Adding upstream version 247.3.upstream/247.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

6 files changed, 1970 insertions, 0 deletions

diff --git a/src/userdb/meson.build b/src/userdb/meson.build
new file mode 100644
index 0000000..3a6225e
--- /dev/null
+++ b/src/userdb/meson.build
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+systemd_userwork_sources = files('''
+        userwork.c
+'''.split())
+
+systemd_userdbd_sources = files('''
+        userdbd-manager.c
+        userdbd-manager.h
+        userdbd.c
+'''.split())
+
+userdbctl_sources = files('''
+        userdbctl.c
+'''.split())
diff --git a/src/userdb/userdbctl.c b/src/userdb/userdbctl.c
new file mode 100644
index 0000000..a0e22df
--- /dev/null
+++ b/src/userdb/userdbctl.c
@@ -0,0 +1,789 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <getopt.h>
+#include <utmp.h>
+
+#include "dirent-util.h"
+#include "errno-list.h"
+#include "fd-util.h"
+#include "format-table.h"
+#include "format-util.h"
+#include "main-func.h"
+#include "pager.h"
+#include "parse-util.h"
+#include "pretty-print.h"
+#include "socket-util.h"
+#include "strv.h"
+#include "terminal-util.h"
+#include "user-record-show.h"
+#include "user-util.h"
+#include "userdb.h"
+#include "verbs.h"
+
+static enum {
+        OUTPUT_CLASSIC,
+        OUTPUT_TABLE,
+        OUTPUT_FRIENDLY,
+        OUTPUT_JSON,
+        _OUTPUT_INVALID = -1
+} arg_output = _OUTPUT_INVALID;
+
+static PagerFlags arg_pager_flags = 0;
+static bool arg_legend = true;
+static char** arg_services = NULL;
+static UserDBFlags arg_userdb_flags = 0;
+
+STATIC_DESTRUCTOR_REGISTER(arg_services, strv_freep);
+
+static int show_user(UserRecord *ur, Table *table) {
+        int r;
+
+        assert(ur);
+
+        switch (arg_output) {
+
+        case OUTPUT_CLASSIC:
+                if (!uid_is_valid(ur->uid))
+                        break;
+
+                printf("%s:x:" UID_FMT ":" GID_FMT ":%s:%s:%s\n",
+                       ur->user_name,
+                       ur->uid,
+                       user_record_gid(ur),
+                       strempty(user_record_real_name(ur)),
+                       user_record_home_directory(ur),
+                       user_record_shell(ur));
+
+                break;
+
+        case OUTPUT_JSON:
+                json_variant_dump(ur->json, JSON_FORMAT_COLOR_AUTO|JSON_FORMAT_PRETTY, NULL, 0);
+                break;
+
+        case OUTPUT_FRIENDLY:
+                user_record_show(ur, true);
+
+                if (ur->incomplete) {
+                        fflush(stdout);
+                        log_warning("Warning: lacking rights to acquire privileged fields of user record of '%s', output incomplete.", ur->user_name);
+                }
+
+                break;
+
+        case OUTPUT_TABLE:
+                assert(table);
+
+                r = table_add_many(
+                                table,
+                                TABLE_STRING, ur->user_name,
+                                TABLE_STRING, user_disposition_to_string(user_record_disposition(ur)),
+                                TABLE_UID, ur->uid,
+                                TABLE_GID, user_record_gid(ur),
+                                TABLE_STRING, empty_to_null(ur->real_name),
+                                TABLE_STRING, user_record_home_directory(ur),
+                                TABLE_STRING, user_record_shell(ur),
+                                TABLE_INT, (int) user_record_disposition(ur));
+                if (r < 0)
+                        return table_log_add_error(r);
+
+                break;
+
+        default:
+                assert_not_reached("Unexpected output mode");
+        }
+
+        return 0;
+}
+
+static int display_user(int argc, char *argv[], void *userdata) {
+        _cleanup_(table_unrefp) Table *table = NULL;
+        bool draw_separator = false;
+        int ret = 0, r;
+
+        if (arg_output < 0)
+                arg_output = argc > 1 ? OUTPUT_FRIENDLY : OUTPUT_TABLE;
+
+        if (arg_output == OUTPUT_TABLE) {
+                table = table_new("name", "disposition", "uid", "gid", "realname", "home", "shell", "disposition-numeric");
+                if (!table)
+                        return log_oom();
+
+                (void) table_set_align_percent(table, table_get_cell(table, 0, 2), 100);
+                (void) table_set_align_percent(table, table_get_cell(table, 0, 3), 100);
+                (void) table_set_empty_string(table, "-");
+                (void) table_set_sort(table, (size_t) 7, (size_t) 2, (size_t) -1);
+                (void) table_set_display(table, (size_t) 0, (size_t) 1, (size_t) 2, (size_t) 3, (size_t) 4, (size_t) 5, (size_t) 6, (size_t) -1);
+        }
+
+        if (argc > 1) {
+                char **i;
+
+                STRV_FOREACH(i, argv + 1) {
+                        _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
+                        uid_t uid;
+
+                        if (parse_uid(*i, &uid) >= 0)
+                                r = userdb_by_uid(uid, arg_userdb_flags, &ur);
+                        else
+                                r = userdb_by_name(*i, arg_userdb_flags, &ur);
+                        if (r < 0) {
+                                if (r == -ESRCH)
+                                        log_error_errno(r, "User %s does not exist.", *i);
+                                else if (r == -EHOSTDOWN)
+                                        log_error_errno(r, "Selected user database service is not available for this request.");
+                                else
+                                        log_error_errno(r, "Failed to find user %s: %m", *i);
+
+                                if (ret >= 0)
+                                        ret = r;
+                        } else {
+                                if (draw_separator && arg_output == OUTPUT_FRIENDLY)
+                                        putchar('\n');
+
+                                r = show_user(ur, table);
+                                if (r < 0)
+                                        return r;
+
+                                draw_separator = true;
+                        }
+                }
+        } else {
+                _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+
+                r = userdb_all(arg_userdb_flags, &iterator);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to enumerate users: %m");
+
+                for (;;) {
+                        _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
+
+                        r = userdb_iterator_get(iterator, &ur);
+                        if (r == -ESRCH)
+                                break;
+                        if (r == -EHOSTDOWN)
+                                return log_error_errno(r, "Selected user database service is not available for this request.");
+                        if (r < 0)
+                                return log_error_errno(r, "Failed acquire next user: %m");
+
+                        if (draw_separator && arg_output == OUTPUT_FRIENDLY)
+                                putchar('\n');
+
+                        r = show_user(ur, table);
+                        if (r < 0)
+                                return r;
+
+                        draw_separator = true;
+                }
+        }
+
+        if (table) {
+                r = table_print(table, NULL);
+                if (r < 0)
+                        return table_log_print_error(r);
+        }
+
+        return ret;
+}
+
+static int show_group(GroupRecord *gr, Table *table) {
+        int r;
+
+        assert(gr);
+
+        switch (arg_output) {
+
+        case OUTPUT_CLASSIC: {
+                _cleanup_free_ char *m = NULL;
+
+                if (!gid_is_valid(gr->gid))
+                        break;
+
+                m = strv_join(gr->members, ",");
+                if (!m)
+                        return log_oom();
+
+                printf("%s:x:" GID_FMT ":%s\n",
+                       gr->group_name,
+                       gr->gid,
+                       m);
+                break;
+        }
+
+        case OUTPUT_JSON:
+                json_variant_dump(gr->json, JSON_FORMAT_COLOR_AUTO|JSON_FORMAT_PRETTY, NULL, 0);
+                break;
+
+        case OUTPUT_FRIENDLY:
+                group_record_show(gr, true);
+
+                if (gr->incomplete) {
+                        fflush(stdout);
+                        log_warning("Warning: lacking rights to acquire privileged fields of group record of '%s', output incomplete.", gr->group_name);
+                }
+
+                break;
+
+        case OUTPUT_TABLE:
+                assert(table);
+
+                r = table_add_many(
+                                table,
+                                TABLE_STRING, gr->group_name,
+                                TABLE_STRING, user_disposition_to_string(group_record_disposition(gr)),
+                                TABLE_GID, gr->gid,
+                                TABLE_STRING, gr->description,
+                                TABLE_INT, (int) group_record_disposition(gr));
+                if (r < 0)
+                        return table_log_add_error(r);
+
+                break;
+
+        default:
+                assert_not_reached("Unexpected display mode");
+        }
+
+        return 0;
+}
+
+
+static int display_group(int argc, char *argv[], void *userdata) {
+        _cleanup_(table_unrefp) Table *table = NULL;
+        bool draw_separator = false;
+        int ret = 0, r;
+
+        if (arg_output < 0)
