blob: f5f6f31cd9e349f518123d841df7368c74bc2417
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * ismounted.c --- Check to see if the filesystem was mounted |
4 | * |
5 | * Copyright (C) 1995,1996,1997,1998,1999,2000 Theodore Ts'o. |
6 | * |
7 | * %Begin-Header% |
8 | * This file may be redistributed under the terms of the GNU Public |
9 | * License. |
10 | * %End-Header% |
11 | */ |
12 | |
13 | #include <stdio.h> |
14 | #if HAVE_UNISTD_H |
15 | #include <unistd.h> |
16 | #endif |
17 | #if HAVE_ERRNO_H |
18 | #include <errno.h> |
19 | #endif |
20 | #include <fcntl.h> |
21 | #ifdef HAVE_LINUX_FD_H |
22 | #include <linux/fd.h> |
23 | #endif |
24 | #ifdef HAVE_MNTENT_H |
25 | #include <mntent.h> |
26 | #endif |
27 | #ifdef HAVE_GETMNTINFO |
28 | #include <paths.h> |
29 | #include <sys/param.h> |
30 | #include <sys/mount.h> |
31 | #endif /* HAVE_GETMNTINFO */ |
32 | #include <string.h> |
33 | #include <sys/stat.h> |
34 | |
35 | #include "ext2_fs.h" |
36 | #include "ext2fs.h" |
37 | |
38 | #ifdef HAVE_MNTENT_H |
39 | /* |
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 |
42 | * or can't be opened. |
43 | */ |
44 | static errcode_t check_mntent_file(const char *mtab_file, const char *file, |
45 | int *mount_flags, char *mtpt, int mtlen) |
46 | { |
47 | struct mntent *mnt; |
48 | struct stat st_buf; |
49 | errcode_t retval = 0; |
50 | dev_t file_dev=0, file_rdev=0; |
51 | ino_t file_ino=0; |
52 | FILE *f; |
53 | int fd; |
54 | |
55 | *mount_flags = 0; |
56 | if ((f = setmntent (mtab_file, "r")) == NULL) |
57 | return 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; |
62 | #endif /* __GNU__ */ |
63 | } else { |
64 | file_dev = st_buf.st_dev; |
65 | file_ino = st_buf.st_ino; |
66 | } |
67 | } |
68 | while ((mnt = getmntent (f)) != NULL) { |
69 | if (strcmp(file, mnt->mnt_fsname) == 0) |
70 | break; |
71 | if (stat(mnt->mnt_fsname, &st_buf) == 0) { |
72 | if (S_ISBLK(st_buf.st_mode)) { |
73 | #ifndef __GNU__ |
74 | if (file_rdev && (file_rdev == st_buf.st_rdev)) |
75 | break; |
76 | #endif /* __GNU__ */ |
77 | } else { |
78 | if (file_dev && ((file_dev == st_buf.st_dev) && |
79 | (file_ino == st_buf.st_ino))) |
80 | break; |
81 | } |
82 | } |
83 | } |
84 | |
85 | if (mnt == 0) { |
86 | #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */ |
87 | /* |
88 | * Do an extra check to see if this is the root device. We |
89 | * can't trust /etc/mtab, and /proc/mounts will only list |
90 | * /dev/root for the root filesystem. Argh. Instead we |
91 | * check if the given device has the same major/minor number |
92 | * as the device that the root directory is on. |
93 | */ |
94 | if (file_rdev && stat("/", &st_buf) == 0) { |
95 | if (st_buf.st_dev == file_rdev) { |
96 | *mount_flags = EXT2_MF_MOUNTED; |
97 | if (mtpt) |
98 | strncpy(mtpt, "/", mtlen); |
99 | goto is_root; |
100 | } |
101 | } |
102 | #endif /* __GNU__ */ |
103 | goto errout; |
104 | } |
105 | #ifndef __GNU__ /* The GNU hurd is deficient; what else is new? */ |
106 | /* Validate the entry in case /etc/mtab is out of date */ |
107 | /* |
108 | * We need to be paranoid, because some broken distributions |
109 | * (read: Slackware) don't initialize /etc/mtab before checking |
110 | * all of the non-root filesystems on the disk. |
111 | */ |
112 | if (stat(mnt->mnt_dir, &st_buf) < 0) { |
113 | retval = errno; |
114 | if (retval == ENOENT) { |
115 | #ifdef DEBUG |
116 | printf("Bogus entry in %s! (%s does not exist)\n", |
117 | mtab_file, mnt->mnt_dir); |
118 | #endif /* DEBUG */ |
119 | retval = 0; |
120 | } |
