[CRIU] [PATCH] tty: add vt support

Cyrill Gorcunov gorcunov at gmail.com
Fri Dec 5 01:05:39 PST 2014


On Fri, Dec 05, 2014 at 01:44:22AM +0200, Ruslan Kuprieiev wrote:
> /dev/ttyN are the virtual terminals which are provided
> by the system with major 4 and minor 0..63.
> You can run some program on ttyN by pressing alt+ctrl+FN
> and running it manualy or by using open(openvt nowadays). 
> 
> Signed-off-by: Ruslan Kuprieiev <kupruser at gmail.com>
> ---
>  include/tty.h      |  9 ++++++++
>  protobuf/tty.proto |  1 +
>  tty.c              | 62 ++++++++++++++++++++++++++++++++++++++++++++----------
>  3 files changed, 61 insertions(+), 11 deletions(-)
> 
> diff --git a/include/tty.h b/include/tty.h
> index a3026f6..5019dcf 100644
> --- a/include/tty.h
> +++ b/include/tty.h
> @@ -13,6 +13,7 @@ enum {
>  	TTY_TYPE_PTM		= 1,
>  	TTY_TYPE_PTS		= 2,
>  	TTY_TYPE_CONSOLE	= 3,
> +	TTY_TYPE_VT		= 4,
>  
>  	TTY_TYPE_MAX
>  };
> @@ -34,6 +35,14 @@ static inline int tty_type(int major, int minor)
>  		else if (minor == 1)
>  			return TTY_TYPE_CONSOLE;
>  		break;
> +	case TTY_MAJOR:
> +		if (minor < 64)
> +			/*
> +			 * Beyond 63 are the serial devices.
> +			 * Not sure how to handle them, so lets
> +			 * leave them till someone requests.
> +			 */
> +			return TTY_TYPE_VT;

This should be something like that

			/*
			 * Minors [1; MAX_NR_CONSOLES] stand for
			 * consoles (virtual terminals, VT in terms
			 * of kernel).
			 */

Also MAX_NR_CONSOLES is defined in uapi/vt.h thus we should inlcude it
directly

#include <linux/vt.h>

or (if this is a problem for some reason -- predefine own MAX_NR_CONSOLES).

>  	case UNIX98_PTY_MASTER_MAJOR ... (UNIX98_PTY_MASTER_MAJOR + UNIX98_PTY_MAJOR_COUNT - 1):
>  		return TTY_TYPE_PTM;
>  	case UNIX98_PTY_SLAVE_MAJOR:
> diff --git a/protobuf/tty.proto b/protobuf/tty.proto
> index 18470a9..0e67e85 100644
> --- a/protobuf/tty.proto
> +++ b/protobuf/tty.proto
> @@ -27,6 +27,7 @@ enum TtyType {
>  	UNKNOWN		= 0;
>  	PTY		= 1;
>  	CONSOLE		= 2;
> +	VT		= 3;
>  }
>  
>  message tty_info_entry {
> diff --git a/tty.c b/tty.c
> index b076f06..5886dff 100644
> --- a/tty.c
> +++ b/tty.c
> @@ -118,6 +118,7 @@ static LIST_HEAD(all_ttys);
>  #define MAX_TTYS	1024
>  #define MAX_PTY_INDEX	1000
>  #define CONSOLE_INDEX	1002
> +#define VT_INDEX	1004
>  
>  static DECLARE_BITMAP(tty_bitmap, (MAX_TTYS << 1));
>  static DECLARE_BITMAP(tty_active_pairs, (MAX_TTYS << 1));
> @@ -235,11 +236,17 @@ static int parse_tty_index(u32 id, int lfd, const struct fd_parms *p, int type)
>  	case TTY_TYPE_CONSOLE:
>  		index = CONSOLE_INDEX;
>  		break;
> +
> +	case TTY_TYPE_VT: {
> +		index = VT_INDEX;
> +		break;
> +	}

Redundant { } here

>  	default:
>  		BUG();
>  	}
>  
>  	if (type != TTY_TYPE_CONSOLE &&
> +	    type != TTY_TYPE_VT &&
>  	    index > MAX_PTY_INDEX) {
>  		pr_err("Index %d on tty %x is too big\n", index, id);
>  		return -1;
> @@ -508,6 +515,13 @@ static int tty_restore_ctl_terminal(struct file_desc *d, int fd)
>  			pr_perror("Can't open %s", path_from_reg(info->reg_d));
>  			goto err;
>  		}
> +	} else if (info->type == TTY_TYPE_VT) {
> +		slave = open_pty_reg(info->reg_d, O_RDONLY);
> +		index = VT_INDEX;
> +		if (slave < 0) {
> +			pr_perror("Can't open %s", path_from_reg(info->reg_d));
> +			goto err;
> +		}
>  	} else
>  		BUG();
>  
> @@ -534,13 +548,21 @@ static char *tty_name(int type)
>  		return "pts";
>  	case TTY_TYPE_CONSOLE:
>  		return "console";
> +	case TTY_TYPE_VT:
> +		return "tty";
>  	}
>  	return "unknown";
>  }
>  
>  static bool tty_is_master(struct tty_info *info)
>  {
> -	return info->type == TTY_TYPE_PTM || info->type == TTY_TYPE_CONSOLE;
> +	if (info->type == TTY_TYPE_PTM || info->type == TTY_TYPE_CONSOLE)
> +		return true;
> +
> +	if (info->type == TTY_TYPE_VT && !opts.shell_job)
> +		return true;
> +
> +	return false;
>  }
>  
>  static bool tty_is_hung(struct tty_info *info)
> @@ -558,9 +580,21 @@ static bool tty_has_active_pair(struct tty_info *info)
>  
>  static void tty_show_pty_info(char *prefix, struct tty_info *info)
>  {
> +	int index;

	int index = -1;

