Merge pull request #3818 from poettering/exit-status-env

beef up /var/tmp and /tmp handling; set $SERVICE_RESULT/$EXIT_CODE/$EXIT_STATUS on ExecStop= and make sure root/nobody are always resolvable

24 files changed, 417 insertions, 197 deletions

diff --git a/TODO b/TODO
index bb36522bf9..723292cde0 100644
--- a/TODO
+++ b/TODO
@@ -35,27 +35,17 @@ Features:
 
 * RemoveIPC= in unit files for removing POSIX/SysV IPC objects
 
-* Set SERVICE_RESULT= as env var while running ExecStop=
-
 * Introduce ProtectSystem=strict for making the entire OS hierarchy read-only
   except for a select few
 
 * nspawn: start UID allocation loop from hash of container name
 
-* in the DynamicUser=1 nss module, also map "nobody" and "root" statically
-
-* pid1: log about all processes we kill with with SIGKILL or in abandoned scopes, as this should normally not happen
-
 * nspawn: support that /proc, /sys/, /dev are pre-mounted
 
-* nspawn: mount esp, so that bootctl can work
-
 * define gpt header bits to select volatility mode
 
 * nspawn: mount loopback filesystems with "discard"
 
-* Make TasksMax= take percentages, taken relative to the pids_max sysctl and pids.max cgroup limit
-
 * ProtectKernelLogs= (drops CAP_SYSLOG, add seccomp for syslog() syscall, and DeviceAllow to /dev/kmsg) in service files
 
 * ProtectClock= (drops CAP_SYS_TIMES, adds seecomp filters for settimeofday, adjtimex), sets DeviceAllow o /dev/rtc
diff --git a/configure.ac b/configure.ac
index a86deca471..4d1c96606f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -556,12 +556,30 @@ AC_SUBST(CERTIFICATEROOT)
 
 AC_ARG_WITH([support-url],
         AS_HELP_STRING([--with-support-url=URL],
-                [Specify the supoport URL to show in catalog entries included in systemd]),
+                [Specify the support URL to show in catalog entries included in systemd]),
         [SUPPORT_URL="$withval"],
         [SUPPORT_URL=http://lists.freedesktop.org/mailman/listinfo/systemd-devel])
 
 AC_SUBST(SUPPORT_URL)
 
+AC_ARG_WITH([nobody-user],
+        AS_HELP_STRING([--with-nobody-user=NAME],
+                [Specify the name of the nobody user (the one with UID 65534)]),
+        [NOBODY_USER_NAME="$withval"],
+        [NOBODY_USER_NAME=nobody])
+
+AC_SUBST(NOBODY_USER_NAME)
+AC_DEFINE_UNQUOTED(NOBODY_USER_NAME, ["$NOBODY_USER_NAME"], [The name of the nobody user (the one with UID 65534)])
+
+AC_ARG_WITH([nobody-group],
+        AS_HELP_STRING([--with-nobody-group=NAME],
+                [Specify the name of the nobody group (the one with GID 65534)]),
+        [NOBODY_GROUP_NAME="$withval"],
+        [NOBODY_GROUP_NAME=nobody])
+
+AC_SUBST(NOBODY_GROUP_NAME)
+AC_DEFINE_UNQUOTED(NOBODY_GROUP_NAME, ["$NOBODY_GROUP_NAME"], [The name of the nobody group (the one with GID 65534)])
+
 # ------------------------------------------------------------------------------
 have_xz=no
 AC_ARG_ENABLE(xz, AS_HELP_STRING([--disable-xz], [Disable optional XZ support]))
@@ -1677,6 +1695,8 @@ AC_MSG_RESULT([
         Maximum System GID:                ${SYSTEM_GID_MAX}
         Certificate root:                  ${CERTIFICATEROOT}
         Support URL:                       ${SUPPORT_URL}
+        Nobody User Name:                  ${NOBODY_USER_NAME}
+        Nobody Group Name:                 ${NOBODY_GROUP_NAME}
 
         CFLAGS:   ${OUR_CFLAGS} ${CFLAGS}
         CPPFLAGS: ${OUR_CPPFLAGS} ${CPPFLAGS}
diff --git a/man/nss-systemd.xml b/man/nss-systemd.xml
index 4228372e51..56d26e7d1f 100644
--- a/man/nss-systemd.xml
+++ b/man/nss-systemd.xml
@@ -61,6 +61,10 @@
     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details on
     this option.</para>
 
