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kakoune/src/remote.cc

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#include "remote.hh"
#include "buffer_manager.hh"
#include "buffer_utils.hh"
#include "client_manager.hh"
#include "command_manager.hh"
#include "display_buffer.hh"
#include "event_manager.hh"
#include "file.hh"
#include "hash_map.hh"
#include "optional.hh"
#include "user_interface.hh"
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <pwd.h>
#include <fcntl.h>
#include <errno.h>
namespace Kakoune
{
enum class MessageType : uint8_t
{
Unknown,
Connect,
Command,
MenuShow,
MenuSelect,
MenuHide,
InfoShow,
InfoHide,
Draw,
DrawStatus,
SetCursor,
Refresh,
SetOptions,
Exit,
Key,
Paste,
};
class MsgWriter
{
public:
MsgWriter(RemoteBuffer& buffer, MessageType type)
: m_buffer{buffer}, m_start{(uint32_t)buffer.size()}
{
write_field(type);
write_field((uint32_t)0); // message size, to be patched on write
}
~MsgWriter()
{
uint32_t count = (uint32_t)m_buffer.size() - m_start;
memcpy(m_buffer.data() + m_start + sizeof(MessageType), &count, sizeof(uint32_t));
}
template<typename ...Args>
void write(Args&&... args)
{
(write_field(std::forward<Args>(args)), ...);
}
private:
void write_raw(const char* val, size_t size)
{
m_buffer.insert(m_buffer.end(), val, val + size);
}
template<typename T>
void write_field(const T& val)
{
static_assert(std::is_trivially_copyable<T>::value, "");
write_raw((const char*)&val, sizeof(val));
}
void write_field(StringView str)
{
write_field(str.length());
write_raw(str.data(), (int)str.length());
};
void write_field(const String& str)
{
write_field(StringView{str});
}
template<typename T>
void write_field(ConstArrayView<T> view)
{
write_field<uint32_t>(view.size());
for (auto& val : view)
write_field(val);
}
template<typename T, MemoryDomain domain>
void write_field(const Vector<T, domain>& vec)
{
write_field(ConstArrayView<T>(vec));
}
template<typename Key, typename Val, MemoryDomain domain>
void write_field(const HashMap<Key, Val, domain>& map)
{
write_field<uint32_t>(map.size());
for (auto& val : map)
{
write_field(val.key);
write_field(val.value);
}
}
template<typename T>
void write_field(const Optional<T>& val)
{
write_field((bool)val);
if (val)
write_field(*val);
}
void write_field(Color color)
{
write_field(color.color);
if (color.isRGB())
{
write_field(color.r);
write_field(color.g);
write_field(color.b);
}
}
void write_field(const DisplayAtom& atom)
{
write_field(atom.content());
write_field(atom.face);
}
void write_field(const DisplayLine& line)
{
write_field(line.atoms());
}
void write_field(const DisplayBuffer& display_buffer)
{
write_field(display_buffer.lines());
}
private:
RemoteBuffer& m_buffer;
uint32_t m_start;
};
class MsgReader
{
private:
template<typename T>
struct Reader {
static T read(MsgReader& reader)
{
static_assert(std::is_trivially_copyable<T>::value, "");
T res;
reader.read(reinterpret_cast<char*>(&res), sizeof(T));
return res;
}
};
template<typename T, MemoryDomain domain>
struct Reader<Vector<T,domain>> {
static Vector<T, domain> read(MsgReader& reader)
{
uint32_t size = Reader<uint32_t>::read(reader);
Vector<T,domain> res;
res.reserve(size);
while (size--)
res.push_back(std::move(Reader<T>::read(reader)));
return res;
}
};
template<typename T>
struct Reader<ArrayView<T>> : Reader<Vector<std::remove_cv_t<T>, MemoryDomain::Undefined>> {};
template<typename Key, typename Value, MemoryDomain domain>
