Porting from null layer

[unix-history] / usr / src / sys / miscfs / umapfs / umap_vnops.c

/*
* Copyright (c) 1992 The Regents of the University of California
* All rights reserved.
*
* This code is derived from software donated to Berkeley by
* the UCLA Ficus project.
*
* %sccs.include.redist.c%
*
*      @(#)umap_vnops.c        1.2 (Berkeley) %G%
*
* @(#)umap_vnops.c       1.5 (Berkeley) 7/10/92
*/

/*
* Umap Layer
*/

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <umapfs/umap.h>


int umap_bug_bypass = 0;   /* for debugging: enables bypass printf'ing */

/*
* This is the 10-Apr-92 bypass routine.
* See null_vnops.c:null_bypass for more details.
*/ 
int
umap_bypass(ap)
       struct vop_generic_args *ap;
{
       extern int (**umap_vnodeop_p)();  /* not extern, really "forward" */
       int *mapdata, nentries ;
       int *gmapdata, gnentries ;
       struct ucred **credpp,*credp, *savecredp, *saveucredp, *savecompcredp ;
       struct ucred *compcredp;
       register struct vnode **this_vp_p;
       int error;
       struct vnode *old_vps[VDESC_MAX_VPS], *vp1;
       struct vnode **vps_p[VDESC_MAX_VPS];
       struct vnode ***vppp;
       struct vnodeop_desc *descp = ap->a_desc;
       int reles, i;
       struct componentname **compnamepp;

       if (umap_bug_bypass)
               printf ("umap_bypass: %s\n", descp->vdesc_name);

#ifdef SAFETY
       /*
        * We require at least one vp.
        */
       if (descp->vdesc_vp_offsets == NULL ||
           descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
               panic ("umap_bypass: no vp's in map.\n");
#endif

       /*
        * Map the vnodes going in.
        * Later, we'll invoke the operation based on
        * the first mapped vnode's operation vector.
        */
       reles = descp->vdesc_flags;
       for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
               if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
                       break;   /* bail out at end of list */
               vps_p[i] = this_vp_p = 
                       VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap);

               if (i == 0)
               {
                       vp1 = *vps_p[0];
               }

               /*
                * We're not guaranteed that any but the first vnode
                * are of our type.  Check for and don't map any
                * that aren't.  (Must map first vp or vclean fails.)
                */

               if (i && (*this_vp_p)->v_op != umap_vnodeop_p) {
                       old_vps[i] = NULL;
               } else {
                       old_vps[i] = *this_vp_p;
                       *(vps_p[i]) = UMAPVPTOLOWERVP(*this_vp_p);
                       if (reles & 1)
                               VREF(*this_vp_p);
               }
                       
       }

       /*
        * Fix the credentials.  (That's the purpose of this layer.)
        */

       if (descp->vdesc_cred_offset != VDESC_NO_OFFSET) {

               credpp = VOPARG_OFFSETTO(struct ucred**, 
                   descp->vdesc_cred_offset, ap);

               /* Save old values */

               savecredp = (*credpp);
               (*credpp) = crdup(savecredp);
               credp = *credpp;

               if (umap_bug_bypass && credp->cr_uid != 0 )
                       printf("umap_bypass: user was %d, group %d\n", 
                           credp->cr_uid,credp->cr_gid);

               /* Map all ids in the credential structure. */

               umap_mapids(vp1->v_mount,credp);

               if (umap_bug_bypass && credp->cr_uid != 0 )
                       printf("umap_bypass: user now %d, group %d\n", 
                           credp->cr_uid,credp->cr_gid);
       }

       /* BSD often keeps a credential in the componentname structure
        * for speed.  If there is one, it better get mapped, too. 
        */

       if (descp->vdesc_componentname_offset != VDESC_NO_OFFSET) {

               compnamepp = VOPARG_OFFSETTO(struct componentname**, 
                   descp->vdesc_componentname_offset, ap);

               compcredp = (*compnamepp)->cn_cred;
               savecompcredp = compcredp;
               compcredp = (*compnamepp)->cn_cred = crdup(savecompcredp);

               if (umap_bug_bypass && compcredp->cr_uid != 0 )
                       printf("umap_bypass: component credit user was %d, group %d\n", 
                           compcredp->cr_uid,compcredp->cr_gid);

