[PATCH v2] weston-launch: Fixed TTY switching

[Bryce Harrington]

On Thu, Apr 09, 2015 at 04:11:17PM +0100, mateuszx.potrola at intel.com wrote:
> From: Mateusz Polrola <mateuszx.potrola at intel.com>
> 
> After weston-launch is executing weston it cannot close TTY file,
> because it is still required to properly handle SIGUSR1 and SIGUSR2
> signals that are used for switching TTY.
> 
> Additionally after opening TTY it has to be activated, so that user
> don't have to manually switch to TTY used by weston first to be able to switch
> to other TTY.
> During shutdown TTY file has to be reopened, as device was already deinitialize by child
> process, but it is still required to cleanup VT handling and leave
> system in sane state.
> 
> Changes since v1:
> - Use snprintf to copy tty filename and check for truncation
> - Checking for errors of VT_ACTIVATE ioctl call
> - Removed VT_WAITACTIVATE ioctl call
> 
> Signed-off-by: Mateusz Polrola <mateuszx.potrola at intel.com>

Reviewed-by: Bryce Harrington <bryce at osg.samsung.com>

Anyone else want to comment on this?  If not, I'll pull this one to
include 1.8 next week.

> ---
>  src/weston-launch.c |   23 ++++++++++++++++++++---
>  1 files changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/src/weston-launch.c b/src/weston-launch.c
> index 10c66de..fb46c6e 100644
> --- a/src/weston-launch.c
> +++ b/src/weston-launch.c
> @@ -46,6 +46,7 @@
>  #include <linux/vt.h>
>  #include <linux/major.h>
>  #include <linux/kd.h>
> +#include <linux/limits.h>
>  
>  #include <pwd.h>
>  #include <grp.h>
> @@ -105,6 +106,7 @@ struct weston_launch {
>  	pid_t child;
>  	int verbose;
>  	char *new_user;
> +	char tty_path[PATH_MAX];
>  };
>  
>  union cmsg_data { unsigned char b[4]; int fd; };
> @@ -419,6 +421,13 @@ quit(struct weston_launch *wl, int status)
>  		pam_end(wl->ph, err);
>  	}
>  
> +	/* tty will be deinitialized by child process, so it has to be
> +	 * opened again to correctly cleanup vt handling. */
> +	if (wl->tty != STDIN_FILENO) {
> +		close(wl->tty);
> +		wl->tty = open(wl->tty_path, O_RDWR | O_NOCTTY);
> +	}
> +
>  	if (ioctl(wl->tty, KDSKBMUTE, 0) &&
>  	    ioctl(wl->tty, KDSKBMODE, wl->kb_mode))
>  		fprintf(stderr, "failed to restore keyboard mode: %m\n");
> @@ -521,8 +530,12 @@ setup_tty(struct weston_launch *wl, const char *tty)
>  		t = ttyname(STDIN_FILENO);
>  		if (t && strcmp(t, tty) == 0)
>  			wl->tty = STDIN_FILENO;
> -		else
> +		else {
>  			wl->tty = open(tty, O_RDWR | O_NOCTTY);
> +			strcpy(wl->tty_path, tty);
> +			if (snprintf(wl->tty_path, PATH_MAX, "%s", tty) >= PATH_MAX)
> +				error(1, 0, "tty filename too long");
> +		}
>  	} else {
>  		int tty0 = open("/dev/tty0", O_WRONLY | O_CLOEXEC);
>  		char filename[16];
> @@ -536,6 +549,8 @@ setup_tty(struct weston_launch *wl, const char *tty)
>  		snprintf(filename, sizeof filename, "/dev/tty%d", wl->ttynr);
>  		wl->tty = open(filename, O_RDWR | O_NOCTTY);
>  		close(tty0);
> +		if (snprintf(wl->tty_path, PATH_MAX, "%s", filename) >= PATH_MAX)
> +			error(1, 0, "tty filename too long");
>  	}
>  
>  	if (wl->tty < 0)
> @@ -555,6 +570,10 @@ setup_tty(struct weston_launch *wl, const char *tty)
>  		wl->ttynr = minor(buf.st_rdev);
>  	}
>  
> +	/* Activate tty, otherwise tty switches won't work right away. */
> +	if (ioctl(wl->tty, VT_ACTIVATE, wl->ttynr))
> +		error(1, errno, "failed to activate tty: %m\n");
> +
>  	if (ioctl(wl->tty, KDGKBMODE, &wl->kb_mode))
>  		error(1, errno, "failed to get current keyboard mode: %m\n");
>  
> @@ -744,8 +763,6 @@ main(int argc, char *argv[])
>  		launch_compositor(&wl, argc - optind, argv + optind);
>  
>  	close(wl.sock[1]);
> -	if (wl.tty != STDIN_FILENO)
> -		close(wl.tty);
>  
>  	while (1) {
>  		struct pollfd fds[2];
> -- 
> 1.7.7.6
> 
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