struct Reader<HashMap<Key, Value, domain>> {
static HashMap<Key, Value, domain> read(MsgReader& reader)
{
uint32_t size = Reader<uint32_t>::read(reader);
HashMap<Key, Value, domain> res;
res.reserve(size);
while (size--)
{
auto key = Reader<Key>::read(reader);
auto val = Reader<Value>::read(reader);
res.insert({std::move(key), std::move(val)});
}
return res;
}
};
template<typename T>
struct Reader<Optional<T>> {
static Optional<T> read(MsgReader& reader)
{
if (not Reader<bool>::read(reader))
return {};
return Reader<T>::read(reader);
}
};
public:
void read_available(int sock)
{
if (m_write_pos < header_size)
{
m_stream.resize(header_size);
read_from_socket(sock, header_size - m_write_pos);
if (m_write_pos == header_size)
{
if (size() < header_size)
throw disconnected{"invalid message received"};
m_stream.resize(size());
}
}
else
read_from_socket(sock, size() - m_write_pos);
}
bool ready() const
{
return m_write_pos >= header_size and m_write_pos == size();
}
uint32_t size() const
{
kak_assert(m_write_pos >= header_size);
uint32_t res;
memcpy(&res, m_stream.data() + sizeof(MessageType), sizeof(uint32_t));
return res;
}
MessageType type() const
{
kak_assert(m_write_pos >= header_size);
return *reinterpret_cast<const MessageType*>(m_stream.data());
}
void read(char* buffer, size_t size)
{
if (m_read_pos + size > m_stream.size())
throw disconnected{"tried to read after message end"};
memcpy(buffer, m_stream.data() + m_read_pos, size);
m_read_pos += size;
}
template<typename T>
auto read()
{
return Reader<T>::read(*this);
}
Optional<int> ancillary_fd()
{
auto res = m_ancillary_fd;
m_ancillary_fd.reset();
return res;
}
~MsgReader()
{
m_ancillary_fd.map(close);
}
void reset()
{
m_stream.resize(0);
m_write_pos = 0;
m_read_pos = header_size;
m_ancillary_fd.map(close);
}
private:
void read_from_socket(int sock, size_t size)
{
kak_assert(m_write_pos + size <= m_stream.size());
iovec io{m_stream.data() + m_write_pos, size};
alignas(cmsghdr) char fdbuf[CMSG_SPACE(sizeof(int))];
msghdr msg{};
msg.msg_iov = &io;
msg.msg_iovlen = 1;
msg.msg_control = fdbuf;
msg.msg_controllen = sizeof(fdbuf);
int res = recvmsg(sock, &msg, 0);
if (res <= 0)
throw disconnected{format("socket read failed: {}", strerror(errno))};
m_write_pos += res;
if (cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
cmsg && cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS && cmsg->cmsg_len == CMSG_LEN(sizeof(int)))
{
m_ancillary_fd.map(close);
memcpy(&m_ancillary_fd.emplace(), CMSG_DATA(cmsg), sizeof(int));
fcntl(*m_ancillary_fd, F_SETFD, FD_CLOEXEC);
}
}
static constexpr uint32_t header_size = sizeof(MessageType) + sizeof(uint32_t);
Vector<char, MemoryDomain::Remote> m_stream;
Optional<int> m_ancillary_fd;
uint32_t m_write_pos = 0;
uint32_t m_read_pos = header_size;
};
template<>
struct MsgReader::Reader<String> {
static String read(MsgReader& reader)
{
ByteCount length = Reader<ByteCount>::read(reader);
String res;
if (length > 0)
{
res.force_size((int)length);
reader.read(&res[0_byte], (int)length);
}
return res;
}
};
template<>
struct MsgReader::Reader<Color> {
static Color read(MsgReader& reader)
{
Color res;
res.color = Reader<Color::NamedColor>::read(reader);
if (res.isRGB())
{
res.r = Reader<unsigned char>::read(reader);
res.g = Reader<unsigned char>::read(reader);
res.b = Reader<unsigned char>::read(reader);
}
return res;
}
};
template<>
struct MsgReader::Reader<DisplayAtom> {
