decrypt: AOSP 10 requires the use of fscrypt
fscrypt aosp doc: https://source.android.com/security/encryption/file-based
kernel fscrypt doc: https://www.kernel.org/doc/html/v4.18/filesystems/fscrypt.html
This commit implements the ability for TWRP to use fscrypt to decrypt
files on the fscrypt implementation. It has been implemented mostly
in a new successor library to e4crypt called libtwrpfscrypt. Most of the
code was ported from AOSP vold.
Notable updates include:
- updated policy storage by libtar
- lookup of fbe policies by libtwrpfscrypt
- threaded keystore operations
Big thanks to Dees_Troy for the initial trailblazing
of encryption in TWRP.
Change-Id: I69cd2eba3693a9914e00213d4943229635d0cdae
diff --git a/crypto/fscrypt/Utils.cpp b/crypto/fscrypt/Utils.cpp
new file mode 100755
index 0000000..aa71d8f
--- /dev/null
+++ b/crypto/fscrypt/Utils.cpp
@@ -0,0 +1,989 @@
+/*
+ * Copyright (C) 2015 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 "Utils.h"
+
+#include "Process.h"
+#include "sehandle.h"
+
+#include <android-base/chrono_utils.h>
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+#include <android-base/unique_fd.h>
+#include <cutils/fs.h>
+#include <logwrap/logwrap.h>
+#include <private/android_filesystem_config.h>
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <mntent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/statvfs.h>
+#include <sys/sysmacros.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <list>
+#include <mutex>
+#include <thread>
+
+#ifndef UMOUNT_NOFOLLOW
+#define UMOUNT_NOFOLLOW 0x00000008 /* Don't follow symlink on umount */
+#endif
+
+using namespace std::chrono_literals;
+using android::base::ReadFileToString;
+using android::base::StringPrintf;
+
+namespace android {
+namespace vold {
+
+security_context_t sBlkidContext = nullptr;
+security_context_t sBlkidUntrustedContext = nullptr;
+security_context_t sFsckContext = nullptr;
+security_context_t sFsckUntrustedContext = nullptr;
+struct selabel_handle* sehandle;
+
+bool sSleepOnUnmount = true;
+
+static const char* kBlkidPath = "/system/bin/blkid";
+static const char* kKeyPath = "/data/misc/vold";
+
+static const char* kProcFilesystems = "/proc/filesystems";
+
+// Lock used to protect process-level SELinux changes from racing with each
+// other between multiple threads.
+static std::mutex kSecurityLock;
+
+status_t CreateDeviceNode(const std::string& path, dev_t dev) {
+ std::lock_guard<std::mutex> lock(kSecurityLock);
+ const char* cpath = path.c_str();
+ status_t res = 0;
+
+ char* secontext = nullptr;
+ if (sehandle) {
+ if (!selabel_lookup(sehandle, &secontext, cpath, S_IFBLK)) {
+ setfscreatecon(secontext);
+ }
+ }
+
+ mode_t mode = 0660 | S_IFBLK;
+ if (mknod(cpath, mode, dev) < 0) {
+ if (errno != EEXIST) {
+ PLOG(ERROR) << "Failed to create device node for " << major(dev) << ":" << minor(dev)
+ << " at " << path;
+ res = -errno;
+ }
+ }
+
+ if (secontext) {
+ setfscreatecon(nullptr);
+ freecon(secontext);
+ }
+
+ return res;
+}
+
+status_t DestroyDeviceNode(const std::string& path) {
+ const char* cpath = path.c_str();
+ if (TEMP_FAILURE_RETRY(unlink(cpath))) {
+ return -errno;
+ } else {
+ return OK;
+ }
+}
+
+status_t PrepareDir(const std::string& path, mode_t mode, uid_t uid, gid_t gid) {
+ std::lock_guard<std::mutex> lock(kSecurityLock);
+ const char* cpath = path.c_str();
+
+ char* secontext = nullptr;
+ if (sehandle) {
+ if (!selabel_lookup(sehandle, &secontext, cpath, S_IFDIR)) {
