diff options
Diffstat (limited to 'client/umount.cifs.c')
| -rw-r--r-- | client/umount.cifs.c | 405 |
1 files changed, 405 insertions, 0 deletions
diff --git a/client/umount.cifs.c b/client/umount.cifs.c new file mode 100644 index 0000000000..0005054467 --- /dev/null +++ b/client/umount.cifs.c @@ -0,0 +1,405 @@ +/* + 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 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/>. */ + +#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> +#include <limits.h> +#include "mount.h" + +#define UNMOUNT_CIFS_VERSION_MAJOR "0" +#define UNMOUNT_CIFS_VERSION_MINOR "6" + +#ifndef UNMOUNT_CIFS_VENDOR_SUFFIX + #ifdef _SAMBA_BUILD_ + #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 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? */ + + atexit(unlock_mtab); + 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; +} + +/* Make a canonical pathname from PATH. Returns a freshly malloced string. + It is up the *caller* to ensure that the PATH is sensible. i.e. + canonicalize ("/dev/fd0/.") returns "/dev/fd0" even though ``/dev/fd0/.'' + is not a legal pathname for ``/dev/fd0'' Anything we cannot parse + we return unmodified. */ +static char * +canonicalize(char *path) +{ + char *canonical; + + if (path == NULL) { + return NULL; + } + + if (strlen(path) > PATH_MAX) { + fprintf(stderr, "Mount point string too long\n"); + return NULL; + } + + canonical = (char *)malloc (PATH_MAX + 1); + + if (!canonical) { + fprintf(stderr, "Error! Not enough memory!\n"); + return NULL; + } + + if (realpath (path, canonical)) + return canonical; + + strncpy (canonical, path, PATH_MAX); + canonical[PATH_MAX] = '\0'; + return canonical; +} + +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 = canonicalize(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 */ + + /* Trim any trailing slashes */ + while ((strlen(mountpoint) > 1) && + (mountpoint[strlen(mountpoint)-1] == '/')) + { + mountpoint[strlen(mountpoint)-1] = '\0'; + } + + /* 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; +} + |