+    <para>This module also ensures that the root and nobody users and groups (i.e. the users/groups with the UIDs/GIDs
+    0 and 65534) remain resolvable at all times, even if they aren't listed in <filename>/etc/passwd</filename> or
+    <filename>/etc/group</filename>, or if these files are missing.</para>
+
     <para>To activate the NSS module, add <literal>systemd</literal> to the lines starting with
     <literal>passwd:</literal> and <literal>group:</literal> in <filename>/etc/nsswitch.conf</filename>.</para>
 
diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index 58ba582911..0fc658f180 100644
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -1602,6 +1602,43 @@
         functions) if their standard output or standard error output is connected to the journal anyway, thus enabling
         delivery of structured metadata along with logged messages.</para></listitem>
       </varlistentry>
+
+      <varlistentry>
+        <term><varname>$SERVICE_RESULT</varname></term>
+
+        <listitem><para>Only defined for the service unit type, this environment variable is passed to all
+        <varname>ExecStop=</varname> and <varname>ExecStopPost=</varname> processes, and encodes the service
+        "result". Currently, the following values are defined: <literal>timeout</literal> (in case of an operation
+        timeout), <literal>exit-code</literal> (if a service process exited with a non-zero exit code; see
+        <varname>$EXIT_STATUS</varname> below for the actual exit status returned), <literal>signal</literal> (if a
+        service process was terminated abnormally by a signal; see <varname>$EXIT_STATUS</varname> below for the actual
+        signal used for the termination), <literal>core-dump</literal> (if a service process terminated abnormally and
+        dumped core), <literal>watchdog</literal> (if the watchdog keep-alive ping was enabled for the service but it
+        missed the deadline), or <literal>resources</literal> (a catch-all condition in case a system operation
+        failed).</para>
+
+        <para>This environment variable is useful to monitor failure or successful termination of a service. Even
+        though this variable is available in both <varname>ExecStop=</varname> and <varname>ExecStopPost=</varname>, it
+        is usually a better choice to place monitoring tools in the latter, as the former is only invoked for services
+        that managed to start up correctly, and the latter covers both services that failed during their start-up and
+        those which failed during their runtime.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><varname>$EXIT_CODE</varname></term>
+        <term><varname>$EXIT_STATUS</varname></term>
+
+        <listitem><para>Only defined for the service unit type, these environment variables are passed to all
+        <varname>ExecStop=</varname>, <varname>ExecStopPost=</varname> processes and contain exit status/code
+        information of the main process of the service. For the precise definition of the exit code and status, see
+        <citerefentry><refentrytitle>wait</refentrytitle><manvolnum>2</manvolnum></citerefentry>. <varname>$EXIT_CODE</varname>
+        is one of <literal>exited</literal>, <literal>killed</literal>,
+        <literal>dumped</literal>. <varname>$EXIT_STATUS</varname> contains the numeric exit code formatted as string
+        if <varname>$EXIT_CODE</varname> is <literal>exited</literal>, and the signal name in all other cases. Note
+        that these environment variables are only set if the service manager succeeded to start and identify the main
+        process of the service.</para></listitem>
+      </varlistentry>
+
     </variablelist>
 
     <para>Additional variables may be configured by the following
diff --git a/man/systemd.service.xml b/man/systemd.service.xml
index 875d368fcf..e82edbe93e 100644
--- a/man/systemd.service.xml
+++ b/man/systemd.service.xml
@@ -429,7 +429,13 @@
         service failed to start up correctly. Commands configured with this setting need to be able to operate even if
         the service failed starting up half-way and left incompletely initialized data around. As the service's
         processes have been terminated already when the commands specified with this setting are executed they should
-        not attempt to communicate with them.</para></listitem>
+        not attempt to communicate with them.</para>
+
+        <para>Note that all commands that are configured with this setting are invoked with the result code of the
+        service, as well as the main process' exit code and status, set in the <varname>$SERVICE_RESULT</varname>,
+        <varname>$EXIT_CODE</varname> and <varname>$EXIT_STATUS</varname> environment variables, see
+        <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
+        details.</para></listitem>
       </varlistentry>
 
       <varlistentry>
diff --git a/src/basic/fileio.c b/src/basic/fileio.c
index 588eacd77c..d642f3daea 100644
--- a/src/basic/fileio.c
+++ b/src/basic/fileio.c
@@ -1168,8 +1168,8 @@ int tempfn_random_child(const char *p, const char *extra, char **ret) {
         char *t, *x;
         uint64_t u;
         unsigned i;
+        int r;
 
-        assert(p);
         assert(ret);
 
         /* Turns this:
@@ -1178,6 +1178,12 @@ int tempfn_random_child(const char *p, const char *extra, char **ret) {
          *         /foo/bar/waldo/.#<extra>3c2b6219aa75d7d0
          */
 
+        if (!p) {
+                r = tmp_dir(&p);
+                if (r < 0)
+                        return r;
+        }
+
         if (!extra)
                 extra = "";
 
@@ -1264,10 +1270,13 @@ int fputs_with_space(FILE *f, const char *s, const char *separator, bool *space)
 
 int open_tmpfile_unlinkable(const char *directory, int flags) {
         char *p;
-        int fd;
+        int fd, r;
 
-        if (!directory)
-                directory = "/tmp";
+        if (!directory) {
+                r = tmp_dir(&directory);
+                if (r < 0)
+                        return r;
+        }
 
