Split libvboot_host.a into external and local libraries.

We've been creating and linking against a library called "libvboot_host.a"
for two different reasons. The main purpose is to build the vboot_reference
tools found in the utility/ directory. But there are some external userspace
programs that would also like to use some functions in this library.

This change establishes libvboot_host.a as the library for use by external
userspace programs only, and creates a new libvboot_util.a library that's
only used inside this source tree to build the vboot utilities.

BUG=chromium:231567
BRANCH=ToT
TEST=manual

Build and run the local tests:

  make runalltests
  make clean

Build Link firmware and all the utilities:

  emerge-link chromeos-base/vboot_reference \
              sys-boot/depthcharge \
              sys-boot/coreboot \
              chromeos-base/chromeos-ec \
              chromeos-base/chromeos-firmware-link \
              chromeos-base/chromeos-cryptohome \
              chromeos-base/update_engine \
              chromeos-base/chromeos-installer \
              chromeos-base/chromeos-login \
              chromeos-base/verity

Build Lumpy utilities, which include the 32-bit cros_installer:

  emerge-lumpy chromeos-base/vboot_reference \
               chromeos-base/chromeos-login \
               chromeos-base/verity \
               chromeos-base/update_engine \
               chromeos-base/chromeos-installer \
               chromeos-base/chromeos-cryptohome

Change-Id: Ie81ff1f74a6356cb8fab7d98471139d7758c4f19
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/207016
Reviewed-by: Randall Spangler <rspangler@chromium.org>

15 files changed, 319 insertions, 165 deletions

diff --git a/Makefile b/Makefile
index 2fb59cc8..dff0a386 100644
--- a/Makefile
+++ b/Makefile
@@ -237,7 +237,9 @@ else
 INCLUDES += -Ifirmware/arch/${FIRMWARE_ARCH}/include
 endif
 
-# Firmware library. TODO: Do we still need to export this?
+# Firmware library, used by the other firmware components (depthcharge,
+# coreboot, etc.). It doesn't need exporting to some other place; they'll build
+# this source tree locally and link to it directly.
 FWLIB = ${BUILD}/vboot_fw.a
 
 # Smaller firmware library. TODO: Do we still need to export this?
@@ -252,6 +254,7 @@ VBINIT_SRCS = \
 	firmware/lib/vboot_api_init.c \
 	firmware/lib/vboot_common_init.c \
 	firmware/lib/vboot_nvstorage.c \
+	firmware/lib/vboot_nvstorage_rollback.c \
 	firmware/lib/region-init.c \
 
 # Additional firmware library sources needed by VbSelectFirmware() call
@@ -348,10 +351,10 @@ endif
 
 ALL_OBJS += ${FWLIB_OBJS} ${FWLIB2_OBJS} ${VBINIT_OBJS} ${VBSF_OBJS}
 
-# Library to build the utilities. "HOST" mostly means "userspace".
-HOSTLIB = ${BUILD}/libvboot_host.a
+# Intermediate library for the vboot_reference utilities to link against.
+UTILLIB = ${BUILD}/libvboot_util.a
 
-HOSTLIB_SRCS = \
+UTILLIB_SRCS = \
 	cgpt/cgpt_create.c \
 	cgpt/cgpt_add.c \
 	cgpt/cgpt_boot.c \
@@ -370,37 +373,63 @@ HOSTLIB_SRCS = \
 	host/lib/host_key.c \
 	host/lib/host_keyblock.c \
 	host/lib/host_misc.c \
+	host/lib/util_misc.c \
 	host/lib/host_signature.c \
 	host/lib/signature_digest.c \
 	utility/dump_kernel_config_lib.c
 
