Le ven. 9 mai 2025, 13:15, khaalid cali <khaliidca...@gmail.com> a écrit :
> From: khaalid <khaliidca...@gmail.com>
>
> This command is intended to print or dump all UEFI runtime services.
> The structure will look like efivar tool, since visually most people are
> familiar with it. If the variable content is string then dump it as
> string, otherwise for non string variables print them as raw hex; just
> the way efivar command does.
>
> Signed-off-by: khaalid <khaliidca...@gmail.com>
>
Please use correct legal name in sign off.
> ---
> grub-core/Makefile.core.def | 6 ++
> grub-core/commands/efi/efivar.c | 150 ++++++++++++++++++++++++++++++++
> 2 files changed, 156 insertions(+)
> create mode 100644 grub-core/commands/efi/efivar.c
>
> diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
> index f70e02e69..ef3dc2dd0 100644
> --- a/grub-core/Makefile.core.def
> +++ b/grub-core/Makefile.core.def
> @@ -840,6 +840,12 @@ module = {
> enable = efi;
> };
>
> +module = {
> + name = efivar;
> + efi = commands/efi/efivar.c;
> + enable = efi;
> +};
> +
> module = {
> name = blocklist;
> common = commands/blocklist.c;
> diff --git a/grub-core/commands/efi/efivar.c
> b/grub-core/commands/efi/efivar.c
> new file mode 100644
> index 000000000..8d81e01ab
> --- /dev/null
> +++ b/grub-core/commands/efi/efivar.c
> @@ -0,0 +1,150 @@
> +/* efivar.c - dump runtime uefi variables. */
> +/*
> + * GRUB -- GRand Unified Bootloader
> + * Copyright (C) 2009 Free Software Foundation, Inc.
>
The date is wrong
>
> +#include <grub/dl.h>
> +#include <grub/misc.h>
> +#include <grub/command.h>
> +#include <grub/charset.h>
> +#include <grub/efi/efi.h>
> +#include <grub/efi/api.h>
> +
> +GRUB_MOD_LICENSE ("GPLv3+");
> +
> +
> +/* Check if the data looks like UTF-16LE text */
> +static inline int
> +is_likely_utf16_string(grub_uint8_t *data, grub_size_t len)
> +{
> + if (len < 4) return 0;
> + for (grub_size_t i = 0; i < len; i += 2) {
> + if (data[i] == 0 && data[i+1] == 0) return 1; // Null terminator
> in UTF-16
> + if (data[i+1] != 0 && data[i+1] != 0x20) return 0; // High byte
> must be 0 or space-like
> + }
> + return 1;
> +}
>
This function is weird. What do you mean by space-like? Why null terminator
inside the string makes it "UTF-16 like"? An array 00 00 00 00 00 FF FF 00
is clearly non-UTF-16 yet this function returns 1
> +
> +static void
> +get_variable_data(const char *variable_name, grub_guid_t *variable_guid)
> +{
>
This is a dump function. Not a getter.
> + grub_efi_status_t status;
> + grub_efi_uint32_t attributes;
> + grub_size_t data_size;
> + grub_uint8_t *data;
> +
> + status = grub_efi_get_variable_with_attributes(variable_name,
> variable_guid,
> + &data_size, (void
> **)&data, &attributes);
> + if (status != GRUB_EFI_SUCCESS)
> + {
> + grub_error(GRUB_ERR_BAD_MODULE,
Bad module is for bad grub modules. It's wrong error code
"Failed to retrieve variable data 0x%" PRIxGRUB_EFI_UINTN_T, status);
> + return;
> + }
> +
> + grub_printf("Attributes:\n");
>
Mark as translatable. Here and later.
> + if (attributes & GRUB_EFI_VARIABLE_NON_VOLATILE)
> + grub_printf("\tNon-Volatile\n");
> + if (attributes & GRUB_EFI_VARIABLE_BOOTSERVICE_ACCESS)
> + grub_printf("\tBoot Service Access\n");
> + if (attributes & GRUB_EFI_VARIABLE_RUNTIME_ACCESS)
> + grub_printf("\tRuntime Service Access\n");
> +
> + if (is_likely_utf16_string(data, data_size))
> + {
> + grub_printf("Value (as UTF-16 string):\n");
> + for (grub_size_t i = 0; i + 1 < data_size; i += 2)
> + {
> + grub_uint16_t ch = data[i] | (data[i+1] << 8);
> + if (ch == 0) break;
> + grub_printf("%c", (char)ch); // crude but works if high
> byte is zero
>
We have a correct UTF-16 to UTF-8 converter.
> + }
> + grub_printf("\n");
> + }
> + else
> + {
> + grub_printf("Value (hex):\n");
> + for (grub_size_t i = 0; i < data_size; i++)
> + {
> + grub_printf("%02x ", data[i]);
>
We have a good hexdump function.
> + if ((i + 1) % 16 == 0)
> + grub_printf("\n");
> + }
> + grub_printf("\n");
> + }
> +
> + grub_free(data);
> +}
> +
> +static grub_err_t
> +dump_efi_variables(void)
> +{
> + grub_efi_status_t status;
> + grub_efi_runtime_services_t *r;
> + grub_efi_uintn_t variable_name_size = 512;
> + grub_efi_char16_t *variable_name;
> + grub_uint8_t *variable_name_string = NULL;
> + grub_guid_t vendor_guid;
> +
> + r = grub_efi_system_table->runtime_services;
> +
> + variable_name = grub_malloc(variable_name_size);
> + if (!variable_name)
> + return grub_error(GRUB_ERR_OUT_OF_MEMORY, "initial malloc
> failed");
>
Just return grub_errno.
> + *variable_name = 0; /* Start with empty string */
> +
> + while (1)
> + {
> + status = r->get_next_variable_name(&variable_name_size,
> variable_name, &vendor_guid);
> + if (status == GRUB_EFI_NOT_FOUND)
> + break;
> + variable_name_string = grub_realloc(variable_name_string,
> variable_name_size);
>
Missing error handling.
> + grub_utf16_to_utf8(variable_name_string, variable_name,
> variable_name_size);
> +
> grub_printf("%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x-%s\n",
> vendor_guid.data1,
>
We have %pG qualifier.
> +
> vendor_guid.data2,
> +
> vendor_guid.data3,
> +
> vendor_guid.data4[0], vendor_guid.data4[1],
> +
> vendor_guid.data4[2], vendor_guid.data4[3],
> +
> vendor_guid.data4[4], vendor_guid.data4[5],
> +
> vendor_guid.data4[6], vendor_guid.data4[7],
> +
> variable_name_string);
> + get_variable_data((char*)variable_name_string,
> &vendor_guid);
> + }
> +
> + grub_free(variable_name);
> + grub_free(variable_name_string);
> + return GRUB_ERR_NONE;
> +}
> +
> +static grub_err_t
> +grub_cmd_efivar (grub_command_t cmd __attribute__((unused)),
> + int argc __attribute__((unused)), char **argv
> __attribute__((unused)))
> +{
> + return dump_efi_variables();
> +}
> +
> +static grub_command_t cmd;
> +
> +GRUB_MOD_INIT(efivar)
> +{
> + cmd = grub_register_command("efivar", grub_cmd_efivar, NULL,
> N_("Display UEFI variables."));
>
I'd rather have function lsefivar [-l] to be consistent with other similar
GRUB commands. Without -l it would skip variable contents
> +}
> +GRUB_MOD_FINI(efivar)
> +{
> + grub_unregister_command(cmd);
> +}
> --
> 2.49.0
>
>
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