source3/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 3 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, see <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _GNU_SOURCE
  19 #define _GNU_SOURCE
  20 #endif
  21
  22 #include <stdlib.h>
  23 #include <stdio.h>
  24 #include <unistd.h>
  25 #include <ctype.h>
  26 #include <sys/types.h>
  27 #include <sys/mount.h>
  28 #include <sys/ioctl.h>
  29 #include <sys/stat.h>
  30 #include <sys/vfs.h>
  31 #include <fcntl.h>
  32 #include <getopt.h>
  33 #include <errno.h>
  34 #include <string.h>
  35 #include <mntent.h>
  36 #include "mount.h"
  37
  38 #define UNMOUNT_CIFS_VERSION_MAJOR "0"
  39 #define UNMOUNT_CIFS_VERSION_MINOR "6"
  40
  41 #ifndef UNMOUNT_CIFS_VENDOR_SUFFIX
  42  #ifdef _SAMBA_BUILD_
  43   #include "include/version.h"
  44   #ifdef SAMBA_VERSION_VENDOR_SUFFIX
  45    #define UNMOUNT_CIFS_VENDOR_SUFFIX "-"SAMBA_VERSION_OFFICIAL_STRING"-"SAMBA_VERSION_VENDOR_SUFFIX
  46   #else
  47    #define UNMOUNT_CIFS_VENDOR_SUFFIX "-"SAMBA_VERSION_OFFICIAL_STRING
  48   #endif /* SAMBA_VERSION_OFFICIAL_STRING and SAMBA_VERSION_VENDOR_SUFFIX */
  49  #else
  50   #define UNMOUNT_CIFS_VENDOR_SUFFIX ""
  51  #endif /* _SAMBA_BUILD_ */
  52 #endif /* UNMOUNT_CIFS_VENDOR_SUFFIX */
  53
  54 #ifndef MNT_DETACH
  55 #define MNT_DETACH 0x02
  56 #endif
  57
  58 #ifndef MNT_EXPIRE
  59 #define MNT_EXPIRE 0x04
  60 #endif
  61
  62 #ifndef MOUNTED_LOCK
  63 #define MOUNTED_LOCK    "/etc/mtab~"
  64 #endif
  65 #ifndef MOUNTED_TEMP
  66 #define MOUNTED_TEMP    "/etc/mtab.tmp"
  67 #endif
  68
  69 #define CIFS_IOC_CHECKUMOUNT _IO(0xCF, 2)
  70 #define CIFS_MAGIC_NUMBER 0xFF534D42   /* the first four bytes of SMB PDU */
  71
  72 static struct option longopts[] = {
  73         { "all", 0, NULL, 'a' },
  74         { "help",0, NULL, 'h' },
  75         { "read-only", 0, NULL, 'r' },
  76         { "ro", 0, NULL, 'r' },
  77         { "verbose", 0, NULL, 'v' },
  78         { "version", 0, NULL, 'V' },
  79         { "expire", 0, NULL, 'e' },
  80         { "force", 0, 0, 'f' },
  81         { "lazy", 0, 0, 'l' },
  82         { "no-mtab", 0, 0, 'n' },
  83         { NULL, 0, NULL, 0 }
  84 };
  85
  86 const char * thisprogram;
  87 int verboseflg = 0;
  88
  89 static void umount_cifs_usage(void)
  90 {
  91         printf("\nUsage:  %s <remotetarget> <dir>\n", thisprogram);
  92         printf("\nUnmount the specified directory\n");
  93         printf("\nLess commonly used options:");
  94         printf("\n\t-r\tIf mount fails, retry with readonly remount.");
  95         printf("\n\t-n\tDo not write to mtab.");
  96         printf("\n\t-f\tAttempt a forced unmount, even if the fs is busy.");
  97         printf("\n\t-l\tAttempt lazy unmount, Unmount now, cleanup later.");
  98         printf("\n\t-v\tEnable verbose mode (may be useful for debugging).");
  99         printf("\n\t-h\tDisplay this help.");
 100         printf("\n\nOptions are described in more detail in the manual page");
 101         printf("\n\tman 8 umount.cifs\n");
 102         printf("\nTo display the version number of the cifs umount utility:");
 103         printf("\n\t%s -V\n",thisprogram);
 104         printf("\nInvoking the umount utility on cifs mounts, can execute");
 105         printf(" /sbin/umount.cifs (if present and umount -i is not specified.\n");
 106 }
 107
 108 static int umount_check_perm(char * dir)
 109 {
 110         int fileid;
 111         int rc;
 112
 113         /* allow root to unmount, no matter what */
 114         if(getuid() == 0)
 115                 return 0;
 116
 117         /* presumably can not chdir into the target as we do on mount */
 118         fileid = open(dir, O_RDONLY | O_DIRECTORY | O_NOFOLLOW, 0);
 119         if(fileid == -1) {
 120                 if(verboseflg)
 121                         printf("error opening mountpoint %d %s",errno,strerror(errno));
 122                 return errno;
 123         }
 124
 125         rc = ioctl(fileid, CIFS_IOC_CHECKUMOUNT, NULL);
 126
 127         if(verboseflg)
 128                 printf("ioctl returned %d with errno %d %s\n",rc,errno,strerror(errno));
 129
 130         if(rc == ENOTTY) {
 131                 printf("user unmounting via %s is an optional feature of",thisprogram);
 132                 printf(" the cifs filesystem driver (cifs.ko)");
