xref: /frameworks/base/core/jni/com_android_internal_os_Zygote.cpp

/*
 * Copyright (C) 2008 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.
 */

#define LOG_TAG "Zygote"
#define ATRACE_TAG ATRACE_TAG_DALVIK

#include "com_android_internal_os_Zygote.h"

#include <async_safe/log.h>

// sys/mount.h has to come before linux/fs.h due to redefinition of MS_RDONLY, MS_BIND, etc
#include <sys/mount.h>
#include <linux/fs.h>
#include <sys/types.h>
#include <dirent.h>

#include <algorithm>
#include <array>
#include <atomic>
#include <functional>
#include <iterator>
#include <list>
#include <optional>
#include <sstream>
#include <string>
#include <string_view>
#include <unordered_set>

#include <android/fdsan.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <grp.h>
#include <inttypes.h>
#include <malloc.h>
#include <mntent.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/auxv.h>
#include <sys/capability.h>
#include <sys/cdefs.h>
#include <sys/eventfd.h>
#include <sys/personality.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>

#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/unique_fd.h>
#include <bionic/malloc.h>
#include <bionic/mte.h>
#include <cutils/fs.h>
#include <cutils/multiuser.h>
#include <cutils/sockets.h>
#include <private/android_filesystem_config.h>
#include <processgroup/processgroup.h>
#include <processgroup/sched_policy.h>
#include <seccomp_policy.h>
#include <selinux/android.h>
#include <stats_socket.h>
#include <utils/String8.h>
#include <utils/Trace.h>

#include <nativehelper/JNIHelp.h>
#include <nativehelper/ScopedLocalRef.h>
#include <nativehelper/ScopedPrimitiveArray.h>
#include <nativehelper/ScopedUtfChars.h>
#include "core_jni_helpers.h"
#include "fd_utils.h"
#include "filesystem_utils.h"

#include "nativebridge/native_bridge.h"

namespace {

// TODO (chriswailes): Add a function to initialize native Zygote data.
// TODO (chriswailes): Fix mixed indentation style (2 and 4 spaces).

using namespace std::placeholders;

using android::String8;
using android::base::ReadFileToString;
using android::base::StringAppendF;
using android::base::StringPrintf;
using android::base::WriteStringToFile;
using android::base::GetBoolProperty;

using android::zygote::ZygoteFailure;

using Action = android_mallopt_gwp_asan_options_t::Action;

// This type is duplicated in fd_utils.h
typedef const std::function<void(std::string)>& fail_fn_t;

static pid_t gSystemServerPid = 0;

static constexpr const char* kVoldAppDataIsolation = "persist.sys.vold_app_data_isolation_enabled";
static const char kZygoteClassName[] = "com/android/internal/os/Zygote";
static jclass gZygoteClass;
static jmethodID gCallPostForkSystemServerHooks;
static jmethodID gCallPostForkChildHooks;

static constexpr const char* kZygoteInitClassName = "com/android/internal/os/ZygoteInit";
static jclass gZygoteInitClass;
static jmethodID gGetOrCreateSystemServerClassLoader;
static jmethodID gPrefetchStandaloneSystemServerJars;

static bool gIsSecurityEnforced = true;

/**
 * True if the app process is running in its mount namespace.
 */
static bool gInAppMountNamespace = false;

/**
 * The maximum number of characters (not including a null terminator) that a
 * process name may contain.
 */
static constexpr size_t MAX_NAME_LENGTH = 15;

/**
 * The file descriptor for the Zygote socket opened by init.
 */

static int gZygoteSocketFD = -1;

/**
 * The file descriptor for the unspecialized app process (USAP) pool socket opened by init.
 */

static int gUsapPoolSocketFD = -1;

/**
 * The number of USAPs currently in this Zygote's pool.
 */
static std::atomic_uint32_t gUsapPoolCount = 0;

/**
 * Event file descriptor used to communicate reaped USAPs to the
 * ZygoteServer.
 */
static int gUsapPoolEventFD = -1;

/**
 * The socket file descriptor used to send notifications to the
 * system_server.
 */
static int gSystemServerSocketFd = -1;

static constexpr int DEFAULT_DATA_DIR_PERMISSION = 0751;

static constexpr const uint64_t UPPER_HALF_WORD_MASK = 0xFFFF'FFFF'0000'0000;
static constexpr const uint64_t LOWER_HALF_WORD_MASK = 0x0000'0000'FFFF'FFFF;

static constexpr const char* kCurProfileDirPath = "/data/misc/profiles/cur";
static constexpr const char* kRefProfileDirPath = "/data/misc/profiles/ref";

/**
 * The maximum value that the gUSAPPoolSizeMax variable may take.  This value
 * is a mirror of ZygoteServer.USAP_POOL_SIZE_MAX_LIMIT
 */
static constexpr int USAP_POOL_SIZE_MAX_LIMIT = 100;

/** The numeric value for the maximum priority a process may possess. */
static constexpr int PROCESS_PRIORITY_MAX = -20;

/** The numeric value for the minimum priority a process may possess. */
static constexpr int PROCESS_PRIORITY_MIN = 19;

/** The numeric value for the normal priority a process should have. */
static constexpr int PROCESS_PRIORITY_DEFAULT = 0;

/** Exponential back off parameters for storage dir check. */
static constexpr unsigned int STORAGE_DIR_CHECK_RETRY_MULTIPLIER = 2;
static constexpr unsigned int STORAGE_DIR_CHECK_INIT_INTERVAL_US = 50;
static constexpr unsigned int STORAGE_DIR_CHECK_MAX_INTERVAL_US = 1000;
/**
 * Lower bound time we allow storage dir check to sleep.
 * If it exceeds 2s, PROC_START_TIMEOUT_MSG will kill the starting app anyway,
 * so it's fine to assume max retries is 5 mins.
 */
static constexpr int STORAGE_DIR_CHECK_TIMEOUT_US = 1000 * 1000 * 60 * 5;

static void WaitUntilDirReady(const std::string& target, fail_fn_t fail_fn);

/**
 * A helper class containing accounting information for USAPs.
 */
class UsapTableEntry {
 public:
  struct EntryStorage {
    int32_t pid;
    int32_t read_pipe_fd;

    bool operator!=(const EntryStorage& other) {
      return pid != other.pid || read_pipe_fd != other.read_pipe_fd;
    }
  };

 private:
  static constexpr EntryStorage INVALID_ENTRY_VALUE = {-1, -1};

  std::atomic<EntryStorage> mStorage;
  static_assert(decltype(mStorage)::is_always_lock_free);  // Accessed from signal handler.

 public:
  constexpr UsapTableEntry() : mStorage(INVALID_ENTRY_VALUE) {}

  /**
   * If the provided PID matches the one stored in this entry, the entry will
   * be invalidated and the associated file descriptor will be closed.  If the
   * PIDs don't match nothing will happen.
   *
   * @param pid The ID of the process who's entry we want to clear.
   * @return True if the entry was cleared by this call; false otherwise
   */
  bool ClearForPID(int32_t pid) {
    EntryStorage storage = mStorage.load();

    if (storage.pid == pid) {
      /*
       * There are three possible outcomes from this compare-and-exchange:
       *   1) It succeeds, in which case we close the FD
       *   2) It fails and the new value is INVALID_ENTRY_VALUE, in which case
       *      the entry has already been cleared.
       *   3) It fails and the new value isn't INVALID_ENTRY_VALUE, in which
       *      case the entry has already been cleared and re-used.
       *
       * In all three cases the goal of the caller has been met, but only in
       * the first case do we need to decrement the pool count.
       */
      if (mStorage.compare_exchange_strong(storage, INVALID_ENTRY_VALUE)) {
        close(storage.read_pipe_fd);
        return true;
      } else {
        return false;
      }

    } else {
      return false;
    }
  }

  void Clear() {
    EntryStorage storage = mStorage.load();

    if (storage != INVALID_ENTRY_VALUE) {
      close(storage.read_pipe_fd);
      mStorage.store(INVALID_ENTRY_VALUE);
    }
  }

  void Invalidate() {
    mStorage.store(INVALID_ENTRY_VALUE);
  }

  /**
   * @return A copy of the data stored in this entry.
   */
  std::optional<EntryStorage> GetValues() {
    EntryStorage storage = mStorage.load();

    if (storage != INVALID_ENTRY_VALUE) {
      return storage;
    } else {
      return std::nullopt;
    }
  }

  /**
   * Sets the entry to the given values if it is currently invalid.
   *
   * @param pid  The process ID for the new entry.
   * @param read_pipe_fd  The read end of the USAP control pipe for this
   * process.
   * @return True if the entry was set; false otherwise.
   */
  bool SetIfInvalid(int32_t pid, int32_t read_pipe_fd) {
    EntryStorage new_value_storage;

    new_value_storage.pid = pid;
    new_value_storage.read_pipe_fd = read_pipe_fd;

    EntryStorage expected = INVALID_ENTRY_VALUE;

    return mStorage.compare_exchange_strong(expected, new_value_storage);
  }
};

/**
 * A table containing information about the USAPs currently in the pool.
 *
 * Multiple threads may be attempting to modify the table, either from the
 * signal handler or from the ZygoteServer poll loop.  Atomic loads/stores in
 * the USAPTableEntry class prevent data races during these concurrent
 * operations.
 */
static std::array<UsapTableEntry, USAP_POOL_SIZE_MAX_LIMIT> gUsapTable;

/**
 * The list of open zygote file descriptors.
 */
static FileDescriptorTable* gOpenFdTable = nullptr;

// Must match values in com.android.internal.os.Zygote.
// The values should be consistent with IVold.aidl
enum MountExternalKind {
    MOUNT_EXTERNAL_NONE = 0,
    MOUNT_EXTERNAL_DEFAULT = 1,
    MOUNT_EXTERNAL_INSTALLER = 2,
    MOUNT_EXTERNAL_PASS_THROUGH = 3,
    MOUNT_EXTERNAL_ANDROID_WRITABLE = 4,
    MOUNT_EXTERNAL_COUNT = 5
};

// Must match values in com.android.internal.os.Zygote.
enum RuntimeFlags : uint32_t {
    DEBUG_ENABLE_JDWP = 1,
    PROFILE_FROM_SHELL = 1 << 15,
    MEMORY_TAG_LEVEL_MASK = (1 << 19) | (1 << 20),
    MEMORY_TAG_LEVEL_TBI = 1 << 19,
    MEMORY_TAG_LEVEL_ASYNC = 2 << 19,
    MEMORY_TAG_LEVEL_SYNC = 3 << 19,
    GWP_ASAN_LEVEL_MASK = (1 << 21) | (1 << 22),
    GWP_ASAN_LEVEL_NEVER = 0 << 21,
    GWP_ASAN_LEVEL_LOTTERY = 1 << 21,
    GWP_ASAN_LEVEL_ALWAYS = 2 << 21,
    NATIVE_HEAP_ZERO_INIT_ENABLED = 1 << 23,
    PROFILEABLE = 1 << 24,
};

enum UnsolicitedZygoteMessageTypes : uint32_t {
    UNSOLICITED_ZYGOTE_MESSAGE_TYPE_RESERVED = 0,
    UNSOLICITED_ZYGOTE_MESSAGE_TYPE_SIGCHLD = 1,
};

struct UnsolicitedZygoteMessageSigChld {
    struct {
        UnsolicitedZygoteMessageTypes type;
    } header;
    struct {
        pid_t pid;
        uid_t uid;
        int status;
    } payload;
};

// Keep sync with services/core/java/com/android/server/am/ProcessList.java
static constexpr struct sockaddr_un kSystemServerSockAddr =
        {.sun_family = AF_LOCAL, .sun_path = "/data/system/unsolzygotesocket"};

// Forward declaration so we don't have to move the signal handler.
static bool RemoveUsapTableEntry(pid_t usap_pid);

static void RuntimeAbort(JNIEnv* env, int line, const char* msg) {
  std::ostringstream oss;
  oss << __FILE__ << ":" << line << ": " << msg;
  env->FatalError(oss.str().c_str());
}

// Create the socket which is going to be used to send unsolicited message
// to system_server, the socket will be closed post forking a child process.
// It's expected to be called at each zygote's initialization.
static void initUnsolSocketToSystemServer() {
    gSystemServerSocketFd = socket(AF_LOCAL, SOCK_DGRAM | SOCK_NONBLOCK, 0);
    if (gSystemServerSocketFd >= 0) {
        ALOGV("Zygote:systemServerSocketFD = %d", gSystemServerSocketFd);
    } else {
        ALOGE("Unable to create socket file descriptor to connect to system_server");
    }
}

static void sendSigChildStatus(const pid_t pid, const uid_t uid, const int status) {
    int socketFd = gSystemServerSocketFd;
    if (socketFd >= 0) {
        // fill the message buffer
        struct UnsolicitedZygoteMessageSigChld data =
                {.header = {.type = UNSOLICITED_ZYGOTE_MESSAGE_TYPE_SIGCHLD},
                 .payload = {.pid = pid, .uid = uid, .status = status}};
        if (TEMP_FAILURE_RETRY(
                    sendto(socketFd, &data, sizeof(data), 0,
                           reinterpret_cast<const struct sockaddr*>(&kSystemServerSockAddr),
                           sizeof(kSystemServerSockAddr))) == -1) {
            async_safe_format_log(ANDROID_LOG_ERROR, LOG_TAG,
                                  "Zygote failed to write to system_server FD: %s",
                                  strerror(errno));
        }
    }
}

// This signal handler is for zygote mode, since the zygote must reap its children
static void SigChldHandler(int /*signal_number*/, siginfo_t* info, void* /*ucontext*/) {
    pid_t pid;
    int status;
    int64_t usaps_removed = 0;

    // It's necessary to save and restore the errno during this function.
    // Since errno is stored per thread, changing it here modifies the errno
    // on the thread on which this signal handler executes. If a signal occurs
    // between a call and an errno check, it's possible to get the errno set
    // here.
    // See b/23572286 for extra information.
    int saved_errno = errno;

    while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
        // Notify system_server that we received a SIGCHLD
        sendSigChildStatus(pid, info->si_uid, status);
        // Log process-death status that we care about.
        if (WIFEXITED(status)) {
            async_safe_format_log(ANDROID_LOG_INFO, LOG_TAG, "Process %d exited cleanly (%d)", pid,
                                  WEXITSTATUS(status));

            // Check to see if the PID is in the USAP pool and remove it if it is.
            if (RemoveUsapTableEntry(pid)) {
                ++usaps_removed;
            }
        } else if (WIFSIGNALED(status)) {
            async_safe_format_log(ANDROID_LOG_INFO, LOG_TAG,
                                  "Process %d exited due to signal %d (%s)%s", pid,
                                  WTERMSIG(status), strsignal(WTERMSIG(status)),
                                  WCOREDUMP(status) ? "; core dumped" : "");

            // If the process exited due to a signal other than SIGTERM, check to see
            // if the PID is in the USAP pool and remove it if it is.  If the process
            // was closed by the Zygote using SIGTERM then the USAP pool entry will
            // have already been removed (see nativeEmptyUsapPool()).
            if (WTERMSIG(status) != SIGTERM && RemoveUsapTableEntry(pid)) {
                ++usaps_removed;
            }
        }

