common/test_utils.cc - SHIFTPHONES/android_system_update_engine - Gitiles

 //
 // Copyright (C) 2012 The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //      http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //

 #include "update_engine/common/test_utils.h"

 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/loop.h>
 #include <linux/major.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/xattr.h>
 #include <unistd.h>

 #include <set>
 #include <string>
 #include <vector>

 #include <base/files/file_util.h>
 #include <base/format_macros.h>
 #include <base/logging.h>
 #include <base/strings/string_util.h>
 #include <base/strings/stringprintf.h>

 #include "update_engine/common/error_code_utils.h"
 #include "update_engine/common/utils.h"
 #include "update_engine/payload_consumer/file_writer.h"

 using base::StringPrintf;
 using std::set;
 using std::string;
 using std::vector;

 namespace chromeos_update_engine {

 void PrintTo(const Extent& extent, ::std::ostream* os) {
   *os << "(" << extent.start_block() << ", " << extent.num_blocks() << ")";
 }

 void PrintTo(const ErrorCode& error_code, ::std::ostream* os) {
   *os << utils::ErrorCodeToString(error_code);
 }

 namespace test_utils {

 const uint8_t kRandomString[] = {
   0xf2, 0xb7, 0x55, 0x92, 0xea, 0xa6, 0xc9, 0x57,
   0xe0, 0xf8, 0xeb, 0x34, 0x93, 0xd9, 0xc4, 0x8f,
   0xcb, 0x20, 0xfa, 0x37, 0x4b, 0x40, 0xcf, 0xdc,
   0xa5, 0x08, 0x70, 0x89, 0x79, 0x35, 0xe2, 0x3d,
   0x56, 0xa4, 0x75, 0x73, 0xa3, 0x6d, 0xd1, 0xd5,
   0x26, 0xbb, 0x9c, 0x60, 0xbd, 0x2f, 0x5a, 0xfa,
   0xb7, 0xd4, 0x3a, 0x50, 0xa7, 0x6b, 0x3e, 0xfd,
   0x61, 0x2b, 0x3a, 0x31, 0x30, 0x13, 0x33, 0x53,
   0xdb, 0xd0, 0x32, 0x71, 0x5c, 0x39, 0xed, 0xda,
   0xb4, 0x84, 0xca, 0xbc, 0xbd, 0x78, 0x1c, 0x0c,
   0xd8, 0x0b, 0x41, 0xe8, 0xe1, 0xe0, 0x41, 0xad,
   0x03, 0x12, 0xd3, 0x3d, 0xb8, 0x75, 0x9b, 0xe6,
   0xd9, 0x01, 0xd0, 0x87, 0xf4, 0x36, 0xfa, 0xa7,
   0x0a, 0xfa, 0xc5, 0x87, 0x65, 0xab, 0x9a, 0x7b,
   0xeb, 0x58, 0x23, 0xf0, 0xa8, 0x0a, 0xf2, 0x33,
   0x3a, 0xe2, 0xe3, 0x35, 0x74, 0x95, 0xdd, 0x3c,
   0x59, 0x5a, 0xd9, 0x52, 0x3a, 0x3c, 0xac, 0xe5,
   0x15, 0x87, 0x6d, 0x82, 0xbc, 0xf8, 0x7d, 0xbe,
   0xca, 0xd3, 0x2c, 0xd6, 0xec, 0x38, 0xeb, 0xe4,
   0x53, 0xb0, 0x4c, 0x3f, 0x39, 0x29, 0xf7, 0xa4,
   0x73, 0xa8, 0xcb, 0x32, 0x50, 0x05, 0x8c, 0x1c,
   0x1c, 0xca, 0xc9, 0x76, 0x0b, 0x8f, 0x6b, 0x57,
   0x1f, 0x24, 0x2b, 0xba, 0x82, 0xba, 0xed, 0x58,
   0xd8, 0xbf, 0xec, 0x06, 0x64, 0x52, 0x6a, 0x3f,
   0xe4, 0xad, 0xce, 0x84, 0xb4, 0x27, 0x55, 0x14,
   0xe3, 0x75, 0x59, 0x73, 0x71, 0x51, 0xea, 0xe8,
   0xcc, 0xda, 0x4f, 0x09, 0xaf, 0xa4, 0xbc, 0x0e,
   0xa6, 0x1f, 0xe2, 0x3a, 0xf8, 0x96, 0x7d, 0x30,
   0x23, 0xc5, 0x12, 0xb5, 0xd8, 0x73, 0x6b, 0x71,
   0xab, 0xf1, 0xd7, 0x43, 0x58, 0xa7, 0xc9, 0xf0,
   0xe4, 0x85, 0x1c, 0xd6, 0x92, 0x50, 0x2c, 0x98,
   0x36, 0xfe, 0x87, 0xaf, 0x43, 0x8f, 0x8f, 0xf5,
   0x88, 0x48, 0x18, 0x42, 0xcf, 0x42, 0xc1, 0xa8,
   0xe8, 0x05, 0x08, 0xa1, 0x45, 0x70, 0x5b, 0x8c,
   0x39, 0x28, 0xab, 0xe9, 0x6b, 0x51, 0xd2, 0xcb,
   0x30, 0x04, 0xea, 0x7d, 0x2f, 0x6e, 0x6c, 0x3b,
   0x5f, 0x82, 0xd9, 0x5b, 0x89, 0x37, 0x65, 0x65,
   0xbe, 0x9f, 0xa3, 0x5d,
 };

