Re: [PATCH v3 5/6] common/config: Introduce _exit wrapper around exit command

[Ritesh Harjani (IBM) <ritesh.list@gmail.com>]

"Nirjhar Roy (IBM)" <nirjhar.roy.lists@gmail.com> writes:

> We should always set the value of status correctly when we are exiting.
> Else, "$?" might not give us the correct value.
> If we see the following trap
> handler registration in the check script:
>
> if $OPTIONS_HAVE_SECTIONS; then
>      trap "_kill_seq; _summary; exit \$status" 0 1 2 3 15
> else
>      trap "_kill_seq; _wrapup; exit \$status" 0 1 2 3 15
> fi
>
> So, "exit 1" will exit the check script without setting the correct
> return value. I ran with the following local.config file:
>
> [xfs_4k_valid]
> FSTYP=xfs
> TEST_DEV=/dev/loop0
> TEST_DIR=/mnt1/test
> SCRATCH_DEV=/dev/loop1
> SCRATCH_MNT=/mnt1/scratch
>
> [xfs_4k_invalid]
> FSTYP=xfs
> TEST_DEV=/dev/loop0
> TEST_DIR=/mnt1/invalid_dir
> SCRATCH_DEV=/dev/loop1
> SCRATCH_MNT=/mnt1/scratch
>
> This caused the init_rc() to catch the case of invalid _test_mount
> options. Although the check script correctly failed during the execution
> of the "xfs_4k_invalid" section, the return value was 0, i.e "echo $?"
> returned 0. This is because init_rc exits with "exit 1" without
> correctly setting the value of "status". IMO, the correct behavior
> should have been that "$?" should have been non-zero.
>
> The next patch will replace exit with _exit.
>
> Signed-off-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
> Reviewed-by: Dave Chinner <dchinner@redhat.com>
> ---
>  common/config | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/common/config b/common/config
> index 79bec87f..eb6af35a 100644
> --- a/common/config
> +++ b/common/config
> @@ -96,6 +96,14 @@ export LOCAL_CONFIGURE_OPTIONS=${LOCAL_CONFIGURE_OPTIONS:=--enable-readline=yes}
>  
>  export RECREATE_TEST_DEV=${RECREATE_TEST_DEV:=false}
>  
> +# This functions sets the exit code to status and then exits. Don't use
> +# exit directly, as it might not set the value of "status" correctly.

...as it might not set the value of "$status" correctly, which is used
as an exit code in the trap handler routine set up by the check script.

> +_exit()
> +{
> +	status="$1"
> +	exit "$status"
> +}
> +

I agree with Darrick’s suggestion here. It’s safer to update status only
when an argument is passed - otherwise, it’s easy to trip over this.

Let’s also avoid defaulting status to 0 inside _exit(). That way, if the
caller forgets to pass an argument but has explicitly set status
earlier, we preserve the intended value.

We should update _exit() with... 

test -n "$1" && status="$1"

-ritesh


>  # Handle mkfs.$fstyp which does (or does not) require -f to overwrite
>  set_mkfs_prog_path_with_opts()
>  {
> -- 
> 2.34.1