Annotation of Net2/miscfs/fdesc/fdesc_vfsops.c, revision 1.1.1.2

1.1       root        1: /*
                      2:  * Copyright (c) 1990, 1992 Jan-Simon Pendry
                      3:  * All rights reserved.
                      4:  *
                      5:  * This code is derived from software contributed to Berkeley by
                      6:  * Jan-Simon Pendry.
                      7:  *
                      8:  * Redistribution and use in source and binary forms, with or without
                      9:  * modification, are permitted provided that the following conditions
                     10:  * are met:
                     11:  * 1. Redistributions of source code must retain the above copyright
                     12:  *    notice, this list of conditions and the following disclaimer.
                     13:  * 2. Redistributions in binary form must reproduce the above copyright
                     14:  *    notice, this list of conditions and the following disclaimer in the
                     15:  *    documentation and/or other materials provided with the distribution.
                     16:  * 3. All advertising materials mentioning features or use of this software
                     17:  *    must display the following acknowledgement:
                     18:  *      This product includes software developed by the University of
                     19:  *      California, Berkeley and its contributors.
                     20:  * 4. Neither the name of the University nor the names of its contributors
                     21:  *    may be used to endorse or promote products derived from this software
                     22:  *    without specific prior written permission.
                     23:  *
                     24:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     25:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     26:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     27:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     28:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     29:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     30:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     31:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     32:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     33:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     34:  * SUCH DAMAGE.
                     35:  *
1.1.1.2 ! root       36:  *     fdesc_vfsops.c,v 1.4 1993/06/07 05:25:20 cgd Exp
1.1       root       37:  */
                     38: 
                     39: /*
                     40:  * /dev/fd Filesystem
                     41:  */
                     42: 
                     43: #include "param.h"
                     44: #include "systm.h"
                     45: #include "time.h"
                     46: #include "types.h"
                     47: #include "proc.h"
                     48: #include "resourcevar.h"
                     49: #include "filedesc.h"
                     50: #include "vnode.h"
                     51: #include "mount.h"
                     52: #include "namei.h"
                     53: #include "malloc.h"
                     54: #include "miscfs/fdesc/fdesc.h"
                     55: 
                     56: static u_short fdesc_mntid;
                     57: 
                     58: fdesc_init()
                     59: {
                     60: #ifdef FDESC_DIAGNOSTIC
                     61:        printf("fdesc_init\n");         /* printed during system boot */
                     62: #endif
                     63: }
                     64: 
                     65: /*
                     66:  * Mount the per-process file descriptors (/dev/fd)
                     67:  */
                     68: fdesc_mount(mp, path, data, ndp, p)
                     69:        struct mount *mp;
                     70:        char *path;
                     71:        caddr_t data;
                     72:        struct nameidata *ndp;
                     73:        struct proc *p;
                     74: {
                     75:        int error = 0;
                     76:        u_int size;
                     77:        struct fdescmount *fmp;
                     78:        struct vnode *rvp;
                     79: 
                     80: #ifdef FDESC_DIAGNOSTIC
                     81:        printf("fdesc_mount(mp = %x)\n", mp);
                     82: #endif
                     83: 
                     84:        /*
                     85:         * Update is a no-op
                     86:         */
                     87:        if (mp->mnt_flag & MNT_UPDATE)
                     88:                return (EOPNOTSUPP);
                     89: 
1.1.1.2 ! root       90:        error = getnewvnode(VT_FDESC, mp, &fdesc_vnodeops, &rvp);
1.1       root       91:        if (error)
                     92:                return (error);
                     93: 
                     94:        fmp = (struct fdescmount *) malloc(sizeof(struct fdescmount),
1.1.1.2 ! root       95:                                 M_MISCFSMNT, M_WAITOK);
