[mutter/wip/wayland-work: 42/44] mutter-launch: augment with VT and TTY handling

[Giovanni Campagna <gcampagna src gnome org>]

commit 3534b5932edd97a7195de3ff68a8e3c2d63b0258
Author: Giovanni Campagna <gcampagn redhat com>
Date:   Thu Aug 22 14:34:22 2013 +0200

    mutter-launch: augment with VT and TTY handling
    
    Set the TTY mode appropriately at startup, and clean it up
    when the compositor exits. Also, take control of VT switching,
    and make sure that the compositor calls drmDropMaster when switched
    away.
    In the future, we the kernel implements the mute evdev ioctl,
    we'll also make sure that input devices are appropriately released.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=705861

 src/wayland/weston-launch.c |  186 ++++++++++++++++++++++++++++++++++++++++++-
 src/wayland/weston-launch.h |   15 +++-
 2 files changed, 196 insertions(+), 5 deletions(-)
---
diff --git a/src/wayland/weston-launch.c b/src/wayland/weston-launch.c
index c1518b4..321c6e2 100644
--- a/src/wayland/weston-launch.c
+++ b/src/wayland/weston-launch.c
@@ -46,6 +46,7 @@
 #include <termios.h>
 #include <linux/vt.h>
 #include <linux/major.h>
+#include <linux/kd.h>
 
 #include <pwd.h>
 #include <grp.h>
@@ -59,6 +60,12 @@
 
 #define MAX_ARGV_SIZE 256
 
+enum vt_state {
+       VT_HAS_VT,
+       VT_PENDING_CONFIRM,
+       VT_NOT_HAVE_VT,
+};
+
 struct weston_launch {
        struct pam_conv pc;
        pam_handle_t *ph;
@@ -72,10 +79,17 @@ struct weston_launch {
        pid_t child;
        int verbose;
        char *new_user;
+
+       struct termios terminal_attributes;
+       int kb_mode;
+       enum vt_state vt_state;
+       int expect_drop_master;
 };
 
 union cmsg_data { unsigned char b[4]; int fd; };
 
+static void quit (struct weston_launch *wl, int status);
+
 static int
 setup_launcher_socket(struct weston_launch *wl)
 {
@@ -109,6 +123,7 @@ setup_signals(struct weston_launch *wl)
        sigaddset(&mask, SIGCHLD);
        sigaddset(&mask, SIGINT);
        sigaddset(&mask, SIGTERM);
+       sigaddset(&mask, SIGUSR1);
        ret = sigprocmask(SIG_BLOCK, &mask, NULL);
        assert(ret == 0);
 
@@ -161,6 +176,11 @@ handle_setmaster(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
                ret = drmSetMaster(data->fd);
        else
                ret = drmDropMaster(data->fd);
+       if (ret == -1)
+               ret = -errno;
+
+       if (message->set_master == 0)
+               wl->expect_drop_master = 0;
 
        close(data->fd);
 
@@ -179,6 +199,70 @@ out:
 }
 
 static int
+handle_confirm_vt_switch(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
+{
+       int ret = -1;
+
+       if (wl->vt_state != VT_PENDING_CONFIRM) {
+               error(0, 0, "unexpected CONFIRM_VT_SWITCH");
+               goto out;
+       }
+
+       if (wl->expect_drop_master) {
+               error(0, 0, "drmDropMaster not called for VT switch");
+               quit(wl, 1);
+       }
+
+       wl->vt_state = VT_NOT_HAVE_VT;
+       ioctl(wl->tty, VT_RELDISP, 1);
+
+       if (wl->verbose)
+               fprintf(stderr, "weston-launcher: confirmed VT switch\n");
+
+       ret = 0;
+
+out:
+       do {
+               len = send(wl->sock[0], &ret, sizeof ret, 0);
+       } while (len < 0 && errno == EINTR);
+       if (len < 0)
+               return -1;
+
+       return 0;
+}
+
+static int
+handle_activate_vt(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
+{
+       int ret = -1;
+       struct weston_launcher_activate_vt *message;
+
+       if (len != sizeof(*message)) {
+               error(0, 0, "missing value in activate_vt request");
+               goto out;
+       }
+
+       message = msg->msg_iov->iov_base;
+
+       ret = ioctl(wl->tty, VT_ACTIVATE, message->vt);
+       if (ret < 0)
+               ret = -errno;
+
+       if (wl->verbose)
+               fprintf(stderr, "weston-launch: activate VT, ret: %d\n", ret);
+
+out:
+       do {
+               len = send(wl->sock[0], &ret, sizeof ret, 0);
+       } while (len < 0 && errno == EINTR);
+       if (len < 0)
+               return -1;
+
+       return 0;
+}
+
+
+static int
 handle_open(struct weston_launch *wl, struct msghdr *msg, ssize_t len)
 {
        int fd = -1, ret = -1;
@@ -283,19 +367,49 @@ handle_socket_msg(struct weston_launch *wl)
        case WESTON_LAUNCHER_DRM_SET_MASTER:
                ret = handle_setmaster(wl, &msg, len);
                break;
+       case WESTON_LAUNCHER_CONFIRM_VT_SWITCH:
+               ret = handle_confirm_vt_switch(wl, &msg, len);
+               break;
+       case WESTON_LAUNCHER_ACTIVATE_VT:
+               ret = handle_activate_vt(wl, &msg, len);
+               break;
        }
 
