1 /*
2 * ismounted.c --- Check to see if the filesystem was mounted
3 *
4 * Copyright (C) 1995,1996,1997,1998,1999,2000,2008 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Public
8 * License.
9 * %End-Header%
10 */
11
12 #include "config.h"
13 #include <stdio.h>
14 #if HAVE_UNISTD_H
15 #include <unistd.h>
16 #endif
17 #ifdef HAVE_STDLIB_H
18 #include <stdlib.h>
19 #endif
20 #if HAVE_ERRNO_H
21 #include <errno.h>
22 #endif
23 #include <fcntl.h>
24 #ifdef HAVE_LINUX_FD_H
25 #include <linux/fd.h>
26 #endif
27 #ifdef HAVE_MNTENT_H
28 #include <mntent.h>
29 #endif
30 #include <string.h>
31 #include <sys/stat.h>
32 #include <ctype.h>
33
34 #include "fsck.h"
35
36 /*
37 * ext2fs_check_if_mounted flags
38 */
39 #define MF_MOUNTED 1
40
41 #include "et/com_err.h"
42
43 #ifdef HAVE_SETMNTENT
skip_over_blank(char * cp)44 static char *skip_over_blank(char *cp)
45 {
46 while (*cp && isspace(*cp))
47 cp++;
48 return cp;
49 }
50
skip_over_word(char * cp)51 static char *skip_over_word(char *cp)
52 {
53 while (*cp && !isspace(*cp))
54 cp++;
55 return cp;
56 }
57
parse_word(char ** buf)58 static char *parse_word(char **buf)
59 {
60 char *word, *next;
61
62 word = *buf;
63 if (*word == 0)
64 return 0;
65
66 word = skip_over_blank(word);
67 next = skip_over_word(word);
68 if (*next)
69 *next++ = 0;
70 *buf = next;
71 return word;
72 }
73 #endif
74
75 /*
76 * Helper function which checks a file in /etc/mtab format to see if a
77 * filesystem is mounted. Returns an error if the file doesn't exist
78 * or can't be opened.
79 */
check_mntent_file(const char * mtab_file,const char * file,int * mount_flags)80 static errcode_t check_mntent_file(const char *mtab_file, const char *file,
81 int *mount_flags)
82 {
83 #ifdef HAVE_SETMNTENT
84 struct stat st_buf;
85 errcode_t retval = 0;
86 dev_t file_dev=0, file_rdev=0;
87 ino_t file_ino=0;
88 FILE *f;
89 char buf[1024], *device = 0, *mnt_dir = 0, *cp;
90
91 *mount_flags = 0;
92 if ((f = setmntent (mtab_file, "r")) == NULL)
93 return errno;
94 if (stat(file, &st_buf) == 0) {
95 if (S_ISBLK(st_buf.st_mode)) {
96 #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
97 file_rdev = st_buf.st_rdev;
98 #endif /* __GNU__ */
99 } else {
100 file_dev = st_buf.st_dev;
101 file_ino = st_buf.st_ino;
102 }
103 }
104 while (1) {
105 if (!fgets(buf, sizeof(buf), f)) {
106 device = mnt_dir = 0;
107 break;
108 }
109 buf[sizeof(buf)-1] = 0;
110
111 cp = buf;
112 device = parse_word(&cp);
113 if (!device || *device == '#')
114 return 0; /* Ignore blank lines and comments */
115 mnt_dir = parse_word(&cp);
116
117 if (device[0] != '/')
118 continue;
119
120 if (strcmp(file, device) == 0)
121 break;
122 if (stat(device, &st_buf) == 0) {
123 if (S_ISBLK(st_buf.st_mode)) {
124 #ifndef __GNU__
125 if (file_rdev && (file_rdev == st_buf.st_rdev))
126 break;
127 #endif /* __GNU__ */
128 } else {
129 if (file_dev && ((file_dev == st_buf.st_dev) &&
130 (file_ino == st_buf.st_ino)))
131 break;
132 }
133 }
134 }
135
136 if (mnt_dir == 0) {
137 #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
138 /*
139 * Do an extra check to see if this is the root device. We
140 * can't trust /etc/mtab, and /proc/mounts will only list
141 * /dev/root for the root filesystem. Argh. Instead we
142 * check if the given device has the same major/minor number
143 * as the device that the root directory is on.
144 */
145 if (file_rdev && (stat("/", &st_buf) == 0) &&
146 (st_buf.st_dev == file_rdev))
147 *mount_flags = MF_MOUNTED;
148 #endif /* __GNU__ */
149 goto errout;
150 }
151 #ifndef __GNU__ /* The GNU hurd is deficient; what else is new? */
152 /* Validate the entry in case /etc/mtab is out of date */
153 /*
154 * We need to be paranoid, because some broken distributions
155 * (read: Slackware) don't initialize /etc/mtab before checking
156 * all of the non-root filesystems on the disk.
157 */
158 if (stat(mnt_dir, &st_buf) < 0) {
159 retval = errno;
160 if (retval == ENOENT) {
161 #ifdef DEBUG
162 printf("Bogus entry in %s! (%s does not exist)\n",
163 mtab_file, mnt_dir);
164 #endif /* DEBUG */
165 retval = 0;
166 }
167 goto errout;
168 }
169 if (file_rdev && (st_buf.st_dev != file_rdev)) {
170 #ifdef DEBUG
171 printf("Bogus entry in %s! (%s not mounted on %s)\n",
172 mtab_file, file, mnt_dir);
173 #endif /* DEBUG */
174 goto errout;
175 }
176 #endif /* __GNU__ */
177 *mount_flags = MF_MOUNTED;
178
179 retval = 0;
180 errout:
181 endmntent (f);
182 return retval;
183 #else /* !HAVE_SETMNTENT */
184 return 0;
185 #endif /* HAVE_MNTENT_H */
186 }
187
is_mounted(const char * file)188 int is_mounted(const char *file)
189 {
190 errcode_t retval;
191 int mount_flags = 0;
192
193 #ifdef __linux__
194 retval = check_mntent_file("/proc/mounts", file, &mount_flags);
195 if (retval)
196 return 0;
197 if (mount_flags)
198 return 1;
199 #endif /* __linux__ */
200 retval = check_mntent_file("/etc/mtab", file, &mount_flags);
201 if (retval)
202 return 0;
203 return (mount_flags);
204 }
205
206 #ifdef DEBUG
main(int argc,char ** argv)207 int main(int argc, char **argv)
208 {
209 if (argc < 2) {
210 fprintf(stderr, "Usage: %s device\n", argv[0]);
211 exit(1);
212 }
213
214 if (is_mounted(argv[1]))
215 printf("\t%s is mounted.\n", argv[1]);
216 exit(0);
217 }
218 #endif /* DEBUG */
219