 string Readlink(const string& path) {
   vector<char> buf(PATH_MAX + 1);
   ssize_t r = readlink(path.c_str(), buf.data(), buf.size());
   if (r < 0)
     return "";
   CHECK_LT(r, static_cast<ssize_t>(buf.size()));
   return string(buf.begin(), buf.begin() + r);
 }

 bool IsXAttrSupported(const base::FilePath& dir_path) {
   char *path = strdup(dir_path.Append("xattr_test_XXXXXX").value().c_str());

   int fd = mkstemp(path);
   if (fd == -1) {
     PLOG(ERROR) << "Error creating temporary file in " << dir_path.value();
     free(path);
     return false;
   }

   if (unlink(path) != 0) {
     PLOG(ERROR) << "Error unlinking temporary file " << path;
     close(fd);
     free(path);
     return false;
   }

   int xattr_res = fsetxattr(fd, "user.xattr-test", "value", strlen("value"), 0);
   if (xattr_res != 0) {
     if (errno == ENOTSUP) {
       // Leave it to call-sites to warn about non-support.
     } else {
       PLOG(ERROR) << "Error setting xattr on " << path;
     }
   }
   close(fd);
   free(path);
   return xattr_res == 0;
 }

 bool WriteFileVector(const string& path, const brillo::Blob& data) {
   return utils::WriteFile(path.c_str(), data.data(), data.size());
 }

 bool WriteFileString(const string& path, const string& data) {
   return utils::WriteFile(path.c_str(), data.data(), data.size());
 }

 bool BindToUnusedLoopDevice(const string& filename,
                             bool writable,
                             string* out_lo_dev_name) {
   CHECK(out_lo_dev_name);
   // Get the next available loop-device.
   int control_fd =
       HANDLE_EINTR(open("/dev/loop-control", O_RDWR | O_LARGEFILE));
   TEST_AND_RETURN_FALSE_ERRNO(control_fd >= 0);
   int loop_number = ioctl(control_fd, LOOP_CTL_GET_FREE);
   IGNORE_EINTR(close(control_fd));
   *out_lo_dev_name = StringPrintf("/dev/loop%d", loop_number);

   // Double check that the loop exists and is free.
   int loop_device_fd =
       HANDLE_EINTR(open(out_lo_dev_name->c_str(), O_RDWR | O_LARGEFILE));
   if (loop_device_fd == -1 && errno == ENOENT) {
     // Workaround the case when the loop device doesn't exist.
     TEST_AND_RETURN_FALSE_ERRNO(mknod(out_lo_dev_name->c_str(),
                                       S_IFBLK | 0660,
                                       makedev(LOOP_MAJOR, loop_number)) == 0);
     loop_device_fd =
         HANDLE_EINTR(open(out_lo_dev_name->c_str(), O_RDWR | O_LARGEFILE));
   }
   TEST_AND_RETURN_FALSE_ERRNO(loop_device_fd != -1);
   ScopedFdCloser loop_device_fd_closer(&loop_device_fd);

   struct loop_info64 device_info;
   if (ioctl(loop_device_fd, LOOP_GET_STATUS64, &device_info) != -1 ||
       errno != ENXIO) {
     PLOG(ERROR) << "Loop device " << out_lo_dev_name->c_str()
                 << " already in use";
     return false;
   }

