/* Unmount utility program for Linux CIFS VFS (virtual filesystem) client Copyright (C) 2005 Steve French (sfrench@us.ibm.com) 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 2 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, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #ifndef _GNU_SOURCE #define _GNU_SOURCE #endif #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <ctype.h> #include <sys/types.h> #include <sys/mount.h> #include <sys/ioctl.h> #include <sys/stat.h> #include <sys/vfs.h> #include <fcntl.h> #include <getopt.h> #include <errno.h> #include <string.h> #include <mntent.h> #define UNMOUNT_CIFS_VERSION_MAJOR "0" #define UNMOUNT_CIFS_VERSION_MINOR "5" #ifndef UNMOUNT_CIFS_VENDOR_SUFFIX #ifdef _SAMBA_BUILD_ #include "include/version.h" #ifdef SAMBA_VERSION_VENDOR_SUFFIX #define UNMOUNT_CIFS_VENDOR_SUFFIX "-"SAMBA_VERSION_OFFICIAL_STRING"-"SAMBA_VERSION_VENDOR_SUFFIX #else #define UNMOUNT_CIFS_VENDOR_SUFFIX "-"SAMBA_VERSION_OFFICIAL_STRING #endif /* SAMBA_VERSION_OFFICIAL_STRING and SAMBA_VERSION_VENDOR_SUFFIX */ #else #define UNMOUNT_CIFS_VENDOR_SUFFIX "" #endif /* _SAMBA_BUILD_ */ #endif /* UNMOUNT_CIFS_VENDOR_SUFFIX */ #ifndef MNT_DETACH #define MNT_DETACH 0x02 #endif #ifndef MNT_EXPIRE #define MNT_EXPIRE 0x04 #endif #ifndef MOUNTED_LOCK #define MOUNTED_LOCK "/etc/mtab~" #endif #ifndef MOUNTED_TEMP #define MOUNTED_TEMP "/etc/mtab.tmp" #endif #define CIFS_IOC_CHECKUMOUNT _IO(0xCF, 2) #define CIFS_MAGIC_NUMBER 0xFF534D42 /* the first four bytes of SMB PDU */ static struct option longopts[] = { { "all", 0, NULL, 'a' }, { "help",0, NULL, 'h' }, { "read-only", 0, NULL, 'r' }, { "ro", 0, NULL, 'r' }, { "verbose", 0, NULL, 'v' }, { "version", 0, NULL, 'V' }, { "expire", 0, NULL, 'e' }, { "force", 0, 0, 'f' }, { "lazy", 0, 0, 'l' }, { "no-mtab", 0, 0, 'n' }, { NULL, 0, NULL, 0 } }; const char * thisprogram; int verboseflg = 0; static void umount_cifs_usage(void) { printf("\nUsage: %s <remotetarget> <dir>\n", thisprogram); printf("\nUnmount the specified directory\n"); printf("\nLess commonly used options:"); printf("\n\t-r\tIf mount fails, retry with readonly remount."); printf("\n\t-n\tDo not write to mtab."); printf("\n\t-f\tAttempt a forced unmount, even if the fs is busy."); printf("\n\t-l\tAttempt lazy unmount, Unmount now, cleanup later."); printf("\n\t-v\tEnable verbose mode (may be useful for debugging)."); printf("\n\t-h\tDisplay this help."); printf("\n\nOptions are described in more detail in the manual page"); printf("\n\tman 8 umount.cifs\n"); printf("\nTo display the version number of the cifs umount utility:"); printf("\n\t%s -V\n",thisprogram); printf("\nInvoking the umount utility on cifs mounts, can execute"); printf(" /sbin/umount.cifs (if present and umount -i is not specified.\n"); } static int umount_check_perm(char * dir) { int fileid; int rc; /* allow root to unmount, no matter what */ if(getuid() == 0) return 0; /* presumably can not chdir into the target as we do on mount */ fileid = open(dir, O_RDONLY | O_DIRECTORY | O_NOFOLLOW, 0); if(fileid == -1) { if(verboseflg) printf("error opening mountpoint %d %s",errno,strerror(errno)); return errno; } rc = ioctl(fileid, CIFS_IOC_CHECKUMOUNT, NULL); if(verboseflg) printf("ioctl returned %d with errno %d %s\n",rc,errno,strerror(errno)); if(rc == ENOTTY) { printf("user unmounting via %s is an optional feature of",thisprogram); printf(" the cifs filesystem driver (cifs.ko)"); printf("\n\tand requires cifs.ko version 1.32 or later\n"); } else if (rc > 0) printf("user unmount of %s failed with %d %s\n",dir,errno,strerror(errno)); close(fileid); return rc; } static int lock_mtab(void) { int rc; rc = mknod(MOUNTED_LOCK , 0600, 0); if(rc == -1) printf("\ngetting lock file %s failed with %s\n",MOUNTED_LOCK, strerror(errno)); return rc; } static void unlock_mtab(void) { unlink(MOUNTED_LOCK); } static int remove_from_mtab(char * mountpoint) { int rc; int num_matches; FILE * org_fd; FILE * new_fd; struct mntent * mount_entry; /* Do we need to check if it is a symlink to e.g. /proc/mounts in which case we probably do not want