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Merge changes from topic "apex_earlymount_no_bionic_bindmount"
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* changes:
  /bionic path is gone
  Revert "Handle adb sync with Bionic under /bionic"
  Don't bind-mount bionic files
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Treehugger Robot authored and Gerrit Code Review committed Mar 15, 2019
2 parents da1251d + 192fdeb commit 4cd0914
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Showing 7 changed files with 7 additions and 240 deletions.
86 changes: 0 additions & 86 deletions adb/daemon/file_sync_service.cpp
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Expand Up @@ -25,7 +25,6 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
Expand Down Expand Up @@ -211,22 +210,6 @@ static bool do_list(int s, const char* path) {
return WriteFdExactly(s, &msg.dent, sizeof(msg.dent));
}

static bool is_mountpoint(const std::string& path, pid_t tid) {
const std::string mountinfo_path = "/proc/" + std::to_string(tid) + "/mountinfo";
std::string mountinfo;
if (!android::base::ReadFileToString(mountinfo_path, &mountinfo)) {
PLOG(ERROR) << "Failed to open " << mountinfo_path;
return false;
}
std::vector<std::string> lines = android::base::Split(mountinfo, "\n");
return std::find_if(lines.begin(), lines.end(), [&path](const auto& line) {
auto tokens = android::base::Split(line, " ");
// line format is ...
// mountid parentmountid major:minor sourcepath targetpath option ...
return tokens.size() >= 4 && tokens[4] == path;
}) != lines.end();
}

// Make sure that SendFail from adb_io.cpp isn't accidentally used in this file.
#pragma GCC poison SendFail

Expand Down Expand Up @@ -432,18 +415,6 @@ static bool do_send(int s, const std::string& spec, std::vector<char>& buffer) {
struct stat st;
bool do_unlink = (lstat(path.c_str(), &st) == -1) || S_ISREG(st.st_mode) ||
(S_ISLNK(st.st_mode) && !S_ISLNK(mode));

// If the path is a file that is a mount point, don't unlink it, but instead
// truncate to zero. If unlinked, existing mounts on the path is all
// unmounted
if (S_ISREG(st.st_mode) && is_mountpoint(path, getpid())) {
do_unlink = false;
if (truncate(path.c_str(), 0) == -1) {
SendSyncFail(s, "truncate to zero failed");
return false;
}
}

if (do_unlink) {
adb_unlink(path.c_str());
}
Expand Down Expand Up @@ -591,64 +562,7 @@ static bool handle_sync_command(int fd, std::vector<char>& buffer) {
return true;
}

#if defined(__ANDROID__)
class FileSyncPreparer {
public:
FileSyncPreparer() : saved_ns_fd_(-1), rooted_(getuid() == 0) {
const std::string namespace_path = "/proc/" + std::to_string(gettid()) + "/ns/mnt";
const int ns_fd = adb_open(namespace_path.c_str(), O_RDONLY | O_CLOEXEC);
if (ns_fd == -1) {
if (rooted_) PLOG(ERROR) << "Failed to save mount namespace";
return;
}
saved_ns_fd_.reset(ns_fd);

// Note: this is for the current thread only
if (unshare(CLONE_NEWNS) != 0) {
if (rooted_) PLOG(ERROR) << "Failed to clone mount namespace";
return;
}

// Set the propagation type of / to private so that unmount below is
// not propagated to other mount namespaces.
if (mount(nullptr, "/", nullptr, MS_PRIVATE | MS_REC, nullptr) == -1) {
if (rooted_) PLOG(ERROR) << "Could not change propagation type of / to MS_PRIVATE";
return;
}

// unmount /bionic which is bind-mount to itself by init. Under /bionic,
// there are other bind mounts for the bionic files. By unmounting this,
// we unmount them all thus revealing the raw file system that is the
// same as the local file system seen by the adb client.
if (umount2("/bionic", MNT_DETACH) == -1 && errno != ENOENT) {
if (rooted_) PLOG(ERROR) << "Could not unmount /bionic to reveal raw filesystem";
return;
}
}