1.1       root       96:        rvp->v_type = VDIR;
                     97:        rvp->v_flag |= VROOT;
                     98:        /*VTOFDESC(rvp)->f_isroot = 1;*/
                     99: #ifdef FDESC_DIAGNOSTIC
                    100:        printf("fdesc_mount: root vp = %x\n", rvp);
                    101: #endif
                    102:        fmp->f_root = rvp;
                    103:        mp->mnt_flag |= MNT_LOCAL;
                    104:        mp->mnt_data = (qaddr_t) fmp;
                    105:        getnewfsid(mp, MOUNT_FDESC);
                    106: 
                    107:        (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
                    108:        bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
                    109:        bzero(mp->mnt_stat.f_mntfromname, MNAMELEN);
                    110:        bcopy("fdesc", mp->mnt_stat.f_mntfromname, sizeof("fdesc"));
                    111: #ifdef FDESC_DIAGNOSTIC
                    112:        printf("fdesc_mount: at %s\n", mp->mnt_stat.f_mntonname);
                    113: #endif
                    114:        return (0);
                    115: }
                    116: 
                    117: fdesc_start(mp, flags, p)
                    118:        struct mount *mp;
                    119:        int flags;
                    120:        struct proc *p;
                    121: {
                    122:        return (0);
                    123: }
                    124: 
                    125: fdesc_unmount(mp, mntflags, p)
                    126:        struct mount *mp;
                    127:        int mntflags;
                    128:        struct proc *p;
                    129: {
                    130:        int error;
                    131:        int flags = 0;
                    132:        extern int doforce;
                    133:        struct vnode *rootvp = VFSTOFDESC(mp)->f_root;
                    134: 
                    135: #ifdef FDESC_DIAGNOSTIC
                    136:        printf("fdesc_unmount(mp = %x)\n", mp);
                    137: #endif
                    138: 
                    139:        if (mntflags & MNT_FORCE) {
                    140:                /* fdesc can never be rootfs so don't check for it */
                    141:                if (!doforce)
                    142:                        return (EINVAL);
                    143:                flags |= FORCECLOSE;
                    144:        }
                    145: 
                    146:        /*
                    147:         * Clear out buffer cache.  I don't think we
                    148:         * ever get anything cached at this level at the
                    149:         * moment, but who knows...
                    150:         */
                    151: #ifdef FDESC_DIAGNOSTIC
                    152:        printf("fdesc_unmount: calling mntflushbuf\n");
                    153: #endif
                    154:        mntflushbuf(mp, 0); 
                    155: #ifdef FDESC_DIAGNOSTIC
                    156:        printf("fdesc_unmount: calling mntinvalbuf\n");
                    157: #endif
                    158:        if (mntinvalbuf(mp, 1))
                    159:                return (EBUSY);
                    160:        if (rootvp->v_usecount > 1)
                    161:                return (EBUSY);
                    162: #ifdef FDESC_DIAGNOSTIC
                    163:        printf("fdesc_unmount: calling vflush\n");
                    164: #endif
                    165:        if (error = vflush(mp, rootvp, flags))
                    166:                return (error);
                    167: 
                    168: #ifdef FDESC_DIAGNOSTIC
                    169:        vprint("fdesc root", rootvp);
                    170: #endif  
                    171:        /*
                    172:         * Release reference on underlying root vnode
                    173:         */
                    174:        vrele(rootvp);
                    175:        /*
                    176:         * And blow it away for future re-use
                    177:         */
                    178:        vgone(rootvp);
                    179:        /*
                    180:         * Finally, throw away the fdescmount structure
                    181:         */
1.1.1.2 ! root      182:        free(mp->mnt_data, M_MISCFSMNT);
1.1       root      183:        mp->mnt_data = 0;
                    184:        return 0;
                    185: }
                    186: 
                    187: fdesc_root(mp, vpp)
                    188:        struct mount *mp;
                    189:        struct vnode **vpp;
                    190: {
                    191:        struct vnode *vp;
                    192:        int error;
                    193: 
                    194: #ifdef FDESC_DIAGNOSTIC
                    195:        printf("fdesc_root(mp = %x)\n", mp);
                    196: #endif
                    197: 
                    198:        /*
                    199:         * Return locked reference to root.