static DisplayAtom read(MsgReader& reader)
{
String content = Reader<String>::read(reader);
return {std::move(content), Reader<Face>::read(reader)};
}
};
template<>
struct MsgReader::Reader<DisplayLine> {
static DisplayLine read(MsgReader& reader)
{
return {Reader<Vector<DisplayAtom>>::read(reader)};
}
};
template<>
struct MsgReader::Reader<DisplayBuffer> {
static DisplayBuffer read(MsgReader& reader)
{
DisplayBuffer db;
db.lines() = Reader<Vector<DisplayLine>>::read(reader);
return db;
}
};
class RemoteUI : public UserInterface
{
public:
RemoteUI(int socket, DisplayCoord dimensions);
~RemoteUI() override;
bool is_ok() const override { return m_socket_watcher.fd() != -1; }
void menu_show(ConstArrayView<DisplayLine> choices,
DisplayCoord anchor, Face fg, Face bg,
MenuStyle style) override;
void menu_select(int selected) override;
void menu_hide() override;
void info_show(const DisplayLine& title, const DisplayLineList& content,
DisplayCoord anchor, Face face,
InfoStyle style) override;
void info_hide() override;
void draw(const DisplayBuffer& display_buffer,
const Face& default_face,
const Face& padding_face) override;
void draw_status(const DisplayLine& status_line,
const DisplayLine& mode_line,
const Face& default_face) override;
void set_cursor(CursorMode mode, DisplayCoord coord) override;
void refresh(bool force) override;
DisplayCoord dimensions() override { return m_dimensions; }
void set_on_key(OnKeyCallback callback) override
{ m_on_key = std::move(callback); }
void set_on_paste(OnPasteCallback callback) override
{ m_on_paste = std::move(callback); }
void set_ui_options(const Options& options) override;
void exit(int status);
private:
template<typename ...Args>
void send_message(MessageType type, Args&&... args)
{
MsgWriter msg{m_send_buffer, type};
msg.write(std::forward<Args>(args)...);
m_socket_watcher.events() |= FdEvents::Write;
}
FDWatcher m_socket_watcher;
MsgReader m_reader;
DisplayCoord m_dimensions;
OnKeyCallback m_on_key;
OnPasteCallback m_on_paste;
RemoteBuffer m_send_buffer;
};
static bool send_data(int fd, RemoteBuffer& buffer, Optional<int> ancillary_fd = {})
{
while (not buffer.empty() and fd_writable(fd))
{
iovec io{buffer.data(), buffer.size()};
alignas(cmsghdr) char fdbuf[CMSG_SPACE(sizeof(int))];
msghdr msg{};
msg.msg_iov = &io;
msg.msg_iovlen = 1;
if (ancillary_fd)
{
msg.msg_control = fdbuf;
msg.msg_controllen = sizeof(fdbuf);
cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
memcpy(CMSG_DATA(cmsg), &*ancillary_fd, sizeof(int));
}
int res = sendmsg(fd, &msg, 0);
if (res <= 0)
throw disconnected{format("socket write failed: {}", strerror(errno))};
buffer.erase(buffer.begin(), buffer.begin() + res);
}
return buffer.empty();
}
RemoteUI::RemoteUI(int socket, DisplayCoord dimensions)
: m_socket_watcher(socket, FdEvents::Read | FdEvents::Write, EventMode::Urgent,
[this](FDWatcher& watcher, FdEvents events, EventMode) {
const int sock = watcher.fd();
try
{
if (events & FdEvents::Write and send_data(sock, m_send_buffer))
m_socket_watcher.events() &= ~FdEvents::Write;
while (events & FdEvents::Read and fd_readable(sock))
{
m_reader.read_available(sock);
if (not m_reader.ready())
continue;
if (m_reader.type() == MessageType::Key)
{
auto key = m_reader.read<Key>();
m_reader.reset();
if (key.modifiers == Key::Modifiers::Resize)
m_dimensions = key.coord();
m_on_key(key);
}
else if (m_reader.type() == MessageType::Paste)
{
auto content = m_reader.read<String>();