+                arg_output = argc > 1 ? OUTPUT_FRIENDLY : OUTPUT_TABLE;
+
+        if (arg_output == OUTPUT_TABLE) {
+                table = table_new("name", "disposition", "gid", "description", "disposition-numeric");
+                if (!table)
+                        return log_oom();
+
+                (void) table_set_align_percent(table, table_get_cell(table, 0, 2), 100);
+                (void) table_set_empty_string(table, "-");
+                (void) table_set_sort(table, (size_t) 3, (size_t) 2, (size_t) -1);
+                (void) table_set_display(table, (size_t) 0, (size_t) 1, (size_t) 2, (size_t) 3, (size_t) -1);
+        }
+
+        if (argc > 1) {
+                char **i;
+
+                STRV_FOREACH(i, argv + 1) {
+                        _cleanup_(group_record_unrefp) GroupRecord *gr = NULL;
+                        gid_t gid;
+
+                        if (parse_gid(*i, &gid) >= 0)
+                                r = groupdb_by_gid(gid, arg_userdb_flags, &gr);
+                        else
+                                r = groupdb_by_name(*i, arg_userdb_flags, &gr);
+                        if (r < 0) {
+                                if (r == -ESRCH)
+                                        log_error_errno(r, "Group %s does not exist.", *i);
+                                else if (r == -EHOSTDOWN)
+                                        log_error_errno(r, "Selected group database service is not available for this request.");
+                                else
+                                        log_error_errno(r, "Failed to find group %s: %m", *i);
+
+                                if (ret >= 0)
+                                        ret = r;
+                        } else {
+                                if (draw_separator && arg_output == OUTPUT_FRIENDLY)
+                                        putchar('\n');
+
+                                r = show_group(gr, table);
+                                if (r < 0)
+                                        return r;
+
+                                draw_separator = true;
+                        }
+                }
+
+        } else {
+                _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+
+                r = groupdb_all(arg_userdb_flags, &iterator);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to enumerate groups: %m");
+
+                for (;;) {
+                        _cleanup_(group_record_unrefp) GroupRecord *gr = NULL;
+
+                        r = groupdb_iterator_get(iterator, &gr);
+                        if (r == -ESRCH)
+                                break;
+                        if (r == -EHOSTDOWN)
+                                return log_error_errno(r, "Selected group database service is not available for this request.");
+                        if (r < 0)
+                                return log_error_errno(r, "Failed acquire next group: %m");
+
+                        if (draw_separator && arg_output == OUTPUT_FRIENDLY)
+                                putchar('\n');
+
+                        r = show_group(gr, table);
+                        if (r < 0)
+                                return r;
+
+                        draw_separator = true;
+                }
+
+        }
+
+        if (table) {
+                r = table_print(table, NULL);
+                if (r < 0)
+                        return table_log_print_error(r);
+        }
+
+        return ret;
+}
+
+static int show_membership(const char *user, const char *group, Table *table) {
+        int r;
+
+        assert(user);
+        assert(group);
+
+        switch (arg_output) {
+
+        case OUTPUT_CLASSIC:
+                /* Strictly speaking there's no 'classic' output for this concept, but let's output it in
+                 * similar style to the classic output for user/group info */
+
+                printf("%s:%s\n", user, group);
+                break;
+
+        case OUTPUT_JSON: {
+                _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
+
+                r = json_build(&v, JSON_BUILD_OBJECT(
+                                               JSON_BUILD_PAIR("user", JSON_BUILD_STRING(user)),
+                                               JSON_BUILD_PAIR("group", JSON_BUILD_STRING(group))));
+                if (r < 0)
+                        return log_error_errno(r, "Failed to build JSON object: %m");
+
+                json_variant_dump(v, JSON_FORMAT_PRETTY|JSON_FORMAT_COLOR_AUTO, NULL, NULL);
+                break;
+        }
+
+        case OUTPUT_FRIENDLY:
+                /* Hmm, this is not particularly friendly, but not sure how we could do this better */
+                printf("%s: %s\n", group, user);
+                break;
+
+        case OUTPUT_TABLE:
+                assert(table);
+
+                r = table_add_many(
+                                table,
+                                TABLE_STRING, user,
+                                TABLE_STRING, group);
+                if (r < 0)
+                        return table_log_add_error(r);
+
+                break;
+
+        default:
+                assert_not_reached("Unexpected output mode");
+        }
+
+        return 0;
+}
+
+static int display_memberships(int argc, char *argv[], void *userdata) {
+        _cleanup_(table_unrefp) Table *table = NULL;
+        int ret = 0, r;
+
+        if (arg_output < 0)
+                arg_output = OUTPUT_TABLE;
+
+        if (arg_output == OUTPUT_TABLE) {
+                table = table_new("user", "group");
+                if (!table)
+                        return log_oom();
+
+                (void) table_set_sort(table, (size_t) 0, (size_t) 1, (size_t) -1);
+        }
+
+        if (argc > 1) {
+                char **i;
+
+                STRV_FOREACH(i, argv + 1) {
+                        _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+
+                        if (streq(argv[0], "users-in-group")) {
+                                r = membershipdb_by_group(*i, arg_userdb_flags, &iterator);
+                                if (r < 0)
+                                        return log_error_errno(r, "Failed to enumerate users in group: %m");
+                        } else if (streq(argv[0], "groups-of-user")) {
+                                r = membershipdb_by_user(*i, arg_userdb_flags, &iterator);
+                                if (r < 0)
+                                        return log_error_errno(r, "Failed to enumerate groups of user: %m");
+                        } else
+                                assert_not_reached("Unexpected verb");
+
+                        for (;;) {
+                                _cleanup_free_ char *user = NULL, *group = NULL;
+
+                                r = membershipdb_iterator_get(iterator, &user, &group);
+                                if (r == -ESRCH)
+                                        break;
+                                if (r == -EHOSTDOWN)
+                                        return log_error_errno(r, "Selected membership database service is not available for this request.");
+                                if (r < 0)
+                                        return log_error_errno(r, "Failed acquire next membership: %m");
+
+                                r = show_membership(user, group, table);
+                                if (r < 0)
+                                        return r;
+                        }
+                }
+        } else {
+                _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+
+                r = membershipdb_all(arg_userdb_flags, &iterator);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to enumerate memberships: %m");
+
+                for (;;) {
+                        _cleanup_free_ char *user = NULL, *group = NULL;
+
+                        r = membershipdb_iterator_get(iterator, &user, &group);
+                        if (r == -ESRCH)
+                                break;
+                        if (r == -EHOSTDOWN)
+                                return log_error_errno(r, "Selected membership database service is not available for this request.");
+                        if (r < 0)
+                                return log_error_errno(r, "Failed acquire next membership: %m");
+
+                        r = show_membership(user, group, table);
+                        if (r < 0)
+                                return r;
+                }
+        }
+
+        if (table) {
+                r = table_print(table, NULL);
+                if (r < 0)
+                        return table_log_print_error(r);
+        }
+
+        return ret;
+}
+
+static int display_services(int argc, char *argv[], void *userdata) {
+        _cleanup_(table_unrefp) Table *t = NULL;
+        _cleanup_(closedirp) DIR *d = NULL;
+        struct dirent *de;
+        int r;
+
+        d = opendir("/run/systemd/userdb/");
+        if (!d) {
+                if (errno == ENOENT) {
+                        log_info("No services.");
+                        return 0;
+                }
+
+                return log_error_errno(errno, "Failed to open /run/systemd/userdb/: %m");
+        }
+
+        t = table_new("service", "listening");
+        if (!t)
+                return log_oom();
+
+        (void) table_set_sort(t, (size_t) 0, (size_t) -1);
+
+        FOREACH_DIRENT(de, d, return -errno) {
+                _cleanup_free_ char *j = NULL, *no = NULL;
+                union sockaddr_union sockaddr;
+                socklen_t sockaddr_len;
+                _cleanup_close_ int fd = -1;
