I'd like to programmatically check if someone has their SSH keys set up correctly for GitHub. I understand that I can use `ssh -T git#github.com` in Ruby. However, I'd like to keep the ssh output in a variable.
My current code is:
github_response = `ssh -T git#github.com`
unless github_response.start_with?('Hi')
puts 'Please set up your GitHub ssh keys'
end
`ssh -T git#github.com` outputs the response (starting with "Hi"). However the github_response variable is nil.
How can I assign the output of `ssh -T git#github.com` to github_response?
Your example failed because the Hi xxx! You've successfully authenticated.... message is not from stdout, but stderr.
> require 'open3'
=> true
> stdin, stdout, stderr, wait_thr = Open3.popen3('ssh -T git#github.com')
=> [#<IO:fd 8>, #<IO:fd 9>, #<IO:fd 11>, #<Thread:0x007f89ee1149a8 sleep>]
> stdout.gets
=> nil
> stderr.gets
=> "Hi halfelf! You've successfully authenticated, but GitHub does not provide shell access.\n"
You could add -v for verbose output, it will then dump much of the connection info to stdout. From that log you can scrape to find whether the server accepted any of the keys the ssh client offered
Related
I am trying to parse rsyslog logs. For this i am sending all my logs to socat which is then sending them to Unix Domain Socket. That socket is created via perl script which is listening on that socket to parse logs.
My bash script to which rsyslog is sending all log is
if [ ! `pidof -x log_parser.pl` ]
then
./log_parser.pl & 1>&1
fi
if [ -S /tmp/sock ]
then
/usr/bin/socat -t0 -T0 - UNIX-CONNECT:/tmp/sock 2>> /var/log/socat.log
fi
/tmp/sock is created using perl script log_parser.pl which is
use IO::Socket::UNIX;
sub socket_create {
$socket_path = '/tmp/sock';
unlink($socket_path);
$listner = IO::Socket::UNIX->new(
Type => SOCK_STREAM,
Local => $socket_path,
Listen => SOMAXCONN,
Blocking => 0,
)
or die("Can't create server socket: $!\n");
$socket = $listner->accept()
or die("Can't accept connection: $!\n");
}
socket_create();
while(1) {
chomp($line=<$socket>);
print "$line\n";
}
There is this error i am getting from socat which is
2015/02/24 11:58:01 socat[4608] E connect(3, AF=1 "/tmp/sock", 11): Connection refused
I am no champion in sockets so i am not able to understand what is this. Please help. Thanks in advance.
The main issue is that when i kill my perl script then bash script is suppose to call it again and start it.
What actually happening is that sript is started but socat is not started instead it give this error and never start.
I can duplicate your error if I don't run your perl program before trying to use socat. Here is what works for me:
1) my_prog.pl:
use strict;
use warnings;
use 5.016;
use Data::Dumper;
use IO::Socket::UNIX;
my $socket_path = '/tmp/sock';
unlink $socket_path;
my $socket = IO::Socket::UNIX->new(
Local => $socket_path,
Type => SOCK_STREAM,
Listen => SOMAXCONN,
) or die "Couldn't create socket: $!";
say "Connected to $socket_path...";
my $CONN = $socket->accept()
or die "Whoops! Failed to open a connection: $!";
{
local $/ = undef; #local -> restore previous value when the enclosing scope, delimited by the braces, is exited.
#Setting $/ to undef puts file reads in 'slurp mode' => whole file is considered one line.
my $file = <$CONN>; #Read one line.
print $file;
}`
2) $ perl my_prog.pl
3) socat -u -v GOPEN:./data.txt UNIX-CONNECT:/tmp/sock
The -u and -v options aren't necessary:
-u Uses unidirectional mode. The first address is only used for
reading, and the second address is only used for writing (exam-
ple).
-v Writes the transferred data not only to their target streams,
but also to stderr. The output format is text with some conver-
sions for readability, and prefixed with "> " or "< " indicating
flow directions.
4) You can also do it like this:
cat data.txt | socat STDIN UNIX-CONNECT:/tmp/sock
Pipe stdout of cat command to socat, then list STDIN as one of socat's files.
Response to comment:
This bash script works for me:
#!/usr/bin/env bash
echo 'bash script'
../pperl_programs/my_prog.pl &
sleep 1s
socat GOPEN:./data.txt UNIX-CONNECT:/tmp/sock
It looks like the perl script doesn't have enough time to setup the socket before socat tries to transfer data.
I have a password like 'X&Y' and I am trying to run a Ruby script that opens an SSH session, but the script breaks at the & character like :
*server: X
*server: bash: Y: command not found
Escaping the character like & doesn't help either. Ideas appreciated!
