Logo Search packages:      
Sourcecode: ufsutils version File versions  Download package

ufs_extattr.c

/*-
 * Copyright (c) 1999-2002 Robert N. M. Watson
 * Copyright (c) 2002-2003 Networks Associates Technology, Inc.
 * All rights reserved.
 *
 * This software was developed by Robert Watson for the TrustedBSD Project.
 *
 * This software was developed for the FreeBSD Project in part by Network
 * Associates Laboratories, the Security Research Division of Network
 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
 * as part of the DARPA CHATS research program.
 *
 * 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.
 *
 */

/*
 * Support for filesystem extended attribute: UFS-specific support functions.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/ufs/ufs/ufs_extattr.c,v 1.86 2007/06/01 14:33:11 kib Exp $");

#include "opt_ufs.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/namei.h>
#include <sys/malloc.h>
#include <sys/fcntl.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/lock.h>
#include <sys/dirent.h>
#include <sys/extattr.h>
#include <sys/sysctl.h>

#include <vm/uma.h>

#include <ufs/ufs/dir.h>
#include <ufs/ufs/extattr.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufs_extern.h>

#ifdef UFS_EXTATTR

static MALLOC_DEFINE(M_UFS_EXTATTR, "ufs_extattr", "ufs extended attribute");

static int ufs_extattr_sync = 0;
SYSCTL_INT(_debug, OID_AUTO, ufs_extattr_sync, CTLFLAG_RW, &ufs_extattr_sync,
    0, "");

static int  ufs_extattr_valid_attrname(int attrnamespace,
                const char *attrname);
static int  ufs_extattr_enable_with_open(struct ufsmount *ump,
                struct vnode *vp, int attrnamespace, const char *attrname,
                struct thread *td);
static int  ufs_extattr_enable(struct ufsmount *ump, int attrnamespace,
                const char *attrname, struct vnode *backing_vnode,
                struct thread *td);
static int  ufs_extattr_disable(struct ufsmount *ump, int attrnamespace,
                const char *attrname, struct thread *td);
static int  ufs_extattr_get(struct vnode *vp, int attrnamespace,
                const char *name, struct uio *uio, size_t *size,
                struct ucred *cred, struct thread *td);
static int  ufs_extattr_set(struct vnode *vp, int attrnamespace,
                const char *name, struct uio *uio, struct ucred *cred,
                struct thread *td);
static int  ufs_extattr_rm(struct vnode *vp, int attrnamespace,
                const char *name, struct ucred *cred, struct thread *td);

/*
 * Per-FS attribute lock protecting attribute operations.
 * XXX Right now there is a lot of lock contention due to having a single
 * lock per-FS; really, this should be far more fine-grained.
 */
static void
ufs_extattr_uepm_lock(struct ufsmount *ump, struct thread *td)
{

      /* Ideally, LK_CANRECURSE would not be used, here. */
      lockmgr(&ump->um_extattr.uepm_lock, LK_EXCLUSIVE | LK_RETRY |
          LK_CANRECURSE, 0, td);
}

static void
ufs_extattr_uepm_unlock(struct ufsmount *ump, struct thread *td)
{

      lockmgr(&ump->um_extattr.uepm_lock, LK_RELEASE, 0, td);
}

/*-
 * Determine whether the name passed is a valid name for an actual
 * attribute.
 *
 * Invalid currently consists of:
 *     NULL pointer for attrname
 *     zero-length attrname (used to retrieve application attribute list)
 */
static int
ufs_extattr_valid_attrname(int attrnamespace, const char *attrname)
{

      if (attrname == NULL)
            return (0);
      if (strlen(attrname) == 0)
            return (0);
      return (1);
}

/*
 * Locate an attribute given a name and mountpoint.
 * Must be holding uepm lock for the mount point.
 */
static struct ufs_extattr_list_entry *
ufs_extattr_find_attr(struct ufsmount *ump, int attrnamespace,
    const char *attrname)
{
      struct ufs_extattr_list_entry *search_attribute;

      for (search_attribute = LIST_FIRST(&ump->um_extattr.uepm_list);
          search_attribute != NULL;
          search_attribute = LIST_NEXT(search_attribute, uele_entries)) {
            if (!(strncmp(attrname, search_attribute->uele_attrname,
                UFS_EXTATTR_MAXEXTATTRNAME)) &&
                (attrnamespace == search_attribute->uele_attrnamespace)) {
                  return (search_attribute);
            }
      }

      return (0);
}

/*
 * Initialize per-FS structures supporting extended attributes.  Do not
 * start extended attributes yet.
 */
void
ufs_extattr_uepm_init(struct ufs_extattr_per_mount *uepm)
{

      uepm->uepm_flags = 0;

      LIST_INIT(&uepm->uepm_list);
      /* XXX is PVFS right, here? */
      lockinit(&uepm->uepm_lock, PVFS, "extattr", 0, 0);
      uepm->uepm_flags |= UFS_EXTATTR_UEPM_INITIALIZED;
}

/*
 * Destroy per-FS structures supporting extended attributes.  Assumes
 * that EAs have already been stopped, and will panic if not.
 */
void
ufs_extattr_uepm_destroy(struct ufs_extattr_per_mount *uepm)
{

      if (!(uepm->uepm_flags & UFS_EXTATTR_UEPM_INITIALIZED))
            panic("ufs_extattr_uepm_destroy: not initialized");

      if ((uepm->uepm_flags & UFS_EXTATTR_UEPM_STARTED))
            panic("ufs_extattr_uepm_destroy: called while still started");

