Merge 4baee2d732 into c946b13575

The file README.logs is installed only if SysVInit support is enabled.
Thus the link should depend on it as well.

hwdb.d/60-sensor.hwdb

@@ -953,6 +953,15 @@ sensor:modalias:acpi:MXC6655*:dmi:*:svnDefaultstring*:pnP612F:*
 sensor:modalias:acpi:SMO8500*:dmi:*:svnPEAQ:pnPEAQPMMC1010MD99187:*
  ACCEL_MOUNT_MATRIX=-1, 0, 0; 0, 1, 0; 0, 0, 1
 
+#########################################
+# Pine64
+#########################################
+
+# PineTab2
+
+sensor:modalias:of:NaccelerometerT_null_Csilan,sc7a20:*
+ ACCEL_MOUNT_MATRIX=0, 0, -1; 1, 0, 0; 0, -1, 0
+
 #########################################
 # Pipo
 #########################################

src/basic/cgroup-util.c

@@ -1418,6 +1418,26 @@ int cg_pid_get_session(pid_t pid, char **ret_session) {
         return cg_path_get_session(cgroup, ret_session);
 }
 
+int cg_pidref_get_session(const PidRef *pidref, char **ret) {
+        int r;
+
+        if (!pidref_is_set(pidref))
+                return -ESRCH;
+
+        _cleanup_free_ char *session = NULL;
+        r = cg_pid_get_session(pidref->pid, &session);
+        if (r < 0)
+                return r;
+
+        r = pidref_verify(pidref);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = TAKE_PTR(session);
+        return 0;
+}
+
 int cg_path_get_owner_uid(const char *path, uid_t *ret_uid) {
         _cleanup_free_ char *slice = NULL;
         char *start, *end;
@@ -1455,6 +1475,27 @@ int cg_pid_get_owner_uid(pid_t pid, uid_t *ret_uid) {
         return cg_path_get_owner_uid(cgroup, ret_uid);
 }
 
+int cg_pidref_get_owner_uid(const PidRef *pidref, uid_t *ret) {
+        int r;
+
+        if (!pidref_is_set(pidref))
+                return -ESRCH;
+
+        uid_t uid;
+        r = cg_pid_get_owner_uid(pidref->pid, &uid);
+        if (r < 0)
+                return r;
+
+        r = pidref_verify(pidref);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = uid;
+
+        return 0;
+}
+
 int cg_path_get_slice(const char *p, char **ret_slice) {
         const char *e = NULL;
 

src/basic/cgroup-util.h

@@ -280,7 +280,9 @@ int cg_shift_path(const char *cgroup, const char *cached_root, const char **ret_
 int cg_pid_get_path_shifted(pid_t pid, const char *cached_root, char **ret_cgroup);
 
 int cg_pid_get_session(pid_t pid, char **ret_session);
+int cg_pidref_get_session(const PidRef *pidref, char **ret_session);
 int cg_pid_get_owner_uid(pid_t pid, uid_t *ret_uid);
+int cg_pidref_get_owner_uid(const PidRef *pidref, uid_t *ret_uid);
 int cg_pid_get_unit(pid_t pid, char **ret_unit);
 int cg_pidref_get_unit(const PidRef *pidref, char **ret);
 int cg_pid_get_user_unit(pid_t pid, char **ret_unit);

src/basic/pidref.c

@@ -429,7 +429,7 @@ int pidref_wait(const PidRef *pidref, siginfo_t *ret, int options) {
         if (pidref_is_remote(pidref))
                 return -EREMOTE;
 
-        if (pidref->pid == 1 || pidref->pid == getpid_cached())
+        if (pidref->pid == 1 || pidref_is_self(pidref))
                 return -ECHILD;
 
         siginfo_t si = {};

src/basic/socket-util.c

@@ -975,6 +975,28 @@ int getpeerpidfd(int fd) {
         return pidfd;
 }
 
+int getpeerpidref(int fd, PidRef *ret) {
+        int r;
+
+        assert(fd >= 0);
+        assert(ret);
+
+        int pidfd = getpeerpidfd(fd);
+        if (pidfd < 0)  {
+                if (!ERRNO_IS_NEG_NOT_SUPPORTED(pidfd) && pidfd != -EINVAL)
+                        return pidfd;
+
+                struct ucred ucred;
+                r = getpeercred(fd, &ucred);
+                if (r < 0)
+                        return r;
+
+                return pidref_set_pid(ret, ucred.pid);
+        }
+
+        return pidref_set_pidfd_consume(ret, pidfd);
+}
+
 ssize_t send_many_fds_iov_sa(
                 int transport_fd,
                 int *fds_array, size_t n_fds_array,

src/basic/socket-util.h

@@ -20,6 +20,7 @@
 #include "macro.h"
 #include "missing_network.h"
 #include "missing_socket.h"
+#include "pidref.h"
 #include "sparse-endian.h"
 
 union sockaddr_union {
@@ -154,6 +155,7 @@ int getpeercred(int fd, struct ucred *ucred);
 int getpeersec(int fd, char **ret);
 int getpeergroups(int fd, gid_t **ret);
 int getpeerpidfd(int fd);
+int getpeerpidref(int fd, PidRef *ret);
 
 ssize_t send_many_fds_iov_sa(
                 int transport_fd,

src/basic/terminal-util.c

@@ -761,26 +761,24 @@ bool tty_is_console(const char *tty) {
 }
 
 int vtnr_from_tty(const char *tty) {
-        int i, r;
+        int r;
 
         assert(tty);
 
         tty = skip_dev_prefix(tty);
 
-        if (!startswith(tty, "tty") )
+        const char *e = startswith(tty, "tty");
+        if (!e)
                 return -EINVAL;
 
-        if (!ascii_isdigit(tty[3]))
+        unsigned u;
-                return -EINVAL;
+        r = safe_atou(e, &u);
-
-        r = safe_atoi(tty+3, &i);
         if (r < 0)
                 return r;
+        if (!vtnr_is_valid(u))
+                return -ERANGE;
 
-        if (i < 0 || i > 63)
+        return (int) u;
-                return -EINVAL;
-
-        return i;
 }
 
 int resolve_dev_console(char **ret) {

src/basic/terminal-util.h

@@ -157,3 +157,7 @@ int terminal_is_pty_fd(int fd);
 
 int pty_open_peer_racefree(int fd, int mode);
 int pty_open_peer(int fd, int mode);
+
+static inline bool vtnr_is_valid(unsigned n) {
+        return n >= 1 && n <= 63;
+}

src/libsystemd/sd-bus/test-bus-peersockaddr.c

@@ -81,7 +81,7 @@ static void *server(void *p) {
                 _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
 
                 assert_se(pidref_set_pidfd_take(&pidref, pidfd) >= 0);
-                assert_se(pidref.pid == getpid_cached());
+                assert_se(pidref_is_self(&pidref));
         }
 
         const gid_t *gl = NULL;

src/libsystemd/sd-json/json-util.c

@@ -125,14 +125,13 @@ int json_dispatch_in_addr(const char *name, sd_json_variant *variant, sd_json_di
         return 0;
 }
 
-int json_dispatch_path(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata) {
+int json_dispatch_const_path(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata) {
-        char **p = ASSERT_PTR(userdata);
+        const char **p = ASSERT_PTR(userdata), *path;
-        const char *path;
 
         assert(variant);
 
         if (sd_json_variant_is_null(variant)) {
-                *p = mfree(*p);
+                *p = NULL;
                 return 0;
         }
 
@@ -145,8 +144,24 @@ int json_dispatch_path(const char *name, sd_json_variant *variant, sd_json_dispa
         if (!path_is_absolute(path))
                 return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' is not an absolute file system path.", strna(name));
 
-        if (free_and_strdup(p, path) < 0)
+        *p = path;
-                return json_log_oom(variant, flags);
+        return 0;
+}
+
+int json_dispatch_path(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata) {
+        char **s = ASSERT_PTR(userdata);
+        const char *p;
+        int r;
+
+        assert_return(variant, -EINVAL);
+
+        r = json_dispatch_const_path(name, variant, flags, &p);
+        if (r < 0)
+                return r;
+
+        r = free_and_strdup(s, p);
+        if (r < 0)
+                return json_log(variant, flags, r, "Failed to allocate path string: %m");
 
         return 0;
 }

src/libsystemd/sd-json/json-util.h

@@ -113,6 +113,7 @@ int json_dispatch_user_group_name(const char *name, sd_json_variant *variant, sd
 int json_dispatch_const_user_group_name(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
 int json_dispatch_in_addr(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
 int json_dispatch_path(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
+int json_dispatch_const_path(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
 int json_dispatch_pidref(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
 int json_dispatch_devnum(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
 int json_dispatch_ifindex(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);

src/libsystemd/sd-login/sd-login.c

@@ -334,46 +334,46 @@ _public_ int sd_pidfd_get_cgroup(int pidfd, char **ret_cgroup) {
         return 0;
 }
 
-_public_ int sd_peer_get_session(int fd, char **session) {
+_public_ int sd_peer_get_session(int fd, char **ret) {
-        struct ucred ucred = UCRED_INVALID;
         int r;
 
         assert_return(fd >= 0, -EBADF);
-        assert_return(session, -EINVAL);
+        assert_return(ret, -EINVAL);
 
-        r = getpeercred(fd, &ucred);
+        _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
+        r = getpeerpidref(fd, &pidref);
         if (r < 0)
                 return r;
 
-        return cg_pid_get_session(ucred.pid, session);
+        return cg_pidref_get_session(&pidref, ret);
 }
 
-_public_ int sd_peer_get_owner_uid(int fd, uid_t *uid) {
+_public_ int sd_peer_get_owner_uid(int fd, uid_t *ret) {
-        struct ucred ucred;
         int r;
 
         assert_return(fd >= 0, -EBADF);
-        assert_return(uid, -EINVAL);
+        assert_return(ret, -EINVAL);
 
