text: /*-
   * Copyright (c) 1999, 2000 Robert N. M. Watson
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * $FreeBSD: src/sys/kern/kern_acl.c,v 1.2.2.1 2000/07/28 18:48:16 rwatson Exp $
   * $DragonFly: src/sys/kern/kern_acl.c,v 1.17 2007/02/19 00:51:54 swildner Exp $
   */
  
  /*
   * Generic routines to support file system ACLs, at a syntactic level
   * Semantics are the responsibility of the underlying file system
   */
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/sysproto.h>
  #include <sys/kernel.h>
  #include <sys/malloc.h>
  #include <sys/vnode.h>
  #include <sys/lock.h>
  #include <sys/proc.h>
  #include <sys/nlookup.h>
  #include <sys/file.h>
  #include <sys/sysent.h>
  #include <sys/errno.h>
  #include <sys/stat.h>
  #include <sys/acl.h>
  
  #include <sys/mplock2.h>
  
  static int vacl_set_acl(struct vnode *vp, acl_type_t type, struct acl *aclp);
  static int vacl_get_acl(struct vnode *vp, acl_type_t type, struct acl *aclp);
  static int vacl_aclcheck(struct vnode *vp, acl_type_t type, struct acl *aclp);
  
  /*
   * These calls wrap the real vnode operations, and are called by the 
   * syscall code once the syscall has converted the path or file
   * descriptor to a vnode (unlocked).  The aclp pointer is assumed
   * still to point to userland, so this should not be consumed within
   * the kernel except by syscall code.  Other code should directly
   * invoke VOP_{SET,GET}ACL.
   */
  
  /*
   * Given a vnode, set its ACL.
   */
  static int
  vacl_set_acl(struct vnode *vp, acl_type_t type, struct acl *aclp)
  {
  	struct thread *td = curthread;
  	struct acl inkernacl;
  	struct ucred *ucred;
  	int error;
  
  	error = copyin(aclp, &inkernacl, sizeof(struct acl));
  	if (error)
  		return(error);
  	ucred = td->td_ucred;
  
  	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
  	error = VOP_SETACL(vp, type, &inkernacl, ucred);
  	vn_unlock(vp);
  	return(error);
  }
  
  /*
   * Given a vnode, get its ACL.
   */
  static int
  vacl_get_acl(struct vnode *vp, acl_type_t type, struct acl *aclp)
  {
  	struct thread *td = curthread;
  	struct acl inkernelacl;
  	struct ucred *ucred;
  	int error;
  
  	ucred = td->td_ucred;
  	error = VOP_GETACL(vp, type, &inkernelacl, ucred);
  	if (error == 0)
  		error = copyout(&inkernelacl, aclp, sizeof(struct acl));
  	return (error);
  }
  
  /*
   * Given a vnode, delete its ACL.
   */
  static int
  vacl_delete(struct vnode *vp, acl_type_t type)
  {
  	struct thread *td = curthread;
  	struct ucred *ucred;
  	int error;
  
  	ucred = td->td_ucred;
  	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
  	error = VOP_SETACL(vp, ACL_TYPE_DEFAULT, 0, ucred);
  	vn_unlock(vp);
  	return (error);
  }
  
  /*
   * Given a vnode, check whether an ACL is appropriate for it
   */
  static int
  vacl_aclcheck(struct vnode *vp, acl_type_t type, struct acl *aclp)
  {
  	struct thread *td = curthread;
  	struct ucred *ucred;
  	struct acl inkernelacl;
  	int error;
  
  	ucred = td->td_ucred;
  	error = copyin(aclp, &inkernelacl, sizeof(struct acl));
  	if (error)
  		return(error);
  	error = VOP_ACLCHECK(vp, type, &inkernelacl, ucred);
  	return (error);
  }
  
  /*
   * syscalls -- convert the path/fd to a vnode, and call vacl_whatever.
   * Don't need to lock, as the vacl_ code will get/release any locks
   * required.
   */
  
