Date: Wed, 23 May 2001 14:20:54 +0400 (MSD) From: "Vladimir B. Grebenschikov" <vova@vbook.express.ru> To: FreeBSD-gnats-submit@freebsd.org Subject: kern/27571: Changing policy of shadowing files and directoris to upper layer in unionfs Message-ID: <200105231020.OAA01356@vbook.express.ru>
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>Number: 27571
>Category: kern
>Synopsis: Changing policy of shadowing files and directoris to upper layer in unionfs
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: change-request
>Submitter-Id: current-users
>Arrival-Date: Wed May 23 03:30:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator: Vladimir B. Grebenschikov
>Release: FreeBSD 4.3-RELEASE i386
>Organization:
TSB "Russian Express"
>Environment:
FreeBSD wda0.express.ru 4.3-RELEASE FreeBSD 4.3-RELEASE #2: Wed May 23 11:22:45
MSD 2001 root@wda0.express.ru:/usr/src/sys/compile/WDA0 i386
>Description:
While working with unionfs:
If a directory is found in the lower layer, and there is no entry in the
upper layer, then a shadow directory will be created in the upperlayer.
It will be owned by the user who originally did the union mount, with
mode `rwxrwxrwx'' (0777) modified by the umask in effect at that time.
So inbasic unionfs policy do all think like user copy directory structure
by his own hand.
I want possibility to give user exactly same stucture as on below layer,
with same uid/gid/mode as on lowerlayer.
Patch attached provide possibility use -a key to /sbin/mount_union.
In case of the -a option the newly mirrored upper-layer directory will
have the same attributes as the lower-layer directory.
And same thing with files.
>How-To-Repeat:
>Fix:
--- /usr/src/sbin/mount_union/mount_union.c Sat Oct 9 15:54:14 1999
+++ sbin/mount_union/mount_union.c Tue May 22 15:21:46 2001
@@ -85,7 +85,7 @@
mntflags = 0;
args.mntflags = UNMNT_ABOVE;
- while ((ch = getopt(argc, argv, "bo:r")) != -1)
+ while ((ch = getopt(argc, argv, "abo:r")) != -1)
switch (ch) {
case 'b':
args.mntflags &= ~UNMNT_OPMASK;
@@ -97,6 +97,9 @@
case 'r':
args.mntflags &= ~UNMNT_OPMASK;
args.mntflags |= UNMNT_REPLACE;
+ break;
+ case 'a':
+ args.mntflags |= UNMNT_CPATTR;
break;
case '?':
default:
--- /usr/src/sbin/mount_union/mount_union.8 Wed May 23 14:08:09 2001
+++ sbin/mount_union/mount_union.8 Wed May 23 14:05:21 2001
@@ -43,7 +43,7 @@
.Nd mount union filesystems
.Sh SYNOPSIS
.Nm
-.Op Fl br
+.Op Fl bra
.Op Fl o Ar options
.Ar directory
.Ar uniondir
@@ -87,6 +87,9 @@
.It Fl r
Hide the lower layer completely in the same way as mounting with
.Xr mount_null 8 .
+.It Fl a
+Changes the policy of attributes set up during the creation of a new
+upper-layer shadow file or directory.
.El
.Pp
To enforce filesystem security, the user mounting the filesystem
@@ -103,6 +106,8 @@
with mode
.Dq rwxrwxrwx
(0777) modified by the umask in effect at that time.
+In case of the -a option the newly created upper-layer directory will have
+the same attributes as the lower-layer directory.
.Pp
If a file exists in the upper layer then there is no way to access
a file with the same name in the lower layer.
