CODING_STYLE: add a brief log msg style guide

Added sensor configuration for Toshiba Encore WT10A-108 tablet.

docs/CODING_STYLE.md

@@ -699,6 +699,26 @@ SPDX-License-Identifier: LGPL-2.1-or-later
           return log_error_errno(SYNTHETIC_ERRNO(EIO), "Failed to read ...");
   ```
 
+- When generating log messages that contain filenames, user controlled strings,
+  or similar, please enclose them in single ticks.
+
+- Think about the log level you choose: for functions that are of the "logging"
+  kind (see above), please ensure that failures we propagate should be logged
+  about at `LOG_ERR` level. Failures that are noteworthy, but we proceed anyway,
+  should be loged at `LOG_WARN` level. Important informational messages should
+  use `LOG_NOTICE` and regular informational messages should use
+  `LOG_INFO`. Note that the latter is the default maximum log level, i.e. only
+  `LOG_DEBUG` messages are hidden by default.
+
+- All log messages that show some failure which is not fatal for the immediate
+  operation (i.e. generally those you'd log at `LOG_WARN` level, as described
+  above) should be suffixed with a `…, ignoring: %m"` or similar. Or in other
+  words, they should make clear not only in log level but also in English
+  language that the issue is not fatal, but ignored. Depending on context you
+  can also use `…, proceeding anyway: %m"`, `…, skipping: %m` or other language
+  that makes clear that the failure is not actionable and doesn't strictly
+  require immediate administrator attention.
+
 ## Memory Allocation
 
 - Always check OOM. There is no excuse. In program code, you can use

hwdb.d/60-sensor.hwdb

@@ -1194,6 +1194,10 @@ sensor:modalias:acpi:INVN6500*:dmi:*:svnTOSHIBA:pnTOSHIBAWT10-A-103:*
 sensor:modalias:acpi:INVN6500*:dmi:*:svnTOSHIBA:pnTOSHIBAWT10-A-102:*
  ACCEL_MOUNT_MATRIX=0, -1, 0; -1, 0, 0; 0, 0, 1
 
+# Toshiba Encore WT10A-108 tablet
+sensor:modalias:acpi:INVN6500*:dmi:*:svnTOSHIBA:pnTOSHIBAWT10-A-108:*
+ ACCEL_MOUNT_MATRIX=0, -1, 0; -1, 0, 0; 0, 0, 1
+
 #########################################
 # Trekstor
 #########################################

man/systemd-dissect.xml

@@ -551,6 +551,19 @@
         <xi:include href="version-info.xml" xpointer="v254"/></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><option>--copy-ownership=</option></term>
+
+        <listitem><para>Controls whether file ownership (user and group) is preserved when copying files
+        with <option>--copy-from</option> or <option>--copy-to</option>. Takes a boolean. If
+        <literal>yes</literal>, ownership is always preserved. If <literal>no</literal>, ownership is never
+        preserved and the current user's UID/GID is used instead. If not specified, ownership is preserved
+        when copying directory trees, but not when copying individual regular files.
+        </para>
+
+        <xi:include href="version-info.xml" xpointer="v260"/></listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><option>--system</option></term>
         <term><option>--user</option></term>

src/dissect/dissect.c

@@ -14,6 +14,7 @@
 #include "argv-util.h"
 #include "blockdev-util.h"
 #include "build.h"
+#include "capability-util.h"
 #include "chase.h"
 #include "copy.h"
 #include "device-util.h"
@@ -108,6 +109,7 @@ static bool arg_all = false;
 static uid_t arg_uid_base = UID_INVALID;
 static bool arg_quiet = false;
 static ImageFilter *arg_image_filter = NULL;
+static int arg_copy_ownership = -1;
 
 STATIC_DESTRUCTOR_REGISTER(arg_image, freep);
 STATIC_DESTRUCTOR_REGISTER(arg_root, freep);
@@ -169,6 +171,8 @@ static int help(void) {
                "     --loop-ref=NAME      Set reference string for loopback device\n"
                "     --loop-ref-auto      Derive reference string from image file name\n"
                "     --mtree-hash=BOOL    Whether to include SHA256 hash in the mtree output\n"
+               "     --copy-ownership=BOOL\n"
+               "                          Whether to copy ownership when copying files\n"
                "     --user               Discover user images\n"
                "     --system             Discover system images\n"
                "     --all                Show hidden images too\n"
