dissect-image: port mount_image_privately_interactively() to use /run/systemd/mount-rootfs/ too

Let's use the same common directory as the unit logic uses.

This means we have less to clean up, and opens the door to eventually
allow unprivileged operation of the
mount_image_privately_interactively() logic.

12 files changed, 43 insertions, 39 deletions

diff --git a/src/analyze/analyze.c b/src/analyze/analyze.c
index 09a38e7930..b555c713fc 100644
--- a/src/analyze/analyze.c
+++ b/src/analyze/analyze.c
@@ -599,7 +599,7 @@ static int parse_argv(int argc, char *argv[]) {
 
 static int run(int argc, char *argv[]) {
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *unlink_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
 
         static const Verb verbs[] = {
                 { "help",              VERB_ANY, VERB_ANY, 0,            help                   },
@@ -660,13 +660,13 @@ static int run(int argc, char *argv[]) {
                                 DISSECT_IMAGE_GENERIC_ROOT |
                                 DISSECT_IMAGE_RELAX_VAR_CHECK |
                                 DISSECT_IMAGE_READ_ONLY,
-                                &unlink_dir,
+                                &mounted_dir,
                                 /* ret_dir_fd= */ NULL,
                                 &loop_device);
                 if (r < 0)
                         return r;
 
-                arg_root = strdup(unlink_dir);
+                arg_root = strdup(mounted_dir);
                 if (!arg_root)
                         return log_oom();
         }
diff --git a/src/boot/bootctl.c b/src/boot/bootctl.c
index 0480e320c0..65608f5e83 100644
--- a/src/boot/bootctl.c
+++ b/src/boot/bootctl.c
@@ -445,7 +445,7 @@ static int bootctl_main(int argc, char *argv[]) {
 
 static int run(int argc, char *argv[]) {
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *unlink_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
         int r;
 
         log_setup();
@@ -493,13 +493,13 @@ static int run(int argc, char *argv[]) {
                                 arg_image_policy,
                                 DISSECT_IMAGE_GENERIC_ROOT |
                                 DISSECT_IMAGE_RELAX_VAR_CHECK,
-                                &unlink_dir,
+                                &mounted_dir,
                                 /* ret_dir_fd= */ NULL,
                                 &loop_device);
                 if (r < 0)
                         return r;
 
-                arg_root = strdup(unlink_dir);
+                arg_root = strdup(mounted_dir);
                 if (!arg_root)
                         return log_oom();
         }
diff --git a/src/coredump/coredumpctl.c b/src/coredump/coredumpctl.c
index bc52cc0b06..e34d74765e 100644
--- a/src/coredump/coredumpctl.c
+++ b/src/coredump/coredumpctl.c
@@ -1350,7 +1350,7 @@ static int coredumpctl_main(int argc, char *argv[]) {
 
 static int run(int argc, char *argv[]) {
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *mounted_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
         int r, units_active;
 
         setlocale(LC_ALL, "");
diff --git a/src/firstboot/firstboot.c b/src/firstboot/firstboot.c
index 71b1e25c9d..6d50054baf 100644
--- a/src/firstboot/firstboot.c
+++ b/src/firstboot/firstboot.c
@@ -1506,7 +1506,7 @@ static int parse_argv(int argc, char *argv[]) {
 
 static int run(int argc, char *argv[]) {
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *unlink_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
         _cleanup_close_ int rfd = -EBADF;
         int r;
 
@@ -1546,13 +1546,13 @@ static int run(int argc, char *argv[]) {
                                 DISSECT_IMAGE_RELAX_VAR_CHECK |
                                 DISSECT_IMAGE_FSCK |
                                 DISSECT_IMAGE_GROWFS,
-                                &unlink_dir,
+                                &mounted_dir,
                                 &rfd,
                                 &loop_device);
                 if (r < 0)
                         return r;
 
-                arg_root = strdup(unlink_dir);
+                arg_root = strdup(mounted_dir);
                 if (!arg_root)
                         return log_oom();
         } else {
diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c
index 12119b302c..62f74551ad 100644
--- a/src/journal/journalctl.c
+++ b/src/journal/journalctl.c
@@ -2112,7 +2112,7 @@ static int wait_for_change(sd_journal *j, int poll_fd) {
 
 static int run(int argc, char *argv[]) {
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *unlink_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
         bool previous_boot_id_valid = false, first_line = true, ellipsized = false, need_seek = false, since_seeked = false;
         bool use_cursor = false, after_cursor = false;
         _cleanup_(sd_journal_closep) sd_journal *j = NULL;
@@ -2143,13 +2143,13 @@ static int run(int argc, char *argv[]) {
                                 DISSECT_IMAGE_VALIDATE_OS |
                                 DISSECT_IMAGE_RELAX_VAR_CHECK |
                                 (arg_action == ACTION_UPDATE_CATALOG ? DISSECT_IMAGE_FSCK|DISSECT_IMAGE_GROWFS : DISSECT_IMAGE_READ_ONLY),
-                                &unlink_dir,
+                                &mounted_dir,
                                 /* ret_dir_fd= */ NULL,
                                 &loop_device);
                 if (r < 0)
                         return r;
 