         /* Returns an unlinked temporary file that cannot be linked into the file system anymore */
 
diff --git a/src/basic/fs-util.c b/src/basic/fs-util.c
index f0c6f3265e..ce87257bc1 100644
--- a/src/basic/fs-util.c
+++ b/src/basic/fs-util.c
@@ -496,34 +496,94 @@ int get_files_in_directory(const char *path, char ***list) {
         return n;
 }
 
-int var_tmp(char **ret) {
-        const char *tmp_dir = NULL;
-        const char *env_tmp_dir = NULL;
-        char *c = NULL;
-        int r;
+static int getenv_tmp_dir(const char **ret_path) {
+        const char *n;
+        int r, ret = 0;
 
-        assert(ret);
+        assert(ret_path);
 
-        env_tmp_dir = getenv("TMPDIR");
-        if (env_tmp_dir != NULL) {
-                r = is_dir(env_tmp_dir, true);
-                if (r < 0 && r != -ENOENT)
-                        return r;
-                if (r > 0)
-                        tmp_dir = env_tmp_dir;
+        /* We use the same order of environment variables python uses in tempfile.gettempdir():
+         * https://docs.python.org/3/library/tempfile.html#tempfile.gettempdir */
+        FOREACH_STRING(n, "TMPDIR", "TEMP", "TMP") {
+                const char *e;
+
+                e = secure_getenv(n);
+                if (!e)
+                        continue;
+                if (!path_is_absolute(e)) {
+                        r = -ENOTDIR;
+                        goto next;
+                }
+                if (!path_is_safe(e)) {
+                        r = -EPERM;
+                        goto next;
+                }
+
+                r = is_dir(e, true);
+                if (r < 0)
+                        goto next;
+                if (r == 0) {
+                        r = -ENOTDIR;
+                        goto next;
+                }
+
+                *ret_path = e;
+                return 1;
+
+        next:
+                /* Remember first error, to make this more debuggable */
+                if (ret >= 0)
+                        ret = r;
         }
 
-        if (!tmp_dir)
-                tmp_dir = "/var/tmp";
+        if (ret < 0)
+                return ret;
 
-        c = strdup(tmp_dir);
-        if (!c)
-                return -ENOMEM;
-        *ret = c;
+        *ret_path = NULL;
+        return ret;
+}
 
+static int tmp_dir_internal(const char *def, const char **ret) {
+        const char *e;
+        int r, k;
+
+        assert(def);
+        assert(ret);
+
+        r = getenv_tmp_dir(&e);
+        if (r > 0) {
+                *ret = e;
+                return 0;
+        }
+
+        k = is_dir(def, true);
+        if (k == 0)
+                k = -ENOTDIR;
+        if (k < 0)
+                return r < 0 ? r : k;
+
+        *ret = def;
         return 0;
 }
 
+int var_tmp_dir(const char **ret) {
+
+        /* Returns the location for "larger" temporary files, that is backed by physical storage if available, and thus
+         * even might survive a boot: /var/tmp. If $TMPDIR (or related environment variables) are set, its value is
+         * returned preferably however. Note that both this function and tmp_dir() below are affected by $TMPDIR,
+         * making it a variable that overrides all temporary file storage locations. */
+
+        return tmp_dir_internal("/var/tmp", ret);
+}
+
+int tmp_dir(const char **ret) {
+
+        /* Similar to var_tmp_dir() above, but returns the location for "smaller" temporary files, which is usually
+         * backed by an in-memory file system: /tmp. */
+
+        return tmp_dir_internal("/tmp", ret);
+}
+
 int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
         char path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
         int r;
diff --git a/src/basic/fs-util.h b/src/basic/fs-util.h
index 075e5942b1..2c3b9a1c74 100644
--- a/src/basic/fs-util.h
+++ b/src/basic/fs-util.h
@@ -61,7 +61,8 @@ int mkfifo_atomic(const char *path, mode_t mode);
 
 int get_files_in_directory(const char *path, char ***list);
 
-int var_tmp(char **ret);
+int tmp_dir(const char **ret);
+int var_tmp_dir(const char **ret);
 
 #define INOTIFY_EVENT_MAX (sizeof(struct inotify_event) + NAME_MAX + 1)
 
diff --git a/src/core/automount.c b/src/core/automount.c
index 20a73c76f9..00295cf769 100644
--- a/src/core/automount.c
+++ b/src/core/automount.c
@@ -301,7 +301,7 @@ static void automount_dump(Unit *u, FILE *f, const char *prefix) {
 static void automount_enter_dead(Automount *a, AutomountResult f) {
         assert(a);
 
