how can I override busybox builtins?

[Denys Vlasenko]

On Tuesday 12 October 2010 00:19, Stuart Longland wrote:
> On 10/11/10 22:39, Monkey D. Luffy wrote:
> > After several hours of head banging I realized that busybox uses
> > builtins instead of the binaries in PATH.
> > Why is this the default behavior?

These options are not on by default in build system.

Whoever compiled your busybox copy turned them on deliberately.

> > If the executables are in PATH it 
> > would make sense that the user wants them to be used instead.
> > Is there a way to force busybox to use the executables in $PATH
> > instead of the builtins?

IIRC in ash there is command builtin: "command foo" will run
external command foo.

> > Maybe setting a shell variable like:  BB_PREFER_BUILTINS=no
> > Note that setting the full path to the executable, eg: /usr/sbin/mount
> > (I deleted the /bin/mount), doesn't solve the problem because is it
> > used in exec scenarios.

I don't understand.
What do you refer to by the word "it" above?

 
> There's a .config option when building Busybox:
> 
>  BusyBox 1.17.1 Configuration
>  ──────────────────────────────────────────────────────────────────────
>  ┌─────────────────────── exec prefers applets ───────────────────────┐
>  │ CONFIG_FEATURE_PREFER_APPLETS:                                     │
>  │                                                                    │
>  │ This is an experimental option which directs applets about to      │
>  │ call 'exec' to try and find an applicable busybox applet  before   │
>  │ searching the PATH. This is typically done by exec'ing             │
>  │ /proc/self/exe.                                                    │
>  │ This may affect shell, find -exec, xargs and similar applets.      │
>  │ They will use applets even if /bin/<applet> -> busybox link        │
>  │ is missing (or is not a link to busybox). However, this causes     │
>  │ problems in chroot jails without mounted /proc and with ps/top     │
>  │ (command name can be shown as 'exe' for applets started this way). │
>  │                                                                    │
>  │ Symbol: FEATURE_PREFER_APPLETS [=n]                                │
>  │ Prompt: exec prefers applets                                       │
>  │   Defined at Config.in:373                                         │
>  │   Location:                                                        │
>  │     -> Busybox Settings                                            │
>  │       -> General Configuration                                     │
>  ├────────────────────────────────────────────────────────────(100%)──┤
>  │                              < Exit >                              │
>  └────────────────────────────────────────────────────────────────────┘
> 
> Not sure why exec'ing to a full path is a problem however.  IIRC that
> overrode this behaviour.

Also, turn off SH_STANDALONE.
-- 
vda