2 * ismounted.c --- Check to see if the filesystem was mounted
4 * Copyright (C) 1995,1996,1997,1998,1999,2000 Theodore Ts'o.
7 * This file may be redistributed under the terms of the GNU Library
8 * General Public License, version 2.
21 #ifdef HAVE_LINUX_FD_H
24 #ifdef HAVE_LINUX_LOOP_H
25 #include <linux/loop.h>
26 #include <sys/ioctl.h>
27 #ifdef HAVE_LINUX_MAJOR_H
28 #include <linux/major.h>
29 #endif /* HAVE_LINUX_MAJOR_H */
30 #endif /* HAVE_LINUX_LOOP_H */
34 #ifdef HAVE_GETMNTINFO
36 #include <sys/param.h>
37 #include <sys/mount.h>
38 #endif /* HAVE_GETMNTINFO */
46 * Check to see if a regular file is mounted.
47 * If /etc/mtab/ is a symlink of /proc/mounts, you will need the following check
48 * because the name in /proc/mounts is a loopback device not a regular file.
50 static int check_loop_mounted(const char *mnt_fsname, dev_t mnt_rdev,
51 dev_t file_dev, ino_t file_ino)
53 #if defined(HAVE_LINUX_LOOP_H) && defined(HAVE_LINUX_MAJOR_H)
54 struct loop_info64 loopinfo;
57 if (major(mnt_rdev) == LOOP_MAJOR) {
58 loop_fd = open(mnt_fsname, O_RDONLY);
62 ret = ioctl(loop_fd, LOOP_GET_STATUS64, &loopinfo);
67 if (file_dev == loopinfo.lo_device &&
68 file_ino == loopinfo.lo_inode)
71 #endif /* defined(HAVE_LINUX_LOOP_H) && defined(HAVE_LINUX_MAJOR_H) */
77 * Helper function which checks a file in /etc/mtab format to see if a
78 * filesystem is mounted. Returns an error if the file doesn't exist
81 static errcode_t check_mntent_file(const char *mtab_file, const char *file,
82 int *mount_flags, char *mtpt, int mtlen)
87 dev_t file_dev=0, file_rdev=0;
93 if ((f = setmntent (mtab_file, "r")) == NULL) {
94 if (errno == ENOENT) {
95 if (getenv("EXT2FS_NO_MTAB_OK"))
98 return EXT2_ET_NO_MTAB_FILE;
102 if (stat(file, &st_buf) == 0) {
103 if (S_ISBLK(st_buf.st_mode)) {
104 #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
105 file_rdev = st_buf.st_rdev;
108 file_dev = st_buf.st_dev;
109 file_ino = st_buf.st_ino;
112 while ((mnt = getmntent (f)) != NULL) {
113 if (mnt->mnt_fsname[0] != '/')
115 if (strcmp(file, mnt->mnt_fsname) == 0)
117 if (stat(mnt->mnt_fsname, &st_buf) == 0) {
118 if (S_ISBLK(st_buf.st_mode)) {
120 if (file_rdev && (file_rdev == st_buf.st_rdev))
122 if (check_loop_mounted(mnt->mnt_fsname,
123 st_buf.st_rdev, file_dev,
128 if (file_dev && ((file_dev == st_buf.st_dev) &&
129 (file_ino == st_buf.st_ino)))
136 #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
138 * Do an extra check to see if this is the root device. We
139 * can't trust /etc/mtab, and /proc/mounts will only list
140 * /dev/root for the root filesystem. Argh. Instead we
141 * check if the given device has the same major/minor number
142 * as the device that the root directory is on.
144 if (file_rdev && stat("/", &st_buf) == 0) {
145 if (st_buf.st_dev == file_rdev) {
146 *mount_flags = EXT2_MF_MOUNTED;
148 strncpy(mtpt, "/", mtlen);
155 #ifndef __GNU__ /* The GNU hurd is deficient; what else is new? */
156 /* Validate the entry in case /etc/mtab is out of date */
158 * We need to be paranoid, because some broken distributions
159 * (read: Slackware) don't initialize /etc/mtab before checking
160 * all of the non-root filesystems on the disk.
162 if (stat(mnt->mnt_dir, &st_buf) < 0) {
164 if (retval == ENOENT) {
166 printf("Bogus entry in %s! (%s does not exist)\n",
167 mtab_file, mnt->mnt_dir);
173 if (file_rdev && (st_buf.st_dev != file_rdev)) {
175 printf("Bogus entry in %s! (%s not mounted on %s)\n",
176 mtab_file, file, mnt->mnt_dir);
181 *mount_flags = EXT2_MF_MOUNTED;
184 /* Check to see if the ro option is set */
185 if (hasmntopt(mnt, MNTOPT_RO))
186 *mount_flags |= EXT2_MF_READONLY;
190 strncpy(mtpt, mnt->mnt_dir, mtlen);
192 * Check to see if we're referring to the root filesystem.
193 * If so, do a manual check to see if we can open /etc/mtab
194 * read/write, since if the root is mounted read/only, the
195 * contents of /etc/mtab may not be accurate.