        // If the just-crashed process is the system_server, bring down zygote
        // so that it is restarted by init and system server will be restarted
        // from there.
        if (pid == gSystemServerPid) {
            async_safe_format_log(ANDROID_LOG_ERROR, LOG_TAG,
                                  "Exit zygote because system server (pid %d) has terminated", pid);
            kill(getpid(), SIGKILL);
        }
    }

    // Note that we shouldn't consider ECHILD an error because
    // the secondary zygote might have no children left to wait for.
    if (pid < 0 && errno != ECHILD) {
        async_safe_format_log(ANDROID_LOG_WARN, LOG_TAG, "Zygote SIGCHLD error in waitpid: %s",
                              strerror(errno));
    }

    if (usaps_removed > 0) {
        if (TEMP_FAILURE_RETRY(write(gUsapPoolEventFD, &usaps_removed, sizeof(usaps_removed))) ==
            -1) {
            // If this write fails something went terribly wrong.  We will now kill
            // the zygote and let the system bring it back up.
            async_safe_format_log(ANDROID_LOG_ERROR, LOG_TAG,
                                  "Zygote failed to write to USAP pool event FD: %s",
                                  strerror(errno));
            kill(getpid(), SIGKILL);
        }
    }

    errno = saved_errno;
}

// Configures the SIGCHLD/SIGHUP handlers for the zygote process. This is
// configured very late, because earlier in the runtime we may fork() and
// exec() other processes, and we want to waitpid() for those rather than
// have them be harvested immediately.
//
// Ignore SIGHUP because all processes forked by the zygote are in the same
// process group as the zygote and we don't want to be notified if we become
// an orphaned group and have one or more stopped processes. This is not a
// theoretical concern :
// - we can become an orphaned group if one of our direct descendants forks
//   and is subsequently killed before its children.
// - crash_dump routinely STOPs the process it's tracing.
//
// See issues b/71965619 and b/25567761 for further details.
//
// This ends up being called repeatedly before each fork(), but there's
// no real harm in that.
static void SetSignalHandlers() {
    struct sigaction sig_chld = {.sa_flags = SA_SIGINFO, .sa_sigaction = SigChldHandler};

    if (sigaction(SIGCHLD, &sig_chld, nullptr) < 0) {
        ALOGW("Error setting SIGCHLD handler: %s", strerror(errno));
    }

  struct sigaction sig_hup = {};
  sig_hup.sa_handler = SIG_IGN;
  if (sigaction(SIGHUP, &sig_hup, nullptr) < 0) {
    ALOGW("Error setting SIGHUP handler: %s", strerror(errno));
  }
}

// Sets the SIGCHLD handler back to default behavior in zygote children.
static void UnsetChldSignalHandler() {
  struct sigaction sa;
  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = SIG_DFL;

  if (sigaction(SIGCHLD, &sa, nullptr) < 0) {
    ALOGW("Error unsetting SIGCHLD handler: %s", strerror(errno));
  }
}

// Calls POSIX setgroups() using the int[] object as an argument.
// A nullptr argument is tolerated.
static void SetGids(JNIEnv* env, jintArray managed_gids, jboolean is_child_zygote,
                    fail_fn_t fail_fn) {
  if (managed_gids == nullptr) {
    if (is_child_zygote) {
      // For child zygotes like webview and app zygote, we want to clear out
      // any supplemental groups the parent zygote had.
      if (setgroups(0, NULL) == -1) {
        fail_fn(CREATE_ERROR("Failed to remove supplementary groups for child zygote"));
      }
    }
    return;
  }

  ScopedIntArrayRO gids(env, managed_gids);
  if (gids.get() == nullptr) {
    fail_fn(CREATE_ERROR("Getting gids int array failed"));
  }

  if (setgroups(gids.size(), reinterpret_cast<const gid_t*>(&gids[0])) == -1) {
    fail_fn(CREATE_ERROR("setgroups failed: %s, gids.size=%zu", strerror(errno), gids.size()));
  }
}

static void ensureInAppMountNamespace(fail_fn_t fail_fn) {
  if (gInAppMountNamespace) {
    // In app mount namespace already
    return;
  }
  if (unshare(CLONE_NEWNS) == -1) {
    fail_fn(CREATE_ERROR("Failed to unshare(): %s", strerror(errno)));
  }
  gInAppMountNamespace = true;
}

// Sets the resource limits via setrlimit(2) for the values in the
// two-dimensional array of integers that's passed in. The second dimension
// contains a tuple of length 3: (resource, rlim_cur, rlim_max). nullptr is
// treated as an empty array.
static void SetRLimits(JNIEnv* env, jobjectArray managed_rlimits, fail_fn_t fail_fn) {
  if (managed_rlimits == nullptr) {
    return;
  }

  rlimit rlim;
  memset(&rlim, 0, sizeof(rlim));

  for (int i = 0; i < env->GetArrayLength(managed_rlimits); ++i) {
    ScopedLocalRef<jobject>
        managed_rlimit_object(env, env->GetObjectArrayElement(managed_rlimits, i));
    ScopedIntArrayRO rlimit_handle(env, reinterpret_cast<jintArray>(managed_rlimit_object.get()));

    if (rlimit_handle.size() != 3) {
      fail_fn(CREATE_ERROR("rlimits array must have a second dimension of size 3"));
    }

    rlim.rlim_cur = rlimit_handle[1];
    rlim.rlim_max = rlimit_handle[2];

    if (setrlimit(rlimit_handle[0], &rlim) == -1) {
      fail_fn(CREATE_ERROR("setrlimit(%d, {%ld, %ld}) failed",
                           rlimit_handle[0], rlim.rlim_cur, rlim.rlim_max));
    }
  }
}

static void EnableDebugger() {
  // To let a non-privileged gdbserver attach to this
  // process, we must set our dumpable flag.
  if (prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) == -1) {
    ALOGE("prctl(PR_SET_DUMPABLE) failed");
  }

  // A non-privileged native debugger should be able to attach to the debuggable app, even if Yama
  // is enabled (see kernel/Documentation/security/Yama.txt).
  if (prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY, 0, 0, 0) == -1) {
    // if Yama is off prctl(PR_SET_PTRACER) returns EINVAL - don't log in this
    // case since it's expected behaviour.
    if (errno != EINVAL) {
      ALOGE("prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY) failed");
    }
  }

  // Set the core dump size to zero unless wanted (see also coredump_setup in build/envsetup.sh).
  if (!GetBoolProperty("persist.zygote.core_dump", false)) {
    // Set the soft limit on core dump size to 0 without changing the hard limit.
    rlimit rl;
    if (getrlimit(RLIMIT_CORE, &rl) == -1) {
      ALOGE("getrlimit(RLIMIT_CORE) failed");
    } else {
      rl.rlim_cur = 0;
      if (setrlimit(RLIMIT_CORE, &rl) == -1) {
        ALOGE("setrlimit(RLIMIT_CORE) failed");
      }
    }
  }
}

static void PreApplicationInit() {
  // The child process sets this to indicate it's not the zygote.
  android_mallopt(M_SET_ZYGOTE_CHILD, nullptr, 0);

  // Set the jemalloc decay time to 1.
  mallopt(M_DECAY_TIME, 1);
}

static void SetUpSeccompFilter(uid_t uid, bool is_child_zygote) {
  if (!gIsSecurityEnforced) {
    ALOGI("seccomp disabled by setenforce 0");
    return;
  }

  // Apply system or app filter based on uid.
  if (uid >= AID_APP_START) {
    if (is_child_zygote) {
      set_app_zygote_seccomp_filter();
    } else {
      set_app_seccomp_filter();
    }
  } else {
    set_system_seccomp_filter();
  }
}

static void EnableKeepCapabilities(fail_fn_t fail_fn) {
  if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == -1) {
    fail_fn(CREATE_ERROR("prctl(PR_SET_KEEPCAPS) failed: %s", strerror(errno)));
  }
}

static void DropCapabilitiesBoundingSet(fail_fn_t fail_fn) {
  for (int i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >= 0; i++) {;
    if (prctl(PR_CAPBSET_DROP, i, 0, 0, 0) == -1) {
      if (errno == EINVAL) {
        ALOGE("prctl(PR_CAPBSET_DROP) failed with EINVAL. Please verify "
              "your kernel is compiled with file capabilities support");
      } else {
        fail_fn(CREATE_ERROR("prctl(PR_CAPBSET_DROP, %d) failed: %s", i, strerror(errno)));
      }
    }
  }
}

static void SetInheritable(uint64_t inheritable, fail_fn_t fail_fn) {
  __user_cap_header_struct capheader;
  memset(&capheader, 0, sizeof(capheader));
  capheader.version = _LINUX_CAPABILITY_VERSION_3;
  capheader.pid = 0;

  __user_cap_data_struct capdata[2];
  if (capget(&capheader, &capdata[0]) == -1) {
    fail_fn(CREATE_ERROR("capget failed: %s", strerror(errno)));
  }

  capdata[0].inheritable = inheritable;
  capdata[1].inheritable = inheritable >> 32;

  if (capset(&capheader, &capdata[0]) == -1) {
    fail_fn(CREATE_ERROR("capset(inh=%" PRIx64 ") failed: %s", inheritable, strerror(errno)));
  }
}

static void SetCapabilities(uint64_t permitted, uint64_t effective, uint64_t inheritable,
                            fail_fn_t fail_fn) {
  __user_cap_header_struct capheader;
  memset(&capheader, 0, sizeof(capheader));
  capheader.version = _LINUX_CAPABILITY_VERSION_3;
  capheader.pid = 0;

  __user_cap_data_struct capdata[2];
  memset(&capdata, 0, sizeof(capdata));
  capdata[0].effective = effective;
  capdata[1].effective = effective >> 32;
  capdata[0].permitted = permitted;
  capdata[1].permitted = permitted >> 32;
  capdata[0].inheritable = inheritable;
  capdata[1].inheritable = inheritable >> 32;

  if (capset(&capheader, &capdata[0]) == -1) {
    fail_fn(CREATE_ERROR("capset(perm=%" PRIx64 ", eff=%" PRIx64 ", inh=%" PRIx64 ") "
                         "failed: %s", permitted, effective, inheritable, strerror(errno)));
  }
}

static void SetSchedulerPolicy(fail_fn_t fail_fn, bool is_top_app) {
  SchedPolicy policy = is_top_app ? SP_TOP_APP : SP_DEFAULT;

  if (is_top_app && cpusets_enabled()) {
    errno = -set_cpuset_policy(0, policy);
    if (errno != 0) {
      fail_fn(CREATE_ERROR("set_cpuset_policy(0, %d) failed: %s", policy, strerror(errno)));
    }
  }

  errno = -set_sched_policy(0, policy);
  if (errno != 0) {
    fail_fn(CREATE_ERROR("set_sched_policy(0, %d) failed: %s", policy, strerror(errno)));
  }

  // We are going to lose the permission to set scheduler policy during the specialization, so make
  // sure that we don't cache the fd of cgroup path that may cause sepolicy violation by writing
  // value to the cached fd directly when creating new thread.
  DropTaskProfilesResourceCaching();
}

static int UnmountTree(const char* path) {
  ATRACE_CALL();

  size_t path_len = strlen(path);

  FILE* fp = setmntent("/proc/mounts", "r");
  if (fp == nullptr) {
    ALOGE("Error opening /proc/mounts: %s", strerror(errno));
    return -errno;
  }

  // Some volumes can be stacked on each other, so force unmount in
  // reverse order to give us the best chance of success.
  std::list<std::string> to_unmount;
  mntent* mentry;
  while ((mentry = getmntent(fp)) != nullptr) {
    if (strncmp(mentry->mnt_dir, path, path_len) == 0) {
      to_unmount.push_front(std::string(mentry->mnt_dir));
    }
  }
  endmntent(fp);

  for (const auto& path : to_unmount) {
    if (umount2(path.c_str(), MNT_DETACH)) {
      ALOGW("Failed to unmount %s: %s", path.c_str(), strerror(errno));
    }
  }
  return 0;
}

static void PrepareDir(const std::string& dir, mode_t mode, uid_t uid, gid_t gid,
                      fail_fn_t fail_fn) {
  if (fs_prepare_dir(dir.c_str(), mode, uid, gid) != 0) {
    fail_fn(CREATE_ERROR("fs_prepare_dir failed on %s: %s",
                         dir.c_str(), strerror(errno)));
  }
}

static void PrepareDirIfNotPresent(const std::string& dir, mode_t mode, uid_t uid, gid_t gid,
                      fail_fn_t fail_fn) {
  struct stat sb;
  if (TEMP_FAILURE_RETRY(stat(dir.c_str(), &sb)) != -1) {
    // Directory exists already
    return;
  }
  PrepareDir(dir, mode, uid, gid, fail_fn);
}

static bool BindMount(const std::string& source_dir, const std::string& target_dir) {
  return !(TEMP_FAILURE_RETRY(mount(source_dir.c_str(), target_dir.c_str(), nullptr,
                                    MS_BIND | MS_REC, nullptr)) == -1);
}

static void BindMount(const std::string& source_dir, const std::string& target_dir,
                      fail_fn_t fail_fn) {
  if (!BindMount(source_dir, target_dir)) {
    fail_fn(CREATE_ERROR("Failed to mount %s to %s: %s",
                         source_dir.c_str(), target_dir.c_str(), strerror(errno)));
  }
}

static void MountAppDataTmpFs(const std::string& target_dir,
                      fail_fn_t fail_fn) {
  if (TEMP_FAILURE_RETRY(mount("tmpfs", target_dir.c_str(), "tmpfs",
                               MS_NOSUID | MS_NODEV | MS_NOEXEC, "uid=0,gid=0,mode=0751")) == -1) {
    fail_fn(CREATE_ERROR("Failed to mount tmpfs to %s: %s",
                         target_dir.c_str(), strerror(errno)));
  }
}

// Create a private mount namespace and bind mount appropriate emulated
// storage for the given user.
static void MountEmulatedStorage(uid_t uid, jint mount_mode,
        bool force_mount_namespace,
        fail_fn_t fail_fn) {
  // See storage config details at http://source.android.com/tech/storage/
  ATRACE_CALL();

  if (mount_mode < 0 || mount_mode >= MOUNT_EXTERNAL_COUNT) {
    fail_fn(CREATE_ERROR("Unknown mount_mode: %d", mount_mode));
  }

  if (mount_mode == MOUNT_EXTERNAL_NONE && !force_mount_namespace) {
    // Valid default of no storage visible
    return;
  }

  // Create a second private mount namespace for our process
  ensureInAppMountNamespace(fail_fn);