               /* Map all ids in the credential structure. */

               umap_mapids(vp1->v_mount,compcredp);

               if (umap_bug_bypass && compcredp->cr_uid != 0 )
                       printf("umap_bypass: component credit user now %d, group %d\n", 
                           compcredp->cr_uid,compcredp->cr_gid);
       }

       /*
        * Call the operation on the lower layer
        * with the modified argument structure.
        */
       error = VCALL(*(vps_p[0]), descp->vdesc_offset, ap);

       /*
        * Maintain the illusion of call-by-value
        * by restoring vnodes in the argument structure
        * to their original value.
        */
       reles = descp->vdesc_flags;
       for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
               if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
                       break;   /* bail out at end of list */
               if (old_vps[i]) {
                       *(vps_p[i]) = old_vps[i];
                       if (reles & 1)
                               vrele(*(vps_p[i]));
               };
       };

       /*
        * Map the possible out-going vpp
        * (Assumes that the lower layer always returns
        * a VREF'ed vpp unless it gets an error.)
        */
       if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET &&
           !(descp->vdesc_flags & VDESC_NOMAP_VPP) &&
           !error) {
               if (descp->vdesc_flags & VDESC_VPP_WILLRELE)
                       goto out;
               vppp = VOPARG_OFFSETTO(struct vnode***,
                                descp->vdesc_vpp_offset,ap);
               error = umap_node_create(old_vps[0]->v_mount, **vppp, *vppp);
       };

out:
       /* 
        * Free duplicate cred structure and restore old one.
        */
       if (descp->vdesc_cred_offset != VDESC_NO_OFFSET) {
               if (umap_bug_bypass && credp->cr_uid != 0 )
               printf("umap_bypass: returning-user was %d\n", credp->cr_uid);

               crfree(credp);
               (*credpp) = savecredp;
               if (umap_bug_bypass && (*credpp)->cr_uid != 0 )
                       printf("umap_bypass: returning-user now %d\n\n", 
                           (*credpp)->cr_uid);
       }

       if (descp->vdesc_componentname_offset != VDESC_NO_OFFSET) {
               if (umap_bug_bypass && compcredp->cr_uid != 0 )
               printf("umap_bypass: returning-component-user was %d\n", 
                   compcredp->cr_uid);

               crfree(compcredp);
               (*compnamepp)->cn_cred = savecompcredp;
               if (umap_bug_bypass && (*credpp)->cr_uid != 0 )
                       printf("umap_bypass: returning-component-user now %d\n\n", 
                           compcredp->cr_uid);
       }

       return (error);
}


/*
*  We handle getattr to change the fsid.
*/
int
umap_getattr(ap)
       struct vop_getattr_args *ap;
{
       short uid, gid;
       int error, tmpid, *mapdata, nentries, *gmapdata, gnentries;
       struct vnode **vp1p;
       struct vnodeop_desc *descp = ap->a_desc;

       if (error = umap_bypass(ap))
               return error;
       /* Requires that arguments be restored. */
       ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];

       /*
        * Umap needs to map the uid and gid returned by a stat
        * into the proper values for this site.  This involves
        * finding the returned uid in the mapping information,
        * translating it into the uid on the other end,
        * and filling in the proper field in the vattr
        * structure pointed to by ap->a_vap.  The group
        * is easier, since currently all groups will be
        * translate to the NULLGROUP.
        */

       /* Find entry in map */

       uid = ap->a_vap->va_uid;
       gid = ap->a_vap->va_gid;
       if (umap_bug_bypass)
               printf("umap_getattr: mapped uid = %d, mapped gid = %d\n",uid, 
                   gid);

       vp1p = VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[0],ap);
       nentries =  MOUNTTOUMAPMOUNT((*vp1p)->v_mount)->info_nentries;
       mapdata =  &(MOUNTTOUMAPMOUNT((*vp1p)->v_mount)->info_mapdata[0][0]);
       gnentries =  MOUNTTOUMAPMOUNT((*vp1p)->v_mount)->info_gnentries;
       gmapdata =  &(MOUNTTOUMAPMOUNT((*vp1p)->v_mount)->info_gmapdata[0][0]);

       /* Reverse map the uid for the vnode.  Since it's a reverse
               map, we can't use umap_mapids() to do it. */

       tmpid = umap_reverse_findid(uid,mapdata,nentries);

       if (tmpid != -1 ) {

               ap->a_vap->va_uid = (uid_t)tmpid;
               if (umap_bug_bypass)
                       printf("umap_getattr: original uid = %d\n",uid);
       } else 
               ap->a_vap->va_uid = (uid_t)NOBODY;