+UTILLIB_OBJS = ${UTILLIB_SRCS:%.c=${BUILD}/%.o}
+ALL_OBJS += ${UTILLIB_OBJS}
+
+# Externally exported library for some target userspace apps to link with
+# (cryptohome, updater, etc.)
+HOSTLIB = ${BUILD}/libvboot_host.a
+
+HOSTLIB_SRCS = \
+	cgpt/cgpt_add.c \
+	cgpt/cgpt_boot.c \
+	cgpt/cgpt_common.c \
+	cgpt/cgpt_create.c \
+	cgpt/cgpt_prioritize.c \
+	cgpt/flash_ts_drv.c \
+	firmware/lib/cgptlib/cgptlib_internal.c \
+	firmware/lib/cgptlib/crc32.c \
+	firmware/lib/cgptlib/mtdlib.c \
+	firmware/lib/crc8.c \
+	firmware/lib/flash_ts.c \
+	firmware/lib/tpm_lite/tlcl.c \
+	firmware/lib/utility_string.c \
+	firmware/lib/vboot_nvstorage.c \
+	firmware/stub/tpm_lite_stub.c \
+	firmware/stub/utility_stub.c \
+	firmware/stub/vboot_api_stub_init.c \
+	host/arch/${ARCH}/lib/crossystem_arch.c \
+	host/lib/crossystem.c \
+	host/lib/host_misc.c \
+	utility/dump_kernel_config_lib.c
+
 HOSTLIB_OBJS = ${HOSTLIB_SRCS:%.c=${BUILD}/%.o}
 ALL_OBJS += ${HOSTLIB_OBJS}
 
-# Might need this too.
-CRYPTO_LIBS := $(shell ${PKG_CONFIG} --libs libcrypto)
-
 # Sigh. For historical reasons, the autoupdate installer must sometimes be a
 # 32-bit executable, even when everything else is 64-bit. But it only needs a
 # few functions, so let's just build those.
 TINYHOSTLIB = ${BUILD}/libtinyvboot_host.a
 
 TINYHOSTLIB_SRCS = \
-	cgpt/cgpt_create.c \
 	cgpt/cgpt_add.c \
 	cgpt/cgpt_boot.c \
-	cgpt/cgpt_show.c \
-	cgpt/cgpt_repair.c \
-	cgpt/cgpt_prioritize.c \
 	cgpt/cgpt_common.c \
+	cgpt/cgpt_create.c \
+	cgpt/cgpt_prioritize.c \
 	cgpt/flash_ts_drv.c \
+	firmware/lib/cgptlib/cgptlib_internal.c \
+	firmware/lib/cgptlib/crc32.c \
 	firmware/lib/cgptlib/mtdlib.c \
 	firmware/lib/flash_ts.c \
-	utility/dump_kernel_config_lib.c \
-	firmware/lib/cgptlib/crc32.c \
-	firmware/lib/cgptlib/cgptlib_internal.c \
 	firmware/lib/utility_string.c \
-	firmware/stub/utility_stub.c
+	firmware/stub/utility_stub.c \
+	utility/dump_kernel_config_lib.c
 
 TINYHOSTLIB_OBJS = ${TINYHOSTLIB_SRCS:%.c=${BUILD}/%.o}
 
@@ -657,7 +686,7 @@ all: fwlib $(if ${VBOOT2},fwlib2) $(if ${FIRMWARE_ARCH},,host_stuff) \
 
 # Host targets
 .PHONY: host_stuff
-host_stuff: hostlib cgpt utils futil tests
+host_stuff: utillib cgpt utils futil hostlib tests
 
 .PHONY: clean
 clean:
@@ -754,24 +783,43 @@ ${FWLIB2}: ${FWLIB2_OBJS}
 	${Q}ar qc $@ $^
 
 # ----------------------------------------------------------------------------
-# Host library
-
-
-# Link tests
-${BUILD}/host/linktest/main: ${HOSTLIB}
-${BUILD}/host/linktest/main: LIBS = ${HOSTLIB}
-ALL_OBJS += ${BUILD}/host/linktest/main.o
-
-.PHONY: hostlib
-hostlib: ${BUILD}/host/linktest/main
+# Host library(s)
 
-${BUILD}/host/% ${HOSTLIB}: INCLUDES += \
+# Link tests for local utilities
+${BUILD}/host/linktest/main: ${UTILLIB}
+${BUILD}/host/linktest/main: INCLUDES += \
 	-Ihost/include \
 	-Ihost/arch/${ARCH}/include \
 	-Ihost/lib/include
+${BUILD}/host/linktest/main: LIBS = ${UTILLIB}
+ALL_OBJS += ${BUILD}/host/linktest/main.o
+
+.PHONY: utillib
+utillib: ${UTILLIB} \
+	${BUILD}/host/linktest/main
 
