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 6687b69a400d724b50372653575ace95c20fa551..48ee255f879b59fc9871d920e440fecd46f473d7 100644 (file)
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -424,17 +424,17 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
                                     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 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
 
 #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;
-       }
+       old_val = env_get(native_name);
+       if (old_val) {
+               old_val = parse_attr(old_val, &attr);
 
-       val = env_get(native_name);
-       if (val) {
-               parse_attr(val, &attr);
-
-               /* We should not free val */
-               val = NULL;
+               /* check read-only first */
                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) {
+               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 */
+               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 @@ 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 +518,13 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
        }
        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';