        return ret;
 }
 
 static void
+tty_reset(struct weston_launch *wl)
+{
+       struct vt_mode mode = { 0 };
+
+       if (ioctl(wl->tty, KDSKBMODE, wl->kb_mode))
+               fprintf(stderr, "failed to restore keyboard mode: %m\n");
+
+       if (ioctl(wl->tty, KDSETMODE, KD_TEXT))
+               fprintf(stderr, "failed to set KD_TEXT mode on tty: %m\n");
+
+       if (tcsetattr(wl->tty, TCSANOW, &wl->terminal_attributes) < 0)
+               fprintf(stderr, "could not restore terminal to canonical mode\n");
+
+       mode.mode = VT_AUTO;
+       if (ioctl(wl->tty, VT_SETMODE, &mode) < 0)
+               fprintf(stderr, "could not reset vt handling\n");
+}
+
+static void
 quit(struct weston_launch *wl, int status)
 {
        int err;
 
+       if (wl->child > 0)
+               kill(wl->child, SIGKILL);
+
        close(wl->signalfd);
        close(wl->sock[0]);
 
+       tty_reset(wl);
+
        if (wl->new_user) {
                err = pam_close_session(wl->ph, 0);
                if (err)
@@ -308,6 +422,32 @@ quit(struct weston_launch *wl, int status)
 }
 
 static int
+handle_vt_switch(struct weston_launch *wl)
+{
+       struct weston_launcher_message message;
+       ssize_t len;
+
+       if (wl->vt_state == VT_HAS_VT) {
+               wl->vt_state = VT_PENDING_CONFIRM;
+               wl->expect_drop_master = 1;
+               message.opcode = WESTON_LAUNCHER_SERVER_REQUEST_VT_SWITCH;
+       } else if (wl->vt_state == VT_NOT_HAVE_VT) {
+               wl->vt_state = VT_HAS_VT;
+               ioctl(wl->tty, VT_RELDISP, VT_ACKACQ);
+
+               message.opcode = WESTON_LAUNCHER_SERVER_VT_ENTER;
+       } else
+               return -1;
+
+       do {
+               len = send(wl->sock[0], &message, sizeof(message), 0);
+       } while (len < 0 && errno == EINTR);
+
+       return 0;
+}
+
+
+static int
 handle_signal(struct weston_launch *wl)
 {
        struct signalfd_siginfo sig;
@@ -343,6 +483,8 @@ handle_signal(struct weston_launch *wl)
                if (wl->child)
                        kill(wl->child, sig.ssi_signo);
                break;
+       case SIGUSR1:
+               return handle_vt_switch(wl);
        default:
                return -1;
        }
@@ -354,6 +496,8 @@ static int
 setup_tty(struct weston_launch *wl)
 {
        struct stat buf;
+       struct termios raw_attributes;
+       struct vt_mode mode = { 0 };
        char *session, *tty;
        char path[PATH_MAX];
        int ok;
@@ -365,7 +509,7 @@ setup_tty(struct weston_launch *wl)
        ok = sd_session_get_tty(session, &tty);
        if (ok == 0) {
                snprintf(path, PATH_MAX, "/dev/%s", tty);
-               wl->tty = open(path, O_RDWR | O_NOCTTY);
+               wl->tty = open(path, O_RDWR | O_NOCTTY | O_CLOEXEC);
                free(tty);
 #ifdef HAVE_SD_SESSION_GET_VT
        } else if (ok == -ENOENT) {
@@ -381,7 +525,7 @@ setup_tty(struct weston_launch *wl)
                        error(1, -ok, "could not determine current TTY");
 
                snprintf(path, PATH_MAX, "/dev/tty%s", tty);
-               wl->tty = open(path, O_RDWR | O_NOCTTY);
+               wl->tty = open(path, O_RDWR | O_NOCTTY | O_CLOEXEC);
                free(tty);
 #endif
        } else
@@ -398,6 +542,41 @@ setup_tty(struct weston_launch *wl)
 
        wl->ttynr = minor(buf.st_rdev);
 
