2005-04-17 00:20:36 +02:00
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/* -*- linux-c -*- --------------------------------------------------------- *
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*
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* linux/fs/devpts/inode.c
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*
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* Copyright 1998-2004 H. Peter Anvin -- All Rights Reserved
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*
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* This file is part of the Linux kernel and is made available under
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* the terms of the GNU General Public License, version 2, or at your
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* option, any later version, incorporated herein by reference.
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*
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* ------------------------------------------------------------------------- */
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/tty.h>
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2008-04-30 09:54:21 +02:00
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#include <linux/mutex.h>
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#include <linux/idr.h>
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2005-04-17 00:20:36 +02:00
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#include <linux/devpts_fs.h>
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2006-03-23 12:00:59 +01:00
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#include <linux/parser.h>
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2007-05-08 09:24:18 +02:00
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#include <linux/fsnotify.h>
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2008-02-08 13:21:41 +01:00
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#include <linux/seq_file.h>
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2005-04-17 00:20:36 +02:00
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#define DEVPTS_SUPER_MAGIC 0x1cd1
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2008-02-08 13:21:41 +01:00
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#define DEVPTS_DEFAULT_MODE 0600
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2009-01-02 14:42:02 +01:00
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/*
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* ptmx is a new node in /dev/pts and will be unused in legacy (single-
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* instance) mode. To prevent surprises in user space, set permissions of
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* ptmx to 0. Use 'chmod' or remount with '-o ptmxmode' to set meaningful
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* permissions.
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*/
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#define DEVPTS_DEFAULT_PTMX_MODE 0000
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2008-10-13 11:43:08 +02:00
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#define PTMX_MINOR 2
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2008-02-08 13:21:41 +01:00
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2008-04-30 09:54:21 +02:00
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extern int pty_limit; /* Config limit on Unix98 ptys */
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static DEFINE_MUTEX(allocated_ptys_lock);
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2005-04-17 00:20:36 +02:00
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static struct vfsmount *devpts_mnt;
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2009-01-02 14:41:33 +01:00
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struct pts_mount_opts {
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2005-04-17 00:20:36 +02:00
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int setuid;
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int setgid;
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uid_t uid;
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gid_t gid;
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umode_t mode;
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2009-01-02 14:42:02 +01:00
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umode_t ptmxmode;
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Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
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int newinstance;
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2009-01-02 14:41:33 +01:00
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};
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2005-04-17 00:20:36 +02:00
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2006-03-23 12:00:59 +01:00
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enum {
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Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
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Opt_uid, Opt_gid, Opt_mode, Opt_ptmxmode, Opt_newinstance,
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2006-03-23 12:00:59 +01:00
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Opt_err
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};
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2008-10-13 11:46:57 +02:00
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static const match_table_t tokens = {
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2006-03-23 12:00:59 +01:00
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{Opt_uid, "uid=%u"},
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{Opt_gid, "gid=%u"},
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{Opt_mode, "mode=%o"},
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2009-01-02 14:42:02 +01:00
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#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