+
+                j = path_join("/run/systemd/userdb/", de->d_name);
+                if (!j)
+                        return log_oom();
+
+                r = sockaddr_un_set_path(&sockaddr.un, j);
+                if (r < 0)
+                        return log_error_errno(r, "Path %s does not fit in AF_UNIX socket address: %m", j);
+                sockaddr_len = r;
+
+                fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+                if (fd < 0)
+                        return log_error_errno(r, "Failed to allocate AF_UNIX/SOCK_STREAM socket: %m");
+
+                if (connect(fd, &sockaddr.un, sockaddr_len) < 0) {
+                        no = strjoin("No (", errno_to_name(errno), ")");
+                        if (!no)
+                                return log_oom();
+                }
+
+                r = table_add_many(t,
+                                   TABLE_STRING, de->d_name,
+                                   TABLE_STRING, no ?: "yes",
+                                   TABLE_SET_COLOR, no ? ansi_highlight_red() : ansi_highlight_green());
+                if (r < 0)
+                        return table_log_add_error(r);
+        }
+
+        if (table_get_rows(t) <= 0) {
+                log_info("No services.");
+                return 0;
+        }
+
+        if (arg_output == OUTPUT_JSON)
+                table_print_json(t, NULL, JSON_FORMAT_PRETTY|JSON_FORMAT_COLOR_AUTO);
+        else
+                table_print(t, NULL);
+
+        return 0;
+}
+
+static int ssh_authorized_keys(int argc, char *argv[], void *userdata) {
+        _cleanup_(user_record_unrefp) UserRecord *ur = NULL;
+        int r;
+
+        r = userdb_by_name(argv[1], arg_userdb_flags, &ur);
+        if (r == -ESRCH)
+                return log_error_errno(r, "User %s does not exist.", argv[1]);
+        else if (r == -EHOSTDOWN)
+                return log_error_errno(r, "Selected user database service is not available for this request.");
+        else if (r == -EINVAL)
+                return log_error_errno(r, "Failed to find user %s: %m (Invalid user name?)", argv[1]);
+        else if (r < 0)
+                return log_error_errno(r, "Failed to find user %s: %m", argv[1]);
+
+        if (strv_isempty(ur->ssh_authorized_keys))
+                log_debug("User record for %s has no public SSH keys.", argv[1]);
+        else {
+                char **i;
+
+                STRV_FOREACH(i, ur->ssh_authorized_keys)
+                        printf("%s\n", *i);
+        }
+
+        if (ur->incomplete) {
+                fflush(stdout);
+                log_warning("Warning: lacking rights to acquire privileged fields of user record of '%s', output incomplete.", ur->user_name);
+        }
+
+        return EXIT_SUCCESS;
+}
+
+static int help(int argc, char *argv[], void *userdata) {
+        _cleanup_free_ char *link = NULL;
+        int r;
+
+        (void) pager_open(arg_pager_flags);
+
+        r = terminal_urlify_man("userdbctl", "1", &link);
+        if (r < 0)
+                return log_oom();
+
+        printf("%s [OPTIONS...] COMMAND ...\n\n"
+               "%sShow user and group information.%s\n"
+               "\nCommands:\n"
+               "  user [USER…]               Inspect user\n"
+               "  group [GROUP…]             Inspect group\n"
+               "  users-in-group [GROUP…]    Show users that are members of specified group(s)\n"
+               "  groups-of-user [USER…]     Show groups the specified user(s) is a member of\n"
+               "  services                   Show enabled database services\n"
+               "\nOptions:\n"
+               "  -h --help                  Show this help\n"
+               "     --version               Show package version\n"
+               "     --no-pager              Do not pipe output into a pager\n"
+               "     --no-legend             Do not show the headers and footers\n"
+               "     --output=MODE           Select output mode (classic, friendly, table, json)\n"
+               "  -j                         Equivalent to --output=json\n"
+               "  -s --service=SERVICE[:SERVICE…]\n"
+               "                             Query the specified service\n"
+               "     --with-nss=BOOL         Control whether to include glibc NSS data\n"
+               "  -N                         Do not synthesize or include glibc NSS data\n"
+               "                             (Same as --synthesize=no --with-nss=no)\n"
+               "     --synthesize=BOOL       Synthesize root/nobody user\n"
+               "\nSee the %s for details.\n"
+               , program_invocation_short_name
+               , ansi_highlight(), ansi_normal()
+               , link
+        );
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+
+        enum {
+                ARG_VERSION = 0x100,
+                ARG_NO_PAGER,
+                ARG_NO_LEGEND,
+                ARG_OUTPUT,
+                ARG_WITH_NSS,
+                ARG_SYNTHESIZE,
+        };
+
+        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  },
+                { "output",     required_argument, NULL, ARG_OUTPUT     },
+                { "service",    required_argument, NULL, 's'            },
+                { "with-nss",   required_argument, NULL, ARG_WITH_NSS   },
+                { "synthesize", required_argument, NULL, ARG_SYNTHESIZE },
+                {}
+        };
+
+        const char *e;
+        int r;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        /* We are going to update this environment variable with our own, hence let's first read what is already set */
+        e = getenv("SYSTEMD_ONLY_USERDB");
+        if (e) {
+                char **l;
+
+                l = strv_split(e, ":");
+                if (!l)
+                        return log_oom();
+
+                strv_free(arg_services);
+                arg_services = l;
+        }
+
+        for (;;) {
+                int c;
+
+                c = getopt_long(argc, argv, "hjs:N", options, NULL);
+                if (c < 0)
+                        break;
+
+                switch (c) {
+
+                case 'h':
+                        return help(0, NULL, NULL);
+
+                case ARG_VERSION:
+                        return version();
+
+                case ARG_NO_PAGER:
+                        arg_pager_flags |= PAGER_DISABLE;
+                        break;
+
+                case ARG_NO_LEGEND:
+                        arg_legend = false;
+                        break;
+
+                case ARG_OUTPUT:
+                        if (streq(optarg, "classic"))
+                                arg_output = OUTPUT_CLASSIC;
+                        else if (streq(optarg, "friendly"))
+                                arg_output = OUTPUT_FRIENDLY;
+                        else if (streq(optarg, "json"))
+                                arg_output = OUTPUT_JSON;
+                        else if (streq(optarg, "table"))
+                                arg_output = OUTPUT_TABLE;
+                        else if (streq(optarg, "help")) {
+                                puts("classic\n"
+                                     "friendly\n"
+                                     "json\n"
+                                     "table");
+                                return 0;
+                        } else
+                                return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Invalid --output= mode: %s", optarg);
+
+                        break;
+
+                case 'j':
+                        arg_output = OUTPUT_JSON;
+                        break;
+
+                case 's':
+                        if (isempty(optarg))
+                                arg_services = strv_free(arg_services);
+                        else {
+                                _cleanup_strv_free_ char **l = NULL;
+
+                                l = strv_split(optarg, ":");
+                                if (!l)
+                                        return log_oom();
+
+                                r = strv_extend_strv(&arg_services, l, true);
+                                if (r < 0)
+                                        return log_oom();
+                        }
+
+                        break;
+
+                case 'N':
+                        arg_userdb_flags |= USERDB_AVOID_NSS|USERDB_DONT_SYNTHESIZE;
+                        break;
+
+                case ARG_WITH_NSS:
+                        r = parse_boolean(optarg);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to parse --with-nss= parameter: %s", optarg);
+
+                        SET_FLAG(arg_userdb_flags, USERDB_AVOID_NSS, !r);
+                        break;
+
+                case ARG_SYNTHESIZE:
+                        r = parse_boolean(optarg);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to parse --synthesize= parameter: %s", optarg);
+
+                        SET_FLAG(arg_userdb_flags, USERDB_DONT_SYNTHESIZE, !r);
+                        break;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        assert_not_reached("Unhandled option");
+                }
+        }
+
+        return 1;
+}
+
+static int run(int argc, char *argv[]) {
+        static const Verb verbs[] = {
+                { "help",                VERB_ANY, VERB_ANY, 0,            help                },
+                { "user",                VERB_ANY, VERB_ANY, VERB_DEFAULT, display_user        },
+                { "group",               VERB_ANY, VERB_ANY, 0,            display_group       },
