src/test/test-mountpoint-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <sched.h>
   4 #include <sys/mount.h>
   5 #include <unistd.h>
   6
   7 #include "alloc-util.h"
   8 #include "constants.h"
   9 #include "fd-util.h"
  10 #include "fileio.h"
  11 #include "hashmap.h"
  12 #include "log.h"
  13 #include "mountpoint-util.h"
  14 #include "path-util.h"
  15 #include "rm-rf.h"
  16 #include "string-util.h"
  17 #include "tests.h"
  18 #include "tmpfile-util.h"
  19
  20 static void test_mount_propagation_flag_one(const char *name, int ret, unsigned long expected) {
  21         unsigned long flags;
  22
  23         log_info("/* %s(%s) */", __func__, strnull(name));
  24
  25         assert_se(mount_propagation_flag_from_string(name, &flags) == ret);
  26
  27         if (ret >= 0) {
  28                 const char *c;
  29
  30                 assert_se(flags == expected);
  31
  32                 c = mount_propagation_flag_to_string(flags);
  33                 if (isempty(name))
  34                         assert_se(isempty(c));
  35                 else
  36                         assert_se(streq(c, name));
  37         }
  38 }
  39
  40 TEST(mount_propagation_flag) {
  41         test_mount_propagation_flag_one("shared", 0, MS_SHARED);
  42         test_mount_propagation_flag_one("slave", 0, MS_SLAVE);
  43         test_mount_propagation_flag_one("private", 0, MS_PRIVATE);
  44         test_mount_propagation_flag_one(NULL, 0, 0);
  45         test_mount_propagation_flag_one("", 0, 0);
  46         test_mount_propagation_flag_one("xxxx", -EINVAL, 0);
  47         test_mount_propagation_flag_one(" ", -EINVAL, 0);
  48 }
  49
  50 TEST(mnt_id) {
  51         _cleanup_fclose_ FILE *f = NULL;
  52         _cleanup_hashmap_free_free_ Hashmap *h = NULL;
  53         char *p;
  54         void *k;
  55         int r;
  56
  57         assert_se(f = fopen("/proc/self/mountinfo", "re"));
  58         assert_se(h = hashmap_new(&trivial_hash_ops));
  59
  60         for (;;) {
  61                 _cleanup_free_ char *line = NULL, *path = NULL;
  62                 int mnt_id;
  63
  64                 r = read_line(f, LONG_LINE_MAX, &line);
  65                 if (r == 0)
  66                         break;
  67                 assert_se(r > 0);
  68
  69                 assert_se(sscanf(line, "%i %*s %*s %*s %ms", &mnt_id, &path) == 2);
  70 #if HAS_FEATURE_MEMORY_SANITIZER
  71                 /* We don't know the length of the string, so we need to unpoison it one char at a time */
  72                 for (const char *c = path; ;c++) {
  73                         msan_unpoison(c, 1);
  74                         if (!*c)
  75                                 break;
  76                 }
  77 #endif
  78                 log_debug("mountinfo: %s → %i", path, mnt_id);
  79
  80                 assert_se(hashmap_put(h, INT_TO_PTR(mnt_id), path) >= 0);
  81                 path = NULL;
  82         }
  83
  84         HASHMAP_FOREACH_KEY(p, k, h) {
  85                 int mnt_id = PTR_TO_INT(k), mnt_id2;
  86                 const char *q;
  87
  88                 r = path_get_mnt_id(p, &mnt_id2);
  89                 if (r < 0) {
  90                         log_debug_errno(r, "Failed to get the mnt id of %s: %m", p);
  91                         continue;
  92                 }
  93
  94                 if (mnt_id == mnt_id2) {
  95                         log_debug("mnt ids of %s is %i.", p, mnt_id);
  96                         continue;
  97                 } else
  98                         log_debug("mnt ids of %s are %i (from /proc/self/mountinfo), %i (from path_get_mnt_id()).", p, mnt_id, mnt_id2);
  99
 100                 /* The ids don't match? This can easily happen e.g. running with "unshare --mount-proc".