      /*
       * It's not clear that either order for the next two lines is
       * ideal, and it should never be a problem if this is only called
       * during unmount, and with vfs_busy().
       */
      uepm->uepm_flags &= ~UFS_EXTATTR_UEPM_INITIALIZED;
      lockdestroy(&uepm->uepm_lock);
}

/*
 * Start extended attribute support on an FS.
 */
int
ufs_extattr_start(struct mount *mp, struct thread *td)
{
      struct ufsmount *ump;
      int error = 0;

      ump = VFSTOUFS(mp);

      ufs_extattr_uepm_lock(ump, td);

      if (!(ump->um_extattr.uepm_flags & UFS_EXTATTR_UEPM_INITIALIZED)) {
            error = EOPNOTSUPP;
            goto unlock;
      }
      if (ump->um_extattr.uepm_flags & UFS_EXTATTR_UEPM_STARTED) {
            error = EBUSY;
            goto unlock;
      }

      ump->um_extattr.uepm_flags |= UFS_EXTATTR_UEPM_STARTED;

      ump->um_extattr.uepm_ucred = crhold(td->td_ucred);

unlock:
      ufs_extattr_uepm_unlock(ump, td);

      return (error);
}

#ifdef UFS_EXTATTR_AUTOSTART
/*
 * Helper routine: given a locked parent directory and filename, return
 * the locked vnode of the inode associated with the name.  Will not
 * follow symlinks, may return any type of vnode.  Lock on parent will
 * be released even in the event of a failure.  In the event that the
 * target is the parent (i.e., "."), there will be two references and
 * one lock, requiring the caller to possibly special-case.
 */
#define     UE_GETDIR_LOCKPARENT    1
#define     UE_GETDIR_LOCKPARENT_DONT     2
static int
ufs_extattr_lookup(struct vnode *start_dvp, int lockparent, char *dirname,
    struct vnode **vp, struct thread *td)
{
      struct vop_cachedlookup_args vargs;
      struct componentname cnp;
      struct vnode *target_vp;
      int error;

      bzero(&cnp, sizeof(cnp));
      cnp.cn_nameiop = LOOKUP;
      cnp.cn_flags = ISLASTCN;
      if (lockparent == UE_GETDIR_LOCKPARENT)
            cnp.cn_flags |= LOCKPARENT;
      cnp.cn_lkflags = LK_EXCLUSIVE;
      cnp.cn_thread = td;
      cnp.cn_cred = td->td_ucred;
      cnp.cn_pnbuf = uma_zalloc(namei_zone, M_WAITOK);
      cnp.cn_nameptr = cnp.cn_pnbuf;
      error = copystr(dirname, cnp.cn_pnbuf, MAXPATHLEN,
          (size_t *) &cnp.cn_namelen);
      if (error) {
            if (lockparent == UE_GETDIR_LOCKPARENT_DONT) {
                  VOP_UNLOCK(start_dvp, 0, td);
            }
            uma_zfree(namei_zone, cnp.cn_pnbuf);
            printf("ufs_extattr_lookup: copystr failed\n");
            return (error);
      }
      cnp.cn_namelen--; /* trim nul termination */
      vargs.a_gen.a_desc = NULL;
      vargs.a_dvp = start_dvp;
      vargs.a_vpp = &target_vp;
      vargs.a_cnp = &cnp;
      error = ufs_lookup(&vargs);
      uma_zfree(namei_zone, cnp.cn_pnbuf);
      if (error) {
            /*
             * Error condition, may have to release the lock on the parent
             * if ufs_lookup() didn't.
             */
            if (lockparent == UE_GETDIR_LOCKPARENT_DONT)
                  VOP_UNLOCK(start_dvp, 0, td);

            /*
             * Check that ufs_lookup() didn't release the lock when we
             * didn't want it to.
             */
            if (lockparent == UE_GETDIR_LOCKPARENT)
                  ASSERT_VOP_LOCKED(start_dvp, "ufs_extattr_lookup");

            return (error);
      }
/*
      if (target_vp == start_dvp)
            panic("ufs_extattr_lookup: target_vp == start_dvp");
*/

      if (target_vp != start_dvp && lockparent == UE_GETDIR_LOCKPARENT_DONT)
            VOP_UNLOCK(start_dvp, 0, td);

      if (lockparent == UE_GETDIR_LOCKPARENT)
            ASSERT_VOP_LOCKED(start_dvp, "ufs_extattr_lookup");

      /* printf("ufs_extattr_lookup: success\n"); */
      *vp = target_vp;
      return (0);
}
#endif /* !UFS_EXTATTR_AUTOSTART */

/*
 * Enable an EA using the passed filesystem, backing vnode, attribute name,
 * namespace, and proc.  Will perform a VOP_OPEN() on the vp, so expects vp
 * to be locked when passed in.  The vnode will be returned unlocked,
 * regardless of success/failure of the function.  As a result, the caller
 * will always need to vrele(), but not vput().
 */
static int
ufs_extattr_enable_with_open(struct ufsmount *ump, struct vnode *vp,
    int attrnamespace, const char *attrname, struct thread *td)
{
      int error;

      error = VOP_OPEN(vp, FREAD|FWRITE, td->td_ucred, td, NULL);
      if (error) {
            printf("ufs_extattr_enable_with_open.VOP_OPEN(): failed "
                "with %d\n", error);
            VOP_UNLOCK(vp, 0, td);
            return (error);
      }

      vp->v_writecount++;

      vref(vp);