       /* Reverse map the gid for the vnode. */

       tmpid = umap_reverse_findid(gid,gmapdata,gnentries);

       if (tmpid != -1) {

               ap->a_vap->va_gid = (gid_t)tmpid;
               if (umap_bug_bypass)
                       printf("umap_getattr: original gid = %d\n",gid);
       } else
               ap->a_vap->va_gid = (gid_t)NULLGROUP;
       
       return 0;
}

int
umap_inactive (ap)
       struct vop_inactive_args *ap;
{
       /*
        * Do nothing (and _don't_ bypass).
        * Wait to vrele lowervp until reclaim,
        * so that until then our umap_node is in the
        * cache and reusable.
        *
        */
       return 0;
}

int
umap_reclaim (ap)
       struct vop_reclaim_args *ap;
{
       struct vnode *vp = ap->a_vp;
       struct umap_node *xp = VTOUMAP(vp);
       struct vnode *lowervp = xp->umap_lowervp;
       
       /* After this assignment, this node will not be re-used. */
       xp->umap_lowervp = NULL;
       remque(xp);
       FREE(vp->v_data, M_TEMP);
       vp->v_data = NULL;
       vrele (lowervp);
       return 0;
}

int
umap_strategy (ap)
       struct vop_strategy_args *ap;
{
       struct buf *bp = ap->a_bp;
       int error;
       struct vnode *savedvp;

       savedvp = bp->b_vp;
       bp->b_vp = UMAPVPTOLOWERVP(bp->b_vp);

       error = VOP_STRATEGY(ap->a_bp);

       bp->b_vp = savedvp;

       return error;
}

int
umap_bwrite (ap)
       struct vop_bwrite_args *ap;
{
       struct buf *bp = ap->a_bp;
       int error;
       struct vnode *savedvp;

       savedvp = bp->b_vp;
       bp->b_vp = UMAPVPTOLOWERVP(bp->b_vp);

       error = VOP_BWRITE(ap->a_bp);

       bp->b_vp = savedvp;

       return error;
}


int
umap_print (ap)
       struct vop_print_args *ap;
{
       register struct vnode *vp = ap->a_vp;
       printf ("\ttag VT_UMAPFS, vp=%x, lowervp=%x\n", vp, UMAPVPTOLOWERVP(vp));
       return 0;
}

int
umap_rename(ap)
       struct vop_rename_args *ap;
{
       int error;
       struct componentname *compnamep;
       struct ucred *compcredp, *savecompcredp;
       struct vnode *vp;

       /* Now map the second componentname structure kept in this vop's
        * arguments. 
        */

       vp = ap->a_fdvp;
       compnamep = ap->a_tcnp;
       compcredp = compnamep->cn_cred;

       savecompcredp = compcredp;
       compcredp = compnamep->cn_cred = crdup(savecompcredp);

       if (umap_bug_bypass && compcredp->cr_uid != 0 )
               printf("umap_rename: rename component credit user was %d, group %d\n", 
                   compcredp->cr_uid,compcredp->cr_gid);

       /* Map all ids in the credential structure. */

       umap_mapids(vp->v_mount,compcredp);

       if (umap_bug_bypass && compcredp->cr_uid != 0 )
               printf("umap_rename: rename component credit user now %d, group %d\n", 
                   compcredp->cr_uid,compcredp->cr_gid);

       if (error = umap_bypass(ap))
               return error;
       
       /* Restore the additional mapped componentname cred structure. */

       crfree(compcredp);
       compnamep->cn_cred = savecompcredp;
       
}

/*
* Global vfs data structures
*/
/*
* XXX - strategy,bwrite are hand coded currently.  They should
* go away with a merged buffer/block cache.
*
*/
int (**umap_vnodeop_p)();
struct vnodeopv_entry_desc umap_vnodeop_entries[] = {
       { &vop_default_desc, umap_bypass },

       { &vop_getattr_desc, umap_getattr },
       { &vop_inactive_desc, umap_inactive },
       { &vop_reclaim_desc, umap_reclaim },
       { &vop_print_desc, umap_print },

       { &vop_strategy_desc, umap_strategy },
       { &vop_bwrite_desc, umap_bwrite },

       { (struct vnodeop_desc*)NULL, (int(*)())NULL }
};
struct vnodeopv_desc umap_vnodeop_opv_desc =
       { &umap_vnodeop_p, umap_vnodeop_entries };