-        r = getpeercred(fd, &ucred);
+        _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
+        r = getpeerpidref(fd, &pidref);
         if (r < 0)
                 return r;
 
-        return cg_pid_get_owner_uid(ucred.pid, uid);
+        return cg_pidref_get_owner_uid(&pidref, ret);
 }
 
-_public_ int sd_peer_get_unit(int fd, char **unit) {
+_public_ int sd_peer_get_unit(int fd, char **ret) {
-        struct ucred ucred;
         int r;
 
         assert_return(fd >= 0, -EBADF);
-        assert_return(unit, -EINVAL);
+        assert_return(ret, -EINVAL);
 
-        r = getpeercred(fd, &ucred);
+        _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
+        r = getpeerpidref(fd, &pidref);
         if (r < 0)
                 return r;
 
-        return cg_pid_get_unit(ucred.pid, unit);
+        return cg_pidref_get_unit(&pidref, ret);
 }
 
 _public_ int sd_peer_get_user_unit(int fd, char **unit) {

src/libsystemd/sd-varlink/sd-varlink.c

@@ -1698,7 +1698,8 @@ _public_ int sd_varlink_get_events(sd_varlink *v) {
                 ret |= EPOLLIN;
 
         if (!v->write_disconnected &&
-            v->output_buffer_size > 0)
+            (v->output_queue ||
+             v->output_buffer_size > 0))
                 ret |= EPOLLOUT;
 
         return ret;
@@ -3218,7 +3219,13 @@ _public_ int sd_varlink_server_new(sd_varlink_server **ret, sd_varlink_server_fl
         int r;
 
         assert_return(ret, -EINVAL);
-        assert_return((flags & ~(SD_VARLINK_SERVER_ROOT_ONLY|SD_VARLINK_SERVER_MYSELF_ONLY|SD_VARLINK_SERVER_ACCOUNT_UID|SD_VARLINK_SERVER_INHERIT_USERDATA|SD_VARLINK_SERVER_INPUT_SENSITIVE)) == 0, -EINVAL);
+        assert_return((flags & ~(SD_VARLINK_SERVER_ROOT_ONLY|
+                                 SD_VARLINK_SERVER_MYSELF_ONLY|
+                                 SD_VARLINK_SERVER_ACCOUNT_UID|
+                                 SD_VARLINK_SERVER_INHERIT_USERDATA|
+                                 SD_VARLINK_SERVER_INPUT_SENSITIVE|
+                                 SD_VARLINK_SERVER_ALLOW_FD_PASSING_INPUT|
+                                 SD_VARLINK_SERVER_ALLOW_FD_PASSING_OUTPUT)) == 0, -EINVAL);
 
         s = new(sd_varlink_server, 1);
         if (!s)
@@ -3399,6 +3406,9 @@ _public_ int sd_varlink_server_add_connection_pair(
         if (asprintf(&desc, "%s-%i-%i", varlink_server_description(server), input_fd, output_fd) >= 0)
                 v->description = TAKE_PTR(desc);
 
+        (void) sd_varlink_set_allow_fd_passing_input(v, FLAGS_SET(server->flags, SD_VARLINK_SERVER_ALLOW_FD_PASSING_INPUT));
+        (void) sd_varlink_set_allow_fd_passing_output(v, FLAGS_SET(server->flags, SD_VARLINK_SERVER_ALLOW_FD_PASSING_OUTPUT));
+
         /* Link up the server and the connection, and take reference in both directions. Note that the
          * reference on the connection is left dangling. It will be dropped when the connection is closed,
          * which happens in varlink_close(), including in the event loop quit callback. */

src/libsystemd/sd-varlink/varlink-util.c

@@ -16,7 +16,7 @@ int varlink_get_peer_pidref(sd_varlink *v, PidRef *ret) {
 
         int pidfd = sd_varlink_get_peer_pidfd(v);
         if (pidfd < 0) {
-                if (!ERRNO_IS_NEG_NOT_SUPPORTED(pidfd))
+                if (!ERRNO_IS_NEG_NOT_SUPPORTED(pidfd) && pidfd != -EINVAL)
                         return pidfd;
 
                 pid_t pid;

src/login/logind-dbus.c

@@ -85,6 +85,8 @@ static int get_sender_session(
         const char *name;
         int r;
 
+        assert(m);
+
         /* Acquire the sender's session. This first checks if the sending process is inside a session itself,
          * and returns that. If not and 'consult_display' is true, this returns the display session of the
          * owning user of the caller. */
@@ -827,189 +829,24 @@ static int method_list_inhibitors(sd_bus_message *message, void *userdata, sd_bu
         return sd_bus_send(NULL, reply, NULL);
 }
 
-static int create_session(
+static int manager_choose_session_id(
-                sd_bus_message *message,
+                Manager *m,
-                void *userdata,
+                PidRef *leader,
-                sd_bus_error *error,
+                char **ret_id) {
-                uid_t uid,
-                pid_t leader_pid,
-                int leader_pidfd,
-                const char *service,
-                const char *type,
-                const char *class,
-                const char *desktop,
-                const char *cseat,
-                uint32_t vtnr,
-                const char *tty,
-                const char *display,
-                int remote,
-                const char *remote_user,
-                const char *remote_host,
-                uint64_t flags) {
 
-        _cleanup_(pidref_done) PidRef leader = PIDREF_NULL;
-        Manager *m = ASSERT_PTR(userdata);
-        _cleanup_free_ char *id = NULL;
-        Session *session = NULL;
-        uint32_t audit_id = 0;
-        User *user = NULL;
-        Seat *seat = NULL;
-        SessionType t;
-        SessionClass c;
         int r;
 
-        assert(message);
+        assert(m);
+        assert(pidref_is_set(leader));
+        assert(ret_id);
 
-        if (!uid_is_valid(uid))
+        /* Try to keep our session IDs and the audit session IDs in sync */
-                return sd_bus_error_set(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid UID");
+        _cleanup_free_ char *id = NULL;
-
+        uint32_t audit_id = AUDIT_SESSION_INVALID;
-        if (flags != 0)
+        r = audit_session_from_pid(leader, &audit_id);
-                return sd_bus_error_set(error, SD_BUS_ERROR_INVALID_ARGS, "Flags must be zero.");
-
-        if (leader_pidfd >= 0)
-                r = pidref_set_pidfd(&leader, leader_pidfd);
-        else if (leader_pid == 0)
-                r = bus_query_sender_pidref(message, &leader);
-        else {
-                if (leader_pid < 0)
-                        return sd_bus_error_set(error, SD_BUS_ERROR_INVALID_ARGS, "Leader PID is not valid");
-
-                r = pidref_set_pid(&leader, leader_pid);
-        }
         if (r < 0)
-                return r;
+                log_debug_errno(r, "Failed to read audit session ID of process " PID_FMT ", ignoring: %m", leader->pid);
-
-        if (leader.pid == 1 || leader.pid == getpid_cached())
-                return sd_bus_error_set(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid leader PID");
-
-        if (isempty(type))
-                t = _SESSION_TYPE_INVALID;
         else {
-                t = session_type_from_string(type);
-                if (t < 0)
-                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
-                                                 "Invalid session type %s", type);
-        }
-
-        if (isempty(class))
-                c = _SESSION_CLASS_INVALID;
-        else {
-                c = session_class_from_string(class);
-                if (c < 0)
-                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
-                                                 "Invalid session class %s", class);
-        }
-
-        if (isempty(desktop))
-                desktop = NULL;
-        else {
-                if (!string_is_safe(desktop))
-                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
-                                                 "Invalid desktop string %s", desktop);
-        }
-
-        if (isempty(cseat))
-                seat = NULL;
-        else {
-                seat = hashmap_get(m->seats, cseat);
-                if (!seat)
-                        return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SEAT,
-                                                 "No seat '%s' known", cseat);
-        }
-
-        if (tty_is_vc(tty)) {
-                int v;
-
-                if (!seat)
-                        seat = m->seat0;
-                else if (seat != m->seat0)
-                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
-                                                 "TTY %s is virtual console but seat %s is not seat0", tty, seat->id);
-
-                v = vtnr_from_tty(tty);
-                if (v <= 0)
-                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
-                                                 "Cannot determine VT number from virtual console TTY %s", tty);
-
-                if (vtnr == 0)
-                        vtnr = (uint32_t) v;
-                else if (vtnr != (uint32_t) v)
-                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
-                                                 "Specified TTY and VT number do not match");
-
-        } else if (tty_is_console(tty)) {
-
-                if (!seat)
-                        seat = m->seat0;
-                else if (seat != m->seat0)
-                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
-                                                 "Console TTY specified but seat is not seat0");
-
-                if (vtnr != 0)
-                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
-                                                 "Console TTY specified but VT number is not 0");
-        }
-
-        if (seat) {
-                if (seat_has_vts(seat)) {
-                        if (vtnr <= 0 || vtnr > 63)
-                                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
-                                                         "VT number out of range");
-                } else {
-                        if (vtnr != 0)
-                                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
-                                                         "Seat has no VTs but VT number not 0");
-                }
-        }
-
-        if (t == _SESSION_TYPE_INVALID) {
-                if (!isempty(display))
-                        t = SESSION_X11;
-                else if (!isempty(tty))
-                        t = SESSION_TTY;
-                else
-                        t = SESSION_UNSPECIFIED;
-        }
-
-        if (c == _SESSION_CLASS_INVALID) {
-                if (t == SESSION_UNSPECIFIED)
-                        c = SESSION_BACKGROUND;
-                else
-                        c = SESSION_USER;
-        }
-
-        /* Check if we are already in a logind session, and if so refuse. */
-        r = manager_get_session_by_pidref(m, &leader, /* ret_session= */ NULL);
-        if (r < 0)
-                return log_debug_errno(
-                                r,
-                                "Failed to check if process " PID_FMT " is already in a session: %m",
-                                leader.pid);
-        if (r > 0)
-                return sd_bus_error_setf(error, BUS_ERROR_SESSION_BUSY,
-                                         "Already running in a session or user slice");
-
-        /* Old gdm and lightdm start the user-session on the same VT as the greeter session. But they destroy
-         * the greeter session after the user-session and want the user-session to take over the VT. We need
-         * to support this for backwards-compatibility, so make sure we allow new sessions on a VT that a
-         * greeter is running on. Furthermore, to allow re-logins, we have to allow a greeter to take over a
-         * used VT for the exact same reasons. */
-        if (c != SESSION_GREETER &&
-            vtnr > 0 &&
-            vtnr < MALLOC_ELEMENTSOF(m->seat0->positions) &&
-            m->seat0->positions[vtnr] &&
-            m->seat0->positions[vtnr]->class != SESSION_GREETER)
-                return sd_bus_error_set(error, BUS_ERROR_SESSION_BUSY, "Already occupied by a session");
-
-        if (hashmap_size(m->sessions) >= m->sessions_max)
-                return sd_bus_error_setf(error, SD_BUS_ERROR_LIMITS_EXCEEDED,
-                                         "Maximum number of sessions (%" PRIu64 ") reached, refusing further sessions.",
-                                         m->sessions_max);
-
-        (void) audit_session_from_pid(&leader, &audit_id);
-        if (audit_session_is_valid(audit_id)) {
-                /* Keep our session IDs and the audit session IDs in sync */
-
                 if (asprintf(&id, "%"PRIu32, audit_id) < 0)
                         return -ENOMEM;
 