m_reader.reset();
m_on_paste(content);
}
else
{
m_socket_watcher.close_fd();
return;
}
}
}
catch (const disconnected& err)
{
write_to_debug_buffer(format("Error while transfering remote messages: {}", err.what()));
m_socket_watcher.close_fd();
}
}),
m_dimensions(dimensions)
{
write_to_debug_buffer(format("remote client connected: {}", m_socket_watcher.fd()));
}
RemoteUI::~RemoteUI()
{
// Try to send the remaining data if possible, as it might contain the desired exit status
try
{
if (m_socket_watcher.fd() != -1)
send_data(m_socket_watcher.fd(), m_send_buffer);
}
catch (disconnected&)
{
}
write_to_debug_buffer(format("remote client disconnected: {}", m_socket_watcher.fd()));
m_socket_watcher.close_fd();
}
void RemoteUI::menu_show(ConstArrayView<DisplayLine> choices,
DisplayCoord anchor, Face fg, Face bg,
MenuStyle style)
{
send_message(MessageType::MenuShow, choices, anchor, fg, bg, style);
}
void RemoteUI::menu_select(int selected)
{
send_message(MessageType::MenuSelect, selected);
}
void RemoteUI::menu_hide()
{
send_message(MessageType::MenuHide);
}
void RemoteUI::info_show(const DisplayLine& title, const DisplayLineList& content,
DisplayCoord anchor, Face face,
InfoStyle style)
{
send_message(MessageType::InfoShow, title, content, anchor, face, style);
}
void RemoteUI::info_hide()
{
send_message(MessageType::InfoHide);
}
void RemoteUI::draw(const DisplayBuffer& display_buffer,
const Face& default_face,
const Face& padding_face)
{
send_message(MessageType::Draw, display_buffer, default_face, padding_face);
}
void RemoteUI::draw_status(const DisplayLine& status_line,
const DisplayLine& mode_line,
const Face& default_face)
{
send_message(MessageType::DrawStatus, status_line, mode_line, default_face);
}
void RemoteUI::set_cursor(CursorMode mode, DisplayCoord coord)
{
send_message(MessageType::SetCursor, mode, coord);
}
void RemoteUI::refresh(bool force)
{
send_message(MessageType::Refresh, force);
}
void RemoteUI::set_ui_options(const Options& options)
{
send_message(MessageType::SetOptions, options);
}
void RemoteUI::exit(int status)
{
send_message(MessageType::Exit, status);
}
String get_user_name()
{
auto pw = getpwuid(geteuid());
if (pw)
return pw->pw_name;
return getenv("USER");
}
const String& session_directory()
{
static String session_dir = [] {
StringView xdg_runtime_dir = getenv("XDG_RUNTIME_DIR");
if (not xdg_runtime_dir.empty())
{
if (struct stat st; stat(xdg_runtime_dir.zstr(), &st) == 0 && st.st_uid == geteuid())
return format("{}/kakoune", xdg_runtime_dir);
else
write_to_debug_buffer("XDG_RUNTIME_DIR does not exist or not owned by current user, using tmpdir");
}
return format("{}/kakoune-{}", tmpdir(), get_user_name());
}();
return session_dir;
}
String session_path(StringView session)
{
if (not all_of(session, is_identifier))
throw runtime_error{format("invalid session name: '{}'", session)};
return format("{}/{}", session_directory(), session);
}
static sockaddr_un session_addr(StringView session)
{
sockaddr_un addr;
addr.sun_family = AF_UNIX;
String path = session_path(session);
if (path.length() + 1 > sizeof addr.sun_path)
throw runtime_error{format("socket path too long: '{}'", path)};
strcpy(addr.sun_path, path.c_str());
return addr;
}
static int connect_to(StringView session)
{
int sock = socket(AF_UNIX, SOCK_STREAM, 0);
fcntl(sock, F_SETFD, FD_CLOEXEC);
sockaddr_un addr = session_addr(session);
if (connect(sock, (sockaddr*)&addr, sizeof(addr.sun_path)) == -1)
