hyprland/src/xwayland/Server.cpp
davc0n e5df8cdc62
xwayland: refactor class member vars (#10312)
* xwayland: refactor class member vars

* xwayland: fix pure wayland build
2025-05-07 15:21:44 +02:00

423 lines
12 KiB
C++

#include <cstdint>
#ifndef NO_XWAYLAND
#include <format>
#include <string>
#include <cerrno>
#include <fcntl.h>
#include <cstdio>
#include <cstring>
#include <csignal>
#include <cstddef>
#include <cstdlib>
#include <sys/un.h>
#include <unistd.h>
#include <exception>
#include <filesystem>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include "Server.hpp"
#include "XWayland.hpp"
#include "config/ConfigValue.hpp"
#include "debug/Log.hpp"
#include "../defines.hpp"
#include "../Compositor.hpp"
#include "../managers/CursorManager.hpp"
using namespace Hyprutils::OS;
// Constants
constexpr int SOCKET_DIR_PERMISSIONS = 0755;
constexpr int SOCKET_BACKLOG = 1;
constexpr int MAX_SOCKET_RETRIES = 32;
constexpr int LOCK_FILE_MODE = 0444;
static CFileDescriptor createSocket(struct sockaddr_un* addr, size_t pathSize) {
const bool isRegularSocket(addr->sun_path[0]);
const char dbgSocketPathPrefix = isRegularSocket ? addr->sun_path[0] : '@';
const char* const dbgSocketPathRem = addr->sun_path + 1;
socklen_t size = offsetof(struct sockaddr_un, sun_path) + pathSize + 1;
CFileDescriptor fd{socket(AF_UNIX, SOCK_STREAM, 0)};
if (!fd.isValid()) {
Debug::log(ERR, "Failed to create socket {}{}", dbgSocketPathPrefix, dbgSocketPathRem);
return {};
}
if (!fd.setFlags(fd.getFlags() | FD_CLOEXEC)) {
Debug::log(ERR, "Failed to set flags for socket {}{}", dbgSocketPathPrefix, dbgSocketPathRem);
return {};
}
if (isRegularSocket)
unlink(addr->sun_path);
if (bind(fd.get(), (struct sockaddr*)addr, size) < 0) {
Debug::log(ERR, "Failed to bind socket {}{}", dbgSocketPathPrefix, dbgSocketPathRem);
if (isRegularSocket)
unlink(addr->sun_path);
return {};
}
// Required for the correct functioning of `xhost` #9574
// The operation is safe because XWayland controls socket access by itself
// and rejects connections not matched by the `xhost` ACL
if (isRegularSocket && chmod(addr->sun_path, 0666) < 0) {
// We are only extending the default permissions,
// and I don't see the reason to make a full stop in case of a failed operation.
Debug::log(ERR, "Failed to set permission mode for socket {}{}", dbgSocketPathPrefix, dbgSocketPathRem);
}
if (listen(fd.get(), SOCKET_BACKLOG) < 0) {
Debug::log(ERR, "Failed to listen to socket {}{}", dbgSocketPathPrefix, dbgSocketPathRem);
if (isRegularSocket)
unlink(addr->sun_path);
return {};
}
return fd;
}
static bool checkPermissionsForSocketDir() {
struct stat buf;
if (lstat("/tmp/.X11-unix", &buf)) {
Debug::log(ERR, "Failed to stat X11 socket dir");
return false;
}
if (!(buf.st_mode & S_IFDIR)) {
Debug::log(ERR, "X11 socket dir is not a directory");
return false;
}
if ((buf.st_uid != 0) && (buf.st_uid != getuid())) {
Debug::log(ERR, "X11 socket dir is not owned by root or current user");
return false;
}
if (!(buf.st_mode & S_ISVTX)) {
if ((buf.st_mode & (S_IWGRP | S_IWOTH))) {
Debug::log(ERR, "X11 socket dir is writable by others");
return false;
}
}
return true;
}
static bool ensureSocketDirExists() {
if (mkdir("/tmp/.X11-unix", SOCKET_DIR_PERMISSIONS) != 0) {
if (errno == EEXIST)
return checkPermissionsForSocketDir();
else {
Debug::log(ERR, "XWayland: Couldn't create socket dir");
return false;
}
}
return true;
}
static std::string getSocketPath(int display, bool isLinux) {
if (isLinux)
return std::format("/tmp/.X11-unix/X{}", display);
return std::format("/tmp/.X11-unix/X{}_", display);
}
static bool openSockets(std::array<CFileDescriptor, 2>& sockets, int display) {
static auto CREATEABSTRACTSOCKET = CConfigValue<Hyprlang::INT>("xwayland:create_abstract_socket");
if (!ensureSocketDirExists())
return false;
sockaddr_un addr = {.sun_family = AF_UNIX};
std::string path;
#ifdef __linux__
if (*CREATEABSTRACTSOCKET) {
// cursed...