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{Opt_ptmxmode, "ptmxmode=%o"},
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Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
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{Opt_newinstance, "newinstance"},
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2009-01-02 14:42:02 +01:00
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#endif
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2006-03-23 12:00:59 +01:00
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{Opt_err, NULL}
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};
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2009-01-02 14:41:21 +01:00
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struct pts_fs_info {
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struct ida allocated_ptys;
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2009-01-02 14:41:33 +01:00
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struct pts_mount_opts mount_opts;
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2009-01-02 14:42:02 +01:00
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struct dentry *ptmx_dentry;
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2009-01-02 14:41:21 +01:00
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};
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static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb)
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{
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return sb->s_fs_info;
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}
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2009-01-02 14:41:11 +01:00
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static inline struct super_block *pts_sb_from_inode(struct inode *inode)
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{
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Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
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#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
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2009-01-02 14:41:11 +01:00
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if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC)
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return inode->i_sb;
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Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
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#endif
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2009-01-02 14:41:11 +01:00
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return devpts_mnt->mnt_sb;
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}
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Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
|
|
|
#define PARSE_MOUNT 0
|
|
|
|
#define PARSE_REMOUNT 1
|
|
|
|
|
|
|
|
static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)
|
2005-04-17 00:20:36 +02:00
|
|
|
{
|
2006-03-23 12:00:59 +01:00
|
|
|
char *p;
|
|
|
|
|
2009-01-02 14:41:33 +01:00
|
|
|
opts->setuid = 0;
|
|
|
|
opts->setgid = 0;
|
|
|
|
opts->uid = 0;
|
|
|
|
opts->gid = 0;
|
|
|
|
opts->mode = DEVPTS_DEFAULT_MODE;
|
2009-01-02 14:42:02 +01:00
|
|
|
opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
|
2006-03-23 12:00:59 +01:00
|
|
|
|
Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
|
|
|
/* newinstance makes sense only on initial mount */
|
|
|
|
if (op == PARSE_MOUNT)
|
|
|
|
opts->newinstance = 0;
|
|
|
|
|
2006-03-23 12:00:59 +01:00
|
|
|
while ((p = strsep(&data, ",")) != NULL) {
|
|
|
|
substring_t args[MAX_OPT_ARGS];
|
|
|
|
int token;
|
|
|
|
int option;
|
|
|
|
|
|
|
|
if (!*p)
|
2005-04-17 00:20:36 +02:00
|
|
|
continue;
|
2006-03-23 12:00:59 +01:00
|
|
|
|
|
|
|
token = match_token(p, tokens, args);
|
|
|
|
switch (token) {
|
|
|
|
case Opt_uid:
|
|
|
|
if (match_int(&args[0], &option))
|
|
|
|
return -EINVAL;
|
2009-01-02 14:41:33 +01:00
|
|
|
opts->uid = option;
|
|
|
|
opts->setuid = 1;
|
2006-03-23 12:00:59 +01:00
|
|
|
break;
|
|
|
|
case Opt_gid:
|
|
|
|
if (match_int(&args[0], &option))
|
|
|
|
return -EINVAL;
|
2009-01-02 14:41:33 +01:00
|
|
|
opts->gid = option;
|
|
|
|
opts->setgid = 1;
|
2006-03-23 12:00:59 +01:00
|
|
|
break;
|
|
|
|
case Opt_mode:
|
|
|
|
if (match_octal(&args[0], &option))
|
|
|
|
return -EINVAL;
|
2009-01-02 14:41:33 +01:00
|
|
|
opts->mode = option & S_IALLUGO;
|
2006-03-23 12:00:59 +01:00
|
|
|
break;
|
2009-01-02 14:42:02 +01:00
|
|
|
#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
|
|
|
|
case Opt_ptmxmode:
|
|
|
|
if (match_octal(&args[0], &option))
|
|
|
|
return -EINVAL;
|
|
|
|
opts->ptmxmode = option & S_IALLUGO;
|
|
|
|
break;
|
Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
|
|
|
case Opt_newinstance:
|
|
|
|
/* newinstance makes sense only on initial mount */
|
|
|
|
if (op == PARSE_MOUNT)
|
|
|
|
opts->newinstance = 1;
|
|
|
|
break;
|
2009-01-02 14:42:02 +01:00
|
|
|
#endif
|
2006-03-23 12:00:59 +01:00
|
|
|
default:
|
|
|
|
printk(KERN_ERR "devpts: called with bogus options\n");
|
2005-04-17 00:20:36 +02:00
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-01-02 14:42:02 +01:00
|
|
|
#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
|
|
|
|
static int mknod_ptmx(struct super_block *sb)
|
|
|
|
{
|
|
|
|
int mode;
|
|
|
|
int rc = -ENOMEM;
|
|
|
|
struct dentry *dentry;
|
|
|
|
struct inode *inode;
|
|
|
|
struct dentry *root = sb->s_root;
|
|
|
|
struct pts_fs_info *fsi = DEVPTS_SB(sb);
|
|
|
|
struct pts_mount_opts *opts = &fsi->mount_opts;
|
|
|
|
|
|
|
|
mutex_lock(&root->d_inode->i_mutex);
|
|
|
|
|
|
|
|
/* If we have already created ptmx node, return */
|
|
|
|
if (fsi->ptmx_dentry) {
|
|
|
|
rc = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
dentry = d_alloc_name(root, "ptmx");
|
|
|
|
if (!dentry) {
|
|
|
|
printk(KERN_NOTICE "Unable to alloc dentry for ptmx node\n");
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Create a new 'ptmx' node in this mount of devpts.