~FileSyncPreparer() {
if (saved_ns_fd_.get() != -1) {
// In fact, this is not strictly required because this thread for file
// sync service will be destroyed after the current transfer is all
// done. However, let's restore the ns in case the same thread is
// reused by multiple transfers in the future refactoring.
if (setns(saved_ns_fd_, CLONE_NEWNS) == -1) {
PLOG(ERROR) << "Failed to restore saved mount namespace";
}
}
}

private:
unique_fd saved_ns_fd_;
bool rooted_;
};
#endif

void file_sync_service(unique_fd fd) {
#if defined(__ANDROID__)
FileSyncPreparer preparer;
#endif

std::vector<char> buffer(SYNC_DATA_MAX);

while (handle_sync_command(fd.get(), buffer)) {
Expand Down
25 changes: 0 additions & 25 deletions fs_mgr/fs_mgr_remount.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -80,29 +80,6 @@ const android::fs_mgr::FstabEntry* is_wrapped(const android::fs_mgr::Fstab& over
return &(*it);
}

void try_unmount_bionic(android::fs_mgr::Fstab* mounts) {
static constexpr const char* kBionic = "/bionic";

auto entry = GetEntryForMountPoint(mounts, kBionic);
if (!entry) return;

struct statfs buf;
if (::statfs(kBionic, &buf) == -1) {
PLOG(ERROR) << "statfs of " << kBionic;
return;
}
if (buf.f_flags & MS_RDONLY) {
// /bionic is on a read-only partition; can happen for
// non-system-as-root-devices. Don' try to unmount.
return;
}
fs_mgr_set_blk_ro(entry->blk_device, false);
if (::mount(entry->blk_device.c_str(), entry->mount_point.c_str(), entry->fs_type.c_str(),
MS_REMOUNT, nullptr) == -1) {
PLOG(ERROR) << "remount of " << kBionic;
}
}

void MyLogger(android::base::LogId id, android::base::LogSeverity severity, const char* tag,
const char* file, unsigned int line, const char* message) {
static const char log_characters[] = "VD\0WEFF";
Expand Down Expand Up @@ -395,7 +372,5 @@ int main(int argc, char* argv[]) {

if (reboot_later) reboot(false);

try_unmount_bionic(&mounts);

return retval;
}
9 changes: 0 additions & 9 deletions init/builtins.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1118,14 +1118,6 @@ static Result<Success> do_parse_apex_configs(const BuiltinArguments& args) {
}
}

static Result<Success> do_setup_runtime_bionic(const BuiltinArguments& args) {
if (SetupRuntimeBionic()) {
return Success();
} else {
return Error() << "Failed to setup runtime bionic";
}
}

static Result<Success> do_enter_default_mount_ns(const BuiltinArguments& args) {
if (SwitchToDefaultMountNamespace()) {
return Success();
Expand Down Expand Up @@ -1181,7 +1173,6 @@ const BuiltinFunctionMap::Map& BuiltinFunctionMap::map() const {
{"rmdir", {1, 1, {true, do_rmdir}}},
{"setprop", {2, 2, {true, do_setprop}}},
{"setrlimit", {3, 3, {false, do_setrlimit}}},
{"setup_runtime_bionic", {0, 0, {false, do_setup_runtime_bionic}}},
{"start", {1, 1, {false, do_start}}},
{"stop", {1, 1, {false, do_stop}}},
{"swapon_all", {1, 1, {false, do_swapon_all}}},
Expand Down
120 changes: 5 additions & 115 deletions init/mount_namespace.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -33,37 +33,6 @@ namespace android {
namespace init {
namespace {

static constexpr const char* kLinkerMountPoint = "/bionic/bin/linker";
static constexpr const char* kBootstrapLinkerPath = "/system/bin/bootstrap/linker";
static constexpr const char* kRuntimeLinkerPath = "/apex/com.android.runtime/bin/linker";

static constexpr const char* kBionicLibsMountPointDir = "/bionic/lib/";
static constexpr const char* kBootstrapBionicLibsDir = "/system/lib/bootstrap/";
static constexpr const char* kRuntimeBionicLibsDir = "/apex/com.android.runtime/lib/bionic/";

static constexpr const char* kLinkerMountPoint64 = "/bionic/bin/linker64";
static constexpr const char* kBootstrapLinkerPath64 = "/system/bin/bootstrap/linker64";
static constexpr const char* kRuntimeLinkerPath64 = "/apex/com.android.runtime/bin/linker64";