121 | goto errout; |
122 | } |
123 | if (file_rdev && (st_buf.st_dev != file_rdev)) { |
124 | #ifdef DEBUG |
125 | printf("Bogus entry in %s! (%s not mounted on %s)\n", |
126 | mtab_file, file, mnt->mnt_dir); |
127 | #endif /* DEBUG */ |
128 | goto errout; |
129 | } |
130 | #endif /* __GNU__ */ |
131 | *mount_flags = EXT2_MF_MOUNTED; |
132 | |
133 | #ifdef MNTOPT_RO |
134 | /* Check to see if the ro option is set */ |
135 | if (hasmntopt(mnt, MNTOPT_RO)) |
136 | *mount_flags |= EXT2_MF_READONLY; |
137 | #endif |
138 | |
139 | if (mtpt) |
140 | strncpy(mtpt, mnt->mnt_dir, mtlen); |
141 | /* |
142 | * Check to see if we're referring to the root filesystem. |
143 | * If so, do a manual check to see if we can open /etc/mtab |
144 | * read/write, since if the root is mounted read/only, the |
145 | * contents of /etc/mtab may not be accurate. |
146 | */ |
147 | if (LONE_CHAR(mnt->mnt_dir, '/')) { |
148 | is_root: |
149 | #define TEST_FILE "/.ismount-test-file" |
150 | *mount_flags |= EXT2_MF_ISROOT; |
151 | fd = open(TEST_FILE, O_RDWR|O_CREAT); |
152 | if (fd < 0) { |
153 | if (errno == EROFS) |
154 | *mount_flags |= EXT2_MF_READONLY; |
155 | } else |
156 | close(fd); |
157 | (void) unlink(TEST_FILE); |
158 | } |
159 | retval = 0; |
160 | errout: |
161 | endmntent (f); |
162 | return retval; |
163 | } |
164 | |
165 | static errcode_t check_mntent(const char *file, int *mount_flags, |
166 | char *mtpt, int mtlen) |
167 | { |
168 | errcode_t retval; |
169 | |
170 | #ifdef DEBUG |
171 | retval = check_mntent_file("/tmp/mtab", file, mount_flags, |
172 | mtpt, mtlen); |
173 | if (retval == 0) |
174 | return 0; |
175 | #endif /* DEBUG */ |
176 | #ifdef __linux__ |
177 | retval = check_mntent_file("/proc/mounts", file, mount_flags, |
178 | mtpt, mtlen); |
179 | if (retval == 0 && (*mount_flags != 0)) |
180 | return 0; |
181 | #endif /* __linux__ */ |
182 | #if defined(MOUNTED) || defined(_PATH_MOUNTED) |
183 | #ifndef MOUNTED |
184 | #define MOUNTED _PATH_MOUNTED |
185 | #endif /* MOUNTED */ |
186 | retval = check_mntent_file(MOUNTED, file, mount_flags, mtpt, mtlen); |
187 | return retval; |
188 | #else |
189 | *mount_flags = 0; |
190 | return 0; |
191 | #endif /* defined(MOUNTED) || defined(_PATH_MOUNTED) */ |
192 | } |
193 | |
194 | #else |
195 | #if defined(HAVE_GETMNTINFO) |
196 | |
197 | static errcode_t check_getmntinfo(const char *file, int *mount_flags, |
198 | char *mtpt, int mtlen) |
199 | { |
200 | struct statfs *mp; |
201 | int len, n; |
202 | const char *s1; |
203 | char *s2; |
204 | |
205 | n = getmntinfo(&mp, MNT_NOWAIT); |
206 | if (n == 0) |
207 | return errno; |
208 | |
209 | len = sizeof(_PATH_DEV) - 1; |
210 | s1 = file; |
211 | if (strncmp(_PATH_DEV, s1, len) == 0) |
212 | s1 += len; |
213 | |
214 | *mount_flags = 0; |
215 | while (--n >= 0) { |
216 | s2 = mp->f_mntfromname; |
217 | if (strncmp(_PATH_DEV, s2, len) == 0) { |
218 | s2 += len - 1; |
219 | *s2 = 'r'; |
220 | } |
221 | if (strcmp(s1, s2) == 0 || strcmp(s1, &s2[1]) == 0) { |
222 | *mount_flags = EXT2_MF_MOUNTED; |
223 | break; |
224 | } |
225 | ++mp; |
226 | } |
227 | if (mtpt) |
228 | strncpy(mtpt, mp->f_mntonname, mtlen); |
229 | return 0; |
230 | } |
231 | #endif /* HAVE_GETMNTINFO */ |
232 | #endif /* HAVE_MNTENT_H */ |
233 | |
234 | /* |
235 | * Check to see if we're dealing with the swap device. |
236 | */ |
237 | static int is_swap_device(const char *file) |
238 | { |
239 | FILE *f; |
240 | char buf[1024], *cp; |
241 | dev_t file_dev; |
242 | struct stat st_buf; |
243 | int ret = 0; |
244 | |
245 | file_dev = 0; |
