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Commit a4834c10 authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by Greg Kroah-Hartman
Browse files

tty: move pty count limiting into devpts 



Let's move this stuff to the better place, where we can account pty right in
tty-indexes managing code.

Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 593a27c4

drivers/tty/pty.c

+0 −51
Original line number Diff line number Diff line
@@ -21,7 +21,6 @@ 
#include <linux/major.h>

#include <linux/mm.h>

#include <linux/init.h>

#include <linux/sysctl.h>

#include <linux/device.h>

#include <linux/uaccess.h>

#include <linux/bitops.h>
@@ -439,55 +438,9 @@ static inline void legacy_pty_init(void) { } 


/* Unix98 devices */

#ifdef CONFIG_UNIX98_PTYS

/*

 * sysctl support for setting limits on the number of Unix98 ptys allocated.

 * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.

 */

int pty_limit = NR_UNIX98_PTY_DEFAULT;

static int pty_limit_min;

static int pty_limit_max = NR_UNIX98_PTY_MAX;

static int pty_count;



static struct cdev ptmx_cdev;



static struct ctl_table pty_table[] = {

	{

		.procname	= "max",

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.data		= &pty_limit,

		.proc_handler	= proc_dointvec_minmax,

		.extra1		= &pty_limit_min,

		.extra2		= &pty_limit_max,

	}, {

		.procname	= "nr",

		.maxlen		= sizeof(int),

		.mode		= 0444,

		.data		= &pty_count,

		.proc_handler	= proc_dointvec,

	}, 

	{}

};



static struct ctl_table pty_kern_table[] = {

	{

		.procname	= "pty",

		.mode		= 0555,

		.child		= pty_table,

	},

	{}

};



static struct ctl_table pty_root_table[] = {

	{

		.procname	= "kernel",

		.mode		= 0555,

		.child		= pty_kern_table,

	},

	{}

};





static int pty_unix98_ioctl(struct tty_struct *tty,

			    unsigned int cmd, unsigned long arg)

{
@@ -587,7 +540,6 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) 
	 */

	tty_driver_kref_get(driver);

	tty->count++;

	pty_count++;

	return 0;

err_free_mem:

	deinitialize_tty_struct(o_tty);
@@ -601,7 +553,6 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) 


static void ptm_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)

{

	pty_count--;

}



static void pts_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
@@ -760,8 +711,6 @@ static void __init unix98_pty_init(void) 
	if (tty_register_driver(pts_driver))

		panic("Couldn't register Unix98 pts driver");



	register_sysctl_table(pty_root_table);



	/* Now create the /dev/ptmx special device */

	tty_default_fops(&ptmx_fops);

	ptmx_fops.open = ptmx_open;

fs/devpts/inode.c

+52 −1
Original line number Diff line number Diff line
@@ -36,7 +36,52 @@ 
#define DEVPTS_DEFAULT_PTMX_MODE 0000

#define PTMX_MINOR	2



extern int pty_limit;			/* Config limit on Unix98 ptys */

/*

 * sysctl support for setting limits on the number of Unix98 ptys allocated.

 * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.

 */

static int pty_limit = NR_UNIX98_PTY_DEFAULT;

static int pty_limit_min;

static int pty_limit_max = NR_UNIX98_PTY_MAX;

static int pty_count;



static struct ctl_table pty_table[] = {

	{

		.procname	= "max",

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.data		= &pty_limit,

		.proc_handler	= proc_dointvec_minmax,

		.extra1		= &pty_limit_min,

		.extra2		= &pty_limit_max,

	}, {

		.procname	= "nr",

		.maxlen		= sizeof(int),

		.mode		= 0444,

		.data		= &pty_count,

		.proc_handler	= proc_dointvec,

	},

	{}

};



static struct ctl_table pty_kern_table[] = {

	{

		.procname	= "pty",

		.mode		= 0555,

		.child		= pty_table,

	},

	{}

};



static struct ctl_table pty_root_table[] = {

	{

		.procname	= "kernel",

		.mode		= 0555,

		.child		= pty_kern_table,

	},

	{}

};



static DEFINE_MUTEX(allocated_ptys_lock);



static struct vfsmount *devpts_mnt;
@@ -451,6 +496,7 @@ int devpts_new_index(struct inode *ptmx_inode) 
		mutex_unlock(&allocated_ptys_lock);

		return -EIO;

	}

	pty_count++;

	mutex_unlock(&allocated_ptys_lock);

	return index;

}
@@ -462,6 +508,7 @@ void devpts_kill_index(struct inode *ptmx_inode, int idx) 


	mutex_lock(&allocated_ptys_lock);

	ida_remove(&fsi->allocated_ptys, idx);

	pty_count--;

	mutex_unlock(&allocated_ptys_lock);

}
@@ -558,11 +605,15 @@ void devpts_pty_kill(struct tty_struct *tty) 
static int __init init_devpts_fs(void)

{

	int err = register_filesystem(&devpts_fs_type);

	struct ctl_table_header *table;



	if (!err) {

		table = register_sysctl_table(pty_root_table);

		devpts_mnt = kern_mount(&devpts_fs_type);

		if (IS_ERR(devpts_mnt)) {

			err = PTR_ERR(devpts_mnt);

			unregister_filesystem(&devpts_fs_type);

			unregister_sysctl_table(table);

		}

	}

	return err;