+ setfscreatecon(secontext);
+ }
+ }
+
+ int res = fs_prepare_dir(cpath, mode, uid, gid);
+
+ if (secontext) {
+ setfscreatecon(nullptr);
+ freecon(secontext);
+ }
+
+ if (res == 0) {
+ return OK;
+ } else {
+ return -errno;
+ }
+}
+
+status_t ForceUnmount(const std::string& path) {
+ const char* cpath = path.c_str();
+ if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
+ return OK;
+ }
+ // Apps might still be handling eject request, so wait before
+ // we start sending signals
+ if (sSleepOnUnmount) sleep(5);
+
+ KillProcessesWithOpenFiles(path, SIGINT);
+ if (sSleepOnUnmount) sleep(5);
+ if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
+ return OK;
+ }
+
+ KillProcessesWithOpenFiles(path, SIGTERM);
+ if (sSleepOnUnmount) sleep(5);
+ if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
+ return OK;
+ }
+
+ KillProcessesWithOpenFiles(path, SIGKILL);
+ if (sSleepOnUnmount) sleep(5);
+ if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
+ return OK;
+ }
+
+ return -errno;
+}
+
+status_t KillProcessesUsingPath(const std::string& path) {
+ if (KillProcessesWithOpenFiles(path, SIGINT) == 0) {
+ return OK;
+ }
+ if (sSleepOnUnmount) sleep(5);
+
+ if (KillProcessesWithOpenFiles(path, SIGTERM) == 0) {
+ return OK;
+ }
+ if (sSleepOnUnmount) sleep(5);
+
+ if (KillProcessesWithOpenFiles(path, SIGKILL) == 0) {
+ return OK;
+ }
+ if (sSleepOnUnmount) sleep(5);
+
+ // Send SIGKILL a second time to determine if we've
+ // actually killed everyone with open files
+ if (KillProcessesWithOpenFiles(path, SIGKILL) == 0) {
+ return OK;
+ }
+ PLOG(ERROR) << "Failed to kill processes using " << path;
+ return -EBUSY;
+}
+
+status_t BindMount(const std::string& source, const std::string& target) {
+ if (UnmountTree(target) < 0) {
+ return -errno;
+ }
+ if (TEMP_FAILURE_RETRY(mount(source.c_str(), target.c_str(), nullptr, MS_BIND, nullptr)) < 0) {
+ PLOG(ERROR) << "Failed to bind mount " << source << " to " << target;
+ return -errno;
+ }
+ return OK;
+}
+
+status_t Symlink(const std::string& target, const std::string& linkpath) {
+ if (Unlink(linkpath) < 0) {
+ return -errno;
+ }
+ if (TEMP_FAILURE_RETRY(symlink(target.c_str(), linkpath.c_str())) < 0) {
+ PLOG(ERROR) << "Failed to create symlink " << linkpath << " to " << target;
+ return -errno;
+ }
+ return OK;
+}
+
+status_t Unlink(const std::string& linkpath) {
+ if (TEMP_FAILURE_RETRY(unlink(linkpath.c_str())) < 0 && errno != EINVAL && errno != ENOENT) {
+ PLOG(ERROR) << "Failed to unlink " << linkpath;
+ return -errno;
+ }
+ return OK;
+}
+
+status_t CreateDir(const std::string& dir, mode_t mode) {
+ struct stat sb;
+ if (TEMP_FAILURE_RETRY(stat(dir.c_str(), &sb)) == 0) {
+ if (S_ISDIR(sb.st_mode)) {
+ return OK;
+ } else if (TEMP_FAILURE_RETRY(unlink(dir.c_str())) == -1) {
+ PLOG(ERROR) << "Failed to unlink " << dir;
+ return -errno;
+ }
+ } else if (errno != ENOENT) {
+ PLOG(ERROR) << "Failed to stat " << dir;
+ return -errno;
+ }
+ if (TEMP_FAILURE_RETRY(mkdir(dir.c_str(), mode)) == -1 && errno != EEXIST) {
+ PLOG(ERROR) << "Failed to mkdir " << dir;
+ return -errno;
+ }
+ return OK;
+}
+
+bool FindValue(const std::string& raw, const std::string& key, std::string* value) {
+ auto qual = key + "=\"";
+ size_t start = 0;
+ while (true) {
+ start = raw.find(qual, start);
+ if (start == std::string::npos) return false;
+ if (start == 0 || raw[start - 1] == ' ') {
+ break;
+ }
+ start += 1;
+ }
+ start += qual.length();
+