      VOP_UNLOCK(vp, 0, td);

      error = ufs_extattr_enable(ump, attrnamespace, attrname, vp, td);
      if (error != 0)
            vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
      return (error);
}

#ifdef UFS_EXTATTR_AUTOSTART
/*
 * Given a locked directory vnode, iterate over the names in the directory
 * and use ufs_extattr_lookup() to retrieve locked vnodes of potential
 * attribute files.  Then invoke ufs_extattr_enable_with_open() on each
 * to attempt to start the attribute.  Leaves the directory locked on
 * exit.
 */
static int
ufs_extattr_iterate_directory(struct ufsmount *ump, struct vnode *dvp,
    int attrnamespace, struct thread *td)
{
      struct vop_readdir_args vargs;
      struct dirent *dp, *edp;
      struct vnode *attr_vp;
      struct uio auio;
      struct iovec aiov;
      char *dirbuf;
      int error, eofflag = 0;

      if (dvp->v_type != VDIR)
            return (ENOTDIR);

      MALLOC(dirbuf, char *, DIRBLKSIZ, M_TEMP, M_WAITOK);

      auio.uio_iov = &aiov;
      auio.uio_iovcnt = 1;
      auio.uio_rw = UIO_READ;
      auio.uio_segflg = UIO_SYSSPACE;
      auio.uio_td = td;
      auio.uio_offset = 0;

      vargs.a_gen.a_desc = NULL;
      vargs.a_vp = dvp;
      vargs.a_uio = &auio;
      vargs.a_cred = td->td_ucred;
      vargs.a_eofflag = &eofflag;
      vargs.a_ncookies = NULL;
      vargs.a_cookies = NULL;

      while (!eofflag) {
            auio.uio_resid = DIRBLKSIZ;
            aiov.iov_base = dirbuf;
            aiov.iov_len = DIRBLKSIZ;
            error = ufs_readdir(&vargs);
            if (error) {
                  printf("ufs_extattr_iterate_directory: ufs_readdir "
                      "%d\n", error);
                  return (error);
            }

            /*
             * XXXRW: While in UFS, we always get DIRBLKSIZ returns from
             * the directory code on success, on other file systems this
             * may not be the case.  For portability, we should check the
             * read length on return from ufs_readdir().
             */
            edp = (struct dirent *)&dirbuf[DIRBLKSIZ];
            for (dp = (struct dirent *)dirbuf; dp < edp; ) {
#if (BYTE_ORDER == LITTLE_ENDIAN)
                  dp->d_type = dp->d_namlen;
                  dp->d_namlen = 0;
#else
                  dp->d_type = 0;
#endif
                  if (dp->d_reclen == 0)
                        break;
                  error = ufs_extattr_lookup(dvp, UE_GETDIR_LOCKPARENT,
                      dp->d_name, &attr_vp, td);
                  if (error) {
                        printf("ufs_extattr_iterate_directory: lookup "
                            "%s %d\n", dp->d_name, error);
                  } else if (attr_vp == dvp) {
                        vrele(attr_vp);
                  } else if (attr_vp->v_type != VREG) {
                        vput(attr_vp);
                  } else {
                        error = ufs_extattr_enable_with_open(ump,
                            attr_vp, attrnamespace, dp->d_name, td);
                        vrele(attr_vp);
                        if (error) {
                              printf("ufs_extattr_iterate_directory: "
                                  "enable %s %d\n", dp->d_name,
                                  error);
                        } else if (bootverbose) {
                              printf("UFS autostarted EA %s\n",
                                  dp->d_name);
                        }
                  }
                  dp = (struct dirent *) ((char *)dp + dp->d_reclen);
                  if (dp >= edp)
                        break;
            }
      }
      FREE(dirbuf, M_TEMP);
      
      return (0);
}

/*
 * Auto-start of extended attributes, to be executed (optionally) at
 * mount-time.
 */
int
ufs_extattr_autostart(struct mount *mp, struct thread *td)
{
      struct vnode *rvp, *attr_dvp, *attr_system_dvp, *attr_user_dvp;
      int error;

      /*
       * Does UFS_EXTATTR_FSROOTSUBDIR exist off the filesystem root?
       * If so, automatically start EA's.
       */
      error = VFS_ROOT(mp, LK_EXCLUSIVE, &rvp, td);
      if (error) {
            printf("ufs_extattr_autostart.VFS_ROOT() returned %d\n",
                error);
            return (error);
      }

      error = ufs_extattr_lookup(rvp, UE_GETDIR_LOCKPARENT_DONT,
          UFS_EXTATTR_FSROOTSUBDIR, &attr_dvp, td);
      if (error) {
            /* rvp ref'd but now unlocked */
            vrele(rvp);
            return (error);
      }
      if (rvp == attr_dvp) {
            /* Should never happen. */
            vput(rvp);
            vrele(attr_dvp);
            return (EINVAL);
      }
      vrele(rvp);

      if (attr_dvp->v_type != VDIR) {
            printf("ufs_extattr_autostart: %s != VDIR\n",
                UFS_EXTATTR_FSROOTSUBDIR);
            goto return_vput_attr_dvp;
      }

      error = ufs_extattr_start(mp, td);
      if (error) {
            printf("ufs_extattr_autostart: ufs_extattr_start failed (%d)\n",
                error);
            goto return_vput_attr_dvp;
      }

