HAMMER 60I/Many: Mirroring

[dragonfly.git] / sys / vfs / fdesc / fdesc_vnops.c

/*
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software donated to Berkeley by
 * Jan-Simon Pendry.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 *
 *      @(#)fdesc_vnops.c       8.9 (Berkeley) 1/21/94
 *
 * $FreeBSD: src/sys/miscfs/fdesc/fdesc_vnops.c,v 1.47.2.1 2001/10/22 22:49:26 chris Exp $
 * $DragonFly: src/sys/vfs/fdesc/fdesc_vnops.c,v 1.39 2007/11/20 21:03:50 dillon Exp $
 */

/*
 * /dev/fd Filesystem
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/dirent.h>
#include <sys/filedesc.h>
#include <sys/kernel.h> /* boottime */
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/file.h>   /* Must come after sys/malloc.h */
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/vnode.h>
#include <sys/file2.h>

#include <machine/limits.h>

#include "fdesc.h"

#define FDL_WANT        0x01
#define FDL_LOCKED      0x02
static int fdcache_lock;

#define NFDCACHE 4
#define FD_NHASH(ix) \
        (&fdhashtbl[(ix) & fdhash])
static LIST_HEAD(fdhashhead, fdescnode) *fdhashtbl;
static u_long fdhash;

static int      fdesc_getattr (struct vop_getattr_args *ap);
static int      fdesc_inactive (struct vop_inactive_args *ap);
static int      fdesc_lookup (struct vop_old_lookup_args *ap);
static int      fdesc_open (struct vop_open_args *ap);
static int      fdesc_print (struct vop_print_args *ap);
static int      fdesc_readdir (struct vop_readdir_args *ap);
static int      fdesc_reclaim (struct vop_reclaim_args *ap);
static int      fdesc_poll (struct vop_poll_args *ap);
static int      fdesc_setattr (struct vop_setattr_args *ap);

/*
 * Initialise cache headers
 */
int
fdesc_init(struct vfsconf *vfsp)
{

        fdhashtbl = hashinit(NFDCACHE, M_CACHE, &fdhash);
        return (0);
}

int
fdesc_uninit(struct vfsconf *vfsp)
{
        if (fdhashtbl)
                kfree(fdhashtbl, M_CACHE);
        return (0);
}
int
fdesc_allocvp(fdntype ftype, int ix, struct mount *mp, struct vnode **vpp)
{
        struct fdhashhead *fc;
        struct fdescnode *fd;
        int error = 0;

        fc = FD_NHASH(ix);
loop:
        LIST_FOREACH(fd, fc, fd_hash) {
                if (fd->fd_ix == ix && fd->fd_vnode->v_mount == mp) {
                        if (vget(fd->fd_vnode, LK_EXCLUSIVE|LK_SLEEPFAIL))
                                goto loop;
                        *vpp = fd->fd_vnode;
                        return (error);
                }
        }

        /*
         * otherwise lock the array while we call getnewvnode
         * since that can block.
         */
        if (fdcache_lock & FDL_LOCKED) {
                fdcache_lock |= FDL_WANT;
                tsleep((caddr_t) &fdcache_lock, 0, "fdalvp", 0);
                goto loop;
        }
        fdcache_lock |= FDL_LOCKED;

        /*
         * Do the MALLOC before the getnewvnode since doing so afterward
         * might cause a bogus v_data pointer to get dereferenced
         * elsewhere if MALLOC should block.
         */
        MALLOC(fd, struct fdescnode *, sizeof(struct fdescnode), M_TEMP, M_WAITOK);

        error = getnewvnode(VT_FDESC, mp, vpp, 0, 0);
        if (error) {
                FREE(fd, M_TEMP);
                goto out;
        }
        (*vpp)->v_data = fd;
        fd->fd_vnode = *vpp;
        fd->fd_type = ftype;
        fd->fd_fd = -1;
        fd->fd_ix = ix;
        LIST_INSERT_HEAD(fc, fd, fd_hash);
        vx_unlock(*vpp);

