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Kernel+SystemServer: Simplify the DevTmpFS design

We are no longer have a separate Inode object class for the pts
directory. With a small exception to this, all chmod and chown code
is now at one place.
It's now possible to create any name of a sub-directory in the
filesystem.
This commit is contained in:
Liav A 2021-08-20 08:49:07 +03:00 committed by Andreas Kling
parent a7cb2ca1bf
commit 74c4c864bd
3 changed files with 171 additions and 175 deletions

View file

@ -47,6 +47,13 @@ DevTmpFSInode::DevTmpFSInode(DevTmpFS& fs)
{
}
DevTmpFSInode::DevTmpFSInode(DevTmpFS& fs, unsigned major_number, unsigned minor_number)
: Inode(fs, fs.allocate_inode_index())
, m_major_number(major_number)
, m_minor_number(minor_number)
{
}
KResultOr<size_t> DevTmpFSInode::read_bytes(off_t, size_t, UserOrKernelBuffer&, OpenFileDescription*) const
{
VERIFY_NOT_REACHED();
@ -73,27 +80,84 @@ KResultOr<size_t> DevTmpFSInode::write_bytes(off_t, size_t, const UserOrKernelBu
KResultOr<NonnullRefPtr<Inode>> DevTmpFSInode::create_child(StringView, mode_t, dev_t, UserID, GroupID)
{
return EROFS;
VERIFY_NOT_REACHED();
}
KResult DevTmpFSInode::add_child(Inode&, const StringView&, mode_t)
{
return EROFS;
VERIFY_NOT_REACHED();
}
InodeMetadata DevTmpFSInode::metadata() const
{
MutexLocker locker(m_inode_lock);
VERIFY((m_mode & 0777) == m_mode);
InodeMetadata metadata;
metadata.uid = m_uid;
metadata.gid = m_gid;
metadata.size = 0;
metadata.mtime = mepoch;
switch (node_type()) {
case Type::RootDirectory:
metadata.inode = { fsid(), 1 };
metadata.mode = 0040555;
metadata.uid = 0;
metadata.gid = 0;
metadata.size = 0;
metadata.mtime = mepoch;
break;
case Type::Directory:
metadata.inode = { fsid(), index() };
metadata.mode = S_IFDIR | m_mode;
break;
case Type::BlockDevice:
metadata.inode = { fsid(), index() };
metadata.mode = S_IFBLK | m_mode;
metadata.major_device = m_major_number;
metadata.minor_device = m_minor_number;
break;
case Type::CharacterDevice:
metadata.inode = { fsid(), index() };
metadata.mode = S_IFCHR | m_mode;
metadata.major_device = m_major_number;
metadata.minor_device = m_minor_number;
break;
case Type::Link:
metadata.inode = { fsid(), index() };
// FIXME: For now, it might not be possible to change the m_mode due to
// it pointing to another device node which its absolute_path() is not
// recognizable by the VirtualFileSystem.
// When we resolve the issues with the clunky absolute_path() interface,
// this should work out of the box...