  // Handle force_mount_namespace with MOUNT_EXTERNAL_NONE.
  if (mount_mode == MOUNT_EXTERNAL_NONE) {
    return;
  }

  const userid_t user_id = multiuser_get_user_id(uid);
  const std::string user_source = StringPrintf("/mnt/user/%d", user_id);
  // Shell is neither AID_ROOT nor AID_EVERYBODY. Since it equally needs 'execute' access to
  // /mnt/user/0 to 'adb shell ls /sdcard' for instance, we set the uid bit of /mnt/user/0 to
  // AID_SHELL. This gives shell access along with apps running as group everybody (user 0 apps)
  // These bits should be consistent with what is set in vold in
  // Utils#MountUserFuse on FUSE volume mount
  PrepareDir(user_source, 0710, user_id ? AID_ROOT : AID_SHELL,
             multiuser_get_uid(user_id, AID_EVERYBODY), fail_fn);

  bool isAppDataIsolationEnabled = GetBoolProperty(kVoldAppDataIsolation, false);

  if (mount_mode == MOUNT_EXTERNAL_PASS_THROUGH) {
      const std::string pass_through_source = StringPrintf("/mnt/pass_through/%d", user_id);
      PrepareDir(pass_through_source, 0710, AID_ROOT, AID_MEDIA_RW, fail_fn);
      BindMount(pass_through_source, "/storage", fail_fn);
  } else if (mount_mode == MOUNT_EXTERNAL_INSTALLER) {
      const std::string installer_source = StringPrintf("/mnt/installer/%d", user_id);
      BindMount(installer_source, "/storage", fail_fn);
  } else if (isAppDataIsolationEnabled && mount_mode == MOUNT_EXTERNAL_ANDROID_WRITABLE) {
      const std::string writable_source = StringPrintf("/mnt/androidwritable/%d", user_id);
      BindMount(writable_source, "/storage", fail_fn);
  } else {
      BindMount(user_source, "/storage", fail_fn);
  }
}

// Utility to close down the Zygote socket file descriptors while
// the child is still running as root with Zygote's privileges.  Each
// descriptor (if any) is closed via dup3(), replacing it with a valid
// (open) descriptor to /dev/null.

static void DetachDescriptors(JNIEnv* env,
                              const std::vector<int>& fds_to_close,
                              fail_fn_t fail_fn) {

  if (fds_to_close.size() > 0) {
    android::base::unique_fd devnull_fd(open("/dev/null", O_RDWR | O_CLOEXEC));
    if (devnull_fd == -1) {
      fail_fn(std::string("Failed to open /dev/null: ").append(strerror(errno)));
    }

    for (int fd : fds_to_close) {
      ALOGV("Switching descriptor %d to /dev/null", fd);
      if (TEMP_FAILURE_RETRY(dup3(devnull_fd, fd, O_CLOEXEC)) == -1) {
        fail_fn(StringPrintf("Failed dup3() on descriptor %d: %s", fd, strerror(errno)));
      }
    }
  }
}

void SetThreadName(const std::string& thread_name) {
  bool hasAt = false;
  bool hasDot = false;

  for (const char str_el : thread_name) {
    if (str_el == '.') {
      hasDot = true;
    } else if (str_el == '@') {
      hasAt = true;
    }
  }

  const char* name_start_ptr = thread_name.c_str();
  if (thread_name.length() >= MAX_NAME_LENGTH && !hasAt && hasDot) {
    name_start_ptr += thread_name.length() - MAX_NAME_LENGTH;
  }

  // pthread_setname_np fails rather than truncating long strings.
  char buf[16];       // MAX_TASK_COMM_LEN=16 is hard-coded into bionic
  strlcpy(buf, name_start_ptr, sizeof(buf));
  errno = pthread_setname_np(pthread_self(), buf);
  if (errno != 0) {
    ALOGW("Unable to set the name of current thread to '%s': %s", buf, strerror(errno));
  }
  // Update base::logging default tag.
  android::base::SetDefaultTag(buf);
}

/**
 * A helper method for converting managed strings to native strings.  A fatal
 * error is generated if a problem is encountered in extracting a non-null
 * string.
 *
 * @param env  Managed runtime environment
 * @param process_name  A native representation of the process name
 * @param managed_process_name  A managed representation of the process name
 * @param managed_string  The managed string to extract
 *
 * @return An empty option if the managed string is null.  A optional-wrapped
 * string otherwise.
 */
static std::optional<std::string> ExtractJString(JNIEnv* env,
                                                 const char* process_name,
                                                 jstring managed_process_name,
                                                 jstring managed_string) {
  if (managed_string == nullptr) {
    return std::nullopt;
  } else {
    ScopedUtfChars scoped_string_chars(env, managed_string);

    if (scoped_string_chars.c_str() != nullptr) {
      return std::optional<std::string>(scoped_string_chars.c_str());
    } else {
      ZygoteFailure(env, process_name, managed_process_name, "Failed to extract JString.");
    }
  }
}

/**
 * A helper method for converting managed string arrays to native vectors.  A
 * fatal error is generated if a problem is encountered in extracting a non-null array.
 *
 * @param env  Managed runtime environment
 * @param process_name  A native representation of the process name
 * @param managed_process_name  A managed representation of the process name
 * @param managed_array  The managed integer array to extract
 *
 * @return An empty option if the managed array is null.  A optional-wrapped
 * vector otherwise.
 */
static std::optional<std::vector<int>> ExtractJIntArray(JNIEnv* env,
                                                        const char* process_name,
                                                        jstring managed_process_name,
                                                        jintArray managed_array) {
  if (managed_array == nullptr) {
    return std::nullopt;
  } else {
    ScopedIntArrayRO managed_array_handle(env, managed_array);

    if (managed_array_handle.get() != nullptr) {
      std::vector<int> native_array;
      native_array.reserve(managed_array_handle.size());

      for (size_t array_index = 0; array_index < managed_array_handle.size(); ++array_index) {
        native_array.push_back(managed_array_handle[array_index]);
      }

      return std::move(native_array);

    } else {
      ZygoteFailure(env, process_name, managed_process_name, "Failed to extract JIntArray.");
    }
  }
}

/**
 * A utility function for blocking signals.
 *
 * @param signum  Signal number to block
 * @param fail_fn  Fatal error reporting function
 *
 * @see ZygoteFailure
 */
static void BlockSignal(int signum, fail_fn_t fail_fn) {
  sigset_t sigs;
  sigemptyset(&sigs);
  sigaddset(&sigs, signum);

  if (sigprocmask(SIG_BLOCK, &sigs, nullptr) == -1) {
    fail_fn(CREATE_ERROR("Failed to block signal %s: %s", strsignal(signum), strerror(errno)));
  }
}


/**
 * A utility function for unblocking signals.
 *
 * @param signum  Signal number to unblock
 * @param fail_fn  Fatal error reporting function
 *
 * @see ZygoteFailure
 */
static void UnblockSignal(int signum, fail_fn_t fail_fn) {
  sigset_t sigs;
  sigemptyset(&sigs);
  sigaddset(&sigs, signum);

  if (sigprocmask(SIG_UNBLOCK, &sigs, nullptr) == -1) {
    fail_fn(CREATE_ERROR("Failed to un-block signal %s: %s", strsignal(signum), strerror(errno)));
  }
}

static void ClearUsapTable() {
  for (UsapTableEntry& entry : gUsapTable) {
    entry.Clear();
  }

  gUsapPoolCount = 0;
}

// Create an app data directory over tmpfs overlayed CE / DE storage, and bind mount it
// from the actual app data directory in data mirror.
static bool createAndMountAppData(std::string_view package_name,
    std::string_view mirror_pkg_dir_name, std::string_view mirror_data_path,
    std::string_view actual_data_path, fail_fn_t fail_fn, bool call_fail_fn) {

  char mirrorAppDataPath[PATH_MAX];
  char actualAppDataPath[PATH_MAX];
  snprintf(mirrorAppDataPath, PATH_MAX, "%s/%s", mirror_data_path.data(),
      mirror_pkg_dir_name.data());
  snprintf(actualAppDataPath, PATH_MAX, "%s/%s", actual_data_path.data(), package_name.data());

  PrepareDir(actualAppDataPath, 0700, AID_ROOT, AID_ROOT, fail_fn);

  // Bind mount from original app data directory in mirror.
  if (call_fail_fn) {
    BindMount(mirrorAppDataPath, actualAppDataPath, fail_fn);
  } else if(!BindMount(mirrorAppDataPath, actualAppDataPath)) {
    ALOGW("Failed to mount %s to %s: %s",
          mirrorAppDataPath, actualAppDataPath, strerror(errno));
    return false;
  }
  return true;
}

// There is an app data directory over tmpfs overlaid CE / DE storage
// bind mount it from the actual app data directory in data mirror.
static void mountAppData(std::string_view package_name,
    std::string_view mirror_pkg_dir_name, std::string_view mirror_data_path,
    std::string_view actual_data_path, fail_fn_t fail_fn) {

  char mirrorAppDataPath[PATH_MAX];
  char actualAppDataPath[PATH_MAX];
  snprintf(mirrorAppDataPath, PATH_MAX, "%s/%s", mirror_data_path.data(),
      mirror_pkg_dir_name.data());
  snprintf(actualAppDataPath, PATH_MAX, "%s/%s", actual_data_path.data(), package_name.data());

  // Bind mount from original app data directory in mirror.
  BindMount(mirrorAppDataPath, actualAppDataPath, fail_fn);
}

// Get the directory name stored in /data/data. If device is unlocked it should be the same as
// package name, otherwise it will be an encrypted name but with same inode number.
static std::string getAppDataDirName(std::string_view parent_path, std::string_view package_name,
      long long ce_data_inode, fail_fn_t fail_fn) {
  // Check if directory exists
  char tmpPath[PATH_MAX];
  snprintf(tmpPath, PATH_MAX, "%s/%s", parent_path.data(), package_name.data());
  struct stat s;
  int err = stat(tmpPath, &s);
  if (err == 0) {
    // Directory exists, so return the directory name
    return package_name.data();
  } else {
    if (errno != ENOENT) {
      fail_fn(CREATE_ERROR("Unexpected error in getAppDataDirName: %s", strerror(errno)));
      return nullptr;
    }
    {
      // Directory doesn't exist, try to search the name from inode
      std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(parent_path.data()), closedir);
      if (dir == nullptr) {
        fail_fn(CREATE_ERROR("Failed to opendir %s", parent_path.data()));
      }
      struct dirent* ent;
      while ((ent = readdir(dir.get()))) {
        if (ent->d_ino == ce_data_inode) {
          return ent->d_name;
        }
      }
    }

    // Fallback due to b/145989852, ce_data_inode stored in package manager may be corrupted
    // if ino_t is 32 bits.
    ino_t fixed_ce_data_inode = 0;
    if ((ce_data_inode & UPPER_HALF_WORD_MASK) == UPPER_HALF_WORD_MASK) {
      fixed_ce_data_inode = ce_data_inode & LOWER_HALF_WORD_MASK;
    } else if ((ce_data_inode & LOWER_HALF_WORD_MASK) == LOWER_HALF_WORD_MASK) {
      fixed_ce_data_inode = ((ce_data_inode >> 32) & LOWER_HALF_WORD_MASK);
    }
    if (fixed_ce_data_inode != 0) {
      std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(parent_path.data()), closedir);
      if (dir == nullptr) {
        fail_fn(CREATE_ERROR("Failed to opendir %s", parent_path.data()));
      }
      struct dirent* ent;
      while ((ent = readdir(dir.get()))) {
        if (ent->d_ino == fixed_ce_data_inode) {
          long long d_ino = ent->d_ino;
          ALOGW("Fallback success inode %lld -> %lld", ce_data_inode, d_ino);
          return ent->d_name;
        }
      }
    }
    // Fallback done

    fail_fn(CREATE_ERROR("Unable to find %s:%lld in %s", package_name.data(),
        ce_data_inode, parent_path.data()));
    return nullptr;
  }
}

// Isolate app's data directory, by mounting a tmpfs on CE DE storage,
// and create and bind mount app data in related_packages.
static void isolateAppDataPerPackage(int userId, std::string_view package_name,
    std::string_view volume_uuid, long long ce_data_inode, std::string_view actualCePath,
    std::string_view actualDePath, fail_fn_t fail_fn) {

  char mirrorCePath[PATH_MAX];
  char mirrorDePath[PATH_MAX];
  char mirrorCeParent[PATH_MAX];
  snprintf(mirrorCeParent, PATH_MAX, "/data_mirror/data_ce/%s", volume_uuid.data());
  snprintf(mirrorCePath, PATH_MAX, "%s/%d", mirrorCeParent, userId);
  snprintf(mirrorDePath, PATH_MAX, "/data_mirror/data_de/%s/%d", volume_uuid.data(), userId);

  createAndMountAppData(package_name, package_name, mirrorDePath, actualDePath, fail_fn,
                        true /*call_fail_fn*/);

  std::string ce_data_path = getAppDataDirName(mirrorCePath, package_name, ce_data_inode, fail_fn);
  if (!createAndMountAppData(package_name, ce_data_path, mirrorCePath, actualCePath, fail_fn,
                             false /*call_fail_fn*/)) {
    // CE might unlocks and the name is decrypted
    // get the name and mount again
    ce_data_path=getAppDataDirName(mirrorCePath, package_name, ce_data_inode, fail_fn);
    mountAppData(package_name, ce_data_path, mirrorCePath, actualCePath, fail_fn);
  }
}

// Relabel directory
static void relabelDir(const char* path, const char* context, fail_fn_t fail_fn) {
  if (setfilecon(path, context) != 0) {
    fail_fn(CREATE_ERROR("Failed to setfilecon %s %s", path, strerror(errno)));
  }
}

// Relabel all directories under a path non-recursively.
static void relabelAllDirs(const char* path, const char* context, fail_fn_t fail_fn) {
  DIR* dir = opendir(path);
  if (dir == nullptr) {
    fail_fn(CREATE_ERROR("Failed to opendir %s", path));
  }
  struct dirent* ent;
  while ((ent = readdir(dir))) {
    if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) continue;
    auto filePath = StringPrintf("%s/%s", path, ent->d_name);
    if (ent->d_type == DT_DIR) {
      relabelDir(filePath.c_str(), context, fail_fn);
    } else if (ent->d_type == DT_LNK) {
      if (lsetfilecon(filePath.c_str(), context) != 0) {
        fail_fn(CREATE_ERROR("Failed to lsetfilecon %s %s", filePath.c_str(), strerror(errno)));
      }
    } else {
      fail_fn(CREATE_ERROR("Unexpected type: %d %s", ent->d_type, filePath.c_str()));
    }
  }
  closedir(dir);
}

static bool is_sdk_sandbox_uid(uid_t uid) {
    appid_t appId = multiuser_get_app_id(uid);
    return appId >= AID_SDK_SANDBOX_PROCESS_START && appId <= AID_SDK_SANDBOX_PROCESS_END;
}