--- /usr/src/sys/miscfs/union/union.h Wed Dec 29 07:54:48 1999
+++ sys/miscfs/union/union.h Tue May 22 15:04:40 2001
@@ -48,12 +48,15 @@
#define UNMNT_REPLACE 0x0003 /* Target replaces mount point */
#define UNMNT_OPMASK 0x0003
+#define UNMNT_CPATTR 0x0004
+
struct union_mount {
struct vnode *um_uppervp; /* UN_ULOCK holds locking state */
struct vnode *um_lowervp; /* Left unlocked */
struct ucred *um_cred; /* Credentials of user calling mount */
int um_cmode; /* cmask from mount process */
int um_op; /* Operation mode */
+ int um_flag;
};
#ifdef _KERNEL
--- /usr/src/sys/miscfs/union/union_subr.c Thu Dec 16 02:02:12 1999
+++ sys/miscfs/union/union_subr.c Tue May 22 15:11:14 2001
@@ -749,6 +756,9 @@
int error;
struct vnode *lvp, *uvp;
+ struct union_mount *um;
+
+ um = MOUNTTOUNIONMOUNT(UNIONTOV(un)->v_mount);
/*
* If the user does not have read permission, the vnode should not
* be copied to upper layer.
@@ -784,6 +794,26 @@
UDEBUG(("union: copied up %s\n", un->un_path));
}
+ if(error == 0 && um->um_flag & UNMNT_CPATTR){
+ struct vattr loattr, newattr;
+ int aerror;
+ struct ucred cred;
+
+ VATTR_NULL(&loattr);
+ cred.cr_ref = 1;
+ cred.cr_uid = 0;
+ cred.cr_ngroups = 1;
+ cred.cr_groups[0] = 0;
+ cred.cr_uidinfo = 0;
+ aerror = VOP_GETATTR(lvp, &loattr, &cred, p);
+ if(aerror == 0) {
+ VATTR_NULL(&newattr);
+ newattr.va_uid = loattr.va_uid;
+ newattr.va_gid = loattr.va_gid;
+ aerror = VOP_SETATTR(uvp, &newattr, &cred, p);
+ }
+ }
+out:;
VOP_UNLOCK(uvp, 0, p);
union_newupper(un, uvp);
KASSERT(uvp->v_usecount > 0, ("copy: uvp refcount 0: %d", uvp->v_usecount));
--- /usr/src/sys/miscfs/union/union_vfsops.c Sun Dec 19 09:07:52 1999
+++ sys/miscfs/union/union_vfsops.c Tue May 22 15:12:36 2001
@@ -185,6 +185,7 @@
bzero(um, sizeof(struct union_mount));
um->um_op = args.mntflags & UNMNT_OPMASK;
+ um->um_flag = args.mntflags;
switch (um->um_op) {
case UNMNT_ABOVE:
--- /usr/src/sys/miscfs/union/union_vnops.c Thu Dec 16 02:02:14 1999
+++ sys/miscfs/union/union_vnops.c Tue May 22 15:14:31 2001
@@ -506,6 +516,10 @@
/* case 2. */
if (uerror != 0 /* && (lerror == 0) */ ) {
if (lowervp->v_type == VDIR) { /* case 2b. */
+ struct vattr loattr, newattr;
+ int aerror;
+ struct ucred cred;
+
KASSERT(uppervp == NULL, ("uppervp unexpectedly non-NULL"));
/*
* oops, uppervp has a problem, we may have to shadow.
@@ -515,6 +529,21 @@
error = uerror;
goto out;
}
+ if(um->um_flag & UNMNT_CPATTR) {
+ VATTR_NULL(&loattr);
+ cred.cr_ref = 1;
+ cred.cr_uid = 0;
+ cred.cr_ngroups = 1;
+ cred.cr_groups[0] = 0;
+ cred.cr_uidinfo = 0;
+ aerror = VOP_GETATTR(lowervp, &loattr, &cred, cnp->cn_proc);
+ if(aerror == 0) {
+ VATTR_NULL(&newattr);
+ newattr.va_uid = loattr.va_uid;
+ newattr.va_gid = loattr.va_gid;
+ aerror = VOP_SETATTR(uppervp, &newattr, &cred, p);
+ }
+ }
}
}
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