      /*
       * Look for two subdirectories: UFS_EXTATTR_SUBDIR_SYSTEM,
       * UFS_EXTATTR_SUBDIR_USER.  For each, iterate over the sub-directory,
       * and start with appropriate type.  Failures in either don't
       * result in an over-all failure.  attr_dvp is left locked to
       * be cleaned up on exit.
       */
      error = ufs_extattr_lookup(attr_dvp, UE_GETDIR_LOCKPARENT,
          UFS_EXTATTR_SUBDIR_SYSTEM, &attr_system_dvp, td);
      if (!error) {
            error = ufs_extattr_iterate_directory(VFSTOUFS(mp),
                attr_system_dvp, EXTATTR_NAMESPACE_SYSTEM, td);
            if (error)
                  printf("ufs_extattr_iterate_directory returned %d\n",
                      error);
            vput(attr_system_dvp);
      }

      error = ufs_extattr_lookup(attr_dvp, UE_GETDIR_LOCKPARENT,
          UFS_EXTATTR_SUBDIR_USER, &attr_user_dvp, td);
      if (!error) {
            error = ufs_extattr_iterate_directory(VFSTOUFS(mp),
                attr_user_dvp, EXTATTR_NAMESPACE_USER, td);
            if (error)
                  printf("ufs_extattr_iterate_directory returned %d\n",
                      error);
            vput(attr_user_dvp);
      }

      /* Mask startup failures in sub-directories. */
      error = 0;

return_vput_attr_dvp:
      vput(attr_dvp);

      return (error);
}
#endif /* !UFS_EXTATTR_AUTOSTART */

/*
 * Stop extended attribute support on an FS.
 */
int
ufs_extattr_stop(struct mount *mp, struct thread *td)
{
      struct ufs_extattr_list_entry *uele;
      struct ufsmount *ump = VFSTOUFS(mp);
      int error = 0;

      ufs_extattr_uepm_lock(ump, td);

      if (!(ump->um_extattr.uepm_flags & UFS_EXTATTR_UEPM_STARTED)) {
            error = EOPNOTSUPP;
            goto unlock;
      }

      while ((uele = LIST_FIRST(&ump->um_extattr.uepm_list)) != NULL) {
            ufs_extattr_disable(ump, uele->uele_attrnamespace,
                uele->uele_attrname, td);
      }

      ump->um_extattr.uepm_flags &= ~UFS_EXTATTR_UEPM_STARTED;

      crfree(ump->um_extattr.uepm_ucred);
      ump->um_extattr.uepm_ucred = NULL;

unlock:
      ufs_extattr_uepm_unlock(ump, td);

      return (error);
}

/*
 * Enable a named attribute on the specified filesystem; provide an
 * unlocked backing vnode to hold the attribute data.
 */
static int
ufs_extattr_enable(struct ufsmount *ump, int attrnamespace,
    const char *attrname, struct vnode *backing_vnode, struct thread *td)
{
      struct ufs_extattr_list_entry *attribute;
      struct iovec aiov;
      struct uio auio;
      int error = 0;

      if (!ufs_extattr_valid_attrname(attrnamespace, attrname))
            return (EINVAL);
      if (backing_vnode->v_type != VREG)
            return (EINVAL);

      MALLOC(attribute, struct ufs_extattr_list_entry *,
          sizeof(struct ufs_extattr_list_entry), M_UFS_EXTATTR, M_WAITOK);
      if (attribute == NULL)
            return (ENOMEM);

      if (!(ump->um_extattr.uepm_flags & UFS_EXTATTR_UEPM_STARTED)) {
            error = EOPNOTSUPP;
            goto free_exit;
      }

      if (ufs_extattr_find_attr(ump, attrnamespace, attrname)) {
            error = EEXIST;
            goto free_exit;
      }

      strncpy(attribute->uele_attrname, attrname,
          UFS_EXTATTR_MAXEXTATTRNAME);
      attribute->uele_attrnamespace = attrnamespace;
      bzero(&attribute->uele_fileheader,
          sizeof(struct ufs_extattr_fileheader));
      
      attribute->uele_backing_vnode = backing_vnode;

      auio.uio_iov = &aiov;
      auio.uio_iovcnt = 1;
      aiov.iov_base = (caddr_t) &attribute->uele_fileheader;
      aiov.iov_len = sizeof(struct ufs_extattr_fileheader);
      auio.uio_resid = sizeof(struct ufs_extattr_fileheader);
      auio.uio_offset = (off_t) 0;
      auio.uio_segflg = UIO_SYSSPACE;
      auio.uio_rw = UIO_READ;
      auio.uio_td = td;

      vn_lock(backing_vnode, LK_SHARED | LK_RETRY, td);
      error = VOP_READ(backing_vnode, &auio, IO_NODELOCKED,
          ump->um_extattr.uepm_ucred);

      if (error)
            goto unlock_free_exit;

      if (auio.uio_resid != 0) {
            printf("ufs_extattr_enable: malformed attribute header\n");
            error = EINVAL;
            goto unlock_free_exit;
      }

      if (attribute->uele_fileheader.uef_magic != UFS_EXTATTR_MAGIC) {
            printf("ufs_extattr_enable: invalid attribute header magic\n");
            error = EINVAL;
            goto unlock_free_exit;
      }

      if (attribute->uele_fileheader.uef_version != UFS_EXTATTR_VERSION) {
            printf("ufs_extattr_enable: incorrect attribute header "
                "version\n");
            error = EINVAL;
            goto unlock_free_exit;
      }

