[CRIU] [RFC] tty: Add support of system console (/dev/console)

Tycho Andersen tycho.andersen at canonical.com
Wed Oct 15 05:10:46 PDT 2014


Hi Cyrill,

On Wed, Oct 15, 2014 at 01:27:49PM +0400, Cyrill Gorcunov wrote:
> /dev/console is a system console which provided
> by the system with major 5 and minor 1. It's usually
> configured on system startup with console= option
> and underlied driver is resposible to deliver messages
> to the console user.
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
> ---
> 
> This patch is on top of previous
> 
> 	[PATCH 0/5] tty: Use reg-files engine to save paths to tty peers

I tried to apply both the above branch and this patch, but my git
apply failed against current master. Can you send a github branch
that I can pull?

Tycho

> please take a look.
> 
>  include/tty.h      |   1 +
>  protobuf/tty.proto |   1 +
>  tty.c              | 165 +++++++++++++++++++++++++++++++++++++++--------------
>  3 files changed, 124 insertions(+), 43 deletions(-)
> 
> diff --git a/include/tty.h b/include/tty.h
> index 7181cdd00e6c..658981304466 100644
> --- a/include/tty.h
> +++ b/include/tty.h
> @@ -10,6 +10,7 @@ enum {
>  	TTY_TYPE_UNKNOWN	= 0,
>  	TTY_TYPE_PTM		= 1,
>  	TTY_TYPE_PTS		= 2,
> +	TTY_TYPE_CONSOLE	= 3,
>  
>  	TTY_TYPE_MAX
>  };
> diff --git a/protobuf/tty.proto b/protobuf/tty.proto
> index 8942965c580b..18470a9af0b7 100644
> --- a/protobuf/tty.proto
> +++ b/protobuf/tty.proto
> @@ -26,6 +26,7 @@ message tty_pty_entry {
>  enum TtyType {
>  	UNKNOWN		= 0;
>  	PTY		= 1;
> +	CONSOLE		= 2;
>  }
>  
>  message tty_info_entry {
> diff --git a/tty.c b/tty.c
> index e5e64878a736..63b3b810bcfe 100644
> --- a/tty.c
> +++ b/tty.c
> @@ -114,7 +114,10 @@ static LIST_HEAD(all_ttys);
>   * This particular bitmap requires 256 bytes of memory.
>   * Pretty acceptable trade off in a sake of simplicity.
>   */
> -#define MAX_TTYS 1024
> +#define MAX_TTYS	1024
> +#define MAX_PTY_INDEX	1000
> +#define CONSOLE_INDEX	1002
> +
>  static DECLARE_BITMAP(tty_bitmap, (MAX_TTYS << 1));
>  static DECLARE_BITMAP(tty_active_pairs, (MAX_TTYS << 1));
>  
> @@ -229,7 +232,7 @@ static int parse_pty_index(u32 id, int lfd, const struct fd_parms *p, int type)
>  	}
>  	}
>  
> -	if (index > MAX_TTYS) {
> +	if (index > MAX_PTY_INDEX) {
>  		pr_err("Index %d on tty %x is too big\n", index, id);
>  		return -1;
>  	}
> @@ -296,6 +299,7 @@ static struct tty_info *pty_alloc_fake(struct tty_info *info, int type)
>  		 info->tfe->id, info->reg_d);
>  
>  	BUG_ON(!info->reg_d);
> +	BUG_ON((type != TTY_TYPE_PTM) && (type != TTY_TYPE_PTS));
>  	orig = container_of(info->reg_d, struct reg_file_info, d);