// but is kept as an option for better compatibility
addr.sun_path[0] = 0;
path = getSocketPath(display, true);
strncpy(addr.sun_path + 1, path.c_str(), path.length() + 1);
} else {
path = getSocketPath(display, false);
strncpy(addr.sun_path, path.c_str(), path.length() + 1);
}
#else
if (*CREATEABSTRACTSOCKET) {
Debug::log(WARN, "The abstract XWayland Unix domain socket might be used only on Linux systems. A regular one'll be created insted.");
}
path = getSocketPath(display, false);
strncpy(addr.sun_path, path.c_str(), path.length() + 1);
#endif
sockets[0] = CFileDescriptor{createSocket(&addr, path.length())};
if (!sockets[0].isValid())
return false;
path = getSocketPath(display, true);
strncpy(addr.sun_path, path.c_str(), path.length() + 1);
sockets[1] = CFileDescriptor{createSocket(&addr, path.length())};
if (!sockets[1].isValid()) {
sockets[0].reset();
return false;
}
return true;
}
static void startServer(void* data) {
if (!g_pXWayland->m_server->start())
Debug::log(ERR, "The XWayland server could not start! XWayland will not work...");
}
static int xwaylandReady(int fd, uint32_t mask, void* data) {
return g_pXWayland->m_server->ready(fd, mask);
}
static bool safeRemove(const std::string& path) {
try {
return std::filesystem::remove(path);
} catch (const std::exception& e) { Debug::log(ERR, "[XWayland] Failed to remove {}", path); }
return false;
}
bool CXWaylandServer::tryOpenSockets() {
for (size_t i = 0; i <= MAX_SOCKET_RETRIES; ++i) {
std::string lockPath = std::format("/tmp/.X{}-lock", i);
CFileDescriptor fd{open(lockPath.c_str(), O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC, LOCK_FILE_MODE)};
if (fd.isValid()) {
// we managed to open the lock
if (!openSockets(m_xFDs, i)) {
safeRemove(lockPath);
continue;
}
const std::string pidStr = std::to_string(getpid());
if (write(fd.get(), pidStr.c_str(), pidStr.length()) != (long)pidStr.length()) {
safeRemove(lockPath);
continue;
}
m_display = i;
m_displayName = std::format(":{}", m_display);
break;
}
fd = CFileDescriptor{open(lockPath.c_str(), O_RDONLY | O_CLOEXEC)};
if (!fd.isValid())
continue;
char pidstr[12] = {0};
read(fd.get(), pidstr, sizeof(pidstr) - 1);
int32_t pid = 0;
try {
pid = std::stoi(std::string{pidstr, 11});
} catch (...) { continue; }
if (kill(pid, 0) != 0 && errno == ESRCH) {
if (!safeRemove(lockPath))
continue;
i--;
}
}
if (m_display < 0) {
Debug::log(ERR, "Failed to find a suitable socket for XWayland");
return false;
}
Debug::log(LOG, "XWayland found a suitable display socket at DISPLAY: {}", m_displayName);
return true;
}
CXWaylandServer::CXWaylandServer() {
;
}
CXWaylandServer::~CXWaylandServer() {
die();
if (m_display < 0)
return;
std::string lockPath = std::format("/tmp/.X{}-lock", m_display);
safeRemove(lockPath);
std::string path;
for (bool isLinux : {true, false}) {
path = getSocketPath(m_display, isLinux);
safeRemove(path);
}
}
void CXWaylandServer::die() {
if (m_display < 0)
return;
if (m_xFDReadEvents[0]) {
wl_event_source_remove(m_xFDReadEvents[0]);
wl_event_source_remove(m_xFDReadEvents[1]);
m_xFDReadEvents = {nullptr, nullptr};
}
if (m_pipeSource)
wl_event_source_remove(m_pipeSource);
// possible crash. Better to leak a bit.