|
|
|
|
*/
|
|
|
|
inode = new_inode(sb);
|
|
|
|
if (!inode) {
|
|
|
|
printk(KERN_ERR "Unable to alloc inode for ptmx node\n");
|
|
|
|
dput(dentry);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
inode->i_ino = 2;
|
|
|
|
inode->i_uid = inode->i_gid = 0;
|
|
|
|
inode->i_blocks = 0;
|
|
|
|
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
|
|
|
|
|
|
|
|
mode = S_IFCHR|opts->ptmxmode;
|
|
|
|
init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2));
|
|
|
|
|
|
|
|
d_add(dentry, inode);
|
|
|
|
|
|
|
|
fsi->ptmx_dentry = dentry;
|
|
|
|
rc = 0;
|
|
|
|
|
|
|
|
printk(KERN_DEBUG "Created ptmx node in devpts ino %lu\n",
|
|
|
|
inode->i_ino);
|
|
|
|
out:
|
|
|
|
mutex_unlock(&root->d_inode->i_mutex);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void update_ptmx_mode(struct pts_fs_info *fsi)
|
|
|
|
{
|
|
|
|
struct inode *inode;
|
|
|
|
if (fsi->ptmx_dentry) {
|
|
|
|
inode = fsi->ptmx_dentry->d_inode;
|
|
|
|
inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#else
|
|
|
|
static inline void update_ptmx_mode(struct pts_fs_info *fsi)
|
|
|
|
{
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
2009-01-02 14:41:47 +01:00
|
|
|
static int devpts_remount(struct super_block *sb, int *flags, char *data)
|
|
|
|
{
|
2009-01-02 14:42:02 +01:00
|
|
|
int err;
|
2009-01-02 14:41:47 +01:00
|
|
|
struct pts_fs_info *fsi = DEVPTS_SB(sb);
|
|
|
|
struct pts_mount_opts *opts = &fsi->mount_opts;
|
|
|
|
|
Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
|
|
|
err = parse_mount_options(data, PARSE_REMOUNT, opts);
|
2009-01-02 14:42:02 +01:00
|
|
|
|
|
|
|
/*
|
|
|
|
* parse_mount_options() restores options to default values
|
|
|
|
* before parsing and may have changed ptmxmode. So, update the
|
|
|
|
* mode in the inode too. Bogus options don't fail the remount,
|
|
|
|
* so do this even on error return.
|
|
|
|
*/
|
|
|
|
update_ptmx_mode(fsi);
|
|
|
|
|
|
|
|
return err;
|
2009-01-02 14:41:47 +01:00
|
|
|
}
|
|
|
|
|
2008-02-08 13:21:41 +01:00
|
|
|
static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs)
|
|
|
|
{
|
2009-01-02 14:41:33 +01:00
|
|
|
struct pts_fs_info *fsi = DEVPTS_SB(vfs->mnt_sb);
|
|
|
|
struct pts_mount_opts *opts = &fsi->mount_opts;
|
|
|
|
|
|
|
|
if (opts->setuid)
|
|
|
|
seq_printf(seq, ",uid=%u", opts->uid);
|
|
|
|
if (opts->setgid)
|
|
|
|
seq_printf(seq, ",gid=%u", opts->gid);
|
|
|
|
seq_printf(seq, ",mode=%03o", opts->mode);
|
2009-01-02 14:42:02 +01:00
|
|
|
#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
|
|
|
|
seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode);
|
|
|
|
#endif
|
2008-02-08 13:21:41 +01:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2007-02-12 09:55:41 +01:00
|
|
|
static const struct super_operations devpts_sops = {
|
2005-04-17 00:20:36 +02:00
|
|
|
.statfs = simple_statfs,
|
|
|
|
.remount_fs = devpts_remount,
|
2008-02-08 13:21:41 +01:00
|
|
|
.show_options = devpts_show_options,
|
2005-04-17 00:20:36 +02:00
|
|
|
};
|
|
|
|
|
2009-01-02 14:41:21 +01:00
|
|
|
static void *new_pts_fs_info(void)
|
|
|
|
{
|
|
|
|
struct pts_fs_info *fsi;
|
|
|
|
|
|
|
|
fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL);
|
|
|
|
if (!fsi)
|
|
|
|
return NULL;
|
|
|
|
|
|
|
|
ida_init(&fsi->allocated_ptys);
|
2009-01-02 14:41:33 +01:00
|
|
|
fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE;
|
2009-01-02 14:42:02 +01:00
|
|
|
fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
|
2009-01-02 14:41:21 +01:00
|
|
|
|
|
|
|
return fsi;
|
|
|
|
}
|
|
|
|
|
2005-04-17 00:20:36 +02:00
|
|
|
static int
|
|
|
|
devpts_fill_super(struct super_block *s, void *data, int silent)
|
|
|
|
{
|
2009-01-02 14:42:02 +01:00
|
|
|
struct inode *inode;
|
2005-04-17 00:20:36 +02:00
|
|
|
|
|
|
|
s->s_blocksize = 1024;
|
|
|
|