+                { "users-in-group",      VERB_ANY, VERB_ANY, 0,            display_memberships },
+                { "groups-of-user",      VERB_ANY, VERB_ANY, 0,            display_memberships },
+                { "services",            VERB_ANY, 1,        0,            display_services    },
+
+                /* This one is a helper for sshd_config's AuthorizedKeysCommand= setting, it's not a
+                 * user-facing verb and thus should not appear in man pages or --help texts. */
+                { "ssh-authorized-keys", 2,        2,        0,            ssh_authorized_keys },
+                {}
+        };
+
+        int r;
+
+        log_setup_cli();
+
+        r = parse_argv(argc, argv);
+        if (r <= 0)
+                return r;
+
+        if (arg_services) {
+                _cleanup_free_ char *e = NULL;
+
+                e = strv_join(arg_services, ":");
+                if (!e)
+                        return log_oom();
+
+                if (setenv("SYSTEMD_ONLY_USERDB", e, true) < 0)
+                        return log_error_errno(r, "Failed to set $SYSTEMD_ONLY_USERDB: %m");
+
+                log_info("Enabled services: %s", e);
+        } else
+                assert_se(unsetenv("SYSTEMD_ONLY_USERDB") == 0);
+
+        return dispatch_verb(argc, argv, verbs, NULL);
+}
+
+DEFINE_MAIN_FUNCTION(run);
diff --git a/src/userdb/userdbd-manager.c b/src/userdb/userdbd-manager.c
new file mode 100644
index 0000000..f8d315c
--- /dev/null
+++ b/src/userdb/userdbd-manager.c
@@ -0,0 +1,301 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sys/wait.h>
+
+#include "sd-daemon.h"
+
+#include "fd-util.h"
+#include "fs-util.h"
+#include "mkdir.h"
+#include "process-util.h"
+#include "set.h"
+#include "signal-util.h"
+#include "socket-util.h"
+#include "stdio-util.h"
+#include "umask-util.h"
+#include "userdbd-manager.h"
+
+#define LISTEN_TIMEOUT_USEC (25 * USEC_PER_SEC)
+
+static int start_workers(Manager *m, bool explicit_request);
+
+static int on_sigchld(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
+        Manager *m = userdata;
+
+        assert(s);
+        assert(m);
+
+        for (;;) {
+                siginfo_t siginfo = {};
+                bool removed = false;
+
+                if (waitid(P_ALL, 0, &siginfo, WNOHANG|WEXITED) < 0) {
+                        if (errno == ECHILD)
+                                break;
+
+                        log_warning_errno(errno, "Failed to invoke waitid(): %m");
+                        break;
+                }
+                if (siginfo.si_pid == 0)
+                        break;
+
+                if (set_remove(m->workers_dynamic, PID_TO_PTR(siginfo.si_pid)))
+                        removed = true;
+                if (set_remove(m->workers_fixed, PID_TO_PTR(siginfo.si_pid)))
+                        removed = true;
+
+                if (!removed) {
+                        log_warning("Weird, got SIGCHLD for unknown child " PID_FMT ", ignoring.", siginfo.si_pid);
+                        continue;
+                }
+
+                if (siginfo.si_code == CLD_EXITED) {
+                        if (siginfo.si_status == EXIT_SUCCESS)
+                                log_debug("Worker " PID_FMT " exited successfully.", siginfo.si_pid);
+                        else
+                                log_warning("Worker " PID_FMT " died with a failure exit status %i, ignoring.", siginfo.si_pid, siginfo.si_status);
+                } else if (siginfo.si_code == CLD_KILLED)
+                        log_warning("Worker " PID_FMT " was killed by signal %s, ignoring.", siginfo.si_pid, signal_to_string(siginfo.si_status));
+                else if (siginfo.si_code == CLD_DUMPED)
+                        log_warning("Worker " PID_FMT " dumped core by signal %s, ignoring.", siginfo.si_pid, signal_to_string(siginfo.si_status));
+                else
+                        log_warning("Can't handle SIGCHLD of this type");
+        }
+
+        (void) start_workers(m, false); /* Fill up workers again if we fell below the low watermark */
+        return 0;
+}
+
+static int on_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
+        Manager *m = userdata;
+
+        assert(s);
+        assert(m);
+
+        (void) start_workers(m, true); /* Workers told us there's more work, let's add one more worker as long as we are below the high watermark */
+        return 0;
+}
+
+int manager_new(Manager **ret) {
+        _cleanup_(manager_freep) Manager *m = NULL;
+        int r;
+
+        m = new(Manager, 1);
+        if (!m)
+                return -ENOMEM;
+
+        *m = (Manager) {
+                .listen_fd = -1,
+                .worker_ratelimit = {
+                        .interval = 5 * USEC_PER_SEC,
+                        .burst = 50,
+                },
+        };
+
+        r = sd_event_new(&m->event);
+        if (r < 0)
+                return r;
+
+        r = sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
+        if (r < 0)
+                return r;
+
+        r = sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
+        if (r < 0)
+                return r;
+
+        (void) sd_event_set_watchdog(m->event, true);
+
+        m->workers_fixed = set_new(NULL);
+        m->workers_dynamic = set_new(NULL);
+
+        if (!m->workers_fixed || !m->workers_dynamic)
+                return -ENOMEM;
+
+        r = sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, on_sigusr2, m);
+        if (r < 0)
+                return r;
+
+        r = sd_event_add_signal(m->event, &m->sigchld_event_source, SIGCHLD, on_sigchld, m);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(m);
+        return 0;
+}
+
+Manager* manager_free(Manager *m) {
+        if (!m)
+                return NULL;
+
+        set_free(m->workers_fixed);
+        set_free(m->workers_dynamic);
+
+        sd_event_source_disable_unref(m->sigusr2_event_source);
+        sd_event_source_disable_unref(m->sigchld_event_source);
+
+        sd_event_unref(m->event);
+
+        return mfree(m);
+}
+
+static size_t manager_current_workers(Manager *m) {
+        assert(m);
+
+        return set_size(m->workers_fixed) + set_size(m->workers_dynamic);
+}
+
+static int start_one_worker(Manager *m) {
+        bool fixed;
+        pid_t pid;
+        int r;
+
+        assert(m);
+
+        fixed = set_size(m->workers_fixed) < USERDB_WORKERS_MIN;
+
+        r = safe_fork("(sd-worker)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
+        if (r < 0)
+                return log_error_errno(r, "Failed to fork new worker child: %m");
+        if (r == 0) {
+                char pids[DECIMAL_STR_MAX(pid_t)];
+                /* Child */
+
+                log_close();
+
+                r = close_all_fds(&m->listen_fd, 1);
+                if (r < 0) {
+                        log_error_errno(r, "Failed to close fds in child: %m");
+                        _exit(EXIT_FAILURE);
+                }
+
+                log_open();
+
+                if (m->listen_fd == 3) {
+                        r = fd_cloexec(3, false);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to turn off O_CLOEXEC for fd 3: %m");
+                                _exit(EXIT_FAILURE);
+                        }
+                } else {
+                        if (dup2(m->listen_fd, 3) < 0) { /* dup2() creates with O_CLOEXEC off */
+                                log_error_errno(errno, "Failed to move listen fd to 3: %m");
+                                _exit(EXIT_FAILURE);
+                        }
+
+                        safe_close(m->listen_fd);
+                }
+
+                xsprintf(pids, PID_FMT, pid);
+                if (setenv("LISTEN_PID", pids, 1) < 0) {
+                        log_error_errno(errno, "Failed to set $LISTEN_PID: %m");
+                        _exit(EXIT_FAILURE);
+                }
+
+                if (setenv("LISTEN_FDS", "1", 1) < 0) {
+                        log_error_errno(errno, "Failed to set $LISTEN_FDS: %m");
+                        _exit(EXIT_FAILURE);
+                }
+
+
+                if (setenv("USERDB_FIXED_WORKER", one_zero(fixed), 1) < 0) {
+                        log_error_errno(errno, "Failed to set $USERDB_FIXED_WORKER: %m");
+                        _exit(EXIT_FAILURE);
+                }
+
+                /* execl("/home/lennart/projects/systemd/build/systemd-userwork", "systemd-userwork", "xxxxxxxxxxxxxxxx", NULL); /\* With some extra space rename_process() can make use of *\/ */
+                /* execl("/usr/bin/valgrind", "valgrind", "/home/lennart/projects/systemd/build/systemd-userwork", "systemd-userwork", "xxxxxxxxxxxxxxxx", NULL); /\* With some extra space rename_process() can make use of *\/ */
+
+                execl(SYSTEMD_USERWORK_PATH, "systemd-userwork", "xxxxxxxxxxxxxxxx", NULL); /* With some extra space rename_process() can make use of */
+                log_error_errno(errno, "Failed start worker process: %m");
+                _exit(EXIT_FAILURE);
+        }
+
+        if (fixed)
+                r = set_put(m->workers_fixed, PID_TO_PTR(pid));
+        else
+                r = set_put(m->workers_dynamic, PID_TO_PTR(pid));
+        if (r < 0)
+                return log_error_errno(r, "Failed to add child process to set: %m");
+
+        return 0;
+}
+
+static int start_workers(Manager *m, bool explicit_request) {
+        int r;
+
+        assert(m);
+
+        for (;;)  {
+                size_t n;
+
+                n = manager_current_workers(m);
+                if (n >= USERDB_WORKERS_MIN && (!explicit_request || n >= USERDB_WORKERS_MAX))