 # TODO: better way to make .a than duplicating this recipe each time?
-${HOSTLIB}: ${HOSTLIB_OBJS} ${FWLIB_OBJS} $(if ${VBOOT2},${FWLIB2_OBJS})
+${UTILLIB}: ${UTILLIB_OBJS} ${FWLIB_OBJS} $(if ${VBOOT2},${FWLIB2_OBJS})
+	@$(PRINTF) "    RM            $(subst ${BUILD}/,,$@)\n"
+	${Q}rm -f $@
+	@$(PRINTF) "    AR            $(subst ${BUILD}/,,$@)\n"
+	${Q}ar qc $@ $^
+
+
+# Link tests for external repos
+${BUILD}/host/linktest/extern: ${HOSTLIB}
+${BUILD}/host/linktest/extern: INCLUDES += -Ihost/include
+${BUILD}/host/linktest/extern: LIBS = ${HOSTLIB}
+${BUILD}/host/linktest/extern: LDLIBS += -static
+ALL_OBJS += ${BUILD}/host/linktest/extern.o
+
+.PHONY: hostlib
+hostlib: ${HOSTLIB} \
+	${BUILD}/host/linktest/extern
+
+# TODO: better way to make .a than duplicating this recipe each time?
+${HOSTLIB}: INCLUDES += -Ihost/include -Ihost/lib/include
+${HOSTLIB}: ${HOSTLIB_OBJS}
 	@$(PRINTF) "    RM            $(subst ${BUILD}/,,$@)\n"
 	${Q}rm -f $@
 	@$(PRINTF) "    AR            $(subst ${BUILD}/,,$@)\n"
@@ -783,6 +831,7 @@ ${HOSTLIB}: ${HOSTLIB_OBJS} ${FWLIB_OBJS} $(if ${VBOOT2},${FWLIB2_OBJS})
 tinyhostlib: ${TINYHOSTLIB}
 	${Q}cp -f ${TINYHOSTLIB} ${HOSTLIB}
 
+${TINYHOSTLIB}: INCLUDES += -Ihost/include -Ihost/lib/include
 ${TINYHOSTLIB}: ${TINYHOSTLIB_OBJS}
 	@$(PRINTF) "    RM            $(subst ${BUILD}/,,$@)\n"
 	${Q}rm -f $@
@@ -800,7 +849,7 @@ ${CGPT_OBJS}: INCLUDES += -Ihost/include
 ${CGPT}: LDFLAGS += -static
 ${CGPT}: LDLIBS += -luuid
 
-${CGPT}: ${CGPT_OBJS} ${HOSTLIB}
+${CGPT}: ${CGPT_OBJS} ${UTILLIB}
 	@$(PRINTF) "    LDcgpt        $(subst ${BUILD}/,,$@)\n"
 	${Q}${LD} -o ${CGPT} ${CFLAGS} ${LDFLAGS} $^ ${LDLIBS}
 
@@ -828,8 +877,8 @@ utils: ${UTIL_BINS} ${UTIL_SCRIPTS}
 	${Q}cp -f ${UTIL_SCRIPTS} ${BUILD}/utility
 	${Q}chmod a+rx $(patsubst %,${BUILD}/%,${UTIL_SCRIPTS})
 
-${UTIL_BINS} ${UTIL_BINS_STATIC}: ${HOSTLIB}
-${UTIL_BINS} ${UTIL_BINS_STATIC}: LIBS = ${HOSTLIB}
+${UTIL_BINS} ${UTIL_BINS_STATIC}: ${UTILLIB}
+${UTIL_BINS} ${UTIL_BINS_STATIC}: LIBS = ${UTILLIB}
 