 133                 printf("\n\tand requires cifs.ko version 1.32 or later\n");
 134         } else if (rc != 0)
 135                 printf("user unmount of %s failed with %d %s\n",dir,errno,strerror(errno));
 136         close(fileid);
 137
 138         return rc;
 139 }
 140
 141 static int remove_from_mtab(char * mountpoint)
 142 {
 143         int rc;
 144         int num_matches;
 145         FILE * org_fd;
 146         FILE * new_fd;
 147         struct mntent * mount_entry;
 148
 149         /* Do we need to check if it is a symlink to e.g. /proc/mounts
 150         in which case we probably do not want to update it? */
 151
 152         /* Do we first need to check if it is writable? */
 153
 154         atexit(unlock_mtab);
 155         if (lock_mtab()) {
 156                 printf("Mount table locked\n");
 157                 return -EACCES;
 158         }
 159
 160         if(verboseflg)
 161                 printf("attempting to remove from mtab\n");
 162
 163         org_fd = setmntent(MOUNTED, "r");
 164
 165         if(org_fd == NULL) {
 166                 printf("Can not open %s\n",MOUNTED);
 167                 unlock_mtab();
 168                 return -EIO;
 169         }
 170
 171         new_fd = setmntent(MOUNTED_TEMP,"w");
 172         if(new_fd == NULL) {
 173                 printf("Can not open temp file %s", MOUNTED_TEMP);
 174                 endmntent(org_fd);
 175                 unlock_mtab();
 176                 return -EIO;
 177         }
 178
 179         /* BB fix so we only remove the last entry that matches BB */
 180         num_matches = 0;
 181         while((mount_entry = getmntent(org_fd)) != NULL) {
 182                 if(strcmp(mount_entry->mnt_dir, mountpoint) == 0) {
 183                         num_matches++;
 184                 }
 185         }
 186         if(verboseflg)
 187                 printf("%d matching entries in mount table\n", num_matches);
 188
 189         /* Is there a better way to seek back to the first entry in mtab? */
 190         endmntent(org_fd);
 191         org_fd = setmntent(MOUNTED, "r");
 192
 193         if(org_fd == NULL) {
 194                 printf("Can not open %s\n",MOUNTED);
 195                 unlock_mtab();
 196                 return -EIO;
 197         }
 198
 199         while((mount_entry = getmntent(org_fd)) != NULL) {
 200                 if(strcmp(mount_entry->mnt_dir, mountpoint) != 0) {
 201                         addmntent(new_fd, mount_entry);
 202                 } else {
 203                         if(num_matches != 1) {
 204                                 addmntent(new_fd, mount_entry);
 205                                 num_matches--;
 206                         } else if(verboseflg)
 207                                 printf("entry not copied (ie entry is removed)\n");
 208                 }
 209         }
 210
 211         if(verboseflg)
 212                 printf("done updating tmp file\n");
 213         rc = fchmod (fileno (new_fd), S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
 214         if(rc < 0) {
 215                 printf("error %s changing mode of %s\n", strerror(errno),
 216                         MOUNTED_TEMP);
 217         }
 218         endmntent(new_fd);
 219
 220         rc = rename(MOUNTED_TEMP, MOUNTED);
 221
 222         if(rc < 0) {
 223                 printf("failure %s renaming %s to %s\n",strerror(errno),
 224                         MOUNTED_TEMP, MOUNTED);
 225                 unlock_mtab();
 226                 return -EIO;
 227         }
 228
 229         unlock_mtab();
 230
 231         return rc;
 232 }
 233
 234 int main(int argc, char ** argv)
 235 {
 236         int c;
 237         int rc;
 238         int flags = 0;
 239         int nomtab = 0;
 240         int retry_remount = 0;
 241         struct statfs statbuf;
 242         char * mountpoint;
 243
 244         if(argc && argv) {
 245                 thisprogram = argv[0];
 246         } else {
 247                 umount_cifs_usage();
 248                 return -EINVAL;
 249         }
 250
 251         if(argc < 2) {
 252                 umount_cifs_usage();
 253                 return -EINVAL;
 254         }
 255
 256         if(thisprogram == NULL)
 257                 thisprogram = "umount.cifs";