  /*
   * Given a file path, get an ACL for it
   */
  int
  sys___acl_get_file(struct __acl_get_file_args *uap)
  {
  	struct nlookupdata nd;
  	struct vnode *vp;
  	int error;
  
  	vp = NULL;
  	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
  	if (error == 0)
  		error = nlookup(&nd);
  	if (error == 0)
  		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
  	nlookup_done(&nd);
  	if (error == 0) {
  		error = vacl_get_acl(vp, uap->type, uap->aclp);
  		vrele(vp);
  	}
  	return (error);
  }
  
  /*
   * Given a file path, set an ACL for it
   */
  int
  sys___acl_set_file(struct __acl_set_file_args *uap)
  {
  	struct nlookupdata nd;
  	struct vnode *vp;
  	int error;
  
  	vp = NULL;
  	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
  	if (error == 0)
  		error = nlookup(&nd);
  	if (error == 0)
  		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
  	nlookup_done(&nd);
  	if (error == 0) {
  		error = vacl_set_acl(vp, uap->type, uap->aclp);
  		vrele(vp);
  	}
  	return (error);
  }
  
  /*
   * Given a file descriptor, get an ACL for it
   */
  int
  sys___acl_get_fd(struct __acl_get_fd_args *uap)
  {
  	struct thread *td = curthread;
  	struct file *fp;
  	int error;
  
  	KKASSERT(td->td_proc);
  	if ((error = holdvnode(td->td_proc->p_fd, uap->filedes, &fp)) != 0)
  		return(error);
  	error = vacl_get_acl((struct vnode *)fp->f_data, uap->type, uap->aclp);
  	fdrop(fp);
  
  	return (error);
  }
  
  /*
   * Given a file descriptor, set an ACL for it
   */
  int
  sys___acl_set_fd(struct __acl_set_fd_args *uap)
  {
  	struct thread *td = curthread;
  	struct file *fp;
  	int error;
  
  	KKASSERT(td->td_proc);
  	if ((error = holdvnode(td->td_proc->p_fd, uap->filedes, &fp)) != 0)
  		return(error);
  	error = vacl_set_acl((struct vnode *)fp->f_data, uap->type, uap->aclp);
  	fdrop(fp);
  	return (error);
  }
  
  /*
   * Given a file path, delete an ACL from it.
   */
  int
  sys___acl_delete_file(struct __acl_delete_file_args *uap)
  {
  	struct nlookupdata nd;
  	struct vnode *vp;
  	int error;
  
  	vp = NULL;
  	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
  	if (error == 0)
  		error = nlookup(&nd);
  	if (error == 0)
  		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
  	nlookup_done(&nd);
  
  	if (error == 0) {
  		error = vacl_delete(vp, uap->type);
  		vrele(vp);
  	}
  	return (error);
  }
  
  /*
   * Given a file path, delete an ACL from it.
   */
  int
  sys___acl_delete_fd(struct __acl_delete_fd_args *uap)
  {
  	struct thread *td = curthread;
  	struct file *fp;
  	int error;
  
  	KKASSERT(td->td_proc);
  	if ((error = holdvnode(td->td_proc->p_fd, uap->filedes, &fp)) != 0)
  		return(error);
  	error = vacl_delete((struct vnode *)fp->f_data, uap->type);
  	fdrop(fp);
  	return (error);
  }
  
  /*
   * Given a file path, check an ACL for it
   */
  int
  sys___acl_aclcheck_file(struct __acl_aclcheck_file_args *uap)
  {
  	struct nlookupdata nd;
  	struct vnode *vp;
  	int error;
  
  	vp = NULL;
  	error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
  	if (error == 0)
  		error = nlookup(&nd);
  	if (error == 0)
  		error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
  	nlookup_done(&nd);
  
  	if (error == 0) {
  		error = vacl_aclcheck(vp, uap->type, uap->aclp);
  		vrele(vp);
  	}
  	return (error);
  }
  
  /*
   * Given a file descriptor, check an ACL for it
   */
  int
  sys___acl_aclcheck_fd(struct __acl_aclcheck_fd_args *uap)
  {
  	struct thread *td = curthread;
  	struct file *fp;
  	int error;
  
  	KKASSERT(td->td_proc);
  	if ((error = holdvnode(td->td_proc->p_fd, uap->filedes, &fp)) != 0)
  		return(error);
  	error = vacl_aclcheck((struct vnode *)fp->f_data, uap->type, uap->aclp);
  	fdrop(fp);
  	return (error);
  }
  
  