-        if (f != AUTOMOUNT_SUCCESS)
+        if (a->result == AUTOMOUNT_SUCCESS)
                 a->result = f;
 
         automount_set_state(a, a->result != AUTOMOUNT_SUCCESS ? AUTOMOUNT_FAILED : AUTOMOUNT_DEAD);
diff --git a/src/core/busname.c b/src/core/busname.c
index 730be2ee14..7952cd31aa 100644
--- a/src/core/busname.c
+++ b/src/core/busname.c
@@ -442,7 +442,7 @@ fail:
 static void busname_enter_dead(BusName *n, BusNameResult f) {
         assert(n);
 
-        if (f != BUSNAME_SUCCESS)
+        if (n->result == BUSNAME_SUCCESS)
                 n->result = f;
 
         busname_set_state(n, n->result != BUSNAME_SUCCESS ? BUSNAME_FAILED : BUSNAME_DEAD);
@@ -454,7 +454,7 @@ static void busname_enter_signal(BusName *n, BusNameState state, BusNameResult f
 
         assert(n);
 
-        if (f != BUSNAME_SUCCESS)
+        if (n->result == BUSNAME_SUCCESS)
                 n->result = f;
 
         kill_context_init(&kill_context);
@@ -882,7 +882,7 @@ static void busname_sigchld_event(Unit *u, pid_t pid, int code, int status) {
         log_unit_full(u, f == BUSNAME_SUCCESS ? LOG_DEBUG : LOG_NOTICE, 0,
                       "Control process exited, code=%s status=%i", sigchld_code_to_string(code), status);
 
-        if (f != BUSNAME_SUCCESS)
+        if (n->result == BUSNAME_SUCCESS)
                 n->result = f;
 
         switch (n->state) {
diff --git a/src/core/execute.c b/src/core/execute.c
index 77a75245cb..7aafb1b058 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -427,7 +427,7 @@ static int setup_input(
                 return STDIN_FILENO;
         }
 
-        i = fixup_input(context->std_input, socket_fd, params->apply_tty_stdin);
+        i = fixup_input(context->std_input, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
 
         switch (i) {
 
@@ -502,7 +502,7 @@ static int setup_output(
                 return STDERR_FILENO;
         }
 
-        i = fixup_input(context->std_input, socket_fd, params->apply_tty_stdin);
+        i = fixup_input(context->std_input, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
         o = fixup_output(context->std_output, socket_fd);
 
         if (fileno == STDERR_FILENO) {
@@ -1425,7 +1425,7 @@ static int build_environment(
                 our_env[n_env++] = x;
         }
 
-        if (p->watchdog_usec > 0) {
+        if ((p->flags & EXEC_SET_WATCHDOG) && p->watchdog_usec > 0) {
                 if (asprintf(&x, "WATCHDOG_PID="PID_FMT, getpid()) < 0)
                         return -ENOMEM;
                 our_env[n_env++] = x;
@@ -1675,7 +1675,7 @@ static int exec_child(
 
         exec_context_tty_reset(context, params);
 
-        if (params->confirm_spawn) {
+        if (params->flags & EXEC_CONFIRM_SPAWN) {
                 char response;
 
                 r = ask_for_confirmation(&response, argv);
@@ -1940,7 +1940,7 @@ static int exec_child(
 
         umask(context->umask);
 
-        if (params->apply_permissions && !command->privileged) {
+        if ((params->flags & EXEC_APPLY_PERMISSIONS) && !command->privileged) {
                 r = enforce_groups(context, username, gid);
                 if (r < 0) {
                         *exit_status = EXIT_GROUP;
@@ -2010,7 +2010,7 @@ static int exec_child(
                 }
 
                 r = setup_namespace(
-                                params->apply_chroot ? context->root_directory : NULL,
+                                (params->flags & EXEC_APPLY_CHROOT) ? context->root_directory : NULL,
                                 context->read_write_paths,
                                 context->read_only_paths,
                                 context->inaccessible_paths,
@@ -2041,7 +2041,7 @@ static int exec_child(
         else
                 wd = "/";
 
-        if (params->apply_chroot) {
+        if (params->flags & EXEC_APPLY_CHROOT) {
                 if (!needs_mount_namespace && context->root_directory)
                         if (chroot(context->root_directory) < 0) {
                                 *exit_status = EXIT_CHROOT;
@@ -2065,7 +2065,12 @@ static int exec_child(
         }
 
 #ifdef HAVE_SELINUX
-        if (params->apply_permissions && mac_selinux_use() && params->selinux_context_net && socket_fd >= 0 && !command->privileged) {
+        if ((params->flags & EXEC_APPLY_PERMISSIONS) &&
+            mac_selinux_use() &&
+            params->selinux_context_net &&
+            socket_fd >= 0 &&
+            !command->privileged) {
+
                 r = mac_selinux_get_child_mls_label(socket_fd, command->path, context->selinux_context, &mac_selinux_context_net);
                 if (r < 0) {
                         *exit_status = EXIT_SELINUX_CONTEXT;
@@ -2090,7 +2095,7 @@ static int exec_child(
                 return r;
         }
 
