+ pid = fork();
+ if (pid < 0) {
+ perror("pterm: fork");
+ exit(1);
+ } else if (pid == 0) {
+ char display[128], buffer[128];
+ int dlen, ret;
+
+ close(pipefd[1]);
+ /*
+ * Now sit here until we receive a display name from the
+ * other end of the pipe, and then stamp utmp. Unstamp utmp
+ * again, and exit, when the pipe closes.
+ */
+
+ dlen = 0;
+ while (1) {
+
+ ret = read(pipefd[0], buffer, lenof(buffer));
+ if (ret <= 0) {
+ cleanup_utmp();
+ _exit(0);
+ } else if (!pty_stamped_utmp) {
+ if (dlen < lenof(display))
+ memcpy(display+dlen, buffer,
+ min(ret, lenof(display)-dlen));
+ if (buffer[ret-1] == '\0') {
+ /*
+ * Now we have a display name. NUL-terminate
+ * it, and stamp utmp.
+ */
+ display[lenof(display)-1] = '\0';
+ /*
+ * Trap as many fatal signals as we can in the
+ * hope of having the best possible chance to
+ * clean up utmp before termination. We are
+ * unfortunately unprotected against SIGKILL,
+ * but that's life.
+ */
+ putty_signal(SIGHUP, fatal_sig_handler);
+ putty_signal(SIGINT, fatal_sig_handler);
+ putty_signal(SIGQUIT, fatal_sig_handler);
+ putty_signal(SIGILL, fatal_sig_handler);
+ putty_signal(SIGABRT, fatal_sig_handler);
+ putty_signal(SIGFPE, fatal_sig_handler);
+ putty_signal(SIGPIPE, fatal_sig_handler);
+ putty_signal(SIGALRM, fatal_sig_handler);
+ putty_signal(SIGTERM, fatal_sig_handler);
+ putty_signal(SIGSEGV, fatal_sig_handler);
+ putty_signal(SIGUSR1, fatal_sig_handler);
+ putty_signal(SIGUSR2, fatal_sig_handler);
+#ifdef SIGBUS
+ putty_signal(SIGBUS, fatal_sig_handler);
+#endif
+#ifdef SIGPOLL
+ putty_signal(SIGPOLL, fatal_sig_handler);
+#endif
+#ifdef SIGPROF
+ putty_signal(SIGPROF, fatal_sig_handler);
+#endif
+#ifdef SIGSYS
+ putty_signal(SIGSYS, fatal_sig_handler);
+#endif
+#ifdef SIGTRAP
+ putty_signal(SIGTRAP, fatal_sig_handler);
+#endif
+#ifdef SIGVTALRM
+ putty_signal(SIGVTALRM, fatal_sig_handler);
+#endif
+#ifdef SIGXCPU
+ putty_signal(SIGXCPU, fatal_sig_handler);
+#endif
+#ifdef SIGXFSZ
+ putty_signal(SIGXFSZ, fatal_sig_handler);
+#endif
+#ifdef SIGIO
+ putty_signal(SIGIO, fatal_sig_handler);
+#endif
+ setup_utmp(pty_name, display);
+ }
+ }
+ }
+ } else {
+ close(pipefd[0]);
+ pty_utmp_helper_pid = pid;
+ pty_utmp_helper_pipe = pipefd[1];
+ }
+#endif
+
+ /* Drop privs. */
+ {
+#ifndef HAVE_NO_SETRESUID
+ int gid = getgid(), uid = getuid();
+ int setresgid(gid_t, gid_t, gid_t);
+ int setresuid(uid_t, uid_t, uid_t);
+ setresgid(gid, gid, gid);
+ setresuid(uid, uid, uid);
+#else
+ setgid(getgid());
+ setuid(getuid());
+#endif
+ }
+}
+
+int pty_select_result(int fd, int event)
+{
+ char buf[4096];
+ int ret;
+ int finished = FALSE;
+
+ if (fd == pty_master_fd && event == 1) {
+
+ ret = read(pty_master_fd, buf, sizeof(buf));
+
+ /*
+ * Clean termination condition is that either ret == 0, or ret
+ * < 0 and errno == EIO. Not sure why the latter, but it seems
+ * to happen. Boo.
+ */
+ if (ret == 0 || (ret < 0 && errno == EIO)) {
+ /*
+ * We assume a clean exit if the pty has closed but the
+ * actual child process hasn't. The only way I can
+ * imagine this happening is if it detaches itself from
+ * the pty and goes daemonic - in which case the
+ * expected usage model would precisely _not_ be for
+ * the pterm window to hang around!
