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Annotation of sys/miscfs/specfs/spec_subr.c, Revision 1.1

1.1     ! nbrk        1: /*     $OpenBSD: spec_subr.c,v 1.2 2006/06/02 20:49:08 pedro Exp $     */
        !             2:
        !             3: /*
        !             4:  * Copyright (c) 2006 Pedro Martelletto <pedro@openbsd.org>
        !             5:  * Copyright (c) 2006 Thordur Bjornsson <thib@openbsd.org>
        !             6:  *
        !             7:  * Permission to use, copy, modify, and distribute this software for any
        !             8:  * purpose with or without fee is hereby granted, provided that the above
        !             9:  * copyright notice and this permission notice appear in all copies.
        !            10:  *
        !            11:  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
        !            12:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
        !            13:  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
        !            14:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
        !            15:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
        !            16:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
        !            17:  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
        !            18:  */
        !            19:
        !            20: #include <sys/param.h>
        !            21: #include <sys/vnode.h>
        !            22: #include <sys/malloc.h>
        !            23: #include <sys/conf.h>
        !            24: #include <sys/stat.h>
        !            25:
        !            26: #include <miscfs/specfs/specdev.h>
        !            27:
        !            28: int
        !            29: spec_open_clone(struct vop_open_args *ap)
        !            30: {
        !            31:        struct vnode *cvp, *vp = ap->a_vp;
        !            32:        struct cloneinfo *cip;
        !            33:        int error, i;
        !            34:
        !            35:        for (i = 1; i < sizeof(vp->v_specbitmap) * NBBY; i++)
        !            36:                if (isclr(vp->v_specbitmap, i)) {
        !            37:                        setbit(vp->v_specbitmap, i);
        !            38:                        break;
        !            39:                }
        !            40:
        !            41:        if (i == sizeof(vp->v_specbitmap) * NBBY)
        !            42:                return (EBUSY); /* too many open instances */
        !            43:
        !            44:        printf("spec_open_clone(): cloning device (%d, %d) for pid %u\n",
        !            45:            major(vp->v_rdev), minor(vp->v_rdev), curproc->p_pid);
        !            46:
        !            47:        error = cdevvp(makedev(major(vp->v_rdev), i), &cvp);
        !            48:        if (error)
        !            49:                return (error); /* out of vnodes */
        !            50:
        !            51:        VOP_UNLOCK(vp, 0, ap->a_p);
        !            52:
        !            53:        error = cdevsw[major(vp->v_rdev)].d_open(cvp->v_rdev, ap->a_mode,
        !            54:            S_IFCHR, ap->a_p);
        !            55:
        !            56:        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, ap->a_p);
        !            57:
        !            58:        if (error) {
        !            59:                 clrbit(vp->v_specbitmap, i);
        !            60:                 return (error); /* device open failed */
        !            61:        }
        !            62:
        !            63:        cip = malloc(sizeof(struct cloneinfo), M_TEMP, M_WAITOK);
        !            64:        cip->ci_data = vp->v_data;
        !            65:        cip->ci_vp = cvp;
        !            66:
        !            67:        cvp->v_specparent = vp;
        !            68:        vp->v_flag |= VCLONED;
        !            69:        vp->v_data = cip;
        !            70:
        !            71:        printf("spec_open_clone(): new minor for cloned device is %d\n",
        !            72:            minor(cvp->v_rdev));
        !            73:
        !            74:        return (0); /* device cloned */
        !            75: }
        !            76:
        !            77: int
        !            78: spec_close_clone(struct vop_close_args *ap)
        !            79: {
        !            80:        struct vnode *pvp, *vp = ap->a_vp;
        !            81:        int error;
        !            82:
        !            83:        error = cdevsw[major(vp->v_rdev)].d_close(vp->v_rdev, ap->a_fflag,
        !            84:            S_IFCHR, ap->a_p);
        !            85:        if (error)
        !            86:                return (error); /* device close failed */
        !            87:
        !            88:        pvp = vp->v_specparent; /* get parent device */
        !            89:        clrbit(pvp->v_specbitmap, minor(vp->v_rdev));
        !            90:
        !            91:        printf("spec_close_clone(): freeing minor %d of dev %d for"
        !            92:            " pid %u\n", minor(vp->v_rdev), major(vp->v_rdev), curproc->p_pid);
        !            93:
        !            94:        return (0); /* clone closed */
        !            95: }