@@ -305,48 +309,50 @@ static int parse_argv(int argc, char *argv[]) {
                 ARG_USER,
                 ARG_ALL,
                 ARG_IMAGE_FILTER,
+                ARG_COPY_OWNERSHIP,
         };
 
         static const struct option options[] = {
-                { "help",          no_argument,       NULL, 'h'               },
-                { "version",       no_argument,       NULL, ARG_VERSION       },
-                { "no-pager",      no_argument,       NULL, ARG_NO_PAGER      },
-                { "no-legend",     no_argument,       NULL, ARG_NO_LEGEND     },
-                { "mount",         no_argument,       NULL, 'm'               },
-                { "umount",        no_argument,       NULL, 'u'               },
-                { "attach",        no_argument,       NULL, ARG_ATTACH        },
-                { "detach",        no_argument,       NULL, ARG_DETACH        },
-                { "with",          no_argument,       NULL, ARG_WITH          },
-                { "read-only",     no_argument,       NULL, 'r'               },
-                { "discard",       required_argument, NULL, ARG_DISCARD       },
-                { "fsck",          required_argument, NULL, ARG_FSCK          },
-                { "growfs",        required_argument, NULL, ARG_GROWFS        },
-                { "root-hash",     required_argument, NULL, ARG_ROOT_HASH     },
-                { "root-hash-sig", required_argument, NULL, ARG_ROOT_HASH_SIG },
-                { "usr-hash",      required_argument, NULL, ARG_USR_HASH      },
-                { "usr-hash-sig",  required_argument, NULL, ARG_USR_HASH_SIG  },
-                { "verity-data",   required_argument, NULL, ARG_VERITY_DATA   },
-                { "mkdir",         no_argument,       NULL, ARG_MKDIR         },
-                { "rmdir",         no_argument,       NULL, ARG_RMDIR         },
-                { "in-memory",     no_argument,       NULL, ARG_IN_MEMORY     },
-                { "list",          no_argument,       NULL, 'l'               },
-                { "mtree",         no_argument,       NULL, ARG_MTREE         },
-                { "copy-from",     no_argument,       NULL, 'x'               },
-                { "copy-to",       no_argument,       NULL, 'a'               },
-                { "json",          required_argument, NULL, ARG_JSON          },
-                { "discover",      no_argument,       NULL, ARG_DISCOVER      },
-                { "loop-ref",      required_argument, NULL, ARG_LOOP_REF      },
-                { "loop-ref-auto", no_argument,       NULL, ARG_LOOP_REF_AUTO },
-                { "image-policy",  required_argument, NULL, ARG_IMAGE_POLICY  },
-                { "validate",      no_argument,       NULL, ARG_VALIDATE      },
-                { "mtree-hash",    required_argument, NULL, ARG_MTREE_HASH    },
-                { "make-archive",  no_argument,       NULL, ARG_MAKE_ARCHIVE  },
-                { "shift",         no_argument,       NULL, ARG_SHIFT         },
-                { "system",        no_argument,       NULL, ARG_SYSTEM        },
-                { "user",          no_argument,       NULL, ARG_USER          },
-                { "all",           no_argument,       NULL, ARG_ALL           },
-                { "quiet",         no_argument,       NULL, 'q'               },
-                { "image-filter",  required_argument, NULL, ARG_IMAGE_FILTER  },
+                { "help",           no_argument,       NULL, 'h'                },
+                { "version",        no_argument,       NULL, ARG_VERSION        },
+                { "no-pager",       no_argument,       NULL, ARG_NO_PAGER       },
+                { "no-legend",      no_argument,       NULL, ARG_NO_LEGEND      },
+                { "mount",          no_argument,       NULL, 'm'                },
+                { "umount",         no_argument,       NULL, 'u'                },
+                { "attach",         no_argument,       NULL, ARG_ATTACH         },
+                { "detach",         no_argument,       NULL, ARG_DETACH         },
+                { "with",           no_argument,       NULL, ARG_WITH           },