   // Open our data file and assign it to the loop device.
   int data_fd = open(filename.c_str(),
                      (writable ? O_RDWR : O_RDONLY) | O_LARGEFILE | O_CLOEXEC);
   TEST_AND_RETURN_FALSE_ERRNO(data_fd >= 0);
   ScopedFdCloser data_fd_closer(&data_fd);
   TEST_AND_RETURN_FALSE_ERRNO(ioctl(loop_device_fd, LOOP_SET_FD, data_fd) == 0);

   memset(&device_info, 0, sizeof(device_info));
   device_info.lo_offset = 0;
   device_info.lo_sizelimit = 0;  // 0 means whole file.
   device_info.lo_flags = (writable ? 0 : LO_FLAGS_READ_ONLY);
   device_info.lo_number = loop_number;
   strncpy(reinterpret_cast<char*>(device_info.lo_file_name),
           base::FilePath(filename).BaseName().value().c_str(),
           LO_NAME_SIZE - 1);
   device_info.lo_file_name[LO_NAME_SIZE - 1] = '\0';
   TEST_AND_RETURN_FALSE_ERRNO(
       ioctl(loop_device_fd, LOOP_SET_STATUS64, &device_info) == 0);
   return true;
 }

 bool UnbindLoopDevice(const string& lo_dev_name) {
   int loop_device_fd =
       HANDLE_EINTR(open(lo_dev_name.c_str(), O_RDWR | O_LARGEFILE));
   if (loop_device_fd == -1 && errno == ENOENT)
     return true;
   TEST_AND_RETURN_FALSE_ERRNO(loop_device_fd != -1);
   ScopedFdCloser loop_device_fd_closer(&loop_device_fd);

   struct loop_info64 device_info;
   // Check if the device is bound before trying to unbind it.
   int get_stat_err = ioctl(loop_device_fd, LOOP_GET_STATUS64, &device_info);
   if (get_stat_err == -1 && errno == ENXIO)
     return true;

   TEST_AND_RETURN_FALSE_ERRNO(ioctl(loop_device_fd, LOOP_CLR_FD) == 0);
   return true;
 }

 bool ExpectVectorsEq(const brillo::Blob& expected,
                      const brillo::Blob& actual) {
   EXPECT_EQ(expected.size(), actual.size());
   if (expected.size() != actual.size())
     return false;
   bool is_all_eq = true;
   for (unsigned int i = 0; i < expected.size(); i++) {
     EXPECT_EQ(expected[i], actual[i]) << "offset: " << i;
     is_all_eq = is_all_eq && (expected[i] == actual[i]);
   }
   return is_all_eq;
 }

 void FillWithData(brillo::Blob* buffer) {
   size_t input_counter = 0;
   for (uint8_t& b : *buffer) {
     b = kRandomString[input_counter];
     input_counter++;
     input_counter %= sizeof(kRandomString);
   }
 }

 ScopedLoopMounter::ScopedLoopMounter(const string& file_path,
                                      string* mnt_path,
                                      unsigned long flags) {  // NOLINT - long
   EXPECT_TRUE(temp_dir_.CreateUniqueTempDir());
   *mnt_path = temp_dir_.path().value();

   string loop_dev;
   loop_binder_.reset(
       new ScopedLoopbackDeviceBinder(file_path, true, &loop_dev));

   EXPECT_TRUE(utils::MountFilesystem(loop_dev, *mnt_path, flags, "", ""));
   unmounter_.reset(new ScopedFilesystemUnmounter(*mnt_path));
 }

 base::FilePath GetBuildArtifactsPath() {
   base::FilePath exe_path;
   base::ReadSymbolicLink(base::FilePath("/proc/self/exe"), &exe_path);
   return exe_path.DirName();
 }

 string GetBuildArtifactsPath(const string& relative_path) {
   return GetBuildArtifactsPath().Append(relative_path).value();
 }

 }  // namespace test_utils
 }  // namespace chromeos_update_engine
	//
	// Copyright (C) 2012 The Android Open Source Project
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.
	//

