[U-Boot] [PATCH v2 07/11] efi_loader: variable: split UEFI variables from U-Boot environment

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

UEFI volatile variables are managed in efi_var_htab while UEFI non-volatile
variables are in efi_nv_var_htab. At every SetVariable API, env_efi_save()
will also be called to save data cache (hash table) to persistent storage.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 lib/efi_loader/efi_variable.c | 162 ++++++++++++++++++++++++++++++++--
 1 file changed, 155 insertions(+), 7 deletions(-)

diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 2f489ab9db97..f7b1ce2f3350 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -48,6 +48,115 @@
  * converted to utf16?
  */
 
+/*
+ * We will maintain two variable database: one for volatile variables,
+ * the other for non-volatile variables. The former exists only in memory
+ * and will go away at re-boot. The latter is currently backed up by the same
+ * device as U-Boot environment and also works as variables cache.
+ */
+
+enum efi_var_type {
+	EFI_VAR_TYPE_VOLATILE,
+	EFI_VAR_TYPE_NON_VOLATILE,
+};
+
+struct hsearch_data efi_var_htab;
+struct hsearch_data efi_nv_var_htab;
+
+static char *env_efi_get(const char *name, int type)
+{
+	struct hsearch_data *htab;
+	ENTRY e, *ep;
+
+	/* WATCHDOG_RESET(); */
+
+	if (type == EFI_VAR_TYPE_VOLATILE)
+		htab = &efi_var_htab;
+	else
+		htab = &efi_nv_var_htab;
+
+	e.key   = name;
+	e.data  = NULL;
+	hsearch_r(e, FIND, &ep, htab, 0);
+
+	return ep ? ep->data : NULL;
+}
+
+static int env_efi_set(const char *name, const char *value, int type)
+{
+	struct hsearch_data *htab;
+	ENTRY e, *ep;
+	int ret;
+
+	if (type == EFI_VAR_TYPE_VOLATILE)
+		htab = &efi_var_htab;
+	else
+		htab = &efi_nv_var_htab;
+
+	/* delete */
+	if (!value || *value == '\0') {
+		ret = hdelete_r(name, htab, H_PROGRAMMATIC);
+		return !ret;
+	}
+
+	/* set */
+	e.key   = name;
+	e.data  = (char *)value;
+	hsearch_r(e, ENTER, &ep, htab, H_PROGRAMMATIC);
+	if (!ep) {
+		printf("## Error inserting \"%s\" variable, errno=%d\n",
+		       name, errno);
+		return 1;
+	}
+
+	return 0;
+}
+
+int efi_variable_import(const char *buf, int check)
+{
+	env_t *ep = (env_t *)buf;
+
+	if (check) {
+		u32 crc;
+
+		memcpy(&crc, &ep->crc, sizeof(crc));
+
+		if (crc32(0, ep->data, CONFIG_ENV_EFI_SIZE) != crc) {
+			pr_err("bad CRC of UEFI variables\n");
+			return -ENOMSG; /* needed for env_load() */
+		}
+	}
+
+	if (himport_r(&efi_nv_var_htab, (char *)ep->data, CONFIG_ENV_EFI_SIZE,
+		      '\0', 0, 0, 0, NULL))
+		return 0;
+
+	pr_err("Cannot import environment: errno = %d\n", errno);
+
+	/* set_default_env("import failed", 0); */
+
+	return -EIO;
+}
+
+/* Export the environment and generate CRC for it. */
+int efi_variable_export(env_t *env_out)
+{
+	char *res;
+	ssize_t	len;
+
+	res = (char *)env_out->data;
+	len = hexport_r(&efi_nv_var_htab, '\0', 0, &res, CONFIG_ENV_EFI_SIZE,
+			0, NULL);
+	if (len < 0) {
+		pr_err("Cannot export environment: errno = %d\n", errno);
+		return 1;
+	}
+
+	env_out->crc = crc32(0, env_out->data, CONFIG_ENV_EFI_SIZE);
+
+	return 0;
+}
+
 #define PREFIX_LEN (strlen("efi_xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx_"))
 