throw disconnected(format("connect to {} failed", addr.sun_path));
return sock;
}
bool check_session(StringView session)
{
int sock = socket(AF_UNIX, SOCK_STREAM, 0);
auto close_sock = on_scope_end([sock]{ close(sock); });
sockaddr_un addr = session_addr(session);
return connect(sock, (sockaddr*)&addr, sizeof(addr.sun_path)) != -1;
}
RemoteClient::RemoteClient(StringView session, StringView name, std::unique_ptr<UserInterface>&& ui,
int pid, const EnvVarMap& env_vars, StringView init_command,
Optional<BufferCoord> init_coord, Optional<int> stdin_fd)
: m_ui(std::move(ui))
{
int sock = connect_to(session);
{
MsgWriter msg{m_send_buffer, MessageType::Connect};
msg.write(pid, name, init_command, init_coord, m_ui->dimensions(), env_vars);
}
send_data(sock, m_send_buffer, stdin_fd);
m_ui->set_on_key([this](Key key){
MsgWriter msg(m_send_buffer, MessageType::Key);
msg.write(key);
m_socket_watcher->events() |= FdEvents::Write;
});
m_ui->set_on_paste([this](StringView content){
MsgWriter msg(m_send_buffer, MessageType::Paste);
msg.write(content);
m_socket_watcher->events() |= FdEvents::Write;
});
m_socket_watcher.reset(new FDWatcher{sock, FdEvents::Read | FdEvents::Write, EventMode::Urgent,
[this, reader = MsgReader{}](FDWatcher& watcher, FdEvents events, EventMode) mutable {
const int sock = watcher.fd();
if (events & FdEvents::Write and send_data(sock, m_send_buffer))
watcher.events() &= ~FdEvents::Write;
auto exec = [&]<typename ...Args>(void (UserInterface::*method)(Args...)) {
struct Impl // Use a constructor to ensure left-to-right parameter evaluation
{
Impl(UserInterface& ui, void (UserInterface::*method)(Args...), Args... args)
{
(ui.*method)(std::forward<Args>(args)...);
}
};
Impl{*m_ui, method, reader.read<std::remove_cvref_t<Args>>()...};
};
while (events & FdEvents::Read and
not reader.ready() and fd_readable(sock))
{
reader.read_available(sock);
if (not reader.ready())
continue;
auto clear_reader = on_scope_end([&reader] { reader.reset(); });
switch (reader.type())
{
case MessageType::MenuShow:
exec(&UserInterface::menu_show);
break;
case MessageType::MenuSelect:
exec(&UserInterface::menu_select);
break;
case MessageType::MenuHide:
exec(&UserInterface::menu_hide);
break;
case MessageType::InfoShow:
exec(&UserInterface::info_show);
break;
case MessageType::InfoHide:
exec(&UserInterface::info_hide);
break;
case MessageType::Draw:
exec(&UserInterface::draw);
break;
case MessageType::DrawStatus:
exec(&UserInterface::draw_status);
break;
case MessageType::SetCursor:
exec(&UserInterface::set_cursor);
break;
case MessageType::Refresh:
exec(&UserInterface::refresh);
break;
case MessageType::SetOptions:
exec(&UserInterface::set_ui_options);
break;
case MessageType::Exit:
m_exit_status = reader.read<int>();
watcher.close_fd();
return;
default:
kak_assert(false);
}
}
}});
}
bool RemoteClient::is_ui_ok() const
{
return m_ui->is_ok();
}
void send_command(StringView session, StringView command)
{
int sock = connect_to(session);
auto close_sock = on_scope_end([sock]{ close(sock); });
RemoteBuffer buffer;
{
MsgWriter msg{buffer, MessageType::Command};
msg.write(command);
}
write(sock, {buffer.data(), buffer.data() + buffer.size()});
}
// A client accepter handle a connection until it closes or a nul byte is
// recieved. Everything recieved before is considered to be a command.
//
// * When a nul byte is recieved, the socket is handed to a new Client along
// with the command.