+ */
+ finished = TRUE;
+ if (!pty_child_dead)
+ pty_exit_code = 0;
+ } else if (ret < 0) {
+ perror("read pty master");
+ exit(1);
+ } else if (ret > 0) {
+ from_backend(pty_frontend, 0, buf, ret);
+ }
+ } else if (fd == pty_signal_pipe[0]) {
+ pid_t pid;
+ int status;
+ char c[1];
+
+ read(pty_signal_pipe[0], c, 1); /* ignore its value; it'll be `x' */
+
+ do {
+ pid = waitpid(-1, &status, WNOHANG);
+ if (pid == pty_child_pid &&
+ (WIFEXITED(status) || WIFSIGNALED(status))) {
+ /*
+ * The primary child process died. We could keep
+ * the terminal open for remaining subprocesses to
+ * output to, but conventional wisdom seems to feel
+ * that that's the Wrong Thing for an xterm-alike,
+ * so we bail out now (though we don't necessarily
+ * _close_ the window, depending on the state of
+ * Close On Exit). This would be easy enough to
+ * change or make configurable if necessary.
+ */
+ pty_exit_code = status;
+ pty_child_dead = TRUE;
+ finished = TRUE;
+ }
+ } while(pid > 0);
+ }
+
+ if (finished && !pty_finished) {
+ uxsel_del(pty_master_fd);
+ pty_close();
+ pty_master_fd = -1;
+
+ pty_finished = TRUE;
+
+ /*
+ * This is a slight layering-violation sort of hack: only
+ * if we're not closing on exit (COE is set to Never, or to
+ * Only On Clean and it wasn't a clean exit) do we output a
+ * `terminated' message.
+ */
+ if (pty_cfg.close_on_exit == FORCE_OFF ||
+ (pty_cfg.close_on_exit == AUTO && pty_exit_code != 0)) {
+ char message[512];
+ if (WIFEXITED(pty_exit_code))
+ sprintf(message, "\r\n[pterm: process terminated with exit"
+ " code %d]\r\n", WEXITSTATUS(pty_exit_code));
+ else if (WIFSIGNALED(pty_exit_code))
+#ifdef HAVE_NO_STRSIGNAL
+ sprintf(message, "\r\n[pterm: process terminated on signal"
+ " %d]\r\n", WTERMSIG(pty_exit_code));
+#else
+ sprintf(message, "\r\n[pterm: process terminated on signal"
+ " %d (%.400s)]\r\n", WTERMSIG(pty_exit_code),
+ strsignal(WTERMSIG(pty_exit_code)));
+#endif
+ from_backend(pty_frontend, 0, message, strlen(message));
+ }
+
+ notify_remote_exit(pty_frontend);
+ }
+ return !finished;
+}
+
+static void pty_uxsel_setup(void)
+{
+ uxsel_set(pty_master_fd, 1, pty_select_result);
+ uxsel_set(pty_signal_pipe[0], 1, pty_select_result);
+}
+
+/*
+ * Called to set up the pty.
+ *
+ * Returns an error message, or NULL on success.
+ *
+ * Also places the canonical host name into `realhost'. It must be
+ * freed by the caller.
+ */
+static const char *pty_init(void *frontend, void **backend_handle, Config *cfg,
+ char *host, int port, char **realhost, int nodelay,
+ int keepalive)
+{
+ int slavefd;
+ pid_t pid, pgrp;
+ long windowid;
+
+ pty_frontend = frontend;
+ *backend_handle = NULL; /* we can't sensibly use this, sadly */
+
+ pty_cfg = *cfg; /* structure copy */
+ pty_term_width = cfg->width;
+ pty_term_height = cfg->height;
+
+ if (pty_master_fd < 0)
+ pty_open_master();
+
+ /*
+ * Set the backspace character to be whichever of ^H and ^? is
+ * specified by bksp_is_delete.
+ */
+ {
+ struct termios attrs;
+ tcgetattr(pty_master_fd, &attrs);
+ attrs.c_cc[VERASE] = cfg->bksp_is_delete ? '\177' : '\010';
+ tcsetattr(pty_master_fd, TCSANOW, &attrs);
+ }
+
+#ifndef OMIT_UTMP
+ /*
+ * Stamp utmp (that is, tell the utmp helper process to do so),
+ * or not.
+ */
+ if (!cfg->stamp_utmp) {
+ close(pty_utmp_helper_pipe); /* just let the child process die */
+ pty_utmp_helper_pipe = -1;
+ } else {
+ char *location = get_x_display(pty_frontend);
+ int len = strlen(location)+1, pos = 0; /* +1 to include NUL */
+ while (pos < len) {
+ int ret = write(pty_utmp_helper_pipe, location+pos, len - pos);
+ if (ret < 0) {
+ perror("pterm: writing to utmp helper process");
+ close(pty_utmp_helper_pipe); /* arrgh, just give up */
+ pty_utmp_helper_pipe = -1;
+ break;
+ }
+ pos += ret;
+ }
+ }
+#endif
+
+ windowid = get_windowid(pty_frontend);