out:
        fdcache_lock &= ~FDL_LOCKED;

        if (fdcache_lock & FDL_WANT) {
                fdcache_lock &= ~FDL_WANT;
                wakeup((caddr_t) &fdcache_lock);
        }

        return (error);
}

/*
 * vp is the current namei directory
 * ndp is the name to locate in that directory...
 *
 * fdesc_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
 *              struct componentname *a_cnp)
 */
static int
fdesc_lookup(struct vop_old_lookup_args *ap)
{
        struct componentname *cnp = ap->a_cnp;
        struct thread *td = cnp->cn_td;
        struct proc *p = td->td_proc;
        struct vnode **vpp = ap->a_vpp;
        struct vnode *dvp = ap->a_dvp;
        char *pname = cnp->cn_nameptr;
        int nlen = cnp->cn_namelen;
        int nfiles;
        u_int fd;
        int error;
        struct vnode *fvp;

        KKASSERT(p);
        nfiles = p->p_fd->fd_nfiles;
        if (cnp->cn_nameiop == NAMEI_DELETE || cnp->cn_nameiop == NAMEI_RENAME) {
                error = EROFS;
                goto bad;
        }

        vn_unlock(dvp);
        if (cnp->cn_namelen == 1 && *pname == '.') {
                *vpp = dvp;
                vref(dvp);      
                vn_lock(dvp, LK_SHARED | LK_RETRY);
                return (0);
        }

        if (VTOFDESC(dvp)->fd_type != Froot) {
                error = ENOTDIR;
                goto bad;
        }

        fd = 0;
        /* the only time a leading 0 is acceptable is if it's "0" */
        if (*pname == '0' && nlen != 1) {
                error = ENOENT;
                goto bad;
        }
        while (nlen--) {
                if (*pname < '0' || *pname > '9') {
                        error = ENOENT;
                        goto bad;
                }
                fd = 10 * fd + *pname++ - '0';
        }

        if (fd >= nfiles || p->p_fd->fd_files[fd].fp == NULL) {
                error = EBADF;
                goto bad;
        }

        error = fdesc_allocvp(Fdesc, FD_DESC+fd, dvp->v_mount, &fvp);
        if (error)
                goto bad;
        VTOFDESC(fvp)->fd_fd = fd;
        vn_lock(fvp, LK_SHARED | LK_RETRY);
        *vpp = fvp;
        return (0);

bad:
        vn_lock(dvp, LK_SHARED | LK_RETRY);
        *vpp = NULL;
        return (error);
}

/*
 * fdesc_open(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
 *            struct file *a_fp)
 */
static int
fdesc_open(struct vop_open_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct lwp *lp = curthread->td_lwp;

        KKASSERT(lp);

        if (VTOFDESC(vp)->fd_type == Froot)
                return (vop_stdopen(ap));

        /*
         * XXX Kludge: set lp->lwp_dupfd to contain the value of the the file
         * descriptor being sought for duplication. The error return ensures
         * that the vnode for this device will be released by vn_open. Open
         * will detect this special error and take the actions in dupfdopen.
         * Other callers of vn_open or VOP_OPEN will simply report the
         * error.
         */
        lp->lwp_dupfd = VTOFDESC(vp)->fd_fd;    /* XXX */
        return (ENODEV);
}

/*
 * fdesc_getattr(struct vnode *a_vp, struct vattr *a_vap, struct ucred *a_cred)
 */
static int
fdesc_getattr(struct vop_getattr_args *ap)
{
        struct proc *p = curproc;
        struct vnode *vp = ap->a_vp;
        struct vattr *vap = ap->a_vap;
        struct file *fp;
        struct stat stb;
        u_int fd;
        int error = 0;