+ auto end = raw.find("\"", start);
+ if (end == std::string::npos) return false;
+
+ *value = raw.substr(start, end - start);
+ return true;
+}
+
+static status_t readMetadata(const std::string& path, std::string* fsType, std::string* fsUuid,
+ std::string* fsLabel, bool untrusted) {
+ fsType->clear();
+ fsUuid->clear();
+ fsLabel->clear();
+
+ std::vector<std::string> cmd;
+ cmd.push_back(kBlkidPath);
+ cmd.push_back("-c");
+ cmd.push_back("/dev/null");
+ cmd.push_back("-s");
+ cmd.push_back("TYPE");
+ cmd.push_back("-s");
+ cmd.push_back("UUID");
+ cmd.push_back("-s");
+ cmd.push_back("LABEL");
+ cmd.push_back(path);
+
+ std::vector<std::string> output;
+ status_t res = ForkExecvp(cmd, &output, untrusted ? sBlkidUntrustedContext : sBlkidContext);
+ if (res != OK) {
+ LOG(WARNING) << "blkid failed to identify " << path;
+ return res;
+ }
+
+ for (const auto& line : output) {
+ // Extract values from blkid output, if defined
+ FindValue(line, "TYPE", fsType);
+ FindValue(line, "UUID", fsUuid);
+ FindValue(line, "LABEL", fsLabel);
+ }
+
+ return OK;
+}
+
+status_t ReadMetadata(const std::string& path, std::string* fsType, std::string* fsUuid,
+ std::string* fsLabel) {
+ return readMetadata(path, fsType, fsUuid, fsLabel, false);
+}
+
+status_t ReadMetadataUntrusted(const std::string& path, std::string* fsType, std::string* fsUuid,
+ std::string* fsLabel) {
+ return readMetadata(path, fsType, fsUuid, fsLabel, true);
+}
+
+static std::vector<const char*> ConvertToArgv(const std::vector<std::string>& args) {
+ std::vector<const char*> argv;
+ argv.reserve(args.size() + 1);
+ for (const auto& arg : args) {
+ if (argv.empty()) {
+ LOG(DEBUG) << arg;
+ } else {
+ LOG(DEBUG) << " " << arg;
+ }
+ argv.emplace_back(arg.data());
+ }
+ argv.emplace_back(nullptr);
+ return argv;
+}
+
+static status_t ReadLinesFromFdAndLog(std::vector<std::string>* output,
+ android::base::unique_fd ufd) {
+ std::unique_ptr<FILE, int (*)(FILE*)> fp(android::base::Fdopen(std::move(ufd), "r"), fclose);
+ if (!fp) {
+ PLOG(ERROR) << "fdopen in ReadLinesFromFdAndLog";
+ return -errno;
+ }
+ if (output) output->clear();
+ char line[1024];
+ while (fgets(line, sizeof(line), fp.get()) != nullptr) {
+ LOG(DEBUG) << line;
+ if (output) output->emplace_back(line);
+ }
+ return OK;
+}
+
+status_t ForkExecvp(const std::vector<std::string>& args, std::vector<std::string>* output,
+ security_context_t context) {
+ auto argv = ConvertToArgv(args);
+
+ android::base::unique_fd pipe_read, pipe_write;
+ if (!android::base::Pipe(&pipe_read, &pipe_write)) {
+ PLOG(ERROR) << "Pipe in ForkExecvp";
+ return -errno;
+ }
+
+ pid_t pid = fork();
+ if (pid == 0) {
+ if (context) {
+ if (setexeccon(context)) {
+ LOG(ERROR) << "Failed to setexeccon in ForkExecvp";
+ abort();
+ }
+ }
+ pipe_read.reset();
+ if (dup2(pipe_write.get(), STDOUT_FILENO) == -1) {
+ PLOG(ERROR) << "dup2 in ForkExecvp";
+ _exit(EXIT_FAILURE);
+ }
+ pipe_write.reset();
+ execvp(argv[0], const_cast<char**>(argv.data()));
+ PLOG(ERROR) << "exec in ForkExecvp" << " cmd: " << argv[0];
+ _exit(EXIT_FAILURE);
+ }
+ if (pid == -1) {
+ PLOG(ERROR) << "fork in ForkExecvp";
+ return -errno;
+ }
+
+ pipe_write.reset();
+ auto st = ReadLinesFromFdAndLog(output, std::move(pipe_read));
+ if (st != 0) return st;
+
+ int status;
+ if (waitpid(pid, &status, 0) == -1) {
+ PLOG(ERROR) << "waitpid in ForkExecvp";
+ return -errno;
+ }
+ if (!WIFEXITED(status)) {
+ LOG(ERROR) << "Process did not exit normally, status: " << status;