 /**
@@ -184,7 +293,9 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
 
 	EFI_PRINT("get '%s'\n", native_name);
 
-	val = env_get(native_name);
+	val = env_efi_get(native_name, EFI_VAR_TYPE_VOLATILE);
+	if (!val)
+		val = env_efi_get(native_name, EFI_VAR_TYPE_NON_VOLATILE);
 	free(native_name);
 	if (!val)
 		return EFI_EXIT(EFI_NOT_FOUND);
@@ -326,7 +437,7 @@ efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
 					       u16 *variable_name,
 					       const efi_guid_t *vendor)
 {
-	char *native_name, *variable;
+	char *native_name, *variable, *tmp_list, *merged_list;
 	ssize_t name_len, list_len;
 	char regex[256];
 	char * const regexlist[] = {regex};
@@ -382,10 +493,39 @@ efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
 		efi_cur_variable = NULL;
 
 		snprintf(regex, 256, "efi_.*-.*-.*-.*-.*_.*");
-		list_len = hexport_r(&env_htab, '\n',
+		list_len = hexport_r(&efi_var_htab, '\n',
 				     H_MATCH_REGEX | H_MATCH_KEY,
 				     &efi_variables_list, 0, 1, regexlist);
-		/* 1 indicates that no match was found */
+		/*
+		 * Note: '1' indicates that nothing is matched
+		 */
+		if (list_len <= 1) {
+			free(efi_variables_list);
+			efi_variables_list = NULL;
+			list_len = hexport_r(&efi_nv_var_htab, '\n',
+					     H_MATCH_REGEX | H_MATCH_KEY,
+					     &efi_variables_list, 0, 1,
+					     regexlist);
+		} else {
+			tmp_list = NULL;
+			list_len = hexport_r(&efi_nv_var_htab, '\n',
+					     H_MATCH_REGEX | H_MATCH_KEY,
+					     &tmp_list, 0, 1,
+					     regexlist);
+			if (list_len <= 1) {
+				list_len = 2; /* don't care actual number */
+			} else {
+				/* merge two variables lists */
+				merged_list = malloc(strlen(efi_variables_list)
+							+ strlen(tmp_list) + 1);
+				strcpy(merged_list, efi_variables_list);
+				strcat(merged_list, tmp_list);
+				free(efi_variables_list);
+				free(tmp_list);
+				efi_variables_list = merged_list;
+			}
+		}
+
 		if (list_len <= 1)
 			return EFI_EXIT(EFI_NOT_FOUND);
 
@@ -420,6 +560,7 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
 	char *native_name = NULL, *val = NULL, *s;
 	efi_status_t ret = EFI_SUCCESS;
 	u32 attr;
+	int type;
 
 	EFI_ENTRY("\"%ls\" %pUl %x %zu %p", variable_name, vendor, attributes,
 		  data_size, data);
@@ -435,14 +576,18 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
 
 #define ACCESS_ATTR (EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS)
 
+	type = (attributes & EFI_VARIABLE_NON_VOLATILE) ?
+		EFI_VAR_TYPE_NON_VOLATILE : EFI_VAR_TYPE_VOLATILE;
 	if ((data_size == 0) || !(attributes & ACCESS_ATTR)) {
 		/* delete the variable: */
-		env_set(native_name, NULL);
+		env_efi_set(native_name, NULL, type);
 		ret = EFI_SUCCESS;
 		goto out;
 	}
 
-	val = env_get(native_name);
+	val = env_efi_get(native_name, EFI_VAR_TYPE_VOLATILE);
+	if (!val)
+		val = env_efi_get(native_name, EFI_VAR_TYPE_NON_VOLATILE);
 	if (val) {
 		parse_attr(val, &attr);
 
@@ -493,9 +638,12 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
 
 	EFI_PRINT("setting: %s=%s\n", native_name, val);
 
-	if (env_set(native_name, val))
+	if (env_efi_set(native_name, val, type))
 		ret = EFI_DEVICE_ERROR;
 
+	/* FIXME: what if save failed? */
+	env_efi_save();
+
 out:
 	free(native_name);
 	free(val);
-- 
2.20.1