efi_loader: variable: support APPEND_WRITE
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>
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 6687b69..48ee255 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -424,17 +424,17 @@
efi_uintn_t data_size, const void *data)
{
char *native_name = NULL, *val = NULL, *s;
+ const char *old_val;
+ size_t old_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;
}
@@ -445,35 +445,51 @@
#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);
- ret = EFI_SUCCESS;
- goto out;
- }
-
- val = env_get(native_name);
- if (val) {
- parse_attr(val, &attr);
+ old_val = env_get(native_name);
+ if (old_val) {
+ old_val = parse_attr(old_val, &attr);
- /* We should not free val */
- val = NULL;
+ /* check read-only first */
if (attr & READ_ONLY) {
ret = EFI_WRITE_PROTECTED;
goto out;
}
+ if ((data_size == 0) || !(attributes & ACCESS_ATTR)) {
+ /* delete the variable: */
+ env_set(native_name, NULL);
+ ret = EFI_SUCCESS;
+ 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(old_val, "(blob)")) {
+ return EFI_DEVICE_ERROR;
+ goto out;
+ }
+ old_size = strlen(old_val);
+ } else {
+ old_size = 0;
+ }
+ } else {
+ if ((data_size == 0) || !(attributes & ACCESS_ATTR) ||
+ (attributes & EFI_VARIABLE_APPEND_WRITE)) {
+ /* delete, but nothing to do */
+ ret = EFI_NOT_FOUND;
+ goto out;
+ }
+
+ old_size = 0;
}
- val = malloc(2 * data_size + strlen("{ro,run,boot,nv}(blob)") + 1);
+ val = malloc(old_size + 2 * data_size
+ + strlen("{ro,run,boot,nv}(blob)") + 1);
if (!val) {
ret = EFI_OUT_OF_RESOURCES;
goto out;
@@ -481,10 +497,7 @@
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 +518,13 @@
}
s += sprintf(s, "}");
+ if (old_size)
+ /* APPEND_WRITE */
+ s += sprintf(s, old_val);
+ else
+ s += sprintf(s, "(blob)");
+
/* store payload: */
- s += sprintf(s, "(blob)");
s = bin2hex(s, data, data_size);
*s = '\0';