[Pdbg] [PATCH 12/13] libpdbg: Add a check if device tree is writeable

[Alistair Popple]

Reviewed-by: Alistair Popple <alistair at popple.id.au>

On Wednesday, 15 January 2020 4:19:00 PM AEDT Amitay Isaacs wrote:
> Signed-off-by: Amitay Isaacs <amitay at ozlabs.org>
> ---
>  libpdbg/device.c |  3 +++
>  libpdbg/dtb.c    | 20 ++++++++++++++++++++
>  libpdbg/target.h |  1 +
>  3 files changed, 24 insertions(+)
> 
> diff --git a/libpdbg/device.c b/libpdbg/device.c
> index 6c11836..f1c1f6b 100644
> --- a/libpdbg/device.c
> +++ b/libpdbg/device.c
> @@ -327,6 +327,9 @@ bool pdbg_target_set_property(struct pdbg_target
> *target, const char *name, cons size_t len;
>  	int ret;
> 
> +	if (!target->fdt || !pdbg_fdt_is_writeable(target->fdt))
> +		return false;
> +
>  	p = pdbg_target_property(target, name, &len);
>  	if (!p)
>  		return false;
> diff --git a/libpdbg/dtb.c b/libpdbg/dtb.c
> index 6fdce00..6e05663 100644
> --- a/libpdbg/dtb.c
> +++ b/libpdbg/dtb.c
> @@ -411,6 +411,26 @@ void *pdbg_system_fdt(void)
>  	return pdbg_dtb.system.fdt;
>  }
> 
> +static bool is_fdt_mapped(void *fdt, struct pdbg_mfile *mfile)
> +{
> +	if (mfile->fdt == fdt && mfile->fd != -1 && mfile->len != -1) {
> +		return true;
> +	}
> +
> +	return false;
> +}
> +
> +bool pdbg_fdt_is_writeable(void *fdt)
> +{
> +	bool ok;
> +
> +	ok = is_fdt_mapped(fdt, &pdbg_dtb.system);
> +	if (!ok)
> +		ok = is_fdt_mapped(fdt, &pdbg_dtb.backend);
> +
> +	return ok;
> +}
> +
>  static void close_dtb(struct pdbg_mfile *mfile)
>  {
>  	if (mfile->fd != -1 && mfile->len != -1 && mfile->fdt) {
> diff --git a/libpdbg/target.h b/libpdbg/target.h
> index 1c08363..2ecdfce 100644
> --- a/libpdbg/target.h
> +++ b/libpdbg/target.h
> @@ -79,6 +79,7 @@ extern struct list_head target_classes;
> 
>  struct pdbg_dtb *pdbg_default_dtb(void *system_fdt);
>  const char *pdbg_get_backend_option(void);
> +bool pdbg_fdt_is_writeable(void *fdt);
> 
>  struct chipop *pib_to_chipop(struct pdbg_target *target);
>  bool target_is_virtual(struct pdbg_target *target);