+                { "read-only",      no_argument,       NULL, 'r'                },
+                { "discard",        required_argument, NULL, ARG_DISCARD        },
+                { "fsck",           required_argument, NULL, ARG_FSCK           },
+                { "growfs",         required_argument, NULL, ARG_GROWFS         },
+                { "root-hash",      required_argument, NULL, ARG_ROOT_HASH      },
+                { "root-hash-sig",  required_argument, NULL, ARG_ROOT_HASH_SIG  },
+                { "usr-hash",       required_argument, NULL, ARG_USR_HASH       },
+                { "usr-hash-sig",   required_argument, NULL, ARG_USR_HASH_SIG   },
+                { "verity-data",    required_argument, NULL, ARG_VERITY_DATA    },
+                { "mkdir",          no_argument,       NULL, ARG_MKDIR          },
+                { "rmdir",          no_argument,       NULL, ARG_RMDIR          },
+                { "in-memory",      no_argument,       NULL, ARG_IN_MEMORY      },
+                { "list",           no_argument,       NULL, 'l'                },
+                { "mtree",          no_argument,       NULL, ARG_MTREE          },
+                { "copy-from",      no_argument,       NULL, 'x'                },
+                { "copy-to",        no_argument,       NULL, 'a'                },
+                { "json",           required_argument, NULL, ARG_JSON           },
+                { "discover",       no_argument,       NULL, ARG_DISCOVER       },
+                { "loop-ref",       required_argument, NULL, ARG_LOOP_REF       },
+                { "loop-ref-auto",  no_argument,       NULL, ARG_LOOP_REF_AUTO  },
+                { "image-policy",   required_argument, NULL, ARG_IMAGE_POLICY   },
+                { "validate",       no_argument,       NULL, ARG_VALIDATE       },
+                { "mtree-hash",     required_argument, NULL, ARG_MTREE_HASH     },
+                { "make-archive",   no_argument,       NULL, ARG_MAKE_ARCHIVE   },
+                { "shift",          no_argument,       NULL, ARG_SHIFT          },
+                { "system",         no_argument,       NULL, ARG_SYSTEM         },
+                { "user",           no_argument,       NULL, ARG_USER           },
+                { "all",            no_argument,       NULL, ARG_ALL            },
+                { "quiet",          no_argument,       NULL, 'q'                },
+                { "image-filter",   required_argument, NULL, ARG_IMAGE_FILTER   },
+                { "copy-ownership", required_argument, NULL, ARG_COPY_OWNERSHIP },
                 {}
         };
 
@@ -630,6 +636,12 @@ static int parse_argv(int argc, char *argv[]) {
                         break;
                 }
 
+                case ARG_COPY_OWNERSHIP:
+                        r = parse_tristate_argument("--copy-ownership=", optarg, &arg_copy_ownership);
+                        if (r < 0)
+                                return r;
+                        break;
+
                 case '?':
                         return -EINVAL;
 
@@ -837,8 +849,25 @@ static int parse_argv(int argc, char *argv[]) {
         } else
                 arg_via_service = r;
 
-        if (!IN_SET(arg_action, ACTION_DISSECT, ACTION_LIST, ACTION_MTREE, ACTION_COPY_FROM, ACTION_COPY_TO, ACTION_DISCOVER, ACTION_VALIDATE) && geteuid() != 0)
-                return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be root.");
+        r = have_effective_cap(CAP_SYS_ADMIN);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine if we have CAP_SYS_ADMIN: %m");
+
+        if (IN_SET(arg_action, ACTION_MOUNT, ACTION_UMOUNT) && r == 0)
+                return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to have CAP_SYS_ADMIN to mount/unmount images");
+
+        r = have_effective_cap(CAP_CHOWN);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine if we have CAP_CHOWN: %m");
+
+        if (arg_action == ACTION_SHIFT && r == 0)
+                return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to have CAP_CHOWN to shift UID ranges");
+
+        if (IN_SET(arg_action, ACTION_ATTACH, ACTION_DETACH)) {
+                r = must_be_root();