+                        break;
+
+                if (!ratelimit_below(&m->worker_ratelimit)) {
+                        /* If we keep starting workers too often, let's fail the whole daemon, something is wrong */
+                        sd_event_exit(m->event, EXIT_FAILURE);
+
+                        return log_error_errno(SYNTHETIC_ERRNO(EUCLEAN), "Worker threads requested too frequently, something is wrong.");
+                }
+
+                r = start_one_worker(m);
+                if (r < 0)
+                        return r;
+
+                explicit_request = false;
+        }
+
+        return 0;
+}
+
+int manager_startup(Manager *m) {
+        struct timeval ts;
+        int n, r;
+
+        assert(m);
+        assert(m->listen_fd < 0);
+
+        n = sd_listen_fds(false);
+        if (n < 0)
+                return log_error_errno(n, "Failed to determine number of passed file descriptors: %m");
+        if (n > 1)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Expected one listening fd, got %i.", n);
+        if (n == 1)
+                m->listen_fd = SD_LISTEN_FDS_START;
+        else {
+                union sockaddr_union sockaddr = {
+                        .un.sun_family = AF_UNIX,
+                        .un.sun_path = "/run/systemd/userdb/io.systemd.NameServiceSwitch",
+                };
+
+                r = mkdir_p("/run/systemd/userdb", 0755);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to create /run/systemd/userdb: %m");
+
+                m->listen_fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
+                if (m->listen_fd < 0)
+                        return log_error_errno(errno, "Failed to bind on socket: %m");
+
+                (void) sockaddr_un_unlink(&sockaddr.un);
+
+                RUN_WITH_UMASK(0000)
+                        if (bind(m->listen_fd, &sockaddr.sa, SOCKADDR_UN_LEN(sockaddr.un)) < 0)
+                                return log_error_errno(errno, "Failed to bind socket: %m");
+
+                r = symlink_idempotent("io.systemd.NameServiceSwitch", "/run/systemd/userdb/io.systemd.Multiplexer", false);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to bind io.systemd.Multiplexer: %m");
+
+                if (listen(m->listen_fd, SOMAXCONN) < 0)
+                        return log_error_errno(errno, "Failed to listen on socket: %m");
+        }
+
+        /* Let's make sure every accept() call on this socket times out after 25s. This allows workers to be
+         * GC'ed on idle */
+        if (setsockopt(m->listen_fd, SOL_SOCKET, SO_RCVTIMEO, timeval_store(&ts, LISTEN_TIMEOUT_USEC), sizeof(ts)) < 0)
+                return log_error_errno(errno, "Failed to se SO_RCVTIMEO: %m");
+
+        return start_workers(m, false);
+}
diff --git a/src/userdb/userdbd-manager.h b/src/userdb/userdbd-manager.h
new file mode 100644
index 0000000..b81615a
--- /dev/null
+++ b/src/userdb/userdbd-manager.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include "sd-bus.h"
+#include "sd-event.h"
+
+typedef struct Manager Manager;
+
+#include "hashmap.h"
+#include "varlink.h"
+#include "ratelimit.h"
+
+#define USERDB_WORKERS_MIN 3
+#define USERDB_WORKERS_MAX 4096
+
+struct Manager {
+        sd_event *event;
+
+        Set *workers_fixed;    /* Workers 0…USERDB_WORKERS_MIN */
+        Set *workers_dynamic;  /* Workers USERD_WORKERS_MIN+1…USERDB_WORKERS_MAX */
+
+        sd_event_source *sigusr2_event_source;
+        sd_event_source *sigchld_event_source;
+
+        int listen_fd;
+
+        RateLimit worker_ratelimit;
+};
+
+int manager_new(Manager **ret);
+Manager* manager_free(Manager *m);
+DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free);
+
+int manager_startup(Manager *m);
diff --git a/src/userdb/userdbd.c b/src/userdb/userdbd.c
new file mode 100644
index 0000000..6f2c807
--- /dev/null
+++ b/src/userdb/userdbd.c
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "daemon-util.h"
+#include "userdbd-manager.h"
+#include "log.h"
+#include "main-func.h"
+#include "signal-util.h"
+
+/* This service offers two Varlink services, both implementing io.systemd.UserDatabase:
+ *
+ *         → io.systemd.NameServiceSwitch: this is a compatibility interface for glibc NSS: it responds to
+ *           name lookups by checking the classic NSS interfaces and responding that.
+ *
+ *         → io.systemd.Multiplexer: this multiplexes lookup requests to all Varlink services that have a
+ *           socket in /run/systemd/userdb/. It's supposed to simplify clients that don't want to implement
+ *           the full iterative logic on their own.
+ */
+
+static int run(int argc, char *argv[]) {
+        _cleanup_(manager_freep) Manager *m = NULL;
+        _cleanup_(notify_on_cleanup) const char *notify_stop = NULL;
+        int r;
+
+        log_setup_service();
+
+        umask(0022);
+
+        if (argc != 1)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "This program takes no arguments.");
+
+        if (setenv("SYSTEMD_BYPASS_USERDB", "io.systemd.NameServiceSwitch:io.systemd.Multiplexer", 1) < 0)
+                return log_error_errno(errno, "Failed to se $SYSTEMD_BYPASS_USERDB: %m");
+
+        assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGCHLD, SIGTERM, SIGINT, SIGUSR2, -1) >= 0);
+
+        r = manager_new(&m);
+        if (r < 0)
+                return log_error_errno(r, "Could not create manager: %m");
+
+        r = manager_startup(m);
+        if (r < 0)
+                return log_error_errno(r, "Failed to start up daemon: %m");
+
+        notify_stop = notify_start(NOTIFY_READY, NOTIFY_STOPPING);
+
+        r = sd_event_loop(m->event);
+        if (r < 0)
+                return log_error_errno(r, "Event loop failed: %m");
+
+        return 0;
+}
+
+DEFINE_MAIN_FUNCTION(run);
diff --git a/src/userdb/userwork.c b/src/userdb/userwork.c
new file mode 100644
index 0000000..d525a6e
--- /dev/null
+++ b/src/userdb/userwork.c
@@ -0,0 +1,775 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <poll.h>
+#include <sys/wait.h>
+
+#include "sd-daemon.h"
+
+#include "env-util.h"
+#include "fd-util.h"
+#include "group-record.h"
+#include "io-util.h"
+#include "main-func.h"
+#include "process-util.h"
+#include "strv.h"
+#include "time-util.h"
+#include "user-record-nss.h"
+#include "user-record.h"
+#include "user-util.h"
+#include "userdb.h"
+#include "varlink.h"
+
+#define ITERATIONS_MAX 64U
+#define RUNTIME_MAX_USEC (5 * USEC_PER_MINUTE)
+#define PRESSURE_SLEEP_TIME_USEC (50 * USEC_PER_MSEC)
+#define CONNECTION_IDLE_USEC (15 * USEC_PER_SEC)
+#define LISTEN_IDLE_USEC (90 * USEC_PER_SEC)
+
+typedef struct LookupParameters {
+        const char *user_name;
+        const char *group_name;
+        union {
+                uid_t uid;
+                gid_t gid;
+        };
+        const char *service;
+} LookupParameters;
+
+static int add_nss_service(JsonVariant **v) {
+        _cleanup_(json_variant_unrefp) JsonVariant *status = NULL, *z = NULL;
+        char buf[SD_ID128_STRING_MAX];
+        sd_id128_t mid;
+        int r;
+
+        assert(v);
+
+        /* Patch in service field if it's missing. The assumption here is that this field is unset only for
+         * NSS records */
+
+        if (json_variant_by_key(*v, "service"))
+                return 0;
+
+        r = sd_id128_get_machine(&mid);
+        if (r < 0)
+                return r;
+
+        status = json_variant_ref(json_variant_by_key(*v, "status"));
+        z = json_variant_ref(json_variant_by_key(status, sd_id128_to_string(mid, buf)));
+
+        if (json_variant_by_key(z, "service"))
+                return 0;
+
+        r = json_variant_set_field_string(&z, "service", "io.systemd.NameServiceSwitch");
+        if (r < 0)
+                return r;
+
+        r = json_variant_set_field(&status, buf, z);
+        if (r < 0)
+                return r;
+
+        return json_variant_set_field(v, "status", status);
+}
+
+static int build_user_json(Varlink *link, UserRecord *ur, JsonVariant **ret) {
+        _cleanup_(user_record_unrefp) UserRecord *stripped = NULL;
+        _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
+        UserRecordLoadFlags flags;
+        uid_t peer_uid;
+        bool trusted;
+        int r;
+
+        assert(ur);
+        assert(ret);
+
+        r = varlink_get_peer_uid(link, &peer_uid);
+        if (r < 0) {
+                log_debug_errno(r, "Unable to query peer UID, ignoring: %m");
+                trusted = false;
+        } else
+                trusted = peer_uid == 0 || peer_uid == ur->uid;
+
+        flags = USER_RECORD_REQUIRE_REGULAR|USER_RECORD_ALLOW_PER_MACHINE|USER_RECORD_ALLOW_BINDING|USER_RECORD_STRIP_SECRET|USER_RECORD_ALLOW_STATUS|USER_RECORD_ALLOW_SIGNATURE;
+        if (trusted)
+                flags |= USER_RECORD_ALLOW_PRIVILEGED;
+        else
+                flags |= USER_RECORD_STRIP_PRIVILEGED;
+
+        r = user_record_clone(ur, flags, &stripped);
+        if (r < 0)
+                return r;
+
+        stripped->incomplete =
+                ur->incomplete ||
+                (FLAGS_SET(ur->mask, USER_RECORD_PRIVILEGED) &&
+                 !FLAGS_SET(stripped->mask, USER_RECORD_PRIVILEGED));
+
+        v = json_variant_ref(stripped->json);
+        r = add_nss_service(&v);
+        if (r < 0)
+                return r;
+
+        return json_build(ret, JSON_BUILD_OBJECT(
+                                          JSON_BUILD_PAIR("record", JSON_BUILD_VARIANT(v)),
+                                          JSON_BUILD_PAIR("incomplete", JSON_BUILD_BOOLEAN(stripped->incomplete))));
+}
+
+static int vl_method_get_user_record(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
