source: vendor/current/source3/modules/vfs_crossrename.c

/*
 * Copyright (c) Björn Jacke 2010
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "includes.h"
#include "smbd/smbd.h"
#include "system/filesys.h"
#include "transfer_file.h"
#include "smbprofile.h"

#define MODULE "crossrename"
static off_t module_sizelimit;

static int crossrename_connect(
                struct vfs_handle_struct *  handle,
                const char *                service,
                const char *                user)
{
        int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);

        if (ret < 0) {
                return ret;
        }

        module_sizelimit = (off_t) lp_parm_int(SNUM(handle->conn),
                                        MODULE, "sizelimit", 20);
        /* convert from MiB to byte: */
        module_sizelimit *= 1048576;

        return 0;
}

/*********************************************************
 For rename across filesystems initial Patch from Warren Birnbaum
 <warrenb@hpcvscdp.cv.hp.com>
**********************************************************/

static int copy_reg(const char *source, const char *dest)
{
        SMB_STRUCT_STAT source_stats;
        int saved_errno;
        int ifd = -1;
        int ofd = -1;

        if (sys_lstat(source, &source_stats, false) == -1)
                return -1;

        if (!S_ISREG (source_stats.st_ex_mode))
                return -1;

        if (source_stats.st_ex_size > module_sizelimit) {
                DEBUG(5,
                        ("%s: size of %s larger than sizelimit (%lld > %lld), rename prohititted\n",
                        MODULE, source,
                        (long long)source_stats.st_ex_size,
                        (long long)module_sizelimit));
                return -1;
        }

        if((ifd = open (source, O_RDONLY, 0)) < 0)
                return -1;

        if (unlink (dest) && errno != ENOENT) {
                close(ifd);
                return -1;
        }

#ifdef O_NOFOLLOW
        if((ofd = open (dest, O_WRONLY | O_CREAT | O_TRUNC | O_NOFOLLOW, 0600)) < 0 )
#else
        if((ofd = open (dest, O_WRONLY | O_CREAT | O_TRUNC , 0600)) < 0 )
#endif
                goto err;

        if (transfer_file(ifd, ofd, source_stats.st_ex_size) == -1)
                goto err;

        /*
         * Try to preserve ownership.  For non-root it might fail, but that's ok.
         * But root probably wants to know, e.g. if NFS disallows it.
         */

#ifdef HAVE_FCHOWN
        if ((fchown(ofd, source_stats.st_ex_uid, source_stats.st_ex_gid) == -1) && (errno != EPERM))
#else
        if ((chown(dest, source_stats.st_ex_uid, source_stats.st_ex_gid) == -1) && (errno != EPERM))
#endif
                goto err;

        /*
         * fchown turns off set[ug]id bits for non-root,
         * so do the chmod last.
         */

#if defined(HAVE_FCHMOD)
        if ((fchmod (ofd, source_stats.st_ex_mode & 07777) == -1) &&
                        (errno != EPERM))
#else
        if ((chmod (dest, source_stats.st_ex_mode & 07777) == -1) &&
                        (errno != EPERM))
#endif
                goto err;

        if (close (ifd) == -1)
                goto err;

        if (close (ofd) == -1)
                return -1;

        /* Try to copy the old file's modtime and access time.  */
#if defined(HAVE_UTIMENSAT)
        {
                struct timespec ts[2];

                ts[0] = source_stats.st_ex_atime;
                ts[1] = source_stats.st_ex_mtime;
                utimensat(AT_FDCWD, dest, ts, AT_SYMLINK_NOFOLLOW);
        }
#elif defined(HAVE_UTIMES)
        {
                struct timeval tv[2];

                tv[0] = convert_timespec_to_timeval(source_stats.st_ex_atime);
                tv[1] = convert_timespec_to_timeval(source_stats.st_ex_mtime);
#ifdef HAVE_LUTIMES
                lutimes(dest, tv);
#else
                utimes(dest, tv);
#endif
        }
#elif defined(HAVE_UTIME)
        {
                struct utimbuf tv;

                tv.actime = convert_timespec_to_time_t(source_stats.st_ex_atime);
                tv.modtime = convert_timespec_to_time_t(source_stats.st_ex_mtime);
                utime(dest, &tv);
        }
#endif

        if (unlink (source) == -1)
                return -1;

        return 0;

  err:

        saved_errno = errno;
        if (ifd != -1)
                close(ifd);
        if (ofd != -1)
                close(ofd);
        errno = saved_errno;
        return -1;
}


static int crossrename_rename(vfs_handle_struct *handle,
                          const struct smb_filename *smb_fname_src,
                          const struct smb_filename *smb_fname_dst)
{
        int result = -1;

        START_PROFILE(syscall_rename);

        if (smb_fname_src->stream_name || smb_fname_dst->stream_name) {
                errno = ENOENT;
                goto out;
        }

        result = rename(smb_fname_src->base_name, smb_fname_dst->base_name);
        if ((result == -1) && (errno == EXDEV)) {
                /* Rename across filesystems needed. */
                result = copy_reg(smb_fname_src->base_name,
                                  smb_fname_dst->base_name);
        }

 out:
        END_PROFILE(syscall_rename);
        return result;
}

static struct vfs_fn_pointers vfs_crossrename_fns = {
        .connect_fn = crossrename_connect,
        .rename_fn = crossrename_rename
};

NTSTATUS vfs_crossrename_init(void);
NTSTATUS vfs_crossrename_init(void)
{
        return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, MODULE,
                                &vfs_crossrename_fns);
}