-                arg_root = strdup(unlink_dir);
+                arg_root = strdup(mounted_dir);
                 if (!arg_root)
                         return log_oom();
         }
diff --git a/src/machine-id-setup/machine-id-setup-main.c b/src/machine-id-setup/machine-id-setup-main.c
index 38d66def06..59aad985f8 100644
--- a/src/machine-id-setup/machine-id-setup-main.c
+++ b/src/machine-id-setup/machine-id-setup-main.c
@@ -136,7 +136,7 @@ static int parse_argv(int argc, char *argv[]) {
 
 static int run(int argc, char *argv[]) {
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *unlink_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
         int r;
 
         log_parse_environment();
@@ -157,13 +157,13 @@ static int run(int argc, char *argv[]) {
                                 DISSECT_IMAGE_RELAX_VAR_CHECK |
                                 DISSECT_IMAGE_FSCK |
                                 DISSECT_IMAGE_GROWFS,
-                                &unlink_dir,
+                                &mounted_dir,
                                 /* ret_dir_fd= */ NULL,
                                 &loop_device);
                 if (r < 0)
                         return r;
 
-                arg_root = strdup(unlink_dir);
+                arg_root = strdup(mounted_dir);
                 if (!arg_root)
                         return log_oom();
         }
diff --git a/src/partition/repart.c b/src/partition/repart.c
index 1f3e78a84e..995a40655d 100644
--- a/src/partition/repart.c
+++ b/src/partition/repart.c
@@ -6669,7 +6669,7 @@ static int determine_auto_size(Context *c) {
 
 static int run(int argc, char *argv[]) {
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *mounted_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
         _cleanup_(context_freep) Context* context = NULL;
         bool node_is_our_loop = false;
         int r;
diff --git a/src/shared/dissect-image.c b/src/shared/dissect-image.c
index b84ef46442..39f75dd0dd 100644
--- a/src/shared/dissect-image.c
+++ b/src/shared/dissect-image.c
@@ -3667,8 +3667,7 @@ int mount_image_privately_interactively(
         _cleanup_(verity_settings_done) VeritySettings verity = VERITY_SETTINGS_DEFAULT;
         _cleanup_(loop_device_unrefp) LoopDevice *d = NULL;
         _cleanup_(dissected_image_unrefp) DissectedImage *dissected_image = NULL;
-        _cleanup_(rmdir_and_freep) char *created_dir = NULL;
-        _cleanup_free_ char *temp = NULL;
+        _cleanup_free_ char *dir = NULL;
         int r;
 
         /* Mounts an OS image at a temporary place, inside a newly created mount namespace of our own. This
@@ -3676,7 +3675,6 @@ int mount_image_privately_interactively(
          * easily. */
 
         assert(image);
-        assert(ret_directory);
         assert(ret_loop_device);
 
         /* We intend to mount this right-away, hence add the partitions if needed and pin them. */
@@ -3687,10 +3685,6 @@ int mount_image_privately_interactively(
         if (r < 0)
                 return log_error_errno(r, "Failed to load root hash data: %m");
 
-        r = tempfn_random_child(NULL, program_invocation_short_name, &temp);
-        if (r < 0)
-                return log_error_errno(r, "Failed to generate temporary mount directory: %m");
-
         r = loop_device_make_by_path(
                         image,
                         FLAGS_SET(flags, DISSECT_IMAGE_DEVICE_READ_ONLY) ? O_RDONLY : O_RDWR,
@@ -3723,13 +3717,16 @@ int mount_image_privately_interactively(
         if (r < 0)
                 return log_error_errno(r, "Failed to detach mount namespace: %m");
 
-        r = mkdir_p(temp, 0700);
+        r = mkdir_p("/run/systemd/mount-rootfs", 0555);
         if (r < 0)
                 return log_error_errno(r, "Failed to create mount point: %m");
 
-        created_dir = TAKE_PTR(temp);
-
-        r = dissected_image_mount_and_warn(dissected_image, created_dir, UID_INVALID, UID_INVALID, flags);
+        r = dissected_image_mount_and_warn(
+                        dissected_image,
+                        "/run/systemd/mount-rootfs",
+                        /* uid_shift= */ UID_INVALID,
+                        /* uid_range= */ UID_INVALID,
+                        flags);
         if (r < 0)
                 return r;
 