+
+        static const JsonDispatch dispatch_table[] = {
+                { "uid",      JSON_VARIANT_UNSIGNED, json_dispatch_uid_gid,      offsetof(LookupParameters, uid),       0 },
+                { "userName", JSON_VARIANT_STRING,   json_dispatch_const_string, offsetof(LookupParameters, user_name), 0 },
+                { "service",  JSON_VARIANT_STRING,   json_dispatch_const_string, offsetof(LookupParameters, service),   0 },
+                {}
+        };
+
+        _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
+        _cleanup_(user_record_unrefp) UserRecord *hr = NULL;
+        LookupParameters p = {
+                .uid = UID_INVALID,
+        };
+        int r;
+
+        assert(parameters);
+
+        r = json_dispatch(parameters, dispatch_table, NULL, 0, &p);
+        if (r < 0)
+                return r;
+
+        if (streq_ptr(p.service, "io.systemd.NameServiceSwitch")) {
+                if (uid_is_valid(p.uid))
+                        r = nss_user_record_by_uid(p.uid, true, &hr);
+                else if (p.user_name)
+                        r = nss_user_record_by_name(p.user_name, true, &hr);
+                else {
+                        _cleanup_(json_variant_unrefp) JsonVariant *last = NULL;
+
+                        setpwent();
+
+                        for (;;) {
+                                _cleanup_(user_record_unrefp) UserRecord *z = NULL;
+                                _cleanup_free_ char *sbuf = NULL;
+                                struct passwd *pw;
+                                struct spwd spwd;
+
+                                errno = 0;
+                                pw = getpwent();
+                                if (!pw) {
+                                        if (errno != 0)
+                                                log_debug_errno(errno, "Failure while iterating through NSS user database, ignoring: %m");
+
+                                        break;
+                                }
+
+                                r = nss_spwd_for_passwd(pw, &spwd, &sbuf);
+                                if (r < 0)
+                                        log_debug_errno(r, "Failed to acquire shadow entry for user %s, ignoring: %m", pw->pw_name);
+
+                                r = nss_passwd_to_user_record(pw, NULL, &z);
+                                if (r < 0) {
+                                        endpwent();
+                                        return r;
+                                }
+
+                                if (last) {
+                                        r = varlink_notify(link, last);
+                                        if (r < 0) {
+                                                endpwent();
+                                                return r;
+                                        }
+
+                                        last = json_variant_unref(last);
+                                }
+
+                                r = build_user_json(link, z, &last);
+                                if (r < 0) {
+                                        endpwent();
+                                        return r;
+                                }
+                        }
+
+                        endpwent();
+
+                        if (!last)
+                                return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+
+                        return varlink_reply(link, last);
+                }
+
+        } else if (streq_ptr(p.service, "io.systemd.Multiplexer")) {
+
+                if (uid_is_valid(p.uid))
+                        r = userdb_by_uid(p.uid, USERDB_AVOID_MULTIPLEXER, &hr);
+                else if (p.user_name)
+                        r = userdb_by_name(p.user_name, USERDB_AVOID_MULTIPLEXER, &hr);
+                else {
+                        _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+                        _cleanup_(json_variant_unrefp) JsonVariant *last = NULL;
+
+                        r = userdb_all(USERDB_AVOID_MULTIPLEXER, &iterator);
+                        if (r < 0)
+                                return r;
+
+                        for (;;) {
+                                _cleanup_(user_record_unrefp) UserRecord *z = NULL;
+
+                                r = userdb_iterator_get(iterator, &z);
+                                if (r == -ESRCH)
+                                        break;
+                                if (r < 0)
+                                        return r;
+
+                                if (last) {
+                                        r = varlink_notify(link, last);
+                                        if (r < 0)
+                                                return r;
+
+                                        last = json_variant_unref(last);
+                                }
+
+                                r = build_user_json(link, z, &last);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        if (!last)
+                                return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+
+                        return varlink_reply(link, last);
+                }
+        } else
+                return varlink_error(link, "io.systemd.UserDatabase.BadService", NULL);
+        if (r == -ESRCH)
+                return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+        if (r < 0) {
+                log_debug_errno(r, "User lookup failed abnormally: %m");
+                return varlink_error(link, "io.systemd.UserDatabase.ServiceNotAvailable", NULL);
+        }
+
+        if ((uid_is_valid(p.uid) && hr->uid != p.uid) ||
+            (p.user_name && !streq(hr->user_name, p.user_name)))
+                return varlink_error(link, "io.systemd.UserDatabase.ConflictingRecordFound", NULL);
+
+        r = build_user_json(link, hr, &v);
+        if (r < 0)
+                return r;
+
+        return varlink_reply(link, v);
+}
+
+static int build_group_json(Varlink *link, GroupRecord *gr, JsonVariant **ret) {
+        _cleanup_(group_record_unrefp) GroupRecord *stripped = NULL;
+        _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
+        UserRecordLoadFlags flags;
+        uid_t peer_uid;
+        bool trusted;
+        int r;
+
+        assert(gr);
+        assert(ret);
+
+        r = varlink_get_peer_uid(link, &peer_uid);
+        if (r < 0) {
+                log_debug_errno(r, "Unable to query peer UID, ignoring: %m");
+                trusted = false;
+        } else
+                trusted = peer_uid == 0;
+
+        flags = USER_RECORD_REQUIRE_REGULAR|USER_RECORD_ALLOW_PER_MACHINE|USER_RECORD_ALLOW_BINDING|USER_RECORD_STRIP_SECRET|USER_RECORD_ALLOW_STATUS|USER_RECORD_ALLOW_SIGNATURE;
+        if (trusted)
+                flags |= USER_RECORD_ALLOW_PRIVILEGED;
+        else
+                flags |= USER_RECORD_STRIP_PRIVILEGED;
+
+        r = group_record_clone(gr, flags, &stripped);
+        if (r < 0)
+                return r;
+
+        stripped->incomplete =
+                gr->incomplete ||
+                (FLAGS_SET(gr->mask, USER_RECORD_PRIVILEGED) &&
+                 !FLAGS_SET(stripped->mask, USER_RECORD_PRIVILEGED));
+
+        v = json_variant_ref(gr->json);
+        r = add_nss_service(&v);
+        if (r < 0)
+                return r;
+
+        return json_build(ret, JSON_BUILD_OBJECT(
+                                          JSON_BUILD_PAIR("record", JSON_BUILD_VARIANT(v)),
+                                          JSON_BUILD_PAIR("incomplete", JSON_BUILD_BOOLEAN(stripped->incomplete))));
+}
+
+static int vl_method_get_group_record(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
+
+        static const JsonDispatch dispatch_table[] = {
+                { "gid",       JSON_VARIANT_UNSIGNED, json_dispatch_uid_gid,      offsetof(LookupParameters, gid),        0 },
+                { "groupName", JSON_VARIANT_STRING,   json_dispatch_const_string, offsetof(LookupParameters, group_name), 0 },
+                { "service",   JSON_VARIANT_STRING,   json_dispatch_const_string, offsetof(LookupParameters, service),    0 },
+                {}
+        };
+
+        _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
+        _cleanup_(group_record_unrefp) GroupRecord *g = NULL;
+        LookupParameters p = {
+                .gid = GID_INVALID,
+        };
+        int r;
+
+        assert(parameters);
+
+        r = json_dispatch(parameters, dispatch_table, NULL, 0, &p);
+        if (r < 0)
+                return r;
+
+        if (streq_ptr(p.service, "io.systemd.NameServiceSwitch")) {
+
+                if (gid_is_valid(p.gid))
+                        r = nss_group_record_by_gid(p.gid, true, &g);
+                else if (p.group_name)
+                        r = nss_group_record_by_name(p.group_name, true, &g);
+                else {
+                        _cleanup_(json_variant_unrefp) JsonVariant *last = NULL;
+
+                        setgrent();
+
+                        for (;;) {
+                                _cleanup_(group_record_unrefp) GroupRecord *z = NULL;
+                                _cleanup_free_ char *sbuf = NULL;
+                                struct group *grp;
+                                struct sgrp sgrp;
+
+                                errno = 0;
+                                grp = getgrent();
+                                if (!grp) {
+                                        if (errno != 0)
+                                                log_debug_errno(errno, "Failure while iterating through NSS group database, ignoring: %m");