246 | #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */ |
247 | if ((stat(file, &st_buf) == 0) && |
248 | S_ISBLK(st_buf.st_mode)) |
249 | file_dev = st_buf.st_rdev; |
250 | #endif /* __GNU__ */ |
251 | |
252 | if (!(f = fopen_for_read("/proc/swaps"))) |
253 | return 0; |
254 | /* Skip the first line */ |
255 | fgets(buf, sizeof(buf), f); |
256 | while (!feof(f)) { |
257 | if (!fgets(buf, sizeof(buf), f)) |
258 | break; |
259 | if ((cp = strchr(buf, ' ')) != NULL) |
260 | *cp = 0; |
261 | if ((cp = strchr(buf, '\t')) != NULL) |
262 | *cp = 0; |
263 | if (strcmp(buf, file) == 0) { |
264 | ret++; |
265 | break; |
266 | } |
267 | #ifndef __GNU__ |
268 | if (file_dev && (stat(buf, &st_buf) == 0) && |
269 | S_ISBLK(st_buf.st_mode) && |
270 | file_dev == st_buf.st_rdev) { |
271 | ret++; |
272 | break; |
273 | } |
274 | #endif /* __GNU__ */ |
275 | } |
276 | fclose(f); |
277 | return ret; |
278 | } |
279 | |
280 | |
281 | /* |
282 | * ext2fs_check_mount_point() returns 1 if the device is mounted, 0 |
283 | * otherwise. If mtpt is non-NULL, the directory where the device is |
284 | * mounted is copied to where mtpt is pointing, up to mtlen |
285 | * characters. |
286 | */ |
287 | #ifdef __TURBOC__ |
288 | # pragma argsused |
289 | #endif |
290 | errcode_t ext2fs_check_mount_point(const char *device, int *mount_flags, |
291 | char *mtpt, int mtlen) |
292 | { |
293 | if (is_swap_device(device)) { |
294 | *mount_flags = EXT2_MF_MOUNTED | EXT2_MF_SWAP; |
295 | strncpy(mtpt, "<swap>", mtlen); |
296 | return 0; |
297 | } |
298 | #ifdef HAVE_MNTENT_H |
299 | return check_mntent(device, mount_flags, mtpt, mtlen); |
300 | #else |
301 | #ifdef HAVE_GETMNTINFO |
302 | return check_getmntinfo(device, mount_flags, mtpt, mtlen); |
303 | #else |
304 | #ifdef __GNUC__ |
305 | #warning "Can't use getmntent or getmntinfo to check for mounted filesystems!" |
306 | #endif |
307 | *mount_flags = 0; |
308 | return 0; |
309 | #endif /* HAVE_GETMNTINFO */ |
310 | #endif /* HAVE_MNTENT_H */ |
311 | } |
312 | |
313 | /* |
314 | * ext2fs_check_if_mounted() sets the mount_flags EXT2_MF_MOUNTED, |
315 | * EXT2_MF_READONLY, and EXT2_MF_ROOT |
316 | * |
317 | */ |
318 | errcode_t ext2fs_check_if_mounted(const char *file, int *mount_flags) |
319 | { |
320 | return ext2fs_check_mount_point(file, mount_flags, NULL, 0); |
321 | } |
322 | |
323 | #ifdef DEBUG |
324 | int main(int argc, char **argv) |
325 | { |
326 | int retval, mount_flags; |
327 | char mntpt[80]; |
328 | |
329 | if (argc < 2) { |
330 | fprintf(stderr, "Usage: %s device\n", argv[0]); |
331 | exit(1); |
332 | } |
333 | |
334 | mntpt[0] = 0; |
335 | retval = ext2fs_check_mount_point(argv[1], &mount_flags, |
336 | mntpt, sizeof(mntpt)); |
337 | if (retval) { |
338 | com_err(argv[0], retval, |
339 | "while calling ext2fs_check_if_mounted"); |
340 | exit(1); |
341 | } |
342 | printf("Device %s reports flags %02x\n", argv[1], mount_flags); |
343 | if (mount_flags & EXT2_MF_BUSY) |
344 | printf("\t%s is apparently in use.\n", argv[1]); |
345 | if (mount_flags & EXT2_MF_MOUNTED) |
346 | printf("\t%s is mounted.\n", argv[1]); |
347 | if (mount_flags & EXT2_MF_SWAP) |
348 | printf("\t%s is a swap device.\n", argv[1]); |
349 | if (mount_flags & EXT2_MF_READONLY) |
350 | printf("\t%s is read-only.\n", argv[1]); |
351 | if (mount_flags & EXT2_MF_ISROOT) |
352 | printf("\t%s is the root filesystem.\n", argv[1]); |
353 | if (mntpt[0]) |
354 | printf("\t%s is mounted on %s.\n", argv[1], mntpt); |
355 | exit(0); |
356 | } |
357 | #endif /* DEBUG */ |
358 |