metadata.mode = S_IFLNK | m_mode;
break;
default:
VERIFY_NOT_REACHED();
}
return metadata;
}
KResult DevTmpFSInode::remove_child(const StringView&)
{
return EROFS;
VERIFY_NOT_REACHED();
}
KResult DevTmpFSInode::chmod(mode_t)
KResult DevTmpFSInode::chmod(mode_t mode)
{
return EPERM;
MutexLocker locker(m_inode_lock);
mode &= 0777;
if (m_mode == mode)
return KSuccess;
m_mode = mode;
return KSuccess;
}
KResult DevTmpFSInode::chown(UserID, GroupID)
KResult DevTmpFSInode::chown(UserID uid, GroupID gid)
{
return EPERM;
MutexLocker locker(m_inode_lock);
m_uid = uid;
m_gid = gid;
return KSuccess;
}
KResult DevTmpFSInode::truncate(u64)
@ -125,18 +189,6 @@ KResultOr<size_t> DevTmpFSLinkInode::read_bytes(off_t offset, size_t, UserOrKern
return m_link->length();
}
InodeMetadata DevTmpFSLinkInode::metadata() const
{
InodeMetadata metadata;
metadata.inode = { fsid(), index() };
metadata.mode = S_IFLNK | 0555;
metadata.uid = 0;
metadata.gid = 0;
metadata.size = 0;
metadata.mtime = mepoch;
return metadata;
}
KResultOr<size_t> DevTmpFSLinkInode::write_bytes(off_t offset, size_t count, UserOrKernelBuffer const& buffer, OpenFileDescription*)
{
auto new_string = TRY(buffer.try_copy_into_kstring(count));
@ -152,30 +204,18 @@ DevTmpFSDirectoryInode::DevTmpFSDirectoryInode(DevTmpFS& fs)
: DevTmpFSInode(fs)
{
}
DevTmpFSDirectoryInode::DevTmpFSDirectoryInode(DevTmpFS& fs, NonnullOwnPtr<KString> name)
: DevTmpFSInode(fs)
, m_name(move(name))
{
}
DevTmpFSDirectoryInode::~DevTmpFSDirectoryInode()
{
}
InodeMetadata DevTmpFSDirectoryInode::metadata() const
KResult DevTmpFSDirectoryInode::traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)> callback) const
{
InodeMetadata metadata;
metadata.inode = { fsid(), 1 };
metadata.mode = 0040555;
metadata.uid = 0;
metadata.gid = 0;
metadata.size = 0;
metadata.mtime = mepoch;
return metadata;
}
DevTmpFSRootDirectoryInode::DevTmpFSRootDirectoryInode(DevTmpFS& fs)
: DevTmpFSDirectoryInode(fs)
{
}
KResult DevTmpFSRootDirectoryInode::traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)> callback) const
{
MutexLocker locker(fs().m_lock);
MutexLocker locker(m_inode_lock);
callback({ ".", identifier(), 0 });
callback({ "..", identifier(), 0 });
for (auto& node : m_nodes) {
@ -185,19 +225,20 @@ KResult DevTmpFSRootDirectoryInode::traverse_as_directory(Function<bool(FileSyst
return KSuccess;
}
KResultOr<NonnullRefPtr<Inode>> DevTmpFSRootDirectoryInode::lookup(StringView name)
KResultOr<NonnullRefPtr<Inode>> DevTmpFSDirectoryInode::lookup(StringView name)
{
MutexLocker locker(fs().m_lock);
MutexLocker locker(m_inode_lock);
for (auto& node : m_nodes) {
if (node.name() == name)
if (node.name() == name) {
return node;
}
return ENOENT;
}
return KResult(ENOENT);
}
KResult DevTmpFSRootDirectoryInode::remove_child(const StringView& name)
KResult DevTmpFSDirectoryInode::remove_child(const StringView& name)
{
MutexLocker locker(fs().m_lock);
MutexLocker locker(m_inode_lock);
for (auto& node : m_nodes) {
if (node.name() == name) {
m_nodes.remove(node);
@ -207,10 +248,9 @@ KResult DevTmpFSRootDirectoryInode::remove_child(const StringView& name)
return KResult(ENOENT);
}
KResultOr<NonnullRefPtr<Inode>> DevTmpFSRootDirectoryInode::create_child(StringView name, mode_t mode, dev_t device_mode, UserID, GroupID)
KResultOr<NonnullRefPtr<Inode>> DevTmpFSDirectoryInode::create_child(StringView name, mode_t mode, dev_t device_mode, UserID, GroupID)
{
MutexLocker locker(fs().m_lock);
MutexLocker locker(m_inode_lock);
for (auto& node : m_nodes) {
if (node.name() == name)
return KResult(EEXIST);
@ -219,9 +259,8 @@ KResultOr<NonnullRefPtr<Inode>> DevTmpFSRootDirectoryInode::create_child(StringV