 101                  * See #11505. */
 102                 assert_se(q = hashmap_get(h, INT_TO_PTR(mnt_id2)));
 103
 104                 assert_se((r = path_is_mount_point(p, NULL, 0)) >= 0);
 105                 if (r == 0) {
 106                         /* If the path is not a mount point anymore, then it must be a sub directory of
 107                          * the path corresponds to mnt_id2. */
 108                         log_debug("The path %s for mnt id %i is not a mount point.", p, mnt_id2);
 109                         assert_se(!isempty(path_startswith(p, q)));
 110                 } else {
 111                         /* If the path is still a mount point, then it must be equivalent to the path
 112                          * corresponds to mnt_id2 */
 113                         log_debug("There are multiple mounts on the same path %s.", p);
 114                         assert_se(path_equal(p, q));
 115                 }
 116         }
 117 }
 118
 119 TEST(path_is_mount_point) {
 120         int fd;
 121         char tmp_dir[] = "/tmp/test-path-is-mount-point-XXXXXX";
 122         _cleanup_free_ char *file1 = NULL, *file2 = NULL, *link1 = NULL, *link2 = NULL;
 123         _cleanup_free_ char *dir1 = NULL, *dir1file = NULL, *dirlink1 = NULL, *dirlink1file = NULL;
 124         _cleanup_free_ char *dir2 = NULL, *dir2file = NULL;
 125
 126         assert_se(path_is_mount_point("/", NULL, AT_SYMLINK_FOLLOW) > 0);
 127         assert_se(path_is_mount_point("/", NULL, 0) > 0);
 128         assert_se(path_is_mount_point("//", NULL, AT_SYMLINK_FOLLOW) > 0);
 129         assert_se(path_is_mount_point("//", NULL, 0) > 0);
 130
 131         assert_se(path_is_mount_point("/proc", NULL, AT_SYMLINK_FOLLOW) > 0);
 132         assert_se(path_is_mount_point("/proc", NULL, 0) > 0);
 133         assert_se(path_is_mount_point("/proc/", NULL, AT_SYMLINK_FOLLOW) > 0);
 134         assert_se(path_is_mount_point("/proc/", NULL, 0) > 0);
 135
 136         assert_se(path_is_mount_point("/proc/1", NULL, AT_SYMLINK_FOLLOW) == 0);
 137         assert_se(path_is_mount_point("/proc/1", NULL, 0) == 0);
 138         assert_se(path_is_mount_point("/proc/1/", NULL, AT_SYMLINK_FOLLOW) == 0);
 139         assert_se(path_is_mount_point("/proc/1/", NULL, 0) == 0);
 140
 141         assert_se(path_is_mount_point("/sys", NULL, AT_SYMLINK_FOLLOW) > 0);
 142         assert_se(path_is_mount_point("/sys", NULL, 0) > 0);
 143         assert_se(path_is_mount_point("/sys/", NULL, AT_SYMLINK_FOLLOW) > 0);
 144         assert_se(path_is_mount_point("/sys/", NULL, 0) > 0);
 145
 146         /* we'll create a hierarchy of different kinds of dir/file/link
 147          * layouts:
 148          *
 149          * <tmp>/file1, <tmp>/file2
 150          * <tmp>/link1 -> file1, <tmp>/link2 -> file2
 151          * <tmp>/dir1/
 152          * <tmp>/dir1/file
 153          * <tmp>/dirlink1 -> dir1
 154          * <tmp>/dirlink1file -> dirlink1/file
 155          * <tmp>/dir2/
 156          * <tmp>/dir2/file
 157          */
 158
 159         /* file mountpoints */
 160         assert_se(mkdtemp(tmp_dir) != NULL);
 161         file1 = path_join(tmp_dir, "file1");
 162         assert_se(file1);
 163         file2 = path_join(tmp_dir, "file2");
 164         assert_se(file2);
 165         fd = open(file1, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
 166         assert_se(fd > 0);
 167         close(fd);
 168         fd = open(file2, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
 169         assert_se(fd > 0);
 170         close(fd);
 171         link1 = path_join(tmp_dir, "link1");
 172         assert_se(link1);
 173         assert_se(symlink("file1", link1) == 0);
 174         link2 = path_join(tmp_dir, "link2");
 175         assert_se(link1);
 176         assert_se(symlink("file2", link2) == 0);
 177
 178         assert_se(path_is_mount_point(file1, NULL, AT_SYMLINK_FOLLOW) == 0);
