diff options
| -rw-r--r-- | xwayland/server.c | 91 |
1 files changed, 37 insertions, 54 deletions
diff --git a/xwayland/server.c b/xwayland/server.c index 1f8f9feb..e0cf5aa5 100644 --- a/xwayland/server.c +++ b/xwayland/server.c @@ -25,7 +25,8 @@ static void safe_close(int fd) { } } -noreturn static void exec_xwayland(struct wlr_xwayland_server *server) { +noreturn static void exec_xwayland(struct wlr_xwayland_server *server, + int notify_fd) { if (!set_cloexec(server->x_fd[0], false) || !set_cloexec(server->x_fd[1], false) || !set_cloexec(server->wl_fd[1], false)) { @@ -37,16 +38,13 @@ noreturn static void exec_xwayland(struct wlr_xwayland_server *server) { _exit(EXIT_FAILURE); } - /* Make Xwayland signal us when it's ready */ - /* TODO: can we use -displayfd instead? */ - signal(SIGUSR1, SIG_IGN); - char *argv[64] = {0}; size_t i = 0; - char listenfd0[16], listenfd1[16]; + char listenfd0[16], listenfd1[16], displayfd[16]; snprintf(listenfd0, sizeof(listenfd0), "%d", server->x_fd[0]); snprintf(listenfd1, sizeof(listenfd1), "%d", server->x_fd[1]); + snprintf(displayfd, sizeof(displayfd), "%d", notify_fd); argv[i++] = "Xwayland"; argv[i++] = server->display_name; @@ -65,6 +63,8 @@ noreturn static void exec_xwayland(struct wlr_xwayland_server *server) { argv[i++] = "-listen"; argv[i++] = listenfd1; #endif + argv[i++] = "-displayfd"; + argv[i++] = displayfd; char wmfd[16]; if (server->options.enable_wm) { @@ -219,36 +219,44 @@ static void handle_display_destroy(struct wl_listener *listener, void *data) { } static int xserver_handle_ready(int fd, uint32_t mask, void *data) { - // There are three ways in which we can end up here, from server_start: - // 1. the second fork failed - // 2. the exec failed - // 3. Xwayland sent a SIGUSR1 - // - // All three cases result in a write to the pipe, which triggers us. - // - // For the first two cases, the first fork will exit with - // EXIT_FAILURE, notifying us that startup failed. - // - // For the third case, the first fork will exit with EXIT_SUCCESS - // and we'll know that Xwayland started successfully. - - close(fd); struct wlr_xwayland_server *server = data; - int stat_val = -1; - while (waitpid(server->pid, &stat_val, 0) < 0) { + if (mask & WL_EVENT_READABLE) { + /* Xwayland writes to the pipe twice, so if we close it too early + * it's possible the second write will fail and Xwayland shuts down. + * Make sure we read until end of line marker to avoid this. + */ + char buf[64]; + ssize_t n = read(fd, buf, sizeof(buf)); + if (n < 0 && errno != EINTR) { + /* Clear mask to signal start failure after reaping child */ + wlr_log_errno(WLR_ERROR, "read from Xwayland display_fd failed"); + mask = 0; + } else if (n <= 0 || buf[n-1] != '\n') { + /* Returning 1 here means recheck and call us again if required. */ + return 1; + } + } + + while (waitpid(server->pid, NULL, 0) < 0) { if (errno == EINTR) { continue; } wlr_log_errno(WLR_ERROR, "waitpid for Xwayland fork failed"); goto error; } - if (stat_val) { + /* Xwayland will only write on the fd once it has finished its + * initial setup. Getting an event here without READABLE means + * the server end failed. + */ + if (!(mask & WL_EVENT_READABLE)) { + assert(mask & WL_EVENT_HANGUP); wlr_log(WLR_ERROR, "Xwayland startup failed, not setting up xwm"); goto error; } wlr_log(WLR_DEBUG, "Xserver is ready"); + close(fd); wl_event_source_remove(server->pipe_source); server->pipe_source = NULL; @@ -258,13 +266,15 @@ static int xserver_handle_ready(int fd, uint32_t mask, void *data) { }; wlr_signal_emit_safe(&server->events.ready, &event); - return 1; /* wayland event loop dispatcher's count */ + /* We removed the source, so don't need recheck */ + return 0; error: /* clean up */ + close(fd); server_finish_process(server); server_finish_display(server); - return 1; + return 0; } static bool server_start_display(struct wlr_xwayland_server *server, @@ -329,7 +339,7 @@ static bool server_start(struct wlr_xwayland_server *server) { server_finish_process(server); return false; } - if (!set_cloexec(notify_fd[1], true) || !set_cloexec(notify_fd[0], true)) { + if (!set_cloexec(notify_fd[0], true)) { wlr_log(WLR_ERROR, "Failed to set CLOEXEC on FD"); server_finish_process(server); return false; @@ -347,39 +357,12 @@ static bool server_start(struct wlr_xwayland_server *server) { server_finish_process(server); return false; } else if (server->pid == 0) { - /* Double-fork, but we need to forward SIGUSR1 once Xserver(1) - * is ready, or error if there was one. */ - close(notify_fd[0]); - sigset_t sigset; - sigemptyset(&sigset); - sigaddset(&sigset, SIGUSR1); - sigaddset(&sigset, SIGCHLD); - sigprocmask(SIG_BLOCK, &sigset, NULL); - pid_t pid = fork(); if (pid < 0) { wlr_log_errno(WLR_ERROR, "second fork failed"); - (void)!write(notify_fd[1], "\n", 1); _exit(EXIT_FAILURE); } else if (pid == 0) { - exec_xwayland(server); - } - - int sig; - sigwait(&sigset, &sig); - if (write(notify_fd[1], "\n", 1) < 1) { - // Note: if this write failed and we've leaked the write - // end of the pipe (due to a race between another thread - // exec'ing and our call to fcntl), then our handler will - // never wake up and never notice this failure. Hopefully - // that combination of events is extremely unlikely. This - // applies to the other write, too. - wlr_log_errno(WLR_ERROR, "write to pipe failed"); - _exit(EXIT_FAILURE); - } - if (sig == SIGCHLD) { - waitpid(pid, NULL, 0); - _exit(EXIT_FAILURE); + exec_xwayland(server, notify_fd[1]); } _exit(EXIT_SUCCESS); |