InodeMetadata metadata;
metadata.mode = mode;
if (metadata.is_directory()) {
if (name != "pts")
return EROFS;
auto new_directory_inode = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) DevTmpFSPtsDirectoryInode(fs())));
auto name_kstring = TRY(KString::try_create(name));
auto new_directory_inode = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) DevTmpFSDirectoryInode(fs(), move(name_kstring))));
m_nodes.append(*new_directory_inode);
return new_directory_inode;
}
@ -237,32 +276,34 @@ KResultOr<NonnullRefPtr<Inode>> DevTmpFSRootDirectoryInode::create_child(StringV
if (metadata.is_symlink()) {
auto name_kstring = TRY(KString::try_create(name));
auto new_link_inode = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) DevTmpFSLinkInode(fs(), move(name_kstring))));
TRY(new_link_inode->chmod(mode));
m_nodes.append(*new_link_inode);
return new_link_inode;
}
return EROFS;
}
DevTmpFSRootDirectoryInode::DevTmpFSRootDirectoryInode(DevTmpFS& fs)
: DevTmpFSDirectoryInode(fs)
{
m_mode = 0555;
}
DevTmpFSRootDirectoryInode::~DevTmpFSRootDirectoryInode()
{
}
InodeMetadata DevTmpFSRootDirectoryInode::metadata() const
KResult DevTmpFSRootDirectoryInode::chmod(mode_t)
{
InodeMetadata metadata;
metadata.inode = { fsid(), 1 };
metadata.mode = 0040555;
metadata.uid = 0;
metadata.gid = 0;
metadata.size = 0;
metadata.mtime = mepoch;
return metadata;
return EPERM;
}
KResult DevTmpFSRootDirectoryInode::chown(UserID, GroupID)
{
return EPERM;
}
DevTmpFSDeviceInode::DevTmpFSDeviceInode(DevTmpFS& fs, unsigned major_number, unsigned minor_number, bool block_device, NonnullOwnPtr<KString> name)
: DevTmpFSInode(fs)
: DevTmpFSInode(fs, major_number, minor_number)
, m_name(move(name))
, m_major_number(major_number)
, m_minor_number(minor_number)
, m_block_device(block_device)
{
}
@ -271,24 +312,6 @@ DevTmpFSDeviceInode::~DevTmpFSDeviceInode()
{
}
KResult DevTmpFSDeviceInode::chown(UserID uid, GroupID gid)
{
MutexLocker locker(m_inode_lock);
m_uid = uid;
m_gid = gid;
return KSuccess;
}
KResult DevTmpFSDeviceInode::chmod(mode_t mode)
{
MutexLocker locker(m_inode_lock);
mode &= 0777;
if (m_required_mode == mode)
return KSuccess;
m_required_mode = mode;
return KSuccess;
}
StringView DevTmpFSDeviceInode::name() const
{
return m_name->view();
@ -309,20 +332,6 @@ KResultOr<size_t> DevTmpFSDeviceInode::read_bytes(off_t offset, size_t count, Us
return result.value();
}
InodeMetadata DevTmpFSDeviceInode::metadata() const
{
MutexLocker locker(m_inode_lock);
InodeMetadata metadata;
metadata.inode = { fsid(), index() };
metadata.mode = (m_block_device ? S_IFBLK : S_IFCHR) | m_required_mode;
metadata.uid = m_uid;
metadata.gid = m_gid;
metadata.size = 0;
metadata.mtime = mepoch;
metadata.major_device = m_major_number;
metadata.minor_device = m_minor_number;
return metadata;
}
KResultOr<size_t> DevTmpFSDeviceInode::write_bytes(off_t offset, size_t count, const UserOrKernelBuffer& buffer, OpenFileDescription* description)
{
MutexLocker locker(m_inode_lock);
@ -338,36 +347,4 @@ KResultOr<size_t> DevTmpFSDeviceInode::write_bytes(off_t offset, size_t count, c
return result.value();
}
DevTmpFSPtsDirectoryInode::DevTmpFSPtsDirectoryInode(DevTmpFS& fs)
: DevTmpFSDirectoryInode(fs)
{
}
KResult DevTmpFSPtsDirectoryInode::traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)> callback) const
{
MutexLocker locker(m_inode_lock);
callback({ ".", identifier(), 0 });
callback({ "..", identifier(), 0 });
return KSuccess;
}
KResultOr<NonnullRefPtr<Inode>> DevTmpFSPtsDirectoryInode::lookup(StringView)
{
return ENOENT;
}
DevTmpFSPtsDirectoryInode::~DevTmpFSPtsDirectoryInode()