197 if (!strcmp(mnt->mnt_dir, "/")) {
199 #define TEST_FILE "/.ismount-test-file"
200 *mount_flags |= EXT2_MF_ISROOT;
201 fd = open(TEST_FILE, O_RDWR|O_CREAT, 0600);
204 *mount_flags |= EXT2_MF_READONLY;
207 (void) unlink(TEST_FILE);
215 static errcode_t check_mntent(const char *file, int *mount_flags,
216 char *mtpt, int mtlen)
221 retval = check_mntent_file("/tmp/mtab", file, mount_flags,
227 retval = check_mntent_file("/proc/mounts", file, mount_flags,
229 if (retval == 0 && (*mount_flags != 0))
231 #endif /* __linux__ */
232 #if defined(MOUNTED) || defined(_PATH_MOUNTED)
234 #define MOUNTED _PATH_MOUNTED
236 retval = check_mntent_file(MOUNTED, file, mount_flags, mtpt, mtlen);
241 #endif /* defined(MOUNTED) || defined(_PATH_MOUNTED) */
245 #if defined(HAVE_GETMNTINFO)
247 static errcode_t check_getmntinfo(const char *file, int *mount_flags,
248 char *mtpt, int mtlen)
255 n = getmntinfo(&mp, MNT_NOWAIT);
259 len = sizeof(_PATH_DEV) - 1;
261 if (strncmp(_PATH_DEV, s1, len) == 0)
266 s2 = mp->f_mntfromname;
267 if (strncmp(_PATH_DEV, s2, len) == 0) {
271 if (strcmp(s1, s2) == 0 || strcmp(s1, &s2[1]) == 0) {
272 *mount_flags = EXT2_MF_MOUNTED;
278 strncpy(mtpt, mp->f_mntonname, mtlen);
281 #endif /* HAVE_GETMNTINFO */
282 #endif /* HAVE_SETMNTENT */
285 * Check to see if we're dealing with the swap device.
287 static int is_swap_device(const char *file)
296 #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
297 if ((stat(file, &st_buf) == 0) &&
298 S_ISBLK(st_buf.st_mode))
299 file_dev = st_buf.st_rdev;
302 if (!(f = fopen("/proc/swaps", "r")))
304 /* Skip the first line */
305 if (!fgets(buf, sizeof(buf), f))
307 if (*buf && strncmp(buf, "Filename\t", 9))
308 /* Linux <=2.6.19 contained a bug in the /proc/swaps
309 * code where the header would not be displayed
311 goto valid_first_line;
313 while (fgets(buf, sizeof(buf), f)) {
315 if ((cp = strchr(buf, ' ')) != NULL)
317 if ((cp = strchr(buf, '\t')) != NULL)
319 if (strcmp(buf, file) == 0) {
324 if (file_dev && (stat(buf, &st_buf) == 0) &&
325 S_ISBLK(st_buf.st_mode) &&
326 file_dev == st_buf.st_rdev) {
340 * ext2fs_check_mount_point() fills determines if the device is
341 * mounted or otherwise busy, and fills in mount_flags with one or
342 * more of the following flags: EXT2_MF_MOUNTED, EXT2_MF_ISROOT,
343 * EXT2_MF_READONLY, EXT2_MF_SWAP, and EXT2_MF_BUSY. If mtpt is
344 * non-NULL, the directory where the device is mounted is copied to
345 * where mtpt is pointing, up to mtlen characters.
350 errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags,
351 char *mtpt, int mtlen)
353 errcode_t retval = 0;
355 if (is_swap_device(device)) {
356 *mount_flags = EXT2_MF_MOUNTED | EXT2_MF_SWAP;
357 strncpy(mtpt, "<swap>", mtlen);
359 #ifdef HAVE_SETMNTENT
360 retval = check_mntent(device, mount_flags, mtpt, mtlen);
362 #ifdef HAVE_GETMNTINFO
363 retval = check_getmntinfo(device, mount_flags, mtpt, mtlen);
366 #warning "Can't use getmntent or getmntinfo to check for mounted filesystems!"
369 #endif /* HAVE_GETMNTINFO */
370 #endif /* HAVE_SETMNTENT */
375 #ifdef __linux__ /* This only works on Linux 2.6+ systems */
379 if (stat(device, &st_buf) == 0 && S_ISBLK(st_buf.st_mode)) {
380 int fd = open(device, O_RDONLY | O_EXCL);
384 else if (errno == EBUSY)
385 *mount_flags |= EXT2_MF_BUSY;
394 * ext2fs_check_if_mounted() sets the mount_flags EXT2_MF_MOUNTED,
395 * EXT2_MF_READONLY, and EXT2_MF_ROOT
398 errcode_t ext2fs_check_if_mounted(const char *file, int *mount_flags)
400 return ext2fs_check_mount_point(file, mount_flags, NULL, 0);
404 int main(int argc, char **argv)
406 int retval, mount_flags;
410 fprintf(stderr, "Usage: %s device\n", argv[0]);
414 add_error_table(&et_ext2_error_table);
416 retval = ext2fs_check_mount_point(argv[1], &mount_flags,
417 mntpt, sizeof(mntpt));
419 com_err(argv[0], retval,
420 "while calling ext2fs_check_if_mounted");
423 printf("Device %s reports flags %02x\n", argv[1], mount_flags);
424 if (mount_flags & EXT2_MF_BUSY)
425 printf("\t%s is apparently in use.\n", argv[1]);
426 if (mount_flags & EXT2_MF_MOUNTED)
427 printf("\t%s is mounted.\n", argv[1]);
428 if (mount_flags & EXT2_MF_SWAP)
429 printf("\t%s is a swap device.\n", argv[1]);
430 if (mount_flags & EXT2_MF_READONLY)
431 printf("\t%s is read-only.\n", argv[1]);
432 if (mount_flags & EXT2_MF_ISROOT)
433 printf("\t%s is the root filesystem.\n", argv[1]);
435 printf("\t%s is mounted on %s.\n", argv[1], mntpt);