 258
 259         /* add sharename in opts string as unc= parm */
 260
 261         while ((c = getopt_long (argc, argv, "afhilnrvV",
 262                          longopts, NULL)) != -1) {
 263                 switch (c) {
 264 /* No code to do the following  option yet */
 265 /*              case 'a':
 266                         ++umount_all;
 267                         break; */
 268                 case '?':
 269                 case 'h':   /* help */
 270                         umount_cifs_usage();
 271                         exit(1);
 272                 case 'n':
 273                         ++nomtab;
 274                         break;
 275                 case 'f':
 276                         flags |= MNT_FORCE;
 277                         break;
 278                 case 'l':
 279                         flags |= MNT_DETACH; /* lazy unmount */
 280                         break;
 281                 case 'e':
 282                         flags |= MNT_EXPIRE; /* gradually timeout */
 283                         break;
 284                 case 'r':
 285                         ++retry_remount;
 286                         break;
 287                 case 'v':
 288                         ++verboseflg;
 289                         break;
 290                 case 'V':
 291                         printf ("umount.cifs version: %s.%s%s\n",
 292                                 UNMOUNT_CIFS_VERSION_MAJOR,
 293                                 UNMOUNT_CIFS_VERSION_MINOR,
 294                                 UNMOUNT_CIFS_VENDOR_SUFFIX);
 295                         exit (0);
 296                 default:
 297                         printf("unknown unmount option %c\n",c);
 298                         umount_cifs_usage();
 299                         exit(1);
 300                 }
 301         }
 302
 303         /* move past the umount options */
 304         argv += optind;
 305         argc -= optind;
 306
 307         mountpoint = argv[0];
 308
 309         if((argc < 1) || (argv[0] == NULL)) {
 310                 printf("\nMissing name of unmount directory\n");
 311                 umount_cifs_usage();
 312                 return -EINVAL;
 313         }
 314
 315         if(verboseflg)
 316                 printf("optind %d unmount dir %s\n",optind, mountpoint);
 317
 318         /* check if running effectively root */
 319         if(geteuid() != 0) {
 320                 printf("Trying to unmount when %s not installed suid\n",thisprogram);
 321                 if(verboseflg)
 322                         printf("euid = %d\n",geteuid());
 323                 return -EACCES;
 324         }
 325
 326         /* fixup path if needed */
 327
 328         /* Trim any trailing slashes */
 329         while ((strlen(mountpoint) > 1) &&
 330                 (mountpoint[strlen(mountpoint)-1] == '/'))
 331         {
 332                 mountpoint[strlen(mountpoint)-1] = '\0';
 333         }
 334
 335         /* make sure that this is a cifs filesystem */
 336         rc = statfs(mountpoint, &statbuf);
 337
 338         if(rc || (statbuf.f_type != CIFS_MAGIC_NUMBER)) {
 339                 printf("This utility only unmounts cifs filesystems.\n");
 340                 return -EINVAL;
 341         }
 342
 343         /* check if our uid was the one who mounted */
 344         rc = umount_check_perm(mountpoint);
 345         if (rc) {
 346                 printf("Not permitted to unmount\n");
 347                 return rc;
 348         }
 349
 350         if(umount2(mountpoint, flags)) {
 351         /* remember to kill daemon on error */
 352                 switch (errno) {
 353                 case 0:
 354                         printf("unmount failed but no error number set\n");
 355                         break;
 356                 default:
 357                         printf("unmount error %d = %s\n",errno,strerror(errno));
 358                 }
 359                 printf("Refer to the umount.cifs(8) manual page (man 8 umount.cifs)\n");
 360                 return -1;
 361         } else {
 362                 if(verboseflg)
 363                         printf("umount2 succeeded\n");
 364                 if(nomtab == 0)
 365                         remove_from_mtab(mountpoint);
 366         }
 367
 368         return 0;
 369 }
 370