s->s_blocksize_bits = 10;
|
|
|
|
s->s_magic = DEVPTS_SUPER_MAGIC;
|
|
|
|
s->s_op = &devpts_sops;
|
|
|
|
s->s_time_gran = 1;
|
|
|
|
|
2009-01-02 14:41:21 +01:00
|
|
|
s->s_fs_info = new_pts_fs_info();
|
|
|
|
if (!s->s_fs_info)
|
|
|
|
goto fail;
|
|
|
|
|
2005-04-17 00:20:36 +02:00
|
|
|
inode = new_inode(s);
|
|
|
|
if (!inode)
|
2009-01-02 14:41:21 +01:00
|
|
|
goto free_fsi;
|
2005-04-17 00:20:36 +02:00
|
|
|
inode->i_ino = 1;
|
|
|
|
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
|
|
|
|
inode->i_blocks = 0;
|
|
|
|
inode->i_uid = inode->i_gid = 0;
|
|
|
|
inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
|
|
|
|
inode->i_op = &simple_dir_inode_operations;
|
|
|
|
inode->i_fop = &simple_dir_operations;
|
|
|
|
inode->i_nlink = 2;
|
|
|
|
|
2009-01-02 14:41:11 +01:00
|
|
|
s->s_root = d_alloc_root(inode);
|
2005-04-17 00:20:36 +02:00
|
|
|
if (s->s_root)
|
|
|
|
return 0;
|
2009-01-02 14:42:02 +01:00
|
|
|
|
2005-04-17 00:20:36 +02:00
|
|
|
printk("devpts: get root dentry failed\n");
|
|
|
|
iput(inode);
|
2009-01-02 14:41:21 +01:00
|
|
|
|
|
|
|
free_fsi:
|
|
|
|
kfree(s->s_fs_info);
|
2005-04-17 00:20:36 +02:00
|
|
|
fail:
|
|
|
|
return -ENOMEM;
|
|
|
|
}
|
|
|
|
|
2009-01-02 14:42:19 +01:00
|
|
|
static int compare_init_pts_sb(struct super_block *s, void *p)
|
|
|
|
{
|
|
|
|
if (devpts_mnt)
|
|
|
|
return devpts_mnt->mnt_sb == s;
|
Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
|
|
|
|
/*
|
|
|
|
* Safely parse the mount options in @data and update @opts.
|
|
|
|
*
|
|
|
|
* devpts ends up parsing options two times during mount, due to the
|
|
|
|
* two modes of operation it supports. The first parse occurs in
|
|
|
|
* devpts_get_sb() when determining the mode (single-instance or
|
|
|
|
* multi-instance mode). The second parse happens in devpts_remount()
|
|
|
|
* or new_pts_mount() depending on the mode.
|
|
|
|
*
|
|
|
|
* Parsing of options modifies the @data making subsequent parsing
|
|
|
|
* incorrect. So make a local copy of @data and parse it.
|
|
|
|
*
|
|
|
|
* Return: 0 On success, -errno on error
|
|
|
|
*/
|
|
|
|
static int safe_parse_mount_options(void *data, struct pts_mount_opts *opts)
|
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
void *datacp;
|
|
|
|
|
|
|
|
if (!data)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
/* Use kstrdup() ? */
|
|
|
|
datacp = kmalloc(PAGE_SIZE, GFP_KERNEL);
|
|
|
|
if (!datacp)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
memcpy(datacp, data, PAGE_SIZE);
|
|
|
|
rc = parse_mount_options((char *)datacp, PARSE_MOUNT, opts);
|
|
|
|
kfree(datacp);
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Mount a new (private) instance of devpts. PTYs created in this
|
|
|
|
* instance are independent of the PTYs in other devpts instances.
|
|
|
|
*/
|
|
|
|
static int new_pts_mount(struct file_system_type *fs_type, int flags,
|
|
|
|
void *data, struct vfsmount *mnt)
|
|
|
|
{
|
|
|
|
int err;
|
|
|
|
struct pts_fs_info *fsi;
|
|
|
|
struct pts_mount_opts *opts;
|
|
|
|
|
|
|
|
printk(KERN_NOTICE "devpts: newinstance mount\n");
|
|
|
|
|
|
|
|
err = get_sb_nodev(fs_type, flags, data, devpts_fill_super, mnt);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
fsi = DEVPTS_SB(mnt->mnt_sb);
|
|
|
|
opts = &fsi->mount_opts;
|
|
|
|
|
|
|
|
err = parse_mount_options(data, PARSE_MOUNT, opts);
|
|
|
|
if (err)
|
|
|
|
goto fail;
|
|
|
|
|
|
|
|
err = mknod_ptmx(mnt->mnt_sb);
|
|
|
|
if (err)
|
|
|
|
goto fail;
|
2009-01-02 14:42:19 +01:00
|
|
|
|
|
|
|
return 0;
|
Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
|
|
|
|
|
|
|
fail:
|
|
|
|
dput(mnt->mnt_sb->s_root);
|
|
|
|
deactivate_super(mnt->mnt_sb);
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Check if 'newinstance' mount option was specified in @data.