static constexpr const char* kBionicLibsMountPointDir64 = "/bionic/lib64/";
static constexpr const char* kBootstrapBionicLibsDir64 = "/system/lib64/bootstrap/";
static constexpr const char* kRuntimeBionicLibsDir64 = "/apex/com.android.runtime/lib64/bionic/";

static const std::vector<std::string> kBionicLibFileNames = {"libc.so", "libm.so", "libdl.so"};

static bool BindMount(const std::string& source, const std::string& mount_point,
bool recursive = false) {
unsigned long mountflags = MS_BIND;
if (recursive) {
mountflags |= MS_REC;
}
if (mount(source.c_str(), mount_point.c_str(), nullptr, mountflags, nullptr) == -1) {
PLOG(ERROR) << "Could not bind-mount " << source << " to " << mount_point;
return false;
}
return true;
}

static bool MakeShared(const std::string& mount_point, bool recursive = false) {
unsigned long mountflags = MS_SHARED;
if (recursive) {
Expand Down Expand Up @@ -105,34 +74,6 @@ static std::string GetMountNamespaceId() {
return ret;
}

static bool BindMountBionic(const std::string& linker_source, const std::string& lib_dir_source,
const std::string& linker_mount_point,
const std::string& lib_mount_dir) {
if (access(linker_source.c_str(), F_OK) != 0) {
PLOG(INFO) << linker_source << " does not exist. skipping mounting bionic there.";
// This can happen for 64-bit bionic in 32-bit only device.
// It is okay to skip mounting the 64-bit bionic.
return true;
}
if (!BindMount(linker_source, linker_mount_point)) {
return false;
}
if (!MakePrivate(linker_mount_point)) {
return false;
}
for (const auto& libname : kBionicLibFileNames) {
std::string mount_point = lib_mount_dir + libname;
std::string source = lib_dir_source + libname;
if (!BindMount(source, mount_point)) {
return false;
}
if (!MakePrivate(mount_point)) {
return false;
}
}
return true;
}

static bool IsApexUpdatable() {
static bool updatable = android::sysprop::ApexProperties::updatable().value_or(false);
return updatable;
Expand All @@ -154,39 +95,19 @@ bool SetupMountNamespaces() {
// point to private.
if (!MakeShared("/", true /*recursive*/)) return false;

// Since different files (bootstrap or runtime APEX) should be mounted to
// the same mount point paths (e.g. /bionic/bin/linker, /bionic/lib/libc.so,
// etc.) across the two mount namespaces, we create a private mount point at
// /bionic so that a mount event for the bootstrap bionic in the mount
// namespace for pre-apexd processes is not propagated to the other mount
// namespace for post-apexd process, and vice versa.
//
// Other mount points other than /bionic, however, are all still shared.
if (!BindMount("/bionic", "/bionic", true /*recursive*/)) return false;
if (!MakePrivate("/bionic")) return false;

// Bind-mount bootstrap bionic.
if (!BindMountBionic(kBootstrapLinkerPath, kBootstrapBionicLibsDir, kLinkerMountPoint,
kBionicLibsMountPointDir))
return false;
if (!BindMountBionic(kBootstrapLinkerPath64, kBootstrapBionicLibsDir64, kLinkerMountPoint64,
kBionicLibsMountPointDir64))
return false;

// /apex is also a private mountpoint to give different sets of APEXes for
// /apex is a private mountpoint to give different sets of APEXes for
// the bootstrap and default mount namespaces. The processes running with
// the bootstrap namespace get APEXes from the read-only partition.
if (!(MakePrivate("/apex"))) return false;

bootstrap_ns_fd.reset(OpenMountNamespace());
bootstrap_ns_id = GetMountNamespaceId();

// When bionic is updatable via the runtime APEX, we create separate mount
// When APEXes are updatable (e.g. not-flattened), we create separate mount
// namespaces for processes that are started before and after the APEX is
// activated by apexd. In the namespace for pre-apexd processes, the bionic
// from the /system partition (that we call bootstrap bionic) is
// bind-mounted. In the namespace for post-apexd processes, the bionic from
// the runtime APEX is bind-mounted.
// activated by apexd. In the namespace for pre-apexd processes, small
// number of essential APEXes (e.g. com.android.runtime) are activated.
// In the namespace for post-apexd processes, all APEXes are activated.
bool success = true;
if (IsApexUpdatable() && !IsRecoveryMode()) {
// Creating a new namespace by cloning, saving, and switching back to
Expand All @@ -198,15 +119,6 @@ bool SetupMountNamespaces() {
default_ns_fd.reset(OpenMountNamespace());
default_ns_id = GetMountNamespaceId();

// By this unmount, the bootstrap bionic are not mounted in the default
// mount namespace.
if (umount2("/bionic", MNT_DETACH) == -1) {
PLOG(ERROR) << "Cannot unmount /bionic";
// Don't return here. We have to switch back to the bootstrap
// namespace.
success = false;
}

if (setns(bootstrap_ns_fd.get(), CLONE_NEWNS) == -1) {
PLOG(ERROR) << "Cannot switch back to bootstrap mount namespace";
return false;
Expand Down Expand Up @@ -237,28 +149,6 @@ bool SwitchToDefaultMountNamespace() {
return true;
}

// TODO(jiyong): remove this when /system/lib/libc.so becomes
// a symlink to /apex/com.android.runtime/lib/bionic/libc.so
bool SetupRuntimeBionic() {
if (IsRecoveryMode()) {
// We don't have multiple namespaces in recovery mode
return true;
}
// Bind-mount bionic from the runtime APEX since it is now available. Note
// that in case of IsApexUpdatable() == false, these mounts are over the
// existing existing bind mounts for the bootstrap bionic, which effectively
// becomes hidden.
if (!BindMountBionic(kRuntimeLinkerPath, kRuntimeBionicLibsDir, kLinkerMountPoint,
kBionicLibsMountPointDir))
return false;
if (!BindMountBionic(kRuntimeLinkerPath64, kRuntimeBionicLibsDir64, kLinkerMountPoint64,
kBionicLibsMountPointDir64))
return false;

LOG(INFO) << "Runtime bionic is set up";
return true;
}

bool SwitchToBootstrapMountNamespaceIfNeeded() {
if (IsRecoveryMode()) {
// we don't have multiple namespaces in recovery mode
Expand Down
1 change: 0 additions & 1 deletion init/mount_namespace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,6 @@ namespace android {
namespace init {

bool SetupMountNamespaces();
bool SetupRuntimeBionic();
bool SwitchToDefaultMountNamespace();
bool SwitchToBootstrapMountNamespaceIfNeeded();

Expand Down
4 changes: 2 additions & 2 deletions rootdir/etc/ld.config.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -83,7 +83,7 @@ namespace.default.permitted.paths += /%PRODUCT_SERVICES%/app
namespace.default.permitted.paths += /%PRODUCT_SERVICES%/priv-app
namespace.default.permitted.paths += /data
namespace.default.permitted.paths += /mnt/expand
namespace.default.permitted.paths += /bionic/${LIB}
namespace.default.permitted.paths += /apex/com.android.runtime/${LIB}/bionic
namespace.default.permitted.paths += /system/${LIB}/bootstrap

namespace.default.asan.search.paths = /data/asan/system/${LIB}
Expand Down Expand Up @@ -119,7 +119,7 @@ namespace.default.asan.permitted.paths += /%PRODUCT_SERVICES%/framework
namespace.default.asan.permitted.paths += /%PRODUCT_SERVICES%/app
namespace.default.asan.permitted.paths += /%PRODUCT_SERVICES%/priv-app
namespace.default.asan.permitted.paths += /mnt/expand
namespace.default.asan.permitted.paths += /bionic/${LIB}
namespace.default.asan.permitted.paths += /apex/com.android.runtime/${LIB}/bionic
namespace.default.asan.permitted.paths += /system/${LIB}/bootstrap

# Keep in sync with ld.config.txt in the com.android.runtime APEX.
Expand Down
2 changes: 0 additions & 2 deletions rootdir/init.rc
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Original file line number Diff line number Diff line change
Expand Up @@ -578,8 +578,6 @@ on post-fs-data

# Wait for apexd to finish activating APEXes before starting more processes.
wait_for_prop apexd.status ready
# TODO(jiyong): remove setup_runtime_bionic
setup_runtime_bionic
parse_apex_configs

init_user0
Expand Down

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