@@ -3741,19 +3738,26 @@ int mount_image_privately_interactively(
         if (r < 0)
                 return log_error_errno(r, "Failed to relinquish DM and loopback block devices: %m");
 
+        if (ret_directory) {
+                dir = strdup("/run/systemd/mount-rootfs");
+                if (!dir)
+                        return log_oom();
+        }
+
         if (ret_dir_fd) {
                 _cleanup_close_ int dir_fd = -EBADF;
 
-                dir_fd = open(created_dir, O_CLOEXEC|O_DIRECTORY);
+                dir_fd = open("/run/systemd/mount-rootfs", O_CLOEXEC|O_DIRECTORY);
                 if (dir_fd < 0)
                         return log_error_errno(errno, "Failed to open mount point directory: %m");
 
                 *ret_dir_fd = TAKE_FD(dir_fd);
         }
 
-        *ret_directory = TAKE_PTR(created_dir);
-        *ret_loop_device = TAKE_PTR(d);
+        if (ret_directory)
+                *ret_directory = TAKE_PTR(dir);
 
+        *ret_loop_device = TAKE_PTR(d);
         return 0;
 }
 
diff --git a/src/systemctl/systemctl.c b/src/systemctl/systemctl.c
index 71c068b09e..b31a59785b 100644
--- a/src/systemctl/systemctl.c
+++ b/src/systemctl/systemctl.c
@@ -1224,7 +1224,7 @@ static int systemctl_main(int argc, char *argv[]) {
 
 static int run(int argc, char *argv[]) {
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *mounted_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
         int r;
 
         setlocale(LC_ALL, "");
diff --git a/src/sysupdate/sysupdate.c b/src/sysupdate/sysupdate.c
index 29cd552ea8..76777dc08e 100644
--- a/src/sysupdate/sysupdate.c
+++ b/src/sysupdate/sysupdate.c
@@ -861,7 +861,7 @@ static int process_image(
                 LoopDevice **ret_loop_device) {
 
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *mounted_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
         int r;
 
         assert(ret_mounted_dir);
diff --git a/src/sysusers/sysusers.c b/src/sysusers/sysusers.c
index 58246b5d85..aa1f1356dc 100644
--- a/src/sysusers/sysusers.c
+++ b/src/sysusers/sysusers.c
@@ -2157,7 +2157,7 @@ static int read_credential_lines(void) {
 static int run(int argc, char *argv[]) {
 #ifndef STANDALONE
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *unlink_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
 #endif
         _cleanup_close_ int lock = -EBADF;
         Item *i;
@@ -2191,13 +2191,13 @@ static int run(int argc, char *argv[]) {
                                 DISSECT_IMAGE_RELAX_VAR_CHECK |
                                 DISSECT_IMAGE_FSCK |
                                 DISSECT_IMAGE_GROWFS,
-                                &unlink_dir,
+                                &mounted_dir,
                                 /* ret_dir_fd= */ NULL,
                                 &loop_device);
                 if (r < 0)
                         return r;
 
-                arg_root = strdup(unlink_dir);
+                arg_root = strdup(mounted_dir);
                 if (!arg_root)
                         return log_oom();
         }
diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c
index 382fa8b56a..be04b25653 100644
--- a/src/tmpfiles/tmpfiles.c
+++ b/src/tmpfiles/tmpfiles.c
@@ -4223,7 +4223,7 @@ DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(item_array_hash_ops, char, string_
 static int run(int argc, char *argv[]) {
 #ifndef STANDALONE
         _cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
-        _cleanup_(umount_and_rmdir_and_freep) char *unlink_dir = NULL;
+        _cleanup_(umount_and_freep) char *mounted_dir = NULL;
 #endif
         _cleanup_strv_free_ char **config_dirs = NULL;
         bool invalid_config = false;
@@ -4314,13 +4314,13 @@ static int run(int argc, char *argv[]) {
                                 DISSECT_IMAGE_RELAX_VAR_CHECK |
                                 DISSECT_IMAGE_FSCK |
                                 DISSECT_IMAGE_GROWFS,
-                                &unlink_dir,
+                                &mounted_dir,
                                 /* ret_dir_fd= */ NULL,
                                 &loop_device);
                 if (r < 0)
                         return r;
 
-                arg_root = strdup(unlink_dir);
+                arg_root = strdup(mounted_dir);
                 if (!arg_root)
                         return log_oom();
         }