 .PHONY: utils_install
 utils_install: ${UTIL_BINS} ${UTIL_SCRIPTS}
@@ -874,12 +923,12 @@ futil_install: ${FUTIL_BIN}
 		ln -sf futility "${F_DIR}/$$prog"; done
 
 # TODO(wfrichar): This will need some refactoring (crbug.com/228932)
-${BUILD}/futility/% ${HOSTLIB}: INCLUDES += \
+${BUILD}/futility/% ${UTILLIB}: INCLUDES += \
 	-Ihost/include \
 	-Ihost/arch/${ARCH}/include \
 	-Ihost/lib/include
-${FUTIL_STATIC_BIN} ${FUTIL_BIN}: ${HOSTLIB}
-${FUTIL_STATIC_BIN} ${FUTIL_BIN}: LIBS = ${HOSTLIB}
+${FUTIL_STATIC_BIN} ${FUTIL_BIN}: ${UTILLIB}
+${FUTIL_STATIC_BIN} ${FUTIL_BIN}: LIBS = ${UTILLIB}
 
 # ----------------------------------------------------------------------------
 # Utility to generate TLCL structure definition header file.
@@ -903,9 +952,9 @@ update_tlcl_structures: ${BUILD}/utility/tlcl_generator
 .PHONY: tests
 tests: ${TEST_BINS}
 
-${TEST_BINS}: ${HOSTLIB} ${TESTLIB}
+${TEST_BINS}: ${UTILLIB} ${TESTLIB}
 ${TEST_BINS}: INCLUDES += -Itests
-${TEST_BINS}: LIBS = ${HOSTLIB} ${TESTLIB}
+${TEST_BINS}: LIBS = ${UTILLIB} ${TESTLIB}
 
 ${TESTLIB}: ${TESTLIB_OBJS}
 	@$(PRINTF) "    RM            $(subst ${BUILD}/,,$@)\n"
@@ -955,6 +1004,8 @@ ${FUTIL_BIN}: LDFLAGS += -fuse-ld=bfd
 ${FUTIL_STATIC_BIN}: LDFLAGS += -fuse-ld=bfd
 
 # Some utilities need external crypto functions
+CRYPTO_LIBS := $(shell ${PKG_CONFIG} --libs libcrypto)
+
 ${BUILD}/utility/dumpRSAPublicKey: LDLIBS += ${CRYPTO_LIBS}
 ${BUILD}/utility/pad_digest_utility: LDLIBS += ${CRYPTO_LIBS}
 ${BUILD}/utility/signature_digest_utility: LDLIBS += ${CRYPTO_LIBS}
@@ -1157,6 +1208,9 @@ endif
 #	${BUILD}/tests/firmware_rollback_tests
 #	${BUILD}/tests/kernel_rollback_tests
 
+.PHONY: runalltests
+runalltests: runtests runfutiltests runlongtests
+
 # Code coverage
 .PHONY: coverage_init
 coverage_init: test_setup
diff --git a/cgpt/cgpt_common.c b/cgpt/cgpt_common.c
index c8a069a4..ff3ae696 100644
--- a/cgpt/cgpt_common.c
+++ b/cgpt/cgpt_common.c
@@ -1162,6 +1162,42 @@ uint8_t RepairHeader(GptData *gpt, const uint32_t valid_headers) {
   return 0;
 }
 
+int CgptGetNumNonEmptyPartitions(CgptShowParams *params) {
+  struct drive drive;
+  int gpt_retval;
+  int retval;
+
+  if (params == NULL)
+    return CGPT_FAILED;
+
+  if (CGPT_OK != DriveOpen(params->drive_name, &drive, O_RDONLY))
+    return CGPT_FAILED;
+
+  if (GPT_SUCCESS != (gpt_retval = GptSanityCheck(&drive.gpt))) {
+    Error("GptSanityCheck() returned %d: %s\n",
+          gpt_retval, GptError(gpt_retval));
+    retval = CGPT_FAILED;
+    goto done;
+  }
+
+  params->num_partitions = 0;
+  int numEntries = GetNumberOfEntries(&drive);
+  int i;
+  for(i = 0; i < numEntries; i++) {
+      GptEntry *entry = GetEntry(&drive.gpt, ANY_VALID, i);
+      if (GuidIsZero(&entry->type))
+        continue;
+
+      params->num_partitions++;
+  }
+
+  retval = CGPT_OK;
+
+done:
+  DriveClose(&drive, 0);
+  return retval;
+}
+
 int GuidEqual(const Guid *guid1, const Guid *guid2) {
   return (0 == memcmp(guid1, guid2, sizeof(Guid)));
 }
diff --git a/cgpt/cgpt_show.c b/cgpt/cgpt_show.c
index 082a5c73..a2b7c951 100644
--- a/cgpt/cgpt_show.c
+++ b/cgpt/cgpt_show.c
@@ -219,42 +219,6 @@ void EntriesDetails(struct drive *drive, const int secondary, int raw) {
   }
 }
 