+ return -ECHILD;
+ }
+ if (WEXITSTATUS(status)) {
+ LOG(ERROR) << "Process exited with code: " << WEXITSTATUS(status);
+ return WEXITSTATUS(status);
+ }
+ return OK;
+}
+
+pid_t ForkExecvpAsync(const std::vector<std::string>& args) {
+ auto argv = ConvertToArgv(args);
+
+ pid_t pid = fork();
+ if (pid == 0) {
+ close(STDIN_FILENO);
+ close(STDOUT_FILENO);
+ close(STDERR_FILENO);
+
+ execvp(argv[0], const_cast<char**>(argv.data()));
+ PLOG(ERROR) << "exec in ForkExecvpAsync";
+ _exit(EXIT_FAILURE);
+ }
+ if (pid == -1) {
+ PLOG(ERROR) << "fork in ForkExecvpAsync";
+ return -1;
+ }
+ return pid;
+}
+
+status_t ReadRandomBytes(size_t bytes, std::string& out) {
+ out.resize(bytes);
+ return ReadRandomBytes(bytes, &out[0]);
+}
+
+status_t ReadRandomBytes(size_t bytes, char* buf) {
+ int fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOFOLLOW));
+ if (fd == -1) {
+ return -errno;
+ }
+
+ ssize_t n;
+ while ((n = TEMP_FAILURE_RETRY(read(fd, &buf[0], bytes))) > 0) {
+ bytes -= n;
+ buf += n;
+ }
+ close(fd);
+
+ if (bytes == 0) {
+ return OK;
+ } else {
+ return -EIO;
+ }
+}
+
+status_t GenerateRandomUuid(std::string& out) {
+ status_t res = ReadRandomBytes(16, out);
+ if (res == OK) {
+ out[6] &= 0x0f; /* clear version */
+ out[6] |= 0x40; /* set to version 4 */
+ out[8] &= 0x3f; /* clear variant */
+ out[8] |= 0x80; /* set to IETF variant */
+ }
+ return res;
+}
+
+status_t HexToStr(const std::string& hex, std::string& str) {
+ str.clear();
+ bool even = true;
+ char cur = 0;
+ for (size_t i = 0; i < hex.size(); i++) {
+ int val = 0;
+ switch (hex[i]) {
+ // clang-format off
+ case ' ': case '-': case ':': continue;
+ case 'f': case 'F': val = 15; break;
+ case 'e': case 'E': val = 14; break;
+ case 'd': case 'D': val = 13; break;
+ case 'c': case 'C': val = 12; break;
+ case 'b': case 'B': val = 11; break;
+ case 'a': case 'A': val = 10; break;
+ case '9': val = 9; break;
+ case '8': val = 8; break;
+ case '7': val = 7; break;
+ case '6': val = 6; break;
+ case '5': val = 5; break;
+ case '4': val = 4; break;
+ case '3': val = 3; break;
+ case '2': val = 2; break;
+ case '1': val = 1; break;
+ case '0': val = 0; break;
+ default: return -EINVAL;
+ // clang-format on
+ }
+
+ if (even) {
+ cur = val << 4;
+ } else {
+ cur += val;
+ str.push_back(cur);
+ cur = 0;
+ }
+ even = !even;
+ }
+ return even ? OK : -EINVAL;
+}
+
+static const char* kLookup = "0123456789abcdef";
+
+status_t StrToHex(const std::string& str, std::string& hex) {
+ hex.clear();
+ for (size_t i = 0; i < str.size(); i++) {
+ hex.push_back(kLookup[(str[i] & 0xF0) >> 4]);
+ hex.push_back(kLookup[str[i] & 0x0F]);
+ }
+ return OK;
+}
+
+status_t StrToHex(const KeyBuffer& str, KeyBuffer& hex) {
+ hex.clear();
+ for (size_t i = 0; i < str.size(); i++) {
+ hex.push_back(kLookup[(str.data()[i] & 0xF0) >> 4]);
+ hex.push_back(kLookup[str.data()[i] & 0x0F]);
+ }
+ return OK;
+}
+
+status_t NormalizeHex(const std::string& in, std::string& out) {
+ std::string tmp;
+ if (HexToStr(in, tmp)) {
+ return -EINVAL;
+ }
+ return StrToHex(tmp, out);
+}
+
+status_t GetBlockDevSize(int fd, uint64_t* size) {
+ if (ioctl(fd, BLKGETSIZE64, size)) {
+ return -errno;
+ }
+
+ return OK;
+}
+
+status_t GetBlockDevSize(const std::string& path, uint64_t* size) {
+ int fd = open(path.c_str(), O_RDONLY | O_CLOEXEC);
+ status_t res = OK;
+
+ if (fd < 0) {
+ return -errno;
+ }
+
+ res = GetBlockDevSize(fd, size);
+
+ close(fd);
+
+ return res;