{
}
InodeMetadata DevTmpFSPtsDirectoryInode::metadata() const
{
InodeMetadata metadata;
metadata.inode = { fsid(), index() };
metadata.mode = 0040555;
metadata.uid = 0;
metadata.gid = 0;
metadata.size = 0;
metadata.mtime = mepoch;
return metadata;
}
}

View file

@ -46,11 +46,13 @@ public:
DevTmpFS const& fs() const { return static_cast<DevTmpFS const&>(Inode::fs()); }
protected:
DevTmpFSInode(DevTmpFS&);
explicit DevTmpFSInode(DevTmpFS&);
DevTmpFSInode(DevTmpFS&, unsigned, unsigned);
virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
virtual KResultOr<NonnullRefPtr<Inode>> lookup(StringView name) override;
virtual void flush_metadata() override;
virtual InodeMetadata metadata() const override final;
virtual KResultOr<size_t> write_bytes(off_t, size_t, const UserOrKernelBuffer& buffer, OpenFileDescription*) override;
virtual KResultOr<NonnullRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) override;
virtual KResult add_child(Inode&, const StringView& name, mode_t) override;
@ -59,11 +61,27 @@ protected:
virtual KResult chown(UserID, GroupID) override;
virtual KResult truncate(u64) override;
mode_t m_mode { 0600 };
UserID m_uid { 0 };
GroupID m_gid { 0 };
const unsigned m_major_number { 0 };
const unsigned m_minor_number { 0 };
protected:
enum class Type {
BlockDevice,
CharacterDevice,
Directory,
RootDirectory,
Link
};
virtual Type node_type() const = 0;
private:
IntrusiveListNode<DevTmpFSInode, RefPtr<DevTmpFSInode>> m_list_node;
};
class DevTmpFSDeviceInode : public DevTmpFSInode {
class DevTmpFSDeviceInode final : public DevTmpFSInode {
friend class DevTmpFS;
friend class DevTmpFSRootDirectoryInode;
friend class DevTmpFSDirectoryInode;
@ -74,25 +92,20 @@ public:
private:
DevTmpFSDeviceInode(DevTmpFS&, unsigned, unsigned, bool, NonnullOwnPtr<KString> name);
// ^DevTmpFSInode
virtual Type node_type() const override { return m_block_device ? Type::BlockDevice : Type::CharacterDevice; }
// ^Inode
virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
virtual InodeMetadata metadata() const override;
virtual KResultOr<size_t> write_bytes(off_t, size_t, const UserOrKernelBuffer& buffer, OpenFileDescription*) override;
virtual KResult chown(UserID, GroupID) override;
virtual KResult chmod(mode_t) override;
NonnullOwnPtr<KString> m_name;
const unsigned m_major_number;
const unsigned m_minor_number;
const bool m_block_device;
mode_t m_required_mode;
UserID m_uid { 0 };
GroupID m_gid { 0 };
};
class DevTmpFSLinkInode : public DevTmpFSInode {
class DevTmpFSLinkInode final : public DevTmpFSInode {
friend class DevTmpFS;
friend class DevTmpFSRootDirectoryInode;
friend class DevTmpFSDirectoryInode;
public:
virtual StringView name() const override;
@ -100,9 +113,11 @@ public:
protected:
DevTmpFSLinkInode(DevTmpFS&, NonnullOwnPtr<KString>);
// ^DevTmpFSInode
virtual Type node_type() const override { return Type::Link; }
// ^Inode
virtual KResultOr<size_t> read_bytes(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
virtual InodeMetadata metadata() const override;
virtual KResultOr<size_t> write_bytes(off_t, size_t, const UserOrKernelBuffer& buffer, OpenFileDescription*) override;
NonnullOwnPtr<KString> m_name;
@ -115,28 +130,23 @@ class DevTmpFSDirectoryInode : public DevTmpFSInode {
public:
virtual ~DevTmpFSDirectoryInode() override;
virtual StringView name() const override { return m_name->view(); }
protected:
DevTmpFSDirectoryInode(DevTmpFS&);
// ^Inode
virtual InodeMetadata metadata() const override;
// ^DevTmpFSInode
virtual Type node_type() const override { return Type::Directory; }
IntrusiveList<DevTmpFSInode, NonnullRefPtr<DevTmpFSInode>, &DevTmpFSInode::m_list_node> m_nodes;
