On Thu, Aug 08, 2024 at 05:37:47PM +0200, Tobias Heider wrote:
> From: Tobias Heider <m...@tobhe.de>
>
> With this change it is possible to access properties in subnodes
> using the -n argument as in 'fdtdump -n chosen -p stdout-path'.
> It is also possible to access deeper nested properties by passing
> a path separated by '/' such as 'fdtdump -n path/to/node'
>
> Signed-off-by: Tobias Heider <tobias.hei...@canonical.com>
> ---
> docs/grub.texi | 6 +++++-
> grub-core/loader/efi/fdt.c | 32 +++++++++++++++++++++++++-------
> 2 files changed, 30 insertions(+), 8 deletions(-)
>
> diff --git a/docs/grub.texi b/docs/grub.texi
> index a050dc0fc..06d41fa03 100644
> --- a/docs/grub.texi
> +++ b/docs/grub.texi
> @@ -4909,13 +4909,17 @@ such as @code{if} and @code{while} (@pxref{Shell-like
> scripting}).
> @subsection fdtdump
>
> @deffn Command fdtdump @
> + [@option{--node} @var{node}] @
> [@option{--prop} @var{prop}] @
> [@option{--set} @var{variable}]
> Retrieve device tree information.
>
> The @command{fdtdump} command returns the value of a property in the device
> tree provided by the firmware. The @option{--prop} option determines which
> -property to select.
> +property to select. By default fdtdump returns properties from the root of
> +the device tree unless a different @var{node} is specified with the
> +@option{--node} option. @var{node} can be the name of a root subnode or a
> path
> +from the root separated by '/' for deeper nested nodes.
>
> The default action is to print the value of the requested field to the
> console,
> but a variable name can be specified with @option{--set} to store the value
> diff --git a/grub-core/loader/efi/fdt.c b/grub-core/loader/efi/fdt.c
> index b43ff730d..7319af0e9 100644
> --- a/grub-core/loader/efi/fdt.c
> +++ b/grub-core/loader/efi/fdt.c
> @@ -40,6 +40,7 @@ static void *fdt;
> sizeof (FDT_SIZE_CELLS_STRING))
>
> static const struct grub_arg_option options_fdtdump[] = {
> + {"node", 'n', 0, N_("Device tree node."), N_("node"), ARG_TYPE_STRING},
> {"prop", 'p', 0, N_("Get property."), N_("prop"), ARG_TYPE_STRING},
> {"set", '\0', 0, N_("Store the value in the given variable name."),
> N_("variable"), ARG_TYPE_STRING},
> @@ -184,17 +185,34 @@ grub_cmd_fdtdump (grub_extcmd_context_t ctxt,
> {
> struct grub_arg_list *state = ctxt->state;
> const unsigned char *value = NULL;
> - char *str;
> + char *node_name, *str, *p;
> void *fw_fdt;
> grub_uint32_t len;
> + int node = 0;
>
> fw_fdt = grub_efi_get_firmware_fdt ();
> if (fw_fdt == NULL)
> - return grub_error (GRUB_ERR_IO,
> - N_("No device tree found"));
> + return grub_error (GRUB_ERR_IO, N_("No device tree found"));
Nice, but you should mention the patch does some cleanup.
> if (state[0].set)
> - value = grub_fdt_get_prop (fw_fdt, 0, state[0].arg, &len);
> + {
> + node_name = state[0].arg;
> + while ((p = grub_strchr (node_name, '/')) != NULL) {
> + *p = '\0';
> +
> + node = grub_fdt_find_subnode (fw_fdt, node, node_name);
> + if (node < 1)
> + return grub_error (GRUB_ERR_IO, N_("failed to find node in fdt"));
> +
> + node_name = ++p;
> + }
> + node = grub_fdt_find_subnode (fw_fdt, node, node_name);
> + if (node < 1)
> + return grub_error (GRUB_ERR_IO, N_("failed to find node in fdt"));
> + }
> +
> + if (state[1].set)
> + value = grub_fdt_get_prop (fw_fdt, node, state[1].arg, &len);
>
> if (value == NULL)
> return grub_error (GRUB_ERR_OUT_OF_RANGE,
> @@ -204,8 +222,8 @@ grub_cmd_fdtdump (grub_extcmd_context_t ctxt,
> if (str == NULL)
> return grub_error (GRUB_ERR_IO, N_("Failed to print string"));
>
> - if (state[1].set)
> - grub_env_set (state[1].arg, str);
> + if (state[2].set)
> + grub_env_set (state[2].arg, str);
> else
> grub_printf ("%s", str);
>
> @@ -220,7 +238,7 @@ GRUB_MOD_INIT (fdt)
> {
> cmd_fdtdump =
> grub_register_extcmd ("fdtdump", grub_cmd_fdtdump, 0,
> - N_("[-p] [--set variable]"),
> + N_("[-n] [-p] [--set variable]"),
I think short options should be added to the GRUB doc too.
Daniel
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