-        if (params->apply_permissions && !command->privileged) {
+        if ((params->flags & EXEC_APPLY_PERMISSIONS) && !command->privileged) {
 
                 bool use_address_families = context->address_families_whitelist ||
                         !set_isempty(context->address_families);
@@ -2964,12 +2969,12 @@ void exec_status_dump(ExecStatus *s, FILE *f, const char *prefix) {
                 "%sPID: "PID_FMT"\n",
                 prefix, s->pid);
 
-        if (s->start_timestamp.realtime > 0)
+        if (dual_timestamp_is_set(&s->start_timestamp))
                 fprintf(f,
                         "%sStart Timestamp: %s\n",
                         prefix, format_timestamp(buf, sizeof(buf), s->start_timestamp.realtime));
 
-        if (s->exit_timestamp.realtime > 0)
+        if (dual_timestamp_is_set(&s->exit_timestamp))
                 fprintf(f,
                         "%sExit Timestamp: %s\n"
                         "%sExit Code: %s\n"
diff --git a/src/core/execute.h b/src/core/execute.h
index 48cc18fbb3..2d05ca39aa 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -208,6 +208,19 @@ struct ExecContext {
         bool no_new_privileges_set:1;
 };
 
+typedef enum ExecFlags {
+        EXEC_CONFIRM_SPAWN     = 1U << 0,
+        EXEC_APPLY_PERMISSIONS = 1U << 1,
+        EXEC_APPLY_CHROOT      = 1U << 2,
+        EXEC_APPLY_TTY_STDIN   = 1U << 3,
+
+        /* The following are not used by execute.c, but by consumers internally */
+        EXEC_PASS_FDS          = 1U << 4,
+        EXEC_IS_CONTROL        = 1U << 5,
+        EXEC_SETENV_RESULT     = 1U << 6,
+        EXEC_SET_WATCHDOG      = 1U << 7,
+} ExecFlags;
+
 struct ExecParameters {
         char **argv;
         char **environment;
@@ -216,11 +229,7 @@ struct ExecParameters {
         char **fd_names;
         unsigned n_fds;
 
-        bool apply_permissions:1;
-        bool apply_chroot:1;
-        bool apply_tty_stdin:1;
-
-        bool confirm_spawn:1;
+        ExecFlags flags;
         bool selinux_context_net:1;
 
         bool cgroup_delegate:1;
diff --git a/src/core/mount.c b/src/core/mount.c
index afb20af9e2..f3ccf6d48a 100644
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -701,12 +701,10 @@ static int mount_spawn(Mount *m, ExecCommand *c, pid_t *_pid) {
         pid_t pid;
         int r;
         ExecParameters exec_params = {
-                .apply_permissions = true,
-                .apply_chroot      = true,
-                .apply_tty_stdin   = true,
-                .stdin_fd          = -1,
-                .stdout_fd         = -1,
-                .stderr_fd         = -1,
+                .flags      = EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_APPLY_TTY_STDIN,
+                .stdin_fd   = -1,
+                .stdout_fd  = -1,
+                .stderr_fd  = -1,
         };
 
         assert(m);
@@ -732,7 +730,7 @@ static int mount_spawn(Mount *m, ExecCommand *c, pid_t *_pid) {
                 return r;
 
         exec_params.environment = UNIT(m)->manager->environment;
-        exec_params.confirm_spawn = UNIT(m)->manager->confirm_spawn;
+        exec_params.flags |= UNIT(m)->manager->confirm_spawn ? EXEC_CONFIRM_SPAWN : 0;
         exec_params.cgroup_supported = UNIT(m)->manager->cgroup_supported;
         exec_params.cgroup_path = UNIT(m)->cgroup_path;
         exec_params.cgroup_delegate = m->cgroup_context.delegate;
@@ -761,7 +759,7 @@ static int mount_spawn(Mount *m, ExecCommand *c, pid_t *_pid) {
 static void mount_enter_dead(Mount *m, MountResult f) {
         assert(m);
 
-        if (f != MOUNT_SUCCESS)
+        if (m->result == MOUNT_SUCCESS)
                 m->result = f;
 
         mount_set_state(m, m->result != MOUNT_SUCCESS ? MOUNT_FAILED : MOUNT_DEAD);
@@ -777,7 +775,7 @@ static void mount_enter_dead(Mount *m, MountResult f) {
 static void mount_enter_mounted(Mount *m, MountResult f) {
         assert(m);
 
-        if (f != MOUNT_SUCCESS)
+        if (m->result == MOUNT_SUCCESS)
                 m->result = f;
 
         mount_set_state(m, MOUNT_MOUNTED);
@@ -788,7 +786,7 @@ static void mount_enter_signal(Mount *m, MountState state, MountResult f) {
 
         assert(m);
 
-        if (f != MOUNT_SUCCESS)
+        if (m->result == MOUNT_SUCCESS)
                 m->result = f;
 
         r = unit_kill_context(
@@ -1160,7 +1158,7 @@ static void mount_sigchld_event(Unit *u, pid_t pid, int code, int status) {
         else
                 assert_not_reached("Unknown code");
 