@@ -1017,12 +854,11 @@ static int create_session(
                  * not trust the audit data and let's better register a new ID */
                 if (hashmap_contains(m->sessions, id)) {
                         log_warning("Existing logind session ID %s used by new audit session, ignoring.", id);
-                        audit_id = AUDIT_SESSION_INVALID;
                         id = mfree(id);
                 }
         }
 
-        if (!id) {
+        if (!id)
                 do {
                         id = mfree(id);
 
@@ -1030,15 +866,97 @@ static int create_session(
                                 return -ENOMEM;
 
                 } while (hashmap_contains(m->sessions, id));
-        }
 
         /* The generated names should not clash with 'auto' or 'self' */
         assert(!SESSION_IS_SELF(id));
         assert(!SESSION_IS_AUTO(id));
 
+        *ret_id = TAKE_PTR(id);
+        return 0;
+}
+
+int manager_create_session(
+                Manager *m,
+                uid_t uid,
+                PidRef *leader, /* consumed */
+                const char *service,
+                SessionType type,
+                SessionClass class,
+                const char *desktop,
+                Seat *seat,
+                unsigned vtnr,
+                const char *tty,
+                const char *display,
+                bool remote,
+                const char *remote_user,
+                const char *remote_host,
+                Session **ret_session) {
+
+        int r;
+
+        assert(m);
+        assert(uid_is_valid(uid));
+        assert(pidref_is_set(leader));
+        assert(ret_session);
+
+        /* Returns:
+         *    -EBUSY         → client is already in a session
+         *    -EADDRNOTAVAIL → VT is already taken
+         *    -EUSERS        → limit of sessions reached
+         */
+
+        if (type == _SESSION_TYPE_INVALID) {
+                if (!isempty(display))
+                        type = SESSION_X11;
+                else if (!isempty(tty))
+                        type = SESSION_TTY;
+                else
+                        type = SESSION_UNSPECIFIED;
+        }
+
+        if (class == _SESSION_CLASS_INVALID) {
+                if (type == SESSION_UNSPECIFIED)
+                        class = SESSION_BACKGROUND;
+                else
+                        class = SESSION_USER;
+        }
+
+        /* Check if we are already in a logind session, and if so refuse. */
+        r = manager_get_session_by_pidref(m, leader, /* ret_session= */ NULL);
+        if (r < 0)
+                return log_debug_errno(
+                                r,
+                                "Failed to check if process " PID_FMT " is already in a session: %m",
+                                leader->pid);
+        if (r > 0)
+                return log_debug_errno(SYNTHETIC_ERRNO(EBUSY), "Client is already in a session.");
+
+        /* Old gdm and lightdm start the user-session on the same VT as the greeter session. But they destroy
+         * the greeter session after the user-session and want the user-session to take over the VT. We need
+         * to support this for backwards-compatibility, so make sure we allow new sessions on a VT that a
+         * greeter is running on. Furthermore, to allow re-logins, we have to allow a greeter to take over a
+         * used VT for the exact same reasons. */
+        if (class != SESSION_GREETER &&
+            vtnr > 0 &&
+            vtnr < MALLOC_ELEMENTSOF(m->seat0->positions) &&
+            m->seat0->positions[vtnr] &&
+            m->seat0->positions[vtnr]->class != SESSION_GREETER)
+                return log_debug_errno(SYNTHETIC_ERRNO(EADDRNOTAVAIL), "VT already occupied by a session.");
+
+        if (hashmap_size(m->sessions) >= m->sessions_max)
+                return log_debug_errno(SYNTHETIC_ERRNO(EUSERS), "Maximum number of sessions (%" PRIu64 ") reached, refusing further sessions.", m->sessions_max);
+
+        _cleanup_free_ char *id = NULL;
+        r = manager_choose_session_id(m, leader, &id);
+        if (r < 0)
+                return r;
+
         /* If we are not watching utmp already, try again */
         manager_reconnect_utmp(m);
 
+        User *user = NULL;
+        Session *session = NULL;
+
         r = manager_add_user_by_uid(m, uid, &user);
         if (r < 0)
                 goto fail;
@@ -1048,21 +966,21 @@ static int create_session(
                 goto fail;
 
         session_set_user(session, user);
-        r = session_set_leader_consume(session, TAKE_PIDREF(leader));
+        r = session_set_leader_consume(session, TAKE_PIDREF(*leader));
         if (r < 0)
                 goto fail;
 
-        session->original_type = session->type = t;
+        session->original_type = session->type = type;
         session->remote = remote;
         session->vtnr = vtnr;
-        session->class = c;
+        session->class = class;
 
         /* Once the first session that is of a pinning class shows up we'll change the GC mode for the user
          * from USER_GC_BY_ANY to USER_GC_BY_PIN, so that the user goes away once the last pinning session
          * goes away. Background: we want that user@.service – when started manually – remains around (which
          * itself is a non-pinning session), but gets stopped when the last pinning session goes away. */
 
-        if (SESSION_CLASS_PIN_USER(c))
+        if (SESSION_CLASS_PIN_USER(class))
                 user->gc_mode = USER_GC_BY_PIN;
 
         if (!isempty(tty)) {
@@ -1109,14 +1027,184 @@ static int create_session(
                         goto fail;
         }
 
+        *ret_session = session;
+        return 0;
+
+fail:
+        if (session)
+                session_add_to_gc_queue(session);
+
+        if (user)
+                user_add_to_gc_queue(user);
+
+        return r;
+}
+
+static int manager_create_session_by_bus(
+                Manager *m,
+                sd_bus_message *message,
+                sd_bus_error *error,
+                uid_t uid,
+                pid_t leader_pid,
+                int leader_pidfd,
+                const char *service,
+                const char *type,
+                const char *class,
+                const char *desktop,
+                const char *cseat,
+                uint32_t vtnr,
+                const char *tty,
+                const char *display,
+                int remote,
+                const char *remote_user,
+                const char *remote_host,
+                uint64_t flags) {
+
+        int r;
+
+        assert(m);
+        assert(message);
+
+        if (!uid_is_valid(uid))
+                return sd_bus_error_set(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid UID");
+
+        if (flags != 0)
+                return sd_bus_error_set(error, SD_BUS_ERROR_INVALID_ARGS, "Flags must be zero.");
+
+        _cleanup_(pidref_done) PidRef leader = PIDREF_NULL;
+        if (leader_pidfd >= 0)
+                r = pidref_set_pidfd(&leader, leader_pidfd);
+        else if (leader_pid == 0)
+                r = bus_query_sender_pidref(message, &leader);
+        else {
+                if (leader_pid < 0)
+                        return sd_bus_error_set(error, SD_BUS_ERROR_INVALID_ARGS, "Leader PID is not valid");
+
+                r = pidref_set_pid(&leader, leader_pid);
+        }
+        if (r < 0)
+                return r;
+
+        if (leader.pid == 1 || pidref_is_self(&leader))
+                return sd_bus_error_set(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid leader PID");
+
+        SessionType t;
+        if (isempty(type))
+                t = _SESSION_TYPE_INVALID;
+        else {
+                t = session_type_from_string(type);
+                if (t < 0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                                                 "Invalid session type %s", type);
+        }
+
+        SessionClass c;
+        if (isempty(class))
+                c = _SESSION_CLASS_INVALID;
+        else {
+                c = session_class_from_string(class);
+                if (c < 0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                                                 "Invalid session class %s", class);
+        }
+
+        if (isempty(desktop))
+                desktop = NULL;
+        else {
+                if (!string_is_safe(desktop))
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                                                 "Invalid desktop string %s", desktop);
+        }
+
+        Seat *seat = NULL;
+        if (isempty(cseat))
+                seat = NULL;
+        else {
+                seat = hashmap_get(m->seats, cseat);
+                if (!seat)
+                        return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SEAT,
+                                                 "No seat '%s' known", cseat);
+        }
+
+        if (isempty(tty))
+                tty = NULL;
+        else if (tty_is_vc(tty)) {
+                int v;
+
+                if (!seat)
+                        seat = m->seat0;
+                else if (seat != m->seat0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                                                 "TTY %s is virtual console but seat %s is not seat0", tty, seat->id);
+
+                v = vtnr_from_tty(tty);
+                if (v <= 0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                                                 "Cannot determine VT number from virtual console TTY %s", tty);
+
+                if (vtnr == 0)
+                        vtnr = (uint32_t) v;
+                else if (vtnr != (uint32_t) v)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                                                 "Specified TTY and VT number do not match");
+
+        } else if (tty_is_console(tty)) {
+
+                if (!seat)
+                        seat = m->seat0;
+                else if (seat != m->seat0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                                                 "Console TTY specified but seat is not seat0");
+
+                if (vtnr != 0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                                                 "Console TTY specified but VT number is not 0");
+        }
+
+        if (seat) {
+                if (seat_has_vts(seat)) {
+                        if (!vtnr_is_valid(vtnr))
+                                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                                                         "VT number out of range");
+                } else {
+                        if (vtnr != 0)
+                                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                                                         "Seat has no VTs but VT number not 0");
+                }
+        }
+
+        Session *session;
+        r = manager_create_session(
+                        m,
+                        uid,
+                        &leader,
+                        service,
+                        t,
+                        c,
+                        desktop,
+                        seat,
+                        vtnr,
+                        tty,
+                        display,
+                        remote,
+                        remote_user,
+                        remote_host,
+                        &session);
+        if (r == -EBUSY)
+                return sd_bus_error_setf(error, BUS_ERROR_SESSION_BUSY, "Already running in a session or user slice");
+        if (r == -EADDRNOTAVAIL)
+                return sd_bus_error_set(error, BUS_ERROR_SESSION_BUSY, "Virtual terminal already occupied by a session");
+        if (r == -EUSERS)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_LIMITS_EXCEEDED, "Maximum number of sessions (%" PRIu64 ") reached, refusing further sessions.", m->sessions_max);
+        if (r < 0)
+                return r;
+
         r = sd_bus_message_enter_container(message, 'a', "(sv)");
         if (r < 0)
                 goto fail;
-
         r = session_start(session, message, error);
         if (r < 0)
                 goto fail;
-
         r = sd_bus_message_exit_container(message);
         if (r < 0)
                 goto fail;
@@ -1130,7 +1218,7 @@ static int create_session(
          * all is complete - or wait again. */
         r = session_send_create_reply(session, /* error= */ NULL);
         if (r < 0)
-                return r;
+                goto fail;
 