-int CgptGetNumNonEmptyPartitions(CgptShowParams *params) {
-  struct drive drive;
-  int gpt_retval;
-  int retval;
-
-  if (params == NULL)
-    return CGPT_FAILED;
-
-  if (CGPT_OK != DriveOpen(params->drive_name, &drive, O_RDONLY))
-    return CGPT_FAILED;
-
-  if (GPT_SUCCESS != (gpt_retval = GptSanityCheck(&drive.gpt))) {
-    Error("GptSanityCheck() returned %d: %s\n",
-          gpt_retval, GptError(gpt_retval));
-    retval = CGPT_FAILED;
-    goto done;
-  }
-
-  params->num_partitions = 0;
-  int numEntries = GetNumberOfEntries(&drive);
-  int i;
-  for(i = 0; i < numEntries; i++) {
-      GptEntry *entry = GetEntry(&drive.gpt, ANY_VALID, i);
-      if (GuidIsZero(&entry->type))
-        continue;
-
-      params->num_partitions++;
-  }
-
-  retval = CGPT_OK;
-
-done:
-  DriveClose(&drive, 0);
-  return retval;
-}
-
 int MtdShow(struct drive *drive, CgptShowParams *params) {
   if (params->partition) {                      // show single partition
     if (params->partition > GetNumberOfEntries(drive)) {
diff --git a/firmware/lib/vboot_nvstorage.c b/firmware/lib/vboot_nvstorage.c
index 3c5d1e27..5476e85b 100644
--- a/firmware/lib/vboot_nvstorage.c
+++ b/firmware/lib/vboot_nvstorage.c
@@ -7,10 +7,8 @@
  */
 #include "sysincludes.h"
 
-
 #include "crc8.h"
 #include "utility.h"
-#include "rollback_index.h"
 #include "vboot_common.h"
 #include "vboot_nvstorage.h"
 
