Please, see updated patch below. I tried to reuse GRUB hexdump function, so as a result dump will not work with setting vatiables - just dumping to stdout. But it doesn't make sense to assign dump to a variable anyway.
diff --git a/grub-core/commands/efi/efivar.c b/grub-core/commands/efi/efivar.c new file mode 100644 index 0000000..3ffd5ca --- /dev/null +++ b/grub-core/commands/efi/efivar.c @@ -0,0 +1,253 @@ +/* efivar.c - Read EFI global variables. */ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2015 Free Software Foundation, Inc. + * Copyright (C) 2015 CloudFlare, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/types.h> +#include <grub/mm.h> +#include <grub/misc.h> +#include <grub/efi/api.h> +#include <grub/efi/efi.h> +#include <grub/extcmd.h> +#include <grub/env.h> +#include <grub/lib/hexdump.h> + +GRUB_MOD_LICENSE ("GPLv3+"); + +static const struct grub_arg_option options[] = { + {"format", 'f', GRUB_ARG_OPTION_OPTIONAL, N_("Parse EFI_VAR in specific format (hex, uint8, ascii, raw, dump). Default: hex."), N_("FORMAT"), ARG_TYPE_STRING}, + {"set", 's', GRUB_ARG_OPTION_OPTIONAL, N_("Save parsed result to environment variable (does not work with dump)."), N_("ENV_VAR"), ARG_TYPE_STRING}, + {0, 0, 0, 0, 0, 0} +}; + +enum efi_var_type + { + EFI_VAR_ASCII = 0, + EFI_VAR_RAW, + EFI_VAR_UINT8, + EFI_VAR_HEX, + EFI_VAR_DUMP, + EFI_VAR_INVALID = -1 + }; + +static enum efi_var_type +parse_efi_var_type (const char *type) +{ + if (!grub_strncmp (type, "ascii", sizeof("ascii"))) + return EFI_VAR_ASCII; + + if (!grub_strncmp (type, "raw", sizeof("raw"))) + return EFI_VAR_ASCII; + + if (!grub_strncmp (type, "uint8", sizeof("uint8"))) + return EFI_VAR_UINT8; + + if (!grub_strncmp (type, "hex", sizeof("hex"))) + return EFI_VAR_HEX; + + if (!grub_strncmp (type, "dump", sizeof("dump"))) + return EFI_VAR_DUMP; + + return EFI_VAR_INVALID; +} + +static int +grub_print_ascii (char *str, char c) +{ + if (grub_iscntrl (c)) + { + switch (c) + { + case '\0': + str[0] = '\\'; + str[1] = '0'; + return 2; + + case '\a': + str[0] = '\\'; + str[1] = 'a'; + return 2; + + case '\b': + str[0] = '\\'; + str[1] = 'b'; + return 2; + + case '\f': + str[0] = '\\'; + str[1] = 'f'; + return 2; + + case '\n': + str[0] = '\\'; + str[1] = 'n'; + return 2; + + case '\r': + str[0] = '\\'; + str[1] = 'r'; + return 2; + + case '\t': + str[0] = '\\'; + str[1] = 't'; + return 2; + + case '\v': + str[0] = '\\'; + str[1] = 'v'; + return 2; + + default: + str[0] = '.'; /* as in hexdump -C */ + return 1; + } + } + + str[0] = c; + return 1; +} + +static grub_err_t +grub_cmd_get_efi_var (struct grub_extcmd_context *ctxt, + int argc, char **args) +{ + struct grub_arg_list *state = ctxt->state; + grub_err_t status; + void *efi_var = NULL; + grub_size_t efi_var_size = 0; + enum efi_var_type efi_type = EFI_VAR_HEX; + grub_efi_guid_t global = GRUB_EFI_GLOBAL_VARIABLE_GUID; + char *env_var = NULL; + grub_size_t i; + char *ptr; + + if (1 != argc) + return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("two arguments expected")); + + if (state[0].set) + efi_type = parse_efi_var_type (state[0].arg); + + if (EFI_VAR_INVALID == efi_type) + return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("invalid format specifier")); + + efi_var = grub_efi_get_variable (args[0], &global, &efi_var_size); + if (!efi_var || !efi_var_size) + { + status = grub_error (GRUB_ERR_READ_ERROR, N_("cannot read variable")); + goto err; + } + + switch (efi_type) + { + case EFI_VAR_ASCII: + env_var = grub_malloc (efi_var_size * 2 + 1); + if (!env_var) + { + status = grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory")); + break; + } + + ptr = env_var; + + for (i = 0; i < efi_var_size; i++) + ptr += grub_print_ascii (ptr, ((const char *)efi_var)[i]); + *ptr = '\0'; + break; + + case EFI_VAR_RAW: + env_var = grub_malloc (efi_var_size + 1); + if (!env_var) + { + status = grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory")); + break; + } + grub_memcpy (env_var, efi_var, efi_var_size); + env_var[efi_var_size] = '\0'; + break; + + case EFI_VAR_UINT8: + env_var = grub_malloc (4); + if (!env_var) + { + status = grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory")); + break; + } + grub_snprintf (env_var, 4, "%u", *((grub_uint8_t *)efi_var)); + break; + + case EFI_VAR_HEX: + env_var = grub_malloc (efi_var_size * 2 + 1); + if (!env_var) + { + status = grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory")); + break; + } + for (i = 0; i < efi_var_size; i++) + grub_snprintf (env_var + (i * 2), 3, "%02x", ((grub_uint8_t *)efi_var)[i]); + break; + + case EFI_VAR_DUMP: + if (state[1].set) + status = grub_error (GRUB_ERR_BAD_ARGUMENT, N_("cannot set variable with dump format specifier")); + else + { + hexdump (0, (char *)efi_var, efi_var_size); + status = GRUB_ERR_NONE; + } + break; + + default: + status = grub_error (GRUB_ERR_BUG, N_("should not happen (bug in module?)")); + } + + if (efi_type != EFI_VAR_DUMP) + { + if (state[1].set) + status = grub_env_set (state[1].arg, env_var); + else + { + grub_printf ("%s\n", (const char *)env_var); + status = GRUB_ERR_NONE; + } + } + +err: + + if (env_var) + grub_free (env_var); + + if (efi_var) + grub_free (efi_var); + + return status; +} + +static grub_extcmd_t cmd = NULL; + +GRUB_MOD_INIT (efivar) +{ + cmd = grub_register_extcmd ("get_efivar", grub_cmd_get_efi_var, 0, N_("[-f FORMAT] [-s ENV_VAR] EFI_VAR"), + N_("Read EFI variable and print it or save its contents to environment variable."), options); +} + +GRUB_MOD_FINI (efivar) +{ + if (cmd) + grub_unregister_extcmd (cmd); +} diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def index a6101de..2c8f023 100644 --- a/grub-core/Makefile.core.def +++ b/grub-core/Makefile.core.def @@ -728,6 +728,12 @@ }; module = { + name = efivar; + efi = commands/efi/efivar.c; + enable = efi; +}; + +module = { name = blocklist; common = commands/blocklist.c; }; On Sat, Nov 14, 2015 at 4:03 AM, Andrei Borzenkov <arvidj...@gmail.com> wrote: > 13.11.2015 22:42, Ignat Korchagin пишет: >>>>> >>>>> +static enum efi_var_type >>>>> +parse_efi_var_type (const char *type) >>>>> +{ >>>>> + if (!grub_strncmp (type, "string", sizeof("string"))) >>>>> + return EFI_VAR_STRING; >>>>> + >>>> >>>> >>>> >>>> I think this should be "ascii" or "utf8". "string" is too ambiguous in >>>> UEFI >>>> environment, it can also mean sequence of UCS-2 characters. >>> >>> I'm still not sure how exactly GRUB + UEFI interprets "raw buffers" >>> when printing. Maybe, to avoid confusion, it might be better to >>> completely remove this option. Basically, you do not want to interpret >>> raw buffers as strings. For best compatibility "hex" mode should be >>> promoted, I guess. What do you think? >> >> Checked again the UEFI spec. For globally defined variables which are >> strings they specify ASCII. So if we leave this option, ascii is the >> best name. >> > > What about > > - ascii - print ASCII characters verbatim, escape non-ASCII in usual way > (similar to "od -c") > > - raw - simply put raw variable without any interpretation. > > This is better aligned with argument describing output formatting rather > than attempting to "type" variable. > > Alternative (or in addition to) ascii - dump which prints usual pretty hex > dump of content (hexdump -C). This is handy to interactively look at > variable content. > > Or, and change name from --type to --format :) > > > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > https://lists.gnu.org/mailman/listinfo/grub-devel _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
