vboot TPM stub functions return error codes

firmware/stub/tpm_lite_stub.c

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * Stub implementations of utility functions which call their linux-specific
  * equivalents.
  */
 
 #define _STUB_IMPLEMENTATION_
 #include "tlcl.h"
@@ skipping 81 matching lines @@
 
 /* Gets the size field of a TPM command.
  */
 POSSIBLY_UNUSED static INLINE int TpmResponseSize(const uint8_t* buffer) {
   uint32_t size;
   FromTpmUint32(buffer + sizeof(uint16_t), &size);
   return (int) size;
 }
 
 
-void TlclStubInit(void) {
-  TlclOpenDevice();
+uint32_t TlclStubInit(void) {
+  return TlclOpenDevice();
 }
 
 
-void TlclCloseDevice(void) {
-  close(tpm_fd);
-  tpm_fd = -1;
+uint32_t TlclCloseDevice(void) {
+  if (tpm_fd != -1) {
+    close(tpm_fd);
+    tpm_fd = -1;
+  }
+  return 0;
 }
 
 
-void TlclOpenDevice(void) {
+uint32_t TlclOpenDevice(void) {
   char* device_path;
 
   if (tpm_fd >= 0)
-    return;  /* Already open */
+    return 0;  /* Already open */
 
   device_path = getenv("TPM_DEVICE_PATH");
   if (device_path == NULL) {
     device_path = TPM_DEVICE_PATH;
   }
 
   tpm_fd = open(device_path, O_RDWR);
   if (tpm_fd < 0) {
-    error("cannot open TPM device %s: %s\n", device_path, strerror(errno));
+    VBDEBUG(("TPM: Cannot open TPM device %s: %s\n", device_path,
+             strerror(errno)));
+    return TPM_E_IOERROR;
   }
+
+  return 0;
 }
 
 
 uint32_t TlclStubSendReceive(const uint8_t* request, int request_length,
                              uint8_t* response, int max_length) {
   /*
    * In a real firmware implementation, this function should contain
    * the equivalent API call for the firmware TPM driver which takes a
    * raw sequence of bytes as input command and a pointer to the
    * output buffer for putting in the results.
@@ skipping 40 matching lines @@
     (tag == TPM_TAG_RQU_COMMAND &&
      response_tag == TPM_TAG_RSP_COMMAND) ||
     (tag == TPM_TAG_RQU_AUTH1_COMMAND &&
      response_tag == TPM_TAG_RSP_AUTH1_COMMAND) ||
     (tag == TPM_TAG_RQU_AUTH2_COMMAND &&
      response_tag == TPM_TAG_RSP_AUTH2_COMMAND));
   assert(response_length == TpmResponseSize(response));
 
   return 0;  /* Success */
 }