7.5 KiB
xmppipe: stdio over XMPP
xmppipe redirects stdin/stdout in a shell pipeline to an XMPP MUC (XEP-0045). xmppipe supports flow control using stream management (XEP-0198) and can optionally deal with overload by acting as a circuit breaker or by discarding messages.
xmppipe works with line oriented tools like grep, sed and awk by outputting each message as a newline terminated, percent-encoded string.
xmppipe can be used in shell scripts to quickly write interactive bots for monitoring systems or for sending alerts.
Usage
xmppipe [*options*]
XMPPIPE_USERNAME=me@example.com
XMPPIPE_PASSWORD="password"
xmppipe -o muc
Requirements
-
Linux: libuuid
apt-get install uuid-dev
Build
$ make
Tests
# Install bats:
# apt-get install bats
# git clone https://github.com/sstephenson/bats.git # or from git
make test
Sandboxing
xmppipe restricts itself to the operations necessary for interacting with stdio.
When the process starts, an "init" sandbox limits the process to operations required for connecting to the XMPP server. After the connection is established, a more restrictive sandbox limits operations to interacting with stdio.
The mechanism used depends on the platform. By default:
-
Linux:
- init: seccomp(2)
- stdio: seccomp(2)
-
OpenBSD:
- init: pledge(2)
- stdio: pledge(2)
-
FreeBSD:
- init: setrlimit(2)
- stdio: setrlimit(2)/capsicum(4)
-
other: setrlimit(2)
- init: setrlimit(2)
- stdio: setrlimit(2)
Selecting the sandbox can be done at compile time. For example, to use the "rlimit" sandbox:
XMPPIPE_SANDBOX=XMPPIPE_SANDBOX_RLIMIT make
If a sandbox is interfering with normal operation, please open an issue. To disable the sandbox, compile using the "null" sandbox:
XMPPIPE_SANDBOX=XMPPIPE_SANDBOX_NULL make
Options
- -u JID
- XMPP username: takes precedence over environment variable
- -p password
- XMPP password: takes precedence over environment variable
- -r resource
- XMPP resource, used as the nickname in the MUC
- -o output
- XMPP MUC name
Default: stdout-hostname-uid
- -S subject
- XMPP MUC subject
- -a address:port
- Specify the IP address and port of the XMPP server
- -d
- Discard stdin when MUC is empty
- -D
- Discard stdin and print to local stdout
- -e
- Ignore stdin EOF
- -s
- Exit when MUC is empty
- -x
- Base64 encode/decode data
- -b size
- Size of read buffer
- -I interval
- Request stream management status every interval messages
- -k seconds
- Periodically send a keepalive
- -K count
- Number of keepalive failures before exiting
- -P ms
- Poll delay
- -v
- Increase verbosity
Decoding Percent-Encoded Strings
Using bash:
decode() {
printf '%b' "${1//%/\\x}"
}
Examples
Shell Bot
An interactive XMPP bot written in the shell:
#!/bin/bash
set -e
set -u
set -o pipefail
trap cleanup 0
TMPDIR=$(mktemp -d)
in="$TMPDIR/stdin"
out="$TMPDIR/stdout"
mkfifo $in
mkfifo $out
cleanup() {
rm -rf $TMPDIR
}
decode() {
printf '%b' "${1//%/\\x}"
}
bot() {
while read line; do
IFS=:
set -- $line
if [ "$1" = "p" ]; then
decode "$line" 1>&2
echo 1>&2
elif [ "$1" = "m" ]; then
USER="$(decode ${3#*%2F})"
IFS=$OFS
MSG="$(decode ${!#})"
case $MSG in
*"has set the subject to:"*) ;;
"sudo make me a sandwich")
echo "$USER: you're a sandwich"
;;
sudo*)
echo "I'm sorry, $USER. I'm afraid I can't do that."
;;
uptime)
uptime
;;
exit)
echo "exiting ..."
exit 0
;;
*)
echo "$@"
;;
esac
fi
done < $out
}
bot > $in &
xmppipe "$@" <$in >$out
SSH over XMPP
# Server: has access to the destination SSH server
# ssh-over-xmpp server <conference> <IP address> <port>
ssh-over-xmpp server sshxmpp 1.2.3.4 22
## Client: has access to the XMPP server
ssh -o ProxyCommand="ssh-over-xmpp client sshxmpp" 127.0.0.1
Stream Events from Riemann
This example will stream events from a query to an XMPP MUC using Riemann's SSE interface. The events are written to a named pipe to avoid buffering.
mkfifo riemann
curl -s --get --data subscribe=true \
--data-urlencode 'query=(service ~= "^example")' \
http://example.com:80/index < /dev/null > riemann &
xmppipe -o "muc" -d -vv -S "riemann events" < riemann
Mirror a terminal session using script(1)
- user
#!/bin/bash
MUC=console
TMPDIR=$(mktemp -d)
FIFO=$TMPDIR/console
mkfifo $FIFO
stty cols 80 rows 24
(cat $FIFO | xmppipe -r user -o $MUC -x) > /dev/null 2> $TMPDIR/stderr &
script -q -f $FIFO
- viewers
#!/bin/bash
decode() {
printf '%b' "${1//%/\\x}"
}
stty cols 80 rows 24
xmppipe -r viewer -o console -x | while read l; do
IFS=:
set -- $l
if [ "$1" = "m" ]; then
decode $5
fi
done
Mirror a terminal session to a web page
Environment Variables
-
XMPPIPE_USERNAME: XMPP jid
-
XMPPIPE_PASSWORD: XMPP password
Format
Each message is terminated by a new line. Message fields are separated by ":" and percent encoded.
Presence
p:<available|unavailable>:<to jid>:<from jid>
Example:
p:available:test@muc.example.com/xmppipe:occupant@example.com/1234
Message
m:<chat|groupchat>:<from jid>:<to jid>:<message body>
Example:
m:groupchat:test@muc.example.com/mobile:user1@example.com/1234:Hello
m:chat:user1@example.com/mobile:user2@example.com:Message%20goes%20here
Compatibility
Tested with ejabberd and mongooseim.
Security Considerations
libstrophe does not verify the TLS server certificates. Sessions can be MITM'ed.
libstrophe has support for TLS certificate verification on a branch.
libmesode supports TLS certificate verification.
License
Copyright (c) 2015-2017, Michael Santos michael.santos@gmail.com
Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
TODO
-
Support TLS certificate verification
Switch to using libmesode
-
support XEP-0384: OMEMO Encryption