+}
+
+status_t GetBlockDev512Sectors(const std::string& path, uint64_t* nr_sec) {
+ uint64_t size;
+ status_t res = GetBlockDevSize(path, &size);
+
+ if (res != OK) {
+ return res;
+ }
+
+ *nr_sec = size / 512;
+
+ return OK;
+}
+
+uint64_t GetFreeBytes(const std::string& path) {
+ struct statvfs sb;
+ if (statvfs(path.c_str(), &sb) == 0) {
+ return (uint64_t)sb.f_bavail * sb.f_frsize;
+ } else {
+ return -1;
+ }
+}
+
+// TODO: borrowed from frameworks/native/libs/diskusage/ which should
+// eventually be migrated into system/
+static int64_t stat_size(struct stat* s) {
+ int64_t blksize = s->st_blksize;
+ // count actual blocks used instead of nominal file size
+ int64_t size = s->st_blocks * 512;
+
+ if (blksize) {
+ /* round up to filesystem block size */
+ size = (size + blksize - 1) & (~(blksize - 1));
+ }
+
+ return size;
+}
+
+// TODO: borrowed from frameworks/native/libs/diskusage/ which should
+// eventually be migrated into system/
+int64_t calculate_dir_size(int dfd) {
+ int64_t size = 0;
+ struct stat s;
+ DIR* d;
+ struct dirent* de;
+
+ d = fdopendir(dfd);
+ if (d == NULL) {
+ close(dfd);
+ return 0;
+ }
+
+ while ((de = readdir(d))) {
+ const char* name = de->d_name;
+ if (fstatat(dfd, name, &s, AT_SYMLINK_NOFOLLOW) == 0) {
+ size += stat_size(&s);
+ }
+ if (de->d_type == DT_DIR) {
+ int subfd;
+
+ /* always skip "." and ".." */
+ if (name[0] == '.') {
+ if (name[1] == 0) continue;
+ if ((name[1] == '.') && (name[2] == 0)) continue;
+ }
+
+ subfd = openat(dfd, name, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+ if (subfd >= 0) {
+ size += calculate_dir_size(subfd);
+ }
+ }
+ }
+ closedir(d);
+ return size;
+}
+
+uint64_t GetTreeBytes(const std::string& path) {
+ int dirfd = open(path.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+ if (dirfd < 0) {
+ PLOG(WARNING) << "Failed to open " << path;
+ return -1;
+ } else {
+ return calculate_dir_size(dirfd);
+ }
+}
+
+bool IsFilesystemSupported(const std::string& fsType) {
+ std::string supported;
+ if (!ReadFileToString(kProcFilesystems, &supported)) {
+ PLOG(ERROR) << "Failed to read supported filesystems";
+ return false;
+ }
+ return supported.find(fsType + "\n") != std::string::npos;
+}
+
+status_t WipeBlockDevice(const std::string& path) {
+ status_t res = -1;
+ const char* c_path = path.c_str();
+ uint64_t range[2] = {0, 0};
+
+ int fd = TEMP_FAILURE_RETRY(open(c_path, O_RDWR | O_CLOEXEC));
+ if (fd == -1) {
+ PLOG(ERROR) << "Failed to open " << path;
+ goto done;
+ }
+
+ if (GetBlockDevSize(fd, &range[1]) != OK) {
+ PLOG(ERROR) << "Failed to determine size of " << path;
+ goto done;
+ }
+
+ LOG(INFO) << "About to discard " << range[1] << " on " << path;
+ if (ioctl(fd, BLKDISCARD, &range) == 0) {
+ LOG(INFO) << "Discard success on " << path;
+ res = 0;
+ } else {
+ PLOG(ERROR) << "Discard failure on " << path;
+ }
+
+done:
+ close(fd);
+ return res;
+}
+
+static bool isValidFilename(const std::string& name) {
+ if (name.empty() || (name == ".") || (name == "..") || (name.find('/') != std::string::npos)) {
+ return false;
+ } else {
+ return true;
+ }
+}
+
+std::string BuildKeyPath(const std::string& partGuid) {
+ return StringPrintf("%s/expand_%s.key", kKeyPath, partGuid.c_str());
+}
+
+std::string BuildDataSystemLegacyPath(userid_t userId) {
+ return StringPrintf("%s/system/users/%u", BuildDataPath("").c_str(), userId);
+}
+
+std::string BuildDataSystemCePath(userid_t userId) {