/**
 * Make other apps data directory not visible in CE, DE storage.
 *
 * Apps without app data isolation can detect if another app is installed on system,
 * by "touching" other apps data directory like /data/data/com.whatsapp, if it returns
 * "Permission denied" it means apps installed, otherwise it returns "File not found".
 * Traditional file permissions or SELinux can only block accessing those directories but
 * can't fix fingerprinting like this.
 * We fix it by "overlaying" data directory, and only relevant app data packages exists
 * in data directories.
 *
 * Steps:
 * 1). Collect a list of all related apps (apps with same uid and allowlisted apps) data info
 * (package name, data stored volume uuid, and inode number of its CE data directory)
 * 2). Mount tmpfs on /data/data, /data/user(_de) and /mnt/expand, so apps no longer
 * able to access apps data directly.
 * 3). For each related app, create its app data directory and bind mount the actual content
 * from apps data mirror directory. This works on both CE and DE storage, as DE storage
 * is always available even storage is FBE locked, while we use inode number to find
 * the encrypted DE directory in mirror so we can still bind mount it successfully.
 *
 * Example:
 * 0). Assuming com.android.foo CE data is stored in /data/data and no shared uid
 * 1). Mount a tmpfs on /data/data, /data/user, /data/user_de, /mnt/expand
 * List = ["com.android.foo", "null" (volume uuid "null"=default),
 * 123456 (inode number)]
 * 2). On DE storage, we create a directory /data/user_de/0/com.com.android.foo, and bind
 * mount (in the app's mount namespace) it from /data_mirror/data_de/0/com.android.foo.
 * 3). We do similar for CE storage. But in direct boot mode, as /data_mirror/data_ce/0/ is
 * encrypted, we can't find a directory with name com.android.foo on it, so we will
 * use the inode number to find the right directory instead, which that directory content will
 * be decrypted after storage is decrypted.
 *
 */
static void isolateAppData(JNIEnv* env, const std::vector<std::string>& merged_data_info_list,
    uid_t uid, const char* process_name,
    jstring managed_nice_name, fail_fn_t fail_fn) {

  const userid_t userId = multiuser_get_user_id(uid);

  int size = merged_data_info_list.size();

  // Mount tmpfs on all possible data directories, so app no longer see the original apps data.
  char internalCePath[PATH_MAX];
  char internalLegacyCePath[PATH_MAX];
  char internalDePath[PATH_MAX];
  char externalPrivateMountPath[PATH_MAX];

  snprintf(internalCePath, PATH_MAX, "/data/user");
  snprintf(internalLegacyCePath, PATH_MAX, "/data/data");
  snprintf(internalDePath, PATH_MAX, "/data/user_de");
  snprintf(externalPrivateMountPath, PATH_MAX, "/mnt/expand");

  char* dataDataContext = nullptr;
  if (getfilecon(internalDePath, &dataDataContext) < 0) {
    fail_fn(CREATE_ERROR("Unable to getfilecon on %s %s", internalDePath,
        strerror(errno)));
  }

  MountAppDataTmpFs(internalLegacyCePath, fail_fn);
  MountAppDataTmpFs(internalCePath, fail_fn);
  MountAppDataTmpFs(internalDePath, fail_fn);

  // Mount tmpfs on all external vols DE and CE storage
  DIR* dir = opendir(externalPrivateMountPath);
  if (dir == nullptr) {
    fail_fn(CREATE_ERROR("Failed to opendir %s", externalPrivateMountPath));
  }
  struct dirent* ent;
  while ((ent = readdir(dir))) {
    if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) continue;
    if (ent->d_type != DT_DIR) {
      fail_fn(CREATE_ERROR("Unexpected type: %d %s", ent->d_type, ent->d_name));
    }
    auto volPath = StringPrintf("%s/%s", externalPrivateMountPath, ent->d_name);
    auto cePath = StringPrintf("%s/user", volPath.c_str());
    auto dePath = StringPrintf("%s/user_de", volPath.c_str());
    // Wait until dir user is created.
    WaitUntilDirReady(cePath.c_str(), fail_fn);
    MountAppDataTmpFs(cePath.c_str(), fail_fn);
    // Wait until dir user_de is created.
    WaitUntilDirReady(dePath.c_str(), fail_fn);
    MountAppDataTmpFs(dePath.c_str(), fail_fn);
  }
  closedir(dir);

  // No bind mounting of app data should occur in the case of a sandbox process since SDK sandboxes
  // should not be able to read app data. Tmpfs was mounted however since a sandbox should not have
  // access to app data.
  if (!is_sdk_sandbox_uid(uid)) {
      // Prepare default dirs for user 0 as user 0 always exists.
      int result = symlink("/data/data", "/data/user/0");
      if (result != 0) {
          fail_fn(CREATE_ERROR("Failed to create symlink /data/user/0 %s", strerror(errno)));
      }
      PrepareDirIfNotPresent("/data/user_de/0", DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT,
                             fail_fn);

      for (int i = 0; i < size; i += 3) {
          std::string const& packageName = merged_data_info_list[i];
          std::string const& volUuid = merged_data_info_list[i + 1];
          std::string const& inode = merged_data_info_list[i + 2];

          std::string::size_type sz;
          long long ceDataInode = std::stoll(inode, &sz);

          std::string actualCePath, actualDePath;
          if (volUuid.compare("null") != 0) {
              // Volume that is stored in /mnt/expand
              char volPath[PATH_MAX];
              char volCePath[PATH_MAX];
              char volDePath[PATH_MAX];
              char volCeUserPath[PATH_MAX];
              char volDeUserPath[PATH_MAX];

              snprintf(volPath, PATH_MAX, "/mnt/expand/%s", volUuid.c_str());
              snprintf(volCePath, PATH_MAX, "%s/user", volPath);
              snprintf(volDePath, PATH_MAX, "%s/user_de", volPath);
              snprintf(volCeUserPath, PATH_MAX, "%s/%d", volCePath, userId);
              snprintf(volDeUserPath, PATH_MAX, "%s/%d", volDePath, userId);

              PrepareDirIfNotPresent(volPath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT,
                                     fail_fn);
              PrepareDirIfNotPresent(volCePath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT,
                                     fail_fn);
              PrepareDirIfNotPresent(volDePath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT,
                                     fail_fn);
              PrepareDirIfNotPresent(volCeUserPath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT,
                                     fail_fn);
              PrepareDirIfNotPresent(volDeUserPath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT,
                                     fail_fn);

              actualCePath = volCeUserPath;
              actualDePath = volDeUserPath;
          } else {
              // Internal volume that stored in /data
              char internalCeUserPath[PATH_MAX];
              char internalDeUserPath[PATH_MAX];
              snprintf(internalCeUserPath, PATH_MAX, "/data/user/%d", userId);
              snprintf(internalDeUserPath, PATH_MAX, "/data/user_de/%d", userId);
              // If it's not user 0, create /data/user/$USER.
              if (userId == 0) {
                  actualCePath = internalLegacyCePath;
              } else {
                  PrepareDirIfNotPresent(internalCeUserPath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT,
                                         AID_ROOT, fail_fn);
                  actualCePath = internalCeUserPath;
              }
              PrepareDirIfNotPresent(internalDeUserPath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT,
                                     AID_ROOT, fail_fn);
              actualDePath = internalDeUserPath;
          }
          isolateAppDataPerPackage(userId, packageName, volUuid, ceDataInode, actualCePath,
                                   actualDePath, fail_fn);
      }
  }

  // We set the label AFTER everything is done, as we are applying
  // the file operations on tmpfs. If we set the label when we mount
  // tmpfs, SELinux will not happy as we are changing system_data_files.
  // Relabel dir under /data/user, including /data/user/0
  relabelAllDirs(internalCePath, dataDataContext, fail_fn);

  // Relabel /data/user
  relabelDir(internalCePath, dataDataContext, fail_fn);

  // Relabel /data/data
  relabelDir(internalLegacyCePath, dataDataContext, fail_fn);

  // Relabel dir under /data/user_de
  relabelAllDirs(internalDePath, dataDataContext, fail_fn);

  // Relabel /data/user_de
  relabelDir(internalDePath, dataDataContext, fail_fn);

  // Relabel CE and DE dirs under /mnt/expand
  dir = opendir(externalPrivateMountPath);
  if (dir == nullptr) {
    fail_fn(CREATE_ERROR("Failed to opendir %s", externalPrivateMountPath));
  }
  while ((ent = readdir(dir))) {
    if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) continue;
    auto volPath = StringPrintf("%s/%s", externalPrivateMountPath, ent->d_name);
    auto cePath = StringPrintf("%s/user", volPath.c_str());
    auto dePath = StringPrintf("%s/user_de", volPath.c_str());

    relabelAllDirs(cePath.c_str(), dataDataContext, fail_fn);
    relabelDir(cePath.c_str(), dataDataContext, fail_fn);
    relabelAllDirs(dePath.c_str(), dataDataContext, fail_fn);
    relabelDir(dePath.c_str(), dataDataContext, fail_fn);
  }
  closedir(dir);

  freecon(dataDataContext);
}

/**
 * Without sdk sandbox data isolation, the sandbox could detect if another app is installed on the
 * system by "touching" other data directories like /data/misc_ce/0/sdksandbox/com.whatsapp, similar
 * to apps without app data isolation (see {@link #isolateAppData()}).
 *
 * To prevent this, tmpfs is mounted onto misc_ce and misc_de directories on all possible volumes in
 * a separate mount namespace. The sandbox directory path is then created containing the name of the
 * client app package associated with the sdk sandbox. The contents for this (sdk level storage and
 * shared sdk storage) are bind mounted from the sandbox data mirror.
 */
static void isolateSdkSandboxData(JNIEnv* env, jobjectArray pkg_data_info_list, uid_t uid,
                                  const char* process_name, jstring managed_nice_name,
                                  fail_fn_t fail_fn) {
    const userid_t userId = multiuser_get_user_id(uid);

    int size = (pkg_data_info_list != nullptr) ? env->GetArrayLength(pkg_data_info_list) : 0;
    // The sandbox should only have information of one associated client app (package, uuid, inode)
    if (size != 3) {
        fail_fn(CREATE_ERROR(
                "Unable to isolate sandbox data, incorrect associated app information"));
    }

    auto extract_fn = [env, process_name, managed_nice_name,
                       pkg_data_info_list](int info_list_idx) {
        jstring jstr = (jstring)(env->GetObjectArrayElement(pkg_data_info_list, info_list_idx));
        return ExtractJString(env, process_name, managed_nice_name, jstr).value();
    };
    std::string packageName = extract_fn(0);
    std::string volUuid = extract_fn(1);

    char internalCePath[PATH_MAX];
    char internalDePath[PATH_MAX];
    char externalPrivateMountPath[PATH_MAX];
    snprintf(internalCePath, PATH_MAX, "/data/misc_ce");
    snprintf(internalDePath, PATH_MAX, "/data/misc_de");
    snprintf(externalPrivateMountPath, PATH_MAX, "/mnt/expand");

    char ceUserPath[PATH_MAX];
    char deUserPath[PATH_MAX];
    if (volUuid != "null") {
        snprintf(ceUserPath, PATH_MAX, "%s/%s/misc_ce/%d", externalPrivateMountPath,
                 volUuid.c_str(), userId);
        snprintf(deUserPath, PATH_MAX, "%s/%s/misc_de/%d", externalPrivateMountPath,
                 volUuid.c_str(), userId);
    } else {
        snprintf(ceUserPath, PATH_MAX, "%s/%d", internalCePath, userId);
        snprintf(deUserPath, PATH_MAX, "%s/%d", internalDePath, userId);
    }

    char ceSandboxPath[PATH_MAX];
    char deSandboxPath[PATH_MAX];
    snprintf(ceSandboxPath, PATH_MAX, "%s/sdksandbox", ceUserPath);
    snprintf(deSandboxPath, PATH_MAX, "%s/sdksandbox", deUserPath);

    // If the client app using the sandbox has been installed when the device is locked and the
    // sandbox starts up when the device is locked, sandbox storage might not have been created.
    // In that case, mount tmpfs for data isolation, but don't bind mount.
    bool bindMountCeSandboxDataDirs = true;
    bool bindMountDeSandboxDataDirs = true;
    if (access(ceSandboxPath, F_OK) != 0) {
        bindMountCeSandboxDataDirs = false;
    }
    if (access(deSandboxPath, F_OK) != 0) {
        bindMountDeSandboxDataDirs = false;
    }

    char* context = nullptr;
    char* userContext = nullptr;
    char* sandboxContext = nullptr;
    if (getfilecon(internalDePath, &context) < 0) {
        fail_fn(CREATE_ERROR("Unable to getfilecon on %s %s", internalDePath, strerror(errno)));
    }
    if (bindMountDeSandboxDataDirs) {
        if (getfilecon(deUserPath, &userContext) < 0) {
            fail_fn(CREATE_ERROR("Unable to getfilecon on %s %s", deUserPath, strerror(errno)));
        }
        if (getfilecon(deSandboxPath, &sandboxContext) < 0) {
            fail_fn(CREATE_ERROR("Unable to getfilecon on %s %s", deSandboxPath, strerror(errno)));
        }
    }

    MountAppDataTmpFs(internalCePath, fail_fn);
    MountAppDataTmpFs(internalDePath, fail_fn);

    // Mount tmpfs on all external volumes
    DIR* dir = opendir(externalPrivateMountPath);
    if (dir == nullptr) {
        fail_fn(CREATE_ERROR("Failed to opendir %s", externalPrivateMountPath));
    }
    struct dirent* ent;
    while ((ent = readdir(dir))) {
        if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) continue;
        if (ent->d_type != DT_DIR) {
            fail_fn(CREATE_ERROR("Unexpected type: %d %s", ent->d_type, ent->d_name));
        }
        auto volPath = StringPrintf("%s/%s", externalPrivateMountPath, ent->d_name);
        auto externalCePath = StringPrintf("%s/misc_ce", volPath.c_str());
        auto externalDePath = StringPrintf("%s/misc_de", volPath.c_str());

        WaitUntilDirReady(externalCePath.c_str(), fail_fn);
        MountAppDataTmpFs(externalCePath.c_str(), fail_fn);
        WaitUntilDirReady(externalDePath.c_str(), fail_fn);
        MountAppDataTmpFs(externalDePath.c_str(), fail_fn);
    }
    closedir(dir);

    char mirrorCeSandboxPath[PATH_MAX];
    char mirrorDeSandboxPath[PATH_MAX];
    snprintf(mirrorCeSandboxPath, PATH_MAX, "/data_mirror/misc_ce/%s/%d/sdksandbox",
             volUuid.c_str(), userId);
    snprintf(mirrorDeSandboxPath, PATH_MAX, "/data_mirror/misc_de/%s/%d/sdksandbox",
             volUuid.c_str(), userId);

    if (bindMountCeSandboxDataDirs) {
        PrepareDir(ceUserPath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT, fail_fn);
        PrepareDir(ceSandboxPath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT, fail_fn);
        // TODO(b/231322885): Use inode numbers to find the correct app path when the device locked.
        createAndMountAppData(packageName, packageName, mirrorCeSandboxPath, ceSandboxPath, fail_fn,
                              true /*call_fail_fn*/);

        relabelDir(ceSandboxPath, sandboxContext, fail_fn);
        relabelDir(ceUserPath, userContext, fail_fn);
    }
    if (bindMountDeSandboxDataDirs) {
        PrepareDir(deUserPath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT, fail_fn);
        PrepareDir(deSandboxPath, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT, fail_fn);
        createAndMountAppData(packageName, packageName, mirrorDeSandboxPath, deSandboxPath, fail_fn,
                              true /*call_fail_fn*/);

        relabelDir(deSandboxPath, sandboxContext, fail_fn);
        relabelDir(deUserPath, userContext, fail_fn);
    }

    // We set the label AFTER everything is done, as we are applying
    // the file operations on tmpfs. If we set the label when we mount
    // tmpfs, SELinux will not happy as we are changing system_data_files.
    relabelDir(internalCePath, context, fail_fn);
    relabelDir(internalDePath, context, fail_fn);