+       if (tcgetattr(wl->tty, &wl->terminal_attributes) < 0)
+               error(1, errno, "could not get terminal attributes");
+
+       /* Ignore control characters and disable echo */
+       raw_attributes = wl->terminal_attributes;
+       cfmakeraw(&raw_attributes);
+
+       /* Fix up line endings to be normal (cfmakeraw hoses them) */
+       raw_attributes.c_oflag |= OPOST | OCRNL;
+       /* Don't generate ttou signals */
+       raw_attributes.c_oflag &= ~TOSTOP;
+
+       if (tcsetattr(wl->tty, TCSANOW, &raw_attributes) < 0)
+               error(1, errno, "could not put terminal into raw mode");
+
+       ioctl(wl->tty, KDGKBMODE, &wl->kb_mode);
+       ok = ioctl(wl->tty, KDSKBMODE, K_OFF);
+       if (ok < 0) {
+               ok = ioctl(wl->tty, KDSKBMODE, K_RAW);
+               if (ok < 0)
+                       error(1, errno, "failed to set keyboard mode on tty");
+       }
+
+       ok = ioctl(wl->tty, KDSETMODE, KD_GRAPHICS);
+       if (ok < 0)
+               error(1, errno, "failed to set KD_GRAPHICS mode on tty");
+
+       wl->vt_state = VT_HAS_VT;
+       mode.mode = VT_PROCESS;
+       mode.relsig = SIGUSR1;
+       mode.acqsig = SIGUSR1;
+       ok = ioctl(wl->tty, VT_SETMODE, &mode);
+       if (ok < 0)
+               error(1, errno, "failed to take control of vt handling");
+
        return 0;
 }
 
@@ -425,7 +604,6 @@ launch_compositor(struct weston_launch *wl, int argc, char *argv[])
 
        drop_privileges(wl);
 
-       setenv_fd("WESTON_TTY_FD", wl->tty);
        setenv_fd("WESTON_LAUNCHER_SOCK", wl->sock[1]);
        setenv("LD_LIBRARY_PATH", LIBDIR, 1);
        unsetenv("DISPLAY");
@@ -435,6 +613,7 @@ launch_compositor(struct weston_launch *wl, int argc, char *argv[])
        sigaddset(&mask, SIGTERM);
        sigaddset(&mask, SIGCHLD);
        sigaddset(&mask, SIGINT);
+       sigaddset(&mask, SIGUSR1);
        sigprocmask(SIG_UNBLOCK, &mask, NULL);
 
        snprintf (command, PATH_MAX, "%s \"$ \"", argv[0]);
@@ -514,7 +693,6 @@ main(int argc, char *argv[])
                launch_compositor(&wl, argc - optind, argv + optind);
 
        close(wl.sock[1]);
-       close(wl.tty);
 
        while (1) {
                struct pollfd fds[2];
diff --git a/src/wayland/weston-launch.h b/src/wayland/weston-launch.h
index 5be013e..81211d9 100644
--- a/src/wayland/weston-launch.h
+++ b/src/wayland/weston-launch.h
@@ -1,5 +1,6 @@
 /*
  * Copyright © 2012 Benjamin Franzke
+ *             2013 Red Hat, Inc.
  *
  * Permission to use, copy, modify, distribute, and sell this software and
  * its documentation for any purpose is hereby granted without fee, provided
@@ -25,7 +26,14 @@
 
 enum weston_launcher_opcode {
        WESTON_LAUNCHER_OPEN,
-       WESTON_LAUNCHER_DRM_SET_MASTER
+       WESTON_LAUNCHER_DRM_SET_MASTER,
+       WESTON_LAUNCHER_ACTIVATE_VT,
+       WESTON_LAUNCHER_CONFIRM_VT_SWITCH, 
+};
+
+enum weston_launcher_server_opcode {
+       WESTON_LAUNCHER_SERVER_REQUEST_VT_SWITCH,
+       WESTON_LAUNCHER_SERVER_VT_ENTER,
 };
 
 struct weston_launcher_message {
@@ -43,4 +51,9 @@ struct weston_launcher_set_master {
        int set_master;
 };
 
+struct weston_launcher_activate_vt {
+       struct weston_launcher_message header;
+       int vt;
+};
+
 #endif