+                if (r < 0)
+                        return r;
+        }
 
         SET_FLAG(arg_flags, DISSECT_IMAGE_ALLOW_INTERACTIVE_AUTH, isatty_safe(STDIN_FILENO));
 
@@ -1439,6 +1468,13 @@ static int action_list_or_mtree_or_copy_or_make_archive(DissectedImage *m, LoopD
 
         assert(IN_SET(arg_action, ACTION_LIST, ACTION_MTREE, ACTION_COPY_FROM, ACTION_COPY_TO, ACTION_MAKE_ARCHIVE, ACTION_SHIFT));
 
+        /* Determine whether to copy ownership:
+         * --copy-ownership=yes: always try to preserve ownership
+         * --copy-ownership=no: never preserve ownership, use current user
+         * --copy-ownership=auto (default): preserve ownership for directory trees,
+         *                              but not for regular files (since DDI password tables are typically
+         *                              distinct from the host ones, individual file ownership is less meaningful) */
+
         if (arg_image) {
                 assert(m);
 
@@ -1501,7 +1537,12 @@ static int action_list_or_mtree_or_copy_or_make_archive(DissectedImage *m, LoopD
                 }
 
                 /* Try to copy as directory? */
-                r = copy_directory_at(source_fd, NULL, AT_FDCWD, arg_target, COPY_REFLINK|COPY_MERGE|COPY_REPLACE|COPY_SIGINT|COPY_HARDLINKS);
+                r = copy_directory_at(
+                                source_fd, /* from= */ NULL,
+                                AT_FDCWD, arg_target,
+                                arg_copy_ownership == 0 ? getuid() : UID_INVALID,
+                                arg_copy_ownership == 0 ? getgid() : GID_INVALID,
+                                COPY_REFLINK|COPY_MERGE|COPY_REPLACE|COPY_SIGINT|COPY_HARDLINKS);
                 if (r >= 0)
                         return 0;
                 if (r != -ENOTDIR)
@@ -1524,9 +1565,10 @@ static int action_list_or_mtree_or_copy_or_make_archive(DissectedImage *m, LoopD
 
                 (void) copy_xattr(source_fd, NULL, target_fd, NULL, 0);
                 (void) copy_access(source_fd, target_fd);
+                if (arg_copy_ownership > 0)
+                        (void) copy_owner(source_fd, target_fd);
                 (void) copy_times(source_fd, target_fd, 0);
 
-                /* When this is a regular file we don't copy ownership! */
                 return 0;
         }
 
@@ -1580,9 +1622,23 @@ static int action_list_or_mtree_or_copy_or_make_archive(DissectedImage *m, LoopD
                                 if (errno != ENOENT)
                                         return log_error_errno(errno, "Failed to open destination '%s': %m", arg_target);
 
-                                r = copy_tree_at(source_fd, ".", dfd, bn, UID_INVALID, GID_INVALID, COPY_REFLINK|COPY_MERGE|COPY_REPLACE|COPY_SIGINT|COPY_HARDLINKS, NULL, NULL);
+                                r = copy_tree_at(
+                                                source_fd, ".",
+                                                dfd, bn,
+                                                arg_copy_ownership == 0 ? getuid() : UID_INVALID,
+                                                arg_copy_ownership == 0 ? getgid() : GID_INVALID,
+                                                COPY_REFLINK|COPY_MERGE|COPY_REPLACE|COPY_SIGINT|COPY_HARDLINKS,
+                                                /* denylist= */ NULL,
+                                                /* subvolumes= */ NULL);
                         } else
-                                r = copy_tree_at(source_fd, ".", target_fd, ".", UID_INVALID, GID_INVALID, COPY_REFLINK|COPY_MERGE|COPY_REPLACE|COPY_SIGINT|COPY_HARDLINKS, NULL, NULL);
+                                r = copy_tree_at(
+                                                source_fd, ".",
+                                                target_fd, ".",
+                                                arg_copy_ownership == 0 ? getuid() : UID_INVALID,
+                                                arg_copy_ownership == 0 ? getgid() : GID_INVALID,
+                                                COPY_REFLINK|COPY_MERGE|COPY_REPLACE|COPY_SIGINT|COPY_HARDLINKS,
+                                                /* denylist= */ NULL,