	#include "update_engine/common/test_utils.h"

	#include <dirent.h>
	#include <errno.h>
	#include <fcntl.h>
	#include <linux/loop.h>
	#include <linux/major.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <sys/ioctl.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <sys/xattr.h>
	#include <unistd.h>

	#include <set>
	#include <string>
	#include <vector>

	#include <base/files/file_util.h>
	#include <base/format_macros.h>
	#include <base/logging.h>
	#include <base/strings/string_util.h>
	#include <base/strings/stringprintf.h>

	#include "update_engine/common/error_code_utils.h"
	#include "update_engine/common/utils.h"
	#include "update_engine/payload_consumer/file_writer.h"

	using base::StringPrintf;
	using std::set;
	using std::string;
	using std::vector;

	namespace chromeos_update_engine {

	void PrintTo(const Extent& extent, ::std::ostream* os) {
	*os << "(" << extent.start_block() << ", " << extent.num_blocks() << ")";
	}

	void PrintTo(const ErrorCode& error_code, ::std::ostream* os) {
	*os << utils::ErrorCodeToString(error_code);
	}

	namespace test_utils {

	const uint8_t kRandomString[] = {
	0xf2, 0xb7, 0x55, 0x92, 0xea, 0xa6, 0xc9, 0x57,
	0xe0, 0xf8, 0xeb, 0x34, 0x93, 0xd9, 0xc4, 0x8f,
	0xcb, 0x20, 0xfa, 0x37, 0x4b, 0x40, 0xcf, 0xdc,
	0xa5, 0x08, 0x70, 0x89, 0x79, 0x35, 0xe2, 0x3d,
	0x56, 0xa4, 0x75, 0x73, 0xa3, 0x6d, 0xd1, 0xd5,
	0x26, 0xbb, 0x9c, 0x60, 0xbd, 0x2f, 0x5a, 0xfa,
	0xb7, 0xd4, 0x3a, 0x50, 0xa7, 0x6b, 0x3e, 0xfd,
	0x61, 0x2b, 0x3a, 0x31, 0x30, 0x13, 0x33, 0x53,
	0xdb, 0xd0, 0x32, 0x71, 0x5c, 0x39, 0xed, 0xda,
	0xb4, 0x84, 0xca, 0xbc, 0xbd, 0x78, 0x1c, 0x0c,
	0xd8, 0x0b, 0x41, 0xe8, 0xe1, 0xe0, 0x41, 0xad,
	0x03, 0x12, 0xd3, 0x3d, 0xb8, 0x75, 0x9b, 0xe6,
	0xd9, 0x01, 0xd0, 0x87, 0xf4, 0x36, 0xfa, 0xa7,
	0x0a, 0xfa, 0xc5, 0x87, 0x65, 0xab, 0x9a, 0x7b,
	0xeb, 0x58, 0x23, 0xf0, 0xa8, 0x0a, 0xf2, 0x33,
	0x3a, 0xe2, 0xe3, 0x35, 0x74, 0x95, 0xdd, 0x3c,
	0x59, 0x5a, 0xd9, 0x52, 0x3a, 0x3c, 0xac, 0xe5,
	0x15, 0x87, 0x6d, 0x82, 0xbc, 0xf8, 0x7d, 0xbe,
	0xca, 0xd3, 0x2c, 0xd6, 0xec, 0x38, 0xeb, 0xe4,
	0x53, 0xb0, 0x4c, 0x3f, 0x39, 0x29, 0xf7, 0xa4,
	0x73, 0xa8, 0xcb, 0x32, 0x50, 0x05, 0x8c, 0x1c,
	0x1c, 0xca, 0xc9, 0x76, 0x0b, 0x8f, 0x6b, 0x57,
	0x1f, 0x24, 0x2b, 0xba, 0x82, 0xba, 0xed, 0x58,
	0xd8, 0xbf, 0xec, 0x06, 0x64, 0x52, 0x6a, 0x3f,
	0xe4, 0xad, 0xce, 0x84, 0xb4, 0x27, 0x55, 0x14,
	0xe3, 0x75, 0x59, 0x73, 0x71, 0x51, 0xea, 0xe8,
	0xcc, 0xda, 0x4f, 0x09, 0xaf, 0xa4, 0xbc, 0x0e,
	0xa6, 0x1f, 0xe2, 0x3a, 0xf8, 0x96, 0x7d, 0x30,
	0x23, 0xc5, 0x12, 0xb5, 0xd8, 0x73, 0x6b, 0x71,
	0xab, 0xf1, 0xd7, 0x43, 0x58, 0xa7, 0xc9, 0xf0,
	0xe4, 0x85, 0x1c, 0xd6, 0x92, 0x50, 0x2c, 0x98,
	0x36, 0xfe, 0x87, 0xaf, 0x43, 0x8f, 0x8f, 0xf5,
	0x88, 0x48, 0x18, 0x42, 0xcf, 0x42, 0xc1, 0xa8,
	0xe8, 0x05, 0x08, 0xa1, 0x45, 0x70, 0x5b, 0x8c,
	0x39, 0x28, 0xab, 0xe9, 0x6b, 0x51, 0xd2, 0xcb,
	0x30, 0x04, 0xea, 0x7d, 0x2f, 0x6e, 0x6c, 0x3b,
	0x5f, 0x82, 0xd9, 0x5b, 0x89, 0x37, 0x65, 0x65,
	0xbe, 0x9f, 0xa3, 0x5d,
	};