-        if (f != MOUNT_SUCCESS)
+        if (m->result == MOUNT_SUCCESS)
                 m->result = f;
 
         if (m->control_command) {
diff --git a/src/core/path.c b/src/core/path.c
index 0dd0d375d8..10f9b06974 100644
--- a/src/core/path.c
+++ b/src/core/path.c
@@ -454,7 +454,7 @@ static int path_coldplug(Unit *u) {
 static void path_enter_dead(Path *p, PathResult f) {
         assert(p);
 
-        if (f != PATH_SUCCESS)
+        if (p->result == PATH_SUCCESS)
                 p->result = f;
 
         path_set_state(p, p->result != PATH_SUCCESS ? PATH_FAILED : PATH_DEAD);
diff --git a/src/core/scope.c b/src/core/scope.c
index b45e238974..b278aed3d6 100644
--- a/src/core/scope.c
+++ b/src/core/scope.c
@@ -221,7 +221,7 @@ static void scope_dump(Unit *u, FILE *f, const char *prefix) {
 static void scope_enter_dead(Scope *s, ScopeResult f) {
         assert(s);
 
-        if (f != SCOPE_SUCCESS)
+        if (s->result == SCOPE_SUCCESS)
                 s->result = f;
 
         scope_set_state(s, s->result != SCOPE_SUCCESS ? SCOPE_FAILED : SCOPE_DEAD);
@@ -233,7 +233,7 @@ static void scope_enter_signal(Scope *s, ScopeState state, ScopeResult f) {
 
         assert(s);
 
-        if (f != SCOPE_SUCCESS)
+        if (s->result == SCOPE_SUCCESS)
                 s->result = f;
 
         unit_watch_all_pids(UNIT(s));
diff --git a/src/core/service.c b/src/core/service.c
index 3c9455a5f8..4a37702f52 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -1171,11 +1171,7 @@ static int service_spawn(
                 Service *s,
                 ExecCommand *c,
                 usec_t timeout,
-                bool pass_fds,
-                bool apply_permissions,
-                bool apply_chroot,
-                bool apply_tty_stdin,
-                bool is_control,
+                ExecFlags flags,
                 pid_t *_pid) {
 
         _cleanup_strv_free_ char **argv = NULL, **final_env = NULL, **our_env = NULL, **fd_names = NULL;
@@ -1185,12 +1181,10 @@ static int service_spawn(
         pid_t pid;
 
         ExecParameters exec_params = {
-                .apply_permissions = apply_permissions,
-                .apply_chroot      = apply_chroot,
-                .apply_tty_stdin   = apply_tty_stdin,
-                .stdin_fd          = -1,
-                .stdout_fd         = -1,
-                .stderr_fd         = -1,
+                .flags      = flags,
+                .stdin_fd   = -1,
+                .stdout_fd  = -1,
+                .stderr_fd  = -1,
         };
 
         int r;
@@ -1199,6 +1193,14 @@ static int service_spawn(
         assert(c);
         assert(_pid);
 
+        if (flags & EXEC_IS_CONTROL) {
+                /* If this is a control process, mask the permissions/chroot application if this is requested. */
+                if (s->permissions_start_only)
+                        exec_params.flags &= ~EXEC_APPLY_PERMISSIONS;
+                if (s->root_directory_start_only)
+                        exec_params.flags &= ~EXEC_APPLY_CHROOT;
+        }
+
         (void) unit_realize_cgroup(UNIT(s));
         if (s->reset_cpu_usage) {
                 (void) unit_reset_cpu_usage(UNIT(s));
@@ -1213,7 +1215,7 @@ static int service_spawn(
         if (r < 0)
                 return r;
 
-        if (pass_fds ||
+        if ((flags & EXEC_PASS_FDS) ||
             s->exec_context.std_input == EXEC_INPUT_SOCKET ||
             s->exec_context.std_output == EXEC_OUTPUT_SOCKET ||
             s->exec_context.std_error == EXEC_OUTPUT_SOCKET) {
@@ -1233,11 +1235,11 @@ static int service_spawn(
         if (r < 0)
                 return r;
 
-        our_env = new0(char*, 6);
+        our_env = new0(char*, 9);
         if (!our_env)
                 return -ENOMEM;
 
-        if (is_control ? s->notify_access == NOTIFY_ALL : s->notify_access != NOTIFY_NONE)
+        if ((flags & EXEC_IS_CONTROL) ? s->notify_access == NOTIFY_ALL : s->notify_access != NOTIFY_NONE)
                 if (asprintf(our_env + n_env++, "NOTIFY_SOCKET=%s", UNIT(s)->manager->notify_socket) < 0)
                         return -ENOMEM;
 
