[U-Boot] [PATCH] efi_loader: variable: support APPEND_WRITE

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

If EFI_VARIABLE_APPEND_WRITE is specified in attributes at
efi_set_variable(), specified data will be appended to the variable's
original value. Attributes other than APPEND_WRITE should not be
modified.

With this patch, APPEND_WRITE test in 'variables' selftest will pass.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
 lib/efi_loader/efi_variable.c | 50 +++++++++++++++++++++--------------
 1 file changed, 30 insertions(+), 20 deletions(-)

diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 6687b69a400d..5d1ee50a606e 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -423,18 +423,17 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
 				     const efi_guid_t *vendor, u32 attributes,
 				     efi_uintn_t data_size, const void *data)
 {
-	char *native_name = NULL, *val = NULL, *s;
+	char *native_name = NULL, *oval, *val = NULL, *s;
+	size_t oval_size;
 	efi_status_t ret = EFI_SUCCESS;
 	u32 attr;
 
 	EFI_ENTRY("\"%ls\" %pUl %x %zu %p", variable_name, vendor, attributes,
 		  data_size, data);
 
-	/* TODO: implement APPEND_WRITE */
 	if (!variable_name || !*variable_name || !vendor ||
 	    ((attributes & EFI_VARIABLE_RUNTIME_ACCESS) &&
-	     !(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)) ||
-	    (attributes & EFI_VARIABLE_APPEND_WRITE)) {
+	     !(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS))) {
 		ret = EFI_INVALID_PARAMETER;
 		goto out;
 	}
@@ -452,28 +451,37 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
 		goto out;
 	}
 
-	val = env_get(native_name);
-	if (val) {
-		parse_attr(val, &attr);
+	oval = env_get(native_name);
+	if (oval) {
+		oval = parse_attr(oval, &attr);
 
-		/* We should not free val */
-		val = NULL;
 		if (attr & READ_ONLY) {
 			ret = EFI_WRITE_PROTECTED;
 			goto out;
 		}
 
-		/*
-		 * attributes won't be changed
-		 * TODO: take care of APPEND_WRITE once supported
-		 */
-		if (attr != attributes) {
+		/* attributes won't be changed */
+		if (attr != (attributes & ~EFI_VARIABLE_APPEND_WRITE)) {
 			ret = EFI_INVALID_PARAMETER;
 			goto out;
 		}
+
+		if (attributes & EFI_VARIABLE_APPEND_WRITE) {
+			if (!prefix(oval, "(blob)")) {
+				/* TODO: should support utf8? */
+				return EFI_DEVICE_ERROR;
+				goto out;
+			}
+			oval_size = strlen(oval);
+		} else {
+			oval_size = 0;
+		}
+	} else {
+		oval_size = 0;
 	}
 
-	val = malloc(2 * data_size + strlen("{ro,run,boot,nv}(blob)") + 1);
+	val = malloc(oval_size + 2 * data_size
+		     + strlen("{ro,run,boot,nv}(blob)") + 1);
 	if (!val) {
 		ret = EFI_OUT_OF_RESOURCES;
 		goto out;
@@ -481,10 +489,7 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
 
 	s = val;
 
-	/*
-	 * store attributes
-	 * TODO: several attributes are not supported
-	 */
+	/* store attributes */
 	attributes &= (EFI_VARIABLE_NON_VOLATILE |
 		       EFI_VARIABLE_BOOTSERVICE_ACCESS |
 		       EFI_VARIABLE_RUNTIME_ACCESS);
@@ -505,8 +510,13 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
 	}
 	s += sprintf(s, "}");
 
+	if (oval_size)
+		/* APPEND_WRITE */
+		s += sprintf(s, oval);
+	else
+		s += sprintf(s, "(blob)");
+
 	/* store payload: */
-	s += sprintf(s, "(blob)");
 	s = bin2hex(s, data, data_size);
 	*s = '\0';
 
-- 
2.21.0