    // Relabel CE and DE dirs under /mnt/expand
    dir = opendir(externalPrivateMountPath);
    if (dir == nullptr) {
        fail_fn(CREATE_ERROR("Failed to opendir %s", externalPrivateMountPath));
    }
    while ((ent = readdir(dir))) {
        if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) continue;
        auto volPath = StringPrintf("%s/%s", externalPrivateMountPath, ent->d_name);
        auto externalCePath = StringPrintf("%s/misc_ce", volPath.c_str());
        auto externalDePath = StringPrintf("%s/misc_de", volPath.c_str());
        relabelDir(externalCePath.c_str(), context, fail_fn);
        relabelDir(externalDePath.c_str(), context, fail_fn);
    }
    closedir(dir);

    if (bindMountDeSandboxDataDirs) {
        freecon(sandboxContext);
        freecon(userContext);
    }
    freecon(context);
}

static void insertPackagesToMergedList(JNIEnv* env,
  std::vector<std::string>& merged_data_info_list,
  jobjectArray data_info_list, const char* process_name,
  jstring managed_nice_name, fail_fn_t fail_fn) {

  auto extract_fn = std::bind(ExtractJString, env, process_name, managed_nice_name, _1);

  int size = (data_info_list != nullptr) ? env->GetArrayLength(data_info_list) : 0;
  // Size should be a multiple of 3, as it contains list of <package_name, volume_uuid, inode>
  if ((size % 3) != 0) {
    fail_fn(CREATE_ERROR("Wrong data_info_list size %d", size));
  }

  for (int i = 0; i < size; i += 3) {
    jstring package_str = (jstring) (env->GetObjectArrayElement(data_info_list, i));
    std::string packageName = extract_fn(package_str).value();
    merged_data_info_list.push_back(packageName);

    jstring vol_str = (jstring) (env->GetObjectArrayElement(data_info_list, i + 1));
    std::string volUuid = extract_fn(vol_str).value();
    merged_data_info_list.push_back(volUuid);

    jstring inode_str = (jstring) (env->GetObjectArrayElement(data_info_list, i + 2));
    std::string inode = extract_fn(inode_str).value();
    merged_data_info_list.push_back(inode);
  }
}

static void isolateAppData(JNIEnv* env, jobjectArray pkg_data_info_list,
                           jobjectArray allowlisted_data_info_list, uid_t uid,
                           const char* process_name, jstring managed_nice_name, fail_fn_t fail_fn) {
    std::vector<std::string> merged_data_info_list;
    insertPackagesToMergedList(env, merged_data_info_list, pkg_data_info_list, process_name,
                               managed_nice_name, fail_fn);
    insertPackagesToMergedList(env, merged_data_info_list, allowlisted_data_info_list, process_name,
                               managed_nice_name, fail_fn);

    isolateAppData(env, merged_data_info_list, uid, process_name, managed_nice_name, fail_fn);
}

/**
 * Like isolateAppData(), isolate jit profile directories, so apps don't see what
 * other apps are installed by reading content inside /data/misc/profiles/cur.
 *
 * The implementation is similar to isolateAppData(), it creates a tmpfs
 * on /data/misc/profiles/cur, and bind mounts related package profiles to it.
 */
static void isolateJitProfile(JNIEnv* env, jobjectArray pkg_data_info_list,
    uid_t uid, const char* process_name, jstring managed_nice_name,
    fail_fn_t fail_fn) {

  auto extract_fn = std::bind(ExtractJString, env, process_name, managed_nice_name, _1);
  const userid_t user_id = multiuser_get_user_id(uid);

  int size = (pkg_data_info_list != nullptr) ? env->GetArrayLength(pkg_data_info_list) : 0;
  // Size should be a multiple of 3, as it contains list of <package_name, volume_uuid, inode>
  if ((size % 3) != 0) {
    fail_fn(CREATE_ERROR("Wrong pkg_inode_list size %d", size));
  }

  // Mount (namespace) tmpfs on profile directory, so apps no longer access
  // the original profile directory anymore.
  MountAppDataTmpFs(kCurProfileDirPath, fail_fn);
  MountAppDataTmpFs(kRefProfileDirPath, fail_fn);

  // Sandbox processes do not have JIT profile, so no data needs to be bind mounted. However, it
  // should still not have access to JIT profile, so tmpfs is mounted.
  if (is_sdk_sandbox_uid(uid)) {
      return;
  }

  // Create profile directory for this user.
  std::string actualCurUserProfile = StringPrintf("%s/%d", kCurProfileDirPath, user_id);
  PrepareDir(actualCurUserProfile, DEFAULT_DATA_DIR_PERMISSION, AID_ROOT, AID_ROOT, fail_fn);

  for (int i = 0; i < size; i += 3) {
    jstring package_str = (jstring) (env->GetObjectArrayElement(pkg_data_info_list, i));
    std::string packageName = extract_fn(package_str).value();

    std::string actualCurPackageProfile = StringPrintf("%s/%s", actualCurUserProfile.c_str(),
        packageName.c_str());
    std::string mirrorCurPackageProfile = StringPrintf("/data_mirror/cur_profiles/%d/%s",
        user_id, packageName.c_str());
    std::string actualRefPackageProfile = StringPrintf("%s/%s", kRefProfileDirPath,
        packageName.c_str());
    std::string mirrorRefPackageProfile = StringPrintf("/data_mirror/ref_profiles/%s",
        packageName.c_str());

    if (access(mirrorCurPackageProfile.c_str(), F_OK) != 0) {
      ALOGW("Can't access app profile directory: %s", mirrorCurPackageProfile.c_str());
      continue;
    }
    if (access(mirrorRefPackageProfile.c_str(), F_OK) != 0) {
      ALOGW("Can't access app profile directory: %s", mirrorRefPackageProfile.c_str());
      continue;
    }

    PrepareDir(actualCurPackageProfile, DEFAULT_DATA_DIR_PERMISSION, uid, uid, fail_fn);
    BindMount(mirrorCurPackageProfile, actualCurPackageProfile, fail_fn);
    PrepareDir(actualRefPackageProfile, DEFAULT_DATA_DIR_PERMISSION, uid, uid, fail_fn);
    BindMount(mirrorRefPackageProfile, actualRefPackageProfile, fail_fn);
  }
}

static void WaitUntilDirReady(const std::string& target, fail_fn_t fail_fn) {
  unsigned int sleepIntervalUs = STORAGE_DIR_CHECK_INIT_INTERVAL_US;

  // This is just an approximate value as it doesn't need to be very accurate.
  unsigned int sleepTotalUs = 0;

  const char* dir_path = target.c_str();
  while (sleepTotalUs < STORAGE_DIR_CHECK_TIMEOUT_US) {
    if (access(dir_path, F_OK) == 0) {
      return;
    }
    // Failed, so we add exponential backoff and retry
    usleep(sleepIntervalUs);
    sleepTotalUs += sleepIntervalUs;
    sleepIntervalUs = std::min<unsigned int>(
        sleepIntervalUs * STORAGE_DIR_CHECK_RETRY_MULTIPLIER,
        STORAGE_DIR_CHECK_MAX_INTERVAL_US);
  }
  // Last chance and get the latest errno if it fails.
  if (access(dir_path, F_OK) == 0) {
    return;
  }
  fail_fn(CREATE_ERROR("Error dir is not ready %s: %s", dir_path, strerror(errno)));
}

static void BindMountStorageToLowerFs(const userid_t user_id, const uid_t uid,
    const char* dir_name, const char* package, fail_fn_t fail_fn) {
    bool hasSdcardFs = IsSdcardfsUsed();
    std::string source;
    if (hasSdcardFs) {
        source = StringPrintf("/mnt/runtime/default/emulated/%d/%s/%s", user_id, dir_name, package);
    } else {
        source = StringPrintf("/mnt/pass_through/%d/emulated/%d/%s/%s", user_id, user_id, dir_name,
                              package);
    }

  // Directory might be not ready, as prepareStorageDirs() is running asynchronously in ProcessList,
  // so wait until dir is created.
  WaitUntilDirReady(source, fail_fn);
  std::string target = StringPrintf("/storage/emulated/%d/%s/%s", user_id, dir_name, package);

  // As the parent is mounted as tmpfs, we need to create the target dir here.
  PrepareDirIfNotPresent(target, 0700, uid, uid, fail_fn);

  if (access(source.c_str(), F_OK) != 0) {
    fail_fn(CREATE_ERROR("Error accessing %s: %s", source.c_str(), strerror(errno)));
  }
  if (access(target.c_str(), F_OK) != 0) {
    fail_fn(CREATE_ERROR("Error accessing %s: %s", target.c_str(), strerror(errno)));
  }
  BindMount(source, target, fail_fn);
}

// Mount tmpfs on Android/data and Android/obb, then bind mount all app visible package
// directories in data and obb directories.
static void BindMountStorageDirs(JNIEnv* env, jobjectArray pkg_data_info_list,
    uid_t uid, const char* process_name, jstring managed_nice_name, fail_fn_t fail_fn) {

  auto extract_fn = std::bind(ExtractJString, env, process_name, managed_nice_name, _1);
  const userid_t user_id = multiuser_get_user_id(uid);

  // Fuse is ready, so we can start using fuse path.
  int size = (pkg_data_info_list != nullptr) ? env->GetArrayLength(pkg_data_info_list) : 0;

  // Create tmpfs on Android/obb and Android/data so these 2 dirs won't enter fuse anymore.
  std::string androidObbDir = StringPrintf("/storage/emulated/%d/Android/obb", user_id);
  MountAppDataTmpFs(androidObbDir, fail_fn);
  std::string androidDataDir = StringPrintf("/storage/emulated/%d/Android/data", user_id);
  MountAppDataTmpFs(androidDataDir, fail_fn);

  // Bind mount each package obb directory
  for (int i = 0; i < size; i += 3) {
    jstring package_str = (jstring) (env->GetObjectArrayElement(pkg_data_info_list, i));
    std::string packageName = extract_fn(package_str).value();
    BindMountStorageToLowerFs(user_id, uid, "Android/obb", packageName.c_str(), fail_fn);
    BindMountStorageToLowerFs(user_id, uid, "Android/data", packageName.c_str(), fail_fn);
  }
}

// Utility routine to specialize a zygote child process.
static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids, jint runtime_flags,
                             jobjectArray rlimits, jlong permitted_capabilities,
                             jlong effective_capabilities, jint mount_external,
                             jstring managed_se_info, jstring managed_nice_name,
                             bool is_system_server, bool is_child_zygote,
                             jstring managed_instruction_set, jstring managed_app_data_dir,
                             bool is_top_app, jobjectArray pkg_data_info_list,
                             jobjectArray allowlisted_data_info_list, bool mount_data_dirs,
                             bool mount_storage_dirs) {
    const char* process_name = is_system_server ? "system_server" : "zygote";
    auto fail_fn = std::bind(ZygoteFailure, env, process_name, managed_nice_name, _1);
    auto extract_fn = std::bind(ExtractJString, env, process_name, managed_nice_name, _1);

    auto se_info = extract_fn(managed_se_info);
    auto nice_name = extract_fn(managed_nice_name);
    auto instruction_set = extract_fn(managed_instruction_set);
    auto app_data_dir = extract_fn(managed_app_data_dir);

    // Keep capabilities across UID change, unless we're staying root.
    if (uid != 0) {
        EnableKeepCapabilities(fail_fn);
    }

    SetInheritable(permitted_capabilities, fail_fn);

    DropCapabilitiesBoundingSet(fail_fn);

    bool need_pre_initialize_native_bridge = !is_system_server && instruction_set.has_value() &&
            android::NativeBridgeAvailable() &&
            // Native bridge may be already initialized if this
            // is an app forked from app-zygote.
            !android::NativeBridgeInitialized() &&
            android::NeedsNativeBridge(instruction_set.value().c_str());

    MountEmulatedStorage(uid, mount_external, need_pre_initialize_native_bridge, fail_fn);

    // Make sure app is running in its own mount namespace before isolating its data directories.
    ensureInAppMountNamespace(fail_fn);

    // Isolate app data, jit profile and sandbox data directories by overlaying a tmpfs on those
    // dirs and bind mount all related packages separately.
    if (mount_data_dirs) {
        // Sdk sandbox data isolation does not need to occur for app processes since sepolicy
        // prevents access to sandbox data anyway.
        if (is_sdk_sandbox_uid(uid)) {
            isolateSdkSandboxData(env, pkg_data_info_list, uid, process_name, managed_nice_name,
                                  fail_fn);
        }
        isolateAppData(env, pkg_data_info_list, allowlisted_data_info_list, uid, process_name,
                       managed_nice_name, fail_fn);
        isolateJitProfile(env, pkg_data_info_list, uid, process_name, managed_nice_name, fail_fn);
    }
    // MOUNT_EXTERNAL_INSTALLER, MOUNT_EXTERNAL_PASS_THROUGH, MOUNT_EXTERNAL_ANDROID_WRITABLE apps
    // will have mount_storage_dirs == false here (set by ProcessList.needsStorageDataIsolation()),
    // and hence they won't bind mount storage dirs.
    if (mount_storage_dirs) {
        BindMountStorageDirs(env, pkg_data_info_list, uid, process_name, managed_nice_name,
                             fail_fn);
    }

    // If this zygote isn't root, it won't be able to create a process group,
    // since the directory is owned by root.
    if (!is_system_server && getuid() == 0) {
        const int rc = createProcessGroup(uid, getpid());
        if (rc == -EROFS) {
            ALOGW("createProcessGroup failed, kernel missing CONFIG_CGROUP_CPUACCT?");
        } else if (rc != 0) {
            ALOGE("createProcessGroup(%d, %d) failed: %s", uid, /* pid= */ 0, strerror(-rc));
        }
    }

    SetGids(env, gids, is_child_zygote, fail_fn);
    SetRLimits(env, rlimits, fail_fn);

    if (need_pre_initialize_native_bridge) {
        // Due to the logic behind need_pre_initialize_native_bridge we know that
        // instruction_set contains a value.
        android::PreInitializeNativeBridge(app_data_dir.has_value() ? app_data_dir.value().c_str()
                                                                    : nullptr,
                                           instruction_set.value().c_str());
    }

    if (is_system_server) {
        // Prefetch the classloader for the system server. This is done early to
        // allow a tie-down of the proper system server selinux domain.
        env->CallStaticObjectMethod(gZygoteInitClass, gGetOrCreateSystemServerClassLoader);
        if (env->ExceptionCheck()) {
            // Be robust here. The Java code will attempt to create the classloader
            // at a later point (but may not have rights to use AoT artifacts).
            env->ExceptionClear();
        }
        // Also prefetch standalone system server jars. The reason for doing this here is the same
        // as above.
        env->CallStaticVoidMethod(gZygoteInitClass, gPrefetchStandaloneSystemServerJars);
        if (env->ExceptionCheck()) {
            env->ExceptionClear();
        }
    }

    if (setresgid(gid, gid, gid) == -1) {
        fail_fn(CREATE_ERROR("setresgid(%d) failed: %s", gid, strerror(errno)));
    }