//if (xwaylandClient)
// wl_client_destroy(xwaylandClient);
m_xwaylandClient = nullptr;
}
bool CXWaylandServer::create() {
if (!tryOpenSockets())
return false;
setenv("DISPLAY", m_displayName.c_str(), true);
// TODO: lazy mode
m_idleSource = wl_event_loop_add_idle(g_pCompositor->m_wlEventLoop, ::startServer, nullptr);
return true;
}
void CXWaylandServer::runXWayland(CFileDescriptor& notifyFD) {
if (!m_xFDs[0].setFlags(m_xFDs[0].getFlags() & ~FD_CLOEXEC) || !m_xFDs[1].setFlags(m_xFDs[1].getFlags() & ~FD_CLOEXEC) ||
!m_waylandFDs[1].setFlags(m_waylandFDs[1].getFlags() & ~FD_CLOEXEC) || !m_xwmFDs[1].setFlags(m_xwmFDs[1].getFlags() & ~FD_CLOEXEC)) {
Debug::log(ERR, "Failed to unset cloexec on fds");
_exit(EXIT_FAILURE);
}
auto cmd = std::format("Xwayland {} -rootless -core -listenfd {} -listenfd {} -displayfd {} -wm {}", m_displayName, m_xFDs[0].get(), m_xFDs[1].get(), notifyFD.get(),
m_xwmFDs[1].get());
auto waylandSocket = std::format("{}", m_waylandFDs[1].get());
setenv("WAYLAND_SOCKET", waylandSocket.c_str(), true);
Debug::log(LOG, "Starting XWayland with \"{}\", bon voyage!", cmd);
execl("/bin/sh", "/bin/sh", "-c", cmd.c_str(), nullptr);
Debug::log(ERR, "XWayland failed to open");
_exit(1);
}
bool CXWaylandServer::start() {
m_idleSource = nullptr;
int wlPair[2] = {-1, -1};
if (socketpair(AF_UNIX, SOCK_STREAM, 0, wlPair) != 0) {
Debug::log(ERR, "socketpair failed (1)");
die();
return false;
}
m_waylandFDs[0] = CFileDescriptor{wlPair[0]};
m_waylandFDs[1] = CFileDescriptor{wlPair[1]};
if (!m_waylandFDs[0].setFlags(m_waylandFDs[0].getFlags() | FD_CLOEXEC) || !m_waylandFDs[1].setFlags(m_waylandFDs[1].getFlags() | FD_CLOEXEC)) {
Debug::log(ERR, "set_cloexec failed (1)");
die();
return false;
}
int xwmPair[2] = {-1, -1};
if (socketpair(AF_UNIX, SOCK_STREAM, 0, xwmPair) != 0) {
Debug::log(ERR, "socketpair failed (2)");
die();
return false;
}
m_xwmFDs[0] = CFileDescriptor{xwmPair[0]};
m_xwmFDs[1] = CFileDescriptor{xwmPair[1]};
if (!m_xwmFDs[0].setFlags(m_xwmFDs[0].getFlags() | FD_CLOEXEC) || !m_xwmFDs[1].setFlags(m_xwmFDs[1].getFlags() | FD_CLOEXEC)) {
Debug::log(ERR, "set_cloexec failed (2)");
die();
return false;
}
m_xwaylandClient = wl_client_create(g_pCompositor->m_wlDisplay, m_waylandFDs[0].get());
if (!m_xwaylandClient) {
Debug::log(ERR, "wl_client_create failed");
die();
return false;
}
m_waylandFDs[0].take(); // wl_client owns this fd now
int notify[2] = {-1, -1};
if (pipe(notify) < 0) {
Debug::log(ERR, "pipe failed");
die();
return false;
}
CFileDescriptor notifyFds[2] = {CFileDescriptor{notify[0]}, CFileDescriptor{notify[1]}};
if (!notifyFds[0].setFlags(notifyFds[0].getFlags() | FD_CLOEXEC)) {
Debug::log(ERR, "set_cloexec failed (3)");
die();
return false;
}
m_pipeSource = wl_event_loop_add_fd(g_pCompositor->m_wlEventLoop, notifyFds[0].get(), WL_EVENT_READABLE, ::xwaylandReady, nullptr);
m_pipeFd = std::move(notifyFds[0]);
auto serverPID = fork();
if (serverPID < 0) {
Debug::log(ERR, "fork failed");
die();
return false;
} else if (serverPID == 0) {
runXWayland(notifyFds[1]);
_exit(0);
}
return true;
}
int CXWaylandServer::ready(int fd, uint32_t mask) {
if (mask & WL_EVENT_READABLE) {
// xwayland writes twice
char buf[64];
ssize_t n = read(fd, buf, sizeof(buf));
if (n < 0 && errno != EINTR) {
Debug::log(ERR, "Xwayland: read from displayFd failed");
mask = 0;
} else if (n <= 0 || buf[n - 1] != '\n')
return 1;
}
// if we don't have readable here, it failed
if (!(mask & WL_EVENT_READABLE)) {
Debug::log(ERR, "Xwayland: startup failed, not setting up xwm");
g_pXWayland->m_server.reset();
return 1;
}
Debug::log(LOG, "XWayland is ready");
wl_event_source_remove(m_pipeSource);
m_pipeFd.reset();
m_pipeSource = nullptr;
// start the wm
if (!g_pXWayland->m_wm)
g_pXWayland->m_wm = makeUnique<CXWM>();
g_pCursorManager->setXWaylandCursor();
return 0;
}
#endif