 179         assert_se(path_is_mount_point(file1, NULL, 0) == 0);
 180         assert_se(path_is_mount_point(link1, NULL, AT_SYMLINK_FOLLOW) == 0);
 181         assert_se(path_is_mount_point(link1, NULL, 0) == 0);
 182
 183         /* directory mountpoints */
 184         dir1 = path_join(tmp_dir, "dir1");
 185         assert_se(dir1);
 186         assert_se(mkdir(dir1, 0755) == 0);
 187         dirlink1 = path_join(tmp_dir, "dirlink1");
 188         assert_se(dirlink1);
 189         assert_se(symlink("dir1", dirlink1) == 0);
 190         dirlink1file = path_join(tmp_dir, "dirlink1file");
 191         assert_se(dirlink1file);
 192         assert_se(symlink("dirlink1/file", dirlink1file) == 0);
 193         dir2 = path_join(tmp_dir, "dir2");
 194         assert_se(dir2);
 195         assert_se(mkdir(dir2, 0755) == 0);
 196
 197         assert_se(path_is_mount_point(dir1, NULL, AT_SYMLINK_FOLLOW) == 0);
 198         assert_se(path_is_mount_point(dir1, NULL, 0) == 0);
 199         assert_se(path_is_mount_point(dirlink1, NULL, AT_SYMLINK_FOLLOW) == 0);
 200         assert_se(path_is_mount_point(dirlink1, NULL, 0) == 0);
 201
 202         /* file in subdirectory mountpoints */
 203         dir1file = path_join(dir1, "file");
 204         assert_se(dir1file);
 205         fd = open(dir1file, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
 206         assert_se(fd > 0);
 207         close(fd);
 208
 209         assert_se(path_is_mount_point(dir1file, NULL, AT_SYMLINK_FOLLOW) == 0);
 210         assert_se(path_is_mount_point(dir1file, NULL, 0) == 0);
 211         assert_se(path_is_mount_point(dirlink1file, NULL, AT_SYMLINK_FOLLOW) == 0);
 212         assert_se(path_is_mount_point(dirlink1file, NULL, 0) == 0);
 213
 214         /* these tests will only work as root */
 215         if (mount(file1, file2, NULL, MS_BIND, NULL) >= 0) {
 216                 int rf, rt, rdf, rdt, rlf, rlt, rl1f, rl1t;
 217                 const char *file2d;
 218
 219                 /* files */
 220                 /* capture results in vars, to avoid dangling mounts on failure */
 221                 log_info("%s: %s", __func__, file2);
 222                 rf = path_is_mount_point(file2, NULL, 0);
 223                 rt = path_is_mount_point(file2, NULL, AT_SYMLINK_FOLLOW);
 224
 225                 file2d = strjoina(file2, "/");
 226                 log_info("%s: %s", __func__, file2d);
 227                 rdf = path_is_mount_point(file2d, NULL, 0);
 228                 rdt = path_is_mount_point(file2d, NULL, AT_SYMLINK_FOLLOW);
 229
 230                 log_info("%s: %s", __func__, link2);
 231                 rlf = path_is_mount_point(link2, NULL, 0);
 232                 rlt = path_is_mount_point(link2, NULL, AT_SYMLINK_FOLLOW);
 233
 234                 assert_se(umount(file2) == 0);
 235
 236                 assert_se(rf == 1);
 237                 assert_se(rt == 1);
 238                 assert_se(rdf == -ENOTDIR);
 239                 assert_se(rdt == -ENOTDIR);
 240                 assert_se(rlf == 0);
 241                 assert_se(rlt == 1);
 242
 243                 /* dirs */
 244                 dir2file = path_join(dir2, "file");
 245                 assert_se(dir2file);
 246                 fd = open(dir2file, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0664);
 247                 assert_se(fd > 0);
 248                 close(fd);
 249
 250                 assert_se(mount(dir2, dir1, NULL, MS_BIND, NULL) >= 0);
 251
 252                 log_info("%s: %s", __func__, dir1);
 253                 rf = path_is_mount_point(dir1, NULL, 0);
 254                 rt = path_is_mount_point(dir1, NULL, AT_SYMLINK_FOLLOW);
 255                 log_info("%s: %s", __func__, dirlink1);
 256                 rlf = path_is_mount_point(dirlink1, NULL, 0);
 257                 rlt = path_is_mount_point(dirlink1, NULL, AT_SYMLINK_FOLLOW);
 258                 log_info("%s: %s", __func__, dirlink1file);