      ASSERT_VOP_LOCKED(backing_vnode, "ufs_extattr_enable");
      LIST_INSERT_HEAD(&ump->um_extattr.uepm_list, attribute,
          uele_entries);

      VOP_UNLOCK(backing_vnode, 0, td);
      return (0);

unlock_free_exit:
      VOP_UNLOCK(backing_vnode, 0, td);

free_exit:
      FREE(attribute, M_UFS_EXTATTR);
      return (error);
}

/*
 * Disable extended attribute support on an FS.
 */
static int
ufs_extattr_disable(struct ufsmount *ump, int attrnamespace,
    const char *attrname, struct thread *td)
{
      struct ufs_extattr_list_entry *uele;
      int error = 0;

      if (!ufs_extattr_valid_attrname(attrnamespace, attrname))
            return (EINVAL);

      uele = ufs_extattr_find_attr(ump, attrnamespace, attrname);
      if (!uele)
            return (ENOATTR);

      LIST_REMOVE(uele, uele_entries);

      vn_lock(uele->uele_backing_vnode, LK_SHARED | LK_RETRY,
          td);
      ASSERT_VOP_LOCKED(uele->uele_backing_vnode, "ufs_extattr_disable");
      VOP_UNLOCK(uele->uele_backing_vnode, 0, td);
      error = vn_close(uele->uele_backing_vnode, FREAD|FWRITE,
          td->td_ucred, td);

      FREE(uele, M_UFS_EXTATTR);

      return (error);
}

/*
 * VFS call to manage extended attributes in UFS.  If filename_vp is
 * non-NULL, it must be passed in locked, and regardless of errors in
 * processing, will be unlocked.
 */
int
ufs_extattrctl(struct mount *mp, int cmd, struct vnode *filename_vp,
    int attrnamespace, const char *attrname, struct thread *td)
{
      struct ufsmount *ump = VFSTOUFS(mp);
      int error;

      /*
       * Processes with privilege, but in jail, are not allowed to
       * configure extended attributes.
       */
      error = priv_check(td, PRIV_UFS_EXTATTRCTL);
      if (error) {
            if (filename_vp != NULL)
                  VOP_UNLOCK(filename_vp, 0, td);
            return (error);
      }

      switch(cmd) {
      case UFS_EXTATTR_CMD_START:
            if (filename_vp != NULL) {
                  VOP_UNLOCK(filename_vp, 0, td);
                  return (EINVAL);
            }
            if (attrname != NULL)
                  return (EINVAL);

            error = ufs_extattr_start(mp, td);

            return (error);
            
      case UFS_EXTATTR_CMD_STOP:
            if (filename_vp != NULL) {
                  VOP_UNLOCK(filename_vp, 0, td);
                  return (EINVAL);
            }
            if (attrname != NULL)
                  return (EINVAL);

            error = ufs_extattr_stop(mp, td);

            return (error);

      case UFS_EXTATTR_CMD_ENABLE:

            if (filename_vp == NULL)
                  return (EINVAL);
            if (attrname == NULL) {
                  VOP_UNLOCK(filename_vp, 0, td);
                  return (EINVAL);
            }

            /*
             * ufs_extattr_enable_with_open() will always unlock the
             * vnode, regardless of failure.
             */
            ufs_extattr_uepm_lock(ump, td);
            error = ufs_extattr_enable_with_open(ump, filename_vp,
                attrnamespace, attrname, td);
            ufs_extattr_uepm_unlock(ump, td);

            return (error);

      case UFS_EXTATTR_CMD_DISABLE:

            if (filename_vp != NULL) {
                  VOP_UNLOCK(filename_vp, 0, td);
                  return (EINVAL);
            }
            if (attrname == NULL)
                  return (EINVAL);

            ufs_extattr_uepm_lock(ump, td);
            error = ufs_extattr_disable(ump, attrnamespace, attrname,
                td);
            ufs_extattr_uepm_unlock(ump, td);

            return (error);

      default:
            return (EINVAL);
      }
}

/*
 * Vnode operating to retrieve a named extended attribute.
 */
int
ufs_getextattr(struct vop_getextattr_args *ap)
/*
vop_getextattr {
      IN struct vnode *a_vp;
      IN int a_attrnamespace;
      IN const char *a_name;
      INOUT struct uio *a_uio;
      OUT size_t *a_size;
      IN struct ucred *a_cred;
      IN struct thread *a_td;
};
*/
{
      struct mount *mp = ap->a_vp->v_mount;
      struct ufsmount *ump = VFSTOUFS(mp);
      int error;

      ufs_extattr_uepm_lock(ump, ap->a_td);

      error = ufs_extattr_get(ap->a_vp, ap->a_attrnamespace, ap->a_name,
          ap->a_uio, ap->a_size, ap->a_cred, ap->a_td);

      ufs_extattr_uepm_unlock(ump, ap->a_td);

