1 /*
2  * plausible.c --- Figure out if a pathname is ext* or something else.
3  *
4  * Copyright 2014, Oracle, Inc.
5  *
6  * Some parts are:
7  * Copyright 1995, 1996, 1997, 1998, 1999, 2000 by Theodore Ts'o.
8  *
9  * %Begin-Header%
10  * This file may be redistributed under the terms of the GNU Public
11  * License.
12  * %End-Header%
13  */
14 
15 #ifndef _LARGEFILE_SOURCE
16 #define _LARGEFILE_SOURCE
17 #endif
18 #ifndef _LARGEFILE64_SOURCE
19 #define _LARGEFILE64_SOURCE
20 #endif
21 
22 #include "config.h"
23 #include <fcntl.h>
24 #include <time.h>
25 #include <sys/types.h>
26 #ifdef HAVE_SYS_STAT_H
27 #include <sys/stat.h>
28 #endif
29 #ifdef HAVE_UNISTD_H
30 #include <unistd.h>
31 #endif
32 #ifdef HAVE_MAGIC_H
33 #include <magic.h>
34 #endif
35 #include "plausible.h"
36 #include "ext2fs/ext2fs.h"
37 #include "nls-enable.h"
38 #include "blkid/blkid.h"
39 
40 #ifdef HAVE_MAGIC_H
41 static magic_t (*dl_magic_open)(int);
42 static const char *(*dl_magic_file)(magic_t, const char *);
43 static int (*dl_magic_load)(magic_t, const char *);
44 static void (*dl_magic_close)(magic_t);
45 
46 #ifdef HAVE_DLOPEN
47 #include <dlfcn.h>
48 
49 static void *magic_handle;
50 
51 static int magic_library_available(void)
52 {
53 	if (!magic_handle) {
54 		magic_handle = dlopen("libmagic.so.1", RTLD_NOW);
55 		if (!magic_handle)
56 			return 0;
57 
58 		dl_magic_open = (magic_t (*)(int))
59 			dlsym(magic_handle, "magic_open");
60 		dl_magic_file = (const char *(*)(magic_t, const char *))
61 			dlsym(magic_handle, "magic_file");
62 		dl_magic_load = (int (*)(magic_t, const char *))
63 			dlsym(magic_handle, "magic_load");
64 		dl_magic_close = (void (*)(magic_t))
65 			dlsym(magic_handle, "magic_close");
66 	}
67 
68 	if (!dl_magic_open || !dl_magic_file ||
69 	    !dl_magic_load || !dl_magic_close)
70 		return 0;
71 	return 1;
72 }
73 #else
74 static int magic_library_available(void)
75 {
76 	dl_magic_open = magic_open;
77 	dl_magic_file = magic_file;
78 	dl_magic_load = magic_load;
79 	dl_magic_close = magic_close;
80 
81 	return 1;
82 }
83 #endif
84 #endif
85 
86 static void print_ext2_info(const char *device)
87 
88 {
89 	struct ext2_super_block	*sb;
90 	ext2_filsys		fs;
91 	errcode_t		retval;
92 	time_t			tm;
93 	char			buf[80];
94 
95 	retval = ext2fs_open2(device, 0, EXT2_FLAG_64BITS, 0, 0,
96 			      unix_io_manager, &fs);
97 	if (retval)
98 		return;
99 	sb = fs->super;
100 
101 	if (sb->s_mtime) {
102 		tm = sb->s_mtime;
103 		if (sb->s_last_mounted[0]) {
104 			memset(buf, 0, sizeof(buf));
105 			strncpy(buf, sb->s_last_mounted,
106 				sizeof(sb->s_last_mounted));
107 			printf(_("\tlast mounted on %s on %s"), buf,
108 			       ctime(&tm));
109 		} else
110 			printf(_("\tlast mounted on %s"), ctime(&tm));
111 	} else if (sb->s_mkfs_time) {
112 		tm = sb->s_mkfs_time;
113 		printf(_("\tcreated on %s"), ctime(&tm));
114 	} else if (sb->s_wtime) {
115 		tm = sb->s_wtime;
116 		printf(_("\tlast modified on %s"), ctime(&tm));
117 	}
118 	ext2fs_close_free(&fs);
119 }
120 
121 /*
122  * return 1 if there is no partition table, 0 if a partition table is
123  * detected, and -1 on an error.
