channel_init_args()} | no_cli}]]></c></tag>
<item>
<p>Provides your own CLI implementation, that is, a channel callback
module that implements a shell and command execution. The shell
read-eval-print loop can be customized, using the
- option <c>shell</c>. This means less work than implementing
- an own CLI channel. If set to <c>no_cli</c>, the CLI channels
+ option <seealso marker="#daemon_opt_shell"><c>shell</c></seealso>. This means less work than implementing
+ an own CLI channel. If <c>ssh_cli</c> is set to <c>no_cli</c>, the CLI channels
+ like <seealso marker="#daemon_opt_shell"><c>shell</c></seealso>
+ and <seealso marker="#daemon_opt_exec"><c>exec</c></seealso>
are disabled and only subsystem channels are allowed.</p>
</item>
<tag><c><![CDATA[{user_dir, string()}]]></c></tag>
--
2.16.3
