Merge pull request #23261 from poettering/dir-is-empty

dir_is_empty() fixes

src/basic/stat-util.c

@@ -71,13 +71,10 @@ int is_device_node(const char *path) {
         return !!(S_ISBLK(info.st_mode) || S_ISCHR(info.st_mode));
 }
 
-int dir_is_empty_at(int dir_fd, const char *path) {
+int dir_is_empty_at(int dir_fd, const char *path, bool ignore_hidden_or_backup) {
         _cleanup_close_ int fd = -1;
-        /* Allocate space for at least 3 full dirents, since every dir has at least two entries ("."  +
-         * ".."), and only once we have seen if there's a third we know whether the dir is empty or not. */
-        DEFINE_DIRENT_BUFFER(buffer, 3);
-        struct dirent *de;
-        ssize_t n;
+        struct dirent *buf;
+        size_t m;
 
         if (path) {
                 assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
@@ -99,15 +96,30 @@ int dir_is_empty_at(int dir_fd, const char *path) {
                         return fd;
         }
 
-        n = getdents64(fd, &buffer, sizeof(buffer));
-        if (n < 0)
-                return -errno;
+        /* Allocate space for at least 3 full dirents, since every dir has at least two entries ("."  +
+         * ".."), and only once we have seen if there's a third we know whether the dir is empty or not. If
+         * 'ignore_hidden_or_backup' is true we'll allocate a bit more, since we might skip over a bunch of
+         * entries that we end up ignoring. */
+        m = (ignore_hidden_or_backup ? 16 : 3) * DIRENT_SIZE_MAX;
+        buf = alloca(m);
 
-        msan_unpoison(&buffer, n);
+        for (;;) {
+                struct dirent *de;
+                ssize_t n;
 
-        FOREACH_DIRENT_IN_BUFFER(de, &buffer.de, n)
-                if (!hidden_or_backup_file(de->d_name))
-                        return 0;
+                n = getdents64(fd, buf, m);
+                if (n < 0)
+                        return -errno;
+                if (n == 0)
+                        break;
+
+                assert((size_t) n <= m);
+                msan_unpoison(buf, n);
+
+                FOREACH_DIRENT_IN_BUFFER(de, buf, n)
+                        if (!(ignore_hidden_or_backup ? hidden_or_backup_file(de->d_name) : dot_or_dot_dot(de->d_name)))
+                                return 0;
+        }
 
         return 1;
 }

src/basic/stat-util.h

@@ -17,17 +17,9 @@ int is_dir(const char *path, bool follow);
 int is_dir_fd(int fd);
 int is_device_node(const char *path);
 
-int dir_is_empty_at(int dir_fd, const char *path);
-static inline int dir_is_empty(const char *path) {
-        return dir_is_empty_at(AT_FDCWD, path);
-}
-
-static inline int dir_is_populated(const char *path) {
-        int r;
-        r = dir_is_empty(path);
-        if (r < 0)
-                return r;
-        return !r;
+int dir_is_empty_at(int dir_fd, const char *path, bool ignore_hidden_or_backup);
+static inline int dir_is_empty(const char *path, bool ignore_hidden_or_backup) {
+        return dir_is_empty_at(AT_FDCWD, path, ignore_hidden_or_backup);
 }
 
 bool null_or_empty(struct stat *st) _pure_;

src/boot/bootctl.c

@@ -1639,7 +1639,7 @@ static int are_we_installed(const char *esp_path) {
                 return log_oom();
 
         log_debug("Checking whether %s contains any files…", p);
-        r = dir_is_empty(p);
+        r = dir_is_empty(p, /* ignore_hidden_or_backup= */ false);
         if (r < 0 && r != -ENOENT)
                 return log_error_errno(r, "Failed to check whether %s contains any files: %m", p);
 

src/core/main.c

@@ -1290,7 +1290,7 @@ static void test_usr(void) {
 
         /* Check that /usr is either on the same file system as / or mounted already. */
 
-        if (dir_is_empty("/usr") <= 0)
+        if (dir_is_empty("/usr", /* ignore_hidden_or_backup= */ false) <= 0)
                 return;
 
         log_warning("/usr appears to be on its own filesystem and is not already mounted. This is not a supported setup. "

src/core/manager.c

@@ -976,7 +976,7 @@ int manager_new(LookupScope scope, ManagerTestRunFlags test_run_flags, Manager *
 
         m->taint_usr =
                 !in_initrd() &&
-                dir_is_empty("/usr") > 0;
+                dir_is_empty("/usr", /* ignore_hidden_or_backup= */ false) > 0;
 
