How can I do a linux mount in a programmatic way?

Ruby
1

If I do something like system('sudo mount … ') then I don’t really
get any error codes back to see what happened because I just get the
sudo return code here. Is there a way to do this like a library call
in ruby ?

2

El Martes, 27 de Octubre de 2009, Jedrin
escribió:> If I do something like system('sudo mount … ') then I don’t really

get any error codes back to see what happened because I just get the
sudo return code here. Is there a way to do this like a library call
in ruby ?

Use open4 (gem install open4):

require “open4”

pid, stdin, stdout, stderr = Open4::popen4(“sudo mount…”)
ignored, status = Process::waitpid2 pid

if status.to_i != 0
puts “Error: Command returned #{status.to_i}”"
end

You can also inspect the output and error output reading stdout and
stderr
(they are IO objects, no strings).

3

Jedrin wrote:

If I do something like system('sudo mount … ') then I don’t really
get any error codes back to see what happened because I just get the
sudo return code here.

I think you should get the exit status of the program which sudo ran:

$ cat xxx.sh
exit 123
$ irb --simple-prompt

%x{sudo ./xxx.sh}
=> “”

$?
=> #<Process::Status: pid=28583,exited(123)>

$?.exitstatus
=> 123

[Ubuntu Hardy, sudo 1.6.9p10-1ubuntu3.5]

Otherwise, I don’t know if there’s a way to call the mount API directly
from ruby.

Even if there was, remember that it wouldn’t work unless the ruby script
itself were running as root. That is: if you need ‘sudo’ to get root as
in your original example, then it’s always going to be in a separate
process.