	string Readlink(const string& path) {
	vector<char> buf(PATH_MAX + 1);
	ssize_t r = readlink(path.c_str(), buf.data(), buf.size());
	if (r < 0)
	return "";
	CHECK_LT(r, static_cast<ssize_t>(buf.size()));
	return string(buf.begin(), buf.begin() + r);
	}

	bool IsXAttrSupported(const base::FilePath& dir_path) {
	char *path = strdup(dir_path.Append("xattr_test_XXXXXX").value().c_str());

	int fd = mkstemp(path);
	if (fd == -1) {
	PLOG(ERROR) << "Error creating temporary file in " << dir_path.value();
	free(path);
	return false;
	}

	if (unlink(path) != 0) {
	PLOG(ERROR) << "Error unlinking temporary file " << path;
	close(fd);
	free(path);
	return false;
	}

	int xattr_res = fsetxattr(fd, "user.xattr-test", "value", strlen("value"), 0);
	if (xattr_res != 0) {
	if (errno == ENOTSUP) {
	// Leave it to call-sites to warn about non-support.
	} else {
	PLOG(ERROR) << "Error setting xattr on " << path;
	}
	}
	close(fd);
	free(path);
	return xattr_res == 0;
	}

	bool WriteFileVector(const string& path, const brillo::Blob& data) {
	return utils::WriteFile(path.c_str(), data.data(), data.size());
	}

	bool WriteFileString(const string& path, const string& data) {
	return utils::WriteFile(path.c_str(), data.data(), data.size());
	}

	bool BindToUnusedLoopDevice(const string& filename,
	bool writable,
	string* out_lo_dev_name) {
	CHECK(out_lo_dev_name);
	// Get the next available loop-device.
	int control_fd =
	HANDLE_EINTR(open("/dev/loop-control", O_RDWR \| O_LARGEFILE));
	TEST_AND_RETURN_FALSE_ERRNO(control_fd >= 0);
	int loop_number = ioctl(control_fd, LOOP_CTL_GET_FREE);
	IGNORE_EINTR(close(control_fd));
	*out_lo_dev_name = StringPrintf("/dev/loop%d", loop_number);

	// Double check that the loop exists and is free.
	int loop_device_fd =
	HANDLE_EINTR(open(out_lo_dev_name->c_str(), O_RDWR \| O_LARGEFILE));
	if (loop_device_fd == -1 && errno == ENOENT) {
	// Workaround the case when the loop device doesn't exist.
	TEST_AND_RETURN_FALSE_ERRNO(mknod(out_lo_dev_name->c_str(),
	S_IFBLK \| 0660,
	makedev(LOOP_MAJOR, loop_number)) == 0);
	loop_device_fd =
	HANDLE_EINTR(open(out_lo_dev_name->c_str(), O_RDWR \| O_LARGEFILE));
	}
	TEST_AND_RETURN_FALSE_ERRNO(loop_device_fd != -1);
	ScopedFdCloser loop_device_fd_closer(&loop_device_fd);

	struct loop_info64 device_info;
	if (ioctl(loop_device_fd, LOOP_GET_STATUS64, &device_info) != -1 \|\|
	errno != ENXIO) {
	PLOG(ERROR) << "Loop device " << out_lo_dev_name->c_str()
	<< " already in use";
	return false;
	}