    // Must be called when the new process still has CAP_SYS_ADMIN, in this case,
    // before changing uid from 0, which clears capabilities.  The other
    // alternative is to call prctl(PR_SET_NO_NEW_PRIVS, 1) afterward, but that
    // breaks SELinux domain transition (see b/71859146).  As the result,
    // privileged syscalls used below still need to be accessible in app process.
    SetUpSeccompFilter(uid, is_child_zygote);

    // Must be called before losing the permission to set scheduler policy.
    SetSchedulerPolicy(fail_fn, is_top_app);

    if (setresuid(uid, uid, uid) == -1) {
        fail_fn(CREATE_ERROR("setresuid(%d) failed: %s", uid, strerror(errno)));
    }

    // The "dumpable" flag of a process, which controls core dump generation, is
    // overwritten by the value in /proc/sys/fs/suid_dumpable when the effective
    // user or group ID changes. See proc(5) for possible values. In most cases,
    // the value is 0, so core dumps are disabled for zygote children. However,
    // when running in a Chrome OS container, the value is already set to 2,
    // which allows the external crash reporter to collect all core dumps. Since
    // only system crashes are interested, core dump is disabled for app
    // processes. This also ensures compliance with CTS.
    int dumpable = prctl(PR_GET_DUMPABLE);
    if (dumpable == -1) {
        ALOGE("prctl(PR_GET_DUMPABLE) failed: %s", strerror(errno));
        RuntimeAbort(env, __LINE__, "prctl(PR_GET_DUMPABLE) failed");
    }

    if (dumpable == 2 && uid >= AID_APP) {
        if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0) == -1) {
            ALOGE("prctl(PR_SET_DUMPABLE, 0) failed: %s", strerror(errno));
            RuntimeAbort(env, __LINE__, "prctl(PR_SET_DUMPABLE, 0) failed");
        }
    }

    // Set process properties to enable debugging if required.
    if ((runtime_flags & RuntimeFlags::DEBUG_ENABLE_JDWP) != 0) {
        EnableDebugger();
    }
    if ((runtime_flags & RuntimeFlags::PROFILE_FROM_SHELL) != 0) {
        // simpleperf needs the process to be dumpable to profile it.
        if (prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) == -1) {
            ALOGE("prctl(PR_SET_DUMPABLE) failed: %s", strerror(errno));
            RuntimeAbort(env, __LINE__, "prctl(PR_SET_DUMPABLE, 1) failed");
        }
    }

    HeapTaggingLevel heap_tagging_level;
    switch (runtime_flags & RuntimeFlags::MEMORY_TAG_LEVEL_MASK) {
        case RuntimeFlags::MEMORY_TAG_LEVEL_TBI:
            heap_tagging_level = M_HEAP_TAGGING_LEVEL_TBI;
            break;
        case RuntimeFlags::MEMORY_TAG_LEVEL_ASYNC:
            heap_tagging_level = M_HEAP_TAGGING_LEVEL_ASYNC;
            break;
        case RuntimeFlags::MEMORY_TAG_LEVEL_SYNC:
            heap_tagging_level = M_HEAP_TAGGING_LEVEL_SYNC;
            break;
        default:
            heap_tagging_level = M_HEAP_TAGGING_LEVEL_NONE;
            break;
    }
    mallopt(M_BIONIC_SET_HEAP_TAGGING_LEVEL, heap_tagging_level);

    // Now that we've used the flag, clear it so that we don't pass unknown flags to the ART
    // runtime.
    runtime_flags &= ~RuntimeFlags::MEMORY_TAG_LEVEL_MASK;

    // Avoid heap zero initialization for applications without MTE. Zero init may
    // cause app compat problems, use more memory, or reduce performance. While it
    // would be nice to have them for apps, we will have to wait until they are
    // proven out, have more efficient hardware, and/or apply them only to new
    // applications.
    if (!(runtime_flags & RuntimeFlags::NATIVE_HEAP_ZERO_INIT_ENABLED)) {
        mallopt(M_BIONIC_ZERO_INIT, 0);
    }

    // Now that we've used the flag, clear it so that we don't pass unknown flags to the ART
    // runtime.
    runtime_flags &= ~RuntimeFlags::NATIVE_HEAP_ZERO_INIT_ENABLED;

    const char* nice_name_ptr = nice_name.has_value() ? nice_name.value().c_str() : nullptr;
    android_mallopt_gwp_asan_options_t gwp_asan_options;
    // The system server doesn't have its nice name set by the time SpecializeCommon is called.
    gwp_asan_options.program_name = nice_name_ptr ?: process_name;
    switch (runtime_flags & RuntimeFlags::GWP_ASAN_LEVEL_MASK) {
        default:
        case RuntimeFlags::GWP_ASAN_LEVEL_NEVER:
            gwp_asan_options.desire = Action::DONT_TURN_ON_UNLESS_OVERRIDDEN;
            android_mallopt(M_INITIALIZE_GWP_ASAN, &gwp_asan_options, sizeof(gwp_asan_options));
            break;
        case RuntimeFlags::GWP_ASAN_LEVEL_ALWAYS:
            gwp_asan_options.desire = Action::TURN_ON_FOR_APP;
            android_mallopt(M_INITIALIZE_GWP_ASAN, &gwp_asan_options, sizeof(gwp_asan_options));
            break;
        case RuntimeFlags::GWP_ASAN_LEVEL_LOTTERY:
            gwp_asan_options.desire = Action::TURN_ON_WITH_SAMPLING;
            android_mallopt(M_INITIALIZE_GWP_ASAN, &gwp_asan_options, sizeof(gwp_asan_options));
            break;
    }
    // Now that we've used the flag, clear it so that we don't pass unknown flags to the ART
    // runtime.
    runtime_flags &= ~RuntimeFlags::GWP_ASAN_LEVEL_MASK;

    SetCapabilities(permitted_capabilities, effective_capabilities, permitted_capabilities,
                    fail_fn);

    __android_log_close();
    AStatsSocket_close();

    const char* se_info_ptr = se_info.has_value() ? se_info.value().c_str() : nullptr;

    if (selinux_android_setcontext(uid, is_system_server, se_info_ptr, nice_name_ptr) == -1) {
        fail_fn(CREATE_ERROR("selinux_android_setcontext(%d, %d, \"%s\", \"%s\") failed", uid,
                             is_system_server, se_info_ptr, nice_name_ptr));
    }

    // Make it easier to debug audit logs by setting the main thread's name to the
    // nice name rather than "app_process".
    if (nice_name.has_value()) {
        SetThreadName(nice_name.value());
    } else if (is_system_server) {
        SetThreadName("system_server");
    }

    // Unset the SIGCHLD handler, but keep ignoring SIGHUP (rationale in SetSignalHandlers).
    UnsetChldSignalHandler();

    if (is_system_server) {
        env->CallStaticVoidMethod(gZygoteClass, gCallPostForkSystemServerHooks, runtime_flags);
        if (env->ExceptionCheck()) {
            fail_fn("Error calling post fork system server hooks.");
        }

        // TODO(b/117874058): Remove hardcoded label here.
        static const char* kSystemServerLabel = "u:r:system_server:s0";
        if (selinux_android_setcon(kSystemServerLabel) != 0) {
            fail_fn(CREATE_ERROR("selinux_android_setcon(%s)", kSystemServerLabel));
        }
    }

    if (is_child_zygote) {
        initUnsolSocketToSystemServer();
    }

    env->CallStaticVoidMethod(gZygoteClass, gCallPostForkChildHooks, runtime_flags,
                              is_system_server, is_child_zygote, managed_instruction_set);

    // Reset the process priority to the default value.
    setpriority(PRIO_PROCESS, 0, PROCESS_PRIORITY_DEFAULT);

    if (env->ExceptionCheck()) {
        fail_fn("Error calling post fork hooks.");
    }
}

static uint64_t GetEffectiveCapabilityMask(JNIEnv* env) {
    __user_cap_header_struct capheader;
    memset(&capheader, 0, sizeof(capheader));
    capheader.version = _LINUX_CAPABILITY_VERSION_3;
    capheader.pid = 0;

    __user_cap_data_struct capdata[2];
    if (capget(&capheader, &capdata[0]) == -1) {
        ALOGE("capget failed: %s", strerror(errno));
        RuntimeAbort(env, __LINE__, "capget failed");
    }

    return capdata[0].effective | (static_cast<uint64_t>(capdata[1].effective) << 32);
}

static jlong CalculateCapabilities(JNIEnv* env, jint uid, jint gid, jintArray gids,
                                   bool is_child_zygote) {
  jlong capabilities = 0;

  /*
   *  Grant the following capabilities to the Bluetooth user:
   *    - CAP_WAKE_ALARM
   *    - CAP_NET_ADMIN
   *    - CAP_NET_RAW
   *    - CAP_NET_BIND_SERVICE (for DHCP client functionality)
   *    - CAP_SYS_NICE (for setting RT priority for audio-related threads)
   */

  if (multiuser_get_app_id(uid) == AID_BLUETOOTH) {
    capabilities |= (1LL << CAP_WAKE_ALARM);
    capabilities |= (1LL << CAP_NET_ADMIN);
    capabilities |= (1LL << CAP_NET_RAW);
    capabilities |= (1LL << CAP_NET_BIND_SERVICE);
    capabilities |= (1LL << CAP_SYS_NICE);
  }

  if (multiuser_get_app_id(uid) == AID_NETWORK_STACK) {
    capabilities |= (1LL << CAP_NET_ADMIN);
    capabilities |= (1LL << CAP_NET_BROADCAST);
    capabilities |= (1LL << CAP_NET_BIND_SERVICE);
    capabilities |= (1LL << CAP_NET_RAW);
  }

  /*
   * Grant CAP_BLOCK_SUSPEND to processes that belong to GID "wakelock"
   */

  bool gid_wakelock_found = false;
  if (gid == AID_WAKELOCK) {
    gid_wakelock_found = true;
  } else if (gids != nullptr) {
    jsize gids_num = env->GetArrayLength(gids);
    ScopedIntArrayRO native_gid_proxy(env, gids);

    if (native_gid_proxy.get() == nullptr) {
      RuntimeAbort(env, __LINE__, "Bad gids array");
    }

    for (int gids_index = 0; gids_index < gids_num; ++gids_index) {
      if (native_gid_proxy[gids_index] == AID_WAKELOCK) {
        gid_wakelock_found = true;
        break;
      }
    }
  }

  if (gid_wakelock_found) {
    capabilities |= (1LL << CAP_BLOCK_SUSPEND);
  }

  /*
   * Grant child Zygote processes the following capabilities:
   *   - CAP_SETUID (change UID of child processes)
   *   - CAP_SETGID (change GID of child processes)
   *   - CAP_SETPCAP (change capabilities of child processes)
   */

  if (is_child_zygote) {
    capabilities |= (1LL << CAP_SETUID);
    capabilities |= (1LL << CAP_SETGID);
    capabilities |= (1LL << CAP_SETPCAP);
  }

  /*
   * Containers run without some capabilities, so drop any caps that are not
   * available.
   */

  return capabilities & GetEffectiveCapabilityMask(env);
}

/**
 * Adds the given information about a newly created unspecialized app
 * processes to the Zygote's USAP table.
 *
 * @param usap_pid  Process ID of the newly created USAP
 * @param read_pipe_fd  File descriptor for the read end of the USAP
 * reporting pipe.  Used in the ZygoteServer poll loop to track USAP
 * specialization.
 */
static void AddUsapTableEntry(pid_t usap_pid, int read_pipe_fd) {
  static int sUsapTableInsertIndex = 0;

  int search_index = sUsapTableInsertIndex;
  do {
    if (gUsapTable[search_index].SetIfInvalid(usap_pid, read_pipe_fd)) {
      ++gUsapPoolCount;

      // Start our next search right after where we finished this one.
      sUsapTableInsertIndex = (search_index + 1) % gUsapTable.size();

      return;
    }

    search_index = (search_index + 1) % gUsapTable.size();
  } while (search_index != sUsapTableInsertIndex);

  // Much like money in the banana stand, there should always be an entry
  // in the USAP table.
  __builtin_unreachable();
}

/**
 * Invalidates the entry in the USAPTable corresponding to the provided
 * process ID if it is present.  If an entry was removed the USAP pool
 * count is decremented. May be called from signal handler.
 *
 * @param usap_pid  Process ID of the USAP entry to invalidate
 * @return True if an entry was invalidated; false otherwise
 */
static bool RemoveUsapTableEntry(pid_t usap_pid) {
  for (UsapTableEntry& entry : gUsapTable) {
    if (entry.ClearForPID(usap_pid)) {
      --gUsapPoolCount;
      return true;
    }
  }

  return false;
}

/**
 * @return A vector of the read pipe FDs for each of the active USAPs.
 */
std::vector<int> MakeUsapPipeReadFDVector() {
  std::vector<int> fd_vec;
  fd_vec.reserve(gUsapTable.size());

  for (UsapTableEntry& entry : gUsapTable) {
    auto entry_values = entry.GetValues();

    if (entry_values.has_value()) {
      fd_vec.push_back(entry_values.value().read_pipe_fd);
    }
  }

  return fd_vec;
}

static void UnmountStorageOnInit(JNIEnv* env) {
  // Zygote process unmount root storage space initially before every child processes are forked.
  // Every forked child processes (include SystemServer) only mount their own root storage space
  // and no need unmount storage operation in MountEmulatedStorage method.
  // Zygote process does not utilize root storage spaces and unshares its mount namespace below.