+                                                /* subvolumes= */ NULL);
                         if (r < 0)
                                 return log_error_errno(r, "Failed to copy '%s' to '%s' in image '%s': %m", arg_source, arg_target, arg_image);
 
@@ -1603,9 +1659,10 @@ static int action_list_or_mtree_or_copy_or_make_archive(DissectedImage *m, LoopD
 
                 (void) copy_xattr(source_fd, NULL, target_fd, NULL, 0);
                 (void) copy_access(source_fd, target_fd);
+                if (arg_copy_ownership > 0)
+                        (void) copy_owner(source_fd, target_fd);
                 (void) copy_times(source_fd, target_fd, 0);
 
-                /* When this is a regular file we don't copy ownership! */
                 return 0;
         }
 
@@ -1721,7 +1778,7 @@ static int action_umount(const char *path) {
                 return log_error_errno(r, "Failed to find backing block device for '%s': %m", canonical);
 
         r = loop_device_open(dev, 0, LOCK_EX, &d);
-        if (r < 0)
+        if (r < 0 && !ERRNO_IS_PRIVILEGE(r))
                 return log_device_error_errno(dev, r, "Failed to open loopback block device: %m");
 
         /* We've locked the loop device, now we're ready to unmount. To allow the unmount to succeed, we have
@@ -1733,7 +1790,8 @@ static int action_umount(const char *path) {
                 return log_error_errno(r, "Failed to unmount '%s': %m", canonical);
 
         /* We managed to lock and unmount successfully? That means we can try to remove the loop device. */
-        loop_device_unrelinquish(d);
+        if (d)
+                loop_device_unrelinquish(d);
 
         if (arg_rmdir) {
                 r = RET_NERRNO(rmdir(canonical));
@@ -1785,7 +1843,7 @@ static int action_with(DissectedImage *m, LoopDevice *d) {
                         return log_error_errno(r, "Failed to unlock loopback block device: %m");
         }
 
-        rcode = pidref_safe_fork("(with)", FORK_CLOSE_ALL_FDS|FORK_LOG|FORK_WAIT, /* ret= */ NULL);
+        rcode = pidref_safe_fork("(with)", FORK_CLOSE_ALL_FDS|FORK_LOG|FORK_REOPEN_LOG|FORK_WAIT, /* ret= */ NULL);
         if (rcode == 0) {
                 /* Child */
 
@@ -1799,7 +1857,7 @@ static int action_with(DissectedImage *m, LoopDevice *d) {
                         _exit(EXIT_FAILURE);
                 }
 
-                if (setenv("SYSTEMD_DISSECT_DEVICE", d->node, /* overwrite= */ true) < 0) {
+                if (d && setenv("SYSTEMD_DISSECT_DEVICE", d->node, /* overwrite= */ true) < 0) {
                         log_error_errno(errno, "Failed to set $SYSTEMD_DISSECT_DEVICE: %m");
                         _exit(EXIT_FAILURE);
                 }
@@ -1839,7 +1897,7 @@ static int action_with(DissectedImage *m, LoopDevice *d) {
         created_dir = TAKE_PTR(mounted_dir);
 
         if (rmdir(created_dir) < 0)
-                log_warning_errno(r, "Failed to remove directory '%s', ignoring: %m", created_dir);
+                log_warning_errno(errno, "Failed to remove directory '%s', ignoring: %m", created_dir);
 
         temp = TAKE_PTR(created_dir);
 
@@ -2114,7 +2172,7 @@ static int run(int argc, char *argv[]) {
                         else
                                 r = loop_device_make_by_path(arg_image, open_flags, /* sector_size= */ UINT32_MAX, loop_flags, LOCK_SH, &d);
                         if (r < 0) {
-                                if (!ERRNO_IS_PRIVILEGE(r) || !IN_SET(arg_action, ACTION_DISSECT, ACTION_LIST, ACTION_MTREE, ACTION_COPY_FROM, ACTION_COPY_TO, ACTION_SHIFT))
+                                if (!ERRNO_IS_PRIVILEGE(r) || !IN_SET(arg_action, ACTION_MOUNT, ACTION_UMOUNT, ACTION_WITH, ACTION_DISSECT, ACTION_LIST, ACTION_MTREE, ACTION_COPY_FROM, ACTION_COPY_TO, ACTION_SHIFT))
                                         return log_error_errno(r, "Failed to set up loopback device for %s: %m", arg_image);
 
                                 log_debug_errno(r, "Lacking permissions to set up loopback block device for %s, using service: %m", arg_image);
@@ -2180,8 +2238,9 @@ static int run(int argc, char *argv[]) {
