--- /dev/null
+/*
+ * EFI utils
+ *
+ * Copyright (c) 2017 Rob Clark
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <malloc.h>
+#include <charset.h>
+#include <efi_loader.h>
+
+#define READ_ONLY BIT(31)
+
+/*
+ * Mapping between EFI variables and u-boot variables:
+ *
+ * efi_$guid_$varname = {attributes}(type)value
+ *
+ * For example:
+ *
+ * efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_OsIndicationsSupported=
+ * "{ro,boot,run}(blob)0000000000000000"
+ * efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_BootOrder=
+ * "(blob)00010000"
+ *
+ * The attributes are a comma separated list of these possible
+ * attributes:
+ *
+ * + ro - read-only
+ * + boot - boot-services access
+ * + run - runtime access
+ *
+ * NOTE: with current implementation, no variables are available after
+ * ExitBootServices, and all are persisted (if possible).
+ *
+ * If not specified, the attributes default to "{boot}".
+ *
+ * The required type is one of:
+ *
+ * + utf8 - raw utf8 string
+ * + blob - arbitrary length hex string
+ *
+ * Maybe a utf16 type would be useful to for a string value to be auto
+ * converted to utf16?
+ */
+
+#define MAX_VAR_NAME 31
+#define MAX_NATIVE_VAR_NAME \
+ (strlen("efi_xxxxxxxx-xxxx-xxxx-xxxxxxxxxxxxxxxx_") + \
+ (MAX_VAR_NAME * MAX_UTF8_PER_UTF16))
+
+static int hex(unsigned char ch)
+{
+ if (ch >= 'a' && ch <= 'f')
+ return ch-'a'+10;
+ if (ch >= '0' && ch <= '9')
+ return ch-'0';
+ if (ch >= 'A' && ch <= 'F')
+ return ch-'A'+10;
+ return -1;
+}
+
+static const char *hex2mem(u8 *mem, const char *hexstr, int count)
+{
+ memset(mem, 0, count/2);
+
+ do {
+ int nibble;
+
+ *mem = 0;
+
+ if (!count || !*hexstr)
+ break;
+
+ nibble = hex(*hexstr);
+ if (nibble < 0)
+ break;
+
+ *mem = nibble;
+ count--;
+ hexstr++;
+
+ if (!count || !*hexstr)
+ break;
+
+ nibble = hex(*hexstr);
+ if (nibble < 0)
+ break;
+
+ *mem = (*mem << 4) | nibble;
+ count--;
+ hexstr++;
+ mem++;
+
+ } while (1);
+
+ if (*hexstr)
+ return hexstr;
+
+ return NULL;
+}
+
+static char *mem2hex(char *hexstr, const u8 *mem, int count)
+{
+ static const char hexchars[] = "0123456789abcdef";
+
+ while (count-- > 0) {
+ u8 ch = *mem++;
+ *hexstr++ = hexchars[ch >> 4];
+ *hexstr++ = hexchars[ch & 0xf];
+ }
+
+ return hexstr;
+}
+
+static efi_status_t efi_to_native(char *native, s16 *variable_name,
+ efi_guid_t *vendor)
+{
+ size_t len;
+
+ len = utf16_strlen((u16 *)variable_name);
+ if (len >= MAX_VAR_NAME)
+ return EFI_DEVICE_ERROR;
+
+ native += sprintf(native, "efi_%pUl_", vendor);
+ native = (char *)utf16_to_utf8((u8 *)native, (u16 *)variable_name, len);
+ *native = '\0';
+
+ return EFI_SUCCESS;
+}
+
+static const char *prefix(const char *str, const char *prefix)
+{
+ size_t n = strlen(prefix);
+ if (!strncmp(prefix, str, n))
+ return str + n;
+ return NULL;
+}
+
+/* parse attributes part of variable value, if present: */
+static const char *parse_attr(const char *str, u32 *attrp)
+{
+ u32 attr = 0;
+ char sep = '{';
+
+ if (*str != '{') {
+ *attrp = EFI_VARIABLE_BOOTSERVICE_ACCESS;
+ return str;
+ }
+
+ while (*str == sep) {
+ const char *s;
+
+ str++;
+
+ if ((s = prefix(str, "ro"))) {
+ attr |= READ_ONLY;
+ } else if ((s = prefix(str, "boot"))) {
+ attr |= EFI_VARIABLE_BOOTSERVICE_ACCESS;
+ } else if ((s = prefix(str, "run"))) {
+ attr |= EFI_VARIABLE_RUNTIME_ACCESS;
+ } else {
+ printf("invalid attribute: %s\n", str);
+ break;
+ }
+
+ str = s;
+ sep = ',';
+ }
+
+ str++;
+
+ *attrp = attr;
+
+ return str;
+}
+
+/* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#GetVariable.28.29 */
+efi_status_t EFIAPI efi_get_variable(s16 *variable_name,
+ efi_guid_t *vendor, u32 *attributes,
+ unsigned long *data_size, void *data)
+{
+ char native_name[MAX_NATIVE_VAR_NAME + 1];
+ efi_status_t ret;