|
|
|
|
*
|
|
|
|
* Return: -errno on error (eg: invalid mount options specified)
|
|
|
|
* : 1 if 'newinstance' mount option was specified
|
|
|
|
* : 0 if 'newinstance' mount option was NOT specified
|
|
|
|
*/
|
|
|
|
static int is_new_instance_mount(void *data)
|
|
|
|
{
|
|
|
|
int rc;
|
|
|
|
struct pts_mount_opts opts;
|
|
|
|
|
|
|
|
if (!data)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
rc = safe_parse_mount_options(data, &opts);
|
|
|
|
if (!rc)
|
|
|
|
rc = opts.newinstance;
|
|
|
|
|
|
|
|
return rc;
|
2009-01-02 14:42:19 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* get_init_pts_sb()
|
|
|
|
*
|
|
|
|
* This interface is needed to support multiple namespace semantics in
|
|
|
|
* devpts while preserving backward compatibility of the current 'single-
|
|
|
|
* namespace' semantics. i.e all mounts of devpts without the 'newinstance'
|
|
|
|
* mount option should bind to the initial kernel mount, like
|
|
|
|
* get_sb_single().
|
|
|
|
*
|
|
|
|
* Mounts with 'newinstance' option create a new private namespace.
|
|
|
|
*
|
|
|
|
* But for single-mount semantics, devpts cannot use get_sb_single(),
|
|
|
|
* because get_sb_single()/sget() find and use the super-block from
|
|
|
|
* the most recent mount of devpts. But that recent mount may be a
|
|
|
|
* 'newinstance' mount and get_sb_single() would pick the newinstance
|
|
|
|
* super-block instead of the initial super-block.
|
|
|
|
*
|
|
|
|
* This interface is identical to get_sb_single() except that it
|
|
|
|
* consistently selects the 'single-namespace' superblock even in the
|
|
|
|
* presence of the private namespace (i.e 'newinstance') super-blocks.
|
|
|
|
*/
|
|
|
|
static int get_init_pts_sb(struct file_system_type *fs_type, int flags,
|
|
|
|
void *data, struct vfsmount *mnt)
|
|
|
|
{
|
|
|
|
struct super_block *s;
|
|
|
|
int error;
|
|
|
|
|
|
|
|
s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL);
|
|
|
|
if (IS_ERR(s))
|
|
|
|
return PTR_ERR(s);
|
|
|
|
|
|
|
|
if (!s->s_root) {
|
|
|
|
s->s_flags = flags;
|
|
|
|
error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
|
|
|
|
if (error) {
|
|
|
|
up_write(&s->s_umount);
|
|
|
|
deactivate_super(s);
|
|
|
|
return error;
|
|
|
|
}
|
|
|
|
s->s_flags |= MS_ACTIVE;
|
|
|
|
}
|
|
|
|
do_remount_sb(s, flags, data, 0);
|
|
|
|
return simple_set_mnt(mnt, s);
|
|
|
|
}
|
|
|
|
|
Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
|
|
|
/*
|
|
|
|
* Mount or remount the initial kernel mount of devpts. This type of
|
|
|
|
* mount maintains the legacy, single-instance semantics, while the
|
|
|
|
* kernel still allows multiple-instances.
|
|
|
|
*/
|
|
|
|
static int init_pts_mount(struct file_system_type *fs_type, int flags,
|
|
|
|
void *data, struct vfsmount *mnt)
|
|
|
|
{
|
|
|
|
int err;
|
|
|
|
|
|
|
|
err = get_init_pts_sb(fs_type, flags, data, mnt);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
err = mknod_ptmx(mnt->mnt_sb);
|
|
|
|
if (err) {
|
|
|
|
dput(mnt->mnt_sb->s_root);
|
|
|
|
deactivate_super(mnt->mnt_sb);
|
|
|
|
}
|
|
|
|
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
[PATCH] VFS: Permit filesystem to override root dentry on mount
Extend the get_sb() filesystem operation to take an extra argument that
permits the VFS to pass in the target vfsmount that defines the mountpoint.
The filesystem is then required to manually set the superblock and root dentry
pointers. For most filesystems, this should be done with simple_set_mnt()
which will set the superblock pointer and then set the root dentry to the
superblock's s_root (as per the old default behaviour).
The get_sb() op now returns an integer as there's now no need to return the
superblock pointer.
This patch permits a superblock to be implicitly shared amongst several mount
points, such as can be done with NFS to avoid potential inode aliasing. In
such a case, simple_set_mnt() would not be called, and instead the mnt_root
and mnt_sb would be set directly.
The patch also makes the following changes:
(*) the get_sb_*() convenience functions in the core kernel now take a vfsmount
pointer argument and return an integer, so most filesystems have to change
very little.
(*) If one of the convenience function is not used, then get_sb() should
normally call simple_set_mnt() to instantiate the vfsmount. This will
always return 0, and so can be tail-called from get_sb().
(*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the
dcache upon superblock destruction rather than shrink_dcache_anon().