to update it? */ /* Do we first need to check if it is writable? */ if (lock_mtab()) { printf("Mount table locked\n"); return -EACCES; } if(verboseflg) printf("attempting to remove from mtab\n"); org_fd = setmntent(MOUNTED, "r"); if(org_fd == NULL) { printf("Can not open %s\n",MOUNTED); unlock_mtab(); return -EIO; } new_fd = setmntent(MOUNTED_TEMP,"w"); if(new_fd == NULL) { printf("Can not open temp file %s", MOUNTED_TEMP); endmntent(org_fd); unlock_mtab(); return -EIO; } /* BB fix so we only remove the last entry that matches BB */ num_matches = 0; while((mount_entry = getmntent(org_fd)) != NULL) { if(strcmp(mount_entry->mnt_dir, mountpoint) == 0) { num_matches++; } } if(verboseflg) printf("%d matching entries in mount table\n", num_matches); /* Is there a better way to seek back to the first entry in mtab? */ endmntent(org_fd); org_fd = setmntent(MOUNTED, "r"); if(org_fd == NULL) { printf("Can not open %s\n",MOUNTED); unlock_mtab(); return -EIO; } while((mount_entry = getmntent(org_fd)) != NULL) { if(strcmp(mount_entry->mnt_dir, mountpoint) != 0) { addmntent(new_fd, mount_entry); } else { if(num_matches != 1) { addmntent(new_fd, mount_entry); num_matches--; } else if(verboseflg) printf("entry not copied (ie entry is removed)\n"); } } if(verboseflg) printf("done updating tmp file\n"); rc = fchmod (fileno (new_fd), S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH); if(rc < 0) { printf("error %s changing mode of %s\n", strerror(errno), MOUNTED_TEMP); } endmntent(new_fd); rc = rename(MOUNTED_TEMP, MOUNTED); if(rc < 0) { printf("failure %s renaming %s to %s\n",strerror(errno), MOUNTED_TEMP, MOUNTED); unlock_mtab(); return -EIO; } unlock_mtab(); return rc; } int main(int argc, char ** argv) { int c; int rc; int flags = 0; int nomtab = 0; int retry_remount = 0; struct statfs statbuf; char * mountpoint; if(argc && argv) { thisprogram = argv[0]; } else { umount_cifs_usage(); return -EINVAL; } if(argc < 2) { umount_cifs_usage(); return -EINVAL; } if(thisprogram == NULL) thisprogram = "umount.cifs"; /* add sharename in opts string as unc= parm */ while ((c = getopt_long (argc, argv, "afhilnrvV", longopts, NULL)) != -1) { switch (c) { /* No code to do the following option yet */ /* case 'a': ++umount_all; break; */ case '?': case 'h': /* help */ umount_cifs_usage(); exit(1); case 'n': ++nomtab; break; case 'f': flags |= MNT_FORCE; break; case 'l': flags |= MNT_DETACH; /* lazy unmount */ break; case 'e': flags |= MNT_EXPIRE; /* gradually timeout */ break; case 'r': ++retry_remount; break; case 'v': ++verboseflg; break; case 'V': printf ("umount.cifs version: %s.%s%s\n", UNMOUNT_CIFS_VERSION_MAJOR, UNMOUNT_CIFS_VERSION_MINOR, UNMOUNT_CIFS_VENDOR_SUFFIX); exit (0); default: printf("unknown unmount option %c\n",c); umount_cifs_usage(); exit(1); } } /* move past the umount options */ argv += optind; argc -= optind; mountpoint = argv[0]; if((argc < 1) || (argv[0] == NULL)) { printf("\nMissing name of unmount directory\n"); umount_cifs_usage(); return -EINVAL; } if(verboseflg) printf("optind %d unmount dir %s\n",optind, mountpoint); /* check if running effectively root */ if(geteuid() != 0) { printf("Trying to unmount when %s not installed suid\n",thisprogram); if(verboseflg) printf("euid = %d\n",geteuid()); return -EACCES; } /* fixup path if needed */ /* make sure that this is a cifs filesystem */ rc = statfs(mountpoint, &statbuf); if(rc || (statbuf.f_type != CIFS_MAGIC_NUMBER)) { printf("This utility only unmounts cifs filesystems.\n"); return -EINVAL; } /* check if our uid was the one who mounted */ rc = umount_check_perm(mountpoint); if (rc) { printf("Not permitted to unmount\n"); return rc; } if(umount2(mountpoint, flags)) { /* remember to kill daemon on error */ switch (errno) { case 0: printf("unmount failed but no error number set\n"); break; default: printf("unmount error %d = %s\n",errno,strerror(errno)); } printf("Refer to the umount.cifs(8) manual page (man 8 umount.cifs)\n"); return -1; } else { if(verboseflg) printf("umount2 succeeded\n"); if(nomtab == 0) remove_from_mtab(mountpoint); } return 0; }