         /* Note that we do not set up the notify fd here. We do that after deserialization,
          * since they might have gotten serialized across the reexec. */

src/core/path.c

@@ -213,7 +213,7 @@ static bool path_spec_check_good(PathSpec *s, bool initial, bool from_trigger_no
         case PATH_DIRECTORY_NOT_EMPTY: {
                 int k;
 
-                k = dir_is_empty(s->path);
+                k = dir_is_empty(s->path, /* ignore_hidden_or_backup= */ true);
                 good = !(IN_SET(k, -ENOENT, -ENOTDIR) || k > 0);
                 break;
         }

src/core/unit.c

@@ -4776,7 +4776,7 @@ void unit_warn_if_dir_nonempty(Unit *u, const char* where) {
         if (!unit_log_level_test(u, LOG_NOTICE))
                 return;
 
-        r = dir_is_empty(where);
+        r = dir_is_empty(where, /* ignore_hidden_or_backup= */ false);
         if (r > 0 || r == -ENOTDIR)
                 return;
         if (r < 0) {

src/gpt-auto-generator/gpt-auto-generator.c

@@ -305,7 +305,7 @@ static int path_is_busy(const char *where) {
                 return log_warning_errno(r, "Cannot check if \"%s\" is a mount point: %m", where);
 
         /* not a mountpoint but it contains files */
-        r = dir_is_empty(where);
+        r = dir_is_empty(where, /* ignore_hidden_or_backup= */ false);
         if (r < 0)
                 return log_warning_errno(r, "Cannot check if \"%s\" is empty: %m", where);
         if (r > 0)

src/home/homework-cifs.c

@@ -207,7 +207,7 @@ int home_create_cifs(UserRecord *h, HomeSetup *setup, UserRecord **ret_home) {
         if (r < 0)
                 return r;
 
-        r = dir_is_empty_at(setup->root_fd, NULL);
+        r = dir_is_empty_at(setup->root_fd, NULL, /* ignore_hidden_or_backup= */ false);
         if (r < 0)
                 return log_error_errno(r, "Failed to detect if CIFS directory is empty: %m");
         if (r == 0)

src/home/user-record-util.c

@@ -445,7 +445,7 @@ int user_record_test_home_directory(UserRecord *h) {
         }
 
         /* Otherwise it's not OK */
-        r = dir_is_empty(hd);
+        r = dir_is_empty(hd, /* ignore_hidden_or_backup= */ false);
         if (r < 0)
                 return r;
         if (r == 0)

src/nspawn/nspawn-network.c

@@ -449,7 +449,7 @@ int remove_bridge(const char *bridge_name) {
 
         path = strjoina("/sys/class/net/", bridge_name, "/brif");
 
-        r = dir_is_empty(path);
+        r = dir_is_empty(path, /* ignore_hidden_or_backup= */ false);
         if (r == -ENOENT) /* Already gone? */
                 return 0;
         if (r < 0)

src/nspawn/nspawn.c

@@ -2680,7 +2680,7 @@ static int setup_journal(const char *directory) {
         } else if (access(p, F_OK) < 0)
                 return 0;
 
-        if (dir_is_empty(q) == 0)
+        if (dir_is_empty(q, /* ignore_hidden_or_backup= */ false) == 0)
                 log_warning("%s is not empty, proceeding anyway.", q);
 
         r = userns_mkdir(directory, p, 0755, 0, 0);

src/shared/condition.c

@@ -922,7 +922,7 @@ static int condition_test_directory_not_empty(Condition *c, char **env) {
         assert(c->parameter);
         assert(c->type == CONDITION_DIRECTORY_NOT_EMPTY);
 
-        r = dir_is_empty(c->parameter);
+        r = dir_is_empty(c->parameter, /* ignore_hidden_or_backup= */ true);
         return r <= 0 && !IN_SET(r, -ENOENT, -ENOTDIR);
 }
 

src/shared/copy.c

@@ -905,7 +905,7 @@ static int fd_copy_directory(
 
         exists = false;
         if (copy_flags & COPY_MERGE_EMPTY) {
-                r = dir_is_empty_at(dt, to);
+                r = dir_is_empty_at(dt, to, /* ignore_hidden_or_backup= */ false);
                 if (r < 0 && r != -ENOENT)
                         return r;
                 else if (r == 1)