  // See storage config details at http://source.android.com/tech/storage/
  // Create private mount namespace shared by all children
  if (unshare(CLONE_NEWNS) == -1) {
    RuntimeAbort(env, __LINE__, "Failed to unshare()");
    return;
  }

  // Mark rootfs as being MS_SLAVE so that changes from default
  // namespace only flow into our children.
  if (mount("rootfs", "/", nullptr, (MS_SLAVE | MS_REC), nullptr) == -1) {
    RuntimeAbort(env, __LINE__, "Failed to mount() rootfs as MS_SLAVE");
    return;
  }

  // Create a staging tmpfs that is shared by our children; they will
  // bind mount storage into their respective private namespaces, which
  // are isolated from each other.
  const char* target_base = getenv("EMULATED_STORAGE_TARGET");
  if (target_base != nullptr) {
#define STRINGIFY_UID(x) __STRING(x)
    if (mount("tmpfs", target_base, "tmpfs", MS_NOSUID | MS_NODEV,
              "uid=0,gid=" STRINGIFY_UID(AID_SDCARD_R) ",mode=0751") == -1) {
      ALOGE("Failed to mount tmpfs to %s", target_base);
      RuntimeAbort(env, __LINE__, "Failed to mount tmpfs");
      return;
    }
#undef STRINGIFY_UID
  }

  UnmountTree("/storage");
}

}  // anonymous namespace

namespace android {

/**
 * A failure function used to report fatal errors to the managed runtime.  This
 * function is often curried with the process name information and then passed
 * to called functions.
 *
 * @param env  Managed runtime environment
 * @param process_name  A native representation of the process name
 * @param managed_process_name  A managed representation of the process name
 * @param msg  The error message to be reported
 */
[[noreturn]]
void zygote::ZygoteFailure(JNIEnv* env,
                           const char* process_name,
                           jstring managed_process_name,
                           const std::string& msg) {
  std::unique_ptr<ScopedUtfChars> scoped_managed_process_name_ptr = nullptr;
  if (managed_process_name != nullptr) {
    scoped_managed_process_name_ptr.reset(new ScopedUtfChars(env, managed_process_name));
    if (scoped_managed_process_name_ptr->c_str() != nullptr) {
      process_name = scoped_managed_process_name_ptr->c_str();
    }
  }

  const std::string& error_msg =
      (process_name == nullptr || process_name[0] == '\0') ?
      msg : StringPrintf("(%s) %s", process_name, msg.c_str());

  env->FatalError(error_msg.c_str());
  __builtin_unreachable();
}

static std::set<int>* gPreloadFds = nullptr;
static bool gPreloadFdsExtracted = false;

// Utility routine to fork a process from the zygote.
pid_t zygote::ForkCommon(JNIEnv* env, bool is_system_server,
                         const std::vector<int>& fds_to_close,
                         const std::vector<int>& fds_to_ignore,
                         bool is_priority_fork,
                         bool purge) {
  SetSignalHandlers();

  // Curry a failure function.
  auto fail_fn = std::bind(zygote::ZygoteFailure, env,
                           is_system_server ? "system_server" : "zygote",
                           nullptr, _1);

  // Temporarily block SIGCHLD during forks. The SIGCHLD handler might
  // log, which would result in the logging FDs we close being reopened.
  // This would cause failures because the FDs are not allowlisted.
  //
  // Note that the zygote process is single threaded at this point.
  BlockSignal(SIGCHLD, fail_fn);

  // Close any logging related FDs before we start evaluating the list of
  // file descriptors.
  __android_log_close();
  AStatsSocket_close();

  // If this is the first fork for this zygote, create the open FD table,
  // verifying that files are of supported type and allowlisted.  Otherwise (not
  // the first fork), check that the open files have not changed.  Newly open
  // files are not expected, and will be disallowed in the future.  Currently
  // they are allowed if they pass the same checks as in the
  // FileDescriptorTable::Create() above.
  if (gOpenFdTable == nullptr) {
    gOpenFdTable = FileDescriptorTable::Create(fds_to_ignore, fail_fn);
  } else {
    gOpenFdTable->Restat(fds_to_ignore, fail_fn);
  }

  android_fdsan_error_level fdsan_error_level = android_fdsan_get_error_level();

  if (purge) {
    // Purge unused native memory in an attempt to reduce the amount of false
    // sharing with the child process.  By reducing the size of the libc_malloc
    // region shared with the child process we reduce the number of pages that
    // transition to the private-dirty state when malloc adjusts the meta-data
    // on each of the pages it is managing after the fork.
    mallopt(M_PURGE, 0);
  }

  pid_t pid = fork();

  if (pid == 0) {
    if (is_priority_fork) {
      setpriority(PRIO_PROCESS, 0, PROCESS_PRIORITY_MAX);
    } else {
      setpriority(PRIO_PROCESS, 0, PROCESS_PRIORITY_MIN);
    }

    // The child process.
    PreApplicationInit();

    // Clean up any descriptors which must be closed immediately
    DetachDescriptors(env, fds_to_close, fail_fn);

    // Invalidate the entries in the USAP table.
    ClearUsapTable();

    // Re-open all remaining open file descriptors so that they aren't shared
    // with the zygote across a fork.
    gOpenFdTable->ReopenOrDetach(fail_fn);

    // Turn fdsan back on.
    android_fdsan_set_error_level(fdsan_error_level);

    // Reset the fd to the unsolicited zygote socket
    gSystemServerSocketFd = -1;
  } else {
    ALOGD("Forked child process %d", pid);
  }

  // We blocked SIGCHLD prior to a fork, we unblock it here.
  UnblockSignal(SIGCHLD, fail_fn);

  return pid;
}

static void com_android_internal_os_Zygote_nativePreApplicationInit(JNIEnv*, jclass) {
  PreApplicationInit();
}

static jint com_android_internal_os_Zygote_nativeForkAndSpecialize(
        JNIEnv* env, jclass, jint uid, jint gid, jintArray gids, jint runtime_flags,
        jobjectArray rlimits, jint mount_external, jstring se_info, jstring nice_name,
        jintArray managed_fds_to_close, jintArray managed_fds_to_ignore, jboolean is_child_zygote,
        jstring instruction_set, jstring app_data_dir, jboolean is_top_app,
        jobjectArray pkg_data_info_list, jobjectArray allowlisted_data_info_list,
        jboolean mount_data_dirs, jboolean mount_storage_dirs) {
    jlong capabilities = CalculateCapabilities(env, uid, gid, gids, is_child_zygote);

    if (UNLIKELY(managed_fds_to_close == nullptr)) {
      zygote::ZygoteFailure(env, "zygote", nice_name,
                            "Zygote received a null fds_to_close vector.");
    }

    std::vector<int> fds_to_close =
        ExtractJIntArray(env, "zygote", nice_name, managed_fds_to_close).value();
    std::vector<int> fds_to_ignore =
        ExtractJIntArray(env, "zygote", nice_name, managed_fds_to_ignore)
            .value_or(std::vector<int>());

    std::vector<int> usap_pipes = MakeUsapPipeReadFDVector();

    fds_to_close.insert(fds_to_close.end(), usap_pipes.begin(), usap_pipes.end());
    fds_to_ignore.insert(fds_to_ignore.end(), usap_pipes.begin(), usap_pipes.end());

    fds_to_close.push_back(gUsapPoolSocketFD);

    if (gUsapPoolEventFD != -1) {
      fds_to_close.push_back(gUsapPoolEventFD);
      fds_to_ignore.push_back(gUsapPoolEventFD);
    }

    if (gSystemServerSocketFd != -1) {
        fds_to_close.push_back(gSystemServerSocketFd);
        fds_to_ignore.push_back(gSystemServerSocketFd);
    }

    if (gPreloadFds && gPreloadFdsExtracted) {
        fds_to_ignore.insert(fds_to_ignore.end(), gPreloadFds->begin(), gPreloadFds->end());
    }

    pid_t pid = zygote::ForkCommon(env, /* is_system_server= */ false, fds_to_close, fds_to_ignore,
                                   true);

    if (pid == 0) {
        SpecializeCommon(env, uid, gid, gids, runtime_flags, rlimits, capabilities, capabilities,
                         mount_external, se_info, nice_name, false, is_child_zygote == JNI_TRUE,
                         instruction_set, app_data_dir, is_top_app == JNI_TRUE, pkg_data_info_list,
                         allowlisted_data_info_list, mount_data_dirs == JNI_TRUE,
                         mount_storage_dirs == JNI_TRUE);
    }
    return pid;
}

static jint com_android_internal_os_Zygote_nativeForkSystemServer(
        JNIEnv* env, jclass, uid_t uid, gid_t gid, jintArray gids,
        jint runtime_flags, jobjectArray rlimits, jlong permitted_capabilities,
        jlong effective_capabilities) {
  std::vector<int> fds_to_close(MakeUsapPipeReadFDVector()),
                   fds_to_ignore(fds_to_close);

  fds_to_close.push_back(gUsapPoolSocketFD);

  if (gUsapPoolEventFD != -1) {
    fds_to_close.push_back(gUsapPoolEventFD);
    fds_to_ignore.push_back(gUsapPoolEventFD);
  }

  if (gSystemServerSocketFd != -1) {
      fds_to_close.push_back(gSystemServerSocketFd);
      fds_to_ignore.push_back(gSystemServerSocketFd);
  }

  pid_t pid = zygote::ForkCommon(env, true,
                                 fds_to_close,
                                 fds_to_ignore,
                                 true);
  if (pid == 0) {
      // System server prcoess does not need data isolation so no need to
      // know pkg_data_info_list.
      SpecializeCommon(env, uid, gid, gids, runtime_flags, rlimits, permitted_capabilities,
                       effective_capabilities, MOUNT_EXTERNAL_DEFAULT, nullptr, nullptr, true,
                       false, nullptr, nullptr, /* is_top_app= */ false,
                       /* pkg_data_info_list */ nullptr,
                       /* allowlisted_data_info_list */ nullptr, false, false);
  } else if (pid > 0) {
      // The zygote process checks whether the child process has died or not.
      ALOGI("System server process %d has been created", pid);
      gSystemServerPid = pid;
      // There is a slight window that the system server process has crashed
      // but it went unnoticed because we haven't published its pid yet. So
      // we recheck here just to make sure that all is well.
      int status;
      if (waitpid(pid, &status, WNOHANG) == pid) {
          ALOGE("System server process %d has died. Restarting Zygote!", pid);
          RuntimeAbort(env, __LINE__, "System server process has died. Restarting Zygote!");
      }

      if (UsePerAppMemcg()) {
          // Assign system_server to the correct memory cgroup.
          // Not all devices mount memcg so check if it is mounted first
          // to avoid unnecessarily printing errors and denials in the logs.
          if (!SetTaskProfiles(pid, std::vector<std::string>{"SystemMemoryProcess"})) {
              ALOGE("couldn't add process %d into system memcg group", pid);
          }
      }
  }
  return pid;
}

/**
 * A JNI function that forks an unspecialized app process from the Zygote while
 * ensuring proper file descriptor hygiene.
 *
 * @param env  Managed runtime environment
 * @param read_pipe_fd  The read FD for the USAP reporting pipe.  Manually closed by the child
 * in managed code. -1 indicates none.
 * @param write_pipe_fd  The write FD for the USAP reporting pipe.  Manually closed by the
 * zygote in managed code. -1 indicates none.
 * @param managed_session_socket_fds  A list of anonymous session sockets that must be ignored by
 * the FD hygiene code and automatically "closed" in the new USAP.
 * @param args_known Arguments for specialization are available; no need to read from a socket
 * @param is_priority_fork  Controls the nice level assigned to the newly created process
 * @return child pid in the parent, 0 in the child
 */
static jint com_android_internal_os_Zygote_nativeForkApp(JNIEnv* env,
                                                         jclass,
                                                         jint read_pipe_fd,
                                                         jint write_pipe_fd,
                                                         jintArray managed_session_socket_fds,
                                                         jboolean args_known,
                                                         jboolean is_priority_fork) {
  std::vector<int> session_socket_fds =
      ExtractJIntArray(env, "USAP", nullptr, managed_session_socket_fds)
          .value_or(std::vector<int>());
  return zygote::forkApp(env, read_pipe_fd, write_pipe_fd, session_socket_fds,
                            args_known == JNI_TRUE, is_priority_fork == JNI_TRUE, true);
}

int zygote::forkApp(JNIEnv* env,
                    int read_pipe_fd,
                    int write_pipe_fd,
                    const std::vector<int>& session_socket_fds,
                    bool args_known,
                    bool is_priority_fork,
                    bool purge) {

  std::vector<int> fds_to_close(MakeUsapPipeReadFDVector()),
                   fds_to_ignore(fds_to_close);

  fds_to_close.push_back(gZygoteSocketFD);
  if (gSystemServerSocketFd != -1) {
      fds_to_close.push_back(gSystemServerSocketFd);
  }
  if (args_known) {
      fds_to_close.push_back(gUsapPoolSocketFD);
  }
  fds_to_close.insert(fds_to_close.end(), session_socket_fds.begin(), session_socket_fds.end());

  fds_to_ignore.push_back(gUsapPoolSocketFD);
  fds_to_ignore.push_back(gZygoteSocketFD);
  if (read_pipe_fd != -1) {
      fds_to_ignore.push_back(read_pipe_fd);
  }
  if (write_pipe_fd != -1) {
      fds_to_ignore.push_back(write_pipe_fd);
  }
  fds_to_ignore.insert(fds_to_ignore.end(), session_socket_fds.begin(), session_socket_fds.end());

  if (gUsapPoolEventFD != -1) {
      fds_to_close.push_back(gUsapPoolEventFD);
      fds_to_ignore.push_back(gUsapPoolEventFD);
  }
  if (gSystemServerSocketFd != -1) {
      if (args_known) {
          fds_to_close.push_back(gSystemServerSocketFd);
      }
      fds_to_ignore.push_back(gSystemServerSocketFd);
  }
  if (gPreloadFds && gPreloadFdsExtracted) {
      fds_to_ignore.insert(fds_to_ignore.end(), gPreloadFds->begin(), gPreloadFds->end());
  }

  return zygote::ForkCommon(env, /* is_system_server= */ false, fds_to_close,
                            fds_to_ignore, is_priority_fork == JNI_TRUE, purge);
}

static void com_android_internal_os_Zygote_nativeAllowFileAcrossFork(
        JNIEnv* env, jclass, jstring path) {
    ScopedUtfChars path_native(env, path);
    const char* path_cstr = path_native.c_str();
    if (!path_cstr) {
        RuntimeAbort(env, __LINE__, "path_cstr == nullptr");
    }
    FileDescriptorAllowlist::Get()->Allow(path_cstr);
}

static void com_android_internal_os_Zygote_nativeInstallSeccompUidGidFilter(
        JNIEnv* env, jclass, jint uidGidMin, jint uidGidMax) {
  if (!gIsSecurityEnforced) {
    ALOGI("seccomp disabled by setenforce 0");
    return;
  }

  bool installed = install_setuidgid_seccomp_filter(uidGidMin, uidGidMax);
  if (!installed) {
      RuntimeAbort(env, __LINE__, "Could not install setuid/setgid seccomp filter.");
  }
}

/**
 * Called from an unspecialized app process to specialize the process for a
 * given application.
 *
 * @param env  Managed runtime environment
 * @param uid  User ID of the new application
 * @param gid  Group ID of the new application
 * @param gids  Extra groups that the process belongs to
 * @param runtime_flags  Flags for changing the behavior of the managed runtime
 * @param rlimits  Resource limits
 * @param mount_external  The mode (read/write/normal) that external storage will be mounted with
 * @param se_info  SELinux policy information
 * @param nice_name  New name for this process
 * @param is_child_zygote  If the process is to become a WebViewZygote
 * @param instruction_set  The instruction set expected/requested by the new application
 * @param app_data_dir  Path to the application's data directory
 * @param is_top_app  If the process is for top (high priority) application
 */
static void com_android_internal_os_Zygote_nativeSpecializeAppProcess(
        JNIEnv* env, jclass, jint uid, jint gid, jintArray gids, jint runtime_flags,
        jobjectArray rlimits, jint mount_external, jstring se_info, jstring nice_name,
        jboolean is_child_zygote, jstring instruction_set, jstring app_data_dir,
        jboolean is_top_app, jobjectArray pkg_data_info_list,
        jobjectArray allowlisted_data_info_list, jboolean mount_data_dirs,
        jboolean mount_storage_dirs) {
    jlong capabilities = CalculateCapabilities(env, uid, gid, gids, is_child_zygote);

    SpecializeCommon(env, uid, gid, gids, runtime_flags, rlimits, capabilities, capabilities,
                     mount_external, se_info, nice_name, false, is_child_zygote == JNI_TRUE,
                     instruction_set, app_data_dir, is_top_app == JNI_TRUE, pkg_data_info_list,
                     allowlisted_data_info_list, mount_data_dirs == JNI_TRUE,
                     mount_storage_dirs == JNI_TRUE);
}