      return (error);
}

/*
 * Real work associated with retrieving a named attribute--assumes that
 * the attribute lock has already been grabbed.
 */
static int
ufs_extattr_get(struct vnode *vp, int attrnamespace, const char *name,
    struct uio *uio, size_t *size, struct ucred *cred, struct thread *td)
{
      struct ufs_extattr_list_entry *attribute;
      struct ufs_extattr_header ueh;
      struct iovec local_aiov;
      struct uio local_aio;
      struct mount *mp = vp->v_mount;
      struct ufsmount *ump = VFSTOUFS(mp);
      struct inode *ip = VTOI(vp);
      off_t base_offset;
      size_t len, old_len;
      int error = 0;

      if (!(ump->um_extattr.uepm_flags & UFS_EXTATTR_UEPM_STARTED))
            return (EOPNOTSUPP);

      if (strlen(name) == 0)
            return (EINVAL);

      error = extattr_check_cred(vp, attrnamespace, cred, td, IREAD);
      if (error)
            return (error);

      attribute = ufs_extattr_find_attr(ump, attrnamespace, name);
      if (!attribute)
            return (ENOATTR);

      /*
       * Allow only offsets of zero to encourage the read/replace
       * extended attribute semantic.  Otherwise we can't guarantee
       * atomicity, as we don't provide locks for extended attributes.
       */
      if (uio != NULL && uio->uio_offset != 0)
            return (ENXIO);

      /*
       * Find base offset of header in file based on file header size, and
       * data header size + maximum data size, indexed by inode number.
       */
      base_offset = sizeof(struct ufs_extattr_fileheader) +
          ip->i_number * (sizeof(struct ufs_extattr_header) +
          attribute->uele_fileheader.uef_size);

      /*
       * Read in the data header to see if the data is defined, and if so
       * how much.
       */
      bzero(&ueh, sizeof(struct ufs_extattr_header));
      local_aiov.iov_base = (caddr_t) &ueh;
      local_aiov.iov_len = sizeof(struct ufs_extattr_header);
      local_aio.uio_iov = &local_aiov;
      local_aio.uio_iovcnt = 1;
      local_aio.uio_rw = UIO_READ;
      local_aio.uio_segflg = UIO_SYSSPACE;
      local_aio.uio_td = td;
      local_aio.uio_offset = base_offset;
      local_aio.uio_resid = sizeof(struct ufs_extattr_header);
      
      /*
       * Acquire locks.
       *
       * Don't need to get a lock on the backing file if the getattr is
       * being applied to the backing file, as the lock is already held.
       */
      if (attribute->uele_backing_vnode != vp)
            vn_lock(attribute->uele_backing_vnode, LK_SHARED |
                LK_RETRY, td);

      error = VOP_READ(attribute->uele_backing_vnode, &local_aio,
          IO_NODELOCKED, ump->um_extattr.uepm_ucred);
      if (error)
            goto vopunlock_exit;

      /* Defined? */
      if ((ueh.ueh_flags & UFS_EXTATTR_ATTR_FLAG_INUSE) == 0) {
            error = ENOATTR;
            goto vopunlock_exit;
      }

      /* Valid for the current inode generation? */
      if (ueh.ueh_i_gen != ip->i_gen) {
            /*
             * The inode itself has a different generation number
             * than the attribute data.  For now, the best solution
             * is to coerce this to undefined, and let it get cleaned
             * up by the next write or extattrctl clean.
             */
            printf("ufs_extattr_get (%s): inode number inconsistency (%d, %jd)\n",
                mp->mnt_stat.f_mntonname, ueh.ueh_i_gen, (intmax_t)ip->i_gen);
            error = ENOATTR;
            goto vopunlock_exit;
      }

      /* Local size consistency check. */
      if (ueh.ueh_len > attribute->uele_fileheader.uef_size) {
            error = ENXIO;
            goto vopunlock_exit;
      }

      /* Return full data size if caller requested it. */
      if (size != NULL)
            *size = ueh.ueh_len;

      /* Return data if the caller requested it. */
      if (uio != NULL) {
            /* Allow for offset into the attribute data. */
            uio->uio_offset = base_offset + sizeof(struct
                ufs_extattr_header);

            /*
             * Figure out maximum to transfer -- use buffer size and
             * local data limit.
             */
            len = MIN(uio->uio_resid, ueh.ueh_len);
            old_len = uio->uio_resid;
            uio->uio_resid = len;

            error = VOP_READ(attribute->uele_backing_vnode, uio,
                IO_NODELOCKED, ump->um_extattr.uepm_ucred);
            if (error)
                  goto vopunlock_exit;

            uio->uio_resid = old_len - (len - uio->uio_resid);
      }

vopunlock_exit:

      if (uio != NULL)
            uio->uio_offset = 0;

      if (attribute->uele_backing_vnode != vp)
            VOP_UNLOCK(attribute->uele_backing_vnode, 0, td);

      return (error);
}

/*
 * Vnode operation to remove a named attribute.
 */
int
ufs_deleteextattr(struct vop_deleteextattr_args *ap)
/*
vop_deleteextattr {
      IN struct vnode *a_vp;
      IN int a_attrnamespace;
      IN const char *a_name;
      IN struct ucred *a_cred;
      IN struct thread *a_td;
};
*/
{
      struct mount *mp = ap->a_vp->v_mount;
      struct ufsmount *ump = VFSTOUFS(mp); 
      int error;

      ufs_extattr_uepm_lock(ump, ap->a_td);

      error = ufs_extattr_rm(ap->a_vp, ap->a_attrnamespace, ap->a_name,
          ap->a_cred, ap->a_td);


      ufs_extattr_uepm_unlock(ump, ap->a_td);

      return (error);
}

/*
 * Vnode operation to set a named attribute.
 */
int
ufs_setextattr(struct vop_setextattr_args *ap)
/*
vop_setextattr {
      IN struct vnode *a_vp;
      IN int a_attrnamespace;
      IN const char *a_name;
      INOUT struct uio *a_uio;
      IN struct ucred *a_cred;
      IN struct thread *a_td;
};
*/
{
      struct mount *mp = ap->a_vp->v_mount;
      struct ufsmount *ump = VFSTOUFS(mp); 
      int error;

      ufs_extattr_uepm_lock(ump, ap->a_td);