This is required because the superblock may now have multiple trees that
aren't actually bound to s_root, but that still need to be cleaned up. The
currently called functions assume that the whole tree is rooted at s_root,
and that anonymous dentries are not the roots of trees which results in
dentries being left unculled.
However, with the way NFS superblock sharing are currently set to be
implemented, these assumptions are violated: the root of the filesystem is
simply a dummy dentry and inode (the real inode for '/' may well be
inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries
with child trees.
[*] Anonymous until discovered from another tree.
(*) The documentation has been adjusted, including the additional bit of
changing ext2_* into foo_* in the documentation.
[akpm@osdl.org: convert ipath_fs, do other stuff]
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 11:02:57 +02:00
|
|
|
static int devpts_get_sb(struct file_system_type *fs_type,
|
|
|
|
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
|
2005-04-17 00:20:36 +02:00
|
|
|
{
|
Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
|
|
|
int new;
|
|
|
|
|
|
|
|
new = is_new_instance_mount(data);
|
|
|
|
if (new < 0)
|
|
|
|
return new;
|
|
|
|
|
|
|
|
if (new)
|
|
|
|
return new_pts_mount(fs_type, flags, data, mnt);
|
|
|
|
|
|
|
|
return init_pts_mount(fs_type, flags, data, mnt);
|
2005-04-17 00:20:36 +02:00
|
|
|
}
|
Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
|
|
|
#else
|
|
|
|
/*
|
|
|
|
* This supports only the legacy single-instance semantics (no
|
|
|
|
* multiple-instance semantics)
|
|
|
|
*/
|
|
|
|
static int devpts_get_sb(struct file_system_type *fs_type, int flags,
|
|
|
|
const char *dev_name, void *data, struct vfsmount *mnt)
|
|
|
|
{
|
|
|
|
return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt);
|
|
|
|
}
|
|
|
|
#endif
|
2005-04-17 00:20:36 +02:00
|
|
|
|
2009-01-02 14:41:21 +01:00
|
|
|
static void devpts_kill_sb(struct super_block *sb)
|
|
|
|
{
|
|
|
|
struct pts_fs_info *fsi = DEVPTS_SB(sb);
|
|
|
|
|
|
|
|
kfree(fsi);
|
2009-01-02 14:42:02 +01:00
|
|
|
kill_litter_super(sb);
|
2009-01-02 14:41:21 +01:00
|
|
|
}
|
|
|
|
|
2005-04-17 00:20:36 +02:00
|
|
|
static struct file_system_type devpts_fs_type = {
|
|
|
|
.owner = THIS_MODULE,
|
|
|
|
.name = "devpts",
|
|
|
|
.get_sb = devpts_get_sb,
|
2009-01-02 14:41:21 +01:00
|
|
|
.kill_sb = devpts_kill_sb,
|
2005-04-17 00:20:36 +02:00
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* The normal naming convention is simply /dev/pts/<number>; this conforms
|
|
|
|
* to the System V naming convention
|
|
|
|
*/
|
|
|
|
|
2008-10-13 11:42:59 +02:00
|
|
|
int devpts_new_index(struct inode *ptmx_inode)
|
2008-04-30 09:54:21 +02:00
|
|
|
{
|
2009-01-02 14:41:21 +01:00
|
|
|
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
|
|
|
|
struct pts_fs_info *fsi = DEVPTS_SB(sb);
|
2008-04-30 09:54:21 +02:00
|
|
|
int index;
|
2008-07-26 09:42:16 +02:00
|
|
|
int ida_ret;
|
2008-04-30 09:54:21 +02:00
|
|
|
|
|
|
|
retry:
|
2009-01-02 14:41:21 +01:00
|
|
|
if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL)) {
|
2008-04-30 09:54:21 +02:00
|
|
|
return -ENOMEM;
|
|
|
|
}
|
|
|
|
|
|
|
|
mutex_lock(&allocated_ptys_lock);
|
2009-01-02 14:41:21 +01:00
|
|
|
ida_ret = ida_get_new(&fsi->allocated_ptys, &index);
|
2008-07-26 09:42:16 +02:00
|
|
|
if (ida_ret < 0) {
|
2008-04-30 09:54:21 +02:00
|
|
|
mutex_unlock(&allocated_ptys_lock);
|
2008-07-26 09:42:16 +02:00
|
|
|
if (ida_ret == -EAGAIN)
|
2008-04-30 09:54:21 +02:00
|
|
|
goto retry;
|
|
|
|
return -EIO;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (index >= pty_limit) {
|
2009-01-02 14:41:21 +01:00
|
|
|
ida_remove(&fsi->allocated_ptys, index);
|
2008-04-30 09:54:21 +02:00
|
|
|
mutex_unlock(&allocated_ptys_lock);
|
|
|
|
return -EIO;
|
|
|
|
}
|
|
|
|
mutex_unlock(&allocated_ptys_lock);
|
|
|
|
return index;
|
|
|
|
}
|
|
|
|
|
2008-10-13 11:42:59 +02:00
|
|
|
void devpts_kill_index(struct inode *ptmx_inode, int idx)
|
2008-04-30 09:54:21 +02:00
|
|
|
{
|
2009-01-02 14:41:21 +01:00
|
|
|
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
|
|
|
|
struct pts_fs_info *fsi = DEVPTS_SB(sb);
|
|
|
|
|
2008-04-30 09:54:21 +02:00
|
|
|
mutex_lock(&allocated_ptys_lock);
|
2009-01-02 14:41:21 +01:00
|
|
|
ida_remove(&fsi->allocated_ptys, idx);
|