         return 1;
 
@@ -1138,9 +1226,6 @@ fail:
         if (session)
                 session_add_to_gc_queue(session);
 
-        if (user)
-                user_add_to_gc_queue(user);
-
         return r;
 }
 
@@ -1175,9 +1260,9 @@ static int method_create_session(sd_bus_message *message, void *userdata, sd_bus
         if (r < 0)
                 return r;
 
-        return create_session(
+        return manager_create_session_by_bus(
-                        message,
                         userdata,
+                        message,
                         error,
                         uid,
                         leader_pid,
@@ -1223,9 +1308,9 @@ static int method_create_session_pidfd(sd_bus_message *message, void *userdata,
         if (r < 0)
                 return r;
 
-        return create_session(
+        return manager_create_session_by_bus(
-                        message,
                         userdata,
+                        message,
                         error,
                         uid,
                         /* leader_pid = */ 0,

src/login/logind-dbus.h

@@ -47,4 +47,21 @@ int manager_job_is_active(Manager *manager, const char *path, sd_bus_error *erro
 
 void manager_load_scheduled_shutdown(Manager *m);
 
+int manager_create_session(
+                Manager *m,
+                uid_t uid,
+                PidRef *leader,
+                const char *service,
+                SessionType type,
+                SessionClass class,
+                const char *desktop,
+                Seat *seat,
+                unsigned vtnr,
+                const char *tty,
+                const char *display,
+                bool remote,
+                const char *remote_user,
+                const char *remote_host,
+                Session **ret_session);
+
 extern const BusObjectImplementation manager_object;

src/login/logind-session-dbus.c

@@ -899,62 +899,40 @@ int session_send_lock_all(Manager *m, bool lock) {
         return r;
 }
 
-static bool session_job_pending(Session *s) {
+int session_send_create_reply_bus(Session *s, const sd_bus_error *error) {
-        assert(s);
-        assert(s->user);
-
-        /* Check if we have some jobs enqueued and not finished yet. Each time we get JobRemoved signal about
-         * relevant units, session_send_create_reply and hence us is called (see match_job_removed).
-         * Note that we don't care about job result here. */
-
-        return s->scope_job ||
-               s->user->runtime_dir_job ||
-               (SESSION_CLASS_WANTS_SERVICE_MANAGER(s->class) && s->user->service_manager_job);
-}
-
-int session_send_create_reply(Session *s, sd_bus_error *error) {
-        _cleanup_(sd_bus_message_unrefp) sd_bus_message *c = NULL;
-        _cleanup_close_ int fifo_fd = -EBADF;
-        _cleanup_free_ char *p = NULL;
-
         assert(s);
 
-        /* This is called after the session scope and the user service were successfully created, and finishes where
+        /* This is called after the session scope and the user service were successfully created, and
-         * bus_manager_create_session() left off. */
+         * finishes where manager_create_session() left off. */
 
-        if (!s->create_message)
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *c = TAKE_PTR(s->create_message);
+        if (!c)
                 return 0;
 
-        /* If error occurred, return it immediately. Otherwise let's wait for all jobs to finish before
+        if (sd_bus_error_is_set(error))
-         * continuing. */
-        if (!sd_bus_error_is_set(error) && session_job_pending(s))
-                return 0;
-
-        c = TAKE_PTR(s->create_message);
-        if (error)
                 return sd_bus_reply_method_error(c, error);
 
-        fifo_fd = session_create_fifo(s);
+        _cleanup_close_ int fifo_fd = session_create_fifo(s);
         if (fifo_fd < 0)
                 return fifo_fd;
 
         /* Update the session state file before we notify the client about the result. */
         session_save(s);
 
-        p = session_bus_path(s);
+        _cleanup_free_ char *p = session_bus_path(s);
         if (!p)
                 return -ENOMEM;
 
-        log_debug("Sending reply about created session: "
+        log_debug("Sending D-Bus reply about created session: "
-                  "id=%s object_path=%s uid=%u runtime_path=%s "
+                  "id=%s object_path=%s uid=" UID_FMT " runtime_path=%s "
                   "session_fd=%d seat=%s vtnr=%u",
                   s->id,
                   p,
-                  (uint32_t) s->user->user_record->uid,
+                  s->user->user_record->uid,
                   s->user->runtime_path,
                   fifo_fd,
                   s->seat ? s->seat->id : "",
-                  (uint32_t) s->vtnr);
+                  s->vtnr);
 
         return sd_bus_reply_method_return(
                         c, "soshusub",
@@ -968,7 +946,7 @@ int session_send_create_reply(Session *s, sd_bus_error *error) {
                         false);
 }
 
-int session_send_upgrade_reply(Session *s, sd_bus_error *error) {
+int session_send_upgrade_reply(Session *s, const sd_bus_error *error) {
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *c = NULL;
         assert(s);
 

src/login/logind-session-dbus.h

@@ -15,8 +15,8 @@ int session_send_changed(Session *s, const char *properties, ...) _sentinel_;
 int session_send_lock(Session *s, bool lock);
 int session_send_lock_all(Manager *m, bool lock);
 
-int session_send_create_reply(Session *s, sd_bus_error *error);
+int session_send_create_reply_bus(Session *s, const sd_bus_error *error);
-int session_send_upgrade_reply(Session *s, sd_bus_error *error);
+int session_send_upgrade_reply(Session *s, const sd_bus_error *error);
 
 int bus_session_method_activate(sd_bus_message *message, void *userdata, sd_bus_error *error);
 int bus_session_method_lock(sd_bus_message *message, void *userdata, sd_bus_error *error);

src/login/logind-session.c

@@ -29,6 +29,7 @@
 #include "logind-session-dbus.h"
 #include "logind-session.h"
 #include "logind-user-dbus.h"
+#include "logind-varlink.h"
 #include "mkdir-label.h"
 #include "parse-util.h"
 #include "path-util.h"
@@ -192,6 +193,8 @@ Session* session_free(Session *s) {
         sd_bus_message_unref(s->create_message);
         sd_bus_message_unref(s->upgrade_message);
 
+        sd_varlink_unref(s->create_link);
+
         free(s->tty);
         free(s->display);
         free(s->remote_host);
@@ -1648,6 +1651,35 @@ void session_drop_controller(Session *s) {
         session_restore_vt(s);
 }
 
+bool session_job_pending(Session *s) {
+        assert(s);
+        assert(s->user);
+
+        /* Check if we have some jobs enqueued and not finished yet. Each time we get JobRemoved signal about
+         * relevant units, session_send_create_reply and hence us is called (see match_job_removed).
+         * Note that we don't care about job result here. */
+
+        return s->scope_job ||
+               s->user->runtime_dir_job ||
+               (SESSION_CLASS_WANTS_SERVICE_MANAGER(s->class) && s->user->service_manager_job);
+}
+
+int session_send_create_reply(Session *s, const sd_bus_error *error) {
+        int r;
+
+        assert(s);
+
+        /* If error occurred, return it immediately. Otherwise let's wait for all jobs to finish before
+         * continuing. */
+        if (!sd_bus_error_is_set(error) && session_job_pending(s))
+                return 0;
+
+        r = 0;
+        RET_GATHER(r, session_send_create_reply_bus(s, error));
+        RET_GATHER(r, session_send_create_reply_varlink(s, error));
+        return r;
+}
+
 static const char* const session_state_table[_SESSION_STATE_MAX] = {
         [SESSION_OPENING] = "opening",
         [SESSION_ONLINE]  = "online",

src/login/logind-session.h

@@ -150,6 +150,8 @@ struct Session {
         sd_bus_message *create_message;   /* The D-Bus message used to create the session, which we haven't responded to yet */
         sd_bus_message *upgrade_message;  /* The D-Bus message used to upgrade the session class user-incomplete → user, which we haven't responded to yet */
 
