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fe263da9 TT |
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 | ||
d1154eb4 | 12 | #include "config.h" |
fe263da9 TT |
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> | |
2d328bb7 TT |
32 | #include <ctype.h> |
33 | ||
34 | #include "fsck.h" | |
fe263da9 TT |
35 | |
36 | /* | |
37 | * ext2fs_check_if_mounted flags | |
38 | */ | |
39 | #define MF_MOUNTED 1 | |
40 | ||
41 | #include "et/com_err.h" | |
42 | ||
1d6fd6d0 | 43 | #ifdef HAVE_SETMNTENT |
fe263da9 TT |
44 | static char *skip_over_blank(char *cp) |
45 | { | |
46 | while (*cp && isspace(*cp)) | |
47 | cp++; | |
48 | return cp; | |
49 | } | |
50 | ||
51 | static char *skip_over_word(char *cp) | |
52 | { | |
53 | while (*cp && !isspace(*cp)) | |
54 | cp++; | |
55 | return cp; | |
56 | } | |
57 | ||
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 | } | |
1d6fd6d0 | 73 | #endif |
fe263da9 TT |
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 | */ | |
80 | static errcode_t check_mntent_file(const char *mtab_file, const char *file, | |
81 | int *mount_flags) | |
82 | { | |
b24efa21 | 83 | #ifdef HAVE_SETMNTENT |
fe263da9 TT |
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; | |
fe263da9 TT |
90 | |
91 | *mount_flags = 0; | |
fe263da9 TT |
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; | |
b24efa21 | 183 | #else /* !HAVE_SETMNTENT */ |
2a6b6048 TT |
184 | return 0; |
185 | #endif /* HAVE_MNTENT_H */ | |
fe263da9 TT |
186 | } |
187 | ||
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 | |
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 */ |