2008-04-30 09:54:21 +02:00
|
|
|
mutex_unlock(&allocated_ptys_lock);
|
|
|
|
}
|
|
|
|
|
2008-10-13 11:42:59 +02:00
|
|
|
int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
|
2005-04-17 00:20:36 +02:00
|
|
|
{
|
2008-04-30 09:54:21 +02:00
|
|
|
int number = tty->index; /* tty layer puts index from devpts_new_index() in here */
|
2005-04-17 00:20:36 +02:00
|
|
|
struct tty_driver *driver = tty->driver;
|
|
|
|
dev_t device = MKDEV(driver->major, driver->minor_start+number);
|
|
|
|
struct dentry *dentry;
|
2009-01-02 14:41:11 +01:00
|
|
|
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
|
|
|
|
struct inode *inode = new_inode(sb);
|
|
|
|
struct dentry *root = sb->s_root;
|
2009-01-02 14:41:33 +01:00
|
|
|
struct pts_fs_info *fsi = DEVPTS_SB(sb);
|
|
|
|
struct pts_mount_opts *opts = &fsi->mount_opts;
|
2008-10-13 11:43:18 +02:00
|
|
|
char s[12];
|
2005-04-17 00:20:36 +02:00
|
|
|
|
|
|
|
/* We're supposed to be given the slave end of a pty */
|
|
|
|
BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY);
|
|
|
|
BUG_ON(driver->subtype != PTY_TYPE_SLAVE);
|
|
|
|
|
|
|
|
if (!inode)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
inode->i_ino = number+2;
|
2008-11-14 00:38:49 +01:00
|
|
|
inode->i_uid = config.setuid ? config.uid : current_fsuid();
|
|
|
|
inode->i_gid = config.setgid ? config.gid : current_fsgid();
|
2005-04-17 00:20:36 +02:00
|
|
|
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
|
2009-01-02 14:41:33 +01:00
|
|
|
init_special_inode(inode, S_IFCHR|opts->mode, device);
|
2006-09-27 10:50:46 +02:00
|
|
|
inode->i_private = tty;
|
2008-10-13 11:43:27 +02:00
|
|
|
tty->driver_data = inode;
|
2005-04-17 00:20:36 +02:00
|
|
|
|
2008-10-13 11:43:18 +02:00
|
|
|
sprintf(s, "%d", number);
|
|
|
|
|
2009-01-02 14:41:11 +01:00
|
|
|
mutex_lock(&root->d_inode->i_mutex);
|
2008-10-13 11:43:18 +02:00
|
|
|
|
2009-01-02 14:41:11 +01:00
|
|
|
dentry = d_alloc_name(root, s);
|
2008-10-13 11:43:18 +02:00
|
|
|
if (!IS_ERR(dentry)) {
|
|
|
|
d_add(dentry, inode);
|
2009-01-02 14:41:11 +01:00
|
|
|
fsnotify_create(root->d_inode, dentry);
|
2007-05-08 09:24:18 +02:00
|
|
|
}
|
2005-04-17 00:20:36 +02:00
|
|
|
|
2009-01-02 14:41:11 +01:00
|
|
|
mutex_unlock(&root->d_inode->i_mutex);
|
2005-04-17 00:20:36 +02:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2008-10-13 11:42:59 +02:00
|
|
|
struct tty_struct *devpts_get_tty(struct inode *pts_inode, int number)
|
2005-04-17 00:20:36 +02:00
|
|
|
{
|
2008-10-13 11:43:08 +02:00
|
|
|
BUG_ON(pts_inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR));
|
2005-04-17 00:20:36 +02:00
|
|
|
|
2008-10-13 11:43:08 +02:00
|
|
|
if (pts_inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC)
|
|
|
|
return (struct tty_struct *)pts_inode->i_private;
|
|
|
|
return NULL;
|
2005-04-17 00:20:36 +02:00
|
|
|
}
|
|
|
|
|
2008-10-13 11:42:59 +02:00
|
|
|
void devpts_pty_kill(struct tty_struct *tty)
|
2005-04-17 00:20:36 +02:00
|
|
|
{
|
2008-10-13 11:43:27 +02:00
|
|
|
struct inode *inode = tty->driver_data;
|
2009-01-02 14:41:11 +01:00
|
|
|
struct super_block *sb = pts_sb_from_inode(inode);
|
|
|
|
struct dentry *root = sb->s_root;
|
2008-10-13 11:43:27 +02:00
|
|
|
struct dentry *dentry;
|
2005-04-17 00:20:36 +02:00
|
|
|
|
2008-10-13 11:43:27 +02:00
|
|
|
BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR));
|
|
|
|
|
2009-01-02 14:41:11 +01:00
|
|
|
mutex_lock(&root->d_inode->i_mutex);
|
2008-10-13 11:43:27 +02:00
|
|
|
|
|
|
|
dentry = d_find_alias(inode);
|
Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
|
|
|
if (IS_ERR(dentry))
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
if (dentry) {
|
2008-10-13 11:43:27 +02:00
|
|
|
inode->i_nlink--;
|
|
|
|
d_delete(dentry);
|
Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
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dput(dentry); // d_alloc_name() in devpts_pty_new()
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2005-04-17 00:20:36 +02:00
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}
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2008-10-13 11:43:27 +02:00
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Enable multiple instances of devpts
To support containers, allow multiple instances of devpts filesystem, such
that indices of ptys allocated in one instance are independent of ptys
