Why start-stop-daemon needs privileges?

Question

I am writing a Daemon and I want to use start-stop-daemon command to do it but, when I use it in the command line I get :

The command could not be located because '/sbin' is not included in the PATH environment variable.
This is most likely caused by the lack of administrative privileges associated with your user account.
start-stop-daemon: command not found

but when i use it with sudo it run perfect but i need it to run in daemon and i think it is not good to use sudo in bash script in daemon something like :

sudo start-stop-daemon --start --background ...

Isn't it? When I deleted sudo from it it gave me command not found. How can i fix it? if it is wrong to use sudo in daemon.

You probably need to explain what you expect the command to do ... as in, what daemon are you trying to start, and what user do you expect to own it. — ams, Sep 01 '14 at 16:36
If you have a daemon which can do something useful while running totally unprivileged, why do you want to use `start-stop-daemon`? — tripleee, Sep 01 '14 at 16:52
@ams no i am trying different solutions base on the comments and answers.that is why i reply late. — user3996615, Sep 01 '14 at 17:26

score 1 · Answer 1 · answered Sep 01 '14 at 16:37

That depends on your settings in '/etc/sudoers'.

If the environment is reset (default), the following path definition 'secure_path' contains /sbin (excerpt from Ubuntu '/etc/sudoers'):

Defaults        env_reset
Defaults        secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"

Otherwise you need to provide the full program path

/sbin/start-stop-daemon

score 1 · Accepted Answer · answered Sep 01 '14 at 16:54

start-stop-daemon can also set the user ID for the daemon process.

That said, you'd generally use start-stop-daemon from a script in /etc/rc.d, which is run with root privileges either from the init system that is being used this week (sysvinit, upstart, systemd, ...) and/or from the service(8) command.

So, if a user should be able to start/stop the service (which is a rather uncommon scenario), you'd use the sudoers file to grant them access to the service command, with the name of your service as a mandatory first argument.

In general though, write your service so it can be simply started at boot or during installation, and used by users as long as it's running. If the user needs to be able to start and stop instances of the service, then your daemon is in the business of managing instances, and the instance manager should be continually running, and users then contact this service via a socket (so users don't need sudo at all, which would make the lives of many administrators who don't install sudo quite a bit easier).

Why start-stop-daemon needs privileges?

2 Answers2