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
27 #ifdef HAVE_GETMNTINFO
29 #include <sys/param.h>
30 #include <sys/mount.h>
31 #endif /* HAVE_GETMNTINFO */
40 * Helper function which checks a file in /etc/mtab format to see if a
41 * filesystem is mounted. Returns an error if the file doesn't exist
44 static errcode_t check_mntent_file(const char *mtab_file, const char *file,
45 int *mount_flags, char *mtpt, int mtlen)
50 dev_t file_dev=0, file_rdev=0;
56 if ((f = setmntent (mtab_file, "r")) == NULL)
57 return (errno == ENOENT ? EXT2_NO_MTAB_FILE : errno);
58 if (stat(file, &st_buf) == 0) {
59 if (S_ISBLK(st_buf.st_mode)) {
60 #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
61 file_rdev = st_buf.st_rdev;
64 file_dev = st_buf.st_dev;
65 file_ino = st_buf.st_ino;
68 while ((mnt = getmntent (f)) != NULL) {
69 if (mnt->mnt_fsname[0] != '/')
71 if (strcmp(file, mnt->mnt_fsname) == 0)
73 if (stat(mnt->mnt_fsname, &st_buf) == 0) {
74 if (S_ISBLK(st_buf.st_mode)) {
76 if (file_rdev && (file_rdev == st_buf.st_rdev))
80 if (file_dev && ((file_dev == st_buf.st_dev) &&
81 (file_ino == st_buf.st_ino)))
88 #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
90 * Do an extra check to see if this is the root device. We
91 * can't trust /etc/mtab, and /proc/mounts will only list
92 * /dev/root for the root filesystem. Argh. Instead we
93 * check if the given device has the same major/minor number
94 * as the device that the root directory is on.
96 if (file_rdev && stat("/", &st_buf) == 0) {
97 if (st_buf.st_dev == file_rdev) {
98 *mount_flags = EXT2_MF_MOUNTED;
100 strncpy(mtpt, "/", mtlen);
107 #ifndef __GNU__ /* The GNU hurd is deficient; what else is new? */
108 /* Validate the entry in case /etc/mtab is out of date */
110 * We need to be paranoid, because some broken distributions
111 * (read: Slackware) don't initialize /etc/mtab before checking
112 * all of the non-root filesystems on the disk.
114 if (stat(mnt->mnt_dir, &st_buf) < 0) {
116 if (retval == ENOENT) {
118 printf("Bogus entry in %s! (%s does not exist)\n",
119 mtab_file, mnt->mnt_dir);
125 if (file_rdev && (st_buf.st_dev != file_rdev)) {
127 printf("Bogus entry in %s! (%s not mounted on %s)\n",
128 mtab_file, file, mnt->mnt_dir);
133 *mount_flags = EXT2_MF_MOUNTED;
136 /* Check to see if the ro option is set */
137 if (hasmntopt(mnt, MNTOPT_RO))
138 *mount_flags |= EXT2_MF_READONLY;
142 strncpy(mtpt, mnt->mnt_dir, mtlen);
144 * Check to see if we're referring to the root filesystem.
145 * If so, do a manual check to see if we can open /etc/mtab
146 * read/write, since if the root is mounted read/only, the
147 * contents of /etc/mtab may not be accurate.
149 if (!strcmp(mnt->mnt_dir, "/")) {
151 #define TEST_FILE "/.ismount-test-file"
152 *mount_flags |= EXT2_MF_ISROOT;
153 fd = open(TEST_FILE, O_RDWR|O_CREAT, 0600);
156 *mount_flags |= EXT2_MF_READONLY;
159 (void) unlink(TEST_FILE);
167 static errcode_t check_mntent(const char *file, int *mount_flags,
168 char *mtpt, int mtlen)
173 retval = check_mntent_file("/tmp/mtab", file, mount_flags,
179 retval = check_mntent_file("/proc/mounts", file, mount_flags,
181 if (retval == 0 && (*mount_flags != 0))
183 #endif /* __linux__ */
184 #if defined(MOUNTED) || defined(_PATH_MOUNTED)
186 #define MOUNTED _PATH_MOUNTED
188 retval = check_mntent_file(MOUNTED, file, mount_flags, mtpt, mtlen);
193 #endif /* defined(MOUNTED) || defined(_PATH_MOUNTED) */
197 #if defined(HAVE_GETMNTINFO)
199 static errcode_t check_getmntinfo(const char *file, int *mount_flags,
200 char *mtpt, int mtlen)
207 n = getmntinfo(&mp, MNT_NOWAIT);
211 len = sizeof(_PATH_DEV) - 1;
213 if (strncmp(_PATH_DEV, s1, len) == 0)
218 s2 = mp->f_mntfromname;
219 if (strncmp(_PATH_DEV, s2, len) == 0) {
223 if (strcmp(s1, s2) == 0 || strcmp(s1, &s2[1]) == 0) {
224 *mount_flags = EXT2_MF_MOUNTED;
230 strncpy(mtpt, mp->f_mntonname, mtlen);
233 #endif /* HAVE_GETMNTINFO */
234 #endif /* HAVE_MNTENT_H */
237 * Check to see if we're dealing with the swap device.