>  
>  	p = xzalloc(sizeof(*p)		+
> @@ -512,20 +516,29 @@ static int tty_set_prgp(int fd, int group)
>  static int tty_restore_ctl_terminal(struct file_desc *d, int fd)
>  {
>  	struct tty_info *info = container_of(d, struct tty_info, d);
> -	struct tty_info *fake;
> -	int slave, ret = -1;
> +	struct tty_info *fake = NULL;
> +	int slave = -1, ret = -1;
>  
>  	if (!is_service_fd(fd, CTL_TTY_OFF))
>  		return 0;
>  
> -	fake = pty_alloc_fake_slave(info);
> -	if (!fake)
> -		goto err;
> -	slave = open_pty_reg(fake, O_RDONLY);
> -	if (slave < 0) {
> -		pr_perror("Can't open %s", path_from_reg(fake->reg_d));
> -		goto err;
> -	}
> +	if (info->type == TTY_TYPE_PTM || info->type == TTY_TYPE_PTS) {
> +		fake = pty_alloc_fake_slave(info);
> +		if (!fake)
> +			goto err;
> +		slave = open_pty_reg(fake, O_RDONLY);
> +		if (slave < 0) {
> +			pr_perror("Can't open %s", path_from_reg(fake->reg_d));
> +			goto err;
> +		}
> +	} else if (info->type == TTY_TYPE_CONSOLE) {
> +		slave = open_pty_reg(info, O_RDONLY);
> +		if (slave < 0) {
> +			pr_perror("Can't open %s", path_from_reg(info->reg_d));
> +			goto err;
> +		}
> +	} else
> +		BUG();
>  
>  	pr_info("Restore session %d by %d tty (index %d)\n",
>  		 info->tie->sid, (int)getpid(),
> @@ -548,6 +561,8 @@ int tty_type(int major, int minor)
>  	case TTYAUX_MAJOR:
>  		if (minor == 0 || minor == 2)
>  			return TTY_TYPE_PTM;
> +		else if (minor == 1)
> +			return TTY_TYPE_CONSOLE;
>  		break;
>  	case UNIX98_PTY_MASTER_MAJOR ... (UNIX98_PTY_MASTER_MAJOR + UNIX98_PTY_MAJOR_COUNT - 1):
>  		return TTY_TYPE_PTM;
> @@ -564,13 +579,16 @@ static char *tty_name(int type)
>  		return "ptmx";
>  	case TTY_TYPE_PTS:
>  		return "pts";
> +	case TTY_TYPE_CONSOLE:
> +		return "console";
>  	}
>  	return "unknown";
>  }
>  
>  static bool tty_is_master(struct tty_info *info)
>  {
> -	return info->type == TTY_TYPE_PTM;
> +	return info->type == TTY_TYPE_PTM ||
> +		info->type == TTY_TYPE_CONSOLE;
>  }
>  
>  static bool tty_is_hung(struct tty_info *info)
> @@ -816,6 +834,26 @@ err:
>  	return -1;
>  }
>  
> +static int open_console(struct tty_info *info)
> +{
> +	int fd = -1;
> +
> +	fd = open_pty_reg(info, info->tfe->flags);
> +	if (fd < 0) {
> +		pr_perror("Can't open console %x",
> +			  info->tfe->id);
> +		return -1;
> +	}
> +
> +	if (restore_tty_params(fd, info))
> +		goto err;
> +
> +	return fd;
> +err:
> +	close_safe(&fd);
> +	return -1;
> +}
> +
>  static int tty_open(struct file_desc *d)
>  {
>  	struct tty_info *info = container_of(d, struct tty_info, d);
> @@ -828,8 +866,10 @@ static int tty_open(struct file_desc *d)
