How to edit a *nix system file using Ruby's File.open command?

Question

In my CMS (Rails 4), I need to let a user make CRUD processes on CIFS mount points. In order to have a permanent CIFS mount on a CentOS (6) system, I need to edit the /etc/fstab file and update the mount list with the sudo mount -a command. When I try to open /etc/fstab file with File.open:

File.open("/etc/fstab", "a") do |f|
  f.puts "\n test"
end

I get this error:

Errno::EACCES: Permission denied - /etc/fstab

It's normal because /etc/fstab file belongs to the root user. Is there a way to open a file as super user? At the other hand, I'm open to different ideas. My requirement is to edit the fstab file from inside of my application.

score 1 · Accepted Answer · answered Mar 03 '14 at 12:55

1

See this answer in the ruby forum:

Start your script using
sudo ruby myscript.rb
You can't gain root privileges mid-script, short of
system("sudo ruby anotherscript.rb")

answered Mar 03 '14 at 12:55

Uri Agassi

36,848
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What If I need to use dynamic parameters in that script? :\ I need to use `params[:path]` parameter. – scaryguy Mar 03 '14 at 14:49
`system("sudo ruby anotherscript.rb #{params[:path]}")`, http://stackoverflow.com/a/4244651/1120015 – Uri Agassi Mar 03 '14 at 14:52

score 0 · Answer 2 · answered Mar 03 '14 at 12:57

0

This one is tricky but you could add your Web user to the sudoers list and submit the sudo password when trying to edit the file. Make sure your connection is secured via https

answered Mar 03 '14 at 12:57

lsaffie

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How to edit a *nix system file using Ruby's File.open command?

2 Answers2