                    200:         */
                    201:        vp = VFSTOFDESC(mp)->f_root;
                    202:        VREF(vp);
                    203:        VOP_LOCK(vp);
                    204:        *vpp = vp;
                    205:        return (0);
                    206: }
                    207: 
                    208: fdesc_quotactl(mp, cmd, uid, arg, p)
                    209:        struct mount *mp;
                    210:        int cmd;
                    211:        uid_t uid;
                    212:        caddr_t arg;
                    213:        struct proc *p;
                    214: {
                    215:        return (EOPNOTSUPP);
                    216: }
                    217: 
                    218: fdesc_statfs(mp, sbp, p)
                    219:        struct mount *mp;
                    220:        struct statfs *sbp;
                    221:        struct proc *p;
                    222: {
                    223:        struct filedesc *fdp;
                    224:        int lim;
                    225:        int i;
                    226:        int last;
                    227:        int freefd;
                    228: 
                    229: #ifdef FDESC_DIAGNOSTIC
                    230:        printf("fdesc_statfs(mp = %x)\n", mp);
                    231: #endif
                    232: 
                    233:        /*
                    234:         * Compute number of free file descriptors.
                    235:         * [ Strange results will ensue if the open file
                    236:         * limit is ever reduced below the current number
                    237:         * of open files... ]
                    238:         */
                    239:        lim = p->p_rlimit[RLIMIT_OFILE].rlim_cur;
                    240:        fdp = p->p_fd;
                    241:        last = min(fdp->fd_nfiles, lim);
                    242:        freefd = 0;
                    243:        for (i = fdp->fd_freefile; i < last; i++)
                    244:                if (fdp->fd_ofiles[i] == NULL)
                    245:                        freefd++;
                    246: 
                    247:        /*
                    248:         * Adjust for the fact that the fdesc array may not
                    249:         * have been fully allocated yet.
                    250:         */
                    251:        if (fdp->fd_nfiles < lim)
                    252:                freefd += (lim - fdp->fd_nfiles);
                    253: 
                    254:        sbp->f_type = MOUNT_FDESC;
                    255:        sbp->f_flags = 0;
                    256:        sbp->f_fsize = DEV_BSIZE;
                    257:        sbp->f_bsize = DEV_BSIZE;
                    258:        sbp->f_blocks = 2;              /* 1K to keep df happy */
                    259:        sbp->f_bfree = 0;
                    260:        sbp->f_bavail = 0;
                    261:        sbp->f_files = lim + 1;         /* Allow for "." */
                    262:        sbp->f_ffree = freefd;          /* See comments above */
                    263:        if (sbp != &mp->mnt_stat) {
                    264:                bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
                    265:                bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
                    266:                bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
                    267:        }
                    268:        return (0);
                    269: }
                    270: 
                    271: fdesc_sync(mp, waitfor)
                    272:        struct mount *mp;
                    273:        int waitfor;
                    274: {
                    275:        return (0);
                    276: }
                    277: 
                    278: fdesc_fhtovp(mp, fhp, vpp)
                    279:        struct mount *mp;
                    280:        struct fid *fhp;
                    281:        struct vnode **vpp;
                    282: {
                    283:        return (EOPNOTSUPP);
                    284: }
                    285: 
                    286: fdesc_vptofh(vp, fhp)
                    287:        struct vnode *vp;
                    288:        struct fid *fhp;
                    289: {
                    290:        return (EOPNOTSUPP);
                    291: }
                    292: 
                    293: struct vfsops fdesc_vfsops = {
                    294:        fdesc_mount,
                    295:        fdesc_start,
                    296:        fdesc_unmount,
                    297:        fdesc_root,
                    298:        fdesc_quotactl,
                    299:        fdesc_statfs,
                    300:        fdesc_sync,
                    301:        fdesc_fhtovp,
                    302:        fdesc_vptofh,
                    303:        fdesc_init,
                    304: };

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