>  	if (!tty_is_master(info))
>  		return pty_open_unpaired_slave(d, info);
>  
> -	return pty_open_ptmx(info);
> -
> +	if (info->type == TTY_TYPE_CONSOLE)
> +		return open_console(info);
> +	else
> +		return pty_open_ptmx(info);
>  }
>  
>  static int tty_transport(FdinfoEntry *fe, struct file_desc *d)
> @@ -1058,8 +1098,9 @@ static int verify_termios(u32 id, TermiosEntry *e)
>  static int verify_info(struct tty_info *info)
>  {
>  	if (info->type != TTY_TYPE_PTM &&
> -	    info->type != TTY_TYPE_PTS) {
> -		pr_err("Unknown type %d master peer %x\n",
> +	    info->type != TTY_TYPE_PTS &&
> +	    info->type != TTY_TYPE_CONSOLE) {
> +		pr_err("Unknown type %d peer %x\n",
>  		       info->type, info->tfe->id);
>  		return -1;
>  	}
> @@ -1107,18 +1148,27 @@ static int collect_one_tty_info_entry(void *obj, ProtobufCMessage *msg)
>  
>  	info->tie = pb_msg(msg, TtyInfoEntry);
>  
> -	if (info->tie->type != TTY_TYPE__PTY) {
> +	switch (info->tie->type) {
> +	case TTY_TYPE__PTY:
> +		if (!info->tie->pty) {
> +			pr_err("No PTY data found (id %x), corrupted image?\n",
> +			       info->tie->id);
> +			return -1;
> +		}
> +		break;
> +	case TTY_TYPE__CONSOLE:
> +		if (info->tie->pty) {
> +			pr_err("PTY data found (id %x), corrupted image?\n",
> +			       info->tie->id);
> +			return -1;
> +		}
> +		break;
> +	default:
>  		pr_err("Unexpected TTY type %d (id %x)\n",
>  		       info->tie->type, info->tie->id);
>  		return -1;
>  	}
>  
> -	if (!info->tie->pty) {
> -		pr_err("No PTY data found (id %x), corrupted image?\n",
> -		       info->tie->id);
> -		return -1;
> -	}
> -
>  	INIT_LIST_HEAD(&info->list);
>  	list_add(&info->list, &all_tty_info_entries);
>  
> @@ -1171,10 +1221,16 @@ static int collect_one_tty(void *obj, ProtobufCMessage *msg)
>  
>  	info->reg_d = find_file_desc_raw(FD_TYPES__REG, info->tfe->id);
>  	if (!info->reg_d) {
> -		info->reg_d = pty_alloc_fake_reg_d(info, true);
> -		if (!info->reg_d) {
> -			pr_err("Can't generate new reg_d descriptor for id %#x\n",
> -			       info->tfe->id);
> +		if (info->type == TTY_TYPE_PTM ||
> +		    info->type == TTY_TYPE_PTS) {
> +			info->reg_d = pty_alloc_fake_reg_d(info, true);
> +			if (!info->reg_d) {
> +				pr_err("Can't generate new reg_d descriptor for id %#x\n",
> +				       info->tfe->id);
> +				return -1;
> +			}
> +		} else {
> +			pr_err("No reg_d descriptor for id %#x\n", info->tfe->id);
>  			return -1;
>  		}
>  	}
> @@ -1195,8 +1251,10 @@ static int collect_one_tty(void *obj, ProtobufCMessage *msg)
>  	 * can't be used. Most likely they appear if a user has
>  	 * dumped program when it was closing a peer.