+        sd_varlink *create_link; /* The Varlink connection used to create session, which we haven't responded to yet */
+
         /* Set up when a client requested to release the session via the bus */
         sd_event_source *timer_event_source;
 
@@ -216,6 +218,10 @@ bool session_is_controller(Session *s, const char *sender);
 int session_set_controller(Session *s, const char *sender, bool force, bool prepare);
 void session_drop_controller(Session *s);
 
+bool session_job_pending(Session *s);
+
+int session_send_create_reply(Session *s, const sd_bus_error *error);
+
 static inline bool SESSION_IS_SELF(const char *name) {
         return isempty(name) || streq(name, "self");
 }

src/login/logind-varlink.c

@@ -0,0 +1,383 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "cgroup-util.h"
+#include "fd-util.h"
+#include "json-util.h"
+#include "logind.h"
+#include "logind-dbus.h"
+#include "logind-session-dbus.h"
+#include "logind-varlink.h"
+#include "terminal-util.h"
+#include "user-util.h"
+#include "varlink-io.systemd.Login.h"
+#include "varlink-util.h"
+
+static int manager_varlink_get_session_by_peer(
+                Manager *m,
+                sd_varlink *link,
+                bool consult_display,
+                Session **ret) {
+
+        int r;
+
+        assert(m);
+        assert(link);
+        assert(ret);
+
+        /* Determines the session of the peer. If the peer is not part of a session, but consult_display is
+         * true, then will return the display session of the peer's owning user */
+
+        _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
+        r = varlink_get_peer_pidref(link, &pidref);
+        if (r < 0)
+                return log_error_errno(r, "Failed to acquire peer PID: %m");
+
+        Session *session = NULL;
+        _cleanup_free_ char *name = NULL;
+        r = cg_pidref_get_session(&pidref, &name);
+        if (r < 0) {
+                if (!consult_display)
+                        log_debug_errno(r, "Failed to acquire session of peer, giving up: %m");
+                else {
+                        log_debug_errno(r, "Failed to acquire session of peer, trying to find owner UID: %m");
+
+                        uid_t uid;
+                        r = cg_pidref_get_owner_uid(&pidref, &uid);
+                        if (r < 0)
+                                log_debug_errno(r, "Failed to acquire owning UID of peer, giving up: %m");
+                        else {
+                                User *user = hashmap_get(m->users, UID_TO_PTR(uid));
+                                if (user)
+                                        session = user->display;
+                         }
+                }
+        } else
+                session = hashmap_get(m->sessions, name);
+
+        if (!session)
+                return sd_varlink_error(link, "io.systemd.Login.NoSuchSession", /* parameters= */ NULL);
+
+        *ret = session;
+        return 0;
+}
+
+static int manager_varlink_get_session_by_name(
+                Manager *m,
+                sd_varlink *link,
+                const char *name,
+                Session **ret) {
+
+        assert(m);
+        assert(link);
+        assert(ret);
+
+        /* Resolves a session name to a session object. Supports resolving the special names "self" and "auto". */
+
+        if (SESSION_IS_SELF(name))
+                return manager_varlink_get_session_by_peer(m, link, /* consult_display= */ false, ret);
+        if (SESSION_IS_AUTO(name))
+                return manager_varlink_get_session_by_peer(m, link, /* consult_display= */ true, ret);
+
+        Session *session = hashmap_get(m->sessions, name);
+        if (!session)
+                return sd_varlink_error(link, "io.systemd.Login.NoSuchSession", /* parameters= */ NULL);
+
+        *ret = session;
+        return 0;
+}
+
+int session_send_create_reply_varlink(Session *s, const sd_bus_error *error) {
+        assert(s);
+
+        /* This is called after the session scope and the user service were successfully created, and
+         * finishes where manager_create_session() left off. */
+
+        _cleanup_(sd_varlink_unrefp) sd_varlink *vl = TAKE_PTR(s->create_link);
+        if (!vl)
+                return 0;
+
+        if (sd_bus_error_is_set(error))
+                return sd_varlink_error(vl, "io.systemd.Login.UnitAllocationFailed", /* parameters= */ NULL);
+
+        _cleanup_close_ int fifo_fd = session_create_fifo(s);
+        if (fifo_fd < 0)
+                return fifo_fd;
+
+        /* Update the session state file before we notify the client about the result. */
+        session_save(s);
+
+        log_debug("Sending Varlink reply about created session: "
+                  "id=%s uid=" UID_FMT " runtime_path=%s "
+                  "session_fd=%d seat=%s vtnr=%u",
+                  s->id,
+                  s->user->user_record->uid,
+                  s->user->runtime_path,
+                  fifo_fd,
+                  s->seat ? s->seat->id : "",
+                  s->vtnr);
+
+        int fifo_fd_idx = sd_varlink_push_fd(vl, fifo_fd);
+        if (fifo_fd_idx < 0) {
+                log_error_errno(fifo_fd_idx, "Failed to push FIFO fd to Varlink: %m");
+                return sd_varlink_error_errno(vl, fifo_fd_idx);
+        }
+
+        TAKE_FD(fifo_fd);
+
+        return sd_varlink_replybo(
+                        vl,
+                        SD_JSON_BUILD_PAIR_STRING("Id", s->id),
+                        SD_JSON_BUILD_PAIR_STRING("RuntimePath", s->user->runtime_path),
+                        SD_JSON_BUILD_PAIR_UNSIGNED("SessionFileDescriptor", fifo_fd_idx),
+                        SD_JSON_BUILD_PAIR_UNSIGNED("UID", s->user->user_record->uid),
+                        SD_JSON_BUILD_PAIR_CONDITION(!!s->seat, "Seat", SD_JSON_BUILD_STRING(s->seat ? s->seat->id : NULL)),
+                        SD_JSON_BUILD_PAIR_CONDITION(s->vtnr > 0, "VTNr", SD_JSON_BUILD_UNSIGNED(s->vtnr)));
+}
+
+static JSON_DISPATCH_ENUM_DEFINE(json_dispatch_session_class, SessionClass, session_class_from_string);
+static JSON_DISPATCH_ENUM_DEFINE(json_dispatch_session_type, SessionType, session_type_from_string);
+
+typedef struct CreateSessionParameters {
+        uid_t uid;
+        PidRef pid;
+        const char *service;
+        SessionType type;
+        SessionClass class;
+        const char *desktop;
+        const char *seat;
+        unsigned vtnr;
+        const char *tty;
+        const char *display;
+        int remote;
+        const char *remote_user;
+        const char *remote_host;
+} CreateSessionParameters;
+
+static void create_session_parameters_done(CreateSessionParameters *p) {
+        pidref_done(&p->pid);
+}
+
+static int vl_method_create_session(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
+        Manager *m = ASSERT_PTR(userdata);
+        int r;
+
+        static const sd_json_dispatch_field dispatch_table[] = {
+                { "UID",        _SD_JSON_VARIANT_TYPE_INVALID, sd_json_dispatch_uid_gid,      offsetof(CreateSessionParameters, uid),         SD_JSON_MANDATORY },
+                { "PID",        _SD_JSON_VARIANT_TYPE_INVALID, json_dispatch_pidref,          offsetof(CreateSessionParameters, pid),         0                 },
+                { "Service",    SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, offsetof(CreateSessionParameters, service),     0                 },
+                { "Type",       SD_JSON_VARIANT_STRING,        json_dispatch_session_type,    offsetof(CreateSessionParameters, type),        SD_JSON_MANDATORY },
+                { "Class",      SD_JSON_VARIANT_STRING,        json_dispatch_session_class,   offsetof(CreateSessionParameters, class),       SD_JSON_MANDATORY },
+                { "Desktop",    SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, offsetof(CreateSessionParameters, desktop),     SD_JSON_STRICT    },
+                { "Seat",       SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, offsetof(CreateSessionParameters, seat),        0                 },
+                { "VTNr",       _SD_JSON_VARIANT_TYPE_INVALID, sd_json_dispatch_uint,         offsetof(CreateSessionParameters, vtnr),        0                 },
+                { "TTY",        SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, offsetof(CreateSessionParameters, tty),         0                 },
+                { "Display",    SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, offsetof(CreateSessionParameters, display),     0                 },
+                { "Remote",     SD_JSON_VARIANT_BOOLEAN,       sd_json_dispatch_tristate,     offsetof(CreateSessionParameters, remote),      0                 },
+                { "RemoteUser", SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, offsetof(CreateSessionParameters, remote_user), 0                 },
+                { "RemoteHost", SD_JSON_VARIANT_STRING,        sd_json_dispatch_const_string, offsetof(CreateSessionParameters, remote_host), 0                 },
+                {}
+        };
+
+        _cleanup_(create_session_parameters_done) CreateSessionParameters p = {
+                .uid = UID_INVALID,
+                .pid = PIDREF_NULL,
+                .class = _SESSION_CLASS_INVALID,
+                .type = _SESSION_TYPE_INVALID,
+                .remote = -1,
+        };
+
+        r = sd_varlink_dispatch(link, parameters, dispatch_table, &p);
+        if (r != 0)
+                return r;
+
+        Seat *seat = NULL;
+        if (p.seat) {
+                seat = hashmap_get(m->seats, p.seat);
+                if (!seat)
+                        return sd_varlink_replyb(link, "io.systemd.Login.NoSuchSeat", /* parameters= */ NULL);
+        }
+
+        if (p.tty) {
+                if (tty_is_vc(p.tty)) {
+                        if (!seat)
+                                seat = m->seat0;
+                        else if (seat != m->seat0)
+                                return sd_varlink_error_invalid_parameter_name(link, "Seat");
+
+                        int v = vtnr_from_tty(p.tty);
+                        if (v <= 0)
+                                return sd_varlink_error_invalid_parameter_name(link, "TTY");
+
+                        if (p.vtnr == 0)
+                                p.vtnr = v;
+                        else if (p.vtnr != (unsigned) v)
+                                return sd_varlink_error_invalid_parameter_name(link, "VTNr");
+
+                } else if (tty_is_console(p.tty)) {
+                        if (!seat)
+                                seat = m->seat0;
+                        else if (seat != m->seat0)
+                                return sd_varlink_error_invalid_parameter_name(link, "Seat");
+
+                        if (p.vtnr != 0)
+                                return sd_varlink_error_invalid_parameter_name(link, "VTNr");
+                }
+        }
+
+        if (seat) {
+                if (seat_has_vts(seat)) {
+                        if (!vtnr_is_valid(p.vtnr))
+                                return sd_varlink_error_invalid_parameter_name(link, "VTNr");
+                } else {
+                        if (p.vtnr != 0)
+                                return sd_varlink_error_invalid_parameter_name(link, "VTNr");
+                }
+        }
+
+        if (p.remote < 0)
+                p.remote = p.remote_user || p.remote_host;
+
+        /* Before we continue processing this, let's ensure the peer is privileged */
+        uid_t peer_uid;
+        r = sd_varlink_get_peer_uid(link, &peer_uid);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to get peer UID: %m");
+        if (peer_uid != 0)
+                return sd_varlink_error(link, SD_VARLINK_ERROR_PERMISSION_DENIED, /* parameters= */ NULL);
+
+        if (!pidref_is_set(&p.pid)) {
+                r = varlink_get_peer_pidref(link, &p.pid);
+                if (r < 0)
+                        return log_debug_errno(r, "Failed to get peer pidref: %m");
+        }
+
+        Session *session;
+        r = manager_create_session(
+                        m,
+                        p.uid,
+                        &p.pid,
+                        p.service,
+                        p.type,
+                        p.class,
+                        p.desktop,
+                        seat,
+                        p.vtnr,
+                        p.tty,
+                        p.display,
+                        p.remote,
+                        p.remote_user,
+                        p.remote_host,
+                        &session);
+        if (r == -EBUSY)
+                return sd_varlink_error(link, "io.systemd.Login.AlreadySessionMember", /* parameters= */ NULL);
+        if (r == -EADDRNOTAVAIL)
+                return sd_varlink_error(link, "io.systemd.Login.VirtualTerminalAlreadyTaken", /* parameters= */ NULL);
+        if (r == -EUSERS)
+                return sd_varlink_error(link, "io.systemd.Login.TooManySessions", /* parameters= */ NULL);
+        if (r < 0)
+                return r;
+
+        r = session_start(session, /* properties= */ NULL, /* error= */ NULL);
+        if (r < 0)
+                goto fail;
+
+        session->create_link = sd_varlink_ref(link);
+
+        /* Let's check if this is complete now */
+        r = session_send_create_reply(session, /* error= */ NULL);
+        if (r < 0)
+                goto fail;
+
+        return 1;
+
+fail:
+        if (session)
+                session_add_to_gc_queue(session);
+
+        return r;
+}
+
+static int vl_method_release_session(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
+        Manager *m = ASSERT_PTR(userdata);
+        int r;
+
+        struct {
+                const char *id;
+        } p;
+
+        static const sd_json_dispatch_field dispatch_table[] = {
+                { "Id", SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, voffsetof(p, id), SD_JSON_MANDATORY },
+                {}
+        };
+
+        r = sd_varlink_dispatch(link, parameters, dispatch_table, &p);
+        if (r != 0)
+                return r;
+
+        Session *session;
+        r = manager_varlink_get_session_by_name(m, link, p.id, &session);
+        if (r != 0)
+                return r;
+
+        Session *peer_session;
+        r = manager_varlink_get_session_by_peer(m, link, /* consult_display= */ false, &peer_session);
+        if (r != 0)
+                return r;
+
+        if (session != peer_session)
+                return sd_varlink_error(link, SD_VARLINK_ERROR_PERMISSION_DENIED, /* parameters= */ NULL);
+
+        r = session_release(session);
+        if (r < 0)
+                return r;
+
+        return sd_varlink_replyb(link, SD_JSON_BUILD_EMPTY_OBJECT);
+}
+
+int manager_varlink_init(Manager *m) {
+        _cleanup_(sd_varlink_server_unrefp) sd_varlink_server *s = NULL;
+        int r;
+
+        assert(m);
+
+        if (m->varlink_server)
+                return 0;
+
+        r = sd_varlink_server_new(
+                        &s,
+                        SD_VARLINK_SERVER_ACCOUNT_UID|
+                        SD_VARLINK_SERVER_INHERIT_USERDATA|
+                        SD_VARLINK_SERVER_ALLOW_FD_PASSING_OUTPUT);
+        if (r < 0)
+                return log_error_errno(r, "Failed to allocate varlink server object: %m");
+
+        sd_varlink_server_set_userdata(s, m);
+
+        r = sd_varlink_server_add_interface(s, &vl_interface_io_systemd_Login);
+        if (r < 0)
+                return log_error_errno(r, "Failed to add Login interface to varlink server: %m");
+
+        r = sd_varlink_server_bind_method_many(
+                        s,
+                        "io.systemd.Login.CreateSession",  vl_method_create_session,
+                        "io.systemd.Login.ReleaseSession", vl_method_release_session);
+        if (r < 0)
+                return log_error_errno(r, "Failed to register varlink methods: %m");
+
+        r = sd_varlink_server_listen_address(s, "/run/systemd/io.systemd.Login", 0666);
+        if (r < 0)
+                return log_error_errno(r, "Failed to bind to varlink socket: %m");
+
+        r = sd_varlink_server_attach_event(s, m->event, SD_EVENT_PRIORITY_NORMAL);
+        if (r < 0)
+                return log_error_errno(r, "Failed to attach varlink connection to event loop: %m");
+
+        m->varlink_server = TAKE_PTR(s);
+        return 0;
+}
+
+void manager_varlink_done(Manager *m) {
+        assert(m);
+
+        m->varlink_server = sd_varlink_server_unref(m->varlink_server);
+}