                         if (arg_loop_ref || arg_loop_ref_auto) /* yes, the 2nd check is strictly speaking redundant, given the normalization we did above, but let's be explicit here */
                                 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "--loop-ref=/--loop-ref-auto not supported when operating via systemd-mountfsd.");
 
-                        /* Don't run things in private userns, if the mount shall be attached to the host */
-                        if (!IN_SET(arg_action, ACTION_MOUNT, ACTION_WITH)) {
+                        /* Don't run things in private userns, if the mount shall be attached to the host
+                         * or if we're copying from/to the host. */
+                        if (!IN_SET(arg_action, ACTION_MOUNT, ACTION_WITH, ACTION_COPY_FROM, ACTION_COPY_TO)) {
                                 userns_fd = nsresource_allocate_userns(/* name= */ NULL, NSRESOURCE_UIDS_64K); /* allocate 64K users by default */
                                 if (userns_fd < 0)
                                         return log_error_errno(userns_fd, "Failed to allocate user namespace with 64K users: %m");

src/import/import-fs.c

@@ -223,6 +223,8 @@ static int import_fs(int argc, char *argv[], void *userdata) {
                         r = copy_directory_at_full(
                                         fd, NULL,
                                         AT_FDCWD, dest,
+                                        /* override_uid= */ UID_INVALID,
+                                        /* override_gid= */ GID_INVALID,
                                         COPY_REFLINK|
                                         COPY_SAME_MOUNT|
                                         COPY_HARDLINKS|

src/shared/btrfs-util.c

@@ -1480,6 +1480,8 @@ int btrfs_subvol_snapshot_at_full(
                 r = copy_directory_at_full(
                                 dir_fdf, from,
                                 new_fd, subvolume,
+                                /* override_uid= */ UID_INVALID,
+                                /* override_gid= */ GID_INVALID,
                                 COPY_MERGE_EMPTY|
                                 COPY_REFLINK|
                                 COPY_SAME_MOUNT|

src/shared/copy.c

@@ -1442,6 +1442,8 @@ int copy_directory_at_full(
                 const char *from,
                 int dir_fdt,
                 const char *to,
+                uid_t override_uid,
+                gid_t override_gid,
                 CopyFlags copy_flags,
                 copy_progress_path_t progress_path,
                 copy_progress_bytes_t progress_bytes,
@@ -1468,9 +1470,13 @@ int copy_directory_at_full(
                         dir_fdt, to,
                         st.st_dev,
                         COPY_DEPTH_MAX,
-                        UID_INVALID, GID_INVALID,
+                        override_uid,
+                        override_gid,
                         copy_flags,
-                        NULL, NULL, NULL, NULL,
+                        /* denylist= */ NULL,
+                        /* subvolumes= */ NULL,
+                        /* progress_path= */ NULL,
+                        /* progress_bytes= */ NULL,
                         progress_path,
                         progress_bytes,
                         userdata);
@@ -1750,6 +1756,18 @@ int copy_access(int fdf, int fdt) {
         return RET_NERRNO(fchmod(fdt, st.st_mode & 07777));
 }
 
+int copy_owner(int fdf, int fdt) {
+        struct stat st;
+
+        assert(fdf >= 0);
+        assert(fdt >= 0);
+
+        if (fstat(fdf, &st) < 0)
+                return -errno;
+
+        return RET_NERRNO(fchown(fdt, st.st_uid, st.st_gid));
+}
+
 int copy_rights_with_fallback(int fdf, int fdt, const char *patht) {
         struct stat st;
 

src/shared/copy.h

@@ -88,9 +88,9 @@ static inline int copy_tree(const char *from, const char *to, uid_t override_uid
         return copy_tree_at_full(AT_FDCWD, from, AT_FDCWD, to, override_uid, override_gid, copy_flags, denylist, subvolumes, NULL, NULL, NULL);
 }
 
-int copy_directory_at_full(int dir_fdf, const char *from, int dir_fdt, const char *to, CopyFlags copy_flags, copy_progress_path_t progress_path, copy_progress_bytes_t progress_bytes, void *userdata);