+
+                                        break;
+                                }
+
+                                r = nss_sgrp_for_group(grp, &sgrp, &sbuf);
+                                if (r < 0)
+                                        log_debug_errno(r, "Failed to acquire shadow entry for group %s, ignoring: %m", grp->gr_name);
+
+                                r = nss_group_to_group_record(grp, r >= 0 ? &sgrp : NULL, &z);
+                                if (r < 0) {
+                                        endgrent();
+                                        return r;
+                                }
+
+                                if (last) {
+                                        r = varlink_notify(link, last);
+                                        if (r < 0) {
+                                                endgrent();
+                                                return r;
+                                        }
+
+                                        last = json_variant_unref(last);
+                                }
+
+                                r = build_group_json(link, z, &last);
+                                if (r < 0) {
+                                        endgrent();
+                                        return r;
+                                }
+                        }
+
+                        endgrent();
+
+                        if (!last)
+                                return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+
+                        return varlink_reply(link, last);
+                }
+
+        } else if (streq_ptr(p.service, "io.systemd.Multiplexer")) {
+
+                if (gid_is_valid(p.gid))
+                        r = groupdb_by_gid(p.gid, USERDB_AVOID_MULTIPLEXER, &g);
+                else if (p.group_name)
+                        r = groupdb_by_name(p.group_name, USERDB_AVOID_MULTIPLEXER, &g);
+                else {
+                        _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+                        _cleanup_(json_variant_unrefp) JsonVariant *last = NULL;
+
+                        r = groupdb_all(USERDB_AVOID_MULTIPLEXER, &iterator);
+                        if (r < 0)
+                                return r;
+
+                        for (;;) {
+                                _cleanup_(group_record_unrefp) GroupRecord *z = NULL;
+
+                                r = groupdb_iterator_get(iterator, &z);
+                                if (r == -ESRCH)
+                                        break;
+                                if (r < 0)
+                                        return r;
+
+                                if (last) {
+                                        r = varlink_notify(link, last);
+                                        if (r < 0)
+                                                return r;
+
+                                        last = json_variant_unref(last);
+                                }
+
+                                r = build_group_json(link, z, &last);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        if (!last)
+                                return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+
+                        return varlink_reply(link, last);
+                }
+        } else
+                return varlink_error(link, "io.systemd.UserDatabase.BadService", NULL);
+        if (r == -ESRCH)
+                return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+        if (r < 0) {
+                log_debug_errno(r, "Group lookup failed abnormally: %m");
+                return varlink_error(link, "io.systemd.UserDatabase.ServiceNotAvailable", NULL);
+        }
+
+        if ((uid_is_valid(p.gid) && g->gid != p.gid) ||
+            (p.group_name && !streq(g->group_name, p.group_name)))
+                return varlink_error(link, "io.systemd.UserDatabase.ConflictingRecordFound", NULL);
+
+        r = build_group_json(link, g, &v);
+        if (r < 0)
+                return r;
+
+        return varlink_reply(link, v);
+}
+
+static int vl_method_get_memberships(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
+        static const JsonDispatch dispatch_table[] = {
+                { "userName",  JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, user_name), 0 },
+                { "groupName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, group_name), 0 },
+                { "service",   JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, service),   0 },
+                {}
+        };
+
+        LookupParameters p = {};
+        int r;
+
+        assert(parameters);
+
+        r = json_dispatch(parameters, dispatch_table, NULL, 0, &p);
+        if (r < 0)
+                return r;
+
+        if (streq_ptr(p.service, "io.systemd.NameServiceSwitch")) {
+
+                if (p.group_name) {
+                        _cleanup_(group_record_unrefp) GroupRecord *g = NULL;
+                        const char *last = NULL;
+                        char **i;
+
+                        r = nss_group_record_by_name(p.group_name, true, &g);
+                        if (r == -ESRCH)
+                                return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+                        if (r < 0)
+                                return r;
+
+                        STRV_FOREACH(i, g->members) {
+
+                                if (p.user_name && !streq_ptr(p.user_name, *i))
+                                        continue;
+
+                                if (last) {
+                                        r = varlink_notifyb(link, JSON_BUILD_OBJECT(
+                                                                            JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(last)),
+                                                                            JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(g->group_name))));
+                                        if (r < 0)
+                                                return r;
+                                }
+
+                                last = *i;
+                        }
+
+                        if (!last)
+                                return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+
+                        return varlink_replyb(link, JSON_BUILD_OBJECT(
+                                                              JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(last)),
+                                                              JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(g->group_name))));
+                } else {
+                        _cleanup_free_ char *last_user_name = NULL, *last_group_name = NULL;
+
+                        setgrent();
+
+                        for (;;) {
+                                struct group *grp;
+                                const char* two[2], **users, **i;
+
+                                errno = 0;
+                                grp = getgrent();
+                                if (!grp) {
+                                        if (errno != 0)
+                                                log_debug_errno(errno, "Failure while iterating through NSS group database, ignoring: %m");
+
+                                        break;
+                                }
+
+                                if (p.user_name) {
+                                        if (!strv_contains(grp->gr_mem, p.user_name))
+                                                continue;
+
+                                        two[0] = p.user_name;
+                                        two[1] = NULL;
+
+                                        users = two;
+                                } else
+                                        users = (const char**) grp->gr_mem;
+
+                                STRV_FOREACH(i, users) {
+
+                                        if (last_user_name) {
+                                                assert(last_group_name);
+
+                                                r = varlink_notifyb(link, JSON_BUILD_OBJECT(
+                                                                                    JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(last_user_name)),
+                                                                                    JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(last_group_name))));
+                                                if (r < 0) {
+                                                        endgrent();
+                                                        return r;
+                                                }
+
+                                                free(last_user_name);
+                                                free(last_group_name);
+                                        }
+
+                                        last_user_name = strdup(*i);
+                                        last_group_name = strdup(grp->gr_name);
+                                        if (!last_user_name || !last_group_name) {
+                                                endgrent();
+                                                return -ENOMEM;
+                                        }
+                                }
+                        }
+
+                        endgrent();
+
+                        if (!last_user_name) {
+                                assert(!last_group_name);