 259                 /* its parent is a mount point, but not /file itself */
 260                 rl1f = path_is_mount_point(dirlink1file, NULL, 0);
 261                 rl1t = path_is_mount_point(dirlink1file, NULL, AT_SYMLINK_FOLLOW);
 262
 263                 assert_se(umount(dir1) == 0);
 264
 265                 assert_se(rf == 1);
 266                 assert_se(rt == 1);
 267                 assert_se(rlf == 0);
 268                 assert_se(rlt == 1);
 269                 assert_se(rl1f == 0);
 270                 assert_se(rl1t == 0);
 271
 272         } else
 273                 log_info("Skipping bind mount file test");
 274
 275         assert_se(rm_rf(tmp_dir, REMOVE_ROOT|REMOVE_PHYSICAL) == 0);
 276 }
 277
 278 TEST(fd_is_mount_point) {
 279         _cleanup_close_ int fd = -1;
 280         int r;
 281
 282         fd = open("/", O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOCTTY);
 283         assert_se(fd >= 0);
 284
 285         /* Not allowed, since "/" is a path, not a plain filename */
 286         assert_se(fd_is_mount_point(fd, "/", 0) == -EINVAL);
 287         assert_se(fd_is_mount_point(fd, ".", 0) == -EINVAL);
 288         assert_se(fd_is_mount_point(fd, "./", 0) == -EINVAL);
 289         assert_se(fd_is_mount_point(fd, "..", 0) == -EINVAL);
 290         assert_se(fd_is_mount_point(fd, "../", 0) == -EINVAL);
 291         assert_se(fd_is_mount_point(fd, "", 0) == -EINVAL);
 292         assert_se(fd_is_mount_point(fd, "/proc", 0) == -EINVAL);
 293         assert_se(fd_is_mount_point(fd, "/proc/", 0) == -EINVAL);
 294         assert_se(fd_is_mount_point(fd, "proc/sys", 0) == -EINVAL);
 295         assert_se(fd_is_mount_point(fd, "proc/sys/", 0) == -EINVAL);
 296
 297         /* This one definitely is a mount point */
 298         assert_se(fd_is_mount_point(fd, "proc", 0) > 0);
 299         assert_se(fd_is_mount_point(fd, "proc/", 0) > 0);
 300
 301         /* /root's entire reason for being is to be on the root file system (i.e. not in /home/ which
 302          * might be split off), so that the user can always log in, so it cannot be a mount point unless
 303          * the system is borked. Let's allow for it to be missing though. */
 304         assert_se(IN_SET(fd_is_mount_point(fd, "root", 0), -ENOENT, 0));
 305         assert_se(IN_SET(fd_is_mount_point(fd, "root/", 0), -ENOENT, 0));
 306
 307         safe_close(fd);
 308         fd = open("/proc", O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOCTTY);
 309         assert_se(fd >= 0);
 310
 311         assert_se(fd_is_mount_point(fd, NULL, 0) > 0);
 312         assert_se(fd_is_mount_point(fd, "", 0) == -EINVAL);
 313         assert_se(fd_is_mount_point(fd, "version", 0) == 0);
 314
 315         safe_close(fd);
 316         fd = open("/proc/version", O_RDONLY|O_CLOEXEC|O_NOCTTY);
 317         assert_se(fd >= 0);
 318
 319         r = fd_is_mount_point(fd, NULL, 0);
 320         assert_se(IN_SET(r, 0, -ENOTDIR)); /* on old kernels we can't determine if regular files are mount points if we have no directory fd */
 321         assert_se(fd_is_mount_point(fd, "", 0) == -EINVAL);
 322 }
 323
 324 static int intro(void) {
 325         /* let's move into our own mount namespace with all propagation from the host turned off, so
 326          * that /proc/self/mountinfo is static and constant for the whole time our test runs. */
 327
 328         if (unshare(CLONE_NEWNS) < 0) {
 329                 if (!ERRNO_IS_PRIVILEGE(errno))
 330                         return log_error_errno(errno, "Failed to detach mount namespace: %m");
 331
 332                 log_notice("Lacking privilege to create separate mount namespace, proceeding in originating mount namespace.");
 333         } else
 334                 assert_se(mount(NULL, "/", NULL, MS_PRIVATE | MS_REC, NULL) >= 0);
 335
 336         return EXIT_SUCCESS;
 337 }
 338
 339 DEFINE_TEST_MAIN_WITH_INTRO(LOG_DEBUG, intro);