@@ -343,81 +341,3 @@ int VbNvSet(VbNvContext *context, VbNvParam param, uint32_t value)
 	context->regenerate_crc = 1;
 	return 0;
 }
-
-/* These are the fields of the nvram that we want to back up. */
-static const VbNvParam backup_params[] = {
-	VBNV_KERNEL_FIELD,
-	VBNV_LOCALIZATION_INDEX,
-	VBNV_DEV_BOOT_USB,
-	VBNV_DEV_BOOT_LEGACY,
-	VBNV_DEV_BOOT_SIGNED_ONLY,
-};
-
-/* We can't back things up if there isn't enough storage. */
-BUILD_ASSERT(VBNV_BLOCK_SIZE <= BACKUP_NV_SIZE);
-
-int RestoreNvFromBackup(VbNvContext *vnc)
-{
-	VbNvContext bvnc;
-	uint32_t value;
-	int i;
-
-	VBDEBUG(("TPM: %s()\n", __func__));
-
-	if (TPM_SUCCESS != RollbackBackupRead(bvnc.raw))
-		return 1;
-
-	VbNvSetup(&bvnc);
-	if (bvnc.regenerate_crc) {
-		VBDEBUG(("TPM: Oops, backup is no good.\n"));
-		return 1;
-	}
-
-	for (i = 0; i < ARRAY_SIZE(backup_params); i++) {
-		VbNvGet(&bvnc, backup_params[i], &value);
-		VbNvSet(vnc, backup_params[i], value);
-	}
-
-	/* VbNvTeardown(&bvnc); is not needed. We're done with it. */
-	return 0;
-}
-
-int SaveNvToBackup(VbNvContext *vnc)
-{
-	VbNvContext bvnc;
-	uint32_t value;
-	int i;
-
-	VBDEBUG(("TPM: %s()\n", __func__));
-
-	/* Read it first. No point in writing the same data. */
-	if (TPM_SUCCESS != RollbackBackupRead(bvnc.raw))
-		return 1;
-
-	VbNvSetup(&bvnc);
-	VBDEBUG(("TPM: existing backup is %s\n",
-		 bvnc.regenerate_crc ? "bad" : "good"));
-
-	for (i = 0; i < ARRAY_SIZE(backup_params); i++) {
-		VbNvGet(vnc, backup_params[i], &value);
-		VbNvSet(&bvnc, backup_params[i], value);
-	}
-
-	VbNvTeardown(&bvnc);
-
-	if (!bvnc.raw_changed) {
-		VBDEBUG(("TPM: Nothing's changed, not writing backup\n"));
-		/* Clear the request flag, since we're happy. */
-		VbNvSet(vnc, VBNV_BACKUP_NVRAM_REQUEST, 0);
-		return 0;
-	}
-
-	if (TPM_SUCCESS == RollbackBackupWrite(bvnc.raw)) {
-		/* Clear the request flag if we wrote successfully too */
-		VbNvSet(vnc, VBNV_BACKUP_NVRAM_REQUEST, 0);
-		return 0;
-	}
-
-	VBDEBUG(("TPM: Sorry, couldn't write backup.\n"));
-	return 1;
-}
diff --git a/firmware/lib/vboot_nvstorage_rollback.c b/firmware/lib/vboot_nvstorage_rollback.c
new file mode 100644
index 00000000..8e67812d
--- /dev/null
+++ b/firmware/lib/vboot_nvstorage_rollback.c
@@ -0,0 +1,92 @@
+/* Copyright (c) 2014 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.
+ */
+
+/* Non-volatile storage routines.
+ */
+#include "sysincludes.h"
+
+#include "crc8.h"
+#include "utility.h"
+#include "vboot_common.h"
+#include "vboot_nvstorage.h"
+#include "rollback_index.h"
+
+/* These are the fields of the nvram that we want to back up. */
+static const VbNvParam backup_params[] = {
+	VBNV_KERNEL_FIELD,
+	VBNV_LOCALIZATION_INDEX,
+	VBNV_DEV_BOOT_USB,
+	VBNV_DEV_BOOT_LEGACY,
+	VBNV_DEV_BOOT_SIGNED_ONLY,
+};
+
+/* We can't back things up if there isn't enough storage. */
+BUILD_ASSERT(VBNV_BLOCK_SIZE <= BACKUP_NV_SIZE);
+
+int RestoreNvFromBackup(VbNvContext *vnc)
+{
+	VbNvContext bvnc;
+	uint32_t value;
+	int i;
+
+	VBDEBUG(("TPM: %s()\n", __func__));
+
+	if (TPM_SUCCESS != RollbackBackupRead(bvnc.raw))
+		return 1;
+
+	VbNvSetup(&bvnc);
+	if (bvnc.regenerate_crc) {
+		VBDEBUG(("TPM: Oops, backup is no good.\n"));
+		return 1;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(backup_params); i++) {
+		VbNvGet(&bvnc, backup_params[i], &value);
+		VbNvSet(vnc, backup_params[i], value);
+	}
+
+	/* VbNvTeardown(&bvnc); is not needed. We're done with it. */
+	return 0;
+}
+
+int SaveNvToBackup(VbNvContext *vnc)
+{
+	VbNvContext bvnc;
+	uint32_t value;
+	int i;
+
+	VBDEBUG(("TPM: %s()\n", __func__));
+
+	/* Read it first. No point in writing the same data. */
+	if (TPM_SUCCESS != RollbackBackupRead(bvnc.raw))
+		return 1;
+
+	VbNvSetup(&bvnc);
+	VBDEBUG(("TPM: existing backup is %s\n",
+		 bvnc.regenerate_crc ? "bad" : "good"));
+
+	for (i = 0; i < ARRAY_SIZE(backup_params); i++) {
+		VbNvGet(vnc, backup_params[i], &value);
+		VbNvSet(&bvnc, backup_params[i], value);
+	}
+
+	VbNvTeardown(&bvnc);
+
+	if (!bvnc.raw_changed) {
+		VBDEBUG(("TPM: Nothing's changed, not writing backup\n"));
+		/* Clear the request flag, since we're happy. */
+		VbNvSet(vnc, VBNV_BACKUP_NVRAM_REQUEST, 0);
+		return 0;
+	}
+
+	if (TPM_SUCCESS == RollbackBackupWrite(bvnc.raw)) {
+		/* Clear the request flag if we wrote successfully too */
+		VbNvSet(vnc, VBNV_BACKUP_NVRAM_REQUEST, 0);
+		return 0;
+	}
+
+	VBDEBUG(("TPM: Sorry, couldn't write backup.\n"));
+	return 1;
+}
diff --git a/host/lib/host_misc.c b/host/lib/host_misc.c
index 77466864..110feee0 100644
--- a/host/lib/host_misc.c
+++ b/host/lib/host_misc.c
@@ -114,13 +114,3 @@ int WriteFile(const char* filename, const void *data, uint64_t size) {
   fclose(f);
   return 0;
 }
-
-void PrintPubKeySha1Sum(VbPublicKey* key) {
-  uint8_t* buf = ((uint8_t *)key) + key->key_offset;
-  uint64_t buflen = key->key_size;
-  uint8_t* digest = DigestBuf(buf, buflen, SHA1_DIGEST_ALGORITHM);
-  int i;
-  for (i=0; i<SHA1_DIGEST_SIZE; i++)
-    printf("%02x", digest[i]);
-  free(digest);
-}
diff --git a/host/lib/include/host_misc.h b/host/lib/include/host_misc.h
index 22b31415..9bfa721d 100644
--- a/host/lib/include/host_misc.h
+++ b/host/lib/include/host_misc.h
@@ -43,7 +43,4 @@ int ReadFileBit(const char* filename, int bitmask);
  * Returns 0 if success, 1 if error. */
 int WriteFile(const char* filename, const void *data, uint64_t size);
 
