*
* %sccs.include.redist.c%
*
- * @(#)union_vfsops.c 1.5 (Berkeley) %G%
+ * @(#)union_vfsops.c 8.2 (Berkeley) %G%
*/
/*
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/malloc.h>
-#include "union.h"
+#include <sys/filedesc.h>
+#include <sys/queue.h>
+#include <miscfs/union/union.h>
/*
* Mount union filesystem
{
int error = 0;
struct union_args args;
- struct vnode *lowerrootvp;
- struct vnode *upperrootvp;
+ struct vnode *lowerrootvp = NULLVP;
+ struct vnode *upperrootvp = NULLVP;
struct union_mount *um;
+ struct ucred *cred = 0;
+ char *cp;
+ int len;
u_int size;
#ifdef UNION_DIAGNOSTIC
* 1. a way to convert between rdonly and rdwr mounts.
* 2. support for nfs exports.
*/
- return (EOPNOTSUPP);
+ error = EOPNOTSUPP;
+ goto bad;
}
+ /*
+ * Take a copy of the process's credentials. This isn't
+ * quite right since the euid will always be zero and we
+ * want to get the "real" users credentials. So fix up
+ * the uid field after taking the copy.
+ */
+ cred = crdup(p->p_ucred);
+ cred->cr_uid = p->p_cred->p_ruid;
+
+ /*
+ * Ensure the *real* user has write permission on the
+ * mounted-on directory. This allows the mount_union
+ * command to be made setuid root so allowing anyone
+ * to do union mounts onto any directory on which they
+ * have write permission.
+ */
+ error = VOP_ACCESS(mp->mnt_vnodecovered, VWRITE, cred, p);
+ if (error)
+ goto bad;
+
/*
* Get argument
*/
if (error = copyin(data, (caddr_t)&args, sizeof(struct union_args)))
- return (error);
+ goto bad;
lowerrootvp = mp->mnt_vnodecovered;
VREF(lowerrootvp);
*/
NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT,
UIO_USERSPACE, args.target, p);
- if (error = namei(ndp)) {
- vrele(lowerrootvp);
- return (error);
- }
+ if (error = namei(ndp))
+ goto bad;
+
upperrootvp = ndp->ni_vp;
vrele(ndp->ni_dvp);
ndp->ni_dvp = NULL;
if (upperrootvp->v_type != VDIR) {
- vrele(upperrootvp);
- return (EINVAL);
+ error = EINVAL;
+ goto bad;
}
um = (struct union_mount *) malloc(sizeof(struct union_mount),
/*
* Keep a held reference to the target vnodes.
* They are vrele'd in union_unmount.
+ *
+ * Depending on the _BELOW flag, the filesystems are
+ * viewed in a different order. In effect, this is the
+ * same as providing a mount under option to the mount syscall.
*/
- um->um_lowervp = lowerrootvp;
- um->um_uppervp = upperrootvp;
+
+ switch (args.mntflags & UNMNT_OPMASK) {
+ case UNMNT_ABOVE:
+ um->um_lowervp = lowerrootvp;
+ um->um_uppervp = upperrootvp;
+ break;
+
+ case UNMNT_BELOW:
+ um->um_lowervp = upperrootvp;
+ um->um_uppervp = lowerrootvp;
+ break;
+
+ case UNMNT_REPLACE:
+ vrele(lowerrootvp);
+ lowerrootvp = NULLVP;
+ um->um_uppervp = upperrootvp;
+ um->um_lowervp = lowerrootvp;
+ break;
+
+ default:
+ error = EINVAL;
+ goto bad;
+ }
+
+ um->um_cred = cred;
+ um->um_cmode = UN_DIRMODE &~ p->p_fd->fd_cmask;
+
/*
- * Take a copy of the process's credentials. This isn't
- * quite right since the euid will always be zero and we
- * want to get the "real" users credentials. So fix up
- * the uid field after taking the copy.
