source/client/umount.cifs.c

   1 /*
   2    Unmount utility program for Linux CIFS VFS (virtual filesystem) client
   3    Copyright (C) 2005 Steve French  (sfrench@us.ibm.com)
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  18
  19 #ifndef _GNU_SOURCE
  20 #define _GNU_SOURCE
  21 #endif
  22
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include <unistd.h>
  26 #include <ctype.h>
  27 #include <sys/types.h>
  28 #include <sys/mount.h>
  29 #include <sys/ioctl.h>
  30 #include <sys/stat.h>
  31 #include <sys/vfs.h>
  32 #include <fcntl.h>
  33 #include <getopt.h>
  34 #include <errno.h>
  35 #include <string.h>
  36 #include <mntent.h>
  37
  38 #define UNMOUNT_CIFS_VERSION_MAJOR "0"
  39 #define UNMOUNT_CIFS_VERSION_MINOR "2"
  40
  41 #ifndef UNMOUNT_CIFS_VENDOR_SUFFIX
  42 #define UNMOUNT_CIFS_VENDOR_SUFFIX ""
  43 #endif
  44
  45 #ifndef MNT_DETACH
  46 #define MNT_DETACH 0x02
  47 #endif
  48
  49 #ifndef MNT_EXPIRE
  50 #define MNT_EXPIRE 0x04
  51 #endif
  52
  53 #define CIFS_IOC_CHECKUMOUNT _IO(0xCF, 2)
  54 #define CIFS_MAGIC_NUMBER 0xFF534D42   /* the first four bytes of SMB PDU */
  55
  56 static struct option longopts[] = {
  57         { "all", 0, NULL, 'a' },
  58         { "help",0, NULL, 'h' },
  59         { "read-only", 0, NULL, 'r' },
  60         { "ro", 0, NULL, 'r' },
  61         { "verbose", 0, NULL, 'v' },
  62         { "version", 0, NULL, 'V' },
  63         { "expire", 0, NULL, 'e' },
  64         { "force", 0, 0, 'f' },
  65         { "lazy", 0, 0, 'l' },
  66         { "no-mtab", 0, 0, 'n' },
  67         { NULL, 0, NULL, 0 }
  68 };
  69
  70 char * thisprogram;
  71 int verboseflg = 0;
  72
  73 static void umount_cifs_usage(void)
  74 {
  75         printf("\nUsage:  %s <remotetarget> <dir>\n", thisprogram);
  76         printf("\nUnmount the specified directory\n");
  77         printf("\nLess commonly used options:");
  78         printf("\n\t-r\tIf mount fails, retry with readonly remount.");
  79         printf("\n\t-n\tDo not write to mtab.");
  80         printf("\n\t-f\tAttempt a forced unmount, even if the fs is busy.");
  81         printf("\n\t-l\tAttempt lazy unmount, Unmount now, cleanup later.");
  82         printf("\n\t-v\tEnable verbose mode (may be useful for debugging).");
  83         printf("\n\t-h\tDisplay this help.");
  84         printf("\n\nOptions are described in more detail in the manual page");
  85         printf("\n\tman 8 umount.cifs\n");
  86         printf("\nTo display the version number of the cifs umount utility:");
  87         printf("\n\t%s -V\n",thisprogram);
  88 }
  89
  90 static int umount_check_perm(char * dir)
  91 {
  92         int fileid;
  93         int rc;
  94
  95         /* presumably can not chdir into the target as we do on mount */
  96
  97         fileid = open(dir, O_RDONLY | O_DIRECTORY | O_NOFOLLOW, 0);
  98         if(fileid == -1) {
  99                 if(verboseflg)
 100                         printf("error opening mountpoint %d %s",errno,strerror(errno));
 101                 return errno;
 102         }
 103
 104         rc = ioctl(fileid, CIFS_IOC_CHECKUMOUNT, NULL);
 105
 106         if(verboseflg)
 107                 printf("ioctl returned %d with errno %d %s\n",rc,errno,strerror(errno));
 108
 109         if(rc == ENOTTY)
 110                 printf("user unmounting via %s is an optional feature of the cifs filesystem driver (cifs.ko)\n\tand requires cifs.ko version 1.32 or later\n",thisprogram);
 111         else if (rc > 0)
 112                 printf("user unmount of %s failed with %d %s\n",dir,errno,strerror(errno));
 113         close(fileid);
 114
 115         return rc;
 116 }
 117
 118 int main(int argc, char ** argv)
 119 {
 120         int c;
 121         int rc;
 122         int flags = 0;
 123         int nomtab = 0;
 124         int retry_remount = 0;
 125         struct mntent mountent;
 126         struct statfs statbuf;
 127         char * mountpoint;
 128         FILE * pmntfile;
 129
 130         if(argc && argv) {
 131                 thisprogram = argv[0];
 132         } else {
 133                 umount_cifs_usage();
 134                 return -EINVAL;
 135         }
 136
 137         if(argc < 2) {
 138                 umount_cifs_usage();
 139                 return -EINVAL;
 140         }
 141
 142         if(thisprogram == NULL)
 143                 thisprogram = "umount.cifs";
 144
 145         /* add sharename in opts string as unc= parm */
 146
 147         while ((c = getopt_long (argc, argv, "afhilnrvV",
 148                          longopts, NULL)) != -1) {
 149                 switch (c) {
 150 /* No code to do the following  option yet */
 151 /*              case 'a':
 152                         ++umount_all;
 153                         break; */
 154                 case '?':
 155                 case 'h':   /* help */
 156                         umount_cifs_usage();
 157                         exit(1);
 158                 case 'n':
 159                         ++nomtab;
 160                         break;
 161                 case 'f':
 162                         flags |= MNT_FORCE;
 163                         break;
 164                 case 'l':
 165                         flags |= MNT_DETACH; /* lazy unmount */
 166                         break;
 167                 case 'e':
 168                         flags |= MNT_EXPIRE; /* gradually timeout */