// * When the connection is closed, the command is run in an empty context.
class Server::Accepter
{
public:
Accepter(int socket)
: m_socket_watcher(socket, FdEvents::Read, EventMode::Urgent,
[this](FDWatcher&, FdEvents, EventMode mode) {
handle_available_input(mode);
})
{}
private:
void handle_available_input(EventMode mode)
{
const int sock = m_socket_watcher.fd();
try
{
while (not m_reader.ready() and fd_readable(sock))
m_reader.read_available(sock);
if (mode != EventMode::Normal or not m_reader.ready())
return;
switch (m_reader.type())
{
case MessageType::Connect:
{
auto pid = m_reader.read<int>();
auto name = m_reader.read<String>();
auto init_cmds = m_reader.read<String>();
auto init_coord = m_reader.read<Optional<BufferCoord>>();
auto dimensions = m_reader.read<DisplayCoord>();
auto env_vars = m_reader.read<HashMap<String, String, MemoryDomain::EnvVars>>();
if (auto stdin_fd = m_reader.ancillary_fd())
create_fifo_buffer(generate_buffer_name("*stdin-{}*"), *stdin_fd, Buffer::Flags::None);
auto* ui = new RemoteUI{sock, dimensions};
ClientManager::instance().create_client(
std::unique_ptr<UserInterface>(ui), pid, std::move(name),
std::move(env_vars), init_cmds, {}, init_coord,
[ui](int status) { ui->exit(status); });
Server::instance().remove_accepter(this);
break;
}
case MessageType::Command:
{
auto command = m_reader.read<String>();
if (not command.empty()) try
{
Context context{Context::EmptyContextFlag{}};
CommandManager::instance().execute(command, context);
}
catch (const runtime_error& e)
{
write_to_debug_buffer(format("error running command '{}': {}",
command, e.what()));
}
close(sock);
Server::instance().remove_accepter(this);
break;
}
default:
write_to_debug_buffer("invalid introduction message received");
close(sock);
Server::instance().remove_accepter(this);
}
}
catch (const disconnected& err)
{
write_to_debug_buffer(format("accepting connection failed: {}", err.what()));
close(sock);
Server::instance().remove_accepter(this);
}
}
FDWatcher m_socket_watcher;
MsgReader m_reader;
};
Server::Server(String session_name, bool is_daemon)
: m_session{std::move(session_name)}, m_is_daemon{is_daemon}
{
int listen_sock = socket(AF_UNIX, SOCK_STREAM, 0);
fcntl(listen_sock, F_SETFD, FD_CLOEXEC);
sockaddr_un addr = session_addr(m_session);
make_directory(session_directory(), 0711);
// Do not give any access to the socket to other users by default
auto old_mask = umask(0077);
auto restore_mask = on_scope_end([old_mask]() { umask(old_mask); });
if (bind(listen_sock, (sockaddr*) &addr, sizeof(sockaddr_un)) == -1)
throw runtime_error(format("unable to bind listen socket '{}': {}",
addr.sun_path, strerror(errno)));
if (listen(listen_sock, 4) == -1)
throw runtime_error(format("unable to listen on socket '{}': {}",
addr.sun_path, strerror(errno)));
auto accepter = [this](FDWatcher& watcher, FdEvents, EventMode) {
sockaddr_un client_addr;
socklen_t client_addr_len = sizeof(sockaddr_un);
int sock = accept(watcher.fd(), (sockaddr*) &client_addr,
&client_addr_len);
if (sock == -1)
throw runtime_error("accept failed");
fcntl(sock, F_SETFD, FD_CLOEXEC);
m_accepters.emplace_back(new Accepter{sock});
};
m_listener.reset(new FDWatcher{listen_sock, FdEvents::Read, EventMode::Urgent, accepter});
}
bool Server::rename_session(StringView name)
{
String old_socket_file = session_path(m_session);
String new_socket_file = session_path(name);
if (file_exists(new_socket_file))
return false;
if (rename(old_socket_file.c_str(), new_socket_file.c_str()) != 0)
return false;
m_session = name.str();
return true;
}
void Server::close_session(bool do_unlink)
{
if (do_unlink)
{
String socket_file = session_path(m_session);
unlink(socket_file.c_str());
}
m_listener->close_fd();
m_listener.reset();
}
Server::~Server()
{
if (m_listener)
close_session();
}
void Server::remove_accepter(Accepter* accepter)
{
auto it = find(m_accepters, accepter);
kak_assert(it != m_accepters.end());
m_accepters.erase(it);
}
}
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