@@ -1245,7 +1247,7 @@ static int service_spawn(
                 if (asprintf(our_env + n_env++, "MAINPID="PID_FMT, s->main_pid) < 0)
                         return -ENOMEM;
 
-        if (!MANAGER_IS_SYSTEM(UNIT(s)->manager))
+        if (MANAGER_IS_USER(UNIT(s)->manager))
                 if (asprintf(our_env + n_env++, "MANAGERPID="PID_FMT, getpid()) < 0)
                         return -ENOMEM;
 
@@ -1281,22 +1283,40 @@ static int service_spawn(
                 }
         }
 
+        if (flags & EXEC_SETENV_RESULT) {
+                if (asprintf(our_env + n_env++, "SERVICE_RESULT=%s", service_result_to_string(s->result)) < 0)
+                        return -ENOMEM;
+
+                if (s->main_exec_status.pid > 0 &&
+                    dual_timestamp_is_set(&s->main_exec_status.exit_timestamp)) {
+                        if (asprintf(our_env + n_env++, "EXIT_CODE=%s", sigchld_code_to_string(s->main_exec_status.code)) < 0)
+                                return -ENOMEM;
+
+                        if (s->main_exec_status.code == CLD_EXITED)
+                                r = asprintf(our_env + n_env++, "EXIT_STATUS=%i", s->main_exec_status.status);
+                        else
+                                r = asprintf(our_env + n_env++, "EXIT_STATUS=%s", signal_to_string(s->main_exec_status.status));
+                        if (r < 0)
+                                return -ENOMEM;
+                }
+        }
+
         final_env = strv_env_merge(2, UNIT(s)->manager->environment, our_env, NULL);
         if (!final_env)
                 return -ENOMEM;
 
-        if (is_control && UNIT(s)->cgroup_path) {
+        if ((flags & EXEC_IS_CONTROL) && UNIT(s)->cgroup_path) {
                 path = strjoina(UNIT(s)->cgroup_path, "/control");
                 (void) cg_create(SYSTEMD_CGROUP_CONTROLLER, path);
         } else
                 path = UNIT(s)->cgroup_path;
 
         exec_params.argv = argv;
+        exec_params.environment = final_env;
         exec_params.fds = fds;
         exec_params.fd_names = fd_names;
         exec_params.n_fds = n_fds;
-        exec_params.environment = final_env;
-        exec_params.confirm_spawn = UNIT(s)->manager->confirm_spawn;
+        exec_params.flags |= UNIT(s)->manager->confirm_spawn ? EXEC_CONFIRM_SPAWN : 0;
         exec_params.cgroup_supported = UNIT(s)->manager->cgroup_supported;
         exec_params.cgroup_path = path;
         exec_params.cgroup_delegate = s->cgroup_context.delegate;
@@ -1422,7 +1442,7 @@ static void service_enter_dead(Service *s, ServiceResult f, bool allow_restart)
         int r;
         assert(s);
 
-        if (f != SERVICE_SUCCESS)
+        if (s->result == SERVICE_SUCCESS)
                 s->result = f;
 
         service_set_state(s, s->result != SERVICE_SUCCESS ? SERVICE_FAILED : SERVICE_DEAD);
@@ -1471,7 +1491,7 @@ static void service_enter_stop_post(Service *s, ServiceResult f) {
         int r;
         assert(s);
 
-        if (f != SERVICE_SUCCESS)
+        if (s->result == SERVICE_SUCCESS)
                 s->result = f;
 
         service_unwatch_control_pid(s);
@@ -1484,11 +1504,7 @@ static void service_enter_stop_post(Service *s, ServiceResult f) {
                 r = service_spawn(s,
                                   s->control_command,
                                   s->timeout_stop_usec,
-                                  false,
-                                  !s->permissions_start_only,
-                                  !s->root_directory_start_only,
-                                  true,
-                                  true,
+                                  EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_APPLY_TTY_STDIN|EXEC_IS_CONTROL|EXEC_SETENV_RESULT,
                                   &s->control_pid);
                 if (r < 0)
                         goto fail;
@@ -1528,7 +1544,7 @@ static void service_enter_signal(Service *s, ServiceState state, ServiceResult f
 
         assert(s);
 
-        if (f != SERVICE_SUCCESS)
+        if (s->result == SERVICE_SUCCESS)
                 s->result = f;
 
         unit_watch_all_pids(UNIT(s));
@@ -1586,7 +1602,7 @@ static void service_enter_stop(Service *s, ServiceResult f) {
 
         assert(s);
 
-        if (f != SERVICE_SUCCESS)
+        if (s->result == SERVICE_SUCCESS)
                 s->result = f;
 
         service_unwatch_control_pid(s);
@@ -1599,11 +1615,7 @@ static void service_enter_stop(Service *s, ServiceResult f) {
                 r = service_spawn(s,
                                   s->control_command,
                                   s->timeout_stop_usec,
-                                  false,
-                                  !s->permissions_start_only,
-                                  !s->root_directory_start_only,
-                                  false,
-                                  true,
+                                  EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_IS_CONTROL|EXEC_SETENV_RESULT,
                                   &s->control_pid);
                 if (r < 0)
                         goto fail;
@@ -1642,7 +1654,7 @@ static bool service_good(Service *s) {
 static void service_enter_running(Service *s, ServiceResult f) {
         assert(s);
 