+ unsigned long in_size;
+ const char *val, *s;
+ u32 attr;
+
+ EFI_ENTRY("%p %p %p %p %p", variable_name, vendor, attributes,
+ data_size, data);
+
+ if (!variable_name || !vendor || !data_size)
+ return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+ ret = efi_to_native(native_name, variable_name, vendor);
+ if (ret)
+ return EFI_EXIT(ret);
+
+ debug("%s: get '%s'\n", __func__, native_name);
+
+ val = env_get(native_name);
+ if (!val)
+ return EFI_EXIT(EFI_NOT_FOUND);
+
+ val = parse_attr(val, &attr);
+
+ in_size = *data_size;
+
+ if ((s = prefix(val, "(blob)"))) {
+ unsigned len = strlen(s);
+
+ /* two characters per byte: */
+ len = DIV_ROUND_UP(len, 2);
+ *data_size = len;
+
+ if (in_size < len)
+ return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
+
+ if (!data)
+ return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+ if (hex2mem(data, s, len * 2))
+ return EFI_EXIT(EFI_DEVICE_ERROR);
+
+ debug("%s: got value: \"%s\"\n", __func__, s);
+ } else if ((s = prefix(val, "(utf8)"))) {
+ unsigned len = strlen(s) + 1;
+
+ *data_size = len;
+
+ if (in_size < len)
+ return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
+
+ if (!data)
+ return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+ memcpy(data, s, len);
+ ((char *)data)[len] = '\0';
+
+ debug("%s: got value: \"%s\"\n", __func__, (char *)data);
+ } else {
+ debug("%s: invalid value: '%s'\n", __func__, val);
+ return EFI_EXIT(EFI_DEVICE_ERROR);
+ }
+
+ if (attributes)
+ *attributes = attr & EFI_VARIABLE_MASK;
+
+ return EFI_EXIT(EFI_SUCCESS);
+}
+
+/* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#GetNextVariableName.28.29 */
+efi_status_t EFIAPI efi_get_next_variable(
+ unsigned long *variable_name_size,
+ s16 *variable_name, efi_guid_t *vendor)
+{
+ EFI_ENTRY("%p %p %p", variable_name_size, variable_name, vendor);
+
+ return EFI_EXIT(EFI_DEVICE_ERROR);
+}
+
+/* http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#SetVariable.28.29 */
+efi_status_t EFIAPI efi_set_variable(s16 *variable_name,
+ efi_guid_t *vendor, u32 attributes,
+ unsigned long data_size, void *data)
+{
+ char native_name[MAX_NATIVE_VAR_NAME + 1];
+ efi_status_t ret = EFI_SUCCESS;
+ char *val, *s;
+ u32 attr;
+
+ EFI_ENTRY("%p %p %x %lu %p", variable_name, vendor, attributes,
+ data_size, data);
+
+ if (!variable_name || !vendor)
+ return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+ ret = efi_to_native(native_name, variable_name, vendor);
+ if (ret)
+ return EFI_EXIT(ret);
+
+#define ACCESS_ATTR (EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS)
+
+ if ((data_size == 0) || !(attributes & ACCESS_ATTR)) {
+ /* delete the variable: */
+ env_set(native_name, NULL);
+ return EFI_EXIT(EFI_SUCCESS);
+ }
+
+ val = env_get(native_name);
+ if (val) {
+ parse_attr(val, &attr);
+
+ if (attr & READ_ONLY)
+ return EFI_EXIT(EFI_WRITE_PROTECTED);
+ }
+
+ val = malloc(2 * data_size + strlen("{ro,run,boot}(blob)") + 1);
+ if (!val)
+ return EFI_EXIT(EFI_OUT_OF_RESOURCES);
+
+ s = val;
+
+ /* store attributes: */
+ attributes &= (EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS);
+ s += sprintf(s, "{");
+ while (attributes) {
+ u32 attr = 1 << (ffs(attributes) - 1);
+
+ if (attr == EFI_VARIABLE_BOOTSERVICE_ACCESS)
+ s += sprintf(s, "boot");
+ else if (attr == EFI_VARIABLE_RUNTIME_ACCESS)
+ s += sprintf(s, "run");
+
+ attributes &= ~attr;
+ if (attributes)
+ s += sprintf(s, ",");
+ }
+ s += sprintf(s, "}");
+
+ /* store payload: */
+ s += sprintf(s, "(blob)");
+ s = mem2hex(s, data, data_size);
+ *s = '\0';
+
+ debug("%s: setting: %s=%s\n", __func__, native_name, val);
+
+ if (env_set(native_name, val))
+ ret = EFI_DEVICE_ERROR;
+
+ free(val);
+
+ return EFI_EXIT(ret);
+}
projects / oweals / u-boot.git / commitdiff