allocated in other instances of devpts.
But to preserve backward compatibility, enable this support for multiple
instances only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES is set to Y, and
- '-o newinstance' mount option is specified while mounting devpts
To use multi-instance mount, a container startup script could:
$ ns_exec -cm /bin/bash
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ mount -o bind /dev/pts/ptmx /dev/ptmx
$ /usr/sbin/sshd -p 1234
where 'ns_exec -cm /bin/bash' is calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
USER-SPACE-IMPACT:
- See Documentation/fs/devpts.txt (included in next patch) for user-
space impact in multi-instance and mixed-mode operation.
TODO:
- Update mount(8), pts(4) man pages. Highlight impact of not
redirecting /dev/ptmx to /dev/pts/ptmx after a multi-instance mount.
Changelog[v6]:
- [Dave Hansen] Use new get_init_pts_sb() interface
- [Serge Hallyn] Don't bother displaying 'newinstance' in show_options
- [Serge Hallyn] Use macros (PARSE_REMOUNT/PARSE_MOUNT) instead of 0/1.
- [Serge Hallyn] Check error return from get_sb_single() (now
get_init_pts_sb())
- devpts_pty_kill(): don't dput error dentries
Changelog[v5]:
- Move get_sb_ref() definition to earlier patch
- Move usage info to Documentation/filesystems/devpts.txt (next patch)
- Make ptmx node even in init_pts_ns, now that default mode is 0000
(defined in earlier patch, enabled here).
- Cache ptmx dentry and use to update mode during remount
(defined in earlier patch, enabled here).
- Bugfix: explicitly ignore newinstance on remount (if newinstance was
specified on remount of initial mount, it would be ignored but
/proc/mounts would imply that the option was set)
Changelog[v4]:
- Update patch description to address H. Peter Anvin's comments
- Consolidate multi-instance mode code under new config token,
CONFIG_DEVPTS_MULTIPLE_INSTANCE.
- Move usage-details from patch description to
Documentation/fs/devpts.txt
Changelog[v3]:
- Rename new mount option to 'newinstance'
- Create ptmx nodes only in 'newinstance' mounts
- Bugfix: parse_mount_options() modifies @data but since we need to
parse the @data twice (once in devpts_get_sb() and once during
do_remount_sb()), parse a local copy of @data in devpts_get_sb().
(restructured code in devpts_get_sb() to fix this)
Changelog[v2]:
- Support both single-mount and multiple-mount semantics and
provide '-onewmnt' option to select the semantics.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 14:42:27 +01:00
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dput(dentry); // d_find_alias above
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out:
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2009-01-02 14:41:11 +01:00
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mutex_unlock(&root->d_inode->i_mutex);
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2005-04-17 00:20:36 +02:00
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}
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static int __init init_devpts_fs(void)
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{
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int err = register_filesystem(&devpts_fs_type);
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if (!err) {
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devpts_mnt = kern_mount(&devpts_fs_type);
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if (IS_ERR(devpts_mnt))
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err = PTR_ERR(devpts_mnt);
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}
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return err;
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}
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static void __exit exit_devpts_fs(void)
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{
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unregister_filesystem(&devpts_fs_type);
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mntput(devpts_mnt);
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}
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module_init(init_devpts_fs)
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module_exit(exit_devpts_fs)
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MODULE_LICENSE("GPL");
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