|
| From: | SevenBits |
| Subject: | Re: [PATCH] Add efi getenv command |
| Date: | Tue, 24 Jan 2017 00:41:11 +0000 |
Add a command to obtain the contents of EFI firmware variables.
---
docs/grub.texi | 7 ++
grub-core/Makefile.core.def | 7 ++
grub-core/commands/efi/getenv.c | 153 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 167 insertions(+)
create mode 100644 grub-core/commands/efi/getenv.c
diff --git a/docs/grub.texi b/docs/grub.texi
index b9ddb9b..4469638 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -3818,6 +3818,7 @@ you forget a command, you can run the command @command{help}
* eval:: Evaluate agruments as GRUB commands
* export:: Export an environment variable
* false:: Do nothing, unsuccessfully
+* getenv:: Retrieve an EFI firmware variable
* gettext:: Translate a string
* gptsync:: Fill an MBR based on GPT entries
* halt:: Shut down your computer
@@ -4258,6 +4259,12 @@ Do nothing, unsuccessfully. This is mainly useful in control constructs
such as @code{if} and @code{while} (@pxref{Shell-like scripting}).
address@hidden deffn
address@hidden getenv
address@hidden getenv
+
address@hidden Command getenv address@hidden address@hidden envvar
+Retrieves an EFI variable with the name provided by @option{-e} and the GUID
+provied by @option{-g} and stores it in environment variable @var{envvar}
address@hidden gettext
address@hidden gettext
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 2dfa22a..db77a7f 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -817,6 +817,13 @@ module = {
};
module = {
+ name = getenv;
+ common = commands/efi/getenv.c;
+ enable = i386_efi;
+ enable = x86_64_efi;
+};
+
+module = {
name = gptsync;
common = commands/gptsync.c;
};
diff --git a/grub-core/commands/efi/getenv.c b/grub-core/commands/efi/getenv.c
new file mode 100644
index 0000000..5a829f5
--- /dev/null
+++ b/grub-core/commands/efi/getenv.c
@@ -0,0 +1,153 @@
+/* getenv.c - retrieve EFI variables. */
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2009 Free Software Foundation, Inc.
+ * Copyright (C) 2014 CoreOS, 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/efi/efi.h>
+#include <grub/dl.h>
+#include <grub/env.h>
+#include <grub/err.h>
+#include <grub/extcmd.h>
+#include <grub/i18n.h>
+#include <grub/misc.h>
+#include <grub/mm.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static const struct grub_arg_option options_getenv[] = {
+ {"var-name", 'e', 0,
+ N_("Environment variable to query"),
+ N_("VARNAME"), ARG_TYPE_STRING},
+ {"var-guid", 'g', 0,
+ N_("GUID of environment variable to query"),
+ N_("GUID"), ARG_TYPE_STRING},
+ {"binary", 'b', 0,
+ N_("Read binary data and represent it as hex"),
+ 0, ARG_TYPE_NONE},
+ {0, 0, 0, 0, 0, 0}
+};
+
+enum options_getenv
+{
+ GETENV_VAR_NAME,
+ GETENV_VAR_GUID,
+ GETENV_BINARY,
+};
+
+static grub_err_t
+grub_cmd_getenv (grub_extcmd_context_t ctxt, int argc, char **args)
+{
+ struct grub_arg_list *state = ctxt->state;
+ char *envvar = NULL, *guid = NULL, *bindata = NULL, *data = "" class="gmail_msg">
+ grub_size_t datasize;
+ grub_efi_guid_t efi_var_guid;
+ grub_efi_boolean_t binary = state[GETENV_BINARY].set;
+ unsigned int i;
+
+ if (!state[GETENV_VAR_NAME].set || !state[GETENV_VAR_GUID].set)
+ {
+ grub_error (GRUB_ERR_INVALID_COMMAND, N_("-e and -g are required"));
+ goto done;
+ }
+
+ if (argc != 1)
+ {
+ grub_error (GRUB_ERR_BAD_ARGUMENT, N_("unexpected arguments"));
+ goto done;
+ }
+
+ envvar = state[GETENV_VAR_NAME].arg;
+ guid = state[GETENV_VAR_GUID].arg;
+
+ if (grub_strlen(guid) != 36 ||
+ guid[8] != '-' ||
+ guid[13] != '-' ||
+ guid[18] != '-' ||
+ guid[23] != '-')
+ {
+ grub_error (GRUB_ERR_BAD_ARGUMENT, N_("invalid GUID"));
+ goto done;
+ }
+
+ /* Forgive me father for I have sinned */
+ guid[8] = 0;
+ efi_var_guid.data1 = grub_strtoul(guid, NULL, 16);
+ guid[13] = 0;
+ efi_var_guid.data2 = grub_strtoul(guid + 9, NULL, 16);
+ guid[18] = 0;
+ efi_var_guid.data3 = grub_strtoul(guid + 14, NULL, 16);
+ efi_var_guid.data4[7] = grub_strtoul(guid + 34, NULL, 16);
+ guid[34] = 0;
+ efi_var_guid.data4[6] = grub_strtoul(guid + 32, NULL, 16);
+ guid[32] = 0;
+ efi_var_guid.data4[5] = grub_strtoul(guid + 30, NULL, 16);
+ guid[30] = 0;
+ efi_var_guid.data4[4] = grub_strtoul(guid + 28, NULL, 16);
+ guid[28] = 0;
+ efi_var_guid.data4[3] = grub_strtoul(guid + 26, NULL, 16);
+ guid[26] = 0;
+ efi_var_guid.data4[2] = grub_strtoul(guid + 24, NULL, 16);
+ guid[23] = 0;
+ efi_var_guid.data4[1] = grub_strtoul(guid + 21, NULL, 16);
+ guid[21] = 0;
+ efi_var_guid.data4[0] = grub_strtoul(guid + 19, NULL, 16);
+
+ data = "" &efi_var_guid, &datasize);
+
+ if (!data || !datasize)
+ {
+ grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("No such variable"));
+ goto done;
+ }
+
+ if (binary)
+ {
+ bindata = grub_zalloc(datasize * 2 + 1);
+ for (i=0; i<datasize; i++)
+ grub_snprintf(bindata + i*2, 3, "%02x", data[i]);
+
+ if (grub_env_set (args[0], bindata))
+ goto done;
+ }
+ else if (grub_env_set (args[0], data))
+ {
+ goto done;
+ }
+
+ grub_errno = GRUB_ERR_NONE;
+
+done:
+ grub_free(bindata);
+ grub_free(data);
+ return grub_errno;
+}
+
+static grub_extcmd_t cmd_getenv;
+
+GRUB_MOD_INIT(getenv)
+{
+ cmd_getenv = grub_register_extcmd ("getenv", grub_cmd_getenv, 0,
+ N_("-e envvar -g guidenv setvar"),
+ N_("Read a firmware environment variable"),
+ options_getenv);
+}
+
+GRUB_MOD_FINI(getenv)
+{
+ grub_unregister_extcmd (cmd_getenv);
+}
--
2.9.3
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