124  */
125 #ifdef HAVE_BLKID_PROBE_ENABLE_PARTITIONS
126 static int check_partition_table(const char *device)
127 {
128 	blkid_probe pr;
129 	const char *value;
130 	int ret;
131 
132 	pr = blkid_new_probe_from_filename(device);
133 	if (!pr)
134 		return -1;
135 
136 	ret = blkid_probe_enable_partitions(pr, 1);
137 	if (ret < 0)
138 		goto errout;
139 
140 	ret = blkid_probe_enable_superblocks(pr, 0);
141 	if (ret < 0)
142 		goto errout;
143 
144 	ret = blkid_do_fullprobe(pr);
145 	if (ret < 0)
146 		goto errout;
147 
148 	ret = blkid_probe_lookup_value(pr, "PTTYPE", &value, NULL);
149 	if (ret == 0)
150 		fprintf(stderr, _("Found a %s partition table in %s\n"),
151 			value, device);
152 	else
153 		ret = 1;
154 
155 errout:
156 	blkid_free_probe(pr);
157 	return ret;
158 }
159 #else
160 static int check_partition_table(const char *device EXT2FS_ATTR((unused)))
161 {
162 	return -1;
163 }
164 #endif
165 
166 /*
167  * return 1 if the device looks plausible, creating the file if necessary
168  */
169 int check_plausibility(const char *device, int flags, int *ret_is_dev)
170 {
171 	int fd, ret, is_dev = 0;
172 	ext2fs_struct_stat s;
173 	int fl = O_RDONLY;
174 	blkid_cache cache = NULL;
175 	char *fs_type = NULL;
176 	char *fs_label = NULL;
177 
178 	fd = ext2fs_open_file(device, fl, 0666);
179 	if ((fd < 0) && (errno == ENOENT) && (flags & NO_SIZE)) {
180 		fprintf(stderr, _("The file %s does not exist and no "
181 				  "size was specified.\n"), device);
182 		exit(1);
183 	}
184 	if ((fd < 0) && (errno == ENOENT) && (flags & CREATE_FILE)) {
185 		fl |= O_CREAT;
186 		fd = ext2fs_open_file(device, fl, 0666);
187 		if (fd >= 0 && (flags & VERBOSE_CREATE))
188 			printf(_("Creating regular file %s\n"), device);
189 	}
190 	if (fd < 0) {
191 		fprintf(stderr, _("Could not open %s: %s\n"),
192 			device, error_message(errno));
193 		if (errno == ENOENT)
194 			fputs(_("\nThe device apparently does not exist; "
195 				"did you specify it correctly?\n"), stderr);
196 		exit(1);
197 	}
198 
199 	if (ext2fs_fstat(fd, &s) < 0) {
200 		perror("stat");
201 		exit(1);
202 	}
203 	close(fd);
204 
205 	if (S_ISBLK(s.st_mode))
206 		is_dev = 1;
207 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
208 	/* On FreeBSD, all disk devices are character specials */
209 	if (S_ISCHR(s.st_mode))
210 		is_dev = 1;
211 #endif
212 	if (ret_is_dev)
213 		*ret_is_dev = is_dev;
214 
215 	if ((flags & CHECK_BLOCK_DEV) && !is_dev) {
216 		printf(_("%s is not a block special device.\n"), device);
217 		return 0;
218 	}
219 
220 	/*
221 	 * Note: we use the older-style blkid API's here because we
222 	 * want as much functionality to be available when using the
223 	 * internal blkid library, when e2fsprogs is compiled for
224 	 * non-Linux systems that will probably not have the libraries
225 	 * from util-linux available.  We only use the newer
226 	 * blkid-probe interfaces to access functionality not
227 	 * available in the original blkid library.
228 	 */
229 	if ((flags & CHECK_FS_EXIST) && blkid_get_cache(&cache, NULL) >= 0) {
230 		fs_type = blkid_get_tag_value(cache, "TYPE", device);
231 		if (fs_type)
232 			fs_label = blkid_get_tag_value(cache, "LABEL", device);
233 		blkid_put_cache(cache);
234 	}
235 
236 	if (fs_type) {
237 		if (fs_label)
238 			printf(_("%s contains a %s file system "
239 				 "labelled '%s'\n"), device, fs_type, fs_label);
240 		else
241 			printf(_("%s contains a %s file system\n"), device,
242 			       fs_type);
243 		if (strncmp(fs_type, "ext", 3) == 0)
244 			print_ext2_info(device);
245 		free(fs_type);
246 		free(fs_label);
247 		return 0;
248 	}
249 
250 #ifdef HAVE_MAGIC_H
251 	if ((flags & CHECK_FS_EXIST) &&
252 	    !getenv("E2FSPROGS_LIBMAGIC_SUPPRESS") &&
253 	    magic_library_available()) {
254 		const char *msg;
255 		magic_t mag;
256 		int has_magic = 0;
257 
258 		mag = dl_magic_open(MAGIC_RAW | MAGIC_SYMLINK | MAGIC_DEVICES |
259 				    MAGIC_ERROR | MAGIC_NO_CHECK_ELF |
260 				    MAGIC_NO_CHECK_COMPRESS);
261 		dl_magic_load(mag, NULL);
262 
263 		msg = dl_magic_file(mag, device);
264 		if (msg && strcmp(msg, "data") && strcmp(msg, "empty")) {
265 			printf(_("%s contains `%s' data\n"), device, msg);
266 			has_magic = 1;
267 		}
268 
269 		dl_magic_close(mag);
270 		return !has_magic;
271 	}
272 #endif
273 
274 	ret = check_partition_table(device);
275 	if (ret >= 0)
276 		return ret;
277 
278 	return 1;
279 }
280 
281