src/login/logind-varlink.h

@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-bus.h"
+
+#include "logind.h"
+#include "logind-session.h"
+
+int manager_varlink_init(Manager *m);
+void manager_varlink_done(Manager *m);
+
+int session_send_create_reply_varlink(Session *s, const sd_bus_error *error);

src/login/logind.c

@@ -24,11 +24,12 @@
 #include "fd-util.h"
 #include "format-util.h"
 #include "fs-util.h"
+#include "logind.h"
 #include "logind-dbus.h"
 #include "logind-seat-dbus.h"
 #include "logind-session-dbus.h"
 #include "logind-user-dbus.h"
-#include "logind.h"
+#include "logind-varlink.h"
 #include "main-func.h"
 #include "mkdir-label.h"
 #include "parse-util.h"
@@ -153,6 +154,8 @@ static Manager* manager_free(Manager *m) {
 
         hashmap_free(m->polkit_registry);
 
+        manager_varlink_done(m);
+
         sd_bus_flush_close_unref(m->bus);
         sd_event_unref(m->event);
 
@@ -1114,6 +1117,10 @@ static int manager_startup(Manager *m) {
         if (r < 0)
                 return r;
 
+        r = manager_varlink_init(m);
+        if (r < 0)
+                return r;
+
         /* Instantiate magic seat 0 */
         r = manager_add_seat(m, "seat0", &m->seat0);
         if (r < 0)

src/login/logind.h

@@ -7,6 +7,7 @@
 #include "sd-bus.h"
 #include "sd-device.h"
 #include "sd-event.h"
+#include "sd-varlink.h"
 
 #include "calendarspec.h"
 #include "conf-parser.h"
@@ -145,6 +146,8 @@ struct Manager {
         struct stat efi_loader_entry_one_shot_stat;
 
         CalendarSpec *maintenance_time;
+
+        sd_varlink_server *varlink_server;
 };
 
 void manager_reset_config(Manager *m);

src/login/meson.build

@@ -26,6 +26,7 @@ liblogind_core_sources = files(
         'logind-session.c',
         'logind-user-dbus.c',
         'logind-user.c',
+        'logind-varlink.c',
         'logind-wall.c',
 )
 

src/shared/meson.build

@@ -182,6 +182,7 @@ shared_sources = files(
         'varlink-io.systemd.Hostname.c',
         'varlink-io.systemd.Import.c',
         'varlink-io.systemd.Journal.c',
+        'varlink-io.systemd.Login.c',
         'varlink-io.systemd.Machine.c',
         'varlink-io.systemd.MachineImage.c',
         'varlink-io.systemd.ManagedOOM.c',

src/shared/pam-util.c

@@ -253,17 +253,17 @@ int pam_get_item_many_internal(pam_handle_t *handle, ...) {
         va_list ap;
         int r;
 
+        assert(handle);
+
         va_start(ap, handle);
         for (;;) {
                 int item_type = va_arg(ap, int);
-
                 if (item_type <= 0) {
                         r = PAM_SUCCESS;
                         break;
                 }
 
                 const void **value = ASSERT_PTR(va_arg(ap, const void **));
-
                 r = pam_get_item(handle, item_type, value);
                 if (!IN_SET(r, PAM_BAD_ITEM, PAM_SUCCESS))
                         break;
@@ -273,6 +273,30 @@ int pam_get_item_many_internal(pam_handle_t *handle, ...) {
         return r;
 }
 
