efi_selftest: ask before overwriting in dtbdump.efi

Before overwriting an existing file ask the user.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

diff --git a/lib/efi_selftest/dtbdump.c b/lib/efi_selftest/dtbdump.c
index efef759..cbc9067 100644 (file)
--- a/lib/efi_selftest/dtbdump.c
+++ b/lib/efi_selftest/dtbdump.c
@@ -41,7 +41,51 @@ static void error(u16 *string)
 }
 
 /**
- * input() - read string from console
+ * efi_input_yn() - get answer to yes/no question
+ *
+ * Return:
+ * y or Y
+ *     EFI_SUCCESS
+ * n or N
+ *     EFI_ACCESS_DENIED
+ * ESC
+ *     EFI_ABORTED
+ */
+static efi_status_t efi_input_yn(void)
+{
+       struct efi_input_key key = {0};
+       efi_uintn_t index;
+       efi_status_t ret;
+
+       /* Drain the console input */
+       ret = cin->reset(cin, true);
+       for (;;) {
+               ret = bs->wait_for_event(1, &cin->wait_for_key, &index);
+               if (ret != EFI_SUCCESS)
+                       continue;
+               ret = cin->read_key_stroke(cin, &key);
+               if (ret != EFI_SUCCESS)
+                       continue;
+               switch (key.scan_code) {
+               case 0x17: /* Escape */
+                       return EFI_ABORTED;
+               default:
+                       break;
+               }
+               /* Convert to lower case */
+               switch (key.unicode_char | 0x20) {
+               case 'y':
+                       return EFI_SUCCESS;
+               case 'n':
+                       return EFI_ACCESS_DENIED;
+               default:
+                       break;
+               }
+       }
+}
+
+/**
+ * efi_input() - read string from console
  *
  * @buffer:            input buffer
  * @buffer_size:       buffer size
@@ -379,6 +423,20 @@ efi_status_t do_save(u16 *filename)
                error(L"Failed to open volume\n");
                return ret;
        }
+       /* Check if file already exists */
+       ret = root->open(root, &file, filename, EFI_FILE_MODE_READ, 0);
+       if (ret == EFI_SUCCESS) {
+               file->close(file);
+               cout->output_string(cout, L"Overwrite existing file (y/n)? ");
+               ret = efi_input_yn();
+               cout->output_string(cout, L"\n");
+               if (ret != EFI_SUCCESS) {
+                       root->close(root);
+                       error(L"Aborted by user\n");
+                       return ret;
+               }
+       }
+
        /* Create file */
        ret = root->open(root, &file, filename,
                         EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE |