summaryrefslogtreecommitdiffstats
path: root/src/test/test-mountpoint-util.c
blob: 128daa6de89e7b6b0e4a67bdd480a11481f486c3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <sched.h>
#include <sys/mount.h>
#include <unistd.h>

#include "alloc-util.h"
#include "def.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "hashmap.h"
#include "log.h"
#include "mkdir.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "string-util.h"
#include "tests.h"
#include "tmpfile-util.h"

static void test_mount_propagation_flags(const char *name, int ret, unsigned long expected) {
        long unsigned flags;

        log_info("/* %s(%s) */", __func__, name);

        assert_se(mount_propagation_flags_from_string(name, &flags) == ret);

        if (ret >= 0) {
                const char *c;

                assert_se(flags == expected);

                c = mount_propagation_flags_to_string(flags);
                if (isempty(name))
                        assert_se(isempty(c));
                else
                        assert_se(streq(c, name));
        }
}

static void test_mnt_id(void) {
        _cleanup_fclose_ FILE *f = NULL;
        _cleanup_hashmap_free_free_ Hashmap *h = NULL;
        char *p;
        void *k;
        int r;

        log_info("/* %s */", __func__);

        assert_se(f = fopen("/proc/self/mountinfo", "re"));
        assert_se(h = hashmap_new(&trivial_hash_ops));

        for (;;) {
                _cleanup_free_ char *line = NULL, *path = NULL;
                int mnt_id;

                r = read_line(f, LONG_LINE_MAX, &line);
                if (r == 0)
                        break;
                assert_se(r > 0);

                assert_se(sscanf(line, "%i %*s %*s %*s %ms", &mnt_id, &path) == 2);
#if HAS_FEATURE_MEMORY_SANITIZER
                /* We don't know the length of the string, so we need to unpoison it one char at a time */
                for (const char *c = path; ;c++) {
                        msan_unpoison(c, 1);
                        if (!*c)
                                break;
                }
#endif
                log_debug("mountinfo: %s → %i", path, mnt_id);

                assert_se(hashmap_put(h, INT_TO_PTR(mnt_id), path) >= 0);
                path = NULL;
        }

        HASHMAP_FOREACH_KEY(p, k, h) {
                int mnt_id = PTR_TO_INT(k), mnt_id2;

                r = path_get_mnt_id(p, &mnt_id2);
                if (r < 0) {
                        log_debug_errno(r, "Failed to get the mnt id of %s: %m\n", p);
                        continue;
                }

                if (mnt_id == mnt_id2) {
                        log_debug("mnt ids of %s is %i\n", p, mnt_id);
                        continue;
                } else
                        log_debug("mnt ids of %s are %i, %i\n", p, mnt_id, mnt_id2);

                /* The ids don't match? If so, then there are two mounts on the same path, let's check if
                 * that's really the case */
                char *t = hashmap_get(h, INT_TO_PTR(mnt_id2));
                log_debug("the other path for mnt id %i is %s\n", mnt_id2, t);
                assert_se(path_equal(p, t));
        }
}

static void test_path_is_mount_point(void) {
        int fd;
        char tmp_dir[] = "/tmp/test-path-is-mount-point-XXXXXX";
        _cleanup_free_ char *file1 = NULL, *file2 = NULL, *link1 = NULL, *link2 = NULL;
        _cleanup_free_ char *dir1 = NULL, *dir1file = NULL, *dirlink1 = NULL, *dirlink1file = NULL;
        _cleanup_free_ char *dir2 = NULL, *dir2file = NULL;

        log_info("/* %s */", __func__);

        assert_se(path_is_mount_point("/", NULL, AT_SYMLINK_FOLLOW) > 0);
        assert_se(path_is_mount_point("/", NULL, 0) > 0);
        assert_se(path_is_mount_point("//", NULL, AT_SYMLINK_FOLLOW) > 0);
        assert_se(path_is_mount_point("//", NULL, 0) > 0);

        assert_se(path_is_mount_point("/proc", NULL, AT_SYMLINK_FOLLOW) > 0);
        assert_se(path_is_mount_point("/proc", NULL, 0) > 0);
        assert_se(path_is_mount_point("/proc/", NULL, AT_SYMLINK_FOLLOW) > 0);
        assert_se(path_is_mount_point("/proc/", NULL, 0) > 0);

        assert_se(path_is_mount_point("/proc/1", NULL, AT_SYMLINK_FOLLOW) == 0);
        assert_se(path_is_mount_point("/proc/1", NULL, 0) == 0);
        assert_se(path_is_mount_point("/proc/1/", NULL, AT_SYMLINK_FOLLOW) == 0);
        assert_se(path_is_mount_point("/proc/1/", NULL, 0) == 0);

        assert_se(path_is_mount_point("/sys", NULL, AT_SYMLINK_FOLLOW) > 0);
        assert_se(path_is_mount_point("/sys", NULL, 0) > 0);
        assert_se(path_is_mount_point("/sys/", NULL, AT_SYMLINK_FOLLOW) > 0);
        assert_se(path_is_mount_point("/sys/", NULL, 0) > 0);

        /* we'll create a hierarchy of different kinds of dir/file/link
         * layouts:
         *
         * <tmp>/file1, <tmp>/file2
         * <tmp>/link1 -> file1, <tmp>/link2 -> file2
         * <tmp>/dir1/
         * <tmp>/dir1/file
         * <tmp>/dirlink1 -> dir1
         * <tmp>/dirlink1file -> dirlink1/file
         * <tmp>/dir2/
         * <tmp>/dir2/file
         */

        /* file mountpoints */
        assert_se(mkdtemp(tmp_dir) != NULL);
        file1 = path_join(tmp_dir, "file1");
        assert_se(file1);
        file2 = path_join(tmp_dir, "file2");
        assert_se(file2);
        fd = open(file1, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
        assert_se(fd > 0);
        close(fd);
        fd = open(file2, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
        assert_se(fd > 0);
        close(fd);
        link1 = path_join(tmp_dir, "link1");
        assert_se(link1);
        assert_se(symlink("file1", link1) == 0);
        link2 = path_join(tmp_dir, "link2");
        assert_se(link1);
        assert_se(symlink("file2", link2) == 0);

        assert_se(path_is_mount_point(file1, NULL, AT_SYMLINK_FOLLOW) == 0);
        assert_se(path_is_mount_point(file1, NULL, 0) == 0);
        assert_se(path_is_mount_point(link1, NULL, AT_SYMLINK_FOLLOW) == 0);
        assert_se(path_is_mount_point(link1, NULL, 0) == 0);

        /* directory mountpoints */
        dir1 = path_join(tmp_dir, "dir1");
        assert_se(dir1);
        assert_se(mkdir(dir1, 0755) == 0);
        dirlink1 = path_join(tmp_dir, "dirlink1");
        assert_se(dirlink1);
        assert_se(symlink("dir1", dirlink1) == 0);
        dirlink1file = path_join(tmp_dir, "dirlink1file");
        assert_se(dirlink1file);
        assert_se(symlink("dirlink1/file", dirlink1file) == 0);
        dir2 = path_join(tmp_dir, "dir2");
        assert_se(dir2);
        assert_se(mkdir(dir2, 0755) == 0);

        assert_se(path_is_mount_point(dir1, NULL, AT_SYMLINK_FOLLOW) == 0);
        assert_se(path_is_mount_point(dir1, NULL, 0) == 0);
        assert_se(path_is_mount_point(dirlink1, NULL, AT_SYMLINK_FOLLOW) == 0);
        assert_se(path_is_mount_point(dirlink1, NULL, 0) == 0);

        /* file in subdirectory mountpoints */
        dir1file = path_join(dir1, "file");
        assert_se(dir1file);
        fd = open(dir1file, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
        assert_se(fd > 0);
        close(fd);

        assert_se(path_is_mount_point(dir1file, NULL, AT_SYMLINK_FOLLOW) == 0);
        assert_se(path_is_mount_point(dir1file, NULL, 0) == 0);
        assert_se(path_is_mount_point(dirlink1file, NULL, AT_SYMLINK_FOLLOW) == 0);
        assert_se(path_is_mount_point(dirlink1file, NULL, 0) == 0);

        /* these tests will only work as root */
        if (mount(file1, file2, NULL, MS_BIND, NULL) >= 0) {
                int rf, rt, rdf, rdt, rlf, rlt, rl1f, rl1t;
                const char *file2d;

                /* files */
                /* capture results in vars, to avoid dangling mounts on failure */
                log_info("%s: %s", __func__, file2);
                rf = path_is_mount_point(file2, NULL, 0);
                rt = path_is_mount_point(file2, NULL, AT_SYMLINK_FOLLOW);

                file2d = strjoina(file2, "/");
                log_info("%s: %s", __func__, file2d);
                rdf = path_is_mount_point(file2d, NULL, 0);
                rdt = path_is_mount_point(file2d, NULL, AT_SYMLINK_FOLLOW);

                log_info("%s: %s", __func__, link2);
                rlf = path_is_mount_point(link2, NULL, 0);
                rlt = path_is_mount_point(link2, NULL, AT_SYMLINK_FOLLOW);

                assert_se(umount(file2) == 0);

                assert_se(rf == 1);
                assert_se(rt == 1);
                assert_se(rdf == -ENOTDIR);
                assert_se(rdt == -ENOTDIR);
                assert_se(rlf == 0);
                assert_se(rlt == 1);

                /* dirs */
                dir2file = path_join(dir2, "file");
                assert_se(dir2file);
                fd = open(dir2file, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
                assert_se(fd > 0);
                close(fd);

                assert_se(mount(dir2, dir1, NULL, MS_BIND, NULL) >= 0);

                log_info("%s: %s", __func__, dir1);
                rf = path_is_mount_point(dir1, NULL, 0);
                rt = path_is_mount_point(dir1, NULL, AT_SYMLINK_FOLLOW);
                log_info("%s: %s", __func__, dirlink1);
                rlf = path_is_mount_point(dirlink1, NULL, 0);
                rlt = path_is_mount_point(dirlink1, NULL, AT_SYMLINK_FOLLOW);
                log_info("%s: %s", __func__, dirlink1file);
                /* its parent is a mount point, but not /file itself */
                rl1f = path_is_mount_point(dirlink1file, NULL, 0);
                rl1t = path_is_mount_point(dirlink1file, NULL, AT_SYMLINK_FOLLOW);

                assert_se(umount(dir1) == 0);

                assert_se(rf == 1);
                assert_se(rt == 1);
                assert_se(rlf == 0);
                assert_se(rlt == 1);
                assert_se(rl1f == 0);
                assert_se(rl1t == 0);

        } else
                printf("Skipping bind mount file test: %m\n");

        assert_se(rm_rf(tmp_dir, REMOVE_ROOT|REMOVE_PHYSICAL) == 0);
}

static void test_fd_is_mount_point(void) {
        _cleanup_close_ int fd = -1;

        log_info("/* %s */", __func__);

        fd = open("/", O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOCTTY);
        assert_se(fd >= 0);

        /* Not allowed, since "/" is a path, not a plain filename */
        assert_se(fd_is_mount_point(fd, "/", 0) == -EINVAL);
        assert_se(fd_is_mount_point(fd, ".", 0) == -EINVAL);
        assert_se(fd_is_mount_point(fd, "./", 0) == -EINVAL);
        assert_se(fd_is_mount_point(fd, "..", 0) == -EINVAL);
        assert_se(fd_is_mount_point(fd, "../", 0) == -EINVAL);
        assert_se(fd_is_mount_point(fd, "", 0) == -EINVAL);
        assert_se(fd_is_mount_point(fd, "/proc", 0) == -EINVAL);
        assert_se(fd_is_mount_point(fd, "/proc/", 0) == -EINVAL);
        assert_se(fd_is_mount_point(fd, "proc/sys", 0) == -EINVAL);
        assert_se(fd_is_mount_point(fd, "proc/sys/", 0) == -EINVAL);

        /* This one definitely is a mount point */
        assert_se(fd_is_mount_point(fd, "proc", 0) > 0);
        assert_se(fd_is_mount_point(fd, "proc/", 0) > 0);

        /* /root's entire reason for being is to be on the root file system (i.e. not in /home/ which
         * might be split off), so that the user can always log in, so it cannot be a mount point unless
         * the system is borked. Let's allow for it to be missing though. */
        assert_se(IN_SET(fd_is_mount_point(fd, "root", 0), -ENOENT, 0));
        assert_se(IN_SET(fd_is_mount_point(fd, "root/", 0), -ENOENT, 0));
}

static void test_make_mount_point_inode(void) {
        _cleanup_(rm_rf_physical_and_freep) char *d = NULL;
        const char *src_file, *src_dir, *dst_file, *dst_dir;
        struct stat st;

        log_info("/* %s */", __func__);

        assert_se(mkdtemp_malloc(NULL, &d) >= 0);

        src_file = strjoina(d, "/src/file");
        src_dir = strjoina(d, "/src/dir");
        dst_file = strjoina(d, "/dst/file");
        dst_dir = strjoina(d, "/dst/dir");

        assert_se(mkdir_p(src_dir, 0755) >= 0);
        assert_se(mkdir_parents(dst_file, 0755) >= 0);
        assert_se(touch(src_file) >= 0);

        assert_se(make_mount_point_inode_from_path(src_file, dst_file, 0755) >= 0);
        assert_se(make_mount_point_inode_from_path(src_dir, dst_dir, 0755) >= 0);

        assert_se(stat(dst_dir, &st) == 0);
        assert_se(S_ISDIR(st.st_mode));
        assert_se(stat(dst_file, &st) == 0);
        assert_se(S_ISREG(st.st_mode));
        assert_se(!(S_IXUSR & st.st_mode));
        assert_se(!(S_IXGRP & st.st_mode));
        assert_se(!(S_IXOTH & st.st_mode));

        assert_se(unlink(dst_file) == 0);
        assert_se(rmdir(dst_dir) == 0);

        assert_se(stat(src_file, &st) == 0);
        assert_se(make_mount_point_inode_from_stat(&st, dst_file, 0755) >= 0);
        assert_se(stat(src_dir, &st) == 0);
        assert_se(make_mount_point_inode_from_stat(&st, dst_dir, 0755) >= 0);

        assert_se(stat(dst_dir, &st) == 0);
        assert_se(S_ISDIR(st.st_mode));
        assert_se(stat(dst_file, &st) == 0);
        assert_se(S_ISREG(st.st_mode));
        assert_se(!(S_IXUSR & st.st_mode));
        assert_se(!(S_IXGRP & st.st_mode));
        assert_se(!(S_IXOTH & st.st_mode));
}

int main(int argc, char *argv[]) {
        test_setup_logging(LOG_DEBUG);

        /* let's move into our own mount namespace with all propagation from the host turned off, so that
         * /proc/self/mountinfo is static and constant for the whole time our test runs. */
        if (unshare(CLONE_NEWNS) < 0) {
                if (!ERRNO_IS_PRIVILEGE(errno))
                        return log_error_errno(errno, "Failed to detach mount namespace: %m");

                log_notice("Lacking privilege to create separate mount namespace, proceeding in originating mount namespace.");
        } else
                assert_se(mount(NULL, "/", NULL, MS_PRIVATE | MS_REC, NULL) >= 0);

        test_mount_propagation_flags("shared", 0, MS_SHARED);
        test_mount_propagation_flags("slave", 0, MS_SLAVE);
        test_mount_propagation_flags("private", 0, MS_PRIVATE);
        test_mount_propagation_flags(NULL, 0, 0);
        test_mount_propagation_flags("", 0, 0);
        test_mount_propagation_flags("xxxx", -EINVAL, 0);
        test_mount_propagation_flags(" ", -EINVAL, 0);

        test_mnt_id();
        test_path_is_mount_point();
        test_fd_is_mount_point();
        test_make_mount_point_inode();

        return 0;
}