      /*
       * XXX: No longer a supported way to delete extended attributes.
       */
      if (ap->a_uio == NULL)
            return (EINVAL);

      error = ufs_extattr_set(ap->a_vp, ap->a_attrnamespace, ap->a_name,
          ap->a_uio, ap->a_cred, ap->a_td);

      ufs_extattr_uepm_unlock(ump, ap->a_td);

      return (error);
}

/*
 * Real work associated with setting a vnode's extended attributes;
 * assumes that the attribute lock has already been grabbed.
 */
static int
ufs_extattr_set(struct vnode *vp, int attrnamespace, const char *name,
    struct uio *uio, struct ucred *cred, struct thread *td)
{
      struct ufs_extattr_list_entry *attribute;
      struct ufs_extattr_header ueh;
      struct iovec local_aiov;
      struct uio local_aio;
      struct mount *mp = vp->v_mount;
      struct ufsmount *ump = VFSTOUFS(mp);
      struct inode *ip = VTOI(vp);
      off_t base_offset;
      int error = 0, ioflag;

      if (vp->v_mount->mnt_flag & MNT_RDONLY)
            return (EROFS);
      if (!(ump->um_extattr.uepm_flags & UFS_EXTATTR_UEPM_STARTED))
            return (EOPNOTSUPP);
      if (!ufs_extattr_valid_attrname(attrnamespace, name))
            return (EINVAL);

      error = extattr_check_cred(vp, attrnamespace, cred, td, IWRITE);
      if (error)
            return (error);

      attribute = ufs_extattr_find_attr(ump, attrnamespace, name);
      if (!attribute)
            return (ENOATTR);

      /*
       * Early rejection of invalid offsets/length.
       * Reject: any offset but 0 (replace)
       *     Any size greater than attribute size limit
       */
      if (uio->uio_offset != 0 ||
          uio->uio_resid > attribute->uele_fileheader.uef_size)
            return (ENXIO);

      /*
       * Find base offset of header in file based on file header size, and
       * data header size + maximum data size, indexed by inode number.
       */
      base_offset = sizeof(struct ufs_extattr_fileheader) +
          ip->i_number * (sizeof(struct ufs_extattr_header) +
          attribute->uele_fileheader.uef_size);

      /*
       * Write out a data header for the data.
       */
      ueh.ueh_len = uio->uio_resid;
      ueh.ueh_flags = UFS_EXTATTR_ATTR_FLAG_INUSE;
      ueh.ueh_i_gen = ip->i_gen;
      local_aiov.iov_base = (caddr_t) &ueh;
      local_aiov.iov_len = sizeof(struct ufs_extattr_header);
      local_aio.uio_iov = &local_aiov;
      local_aio.uio_iovcnt = 1;
      local_aio.uio_rw = UIO_WRITE;
      local_aio.uio_segflg = UIO_SYSSPACE;
      local_aio.uio_td = td;
      local_aio.uio_offset = base_offset;
      local_aio.uio_resid = sizeof(struct ufs_extattr_header);

      /*
       * Acquire locks.
       *
       * Don't need to get a lock on the backing file if the setattr is
       * being applied to the backing file, as the lock is already held.
       */
      if (attribute->uele_backing_vnode != vp)
            vn_lock(attribute->uele_backing_vnode, 
                LK_EXCLUSIVE | LK_RETRY, td);

      ioflag = IO_NODELOCKED;
      if (ufs_extattr_sync)
            ioflag |= IO_SYNC;
      error = VOP_WRITE(attribute->uele_backing_vnode, &local_aio, ioflag,
          ump->um_extattr.uepm_ucred);
      if (error)
            goto vopunlock_exit;

      if (local_aio.uio_resid != 0) {
            error = ENXIO;
            goto vopunlock_exit;
      }

      /*
       * Write out user data.
       */
      uio->uio_offset = base_offset + sizeof(struct ufs_extattr_header);

      ioflag = IO_NODELOCKED;
      if (ufs_extattr_sync)
            ioflag |= IO_SYNC;
      error = VOP_WRITE(attribute->uele_backing_vnode, uio, ioflag,
          ump->um_extattr.uepm_ucred);

vopunlock_exit:
      uio->uio_offset = 0;

      if (attribute->uele_backing_vnode != vp)
            VOP_UNLOCK(attribute->uele_backing_vnode, 0, td);

      return (error);
}

/*
 * Real work associated with removing an extended attribute from a vnode.
 * Assumes the attribute lock has already been grabbed.
 */
static int
ufs_extattr_rm(struct vnode *vp, int attrnamespace, const char *name,
    struct ucred *cred, struct thread *td)
{
      struct ufs_extattr_list_entry *attribute;
      struct ufs_extattr_header ueh;
      struct iovec local_aiov;
      struct uio local_aio;
      struct mount *mp = vp->v_mount;
      struct ufsmount *ump = VFSTOUFS(mp);
      struct inode *ip = VTOI(vp);
      off_t base_offset;
      int error = 0, ioflag;

      if (vp->v_mount->mnt_flag & MNT_RDONLY)  
            return (EROFS);
      if (!(ump->um_extattr.uepm_flags & UFS_EXTATTR_UEPM_STARTED))
            return (EOPNOTSUPP);
      if (!ufs_extattr_valid_attrname(attrnamespace, name))
            return (EINVAL);

      error = extattr_check_cred(vp, attrnamespace, cred, td, IWRITE);
      if (error)
            return (error);

      attribute = ufs_extattr_find_attr(ump, attrnamespace, name);
      if (!attribute)
            return (ENOATTR);