+int pam_get_data_many_internal(pam_handle_t *handle, ...) {
+        va_list ap;
+        int r;
+
+        assert(handle);
+
+        va_start(ap, handle);
+        for (;;) {
+                const char *data_name = va_arg(ap, const char *);
+                if (!data_name) {
+                        r = PAM_SUCCESS;
+                        break;
+                }
+
+                const void **value = ASSERT_PTR(va_arg(ap, const void **));
+                r = pam_get_data(handle, data_name, value);
+                if (!IN_SET(r, PAM_NO_MODULE_DATA, PAM_SUCCESS))
+                        break;
+        }
+        va_end(ap);
+
+        return r;
+}
+
 int pam_prompt_graceful(pam_handle_t *handle, int style, char **ret_response, const char *fmt, ...) {
         va_list args;
         int r;

src/shared/pam-util.h

@@ -44,7 +44,9 @@ int pam_get_bus_data(pam_handle_t *handle, const char *module_name, PamBusData *
 void pam_cleanup_free(pam_handle_t *handle, void *data, int error_status);
 
 int pam_get_item_many_internal(pam_handle_t *handle, ...);
-
 #define pam_get_item_many(handle, ...) pam_get_item_many_internal(handle, __VA_ARGS__, -1)
 
+int pam_get_data_many_internal(pam_handle_t *handle, ...);
+#define pam_get_data_many(handle, ...) pam_get_data_many_internal(handle, __VA_ARGS__, NULL)
+
 int pam_prompt_graceful(pam_handle_t *handle, int style, char **ret_response, const char *fmt, ...) _printf_(4,5);

src/shared/tpm2-util.h

@@ -392,7 +392,7 @@ int tpm2_make_pcr_json_array(uint32_t pcr_mask, sd_json_variant **ret);
 int tpm2_parse_pcr_json_array(sd_json_variant *v, uint32_t *ret);
 
 int tpm2_make_luks2_json(int keyslot, uint32_t hash_pcr_mask, uint16_t pcr_bank, const struct iovec *pubkey, uint32_t pubkey_pcr_mask, uint16_t primary_alg, const struct iovec blobs[], size_t n_blobs, const struct iovec policy_hash[], size_t n_policy_hash, const struct iovec *salt, const struct iovec *srk, const struct iovec *pcrlock_nv, TPM2Flags flags, sd_json_variant **ret);
-int tpm2_parse_luks2_json(sd_json_variant *v, int *ret_keyslot, uint32_t *ret_hash_pcr_mask, uint16_t *ret_pcr_bank, struct iovec *ret_pubkey, uint32_t *ret_pubkey_pcr_mask, uint16_t *ret_primary_alg, struct iovec **ret_blobs, size_t *ret_n_blobs, struct iovec **ret_policy_hash, size_t *ret_n_policy_hash, struct iovec *ret_salt, struct iovec *ret_srk, struct iovec *pcrlock_nv, TPM2Flags *ret_flags);
+int tpm2_parse_luks2_json(sd_json_variant *v, int *ret_keyslot, uint32_t *ret_hash_pcr_mask, uint16_t *ret_pcr_bank, struct iovec *ret_pubkey, uint32_t *ret_pubkey_pcr_mask, uint16_t *ret_primary_alg, struct iovec **ret_blobs, size_t *ret_n_blobs, struct iovec **ret_policy_hash, size_t *ret_n_policy_hash, struct iovec *ret_salt, struct iovec *ret_srk, struct iovec *ret_pcrlock_nv, TPM2Flags *ret_flags);
 
 /* Default to PCR 7 only */
 #define TPM2_PCR_INDEX_DEFAULT UINT32_C(7)

src/shared/varlink-io.systemd.Login.c

@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bus-polkit.h"
+#include "varlink-idl-common.h"
+#include "varlink-io.systemd.Login.h"
+
+static SD_VARLINK_DEFINE_ENUM_TYPE(
+                SessionType,
+                SD_VARLINK_DEFINE_ENUM_VALUE(unspecified),
+                SD_VARLINK_DEFINE_ENUM_VALUE(tty),
+                SD_VARLINK_DEFINE_ENUM_VALUE(x11),
+                SD_VARLINK_DEFINE_ENUM_VALUE(wayland),
+                SD_VARLINK_DEFINE_ENUM_VALUE(mir),
+                SD_VARLINK_DEFINE_ENUM_VALUE(web));
+
+static SD_VARLINK_DEFINE_ENUM_TYPE(
+                SessionClass,
+                SD_VARLINK_FIELD_COMMENT("Regular user sessions"),
+                SD_VARLINK_DEFINE_ENUM_VALUE(user),
+                SD_VARLINK_FIELD_COMMENT("Session of the root user that shall be open for login from earliest moment on, and not be delayed for /run/nologin"),
+                SD_VARLINK_DEFINE_ENUM_VALUE(user_early),
+                SD_VARLINK_FIELD_COMMENT("Regular user session whose home directory is not available right now, but will be later, at which point the session class can be upgraded to 'user'"),
+                SD_VARLINK_DEFINE_ENUM_VALUE(user_incomplete),
+                SD_VARLINK_FIELD_COMMENT("Display manager greeter screen used for login"),
+                SD_VARLINK_DEFINE_ENUM_VALUE(greeter),
+                SD_VARLINK_FIELD_COMMENT("Similar, but a a lock screen"),
+                SD_VARLINK_DEFINE_ENUM_VALUE(lock_screen),
+                SD_VARLINK_FIELD_COMMENT("Background session (that has no TTY, VT, Seat)"),
+                SD_VARLINK_DEFINE_ENUM_VALUE(background),
+                SD_VARLINK_FIELD_COMMENT("Similar, but for which no service manager is invoked"),
+                SD_VARLINK_DEFINE_ENUM_VALUE(background_light),
+                SD_VARLINK_FIELD_COMMENT("The special session of the service manager"),
+                SD_VARLINK_DEFINE_ENUM_VALUE(manager),
+                SD_VARLINK_FIELD_COMMENT("The special session of the service manager for the root user"),
+                SD_VARLINK_DEFINE_ENUM_VALUE(manager_early));
+
+static SD_VARLINK_DEFINE_METHOD(
+                CreateSession,
+                SD_VARLINK_FIELD_COMMENT("Numeric UNIX UID of the user this session shall be owned by"),
+                SD_VARLINK_DEFINE_INPUT(UID, SD_VARLINK_INT, 0),
+                SD_VARLINK_FIELD_COMMENT("Process that shall become the leader of the session. If null defaults to the IPC client."),
+                SD_VARLINK_DEFINE_INPUT_BY_TYPE(PID, ProcessId, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("PAM service name of the program requesting the session"),
+                SD_VARLINK_DEFINE_INPUT(Service, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("The type of the session"),
+                SD_VARLINK_DEFINE_INPUT_BY_TYPE(Type, SessionType, 0),
+                SD_VARLINK_FIELD_COMMENT("The class of the session"),
+                SD_VARLINK_DEFINE_INPUT_BY_TYPE(Class, SessionClass, 0),
+                SD_VARLINK_FIELD_COMMENT("An identifier for the chosen desktop"),
+                SD_VARLINK_DEFINE_INPUT(Desktop, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("The name of the seat to assign this session to"),
+                SD_VARLINK_DEFINE_INPUT(Seat, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("The virtual terminal number to assign this session to"),
+                SD_VARLINK_DEFINE_INPUT(VTNr, SD_VARLINK_INT, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("The TTY device to assign this session to, if applicable"),
+                SD_VARLINK_DEFINE_INPUT(TTY, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("The X11 display for this session"),
+                SD_VARLINK_DEFINE_INPUT(Display, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("If true this is a remote session"),
+                SD_VARLINK_DEFINE_INPUT(Remote, SD_VARLINK_BOOL, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("User name on the remote site, if known"),
+                SD_VARLINK_DEFINE_INPUT(RemoteUser, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("Host name of the remote host"),
+                SD_VARLINK_DEFINE_INPUT(RemoteHost, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("The identifier string of the session of the user."),
+                SD_VARLINK_DEFINE_OUTPUT(Id, SD_VARLINK_STRING, 0),
+                SD_VARLINK_FIELD_COMMENT("The runtime path ($XDG_RUNTIME_DIR) of the user."),
+                SD_VARLINK_DEFINE_OUTPUT(RuntimePath, SD_VARLINK_STRING, 0),
+                SD_VARLINK_FIELD_COMMENT("Index into the file descriptor table of this reply with the session tracking fd for this session."),
+                SD_VARLINK_DEFINE_OUTPUT(SessionFileDescriptor, SD_VARLINK_INT, 0),
+                SD_VARLINK_FIELD_COMMENT("The original UID of this session."),
+                SD_VARLINK_DEFINE_OUTPUT(UID, SD_VARLINK_INT, 0),
+                SD_VARLINK_FIELD_COMMENT("The seat this session has been assigned to"),
+                SD_VARLINK_DEFINE_OUTPUT(Seat, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("The virtual terminal number the session has been assigned to"),
+                SD_VARLINK_DEFINE_OUTPUT(VTNr, SD_VARLINK_INT, SD_VARLINK_NULLABLE));
+
+static SD_VARLINK_DEFINE_METHOD(
+                ReleaseSession,
+                SD_VARLINK_FIELD_COMMENT("The identifier string of the session to release. If unspecified or 'self', will return the callers session."),
+                SD_VARLINK_DEFINE_INPUT(Id, SD_VARLINK_STRING, SD_VARLINK_NULLABLE));
+
+static SD_VARLINK_DEFINE_ERROR(NoSuchSession);
+static SD_VARLINK_DEFINE_ERROR(NoSuchSeat);
+static SD_VARLINK_DEFINE_ERROR(AlreadySessionMember);
+static SD_VARLINK_DEFINE_ERROR(VirtualTerminalAlreadyTaken);
+static SD_VARLINK_DEFINE_ERROR(TooManySessions);
+static SD_VARLINK_DEFINE_ERROR(UnitAllocationFailed);
+
+SD_VARLINK_DEFINE_INTERFACE(
+                io_systemd_Login,
+                "io.systemd.Login",
+                SD_VARLINK_INTERFACE_COMMENT("APIs for managing login sessions."),
+                SD_VARLINK_SYMBOL_COMMENT("Process identifier"),
+                &vl_type_ProcessId,
+                SD_VARLINK_SYMBOL_COMMENT("Various types of sessions"),
+                &vl_type_SessionType,
+                SD_VARLINK_SYMBOL_COMMENT("Various classes of sessions"),
+                &vl_type_SessionClass,
+                SD_VARLINK_SYMBOL_COMMENT("Allocates a new session."),
+                &vl_method_CreateSession,
+                SD_VARLINK_SYMBOL_COMMENT("Releases an existing session. Currently, will be refuses unless originating from the session to release itself."),
+                &vl_method_ReleaseSession,
+                SD_VARLINK_SYMBOL_COMMENT("No session by this name found"),
+                &vl_error_NoSuchSession,
+                SD_VARLINK_SYMBOL_COMMENT("No seat by this name found"),
+                &vl_error_NoSuchSeat,
+                SD_VARLINK_SYMBOL_COMMENT("Process already member of a session"),
+                &vl_error_AlreadySessionMember,
+                SD_VARLINK_SYMBOL_COMMENT("The specified virtual terminal (VT) is already taken by another session"),
+                &vl_error_VirtualTerminalAlreadyTaken,
+                SD_VARLINK_SYMBOL_COMMENT("Maximum number of sessions reached"),
+                &vl_error_TooManySessions,
+                SD_VARLINK_SYMBOL_COMMENT("Failed to allocate a unit for the session"),
+                &vl_error_UnitAllocationFailed);