239 static int is_swap_device(const char *file)
248 #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
249 if ((stat(file, &st_buf) == 0) &&
250 S_ISBLK(st_buf.st_mode))
251 file_dev = st_buf.st_rdev;
254 if (!(f = fopen("/proc/swaps", "r")))
256 /* Skip the first line */
257 if (!fgets(buf, sizeof(buf), f))
259 if (*buf && strncmp(buf, "Filename\t", 9))
260 /* Linux <=2.6.19 contained a bug in the /proc/swaps
261 * code where the header would not be displayed
263 goto valid_first_line;
265 while (fgets(buf, sizeof(buf), f)) {
267 if ((cp = strchr(buf, ' ')) != NULL)
269 if ((cp = strchr(buf, '\t')) != NULL)
271 if (strcmp(buf, file) == 0) {
276 if (file_dev && (stat(buf, &st_buf) == 0) &&
277 S_ISBLK(st_buf.st_mode) &&
278 file_dev == st_buf.st_rdev) {
292 * ext2fs_check_mount_point() fills determines if the device is
293 * mounted or otherwise busy, and fills in mount_flags with one or
294 * more of the following flags: EXT2_MF_MOUNTED, EXT2_MF_ISROOT,
295 * EXT2_MF_READONLY, EXT2_MF_SWAP, and EXT2_MF_BUSY. If mtpt is
296 * non-NULL, the directory where the device is mounted is copied to
297 * where mtpt is pointing, up to mtlen characters.
302 errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags,
303 char *mtpt, int mtlen)
306 errcode_t retval = 0;
309 if (is_swap_device(device)) {
310 *mount_flags = EXT2_MF_MOUNTED | EXT2_MF_SWAP;
311 strncpy(mtpt, "<swap>", mtlen);
314 retval = check_mntent(device, mount_flags, mtpt, mtlen);
316 #ifdef HAVE_GETMNTINFO
317 retval = check_getmntinfo(device, mount_flags, mtpt, mtlen);
320 #warning "Can't use getmntent or getmntinfo to check for mounted filesystems!"
323 #endif /* HAVE_GETMNTINFO */
324 #endif /* HAVE_MNTENT_H */
329 #ifdef __linux__ /* This only works on Linux 2.6+ systems */
330 if ((stat(device, &st_buf) != 0) ||
331 !S_ISBLK(st_buf.st_mode))
333 fd = open(device, O_RDONLY | O_EXCL);
336 *mount_flags |= EXT2_MF_BUSY;
345 * ext2fs_check_if_mounted() sets the mount_flags EXT2_MF_MOUNTED,
346 * EXT2_MF_READONLY, and EXT2_MF_ROOT
349 errcode_t ext2fs_check_if_mounted(const char *file, int *mount_flags)
351 return ext2fs_check_mount_point(file, mount_flags, NULL, 0);
355 int main(int argc, char **argv)
357 int retval, mount_flags;
361 fprintf(stderr, "Usage: %s device\n", argv[0]);
365 add_error_table(&et_ext2_error_table);
367 retval = ext2fs_check_mount_point(argv[1], &mount_flags,
368 mntpt, sizeof(mntpt));
370 com_err(argv[0], retval,
371 "while calling ext2fs_check_if_mounted");
374 printf("Device %s reports flags %02x\n", argv[1], mount_flags);
375 if (mount_flags & EXT2_MF_BUSY)
376 printf("\t%s is apparently in use.\n", argv[1]);
377 if (mount_flags & EXT2_MF_MOUNTED)
378 printf("\t%s is mounted.\n", argv[1]);
379 if (mount_flags & EXT2_MF_SWAP)
380 printf("\t%s is a swap device.\n", argv[1]);
381 if (mount_flags & EXT2_MF_READONLY)
382 printf("\t%s is read-only.\n", argv[1]);
383 if (mount_flags & EXT2_MF_ISROOT)
384 printf("\t%s is the root filesystem.\n", argv[1]);
386 printf("\t%s is mounted on %s.\n", argv[1], mntpt);