      /*
       * Find base offset of header in file based on file header size, and
       * data header size + maximum data size, indexed by inode number.
       */
      base_offset = sizeof(struct ufs_extattr_fileheader) +
          ip->i_number * (sizeof(struct ufs_extattr_header) +
          attribute->uele_fileheader.uef_size);

      /*
       * Check to see if currently defined.
       */
      bzero(&ueh, sizeof(struct ufs_extattr_header));

      local_aiov.iov_base = (caddr_t) &ueh;
      local_aiov.iov_len = sizeof(struct ufs_extattr_header);
      local_aio.uio_iov = &local_aiov;
      local_aio.uio_iovcnt = 1;
      local_aio.uio_rw = UIO_READ;
      local_aio.uio_segflg = UIO_SYSSPACE;
      local_aio.uio_td = td;
      local_aio.uio_offset = base_offset;
      local_aio.uio_resid = sizeof(struct ufs_extattr_header);

      /*
       * Don't need to get the lock on the backing vnode if the vnode we're
       * modifying is it, as we already hold the lock.
       */
      if (attribute->uele_backing_vnode != vp)
            vn_lock(attribute->uele_backing_vnode,
                LK_EXCLUSIVE | LK_RETRY, td);

      error = VOP_READ(attribute->uele_backing_vnode, &local_aio,
          IO_NODELOCKED, ump->um_extattr.uepm_ucred);
      if (error)
            goto vopunlock_exit;

      /* Defined? */
      if ((ueh.ueh_flags & UFS_EXTATTR_ATTR_FLAG_INUSE) == 0) {
            error = ENOATTR;
            goto vopunlock_exit;
      }

      /* Valid for the current inode generation? */
      if (ueh.ueh_i_gen != ip->i_gen) {
            /*
             * The inode itself has a different generation number than
             * the attribute data.  For now, the best solution is to
             * coerce this to undefined, and let it get cleaned up by
             * the next write or extattrctl clean.
             */
            printf("ufs_extattr_rm (%s): inode number inconsistency (%d, %jd)\n",
                mp->mnt_stat.f_mntonname, ueh.ueh_i_gen, (intmax_t)ip->i_gen);
            error = ENOATTR;
            goto vopunlock_exit;
      }

      /* Flag it as not in use. */
      ueh.ueh_flags = 0;
      ueh.ueh_len = 0;

      local_aiov.iov_base = (caddr_t) &ueh;
      local_aiov.iov_len = sizeof(struct ufs_extattr_header);
      local_aio.uio_iov = &local_aiov;
      local_aio.uio_iovcnt = 1;
      local_aio.uio_rw = UIO_WRITE;
      local_aio.uio_segflg = UIO_SYSSPACE;
      local_aio.uio_td = td;
      local_aio.uio_offset = base_offset;
      local_aio.uio_resid = sizeof(struct ufs_extattr_header);

      ioflag = IO_NODELOCKED;
      if (ufs_extattr_sync)
            ioflag |= IO_SYNC;
      error = VOP_WRITE(attribute->uele_backing_vnode, &local_aio, ioflag,
          ump->um_extattr.uepm_ucred);
      if (error)
            goto vopunlock_exit;

      if (local_aio.uio_resid != 0)
            error = ENXIO;

vopunlock_exit:
      VOP_UNLOCK(attribute->uele_backing_vnode, 0, td);

      return (error);
}

/*
 * Called by UFS when an inode is no longer active and should have its
 * attributes stripped.
 */
void
ufs_extattr_vnode_inactive(struct vnode *vp, struct thread *td)
{
      struct ufs_extattr_list_entry *uele;
      struct mount *mp = vp->v_mount;
      struct ufsmount *ump = VFSTOUFS(mp);

      /*
       * In that case, we cannot lock. We should not have any active vnodes
       * on the fs if this is not yet initialized but is going to be, so
       * this can go unlocked.
       */
      if (!(ump->um_extattr.uepm_flags & UFS_EXTATTR_UEPM_INITIALIZED))
            return;

      ufs_extattr_uepm_lock(ump, td);

      if (!(ump->um_extattr.uepm_flags & UFS_EXTATTR_UEPM_STARTED)) {
            ufs_extattr_uepm_unlock(ump, td);
            return;
      }

      LIST_FOREACH(uele, &ump->um_extattr.uepm_list, uele_entries)
            ufs_extattr_rm(vp, uele->uele_attrnamespace,
                uele->uele_attrname, NULL, td);

      ufs_extattr_uepm_unlock(ump, td);
}

#endif /* !UFS_EXTATTR */

Generated by  Doxygen 1.6.0   Back to index