Add efi getenv command
Add a command to obtain the contents of EFI firmware variables.
This commit is contained in:
Matthew Garrett
parent
9b669efb38
commit
2755ecd157
2 changed files with 160 additions and 0 deletions
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@ -821,6 +821,13 @@ module = {
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enable = x86_64_efi;
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};
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module = {
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name = getenv;
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common = commands/efi/getenv.c;
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enable = i386_efi;
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enable = x86_64_efi;
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};
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module = {
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name = gptsync;
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common = commands/gptsync.c;
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153
grub-core/commands/efi/getenv.c
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153
grub-core/commands/efi/getenv.c
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@ -0,0 +1,153 @@
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/* getenv.c - retrieve EFI variables. */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2009 Free Software Foundation, Inc.
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* Copyright (C) 2014 CoreOS, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/efi/efi.h>
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#include <grub/dl.h>
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#include <grub/env.h>
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#include <grub/err.h>
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#include <grub/extcmd.h>
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#include <grub/i18n.h>
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#include <grub/misc.h>
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#include <grub/mm.h>
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GRUB_MOD_LICENSE ("GPLv3+");
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static const struct grub_arg_option options_getenv[] = {
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{"var-name", 'e', 0,
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N_("Environment variable to query"),
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N_("VARNAME"), ARG_TYPE_STRING},
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{"var-guid", 'g', 0,
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N_("GUID of environment variable to query"),
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N_("GUID"), ARG_TYPE_STRING},
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{"binary", 'b', 0,
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N_("Read binary data and represent it as hex"),
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0, ARG_TYPE_NONE},
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{0, 0, 0, 0, 0, 0}
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};
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enum options_getenv
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{
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GETENV_VAR_NAME,
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GETENV_VAR_GUID,
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GETENV_BINARY,
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};
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static grub_err_t
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grub_cmd_getenv (grub_extcmd_context_t ctxt, int argc, char **args)
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{
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struct grub_arg_list *state = ctxt->state;
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char *envvar = NULL, *guid = NULL, *bindata = NULL, *data = NULL;
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grub_size_t datasize;
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grub_efi_guid_t efi_var_guid;
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grub_efi_boolean_t binary = state[GETENV_BINARY].set;
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unsigned int i;
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if (!state[GETENV_VAR_NAME].set || !state[GETENV_VAR_GUID].set)
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{
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grub_error (GRUB_ERR_INVALID_COMMAND, N_("-e and -g are required"));
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goto done;
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}
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if (argc != 1)
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{
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grub_error (GRUB_ERR_BAD_ARGUMENT, N_("unexpected arguments"));
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goto done;
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}
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envvar = state[GETENV_VAR_NAME].arg;
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guid = state[GETENV_VAR_GUID].arg;
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if (grub_strlen(guid) != 36 ||
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guid[8] != '-' ||
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guid[13] != '-' ||
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guid[18] != '-' ||
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guid[23] != '-')
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{
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grub_error (GRUB_ERR_BAD_ARGUMENT, N_("invalid GUID"));
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goto done;
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}
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/* Forgive me father for I have sinned */
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guid[8] = 0;
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efi_var_guid.data1 = grub_strtoul(guid, NULL, 16);
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guid[13] = 0;
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efi_var_guid.data2 = grub_strtoul(guid + 9, NULL, 16);
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guid[18] = 0;
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efi_var_guid.data3 = grub_strtoul(guid + 14, NULL, 16);
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efi_var_guid.data4[7] = grub_strtoul(guid + 34, NULL, 16);
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guid[34] = 0;
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efi_var_guid.data4[6] = grub_strtoul(guid + 32, NULL, 16);
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guid[32] = 0;
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efi_var_guid.data4[5] = grub_strtoul(guid + 30, NULL, 16);
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guid[30] = 0;
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efi_var_guid.data4[4] = grub_strtoul(guid + 28, NULL, 16);
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guid[28] = 0;
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efi_var_guid.data4[3] = grub_strtoul(guid + 26, NULL, 16);
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guid[26] = 0;
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efi_var_guid.data4[2] = grub_strtoul(guid + 24, NULL, 16);
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guid[23] = 0;
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efi_var_guid.data4[1] = grub_strtoul(guid + 21, NULL, 16);
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guid[21] = 0;
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efi_var_guid.data4[0] = grub_strtoul(guid + 19, NULL, 16);
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data = grub_efi_get_variable(envvar, &efi_var_guid, &datasize);
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if (!data || !datasize)
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{
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grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("No such variable"));
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goto done;
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}
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if (binary)
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{
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bindata = grub_zalloc(datasize * 2 + 1);
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for (i=0; i<datasize; i++)
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grub_snprintf(bindata + i*2, 3, "%02x", data[i]);
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if (grub_env_set (args[0], bindata))
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goto done;
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}
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else if (grub_env_set (args[0], data))
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{
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goto done;
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}
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grub_errno = GRUB_ERR_NONE;
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done:
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grub_free(bindata);
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grub_free(data);
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return grub_errno;
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}
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static grub_extcmd_t cmd_getenv;
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GRUB_MOD_INIT(getenv)
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{
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cmd_getenv = grub_register_extcmd ("getenv", grub_cmd_getenv, 0,
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N_("-e envvar -g guidenv setvar"),
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N_("Read a firmware environment variable"),
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options_getenv);
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}
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GRUB_MOD_FINI(getenv)
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{
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grub_unregister_extcmd (cmd_getenv);
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}
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