 169                         break;
 170                 case 'r':
 171                         ++retry_remount;
 172                         break;
 173                 case 'v':
 174                         ++verboseflg;
 175                         break;
 176                 case 'V':
 177                         printf ("umount.cifs version: %s.%s%s\n",
 178                                 UNMOUNT_CIFS_VERSION_MAJOR,
 179                                 UNMOUNT_CIFS_VERSION_MINOR,
 180                                 UNMOUNT_CIFS_VENDOR_SUFFIX);
 181                         exit (0);
 182                 default:
 183                         printf("unknown unmount option %c\n",c);
 184                         umount_cifs_usage();
 185                         exit(1);
 186                 }
 187         }
 188
 189         /* move past the umount options */
 190         argv += optind;
 191         argc -= optind;
 192
 193         mountpoint = argv[0];
 194
 195         if((argc < 1) || (argv[0] == NULL)) {
 196                 printf("\nMissing name of unmount directory\n");
 197                 umount_cifs_usage();
 198                 return -EINVAL;
 199         }
 200
 201         if(verboseflg)
 202                 printf("optind %d unmount dir %s\n",optind, mountpoint);
 203
 204         /* check if running effectively root */
 205         if(geteuid() != 0) {
 206                 printf("Trying to unmount when %s not installed suid\n",thisprogram);
 207                 if(verboseflg)
 208                         printf("euid = %d\n",geteuid());
 209                 return -EACCES;
 210         }
 211
 212         /* fixup path if needed */
 213
 214         /* make sure that this is a cifs filesystem */
 215         rc = statfs(mountpoint, &statbuf);
 216
 217         if(rc || (statbuf.f_type != CIFS_MAGIC_NUMBER)) {
 218                 printf("Wrong filesystem. This utility only unmounts cifs filesystems.\n");
 219                 return -EINVAL;
 220         }
 221
 222         /* check if our uid was the one who mounted */
 223         rc = umount_check_perm(mountpoint);
 224         if (rc) {
 225                 printf("Not permitted to unmount\n");
 226                 return rc;
 227         }
 228
 229         if(umount2(mountpoint, flags)) {
 230         /* remember to kill daemon on error */
 231                 switch (errno) {
 232                 case 0:
 233                         printf("unmount failed but no error number set\n");
 234                         break;
 235                 default:
 236                         printf("unmount error %d = %s\n",errno,strerror(errno));
 237                 }
 238                 printf("Refer to the umount.cifs(8) manual page (e.g.man 8 umount.cifs)\n");
 239                 return -1;
 240         } else {
 241                 pmntfile = setmntent(MOUNTED, "a+");
 242                 if(pmntfile) {
 243 /*                      mountent.mnt_fsname = share_name;
 244                         mountent.mnt_dir = mountpoint;
 245                         mountent.mnt_type = "cifs";
 246                         mountent.mnt_opts = malloc(220);
 247                         if(mountent.mnt_opts) {
 248                                 char * mount_user = getusername();
 249                                 memset(mountent.mnt_opts,0,200);
 250                                 if(flags & MS_RDONLY)
 251                                         strcat(mountent.mnt_opts,"ro");
 252                                 else
 253                                         strcat(mountent.mnt_opts,"rw");
 254                                 if(flags & MS_MANDLOCK)
 255                                         strcat(mountent.mnt_opts,",mand");
 256                                 else
 257                                         strcat(mountent.mnt_opts,",nomand");
 258                                 if(flags & MS_NOEXEC)
 259                                         strcat(mountent.mnt_opts,",noexec");
 260                                 if(flags & MS_NOSUID)
 261                                         strcat(mountent.mnt_opts,",nosuid");
 262                                 if(flags & MS_NODEV)
 263                                         strcat(mountent.mnt_opts,",nodev");
 264                                 if(flags & MS_SYNCHRONOUS)
 265                                         strcat(mountent.mnt_opts,",synch");
 266                                 if(mount_user) {
 267                                         if(getuid() != 0) {
 268                                                 strcat(mountent.mnt_opts,",user=");
 269                                                 strcat(mountent.mnt_opts,mount_user);
 270                                         }
 271                                         free(mount_user);
 272                                 }
 273                         }
 274                         mountent.mnt_freq = 0;
 275                         mountent.mnt_passno = 0;
 276                         rc = addmntent(pmntfile,&mountent);
 277                         endmntent(pmntfile);
 278                         if(mountent.mnt_opts)
 279                                 free(mountent.mnt_opts);*/
 280                 } else {
 281                     printf("could not update mount table\n");
 282                 }
 283         }
 284
 285         return 0;
 286 }
 287