The code where it happens is at the ssh.exec:
pass="X\&Y"
Net::SSH.start( host_name, user, :password => pass ) do |ssh|
#do stuff
command = "sudo -S rm file"
cmd = "#{pass}|#{command}"
ssh.exec(cmd) do |ch, stream, data|
puts "*server:" + data.inspect
end
end
You can use ssh like without & getting any special meaning:
ssh -t -t user#localhost "echo 'abc&def'"
abc&def
Connection to localhost closed.
I'm using IO.popen to start a subprocess, but I only get the result of everything that happened in the time it took for the subprocess to run (sometimes 5 minutes or whatever) when the subprocess exits. I really need to be able to see everything the subprocess writes to stderr and stdout as-and-when it happens.
So far I could not find anything that works like this, but I'm sure it's possible.
if you need to get output in real time i would recommend to use stdlib PTY instead of popen
something like this:
require 'pty'
cmd = 'echo a; sleep 1; cat /some/file; sleep 1; echo b'
PTY.spawn cmd do |r, w, pid|
begin
r.sync
r.each_line { |l| puts "#{Time.now.strftime('%M:%S')} - #{l.strip}" }
rescue Errno::EIO => e
# simply ignoring this
ensure
::Process.wait pid
end
end
exit "#{cmd} failed" unless $? && $?.exitstatus == 0
> 33:36 - a
> 33:37 - cat: /some/file: No such file or directory
> 33:38 - b
this way you get output instantly, just as in terminal
You might want to use Open3.popen3 from standard library, it gives access to stdin, stdout, and stderr as streams.
When I do something like the following:
output = `identify some_file`
output == "Output of identify"
But when...
output = `identify non_existant_file`
output != "Error output of identify"
How can I get the error output of system calls?
I found out the answer. The output is being sent to stderr. So I can just add the following at the end of the command to redirect stderr to stdout:
output = `identify any_file 2>&1`
output == "Error or output of identify"
Here is the explanation of this witchcraft
You may use Open3.popen3.
http://www.ruby-doc.org/stdlib-1.9.3/libdoc/open3/rdoc/Open3.html#method-c-popen3
popen3(*cmd, &block) click to toggle source
Open stdin, stdout, and stderr streams and start external executable.
Open3.popen3([env,] cmd... [, opts]) {|stdin, stdout, stderr, wait_thr|
pid = wait_thr.pid # pid of the started process.
...
exit_status = wait_thr.value # Process::Status object returned.
}
I'm trying to write a little lib which generates a keypair using open4, is this the best way of dealing with system calls with multiple prompts?
require 'rubygems'
require 'open4'
Open4::popen4("sh") do |pid, stdin, stdout, stderr|
stdin.puts "openssl genrsa -des3 -out tmp_priv.pem 2048"
stdin.puts "1234"
stdin.puts "1234"
stdin.close
end
Open4::popen4("sh") do |pid, stdin, stdout, stderr|
stdin.puts "openssl rsa -in tmp_priv.pem -out tmp_public.pem -outform PEM -pubout"
stdin.puts "1234"
stdin.close
end
Open4::popen4("sh") do |pid, stdin, stdout, stderr|
stdin.puts "cat tmp_priv.pem tmp_public.pem >> tmp_keypair.pem"
stdin.close
end
I'm not sure your example is going to do what you want. If run as in your question openssl is going to open /dev/tty and it will end up prompting the user despite the pipe. It won't see the 1234.
If instead you run:
openssl genrsa -passout stdin ...
then in that case it will read stdin but it will only need the output file password once. And to answer the question you asked, yes, that's a good way, though it's not a system call.
It's also quite rare on Unix-like systems to need to fake up program input in the first place. You might want to reread the openssl(1ssl) and genrsa(1ssl) man pages; they will note various different password source options.
I've found that calling popen4 with the "block" syntax just doesnt work.
But what i've found works is to do this:
harp: > cat sample/simple.rb
require "open4"
pid, stdin, stdout, stderr = Open4:open4 "sh"
stdin.puts "echo 42.out"
stdin.puts "echo 42.err 1>&2"
stdin.close
ignored, status = Process::waitpid2 pid
puts "pid : #{ pid }"
puts "stdout : #{ stdout.read.strip }"
puts "stderr : #{ stderr.read.strip }"
puts "status : #{ status.inspect }"
puts "exitstatus : #{ status.exitstatus }"
harp: > ruby sample/simple.rb
pid : 17273
stdout : 42.out
stderr : 42.err
status : #<Process::Status: pid=17273,exited(0)>
exitstatus : 0
Which will work with passing the stdin. But at the same time, also giving back the stdout and stderr. And it avoided the exception:
in 'write': closed stream (IOError)
too. So this seems the best way to use popen4.
For other examples, see the README:
http://github.com/ahoward/open4