/**
 * A helper method for fetching socket file descriptors that were opened by init from the
 * environment.
 *
 * @param env  Managed runtime environment
 * @param is_primary  If this process is the primary or secondary Zygote; used to compute the name
 * of the environment variable storing the file descriptors.
 */
static void com_android_internal_os_Zygote_nativeInitNativeState(JNIEnv* env, jclass,
                                                                 jboolean is_primary) {
  /*
   * Obtain file descriptors created by init from the environment.
   */

  gZygoteSocketFD =
      android_get_control_socket(is_primary ? "zygote" : "zygote_secondary");
  if (gZygoteSocketFD >= 0) {
    ALOGV("Zygote:zygoteSocketFD = %d", gZygoteSocketFD);
  } else {
    ALOGE("Unable to fetch Zygote socket file descriptor");
  }

  gUsapPoolSocketFD =
      android_get_control_socket(is_primary ? "usap_pool_primary" : "usap_pool_secondary");
  if (gUsapPoolSocketFD >= 0) {
    ALOGV("Zygote:usapPoolSocketFD = %d", gUsapPoolSocketFD);
  } else {
    ALOGE("Unable to fetch USAP pool socket file descriptor");
  }

  initUnsolSocketToSystemServer();

  /*
   * Security Initialization
   */

  // security_getenforce is not allowed on app process. Initialize and cache
  // the value before zygote forks.
  gIsSecurityEnforced = security_getenforce();

  selinux_android_seapp_context_init();

  /*
   * Storage Initialization
   */

  UnmountStorageOnInit(env);

  /*
   * Performance Initialization
   */

  if (!SetTaskProfiles(0, {})) {
    zygote::ZygoteFailure(env, "zygote", nullptr, "Zygote SetTaskProfiles failed");
  }
}

/**
 * @param env  Managed runtime environment
 * @return  A managed array of raw file descriptors for the read ends of the USAP reporting
 * pipes.
 */
static jintArray com_android_internal_os_Zygote_nativeGetUsapPipeFDs(JNIEnv* env, jclass) {
  std::vector<int> usap_fds = MakeUsapPipeReadFDVector();

  jintArray managed_usap_fds = env->NewIntArray(usap_fds.size());
  env->SetIntArrayRegion(managed_usap_fds, 0, usap_fds.size(), usap_fds.data());

  return managed_usap_fds;
}

/*
 * Add the given pid and file descriptor to the Usap table. CriticalNative method.
 */
static void com_android_internal_os_Zygote_nativeAddUsapTableEntry(jint pid, jint read_pipe_fd) {
  AddUsapTableEntry(pid, read_pipe_fd);
}

/**
 * A JNI wrapper around RemoveUsapTableEntry. CriticalNative method.
 *
 * @param env  Managed runtime environment
 * @param usap_pid  Process ID of the USAP entry to invalidate
 * @return  True if an entry was invalidated; false otherwise.
 */
static jboolean com_android_internal_os_Zygote_nativeRemoveUsapTableEntry(jint usap_pid) {
  return RemoveUsapTableEntry(usap_pid);
}

/**
 * Creates the USAP pool event FD if it doesn't exist and returns it.  This is used by the
 * ZygoteServer poll loop to know when to re-fill the USAP pool.
 *
 * @param env  Managed runtime environment
 * @return A raw event file descriptor used to communicate (from the signal handler) when the
 * Zygote receives a SIGCHLD for a USAP
 */
static jint com_android_internal_os_Zygote_nativeGetUsapPoolEventFD(JNIEnv* env, jclass) {
  if (gUsapPoolEventFD == -1) {
    if ((gUsapPoolEventFD = eventfd(0, 0)) == -1) {
      zygote::ZygoteFailure(env, "zygote", nullptr,
                            StringPrintf("Unable to create eventfd: %s", strerror(errno)));
    }
  }

  return gUsapPoolEventFD;
}

/**
 * @param env  Managed runtime environment
 * @return The number of USAPs currently in the USAP pool
 */
static jint com_android_internal_os_Zygote_nativeGetUsapPoolCount(JNIEnv* env, jclass) {
  return gUsapPoolCount;
}

/**
 * Kills all processes currently in the USAP pool and closes their read pipe
 * FDs.
 *
 * @param env  Managed runtime environment
 */
static void com_android_internal_os_Zygote_nativeEmptyUsapPool(JNIEnv* env, jclass) {
  for (auto& entry : gUsapTable) {
    auto entry_storage = entry.GetValues();

    if (entry_storage.has_value()) {
      kill(entry_storage.value().pid, SIGTERM);

      // Clean up the USAP table entry here.  This avoids a potential race
      // where a newly created USAP might not be able to find a valid table
      // entry if signal handler (which would normally do the cleanup) doesn't
      // run between now and when the new process is created.

      close(entry_storage.value().read_pipe_fd);

      // Avoid a second atomic load by invalidating instead of clearing.
      entry.Invalidate();
      --gUsapPoolCount;
    }
  }
}

static void com_android_internal_os_Zygote_nativeBlockSigTerm(JNIEnv* env, jclass) {
  auto fail_fn = std::bind(zygote::ZygoteFailure, env, "usap", nullptr, _1);
  BlockSignal(SIGTERM, fail_fn);
}

static void com_android_internal_os_Zygote_nativeUnblockSigTerm(JNIEnv* env, jclass) {
  auto fail_fn = std::bind(zygote::ZygoteFailure, env, "usap", nullptr, _1);
  UnblockSignal(SIGTERM, fail_fn);
}

static void com_android_internal_os_Zygote_nativeBoostUsapPriority(JNIEnv* env, jclass) {
  setpriority(PRIO_PROCESS, 0, PROCESS_PRIORITY_MAX);
}

static jint com_android_internal_os_Zygote_nativeParseSigChld(JNIEnv* env, jclass, jbyteArray in,
                                                              jint length, jintArray out) {
    if (length != sizeof(struct UnsolicitedZygoteMessageSigChld)) {
        // Apparently it's not the message we are expecting.
        return -1;
    }
    if (in == nullptr || out == nullptr) {
        // Invalid parameter
        jniThrowException(env, "java/lang/IllegalArgumentException", nullptr);
        return -1;
    }
    ScopedByteArrayRO source(env, in);
    if (source.size() < length) {
        // Invalid parameter
        jniThrowException(env, "java/lang/IllegalArgumentException", nullptr);
        return -1;
    }
    const struct UnsolicitedZygoteMessageSigChld* msg =
            reinterpret_cast<const struct UnsolicitedZygoteMessageSigChld*>(source.get());

    switch (msg->header.type) {
        case UNSOLICITED_ZYGOTE_MESSAGE_TYPE_SIGCHLD: {
            ScopedIntArrayRW buf(env, out);
            if (buf.size() != 3) {
                jniThrowException(env, "java/lang/IllegalArgumentException", nullptr);
                return UNSOLICITED_ZYGOTE_MESSAGE_TYPE_RESERVED;
            }
            buf[0] = msg->payload.pid;
            buf[1] = msg->payload.uid;
            buf[2] = msg->payload.status;
            return 3;
        }
        default:
            break;
    }
    return -1;
}

static jboolean com_android_internal_os_Zygote_nativeSupportsMemoryTagging(JNIEnv* env, jclass) {
#if defined(__aarch64__)
  return mte_supported();
#else
  return false;
#endif
}

static jboolean com_android_internal_os_Zygote_nativeSupportsTaggedPointers(JNIEnv* env, jclass) {
#ifdef __aarch64__
  int res = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0);
  return res >= 0 && res & PR_TAGGED_ADDR_ENABLE;
#else
  return false;
#endif
}

static jint com_android_internal_os_Zygote_nativeCurrentTaggingLevel(JNIEnv* env, jclass) {
#if defined(__aarch64__)
  int level = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0);
  if (level < 0) {
    ALOGE("Failed to get memory tag level: %s", strerror(errno));
    return 0;
  } else if (!(level & PR_TAGGED_ADDR_ENABLE)) {
    return 0;
  }
  // TBI is only possible on non-MTE hardware.
  if (!mte_supported()) {
    return MEMORY_TAG_LEVEL_TBI;
  }

  switch (level & PR_MTE_TCF_MASK) {
    case PR_MTE_TCF_NONE:
      return 0;
    case PR_MTE_TCF_SYNC:
      return MEMORY_TAG_LEVEL_SYNC;
    case PR_MTE_TCF_ASYNC:
    case PR_MTE_TCF_ASYNC | PR_MTE_TCF_SYNC:
      return MEMORY_TAG_LEVEL_ASYNC;
    default:
      ALOGE("Unknown memory tagging level: %i", level);
      return 0;
  }
#else // defined(__aarch64__)
  return 0;
#endif // defined(__aarch64__)
}

static void com_android_internal_os_Zygote_nativeMarkOpenedFilesBeforePreload(JNIEnv* env, jclass) {
    // Ignore invocations when too early or too late.
    if (gPreloadFds) {
        return;
    }

    // App Zygote Preload starts soon. Save FDs remaining open.  After the
    // preload finishes newly open files will be determined.
    auto fail_fn = std::bind(zygote::ZygoteFailure, env, "zygote", nullptr, _1);
    gPreloadFds = GetOpenFds(fail_fn).release();
}

static void com_android_internal_os_Zygote_nativeAllowFilesOpenedByPreload(JNIEnv* env, jclass) {
    // Ignore invocations when too early or too late.
    if (!gPreloadFds || gPreloadFdsExtracted) {
        return;
    }

    // Find the newly open FDs, if any.
    auto fail_fn = std::bind(zygote::ZygoteFailure, env, "zygote", nullptr, _1);
    std::unique_ptr<std::set<int>> current_fds = GetOpenFds(fail_fn);
    auto difference = std::make_unique<std::set<int>>();
    std::set_difference(current_fds->begin(), current_fds->end(), gPreloadFds->begin(),
                        gPreloadFds->end(), std::inserter(*difference, difference->end()));
    delete gPreloadFds;
    gPreloadFds = difference.release();
    gPreloadFdsExtracted = true;
}

static const JNINativeMethod gMethods[] = {
        {"nativeForkAndSpecialize",
         "(II[II[[IILjava/lang/String;Ljava/lang/String;[I[IZLjava/lang/String;Ljava/lang/"
         "String;Z[Ljava/lang/String;[Ljava/lang/String;ZZ)I",
         (void*)com_android_internal_os_Zygote_nativeForkAndSpecialize},
        {"nativeForkSystemServer", "(II[II[[IJJ)I",
         (void*)com_android_internal_os_Zygote_nativeForkSystemServer},
        {"nativeAllowFileAcrossFork", "(Ljava/lang/String;)V",
         (void*)com_android_internal_os_Zygote_nativeAllowFileAcrossFork},
        {"nativePreApplicationInit", "()V",
         (void*)com_android_internal_os_Zygote_nativePreApplicationInit},
        {"nativeInstallSeccompUidGidFilter", "(II)V",
         (void*)com_android_internal_os_Zygote_nativeInstallSeccompUidGidFilter},
        {"nativeForkApp", "(II[IZZ)I", (void*)com_android_internal_os_Zygote_nativeForkApp},
        // @CriticalNative
        {"nativeAddUsapTableEntry", "(II)V",
         (void*)com_android_internal_os_Zygote_nativeAddUsapTableEntry},
        {"nativeSpecializeAppProcess",
         "(II[II[[IILjava/lang/String;Ljava/lang/String;ZLjava/lang/String;Ljava/lang/"
         "String;Z[Ljava/lang/String;[Ljava/lang/String;ZZ)V",
         (void*)com_android_internal_os_Zygote_nativeSpecializeAppProcess},
        {"nativeInitNativeState", "(Z)V",
         (void*)com_android_internal_os_Zygote_nativeInitNativeState},
        {"nativeGetUsapPipeFDs", "()[I",
         (void*)com_android_internal_os_Zygote_nativeGetUsapPipeFDs},
        // @CriticalNative
        {"nativeAddUsapTableEntry", "(II)V",
         (void*)com_android_internal_os_Zygote_nativeAddUsapTableEntry},
        // @CriticalNative
        {"nativeRemoveUsapTableEntry", "(I)Z",
         (void*)com_android_internal_os_Zygote_nativeRemoveUsapTableEntry},
        {"nativeGetUsapPoolEventFD", "()I",
         (void*)com_android_internal_os_Zygote_nativeGetUsapPoolEventFD},
        {"nativeGetUsapPoolCount", "()I",
         (void*)com_android_internal_os_Zygote_nativeGetUsapPoolCount},
        {"nativeEmptyUsapPool", "()V", (void*)com_android_internal_os_Zygote_nativeEmptyUsapPool},
        {"nativeBlockSigTerm", "()V", (void*)com_android_internal_os_Zygote_nativeBlockSigTerm},
        {"nativeUnblockSigTerm", "()V", (void*)com_android_internal_os_Zygote_nativeUnblockSigTerm},
        {"nativeBoostUsapPriority", "()V",
         (void*)com_android_internal_os_Zygote_nativeBoostUsapPriority},
        {"nativeParseSigChld", "([BI[I)I",
         (void*)com_android_internal_os_Zygote_nativeParseSigChld},
        {"nativeSupportsMemoryTagging", "()Z",
         (void*)com_android_internal_os_Zygote_nativeSupportsMemoryTagging},
        {"nativeSupportsTaggedPointers", "()Z",
         (void*)com_android_internal_os_Zygote_nativeSupportsTaggedPointers},
        {"nativeCurrentTaggingLevel", "()I",
         (void*)com_android_internal_os_Zygote_nativeCurrentTaggingLevel},
        {"nativeMarkOpenedFilesBeforePreload", "()V",
         (void*)com_android_internal_os_Zygote_nativeMarkOpenedFilesBeforePreload},
        {"nativeAllowFilesOpenedByPreload", "()V",
         (void*)com_android_internal_os_Zygote_nativeAllowFilesOpenedByPreload},
};

int register_com_android_internal_os_Zygote(JNIEnv* env) {
  gZygoteClass = MakeGlobalRefOrDie(env, FindClassOrDie(env, kZygoteClassName));
  gCallPostForkSystemServerHooks = GetStaticMethodIDOrDie(env, gZygoteClass,
                                                          "callPostForkSystemServerHooks",
                                                          "(I)V");
  gCallPostForkChildHooks = GetStaticMethodIDOrDie(env, gZygoteClass, "callPostForkChildHooks",
                                                   "(IZZLjava/lang/String;)V");

  gZygoteInitClass = MakeGlobalRefOrDie(env, FindClassOrDie(env, kZygoteInitClassName));
  gGetOrCreateSystemServerClassLoader =
          GetStaticMethodIDOrDie(env, gZygoteInitClass, "getOrCreateSystemServerClassLoader",
                                 "()Ljava/lang/ClassLoader;");
  gPrefetchStandaloneSystemServerJars =
          GetStaticMethodIDOrDie(env, gZygoteInitClass, "prefetchStandaloneSystemServerJars",
                                 "()V");

  RegisterMethodsOrDie(env, "com/android/internal/os/Zygote", gMethods, NELEM(gMethods));

  return JNI_OK;
}
}  // namespace android