-/* Prints the sha1sum of the given VbPublicKey to stdout. */
-void PrintPubKeySha1Sum(VbPublicKey* key);
-
 #endif  /* VBOOT_REFERENCE_HOST_MISC_H_ */
diff --git a/host/lib/include/util_misc.h b/host/lib/include/util_misc.h
new file mode 100644
index 00000000..788929de
--- /dev/null
+++ b/host/lib/include/util_misc.h
@@ -0,0 +1,16 @@
+/* Copyright (c) 2014 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.
+ *
+ * Host-side misc functions for verified boot.
+ */
+
+#ifndef VBOOT_REFERENCE_UTIL_MISC_H_
+#define VBOOT_REFERENCE_UTIL_MISC_H_
+
+#include "vboot_struct.h"
+
+/* Prints the sha1sum of the given VbPublicKey to stdout. */
+void PrintPubKeySha1Sum(VbPublicKey* key);
+
+#endif  /* VBOOT_REFERENCE_UTIL_MISC_H_ */
diff --git a/host/lib/util_misc.c b/host/lib/util_misc.c
new file mode 100644
index 00000000..09df8eef
--- /dev/null
+++ b/host/lib/util_misc.c
@@ -0,0 +1,26 @@
+/* Copyright (c) 2014 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.
+ *
+ * Miscellaneous functions for userspace vboot utilities.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "cryptolib.h"
+#include "host_common.h"
+#include "util_misc.h"
+#include "vboot_common.h"
+
+void PrintPubKeySha1Sum(VbPublicKey* key) {
+  uint8_t* buf = ((uint8_t *)key) + key->key_offset;
+  uint64_t buflen = key->key_size;
+  uint8_t* digest = DigestBuf(buf, buflen, SHA1_DIGEST_ALGORITHM);
+  int i;
+  for (i=0; i<SHA1_DIGEST_SIZE; i++)
+    printf("%02x", digest[i]);
+  free(digest);
+}
diff --git a/host/linktest/extern.c b/host/linktest/extern.c
new file mode 100644
index 00000000..46b5ddac
--- /dev/null
+++ b/host/linktest/extern.c
@@ -0,0 +1,50 @@
+/* Copyright (c) 2014 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.
+ */
+
+/*
+ * This tests for the presence of those functions actually used by userspace
+ * apps that are not part of firmware or vboot_reference.
+ */
+
+#include "crossystem.h"
+#include "tlcl.h"
+#include "vboot_host.h"
+
+/* TODO(crbug.com/318536) */
+const char* progname = "";
+const char* command = "";
+void (*uuid_generator)(uint8_t* buffer) = NULL;
+
+int main(void)
+{
+	/* crossystem.h */
+	VbGetSystemPropertyInt(0);
+	VbGetSystemPropertyString(0, 0, 0);
+	VbSetSystemPropertyInt(0, 0);
+
+	/* tlcl.h */
+	TlclGetOwnership(0);
+	TlclGetRandom(0, 0, 0);
+	TlclLibClose();
+	TlclLibInit();
+	TlclRead(0, 0, 0);
+
+	/* vboot_host.h */
+	CgptAdd(0);
+	CgptBoot(0);
+	CgptCreate(0);
+	CgptGetBootPartitionNumber(0);
+	CgptGetNumNonEmptyPartitions(0);
+	CgptGetPartitionDetails(0);
+	CgptPrioritize(0);
+	CgptSetAttributes(0);
+	FindKernelConfig(0, 0);
+	GuidEqual(0, 0);
+	GuidIsZero(0);
+	GuidToStr(0, 0, 0);
+	StrToGuid(0, 0);
+
+	return 0;
+}
diff --git a/host/linktest/main.c b/host/linktest/main.c
index 1f3dfecc..56ab21cd 100644
--- a/host/linktest/main.c
+++ b/host/linktest/main.c
@@ -2,6 +2,11 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
+
+/*
+ * This tests for the presence of functions used by vboot_reference utilities.
+ */
+
 #include <stdio.h>
 