+ return StringPrintf("%s/system_ce/%u", BuildDataPath("").c_str(), userId);
+}
+
+std::string BuildDataSystemDePath(userid_t userId) {
+ return StringPrintf("%s/system_de/%u", BuildDataPath("").c_str(), userId);
+}
+
+std::string BuildDataMiscLegacyPath(userid_t userId) {
+ return StringPrintf("%s/misc/user/%u", BuildDataPath("").c_str(), userId);
+}
+
+std::string BuildDataMiscCePath(userid_t userId) {
+ return StringPrintf("%s/misc_ce/%u", BuildDataPath("").c_str(), userId);
+}
+
+std::string BuildDataMiscDePath(userid_t userId) {
+ return StringPrintf("%s/misc_de/%u", BuildDataPath("").c_str(), userId);
+}
+
+// Keep in sync with installd (frameworks/native/cmds/installd/utils.h)
+std::string BuildDataProfilesDePath(userid_t userId) {
+ return StringPrintf("%s/misc/profiles/cur/%u", BuildDataPath("").c_str(), userId);
+}
+
+std::string BuildDataVendorCePath(userid_t userId) {
+ return StringPrintf("%s/vendor_ce/%u", BuildDataPath("").c_str(), userId);
+}
+
+std::string BuildDataVendorDePath(userid_t userId) {
+ return StringPrintf("%s/vendor_de/%u", BuildDataPath("").c_str(), userId);
+}
+
+std::string BuildDataPath(const std::string& volumeUuid) {
+ // TODO: unify with installd path generation logic
+ if (volumeUuid.empty()) {
+ return "/data";
+ } else {
+ CHECK(isValidFilename(volumeUuid));
+ return StringPrintf("/mnt/expand/%s", volumeUuid.c_str());
+ }
+}
+
+std::string BuildDataMediaCePath(const std::string& volumeUuid, userid_t userId) {
+ // TODO: unify with installd path generation logic
+ std::string data(BuildDataPath(volumeUuid));
+ return StringPrintf("%s/media/%u", data.c_str(), userId);
+}
+
+std::string BuildDataUserCePath(const std::string& volumeUuid, userid_t userId) {
+ // TODO: unify with installd path generation logic
+ std::string data(BuildDataPath(volumeUuid));
+ if (volumeUuid.empty() && userId == 0) {
+ std::string legacy = StringPrintf("%s/data", data.c_str());
+ struct stat sb;
+ if (lstat(legacy.c_str(), &sb) == 0 && S_ISDIR(sb.st_mode)) {
+ /* /data/data is dir, return /data/data for legacy system */
+ return legacy;
+ }
+ }
+ return StringPrintf("%s/user/%u", data.c_str(), userId);
+}
+
+std::string BuildDataUserDePath(const std::string& volumeUuid, userid_t userId) {
+ // TODO: unify with installd path generation logic
+ std::string data(BuildDataPath(volumeUuid));
+ return StringPrintf("%s/user_de/%u", data.c_str(), userId);
+}
+
+dev_t GetDevice(const std::string& path) {
+ struct stat sb;
+ if (stat(path.c_str(), &sb)) {
+ PLOG(WARNING) << "Failed to stat " << path;
+ return 0;
+ } else {
+ return sb.st_dev;
+ }
+}
+
+status_t RestoreconRecursive(const std::string& path) {
+ LOG(DEBUG) << "Starting restorecon of " << path;
+
+ static constexpr const char* kRestoreconString = "selinux.restorecon_recursive";
+
+ android::base::SetProperty(kRestoreconString, "");
+ android::base::SetProperty(kRestoreconString, path);
+
+ android::base::WaitForProperty(kRestoreconString, path);
+
+ LOG(DEBUG) << "Finished restorecon of " << path;
+ return OK;
+}
+
+bool Readlinkat(int dirfd, const std::string& path, std::string* result) {
+ // Shamelessly borrowed from android::base::Readlink()
+ result->clear();
+
+ // Most Linux file systems (ext2 and ext4, say) limit symbolic links to
+ // 4095 bytes. Since we'll copy out into the string anyway, it doesn't
+ // waste memory to just start there. We add 1 so that we can recognize
+ // whether it actually fit (rather than being truncated to 4095).
