lib/efi: Add new routines to access efi variables

Provide methods to load/store petitboot's configuration on efi-based
platforms. A test case is also provided.

Signed-off-by: Ge Song <ge.song@hxt-semitech.com>
[Cleanup file comments, make efivarfs_path static.]
Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>

1 files changed, 127 insertions, 0 deletions

diff --git a/test/lib/test-efivar.c b/test/lib/test-efivar.c
new file mode 100644
index 0000000..8ceb8f5
--- /dev/null
+++ b/test/lib/test-efivar.c
@@ -0,0 +1,127 @@
+/*
+ *  This program 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; version 2 of the License.
+ *
+ *  This program 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 this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Copyright (C) 2018 Huaxintong Semiconductor Technology Co.,Ltd. All rights
+ *  reserved.
+ *  Author: Ge Song <ge.song@hxt-semitech.com>
+ */
+#include <assert.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <unistd.h>
+
+#include "efi/efivar.h"
+#include "talloc/talloc.h"
+
+#define DEF_ATTR	(EFI_VARIABLE_NON_VOLATILE | \
+	EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS)
+
+static const char *test_efivar_guid = "c9c07add-256e-4452-b911-f8d0d35a1ac7";
+static const char *test_varname = "efivartest";
+static const char *test_data = "petitboot";
+
+static char* find_efitest_path(void)
+{
+	static char dir[PATH_MAX] = {0};
+	static bool run = false;
+	char *rest_path = "/efivarfs_data/";
+	char *pos = NULL;
+
+	if (run)
+		return dir;
+
+	readlink("/proc/self/exe", dir, PATH_MAX);
+
+	pos = strrchr(dir, '/');
+	*pos = '\0';
+
+	strcat(dir, rest_path);
+	run = true;
+
+	return dir;
+}
+
+static bool probe(void)
+{
+	char *path;
+	int rc;
+
+	path = find_efitest_path();
+
+	rc = access(path, F_OK);
+	if (rc) {
+		if (errno == ENOENT) {
+			rc = mkdir(path, 0755);
+			if(rc)
+				return false;
+		} else {
+			return false;
+		}
+	}
+
+	set_efivarfs_path(path);
+
+	return true;
+}
+
+int main(void)
+{
+	void *ctx = NULL;
+	int rc, errno_value;
+	size_t size;
+	uint8_t *data = NULL;
+	uint32_t attr = DEF_ATTR;
+	char *path = NULL;
+
+	if(!probe())
+		return ENOENT;
+
+	talloc_new(ctx);
+	size = strlen(test_data) + 1;
+	rc = efi_set_variable(ctx, test_efivar_guid, test_varname,
+				(uint8_t *)test_data, size, attr);
+
+	rc = efi_get_variable(ctx, test_efivar_guid, test_varname,
+				&data, &size, &attr);
+
+	assert(data != NULL);
+	rc = strcmp((char *)data, test_data);
+	if (rc) {
+		talloc_free(ctx);
+		assert(0);
+	}
+
+	rc = efi_del_variable(ctx, test_efivar_guid, test_varname);
+
+	rc = efi_get_variable(ctx, test_efivar_guid, test_varname,
+				&data, &size, &attr);
+
+	errno_value = errno;
+	talloc_free(ctx);
+
+	assert(errno_value == ENOENT);
+
+	path = find_efitest_path();
+	rmdir(path);
+
+	return EXIT_SUCCESS;
+}