 #include "host_common.h"
diff --git a/utility/vbutil_firmware.c b/utility/vbutil_firmware.c
index f6a547d6..f11d7b54 100644
--- a/utility/vbutil_firmware.c
+++ b/utility/vbutil_firmware.c
@@ -15,6 +15,7 @@
 #include "cryptolib.h"
 #include "host_common.h"
 #include "kernel_blob.h"
+#include "util_misc.h"
 #include "vboot_common.h"
 
 
diff --git a/utility/vbutil_kernel.c b/utility/vbutil_kernel.c
index 24a2ba6c..5fed77ac 100644
--- a/utility/vbutil_kernel.c
+++ b/utility/vbutil_kernel.c
@@ -23,6 +23,7 @@
 #include "cryptolib.h"
 #include "host_common.h"
 #include "kernel_blob.h"
+#include "util_misc.h"
 #include "vboot_common.h"
 
 /* Global opts */
diff --git a/utility/vbutil_key.c b/utility/vbutil_key.c
index 18e37a22..3d9dfc4a 100644
--- a/utility/vbutil_key.c
+++ b/utility/vbutil_key.c
@@ -14,6 +14,7 @@
 
 #include "cryptolib.h"
 #include "host_common.h"
+#include "util_misc.h"
 #include "vboot_common.h"
 
 
diff --git a/utility/vbutil_keyblock.c b/utility/vbutil_keyblock.c
index a26d7a99..17614580 100644
--- a/utility/vbutil_keyblock.c
+++ b/utility/vbutil_keyblock.c
@@ -13,6 +13,7 @@
 
 #include "cryptolib.h"
 #include "host_common.h"
+#include "util_misc.h"
 #include "vboot_common.h"