* NEWS: Add entry for stdio gdbserver.

	gdbserver/
	* linux-low.c (linux_create_inferior): If stdio connection,
	redirect stdin from /dev/null, stdout to stderr.
	* remote-utils.c (remote_is_stdio): New static global.
	(remote_connection_is_stdio): New function.
	(remote_prepare): Handle stdio connection.
	(remote_open): Ditto.
	(remote_close): Don't close stdin for stdio connections.
	(read_prim,write_prim): New functions.  Replace all calls to
	read/write to these.
	* server.c (main): Watch for "-" argument.  Move call to
	remote_prepare before start_inferior.
	* server.h (STDIO_CONNECTION_NAME): New macro.
	(remote_connection_is_stdio): Declare.

	doc/
	* gdb.texinfo (Server): Document -/stdio argument to gdbserver.

	testsuite/
	* lib/gdbserver-support.exp (gdb_target_cmd): Recognize stdio
	gdbserver output.
	(gdbserver_default_get_remote_address): New function.
	(gdbserver_start): Call gdb,get_remote_address to compute argument
	to "target remote" command.

2 files changed, 25 insertions, 2 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index e8ff5c8c46..8451302973 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,7 @@
+2011-12-16  Doug Evans  <dje@google.com>
+
+	* gdb.texinfo (Server): Document -/stdio argument to gdbserver.
+
 2011-12-16  Phil Muldoon  <pmuldoon@redhat.com>
 
 	* gdb.texinfo (Python Commands): Remove "maint set/show print
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 4787b82d19..4a7ae6eba6 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -16766,8 +16766,10 @@ syntax is:
 target> gdbserver @var{comm} @var{program} [ @var{args} @dots{} ]
 @end smallexample
 
-@var{comm} is either a device name (to use a serial line) or a TCP
-hostname and portnumber.  For example, to debug Emacs with the argument
+@var{comm} is either a device name (to use a serial line), or a TCP
+hostname and portnumber, or @code{-} or @code{stdio} to use
+stdin/stdout of @code{gdbserver}.
+For example, to debug Emacs with the argument
 @samp{foo.txt} and communicate with @value{GDBN} over the serial port
 @file{/dev/com1}:
 
@@ -16796,6 +16798,23 @@ conflicts with another service, @code{gdbserver} prints an error message
 and exits.}  You must use the same port number with the host @value{GDBN}
 @code{target remote} command.
 
+The @code{stdio} connection is useful when starting @code{gdbserver}
+with ssh:
+
+@smallexample
+(gdb) target remote | ssh -T hostname gdbserver - hello
+@end smallexample
+
+The @samp{-T} option to ssh is provided because we don't need a remote pty,
+and we don't want escape-character handling.  Ssh does this by default when
+a command is provided, the flag is provided to make it explicit.
+You could elide it if you want to.
+
+Programs started with stdio-connected gdbserver have @file{/dev/null} for
+@code{stdin}, and @code{stdout},@code{stderr} are sent back to gdb for
+display through a pipe connected to gdbserver.
+Both @code{stdout} and @code{stderr} use the same pipe.
+
 @subsubsection Attaching to a Running Program
 @cindex attach to a program, @code{gdbserver}
 @cindex @option{--attach}, @code{gdbserver} option