xtrace1

Usage

Overview

Xtrace fakes an X server and forwards all connections to a real X server, displaying the communication between clients in (well, theoretically) human readable form. If a command is given, xtrace executes the named command with $DISPLAY set to the faked X server. If that command exits before any connections are made, xtrace exits immediately unless -W is specified.

Options

-I directory

Look into directory for protocol description files. (i.e. the directory where the .proto files can be found).

-s | --stopwhendone (default)

Terminate when all forwarded clients have disconnected. (Or when a program was run once the program has finished and all connections are closed).

-k | --keeprunning

If all clients disconnected, wait for new ones to connect.

-W | --waitforclient

Do not stop when the started program terminates before any connection was made. (Might be necessary if the program forks to background).

-d name | --display name

Forward connections to the X server specified by name instead of the one specified by the environment variable DISPLAY.

-D name | --fakedisplay name

Fake display name instead of $FAKEDISPLAY or :9 respectively.

-f filename | --authfile filename

Add an -f filename to the arguments for all calls to xauth to get the authentication tokens of the X server to connect to.

-F filename | --newauthfile filename

Add an -f filename to the arguments for all calls to xauth to save the authentication tokens to connect to the faked X server.

-c | --copyauthentication (default)

Copy the authentication tokens for the X server to connect to so that clients connecting to our fake server will use them.

The commands run are roughly equivalent to: xauth add $FAKEDISPLAY . `xauth list $DISPLAY | awk '$2=="MIT-MAGIC-COOKIE-1" {print $3}'`

Not that only MIT-MAGIC-COOKIE-1 tokens are copied as xtrace does not yet support to change the authentication tokens so that XDM-AUTHORIZATION-1 would be possible.

-n | --nocopyauthentication

Do not call xauth and do fiddle with authentication tokens but leave that to the user to handle.

-e | --denyextensions

Modify all server replies to say there are no extensions available. (As xtrace does supports only a small number of extensions anyway and calls all extended requests "unknown" and all replies to such requests "unexpected").

-w | --readwritedebug

Print how many bytes are read and/or written when.

-m count | --maxklistlength count

Print only the first count many elements of all lists.

-i | --interactive

Only sent requests from the client to the server after interactive confirmation. Confirmation is given by pressing enter or a number followed by enter via stdin. This can give funny results when multiple clients are tunneled.

-o | --outfile filename

Dump output into filename instead of stdout.

-b | --buffered

Do not write every line on its own but wait until buffers are full. Speeds up things a little bit when outputting to a file. Not very useful at all together with -i.

--timestamps

Print a timestamp before each line.

Note that the time a packet is printed is between the time a packet is received and the time a packet is sent, but it gives no other information than that.

--relative-timestamps

Print a timestamp relative to the beginning of the connection before each line.

Note that the time a packet is printed is between the time a packet is received and the time a packet is sent, but it gives no other information than that.

--monotonic-timestamps

Print a CLOCK_MONOTONIC (see clock_gettime(3)) timestamp each time a package is printed. This is likely to be the uptime of your system.

Note that the time a packet is printed is between the time a packet is received and the time a packet is sent, but it gives no other information than that.

--print-offsets

Print offsets of all fields (useful to debug nested lists in protocol descriptions)

--print-counts

Print counts (useful to debug lists in protocol descriptions)

Environment

DISPLAY

Without --display the content of this variable is used to determine the server to connect to. (And without -n given to xauth to get the authentication tokens for this display.)

FAKEDISPLAY

Without --fakedisplay the content of this variable is used to determine how to listen for clients. (And without -n given to xauth to set the authentication tokens for this display.) If neither is given, xtrace will try :9

XAUTHORITY

Without -n and without -f or -F your xauth program will most likely look into this variable for the file to get/save the authentication tokens from/into. If this is not set it will most likely use $HOME/.Xauthority.