src/shared/varlink-io.systemd.Login.h

@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-varlink-idl.h"
+
+extern const sd_varlink_interface vl_interface_io_systemd_Login;

src/systemd/sd-varlink.h

@@ -65,11 +65,13 @@ __extension__ typedef enum _SD_ENUM_TYPE_S64(sd_varlink_method_flags_t) {
 } sd_varlink_method_flags_t;
 
 __extension__ typedef enum _SD_ENUM_TYPE_S64(sd_varlink_server_flags_t) {
-        SD_VARLINK_SERVER_ROOT_ONLY        = 1 << 0, /* Only accessible by root */
+        SD_VARLINK_SERVER_ROOT_ONLY               = 1 << 0, /* Only accessible by root */
-        SD_VARLINK_SERVER_MYSELF_ONLY      = 1 << 1, /* Only accessible by our own UID */
+        SD_VARLINK_SERVER_MYSELF_ONLY             = 1 << 1, /* Only accessible by our own UID */
-        SD_VARLINK_SERVER_ACCOUNT_UID      = 1 << 2, /* Do per user accounting */
+        SD_VARLINK_SERVER_ACCOUNT_UID             = 1 << 2, /* Do per user accounting */
-        SD_VARLINK_SERVER_INHERIT_USERDATA = 1 << 3, /* Initialize Varlink connection userdata from sd_varlink_server userdata */
+        SD_VARLINK_SERVER_INHERIT_USERDATA        = 1 << 3, /* Initialize Varlink connection userdata from sd_varlink_server userdata */
-        SD_VARLINK_SERVER_INPUT_SENSITIVE  = 1 << 4, /* Automatically mark all connection input as sensitive */
+        SD_VARLINK_SERVER_INPUT_SENSITIVE         = 1 << 4, /* Automatically mark all connection input as sensitive */
+        SD_VARLINK_SERVER_ALLOW_FD_PASSING_INPUT  = 1 << 5, /* Allow receiving fds over all connections */
+        SD_VARLINK_SERVER_ALLOW_FD_PASSING_OUTPUT = 1 << 6, /* Allow sending fds over all connections */
         _SD_ENUM_FORCE_S64(SD_VARLINK_SERVER)
 } sd_varlink_server_flags_t;
 

src/test/test-cgroup-util.c

@@ -212,8 +212,8 @@ TEST(proc) {
 
                 cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid.pid, &path);
                 cg_pid_get_path_shifted(pid.pid, NULL, &path_shifted);
-                cg_pid_get_owner_uid(pid.pid, &uid);
+                cg_pidref_get_owner_uid(&pid, &uid);
-                cg_pid_get_session(pid.pid, &session);
+                cg_pidref_get_session(&pid, &session);
                 cg_pid_get_unit(pid.pid, &unit);
                 cg_pid_get_user_unit(pid.pid, &user_unit);
                 cg_pid_get_machine_name(pid.pid, &machine);

src/test/test-varlink-idl.c

@@ -14,6 +14,7 @@
 #include "varlink-io.systemd.Credentials.h"
 #include "varlink-io.systemd.Import.h"
 #include "varlink-io.systemd.Journal.h"
+#include "varlink-io.systemd.Login.h"
 #include "varlink-io.systemd.Machine.h"
 #include "varlink-io.systemd.MachineImage.h"
 #include "varlink-io.systemd.ManagedOOM.h"
@@ -193,6 +194,8 @@ TEST(parse_format) {
         print_separator();
         test_parse_format_one(&vl_interface_io_systemd_MachineImage);
         print_separator();
+        test_parse_format_one(&vl_interface_io_systemd_Login);
+        print_separator();
         test_parse_format_one(&vl_interface_xyz_test);
 }
 

src/userdb/userdbctl.c

@@ -23,6 +23,7 @@
 #include "user-util.h"
 #include "userdb.h"
 #include "verbs.h"
+#include "virt.h"
 
 static enum {
         OUTPUT_CLASSIC,
@@ -139,10 +140,16 @@ static int show_user(UserRecord *ur, Table *table) {
         return 0;
 }
 
+static bool test_show_mapped(void) {
+        /* Show mapped user range only in environments where user mapping is a thing. */
+        return running_in_userns() > 0;
+}
+
 static const struct {
         uid_t first, last;
         const char *name;
         UserDisposition disposition;
+        bool (*test)(void);
 } uid_range_table[] = {
         {
                 .first = 1,
@@ -175,11 +182,12 @@ static const struct {
                 .last = MAP_UID_MAX,
                 .name = "mapped",
                 .disposition = USER_REGULAR,
+                .test = test_show_mapped,
         },
 };
 
 static int table_add_uid_boundaries(Table *table, const UIDRange *p) {
-        int r;
+        int r, n_added = 0;
 
         assert(table);
 
@@ -192,6 +200,9 @@ static int table_add_uid_boundaries(Table *table, const UIDRange *p) {
                 if (!uid_range_covers(p, i->first, i->last - i->first + 1))
                         continue;
 
+                if (i->test && !i->test())
+                        continue;
+
                 name = strjoin(special_glyph(SPECIAL_GLYPH_ARROW_DOWN),
                                " begin ", i->name, " users ",
                                special_glyph(SPECIAL_GLYPH_ARROW_DOWN));
@@ -249,9 +260,11 @@ static int table_add_uid_boundaries(Table *table, const UIDRange *p) {
                                 TABLE_INT, 1); /* sort after any other entry with the same UID */
                 if (r < 0)
                         return table_log_add_error(r);
+
+                n_added += 2;
         }
 
-        return ELEMENTSOF(uid_range_table) * 2;
+        return n_added;
 }
 
 static int add_unavailable_uid(Table *table, uid_t start, uid_t end) {
@@ -565,16 +578,22 @@ static int show_group(GroupRecord *gr, Table *table) {
 }
 
 static int table_add_gid_boundaries(Table *table, const UIDRange *p) {
-        int r;
+        int r, n_added = 0;
 
         assert(table);
 
         FOREACH_ELEMENT(i, uid_range_table) {
                 _cleanup_free_ char *name = NULL, *comment = NULL;
 
+                if (!FLAGS_SET(arg_disposition_mask, UINT64_C(1) << i->disposition))
+                        continue;
+
                 if (!uid_range_covers(p, i->first, i->last - i->first + 1))
                         continue;
 
+                if (i->test && !i->test())
+                        continue;
+
                 name = strjoin(special_glyph(SPECIAL_GLYPH_ARROW_DOWN),
                                " begin ", i->name, " groups ",
                                special_glyph(SPECIAL_GLYPH_ARROW_DOWN));
@@ -626,9 +645,11 @@ static int table_add_gid_boundaries(Table *table, const UIDRange *p) {
                                 TABLE_INT, 1); /* sort after any other entry with the same GID */
                 if (r < 0)
                         return table_log_add_error(r);
+
+                n_added += 2;
         }
 
-        return ELEMENTSOF(uid_range_table) * 2;
+        return n_added;
 }
 
 static int add_unavailable_gid(Table *table, uid_t start, uid_t end) {

test/units/TEST-35-LOGIN.sh

@@ -739,6 +739,10 @@ EOF
     systemctl stop user@"$uid".service
 }
 
+testcase_varlink() {
+    varlinkctl introspect /run/systemd/io.systemd.Login
+}
+
 setup_test_user
 test_write_dropin
 run_testcases

tmpfiles.d/legacy.conf.in

@@ -13,11 +13,12 @@
 
 d /run/lock 0755 root root -
 L /var/lock - - - - ../run/lock
+
+{% if HAVE_SYSV_COMPAT %}
 {% if CREATE_LOG_DIRS %}
 L$ /var/log/README - - - - ../..{{DOC_DIR}}/README.logs
 {% endif %}
 
-{% if HAVE_SYSV_COMPAT %}
 # /run/lock/subsys is used for serializing SysV service execution, and
 # hence without use on SysV-less systems.
 d /run/lock/subsys 0755 root root -