+ std::vector<char> buf(4095 + 1);
+ while (true) {
+ ssize_t size = readlinkat(dirfd, path.c_str(), &buf[0], buf.size());
+ // Unrecoverable error?
+ if (size == -1) return false;
+ // It fit! (If size == buf.size(), it may have been truncated.)
+ if (static_cast<size_t>(size) < buf.size()) {
+ result->assign(&buf[0], size);
+ return true;
+ }
+ // Double our buffer and try again.
+ buf.resize(buf.size() * 2);
+ }
+}
+
+bool IsRunningInEmulator() {
+ return android::base::GetBoolProperty("ro.kernel.qemu", false);
+}
+
+static status_t findMountPointsWithPrefix(const std::string& prefix,
+ std::list<std::string>& mountPoints) {
+ // Add a trailing slash if the client didn't provide one so that we don't match /foo/barbaz
+ // when the prefix is /foo/bar
+ std::string prefixWithSlash(prefix);
+ if (prefix.back() != '/') {
+ android::base::StringAppendF(&prefixWithSlash, "/");
+ }
+
+ std::unique_ptr<FILE, int (*)(FILE*)> mnts(setmntent("/proc/mounts", "re"), endmntent);
+ if (!mnts) {
+ PLOG(ERROR) << "Unable to open /proc/mounts";
+ return -errno;
+ }
+
+ // Some volumes can be stacked on each other, so force unmount in
+ // reverse order to give us the best chance of success.
+ struct mntent* mnt; // getmntent returns a thread local, so it's safe.
+ while ((mnt = getmntent(mnts.get())) != nullptr) {
+ auto mountPoint = std::string(mnt->mnt_dir) + "/";
+ if (android::base::StartsWith(mountPoint, prefixWithSlash)) {
+ mountPoints.push_front(mountPoint);
+ }
+ }
+ return OK;
+}
+
+// Unmount all mountpoints that start with prefix. prefix itself doesn't need to be a mountpoint.
+status_t UnmountTreeWithPrefix(const std::string& prefix) {
+ std::list<std::string> toUnmount;
+ status_t result = findMountPointsWithPrefix(prefix, toUnmount);
+ if (result < 0) {
+ return result;
+ }
+ for (const auto& path : toUnmount) {
+ if (umount2(path.c_str(), MNT_DETACH)) {
+ PLOG(ERROR) << "Failed to unmount " << path;
+ result = -errno;
+ }
+ }
+ return result;
+}
+
+status_t UnmountTree(const std::string& mountPoint) {
+ if (TEMP_FAILURE_RETRY(umount2(mountPoint.c_str(), MNT_DETACH)) < 0 && errno != EINVAL &&
+ errno != ENOENT) {
+ PLOG(ERROR) << "Failed to unmount " << mountPoint;
+ return -errno;
+ }
+ return OK;
+}
+
+static status_t delete_dir_contents(DIR* dir) {
+ // Shamelessly borrowed from android::installd
+ int dfd = dirfd(dir);
+ if (dfd < 0) {
+ return -errno;
+ }
+
+ status_t result = OK;
+ struct dirent* de;
+ while ((de = readdir(dir))) {
+ const char* name = de->d_name;
+ if (de->d_type == DT_DIR) {
+ /* always skip "." and ".." */
+ if (name[0] == '.') {
+ if (name[1] == 0) continue;
+ if ((name[1] == '.') && (name[2] == 0)) continue;
+ }
+
+ android::base::unique_fd subfd(
+ openat(dfd, name, O_RDONLY | O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC));
+ if (subfd.get() == -1) {
+ PLOG(ERROR) << "Couldn't openat " << name;
+ result = -errno;
+ continue;
+ }
+ std::unique_ptr<DIR, decltype(&closedir)> subdirp(
+ android::base::Fdopendir(std::move(subfd)), closedir);
