From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Peter Jones Date: Wed, 16 Jan 2019 13:21:46 -0500 Subject: [PATCH] Add efi-export-env and efi-load-env commands This adds "efi-export-env VARIABLE" and "efi-load-env", which manipulate the environment block stored in the EFI variable GRUB_ENV-91376aff-cba6-42be-949d-06fde81128e8. Signed-off-by: Peter Jones --- grub-core/Makefile.core.def | 6 ++ grub-core/commands/efi/env.c | 168 +++++++++++++++++++++++++++++++++++++++++++ grub-core/kern/efi/efi.c | 3 + grub-core/kern/efi/init.c | 5 -- grub-core/lib/envblk.c | 43 +++++++++++ util/grub-set-bootflag.c | 1 + include/grub/efi/efi.h | 5 ++ include/grub/lib/envblk.h | 3 + 8 files changed, 229 insertions(+), 5 deletions(-) create mode 100644 grub-core/commands/efi/env.c diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def index 1e1534510..81fc27414 100644 --- a/grub-core/Makefile.core.def +++ b/grub-core/Makefile.core.def @@ -820,6 +820,12 @@ module = { enable = efi; }; +module = { + name = efienv; + common = commands/efi/env.c; + enable = efi; +}; + module = { name = efifwsetup; efi = commands/efi/efifwsetup.c; diff --git a/grub-core/commands/efi/env.c b/grub-core/commands/efi/env.c new file mode 100644 index 000000000..cbd13e03e --- /dev/null +++ b/grub-core/commands/efi/env.c @@ -0,0 +1,168 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2012 Free Software Foundation, 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 . + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +GRUB_MOD_LICENSE ("GPLv3+"); + +static const grub_efi_guid_t grub_env_guid = GRUB_EFI_GRUB_VARIABLE_GUID; + +static grub_err_t +grub_efi_export_env(grub_command_t cmd __attribute__ ((unused)), + int argc, char *argv[]) +{ + const char *value; + char *old_value; + struct grub_envblk envblk_s = { NULL, 0 }; + grub_envblk_t envblk = &envblk_s; + grub_err_t err; + int changed = 1; + grub_efi_status_t status; + + grub_dprintf ("efienv", "argc:%d\n", argc); + for (int i = 0; i < argc; i++) + grub_dprintf ("efienv", "argv[%d]: %s\n", i, argv[i]); + + if (argc != 1) + return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("variable name expected")); + + grub_efi_get_variable ("GRUB_ENV", &grub_env_guid, &envblk_s.size, + (void **) &envblk_s.buf); + if (!envblk_s.buf || envblk_s.size < 1) + { + char *buf = grub_malloc (1025); + if (!buf) + return grub_errno; + + grub_memcpy (buf, GRUB_ENVBLK_SIGNATURE, sizeof (GRUB_ENVBLK_SIGNATURE) - 1); + grub_memset (buf + sizeof (GRUB_ENVBLK_SIGNATURE) - 1, '#', + DEFAULT_ENVBLK_SIZE - sizeof (GRUB_ENVBLK_SIGNATURE) + 1); + buf[1024] = '\0'; + + envblk_s.buf = buf; + envblk_s.size = 1024; + } + else + { + char *buf = grub_realloc (envblk_s.buf, envblk_s.size + 1); + if (!buf) + return grub_errno; + + envblk_s.buf = buf; + envblk_s.buf[envblk_s.size] = '\0'; + } + + err = grub_envblk_get(envblk, argv[0], &old_value); + if (err != GRUB_ERR_NONE) + { + grub_dprintf ("efienv", "grub_envblk_get returned %d\n", err); + return err; + } + + value = grub_env_get(argv[0]); + if ((!value && !old_value) || + (value && old_value && !grub_strcmp(old_value, value))) + changed = 0; + + if (old_value) + grub_free(old_value); + + if (changed == 0) + { + grub_dprintf ("efienv", "No changes necessary\n"); + return 0; + } + + if (value) + { + grub_dprintf ("efienv", "setting \"%s\" to \"%s\"\n", argv[0], value); + grub_envblk_set(envblk, argv[0], value); + } + else + { + grub_dprintf ("efienv", "deleting \"%s\" from envblk\n", argv[0]); + grub_envblk_delete(envblk, argv[0]); + } + + grub_dprintf ("efienv", "envblk is %lu bytes:\n\"%s\"\n", envblk_s.size, envblk_s.buf); + + grub_dprintf ("efienv", "removing GRUB_ENV\n"); + status = grub_efi_set_variable ("GRUB_ENV", &grub_env_guid, NULL, 0); + if (status != GRUB_EFI_SUCCESS) + grub_dprintf ("efienv", "removal returned %ld\n", status); + + grub_dprintf ("efienv", "setting GRUB_ENV\n"); + status = grub_efi_set_variable ("GRUB_ENV", &grub_env_guid, + envblk_s.buf, envblk_s.size); + if (status != GRUB_EFI_SUCCESS) + grub_dprintf ("efienv", "setting GRUB_ENV returned %ld\n", status); + + return 0; +} + +static int +set_var (const char *name, const char *value, + void *whitelist __attribute__((__unused__))) +{ + grub_env_set (name, value); + return 0; +} + +static grub_err_t +grub_efi_load_env(grub_command_t cmd __attribute__ ((unused)), + int argc, char *argv[] __attribute__((__unused__))) +{ + struct grub_envblk envblk_s = { NULL, 0 }; + grub_envblk_t envblk = &envblk_s; + + grub_efi_get_variable ("GRUB_ENV", &grub_env_guid, &envblk_s.size, + (void **) &envblk_s.buf); + if (!envblk_s.buf || envblk_s.size < 1) + return 0; + + if (argc > 0) + return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("unexpected argument")); + + grub_envblk_iterate (envblk, NULL, set_var); + grub_free (envblk_s.buf); +} + +static grub_command_t export_cmd, loadenv_cmd; + +GRUB_MOD_INIT(lsefi) +{ + export_cmd = grub_register_command ("efi-export-env", grub_efi_export_env, + N_("VARIABLE_NAME"), N_("Export environment variable to UEFI.")); + loadenv_cmd = grub_register_command ("efi-load-env", grub_efi_load_env, + NULL, N_("Load the grub environment from UEFI.")); +} + +GRUB_MOD_FINI(lsefi) +{ + grub_unregister_command (export_cmd); + grub_unregister_command (loadenv_cmd); +} diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c index 2a446f503..14bc10eb5 100644 --- a/grub-core/kern/efi/efi.c +++ b/grub-core/kern/efi/efi.c @@ -225,6 +225,9 @@ grub_efi_set_variable(const char *var, const grub_efi_guid_t *guid, if (status == GRUB_EFI_SUCCESS) return GRUB_ERR_NONE; + if (status == GRUB_EFI_NOT_FOUND && datasize == 0) + return GRUB_ERR_NONE; + return grub_error (GRUB_ERR_IO, "could not set EFI variable `%s'", var); } diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c index 2d12e6188..0574d8d62 100644 --- a/grub-core/kern/efi/init.c +++ b/grub-core/kern/efi/init.c @@ -85,11 +85,6 @@ stack_protector_init (void) grub_addr_t grub_modbase; -#define GRUB_EFI_GRUB_VARIABLE_GUID \ - { 0x91376aff, 0xcba6, 0x42be, \ - { 0x94, 0x9d, 0x06, 0xfd, 0xe8, 0x11, 0x28, 0xe8 } \ - } - /* Helper for grub_efi_env_init */ static int set_var (const char *name, const char *value, diff --git a/grub-core/lib/envblk.c b/grub-core/lib/envblk.c index 2e4e78b13..874506da1 100644 --- a/grub-core/lib/envblk.c +++ b/grub-core/lib/envblk.c @@ -223,6 +223,49 @@ grub_envblk_delete (grub_envblk_t envblk, const char *name) } } +struct get_var_state { + const char * const name; + char * value; + int found; +}; + +static int +get_var (const char * const name, const char * const value, void *statep) +{ + struct get_var_state *state = (struct get_var_state *)statep; + + if (!grub_strcmp(state->name, name)) + { + state->found = 1; + state->value = grub_strdup(value); + if (!state->value) + grub_errno = grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory")); + + return 1; + } + + return 0; +} + +grub_err_t +grub_envblk_get (grub_envblk_t envblk, const char * const name, char ** const value) +{ + struct get_var_state state = { + .name = name, + .value = NULL, + .found = 0, + }; + + grub_envblk_iterate(envblk, (void *)&state, get_var); + + *value = state.value; + + if (state.found && !state.value) + return grub_errno; + + return GRUB_ERR_NONE; +} + void grub_envblk_iterate (grub_envblk_t envblk, void *hook_data, diff --git a/util/grub-set-bootflag.c b/util/grub-set-bootflag.c index d506f7e75..a6ccc1138 100644 --- a/util/grub-set-bootflag.c +++ b/util/grub-set-bootflag.c @@ -25,6 +25,7 @@ #include /* For *_DIR_NAME defines */ #include +#include #include /* For GRUB_ENVBLK_DEFCFG define */ #include #include diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h index 2e0691454..8dfc89a33 100644 --- a/include/grub/efi/efi.h +++ b/include/grub/efi/efi.h @@ -24,6 +24,11 @@ #include #include +#define GRUB_EFI_GRUB_VARIABLE_GUID \ + { 0x91376aff, 0xcba6, 0x42be, \ + { 0x94, 0x9d, 0x06, 0xfd, 0xe8, 0x11, 0x28, 0xe8 } \ + } + /* Variables. */ extern grub_efi_system_table_t *EXPORT_VAR(grub_efi_system_table); extern grub_efi_handle_t EXPORT_VAR(grub_efi_image_handle); diff --git a/include/grub/lib/envblk.h b/include/grub/lib/envblk.h index c3e655921..ab969af24 100644 --- a/include/grub/lib/envblk.h +++ b/include/grub/lib/envblk.h @@ -22,6 +22,8 @@ #define GRUB_ENVBLK_SIGNATURE "# GRUB Environment Block\n" #define GRUB_ENVBLK_DEFCFG "grubenv" +#define DEFAULT_ENVBLK_SIZE 1024 + #ifndef ASM_FILE struct grub_envblk @@ -33,6 +35,7 @@ typedef struct grub_envblk *grub_envblk_t; grub_envblk_t grub_envblk_open (char *buf, grub_size_t size); int grub_envblk_set (grub_envblk_t envblk, const char *name, const char *value); +grub_err_t grub_envblk_get (grub_envblk_t envblk, const char * const name, char ** const value); void grub_envblk_delete (grub_envblk_t envblk, const char *name); void grub_envblk_iterate (grub_envblk_t envblk, void *hook_data,