+                                return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+                        }
+
+                        assert(last_group_name);
+
+                        return varlink_replyb(link, JSON_BUILD_OBJECT(
+                                                              JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(last_user_name)),
+                                                              JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(last_group_name))));
+                }
+
+        } else if (streq_ptr(p.service, "io.systemd.Multiplexer")) {
+
+                _cleanup_free_ char *last_user_name = NULL, *last_group_name = NULL;
+                _cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
+
+                if (p.group_name)
+                        r = membershipdb_by_group(p.group_name, USERDB_AVOID_MULTIPLEXER, &iterator);
+                else if (p.user_name)
+                        r = membershipdb_by_user(p.user_name, USERDB_AVOID_MULTIPLEXER, &iterator);
+                else
+                        r = membershipdb_all(USERDB_AVOID_MULTIPLEXER, &iterator);
+                if (r < 0)
+                        return r;
+
+                for (;;) {
+                        _cleanup_free_ char *user_name = NULL, *group_name = NULL;
+
+                        r = membershipdb_iterator_get(iterator, &user_name, &group_name);
+                        if (r == -ESRCH)
+                                break;
+                        if (r < 0)
+                                return r;
+
+                        /* If both group + user are specified do a-posteriori filtering */
+                        if (p.group_name && p.user_name && !streq(group_name, p.group_name))
+                                continue;
+
+                        if (last_user_name) {
+                                assert(last_group_name);
+
+                                r = varlink_notifyb(link, JSON_BUILD_OBJECT(
+                                                                    JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(last_user_name)),
+                                                                    JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(last_group_name))));
+                                if (r < 0)
+                                        return r;
+
+                                free(last_user_name);
+                                free(last_group_name);
+                        }
+
+                        last_user_name = TAKE_PTR(user_name);
+                        last_group_name = TAKE_PTR(group_name);
+                }
+
+                if (!last_user_name) {
+                        assert(!last_group_name);
+                        return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
+                }
+
+                assert(last_group_name);
+
+                return varlink_replyb(link, JSON_BUILD_OBJECT(
+                                                      JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(last_user_name)),
+                                                      JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(last_group_name))));
+        }
+
+        return varlink_error(link, "io.systemd.UserDatabase.BadService", NULL);
+}
+
+static int process_connection(VarlinkServer *server, int fd) {
+        _cleanup_(varlink_close_unrefp) Varlink *vl = NULL;
+        int r;
+
+        r = varlink_server_add_connection(server, fd, &vl);
+        if (r < 0) {
+                fd = safe_close(fd);
+                return log_error_errno(r, "Failed to add connection: %m");
+        }
+
+        vl = varlink_ref(vl);
+
+        for (;;) {
+                r = varlink_process(vl);
+                if (r == -ENOTCONN) {
+                        log_debug("Connection terminated.");
+                        break;
+                }
+                if (r < 0)
+                        return log_error_errno(r, "Failed to process connection: %m");
+                if (r > 0)
+                        continue;
+
+                r = varlink_wait(vl, CONNECTION_IDLE_USEC);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to wait for connection events: %m");
+                if (r == 0)
+                        break;
+        }
+
+        return 0;
+}
+
+static int run(int argc, char *argv[]) {
+        usec_t start_time, listen_idle_usec, last_busy_usec = USEC_INFINITY;
+        _cleanup_(varlink_server_unrefp) VarlinkServer *server = NULL;
+        unsigned n_iterations = 0;
+        int m, listen_fd, r;
+
+        log_setup_service();
+
+        m = sd_listen_fds(false);
+        if (m < 0)
+                return log_error_errno(m, "Failed to determine number of listening fds: %m");
+        if (m == 0)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "No socket to listen on received.");
+        if (m > 1)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Worker can only listen on a single socket at a time.");
+
+        listen_fd = SD_LISTEN_FDS_START;
+
+        r = fd_nonblock(listen_fd, false);
+        if (r < 0)
+                return log_error_errno(r, "Failed to turn off non-blocking mode for listening socket: %m");
+
+        r = varlink_server_new(&server, 0);
+        if (r < 0)
+                return log_error_errno(r, "Failed to allocate server: %m");
+
+        r = varlink_server_bind_method_many(
+                        server,
+                        "io.systemd.UserDatabase.GetUserRecord",  vl_method_get_user_record,
+                        "io.systemd.UserDatabase.GetGroupRecord", vl_method_get_group_record,
+                        "io.systemd.UserDatabase.GetMemberships", vl_method_get_memberships);
+        if (r < 0)
+                return log_error_errno(r, "Failed to bind methods: %m");
+
+        r = getenv_bool("USERDB_FIXED_WORKER");
+        if (r < 0)
+                return log_error_errno(r, "Failed to parse USERDB_FIXED_WORKER: %m");
+        listen_idle_usec = r ? USEC_INFINITY : LISTEN_IDLE_USEC;
+
+        r = userdb_block_nss_systemd(true);
+        if (r < 0)
+                return log_error_errno(r, "Failed to disable userdb NSS compatibility: %m");
+
+        start_time = now(CLOCK_MONOTONIC);
+
+        for (;;) {
+                _cleanup_close_ int fd = -1;
+                usec_t n;
+
+                /* Exit the worker in regular intervals, to flush out all memory use */
+                if (n_iterations++ > ITERATIONS_MAX) {
+                        log_debug("Exiting worker, processed %u iterations, that's enough.", n_iterations);
+                        break;
+                }
+
+                n = now(CLOCK_MONOTONIC);
+                if (n >= usec_add(start_time, RUNTIME_MAX_USEC)) {
+                        char buf[FORMAT_TIMESPAN_MAX];
+                        log_debug("Exiting worker, ran for %s, that's enough.",
+                                  format_timespan(buf, sizeof(buf), usec_sub_unsigned(n, start_time), 0));
+                        break;
+                }
+
+                if (last_busy_usec == USEC_INFINITY)
+                        last_busy_usec = n;
+                else if (listen_idle_usec != USEC_INFINITY && n >= usec_add(last_busy_usec, listen_idle_usec)) {
+                        char buf[FORMAT_TIMESPAN_MAX];
+                        log_debug("Exiting worker, been idle for %s.",
+                                  format_timespan(buf, sizeof(buf), usec_sub_unsigned(n, last_busy_usec), 0));
+                        break;
+                }
+
+                (void) rename_process("systemd-userwork: waiting...");
+
+                fd = accept4(listen_fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
+                if (fd < 0)
+                        fd = -errno;
+
+                (void) rename_process("systemd-userwork: processing...");
+
+                if (fd == -EAGAIN)
+                        continue; /* The listening socket has SO_RECVTIMEO set, hence a timeout is expected
+                                   * after a while, let's check if it's time to exit though. */
+                if (fd == -EINTR)
+                        continue; /* Might be that somebody attached via strace, let's just continue in that
+                                   * case */
+                if (fd < 0)
+                        return log_error_errno(fd, "Failed to accept() from listening socket: %m");
+
+                if (now(CLOCK_MONOTONIC) <= usec_add(n, PRESSURE_SLEEP_TIME_USEC)) {
+                        /* We only slept a very short time? If so, let's see if there are more sockets
+                         * pending, and if so, let's ask our parent for more workers */
+
+                        r = fd_wait_for_event(listen_fd, POLLIN, 0);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to test for POLLIN on listening socket: %m");
+
+                        if (FLAGS_SET(r, POLLIN)) {
+                                pid_t parent;
+
+                                parent = getppid();
+                                if (parent <= 1)
+                                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Parent already died?");
+
+                                if (kill(parent, SIGUSR2) < 0)
+                                        return log_error_errno(errno, "Failed to kill our own parent.");
+                        }
+                }
+
+                (void) process_connection(server, TAKE_FD(fd));
+                last_busy_usec = USEC_INFINITY;
+        }
+
+        return 0;
+}
+
+DEFINE_MAIN_FUNCTION(run);