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o Introduce vn_extattr_{get,set}, wrapper routines for VOP_GETEXTATTR

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and VOP_SETEXTATTR to simplify calling from in-kernel consumers,
  such as capability code.  Both accept a vnode (optionally locked,
  with ioflg to indicate that), attribute name, and a buffer + buffer
  length in UIO_SYSSPACE.  Both authorize the call as a kernel request,
  with cred set to NULL for the actual VOP_ calls.

Obtained from:	TrustedBSD Project
This commit is contained in:
Robert Watson 2000-08-08 17:15:32 +00:00
parent 320089a04a
commit e6a9ab52db
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=64405
2 changed files with 78 additions and 0 deletions
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74
sys/kern/vfs_vnops.c
View File

@ -873,3 +873,77 @@ filt_vnread(struct knote *kn, long hint)
kn->kn_data = ip->i_size - kn->kn_fp->f_offset;
return (kn->kn_data != 0);
}
/*
* Simplified in-kernel wrapper calls for extended attribute access.
* Both calls pass in a NULL credential, authorizing as "kernel" access.
* Set IO_NODELOCKED in ioflg if the vnode is already locked.
*/
int
vn_extattr_get(struct vnode *vp, int ioflg, const char *attrname, int *buflen,
char *buf, struct proc *p)
{
struct uio auio;
struct iovec iov;
int error;
iov.iov_len = *buflen;
iov.iov_base = buf;
auio.uio_iov = &iov;
auio.uio_iovcnt = 1;
auio.uio_rw = UIO_READ;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_procp = p;
auio.uio_offset = 0;
auio.uio_resid = *buflen;
if ((ioflg & IO_NODELOCKED) == 0)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
/* authorize attribute retrieval as kernel */
error = VOP_GETEXTATTR(vp, attrname, &auio, NULL, p);
if ((ioflg & IO_NODELOCKED) == 0)
VOP_UNLOCK(vp, 0, p);
if (error == 0) {
*buflen = *buflen - auio.uio_resid;
}
return (error);
}
/*
* XXX failure mode if partially written?
*/
int
vn_extattr_set(struct vnode *vp, int ioflg, const char *attrname, int buflen,
char *buf, struct proc *p)
{
struct uio auio;
struct iovec iov;
int error;
iov.iov_len = buflen;
iov.iov_base = buf;
auio.uio_iov = &iov;
auio.uio_iovcnt = 1;
auio.uio_rw = UIO_WRITE;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_procp = p;
auio.uio_offset = 0;
auio.uio_resid = buflen;
if ((ioflg & IO_NODELOCKED) == 0)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
/* authorize attribute setting as kernel */
error = VOP_SETEXTATTR(vp, attrname, &auio, NULL, p);
if ((ioflg & IO_NODELOCKED) == 0)
VOP_UNLOCK(vp, 0, p);
return (error);
}

4
sys/sys/vnode.h
View File

@ -596,6 +596,10 @@ dev_t vn_todev __P((struct vnode *vp));
int vn_write_suspend_wait __P((struct vnode *vp, struct mount *mp,
int flags));
int vn_writechk __P((struct vnode *vp));
int vn_extattr_get __P((struct vnode *vp, int ioflg, const char *attrname,
int *buflen, char *buf, struct proc *p));
int vn_extattr_set __P((struct vnode *vp, int ioflg, const char *attrname,
int buflen, char *buf, struct proc *p));
int vfs_cache_lookup __P((struct vop_lookup_args *ap));
int vfs_object_create __P((struct vnode *vp, struct proc *p,
struct ucred *cred));