/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
 */
/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */


#ifndef _SYS_PTMS_H
#define _SYS_PTMS_H

#ifdef  __cplusplus
extern "C" {
#endif

#ifdef _KERNEL

/*
 * Structures and definitions supporting the pseudo-terminal drivers. This
 * structure is private and should not be used by any applications.
 */
struct pt_ttys {
        queue_t *ptm_rdq;       /* manager's read queue pointer */
        queue_t *pts_rdq;       /* subsidiary's read queue pointer */
        mblk_t  *pt_nullmsg;    /* 0-bytes message block for pts close */
        pid_t    pt_pid;        /* process id (for debugging) */
        minor_t  pt_minor;      /* Minor number of this pty */
        int      pt_refcnt;     /* reference count for ptm_rdq/pts_rdq uses */
        ushort_t pt_state;      /* state of manager/subsidiary pair */
        kcondvar_t pt_cv;       /* condition variable for exclusive access */
        kmutex_t pt_lock;       /* Per-element lock */
        zoneid_t pt_zoneid;     /* Zone membership for this pty */
        uid_t    pt_ruid;       /* Real owner of pty */
        gid_t    pt_rgid;       /* Real group owner of pty */
};

/*
 * pt_state values
 */
#define PTLOCK          0x01    /* manager/subsidiary pair is locked */
#define PTMOPEN         0x02    /* manager side is open */
#define PTSOPEN         0x04    /* subsidiary side is open */
#define PTSTTY          0x08    /* subsidiary side is tty */

/*
 * Multi-threading primitives.
 * Values of pt_refcnt: -1 if a writer is accessing the struct
 *                      0  if no one is reading or writing
 *                      > 0 equals to the number of readers accessing the struct
 */
#define PT_ENTER_READ(p) {                      \
        mutex_enter(&(p)->pt_lock);             \
        while ((p)->pt_refcnt < 0)              \
                cv_wait(&((p)->pt_cv), &(p)->pt_lock);  \
        (p)->pt_refcnt++;                       \
        mutex_exit(&(p)->pt_lock);              \
}

#define PT_ENTER_WRITE(p) {                     \
        mutex_enter(&(p)->pt_lock);             \
        while ((p)->pt_refcnt != 0)             \
                cv_wait(&((p)->pt_cv), &(p)->pt_lock);  \
        (p)->pt_refcnt = -1;                    \
        mutex_exit(&(p)->pt_lock);              \
}

#define PT_EXIT_READ(p) {                       \
        mutex_enter(&(p)->pt_lock);             \
        ASSERT((p)->pt_refcnt > 0);             \
        if ((--((p)->pt_refcnt)) == 0)          \
                cv_broadcast(&(p)->pt_cv);      \
        mutex_exit(&(p)->pt_lock);              \
}

#define PT_EXIT_WRITE(p) {                      \
        mutex_enter(&(p)->pt_lock);             \
        ASSERT((p)->pt_refcnt == -1);           \
        (p)->pt_refcnt = 0;                     \
        cv_broadcast(&(p)->pt_cv);              \
        mutex_exit(&(p)->pt_lock);              \
}

/*
 * ptms_lock and pt_cnt are defined in ptms_conf.c
 */
extern kmutex_t         ptms_lock;
extern dev_info_t       *pts_dip;       /* private copy of devinfo ptr */

extern void ptms_init(void);
extern struct pt_ttys *pt_ttys_alloc(void);
extern void ptms_close(struct pt_ttys *, uint_t);
extern struct pt_ttys *ptms_minor2ptty(minor_t);
extern int ptms_attach_subsidiary(void);
extern int ptms_minor_valid(minor_t ptmin, uid_t *uid, gid_t *gid);
extern int ptms_minor_exists(minor_t ptmin);
extern void ptms_set_owner(minor_t ptmin, uid_t uid, gid_t gid);
extern major_t ptms_subsidiary_attached(void);

#ifdef DEBUG
extern void ptms_log(char *, uint_t);
extern void ptms_logp(char *, uintptr_t);
#define DDBG(a, b) ptms_log(a, b)
#define DDBGP(a, b) ptms_logp(a, b)
#else
#define DDBG(a, b)
#define DDBGP(a, b)
#endif

#endif /* _KERNEL */

typedef struct pt_own {
        uid_t   pto_ruid;
        gid_t   pto_rgid;
} pt_own_t;

/*
 * IOCTL COMMANDS
 *
 *      ISPTM
 *              Determines whether the file descriptor is that of an open
 *              manager device.  Return code of zero indicates that the file
 *              descriptor represents a manager device.
 *
 *      UNLKPT
 *              Unlocks the manager and subsidiary devices.  It returns 0 on
 *              success.  On failure, the errno is set to EINVAL indicating
 *              that the manager device is not open.
 *
 *      ZONEPT
 *              Sets the zoneid of the pair of manager and subsidiary devices.
 *              It returns 0 upon success.  Used to force a pty 'into' a zone
 *              upon zone entry.
 *
 *      PT_OWNER
 *              Sets uid and gid for subsidiary device.  It returns 0 on
 *              success.
 */
#define ISPTM           (('P'<<8)|1)  /* query for manager */
#define UNLKPT          (('P'<<8)|2)  /* unlock manager/subsidiary pair */
#define PTSSTTY         (('P'<<8)|3)  /* set tty flag */
#define ZONEPT          (('P'<<8)|4)  /* set zone of manager/subsidiary pair */
#define OWNERPT         (('P'<<8)|5)  /* set owner/group for subsidiary */

#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_PTMS_H */