>  	 */
> -	if (info->tie->termios)
> -		tty_test_and_set(info->tfe->tty_info_id, tty_active_pairs);
> +	if (info->type == TTY_TYPE_PTM || info->type == TTY_TYPE_PTS) {
> +		if (info->tie->termios)
> +			tty_test_and_set(info->tfe->tty_info_id, tty_active_pairs);
> +	}
>  
>  	pr_info("Collected tty ID %#x\n", info->tfe->id);
>  
> @@ -1264,7 +1322,7 @@ int dump_verify_tty_sids(void)
>  	return ret;
>  }
>  
> -static int dump_pty_info(int lfd, u32 id, const struct fd_parms *p, int type, int index)
> +static int dump_tty_info(int lfd, u32 id, const struct fd_parms *p, int type, int index)
>  {
>  	TtyInfoEntry info		= TTY_INFO_ENTRY__INIT;
>  	TermiosEntry termios		= TERMIOS_ENTRY__INIT;
> @@ -1304,18 +1362,28 @@ static int dump_pty_info(int lfd, u32 id, const struct fd_parms *p, int type, in
>  	list_add_tail(&dinfo->list, &all_ttys);
>  
>  	info.id			= id;
> -	info.type		= TTY_TYPE__PTY;
>  	info.sid		= pti->sid;
>  	info.pgrp		= pti->pgrp;
>  	info.rdev		= p->stat.st_rdev;
> -	info.pty		= &pty;
> +
> +	switch (type) {
> +	case TTY_TYPE_PTM:
> +	case TTY_TYPE_PTS:
> +		info.type	= TTY_TYPE__PTY;
> +		info.pty	= &pty;
> +		pty.index	= index;
> +		break;
> +	case TTY_TYPE_CONSOLE:
> +		info.type	= TTY_TYPE__CONSOLE;
> +		break;
> +	default:
> +		BUG();
> +	}
>  
>  	info.locked		= pti->st_lock;
>  	info.exclusive		= pti->st_excl;
>  	info.packet_mode	= pti->st_pckt;
>  
> -	pty.index		= index;
> -
>  	/*
>  	 * Nothing we can do on hanging up terminal,
>  	 * just write out minimum information we can
> @@ -1331,7 +1399,8 @@ static int dump_pty_info(int lfd, u32 id, const struct fd_parms *p, int type, in
>  	 * not yet supported by our tool and better to
>  	 * inform a user about such situation.
>  	 */
> -	tty_test_and_set(id, tty_active_pairs);
> +	if (type == TTY_TYPE_PTM || type == TTY_TYPE_PTS)
> +		tty_test_and_set(id, tty_active_pairs);
>  
>  	info.termios		= &termios;
>  	info.termios_locked	= &termios_locked;
> @@ -1374,10 +1443,10 @@ out:
>  	return ret;
>  }
>  
> -static int dump_one_pty(int lfd, u32 id, const struct fd_parms *p)
> +static int dump_one_tty(int lfd, u32 id, const struct fd_parms *p)
>  {
>  	TtyFileEntry e = TTY_FILE_ENTRY__INIT;
> -	int ret = 0, type, index;
> +	int ret = 0, type, index = -1;
>  
>  	pr_info("Dumping tty %d with id %#x\n", lfd, id);
>  
> @@ -1385,9 +1454,19 @@ static int dump_one_pty(int lfd, u32 id, const struct fd_parms *p)
>  		return -1;
>  
>  	type = tty_type(major(p->stat.st_rdev), minor(p->stat.st_rdev));
> -	index = parse_pty_index(id, lfd, p, type);
> -	if (index < 0)
> -		return -1;
> +	switch (type) {
> +	case TTY_TYPE_PTM:
> +	case TTY_TYPE_PTS:
> +		index = parse_pty_index(id, lfd, p, type);
> +		if (index < 0)
> +			return -1;
> +		break;
> +	case TTY_TYPE_CONSOLE:
> +		index = CONSOLE_INDEX;
> +		break;
> +	default:
> +		BUG();
> +	}
>  
>  	e.id		= id;
>  	e.tty_info_id	= tty_gen_id(type, index);
> @@ -1415,7 +1494,7 @@ static int dump_one_pty(int lfd, u32 id, const struct fd_parms *p)
>  	 */
>  
>  	if (!tty_test_and_set(e.tty_info_id, tty_bitmap))
> -		ret = dump_pty_info(lfd, e.tty_info_id, p, type, index);
> +		ret = dump_tty_info(lfd, e.tty_info_id, p, type, index);
>  
>  	if (!ret)
>  		ret = pb_write_one(img_from_set(glob_imgset, CR_FD_TTY_FILES), &e, PB_TTY_FILE);
> @@ -1424,7 +1503,7 @@ static int dump_one_pty(int lfd, u32 id, const struct fd_parms *p)
>  
>  const struct fdtype_ops tty_dump_ops = {
>  	.type	= FD_TYPES__TTY,
> -	.dump	= dump_one_pty,
> +	.dump	= dump_one_tty,
>  };
>  
>  int tty_prep_fds(void)
> -- 
> 1.9.3
> 
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