src/shared/dissect-image.c

@@ -1552,7 +1552,7 @@ int dissected_image_mount(
                                 if (r < 0) {
                                         if (r != -ENOENT)
                                                 return r;
-                                } else if (dir_is_empty(p) > 0) {
+                                } else if (dir_is_empty(p, /* ignore_hidden_or_backup= */ false) > 0) {
                                         /* It exists and is an empty directory. Let's mount the ESP there. */
                                         r = mount_partition(m->partitions + PARTITION_ESP, where, "/boot", uid_shift, uid_range, flags);
                                         if (r < 0)

src/shared/tpm2-util.c

@@ -1466,7 +1466,7 @@ Tpm2Support tpm2_support(void) {
                  * got the host sysfs mounted. Since devices are generally not virtualized for containers,
                  * let's assume containers never have a TPM, at least for now. */
 
-                r = dir_is_empty("/sys/class/tpmrm");
+                r = dir_is_empty("/sys/class/tpmrm", /* ignore_hidden_or_backup= */ false);
                 if (r < 0) {
                         if (r != -ENOENT)
                                 log_debug_errno(r, "Unable to test whether /sys/class/tpmrm/ exists and is populated, assuming it is not: %m");

src/sysext/sysext.c

@@ -296,7 +296,7 @@ static int merge_hierarchy(
         else if (r < 0)
                 return log_error_errno(r, "Failed to resolve host hierarchy '%s': %m", hierarchy);
         else {
-                r = dir_is_empty(resolved_hierarchy);
+                r = dir_is_empty(resolved_hierarchy, /* ignore_hidden_or_backup= */ false);
                 if (r < 0)
                         return log_error_errno(r, "Failed to check if host hierarchy '%s' is empty: %m", resolved_hierarchy);
                 if (r > 0) {
@@ -337,7 +337,7 @@ static int merge_hierarchy(
                 if (r < 0)
                         return log_error_errno(r, "Failed to resolve hierarchy '%s' in extension '%s': %m", hierarchy, *p);
 
-                r = dir_is_empty(resolved);
+                r = dir_is_empty(resolved, /* ignore_hidden_or_backup= */ false);
                 if (r < 0)
                         return log_error_errno(r, "Failed to check if hierarchy '%s' in extension '%s' is empty: %m", resolved, *p);
                 if (r > 0) {

src/test/test-stat-util.c

@@ -153,17 +153,17 @@ TEST(dir_is_empty) {
         _cleanup_(rm_rf_physical_and_freep) char *empty_dir = NULL;
         _cleanup_free_ char *j = NULL, *jj = NULL, *jjj = NULL;
 
-        assert_se(dir_is_empty_at(AT_FDCWD, "/proc") == 0);
-        assert_se(dir_is_empty_at(AT_FDCWD, "/icertainlydontexistdoi") == -ENOENT);
+        assert_se(dir_is_empty_at(AT_FDCWD, "/proc", /* ignore_hidden_or_backup= */ true) == 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, "/icertainlydontexistdoi", /* ignore_hidden_or_backup= */ true) == -ENOENT);
 
         assert_se(mkdtemp_malloc("/tmp/emptyXXXXXX", &empty_dir) >= 0);
-        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir) > 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir, /* ignore_hidden_or_backup= */ true) > 0);
 
         j = path_join(empty_dir, "zzz");
         assert_se(j);
         assert_se(touch(j) >= 0);
 
-        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir) == 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir, /* ignore_hidden_or_backup= */ true) == 0);
 
         jj = path_join(empty_dir, "ppp");
         assert_se(jj);
@@ -173,13 +173,17 @@ TEST(dir_is_empty) {
         assert_se(jjj);
         assert_se(touch(jjj) >= 0);
 
-        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir) == 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir, /* ignore_hidden_or_backup= */ true) == 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir, /* ignore_hidden_or_backup= */ false) == 0);
         assert_se(unlink(j) >= 0);
-        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir) == 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir, /* ignore_hidden_or_backup= */ true) == 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir, /* ignore_hidden_or_backup= */ false) == 0);
         assert_se(unlink(jj) >= 0);
-        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir) > 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir, /* ignore_hidden_or_backup= */ true) > 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir, /* ignore_hidden_or_backup= */ false) == 0);
         assert_se(unlink(jjj) >= 0);
-        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir) > 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir, /* ignore_hidden_or_backup= */ true) > 0);
+        assert_se(dir_is_empty_at(AT_FDCWD, empty_dir, /* ignore_hidden_or_backup= */ false) > 0);
 }
 
 static int intro(void) {