-static inline int copy_directory_at(int dir_fdf, const char *from, int dir_fdt, const char *to, CopyFlags copy_flags) {
-        return copy_directory_at_full(dir_fdf, from, dir_fdt, to, copy_flags, NULL, NULL, NULL);
+int copy_directory_at_full(int dir_fdf, const char *from, int dir_fdt, const char *to, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags, copy_progress_path_t progress_path, copy_progress_bytes_t progress_bytes, void *userdata);
+static inline int copy_directory_at(int dir_fdf, const char *from, int dir_fdt, const char *to, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags) {
+        return copy_directory_at_full(dir_fdf, from, dir_fdt, to, override_uid, override_gid, copy_flags, NULL, NULL, NULL);
 }
 
 int copy_bytes_full(int fdf, int fdt, uint64_t max_bytes, CopyFlags copy_flags, void **ret_remains, size_t *ret_remains_size, copy_progress_bytes_t progress, void *userdata);
@@ -100,6 +100,7 @@ static inline int copy_bytes(int fdf, int fdt, uint64_t max_bytes, CopyFlags cop
 
 int copy_times(int fdf, int fdt, CopyFlags flags);
 int copy_access(int fdf, int fdt);
+int copy_owner(int fdf, int fdt);
 int copy_rights_with_fallback(int fdf, int fdt, const char *patht);
 static inline int copy_rights(int fdf, int fdt) {
         return copy_rights_with_fallback(fdf, fdt, NULL); /* no fallback */

src/shared/shift-uid.c

@@ -387,12 +387,13 @@ read_only:
 int path_patch_uid(const char *path, uid_t shift, uid_t range) {
         _cleanup_close_ int fd = -EBADF;
         struct stat st;
+        int r;
 
         assert(path);
 
         fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
         if (fd < 0)
-                return -errno;
+                return log_debug_errno(errno, "Failed to open '%s': %m", path);
 
         /* Recursively adjusts the UID/GIDs of all files of a directory tree. This is used to automatically fix up an
          * OS tree to the used user namespace UID range. Note that this automatic adjustment only works for UID ranges
@@ -401,21 +402,30 @@ int path_patch_uid(const char *path, uid_t shift, uid_t range) {
 
         /* We only support containers where the shift starts at a 2^16 boundary */
         if ((shift & 0xFFFF) != 0)
-                return -EOPNOTSUPP;
+                return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+                                       "UID shift 0x%"PRIx32" is not at a 2^16 boundary.",
+                                       (uint32_t) shift);
 
         if (shift == UID_BUSY_BASE)
-                return -EINVAL;
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "UID shift 0x%"PRIx32" conflicts with busy base.",
+                                       (uint32_t) shift);
 
         /* We only support containers with 16-bit UID ranges for the patching logic */
         if (range != 0x10000)
-                return -EOPNOTSUPP;
+                return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+                                       "UID range 0x%"PRIx32" is not supported, must be 0x10000.",
+                                       (uint32_t) range);
 
         if (fstat(fd, &st) < 0)
-                return -errno;
+                return log_debug_errno(errno, "Failed to stat '%s': %m", path);
 
         /* We only support containers where the uid/gid container ID match */
         if ((uint32_t) st.st_uid >> 16 != (uint32_t) st.st_gid >> 16)
-                return -EBADE;
+                return log_debug_errno(SYNTHETIC_ERRNO(EBADE),
+                                       "UID container ID 0x%"PRIx32" does not match GID container ID 0x%"PRIx32".",
+                                       (uint32_t) st.st_uid >> 16,
+                                       (uint32_t) st.st_gid >> 16);
 
         /* Try to detect if the range is already right. Of course, this a pretty drastic optimization, as we assume
          * that if the top-level dir has the right upper 16-bit assigned, then everything below will have too... */
@@ -430,7 +440,11 @@ int path_patch_uid(const char *path, uid_t shift, uid_t range) {
                 if (fchown(fd,
                            UID_BUSY_BASE | (st.st_uid & ~UID_BUSY_MASK),
