Re: handling script/init errors

[Sascha Hauer <s.hauer@pengutronix.de>]

On Wed, Nov 13, 2013 at 05:51:28PM +1100, Marc Reilly wrote:
> Hi,
> 
>  
> > hush used to interpret return values from commands < 0 as 'exit'. This
> > 
> > changed with this commit:
> > | commit 16edced39ecf4c316179b72c01af249f85b36218
> > | Author: Sascha Hauer <s.hauer@pengutronix.de>
> > | Date:   Fri Aug 10 12:40:01 2012 +0200
> > | 
> > |     hush: Make exit a shell builtin
> > |     
> > |     'exit' used to do its job by returning value < 0. This is a sign
> > |     for hush that 'exit' is executed. This has problems:
> > |     
> > |     - Often commands accidently return a negative value. This causes
> > |     
> > |       the shell to exit.
> > |     
> > |     - execute_binfmt returns a negative value when it does not find
> > |     
> > |       a binary to execute. This again causes the shell to exit.
> > |       Returning a negative error value seems to be the right thing
> > |       to do, but catching this in the shell would mean that the exit
> > |       command does not work anymore.
> > |     
> > |     - if called without arguments exit is supposed to return the code
> > |     
> > |       of the last command. As a command exit has no access to this code.
> > |     
> > |     This patch changes exit to be a builtin and also fixes the last return
> > |     code problem. While at it, update the help text.
> > |     
> > |     Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> > 
> > Probably the patch above introduced problems of its own fixed in later
> > commits, so if your device is in production you're better off looking
> > at i2c_write. I assume it returns a negative error value under some
> > circumstances. Let it return 1 instead.
> 
> Thanks!
> 
> In commands/i2c.c: I changed all "return -ENODEV;" to "return COMMAND_ERROR" 
> and the scripts keep executing.
> 
> This fixed it for our version, I'll check if its relevant to current version 
> and send in a patch soon.

This shouldn't be needed in current barebox. The commands now can return
negative error values without causing the shell to exit.

Sascha

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