source3/modules/vfs_crossrename.c

   1 /*
   2  * Copyright (c) Björn Jacke 2010
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "includes.h"
  19 #include "smbd/smbd.h"
  20 #include "system/filesys.h"
  21 #include "transfer_file.h"
  22 #include "smbprofile.h"
  23
  24 #define MODULE "crossrename"
  25 static off_t module_sizelimit;
  26
  27 static int crossrename_connect(
  28                 struct vfs_handle_struct *  handle,
  29                 const char *                service,
  30                 const char *                user)
  31 {
  32         int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
  33
  34         if (ret < 0) {
  35                 return ret;
  36         }
  37
  38         module_sizelimit = (off_t) lp_parm_int(SNUM(handle->conn),
  39                                         MODULE, "sizelimit", 20);
  40         /* convert from MiB to byte: */
  41         module_sizelimit *= 1048576;
  42
  43         return 0;
  44 }
  45
  46 /*********************************************************
  47  For rename across filesystems initial Patch from Warren Birnbaum
  48  <warrenb@hpcvscdp.cv.hp.com>
  49 **********************************************************/
  50
  51 static int copy_reg(const char *source, const char *dest)
  52 {
  53         SMB_STRUCT_STAT source_stats;
  54         int saved_errno;
  55         int ifd = -1;
  56         int ofd = -1;
  57
  58         if (sys_lstat(source, &source_stats, false) == -1)
  59                 return -1;
  60
  61         if (!S_ISREG (source_stats.st_ex_mode))
  62                 return -1;
  63
  64         if (source_stats.st_ex_size > module_sizelimit) {
  65                 DEBUG(5,
  66                         ("%s: size of %s larger than sizelimit (%lld > %lld), rename prohititted\n",
  67                         MODULE, source,
  68                         (long long)source_stats.st_ex_size,
  69                         (long long)module_sizelimit));
  70                 return -1;
  71         }
  72
  73         if((ifd = open (source, O_RDONLY, 0)) < 0)
  74                 return -1;
  75
  76         if (unlink (dest) && errno != ENOENT) {
  77                 close(ifd);
  78                 return -1;
  79         }
  80
  81 #ifdef O_NOFOLLOW
  82         if((ofd = open (dest, O_WRONLY | O_CREAT | O_TRUNC | O_NOFOLLOW, 0600)) < 0 )
  83 #else
  84         if((ofd = open (dest, O_WRONLY | O_CREAT | O_TRUNC , 0600)) < 0 )
  85 #endif
  86                 goto err;
  87
  88         if (transfer_file(ifd, ofd, source_stats.st_ex_size) == -1)
  89                 goto err;
  90
  91         /*
  92          * Try to preserve ownership.  For non-root it might fail, but that's ok.
  93          * But root probably wants to know, e.g. if NFS disallows it.
  94          */
  95
  96 #ifdef HAVE_FCHOWN
  97         if ((fchown(ofd, source_stats.st_ex_uid, source_stats.st_ex_gid) == -1) && (errno != EPERM))
  98 #else
  99         if ((chown(dest, source_stats.st_ex_uid, source_stats.st_ex_gid) == -1) && (errno != EPERM))
 100 #endif
 101                 goto err;
 102
 103         /*
 104          * fchown turns off set[ug]id bits for non-root,
 105          * so do the chmod last.
 106          */
 107
 108 #if defined(HAVE_FCHMOD)
 109         if ((fchmod (ofd, source_stats.st_ex_mode & 07777) == -1) &&
 110                         (errno != EPERM))
 111 #else
 112         if ((chmod (dest, source_stats.st_ex_mode & 07777) == -1) &&
 113                         (errno != EPERM))
 114 #endif
 115                 goto err;
 116
 117         if (close (ifd) == -1)
 118                 goto err;
 119
 120         if (close (ofd) == -1)
 121                 return -1;
 122
 123         /* Try to copy the old file's modtime and access time.  */
 124 #if defined(HAVE_UTIMENSAT)
 125         {
 126                 struct timespec ts[2];
 127
 128                 ts[0] = source_stats.st_ex_atime;
 129                 ts[1] = source_stats.st_ex_mtime;
 130                 utimensat(AT_FDCWD, dest, ts, AT_SYMLINK_NOFOLLOW);
 131         }
 132 #elif defined(HAVE_UTIMES)
 133         {
 134                 struct timeval tv[2];
 135
 136                 tv[0] = convert_timespec_to_timeval(source_stats.st_ex_atime);
 137                 tv[1] = convert_timespec_to_timeval(source_stats.st_ex_mtime);
 138 #ifdef HAVE_LUTIMES
 139                 lutimes(dest, tv);
 140 #else
 141                 utimes(dest, tv);
 142 #endif
 143         }
 144 #elif defined(HAVE_UTIME)
 145         {
 146                 struct utimbuf tv;
 147
 148                 tv.actime = convert_timespec_to_time_t(source_stats.st_ex_atime);
 149                 tv.modtime = convert_timespec_to_time_t(source_stats.st_ex_mtime);
 150                 utime(dest, &tv);
 151         }
 152 #endif
 153
 154         if (unlink (source) == -1)
 155                 return -1;
 156
 157         return 0;
 158
 159   err:
 160
 161         saved_errno = errno;
 162         if (ifd != -1)
 163                 close(ifd);
 164         if (ofd != -1)
 165                 close(ofd);
 166         errno = saved_errno;
 167         return -1;
 168 }
 169
 170
 171 static int crossrename_rename(vfs_handle_struct *handle,
 172                           const struct smb_filename *smb_fname_src,
 173                           const struct smb_filename *smb_fname_dst)
 174 {
 175         int result = -1;
 176
 177         START_PROFILE(syscall_rename);
 178
 179         if (smb_fname_src->stream_name || smb_fname_dst->stream_name) {
 180                 errno = ENOENT;
 181                 goto out;
 182         }
 183
 184         result = rename(smb_fname_src->base_name, smb_fname_dst->base_name);
 185         if ((result == -1) && (errno == EXDEV)) {
 186                 /* Rename across filesystems needed. */
 187                 result = copy_reg(smb_fname_src->base_name,
 188                                   smb_fname_dst->base_name);
 189         }
 190
 191  out:
 192         END_PROFILE(syscall_rename);
 193         return result;
 194 }
 195
 196 static struct vfs_fn_pointers vfs_crossrename_fns = {
 197         .connect_fn = crossrename_connect,
 198         .rename_fn = crossrename_rename
 199 };
 200
 201 NTSTATUS vfs_crossrename_init(void);
 202 NTSTATUS vfs_crossrename_init(void)
 203 {
 204         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, MODULE,
 205                                 &vfs_crossrename_fns);
 206 }
 207