+ if (!subdirp) {
+ PLOG(ERROR) << "Couldn't fdopendir " << name;
+ result = -errno;
+ continue;
+ }
+ result = delete_dir_contents(subdirp.get());
+ if (unlinkat(dfd, name, AT_REMOVEDIR) < 0) {
+ PLOG(ERROR) << "Couldn't unlinkat " << name;
+ result = -errno;
+ }
+ } else {
+ if (unlinkat(dfd, name, 0) < 0) {
+ PLOG(ERROR) << "Couldn't unlinkat " << name;
+ result = -errno;
+ }
+ }
+ }
+ return result;
+}
+
+status_t DeleteDirContentsAndDir(const std::string& pathname) {
+ status_t res = DeleteDirContents(pathname);
+ if (res < 0) {
+ return res;
+ }
+ if (TEMP_FAILURE_RETRY(rmdir(pathname.c_str())) < 0 && errno != ENOENT) {
+ PLOG(ERROR) << "rmdir failed on " << pathname;
+ return -errno;
+ }
+ LOG(VERBOSE) << "Success: rmdir on " << pathname;
+ return OK;
+}
+
+status_t DeleteDirContents(const std::string& pathname) {
+ // Shamelessly borrowed from android::installd
+ std::unique_ptr<DIR, decltype(&closedir)> dirp(opendir(pathname.c_str()), closedir);
+ if (!dirp) {
+ if (errno == ENOENT) {
+ return OK;
+ }
+ PLOG(ERROR) << "Failed to opendir " << pathname;
+ return -errno;
+ }
+ return delete_dir_contents(dirp.get());
+}
+
+// TODO(118708649): fix duplication with init/util.h
+status_t WaitForFile(const char* filename, std::chrono::nanoseconds timeout) {
+ android::base::Timer t;
+ while (t.duration() < timeout) {
+ struct stat sb;
+ if (stat(filename, &sb) != -1) {
+ LOG(INFO) << "wait for '" << filename << "' took " << t;
+ return 0;
+ }
+ std::this_thread::sleep_for(10ms);
+ }
+ LOG(WARNING) << "wait for '" << filename << "' timed out and took " << t;
+ return -1;
+}
+
+bool FsyncDirectory(const std::string& dirname) {
+ android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(dirname.c_str(), O_RDONLY | O_CLOEXEC)));
+ if (fd == -1) {
+ PLOG(ERROR) << "Failed to open " << dirname;
+ return false;
+ }
+ if (fsync(fd) == -1) {
+ if (errno == EROFS || errno == EINVAL) {
+ PLOG(WARNING) << "Skip fsync " << dirname
+ << " on a file system does not support synchronization";
+ } else {
+ PLOG(ERROR) << "Failed to fsync " << dirname;
+ return false;
+ }
+ }
+ return true;
+}
+
+bool writeStringToFile(const std::string& payload, const std::string& filename) {
+ android::base::unique_fd fd(TEMP_FAILURE_RETRY(
+ open(filename.c_str(), O_WRONLY | O_CREAT | O_NOFOLLOW | O_TRUNC | O_CLOEXEC, 0666)));
+ if (fd == -1) {
+ PLOG(ERROR) << "Failed to open " << filename;
+ return false;
+ }
+ if (!android::base::WriteStringToFd(payload, fd)) {
+ PLOG(ERROR) << "Failed to write to " << filename;
+ unlink(filename.c_str());
+ return false;
+ }
+ // fsync as close won't guarantee flush data
+ // see close(2), fsync(2) and b/68901441
+ if (fsync(fd) == -1) {
+ if (errno == EROFS || errno == EINVAL) {
+ PLOG(WARNING) << "Skip fsync " << filename
+ << " on a file system does not support synchronization";
+ } else {
+ PLOG(ERROR) << "Failed to fsync " << filename;
+ unlink(filename.c_str());
+ return false;
+ }
+ }
+ return true;
+}
+
+} // namespace vold
+} // namespace android