Add device open/close.

src/tlcl/tlcl.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.
  */
 
 /* A lightweight TPM command library.
  *
  * The general idea is that TPM commands are array of bytes whose fields are
  * mostly compile-time constant.  The goal is to build much of the commands at
  * compile time (or build time) and change some of the fields at run time as
@@ skipping 21 matching lines @@
 #endif  /* FIRMWARE */
 
 #include "structures.h"
 #include "tlcl_internal.h"
 #include "version.h"
 
 #if USE_TPM_EMULATOR
 #include "tpmemu.h"
 #endif
 
+#define TPM_DEVICE_PATH "/dev/tpm0"
+
 /* The file descriptor for the TPM device.
  */
 int tpm_fd = -1;
 
 /* Log level.  0 is quietest.  Be verbose by default.
  */
 int tlcl_log_level = 1;
 
 /* Print |n| bytes from array |a|, with newlines.
  */
@@ skipping 172 matching lines @@
 }
 
 void TlclSetLogLevel(int level) {
   tlcl_log_level = level;
 }
 
 void TlclLibInit(void) {
 #if USE_TPM_EMULATOR
   tpmemu_init();
 #else
-#if !FIRMWARE
-  tpm_fd = open("/dev/tpm0", O_RDWR);
-  if (tpm_fd < 0) {
-    error("cannot open TPM device: %s\n", strerror(errno));
-  }
-#endif  /* !FIRMWARE */
+  TlclOpenDevice();
 #endif  /* USE_TPM_EMULATOR */
 }
 
+void TlclCloseDevice(void) {
+#if !FIRMWARE
+  close(tpm_fd);
+  tpm_fd = -1;
+#endif  /* !FIRMWARE */
+}
+
+void TlclOpenDevice(void) {
+#if !FIRMWARE
+  tpm_fd = open(TPM_DEVICE_PATH, O_RDWR);
+  if (tpm_fd < 0) {
+    error("cannot open TPM device %s: %s\n", TPM_DEVICE_PATH, strerror(errno));
+  }
+#endif  /* !FIRMWARE */
+}
+
 uint32_t TlclStartup(void) {
   return Send(tpm_startup_cmd.buffer);
 }
 
 uint32_t TlclSelftestfull(void) {
   return Send(tpm_selftestfull_cmd.buffer);
 }
 
 uint32_t TlclContinueSelfTest(void) {
   return Send(tpm_continueselftest_cmd.buffer);
@@ skipping 138 matching lines @@
   ToTpmUint32(tpm_getpermissions_cmd.index, index);
   SendReceive(tpm_getpermissions_cmd.buffer, response, sizeof(response));
   result = TpmReturnCode(response);
   if (result != TPM_SUCCESS) {
     return result;
   }
   nvdata = response + kTpmResponseHeaderLength + sizeof(size);
   FromTpmUint32(nvdata + kNvDataPublicPermissionsOffset, permissions);
   return result;
 }