};
class DevTmpFSPtsDirectoryInode final : public DevTmpFSDirectoryInode {
friend class DevTmpFS;
friend class DevTmpFSRootDirectoryInode;
public:
virtual ~DevTmpFSPtsDirectoryInode() override;
virtual StringView name() const override { return "pts"; };
private:
explicit DevTmpFSPtsDirectoryInode(DevTmpFS&);
virtual KResultOr<NonnullRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) override;
virtual KResult remove_child(const StringView& name) override;
virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
virtual KResultOr<NonnullRefPtr<Inode>> lookup(StringView name) override;
virtual InodeMetadata metadata() const override;
DevTmpFSDirectoryInode(DevTmpFS&, NonnullOwnPtr<KString> name);
// ^Inode
OwnPtr<KString> m_name;
IntrusiveList<DevTmpFSInode, NonnullRefPtr<DevTmpFSInode>, &DevTmpFSInode::m_list_node> m_nodes;
private:
explicit DevTmpFSDirectoryInode(DevTmpFS&);
};
class DevTmpFSRootDirectoryInode final : public DevTmpFSDirectoryInode {
@ -147,12 +157,12 @@ public:
virtual StringView name() const override { return "."; }
private:
// ^DevTmpFSInode
virtual Type node_type() const override { return Type::Directory; }
explicit DevTmpFSRootDirectoryInode(DevTmpFS&);
virtual KResultOr<NonnullRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) override;
virtual KResult traverse_as_directory(Function<bool(FileSystem::DirectoryEntryView const&)>) const override;
virtual KResultOr<NonnullRefPtr<Inode>> lookup(StringView name) override;
virtual InodeMetadata metadata() const override;
virtual KResult remove_child(const StringView& name) override;
virtual KResult chmod(mode_t) override;
virtual KResult chown(UserID, GroupID) override;
};
}

View file

@ -83,6 +83,13 @@ static void chown_wrapper(const char* path, uid_t uid, gid_t gid)
VERIFY_NOT_REACHED();
}
}
static void chmod_wrapper(const char* path, mode_t mode)
{
int rc = chmod(path, mode);
if (rc < 0 && errno != ENOENT) {
VERIFY_NOT_REACHED();
}
}
static void chown_all_matching_device_nodes(group* group, unsigned major_number)
{
@ -341,6 +348,21 @@ static void prepare_synthetic_filesystems()
VERIFY_NOT_REACHED();
}
rc = symlink("/proc/self/fd/0", "/dev/stdin");
if (rc < 0) {
VERIFY_NOT_REACHED();
}
rc = symlink("/proc/self/fd/1", "/dev/stdout");
if (rc < 0) {
VERIFY_NOT_REACHED();
}
rc = symlink("/proc/self/fd/2", "/dev/stderr");
if (rc < 0) {
VERIFY_NOT_REACHED();
}
populate_devfs();
rc = mkdir("/dev/pts", 0755);
@ -357,6 +379,7 @@ static void prepare_synthetic_filesystems()
if (rc < 0) {
VERIFY_NOT_REACHED();
}
chmod_wrapper("/dev/urandom", 0666);
auto phys_group = getgrnam("phys");
VERIFY(phys_group);
@ -376,19 +399,6 @@ static void prepare_synthetic_filesystems()
VERIFY(audio_group);
chown_wrapper("/dev/audio", 0, audio_group->gr_gid);
rc = symlink("/proc/self/fd/0", "/dev/stdin");
if (rc < 0) {
VERIFY_NOT_REACHED();
}
rc = symlink("/proc/self/fd/1", "/dev/stdout");
if (rc < 0) {
VERIFY_NOT_REACHED();
}
rc = symlink("/proc/self/fd/2", "/dev/stderr");
if (rc < 0) {
VERIFY_NOT_REACHED();
}
// Note: We open the /dev/null device and set file descriptors 0, 1, 2 to it
// because otherwise these file descriptors won't have a custody, making
// the ProcFS file descriptor links (at /proc/PID/fd/{0,1,2}) to have an
@ -396,7 +406,6 @@ static void prepare_synthetic_filesystems()
// This affects also every other process that inherits the file descriptors
// from SystemServer, so it is important for other things (also for ProcFS
// tests that are running in CI mode).
int stdin_new_fd = open("/dev/null", O_NONBLOCK);
if (stdin_new_fd < 0) {
VERIFY_NOT_REACHED();