        KKASSERT(p);

        switch (VTOFDESC(vp)->fd_type) {
        case Froot:
                VATTR_NULL(vap);

                vap->va_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH;
                vap->va_type = VDIR;
                vap->va_nlink = 2;
                vap->va_size = DEV_BSIZE;
                vap->va_fileid = VTOFDESC(vp)->fd_ix;
                vap->va_uid = 0;
                vap->va_gid = 0;
                vap->va_blocksize = DEV_BSIZE;
                vap->va_atime.tv_sec = boottime.tv_sec;
                vap->va_atime.tv_nsec = 0;
                vap->va_mtime = vap->va_atime;
                vap->va_ctime = vap->va_mtime;
                vap->va_gen = 0;
                vap->va_flags = 0;
                vap->va_rmajor = VNOVAL;
                vap->va_rminor = VNOVAL;
                vap->va_bytes = 0;
                break;

        case Fdesc:
                fd = VTOFDESC(vp)->fd_fd;

                fp = holdfp(p->p_fd, fd, -1);
                if (fp == NULL)
                        return (EBADF);

                bzero(&stb, sizeof(stb));
                error = fo_stat(fp, &stb, curproc->p_ucred);
                fdrop(fp);

                if (error == 0) {
                        VATTR_NULL(vap);
                        vap->va_type = IFTOVT(stb.st_mode);
                        vap->va_mode = stb.st_mode;
#define FDRX (VREAD|VEXEC)
                        if (vap->va_type == VDIR)
                                vap->va_mode &= ~((FDRX)|(FDRX>>3)|(FDRX>>6));
#undef FDRX
                        vap->va_nlink = 1;
                        vap->va_flags = 0;
                        vap->va_bytes = stb.st_blocks * stb.st_blksize;
                        vap->va_fileid = VTOFDESC(vp)->fd_ix;
                        vap->va_size = stb.st_size;
                        vap->va_blocksize = stb.st_blksize;
                        vap->va_rmajor = umajor(stb.st_rdev);
                        vap->va_rminor = uminor(stb.st_rdev);

                        /*
                         * If no time data is provided, use the current time.
                         */
                        if (stb.st_atimespec.tv_sec == 0 &&
                            stb.st_atimespec.tv_nsec == 0)
                                nanotime(&stb.st_atimespec);

                        if (stb.st_ctimespec.tv_sec == 0 &&
                            stb.st_ctimespec.tv_nsec == 0)
                                nanotime(&stb.st_ctimespec);

                        if (stb.st_mtimespec.tv_sec == 0 &&
                            stb.st_mtimespec.tv_nsec == 0)
                                nanotime(&stb.st_mtimespec);

                        vap->va_atime = stb.st_atimespec;
                        vap->va_mtime = stb.st_mtimespec;
                        vap->va_ctime = stb.st_ctimespec;
                        vap->va_uid = stb.st_uid;
                        vap->va_gid = stb.st_gid;
                }
                break;

        default:
                panic("fdesc_getattr");
                break;
        }

        if (error == 0)
                vp->v_type = vap->va_type;
        return (error);
}

/*
 * fdesc_setattr(struct vnode *a_vp, struct vattr *a_vap,
 *               struct ucred *a_cred)
 */
static int
fdesc_setattr(struct vop_setattr_args *ap)
{
        struct proc *p = curproc;
        struct vattr *vap = ap->a_vap;
        struct file *fp;
        unsigned fd;
        int error;

        /*
         * Can't mess with the root vnode
         */
        if (VTOFDESC(ap->a_vp)->fd_type == Froot)
                return (EACCES);

        fd = VTOFDESC(ap->a_vp)->fd_fd;
        KKASSERT(p);

        /*
         * Allow setattr where there is an underlying vnode.
         */
        error = holdvnode(p->p_fd, fd, &fp);
        if (error) {
                /*
                 * holdvnode() returns EINVAL if the file descriptor is not
                 * backed by a vnode.  Silently drop all changes except
                 * chflags(2) in this case.
                 */
                if (error == EINVAL) {
                        if (vap->va_flags != VNOVAL)
                                error = EOPNOTSUPP;
                        else
                                error = 0;
                }
        } else {
                fdrop(fp);
        }
        return (error);
}

