LCOM1920-T02G10

/*        $NetBSD: filedesc.h,v 1.63 2012/02/11 23:16:18 martin Exp $        */

/*-

 * Copyright (c) 2008 The NetBSD Foundation, Inc.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS

 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED

 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS

 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 */

/*

 * Copyright (c) 1990, 1993

 *        The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 *

 *        @(#)filedesc.h        8.1 (Berkeley) 6/2/93

 */

#ifndef _SYS_FILEDESC_H_

#define        _SYS_FILEDESC_H_

#include <sys/param.h>

#include <sys/queue.h>

#include <sys/mutex.h>

#include <sys/rwlock.h>

#include <sys/condvar.h>

/*

 * This structure is used for the management of descriptors.  It may be

 * shared by multiple processes.

 *

 * A process is initially started out with NDFILE descriptors stored within

 * this structure, selected to be enough for typical applications based on

 * the historical limit of 20 open files (and the usage of descriptors by

 * shells).  If these descriptors are exhausted, a larger descriptor table

 * may be allocated, up to a process' resource limit; the internal arrays

 * are then unused.  The initial expansion is set to NDEXTENT; each time

 * it runs out, it is doubled until the resource limit is reached. NDEXTENT

 * should be selected to be the biggest multiple of OFILESIZE (see below)

 * that will fit in a power-of-two sized piece of memory.

 */

#define        NDFILE                20

#define        NDEXTENT        50                /* 250 bytes in 256-byte alloc */

#define        NDENTRIES        32                /* 32 fds per entry */

#define        NDENTRYMASK        (NDENTRIES - 1)

#define        NDENTRYSHIFT        5                /* bits per entry */

#define        NDLOSLOTS(x)        (((x) + NDENTRIES - 1) >> NDENTRYSHIFT)

#define        NDHISLOTS(x)        ((NDLOSLOTS(x) + NDENTRIES - 1) >> NDENTRYSHIFT)

#define        NDFDFILE        6                /* first 6 descriptors are free */

/*

 * Process-private descriptor reference, one for each descriptor slot

 * in use.  Locks:

 *

 * :        unlocked

 * a        atomic operations + filedesc_t::fd_lock in some cases

 * d        filedesc_t::fd_lock

 *

 * Note that ff_exclose and ff_allocated are likely to be byte sized

 * (bool).  In general adjacent sub-word sized fields must be locked

 * the same way, but in this case it's ok: ff_exclose can only be

 * modified while the descriptor slot is live, and ff_allocated when

 * it's invalid.

 */

typedef struct fdfile {

        bool                ff_exclose;        /* :: close on exec flag */

        bool                ff_allocated;        /* d: descriptor slot is allocated */

        u_int                ff_refcnt;        /* a: reference count on structure */

        struct file        *ff_file;        /* d: pointer to file if open */

        SLIST_HEAD(,knote) ff_knlist;        /* d: knotes attached to this fd */

        kcondvar_t        ff_closing;        /* d: notifier for close */

} fdfile_t;

/* Reference count */

#define        FR_CLOSING        (0x80000000)        /* closing: must interlock */

#define        FR_MASK                (~FR_CLOSING)        /* reference count */

/*

 * Open file table, potentially many 'active' tables per filedesc_t

 * in a multi-threaded process, or with a shared filedesc_t (clone()).

 * nfiles is first to avoid pointer arithmetic.

 */

typedef struct fdtab {

        u_int                dt_nfiles;        /* number of open files allocated */

        struct fdtab        *dt_link;        /* for lists of dtab */

        fdfile_t        *dt_ff[NDFILE];        /* file structures for open fds */

} fdtab_t;

typedef struct filedesc {

        /*

         * Built-in fdfile_t records first, since they have strict

         * alignment requirements.

         */

        uint8_t                fd_dfdfile[NDFDFILE][CACHE_LINE_SIZE];

        /*

         * All of the remaining fields are locked by fd_lock.

