[Pdbg] [PATCH 1/2] libpdbg: Check if scom controllers are exposed

[Joel Stanley]

On 8 May 2018 at 09:41, Rashmica Gupta <rashmica.g at gmail.com> wrote:
> If CONFIG_SCOM_DEBUGFS is not set in the running kernel then
> the scom controllers are not exposed and so using getscom
> won't work. Add check for /sys/kernel/debug/powerpc/scom to
> give a more useful error message.
>
> Signed-off-by: Rashmica Gupta <rashmica.g at gmail.com>
> ---
>  libpdbg/host.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/libpdbg/host.c b/libpdbg/host.c
> index f43b355..cf71e5c 100644
> --- a/libpdbg/host.c
> +++ b/libpdbg/host.c
> @@ -95,6 +95,13 @@ static int host_pib_probe(struct pdbg_target *target)
>         if (chip_id == -1)
>                 goto out;
>
> +       /* This check should probably be done earlier */
> +       if (access(XSCOM_BASE_PATH, F_OK) == -1)
> +       {
> +               fprintf(stderr, "Can not access %s. ", XSCOM_BASE_PATH);
> +               fprintf(stderr, "Is CONFIG_SCOM_DEBUGFS set?\n");

We're in the same boat if the user runs without sufficient permission
(debugfs is usually not readable for normal users).

Perhaps the message should take that into account?

Cheers,

Joel