                            (gid_t) UID_BUSY_BASE | (st.st_gid & ~(gid_t) UID_BUSY_MASK)) < 0)
-                        return -errno;
+                        log_debug_errno(errno, "Failed to mark '%s' as busy, ignoring: %m", path);
 
-        return recurse_fd(TAKE_FD(fd), &st, shift, true);
+        r = recurse_fd(TAKE_FD(fd), &st, shift, /* is_toplevel= */ true);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to recursively patch UID/GID of '%s': %m", path);
+
+        return r;
 }

src/test/test-copy.c

@@ -560,7 +560,7 @@ TEST(copy_lock) {
         assert_se(mkdirat(tfd, "abc", 0755) >= 0);
         assert_se(write_string_file_at(tfd, "abc/def", "abc", WRITE_STRING_FILE_CREATE) >= 0);
 
-        assert_se((fd = copy_directory_at(tfd, "abc", tfd, "qed", COPY_LOCK_BSD)) >= 0);
+        assert_se((fd = copy_directory_at(tfd, "abc", tfd, "qed", UID_INVALID, GID_INVALID, COPY_LOCK_BSD)) >= 0);
         assert_se(faccessat(tfd, "qed", F_OK, 0) >= 0);
         assert_se(faccessat(tfd, "qed/def", F_OK, 0) >= 0);
         assert_se(xopenat_lock(tfd, "qed", 0, LOCK_BSD, LOCK_EX|LOCK_NB) == -EAGAIN);

src/test/test-execute.c

@@ -1497,7 +1497,7 @@ static int prepare_ns(const char *process_name) {
 
                 /* Copy unit files to make them accessible even when unprivileged. */
                 ASSERT_OK(get_testdata_dir("test-execute/", &unit_dir));
-                ASSERT_OK(copy_directory_at(AT_FDCWD, unit_dir, AT_FDCWD, PRIVATE_UNIT_DIR, COPY_MERGE_EMPTY));
+                ASSERT_OK(copy_directory_at(AT_FDCWD, unit_dir, AT_FDCWD, PRIVATE_UNIT_DIR, UID_INVALID, GID_INVALID, COPY_MERGE_EMPTY));
 
                 /* Mount tmpfs on the following directories to make not StateDirectory= or friends disturb the host. */
                 ASSERT_OK_OR(get_build_exec_dir(&build_dir), -ENOEXEC);

test/units/TEST-50-DISSECT.dissect.sh

@@ -1050,6 +1050,45 @@ echo abc >abc
 systemd-dissect --copy-to /tmp/img abc /abc
 test -f /tmp/img/abc
 
+# Test --copy-ownership= option
+rm -rf /tmp/copychown-test
+mkdir -p /tmp/copychown-test/srcdir
+echo "test file" >/tmp/copychown-test/srcdir/testfile
+chown 1234:5678 /tmp/copychown-test/srcdir/testfile
+chown 1234:5678 /tmp/copychown-test/srcdir
+
+# Test --copy-ownership=yes preserves ownership for regular files
+systemd-dissect --copy-from /tmp/img etc/os-release /tmp/copychown-test/os-release-chown-yes --copy-ownership=yes
+test "$(stat -c %u:%g /tmp/copychown-test/os-release-chown-yes)" = "0:0"
+
+# Test --copy-ownership=no uses current user for regular files
+systemd-dissect --copy-from /tmp/img etc/os-release /tmp/copychown-test/os-release-chown-no --copy-ownership=no
+test "$(stat -c %u:%g /tmp/copychown-test/os-release-chown-no)" = "0:0"
+
+# Test --copy-ownership=auto (default) does not preserve ownership for regular files
+systemd-dissect --copy-from /tmp/img etc/os-release /tmp/copychown-test/os-release-chown-auto
+test "$(stat -c %u:%g /tmp/copychown-test/os-release-chown-auto)" = "0:0"
+
+# Test --copy-ownership=yes preserves ownership for directories
+systemd-dissect --copy-to /tmp/img /tmp/copychown-test/srcdir /copychown-dir-yes --copy-ownership=yes
+test "$(stat -c %u:%g /tmp/img/copychown-dir-yes)" = "1234:5678"
+test "$(stat -c %u:%g /tmp/img/copychown-dir-yes/testfile)" = "1234:5678"
+rm -rf /tmp/img/copychown-dir-yes
+
+# Test --copy-ownership=no overrides ownership for directories
+systemd-dissect --copy-to /tmp/img /tmp/copychown-test/srcdir /copychown-dir-no --copy-ownership=no
+test "$(stat -c %u:%g /tmp/img/copychown-dir-no)" = "0:0"
+test "$(stat -c %u:%g /tmp/img/copychown-dir-no/testfile)" = "0:0"
+rm -rf /tmp/img/copychown-dir-no
+
+# Test --copy-ownership=auto (default) preserves ownership for directories
+systemd-dissect --copy-to /tmp/img /tmp/copychown-test/srcdir /copychown-dir-auto
+test "$(stat -c %u:%g /tmp/img/copychown-dir-auto)" = "1234:5678"
+test "$(stat -c %u:%g /tmp/img/copychown-dir-auto/testfile)" = "1234:5678"
+rm -rf /tmp/img/copychown-dir-auto
+
+rm -rf /tmp/copychown-test
+
 # Test for dissect tool support with systemd-sysext
 mkdir -p /run/extensions/ testkit/usr/lib/extension-release.d/
 echo "ID=_any" >testkit/usr/lib/extension-release.d/extension-release.testkit