> +
> +	switch (info->type) {
> +	case TTY_TYPE_CONSOLE:
> +		index = CONSOLE_INDEX;
> +		break;
> +	case TTY_TYPE_VT:
> +		index = VT_INDEX;
> +		break;

	case TTY_TYPE_PTM:
	case TTY_TYPE_PTS:
		index = info->tie->pty->index;
		break;

> +	default:
> +		index = info->tie->pty->index;
> +	}

drop this "default"

> +
>  	pr_info("%s type %s id %#x index %d (master %d sid %d pgrp %d inherit %d)\n",
> -		prefix, tty_name(info->type), info->tfe->id,
> -		info->type == TTY_TYPE_CONSOLE ? CONSOLE_INDEX : info->tie->pty->index,
> +		prefix, tty_name(info->type), info->tfe->id, index,
>  		tty_is_master(info), info->tie->sid, info->tie->pgrp, info->inherit);
>  }
>  
> @@ -788,14 +822,15 @@ err:
>  	return -1;
>  }
>  
> -static int open_console(struct tty_info *info)
> +static int open_simple_tty(struct tty_info *info)
>  {
>  	int fd = -1;
>  
>  	fd = open_pty_reg(info->reg_d, info->tfe->flags);
>  	if (fd < 0) {
> -		pr_perror("Can't open console %x",
> -			  info->tfe->id);
> +		pr_perror("Can't open %s %x",
> +		info->type == TTY_TYPE_CONSOLE ? "console" : "virtual terminal",
> +		info->tfe->id);
>  		return -1;
>  	}
>  
> @@ -820,8 +855,8 @@ static int tty_open(struct file_desc *d)
>  	if (!tty_is_master(info))
>  		return pty_open_unpaired_slave(d, info);
>  
> -	if (info->type == TTY_TYPE_CONSOLE)
> -		return open_console(info);
> +	if (info->type == TTY_TYPE_CONSOLE || info->type == TTY_TYPE_VT)
> +		return open_simple_tty(info);

This should be somehow cleaned up, I'll think on it, but lets leave it as
in patch for now

>  
>  	return pty_open_ptmx(info);
>  }
> @@ -1002,12 +1037,12 @@ int tty_setup_slavery(void)
>  	list_for_each_entry(info, &all_ttys, list) {
>  		if (tty_find_restoring_task(info))
>  			return -1;
> -		if (info->type == TTY_TYPE_CONSOLE)
> +		if (info->type == TTY_TYPE_CONSOLE || info->type == TTY_TYPE_VT)
>  			continue;
>  
>  		peer = info;
>  		list_for_each_entry_safe_continue(peer, m, &all_ttys, list) {
> -			if (peer->type == TTY_TYPE_CONSOLE)
> +			if (peer->type == TTY_TYPE_CONSOLE || info->type == TTY_TYPE_VT)
>  				continue;
>  			if (peer->tie->pty->index != info->tie->pty->index)
>  				continue;
> @@ -1057,7 +1092,8 @@ static int verify_info(struct tty_info *info)
>  {
>  	if (info->type != TTY_TYPE_PTM &&
>  	    info->type != TTY_TYPE_PTS &&
> -	    info->type != TTY_TYPE_CONSOLE) {
> +	    info->type != TTY_TYPE_CONSOLE &&
> +	    info->type != TTY_TYPE_VT) {
>  		pr_err("Unknown type %d master peer %x\n",
>  		       info->type, info->tfe->id);
>  		return -1;
> @@ -1115,6 +1151,7 @@ static int collect_one_tty_info_entry(void *obj, ProtobufCMessage *msg)
>  		}
>  		break;
>  	case TTY_TYPE__CONSOLE:
> +	case TTY_TYPE__VT:
>  		if (info->tie->pty) {
>  			pr_err("PTY data found (id %x), corrupted image?\n",
>  			       info->tie->id);
> @@ -1312,6 +1349,9 @@ static int dump_tty_info(int lfd, u32 id, const struct fd_parms *p, int type, in
>  	case TTY_TYPE_CONSOLE:
>  		info.type	= TTY_TYPE__CONSOLE;
>  		break;
> +	case TTY_TYPE_VT:
> +		info.type	= TTY_TYPE__VT;
> +		break;
>  	default:
>  		BUG();
>  	}

The rest looks good to me, hopefully it works as needed (some zdtm tests?).
But I didn't look into kernel implementatio so might be missing something.

	Cyrill


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