	// Open our data file and assign it to the loop device.
	int data_fd = open(filename.c_str(),
	(writable ? O_RDWR : O_RDONLY) \| O_LARGEFILE \| O_CLOEXEC);
	TEST_AND_RETURN_FALSE_ERRNO(data_fd >= 0);
	ScopedFdCloser data_fd_closer(&data_fd);
	TEST_AND_RETURN_FALSE_ERRNO(ioctl(loop_device_fd, LOOP_SET_FD, data_fd) == 0);

	memset(&device_info, 0, sizeof(device_info));
	device_info.lo_offset = 0;
	device_info.lo_sizelimit = 0; // 0 means whole file.
	device_info.lo_flags = (writable ? 0 : LO_FLAGS_READ_ONLY);
	device_info.lo_number = loop_number;
	strncpy(reinterpret_cast<char*>(device_info.lo_file_name),
	base::FilePath(filename).BaseName().value().c_str(),
	LO_NAME_SIZE - 1);
	device_info.lo_file_name[LO_NAME_SIZE - 1] = '\0';
	TEST_AND_RETURN_FALSE_ERRNO(
	ioctl(loop_device_fd, LOOP_SET_STATUS64, &device_info) == 0);
	return true;
	}

	bool UnbindLoopDevice(const string& lo_dev_name) {
	int loop_device_fd =
	HANDLE_EINTR(open(lo_dev_name.c_str(), O_RDWR \| O_LARGEFILE));
	if (loop_device_fd == -1 && errno == ENOENT)
	return true;
	TEST_AND_RETURN_FALSE_ERRNO(loop_device_fd != -1);
	ScopedFdCloser loop_device_fd_closer(&loop_device_fd);

	struct loop_info64 device_info;
	// Check if the device is bound before trying to unbind it.
	int get_stat_err = ioctl(loop_device_fd, LOOP_GET_STATUS64, &device_info);
	if (get_stat_err == -1 && errno == ENXIO)
	return true;

	TEST_AND_RETURN_FALSE_ERRNO(ioctl(loop_device_fd, LOOP_CLR_FD) == 0);
	return true;
	}

	bool ExpectVectorsEq(const brillo::Blob& expected,
	const brillo::Blob& actual) {
	EXPECT_EQ(expected.size(), actual.size());
	if (expected.size() != actual.size())
	return false;
	bool is_all_eq = true;
	for (unsigned int i = 0; i < expected.size(); i++) {
	EXPECT_EQ(expected[i], actual[i]) << "offset: " << i;
	is_all_eq = is_all_eq && (expected[i] == actual[i]);
	}
	return is_all_eq;
	}

	void FillWithData(brillo::Blob* buffer) {
	size_t input_counter = 0;
	for (uint8_t& b : *buffer) {
	b = kRandomString[input_counter];
	input_counter++;
	input_counter %= sizeof(kRandomString);
	}
	}

	ScopedLoopMounter::ScopedLoopMounter(const string& file_path,
	string* mnt_path,
	unsigned long flags) { // NOLINT - long
	EXPECT_TRUE(temp_dir_.CreateUniqueTempDir());
	*mnt_path = temp_dir_.path().value();

	string loop_dev;
	loop_binder_.reset(
	new ScopedLoopbackDeviceBinder(file_path, true, &loop_dev));

	EXPECT_TRUE(utils::MountFilesystem(loop_dev, *mnt_path, flags, "", ""));
	unmounter_.reset(new ScopedFilesystemUnmounter(*mnt_path));
	}

	base::FilePath GetBuildArtifactsPath() {
	base::FilePath exe_path;
	base::ReadSymbolicLink(base::FilePath("/proc/self/exe"), &exe_path);
	return exe_path.DirName();
	}

	string GetBuildArtifactsPath(const string& relative_path) {
	return GetBuildArtifactsPath().Append(relative_path).value();
	}

	} // namespace test_utils
	} // namespace chromeos_update_engine