         */

        kmutex_t        fd_lock;        /* lock on structure */

        fdtab_t * volatile fd_dt;        /* active descriptor table */

        uint32_t        *fd_himap;        /* each bit points to 32 fds */

        uint32_t        *fd_lomap;        /* bitmap of free fds */

        struct klist        *fd_knhash;        /* hash of attached non-fd knotes */

        int                fd_lastkqfile;        /* max descriptor for kqueue */

        int                fd_lastfile;        /* high-water mark of fd_ofiles */

        int                fd_refcnt;        /* reference count */

        u_long                fd_knhashmask;        /* size of fd_knhash */

        int                fd_freefile;        /* approx. next free file */

        int                fd_unused;        /* unused */

        bool                fd_exclose;        /* non-zero if >0 fd with EXCLOSE */

        /*

         * This structure is used when the number of open files is

         * <= NDFILE, and are then pointed to by the pointers above.

         */

        fdtab_t                fd_dtbuiltin;

        /*

         * These arrays are used when the number of open files is

         * <= 1024, and are then pointed to by the pointers above.

         */

#define fd_startzero        fd_dhimap        /* area to zero on return to cache */

        uint32_t        fd_dhimap[NDENTRIES >> NDENTRYSHIFT];

        uint32_t        fd_dlomap[NDENTRIES];

} filedesc_t;

typedef struct cwdinfo {

        struct vnode        *cwdi_cdir;        /* current directory */

        struct vnode        *cwdi_rdir;        /* root directory */

        struct vnode        *cwdi_edir;        /* emulation root (if known) */

        krwlock_t        cwdi_lock;        /* lock on entire struct */

        u_short                cwdi_cmask;        /* mask for file creation */

        u_int                cwdi_refcnt;        /* reference count */

} cwdinfo_t;

#ifdef _KERNEL

struct fileops;

struct socket;

struct proc;

/*

 * Kernel global variables and routines.

 */

void        fd_sys_init(void);

int        fd_open(const char*, int, int, int*);

int        fd_dupopen(int, int *, int, int);

int        fd_alloc(struct proc *, int, int *);

void        fd_tryexpand(struct proc *);

int        fd_allocfile(file_t **, int *);

void        fd_affix(struct proc *, file_t *, unsigned);

void        fd_abort(struct proc *, file_t *, unsigned);

filedesc_t *fd_copy(void);

filedesc_t *fd_init(filedesc_t *);

void        fd_share(proc_t *);

void        fd_hold(lwp_t *);

void        fd_free(void);

void        fd_closeexec(void);

void        fd_ktrexecfd(void);

int        fd_checkstd(void);

file_t        *fd_getfile(unsigned);

file_t        *fd_getfile2(proc_t *, unsigned);

void        fd_putfile(unsigned);

int        fd_getvnode(unsigned, file_t **);

int        fd_getsock(unsigned, struct socket **);

int        fd_getsock1(unsigned, struct socket **, file_t **);

void        fd_putvnode(unsigned);

void        fd_putsock(unsigned);

int        fd_close(unsigned);

int        fd_dup(file_t *, int, int *, bool);

int        fd_dup2(file_t *, unsigned, int);

int        fd_clone(file_t *, unsigned, int, const struct fileops *, void *);

void        fd_set_exclose(struct lwp *, int, bool);

int        pipe1(struct lwp *, register_t *, int);

int        dodup(struct lwp *, int, int, int, register_t *);

void        cwd_sys_init(void);

struct cwdinfo *cwdinit(void);

void        cwdshare(proc_t *);

void        cwdunshare(proc_t *);

void        cwdfree(struct cwdinfo *);

void        cwdexec(struct proc *);

#define GETCWD_CHECK_ACCESS 0x0001

int        getcwd_common(struct vnode *, struct vnode *, char **, char *, int,

    int, struct lwp *);

int        vnode_to_path(char *, size_t, struct vnode *, struct lwp *,

    struct proc *);

int        closef(file_t *);

file_t *fgetdummy(void);

void        fputdummy(file_t *);

struct stat;

int        do_sys_fstat(int, struct stat *);

struct flock;

int        do_fcntl_lock(int, int, struct flock *);

int        do_posix_fadvise(int, off_t, off_t, int);

extern kmutex_t filelist_lock;

extern filedesc_t filedesc0;

#endif /* _KERNEL */

#endif /* !_SYS_FILEDESC_H_ */