+ * Depending on what you think the MNT_LOCAL flag might mean,
+ * you may want the && to be || on the conditional below.
+ * At the moment it has been defined that the filesystem is
+ * only local if it is all local, ie the MNT_LOCAL flag implies
+ * that the entire namespace is local. If you think the MNT_LOCAL
+ * flag implies that some of the files might be stored locally
+ * then you will want to change the conditional.
*/
- um->um_cred = crdup(p->p_ucred);
- um->um_cred->cr_uid = p->p_cred->p_ruid;
-
- if ((lowerrootvp->v_mount->mnt_flag & MNT_LOCAL) &&
- (upperrootvp->v_mount->mnt_flag & MNT_LOCAL))
+ if (((um->um_lowervp == NULLVP) ||
+ (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) &&
+ (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
mp->mnt_flag |= MNT_LOCAL;
+
/*
* Copy in the upper layer's RDONLY flag. This is for the benefit
* of lookup() which explicitly checks the flag, rather than asking
* mount of the underlying filesystem to go from rdonly to rdwr
* will leave the unioned view as read-only.
*/
- mp->mnt_flag |= (upperrootvp->v_mount->mnt_flag & MNT_RDONLY);
+ mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY);
mp->mnt_data = (qaddr_t) um;
getnewfsid(mp, MOUNT_UNION);
(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
- bcopy("union:", mp->mnt_stat.f_mntfromname, 6);
- (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname + 6,
- MNAMELEN - 1 - 6, &size);
- bzero(mp->mnt_stat.f_mntfromname + 6 + size, MNAMELEN - 6 - size);
+
+ switch (args.mntflags & UNMNT_OPMASK) {
+ case UNMNT_ABOVE:
+ cp = "un-above:";
+ break;
+ case UNMNT_BELOW:
+ cp = "un-below:";
+ break;
+ case UNMNT_REPLACE:
+ cp = "replace:";
+ break;
+ }
+ len = strlen(cp);
+ bcopy(cp, mp->mnt_stat.f_mntfromname, len);
+
+ cp = mp->mnt_stat.f_mntfromname + len;
+ len = MNAMELEN - len;
+
+ (void) copyinstr(args.target, cp, len - 1, &size);
+ bzero(cp + size, len - size);
+
#ifdef UNION_DIAGNOSTIC
- printf("union_mount: upper %s, lower at %s\n",
+ printf("union_mount: from %s, on %s\n",
mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
#endif
return (0);
+
+bad:
+ if (cred)
+ crfree(cred);
+ if (upperrootvp)
+ vrele(upperrootvp);
+ if (lowerrootvp)
+ vrele(lowerrootvp);
+ return (error);
}
/*
/*
* Discard references to upper and lower target vnodes.
*/
- vrele(um->um_lowervp);
+ if (um->um_lowervp)
+ vrele(um->um_lowervp);
vrele(um->um_uppervp);
crfree(um->um_cred);
/*
*/
free(mp->mnt_data, M_UFSMNT); /* XXX */
mp->mnt_data = 0;
- return 0;
+ return (0);
}
int
* Return locked reference to root.
*/
VREF(um->um_uppervp);
- VREF(um->um_lowervp);
+ VOP_LOCK(um->um_uppervp);
+ if (um->um_lowervp)
+ VREF(um->um_lowervp);
error = union_allocvp(vpp, mp,
(struct vnode *) 0,
(struct vnode *) 0,
if (error) {
vrele(um->um_uppervp);
- vrele(um->um_lowervp);
+ if (um->um_lowervp)
+ vrele(um->um_lowervp);
} else {
(*vpp)->v_flag |= VROOT;
}
bzero(&mstat, sizeof(mstat));
- error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p);
- if (error)
- return (error);
+ if (um->um_lowervp) {
+ error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p);
+ if (error)
+ return (error);
+ }
/* now copy across the "interesting" information and fake the rest */
#if 0