#define UIO_MX 16

/*
 * fdesc_readdir(struct vnode *a_vp, struct uio *a_uio, struct ucred *a_cred,
 *               int *a_eofflag, off_t *a_cookies, int a_ncookies)
 */
static int
fdesc_readdir(struct vop_readdir_args *ap)
{
        struct uio *uio = ap->a_uio;
        struct filedesc *fdp;
        int error, i, fcnt;
        size_t namelen;
        char name[20]; /* enough for %d */

        /*
         * We don't allow exporting fdesc mounts, and currently local
         * requests do not need cookies.
         */
        if (ap->a_ncookies)
                panic("fdesc_readdir: not hungry");

        if (VTOFDESC(ap->a_vp)->fd_type != Froot)
                panic("fdesc_readdir: not dir");

        if (uio->uio_offset < 0 || uio->uio_offset > INT_MAX ||
            uio->uio_resid < 0)
                return(EINVAL);
        i = uio->uio_offset;
        KKASSERT(uio->uio_td->td_proc);
        fdp = uio->uio_td->td_proc->p_fd;
        error = 0;

        fcnt = i - 2;           /* The first two nodes are `.' and `..' */

        while (fcnt < fdp->fd_nfiles && uio->uio_resid > 0 && !error) {
                switch (i) {
                case 0: /* `.' */
                        if (vop_write_dirent(&error, uio, FD_ROOT + i, DT_DIR,
                                         1, "."))
                                goto done;
                        if (error)
                                return (error);
                        break;
                case 1: /* `..' */
                        if (vop_write_dirent(&error, uio, FD_ROOT + i, DT_DIR,
                                             2, ".."))
                                goto done;
                        if (error)
                                return (error);
                        break;
                default:
                        if (fdp->fd_files[fcnt].fp == NULL) {
                                fcnt++;
                                continue;
                        }

                        namelen = ksnprintf(name, sizeof(name), "%d", fcnt);
                        if (vop_write_dirent(&error, uio, FD_ROOT + i,
                                             DT_UNKNOWN, namelen, name))
                                goto done;
                        if (error)
                                return (error);
                        break;
                }
                i++;
                fcnt++;
        }

done:
        if (i >= 2)
                uio->uio_offset = fcnt + 2;
        else
                uio->uio_offset = i;
        return (error);
}

/*
 * fdesc_poll(struct vnode *a_vp, int a_events, struct ucred *a_cred)
 */
static int
fdesc_poll(struct vop_poll_args *ap)
{
        return seltrue(0, ap->a_events);
}

/*
 * fdesc_inactive(struct vnode *a_vp)
 */
static int
fdesc_inactive(struct vop_inactive_args *ap)
{
        struct vnode *vp = ap->a_vp;

        /*
         * Clear out the v_type field to avoid
         * nasty things happening in vgone().
         */
        vp->v_type = VNON;
        return (0);
}

/*
 * fdesc_reclaim(struct vnode *a_vp)
 */
static int
fdesc_reclaim(struct vop_reclaim_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct fdescnode *fd = VTOFDESC(vp);

        LIST_REMOVE(fd, fd_hash);
        FREE(vp->v_data, M_TEMP);
        vp->v_data = 0;

        return (0);
}

/*
 * Print out the contents of a /dev/fd vnode.
 *
 * fdesc_print(struct vnode *a_vp)
 */
/* ARGSUSED */
static int
fdesc_print(struct vop_print_args *ap)
{
        kprintf("tag VT_NON, fdesc vnode\n");
        return (0);
}

struct vop_ops fdesc_vnode_vops = {
        .vop_default =          vop_defaultop,
        .vop_access =           (void *)vop_null,
        .vop_getattr =          fdesc_getattr,
        .vop_inactive =         fdesc_inactive,
        .vop_old_lookup =       fdesc_lookup,
        .vop_open =             fdesc_open,
        .vop_pathconf =         vop_stdpathconf,
        .vop_poll =             fdesc_poll,
        .vop_print =            fdesc_print,
        .vop_readdir =          fdesc_readdir,
        .vop_reclaim =          fdesc_reclaim,
        .vop_setattr =          fdesc_setattr
};