-        if (f != SERVICE_SUCCESS)
+        if (s->result == SERVICE_SUCCESS)
                 s->result = f;
 
         service_unwatch_control_pid(s);
@@ -1680,11 +1692,7 @@ static void service_enter_start_post(Service *s) {
                 r = service_spawn(s,
                                   s->control_command,
                                   s->timeout_start_usec,
-                                  false,
-                                  !s->permissions_start_only,
-                                  !s->root_directory_start_only,
-                                  false,
-                                  true,
+                                  EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_IS_CONTROL,
                                   &s->control_pid);
                 if (r < 0)
                         goto fail;
@@ -1754,11 +1762,7 @@ static void service_enter_start(Service *s) {
         r = service_spawn(s,
                           c,
                           timeout,
-                          true,
-                          true,
-                          true,
-                          true,
-                          false,
+                          EXEC_PASS_FDS|EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_APPLY_TTY_STDIN|EXEC_SET_WATCHDOG,
                           &pid);
         if (r < 0)
                 goto fail;
@@ -1817,11 +1821,7 @@ static void service_enter_start_pre(Service *s) {
                 r = service_spawn(s,
                                   s->control_command,
                                   s->timeout_start_usec,
-                                  false,
-                                  !s->permissions_start_only,
-                                  !s->root_directory_start_only,
-                                  true,
-                                  true,
+                                  EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_IS_CONTROL|EXEC_APPLY_TTY_STDIN,
                                   &s->control_pid);
                 if (r < 0)
                         goto fail;
@@ -1896,11 +1896,7 @@ static void service_enter_reload(Service *s) {
                 r = service_spawn(s,
                                   s->control_command,
                                   s->timeout_start_usec,
-                                  false,
-                                  !s->permissions_start_only,
-                                  !s->root_directory_start_only,
-                                  false,
-                                  true,
+                                  EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_IS_CONTROL,
                                   &s->control_pid);
                 if (r < 0)
                         goto fail;
@@ -1938,12 +1934,9 @@ static void service_run_next_control(Service *s) {
         r = service_spawn(s,
                           s->control_command,
                           timeout,
-                          false,
-                          !s->permissions_start_only,
-                          !s->root_directory_start_only,
-                          s->control_command_id == SERVICE_EXEC_START_PRE ||
-                          s->control_command_id == SERVICE_EXEC_STOP_POST,
-                          true,
+                          EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_IS_CONTROL|
+                          (IN_SET(s->control_command_id, SERVICE_EXEC_START_PRE, SERVICE_EXEC_STOP_POST) ? EXEC_APPLY_TTY_STDIN : 0)|
+                          (IN_SET(s->control_command_id, SERVICE_EXEC_STOP, SERVICE_EXEC_STOP_POST) ? EXEC_SETENV_RESULT : 0),
                           &s->control_pid);
         if (r < 0)
                 goto fail;
@@ -1981,11 +1974,7 @@ static void service_run_next_main(Service *s) {
         r = service_spawn(s,
                           s->main_command,
                           s->timeout_start_usec,
-                          true,
-                          true,
-                          true,
-                          true,
-                          false,
+                          EXEC_PASS_FDS|EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_APPLY_TTY_STDIN|EXEC_SET_WATCHDOG,
                           &pid);
         if (r < 0)
                 goto fail;
@@ -2656,7 +2645,7 @@ static void service_sigchld_event(Unit *u, pid_t pid, int code, int status) {
                            "EXIT_STATUS=%i", status,
                            NULL);
 
-                if (f != SERVICE_SUCCESS)
+                if (s->result == SERVICE_SUCCESS)
                         s->result = f;
 
                 if (s->main_command &&
@@ -2737,7 +2726,7 @@ static void service_sigchld_event(Unit *u, pid_t pid, int code, int status) {
                               "Control process exited, code=%s status=%i",
                               sigchld_code_to_string(code), status);
 
-                if (f != SERVICE_SUCCESS)
+                if (s->result == SERVICE_SUCCESS)
                         s->result = f;
 
                 /* Immediately get rid of the cgroup, so that the
diff --git a/src/core/socket.c b/src/core/socket.c
index 7f3f154a16..50872e8366 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -1749,12 +1749,10 @@ static int socket_spawn(Socket *s, ExecCommand *c, pid_t *_pid) {
         pid_t pid;
         int r;
         ExecParameters exec_params = {
-                .apply_permissions = true,
-                .apply_chroot      = true,
-                .apply_tty_stdin   = true,
-                .stdin_fd          = -1,
-                .stdout_fd         = -1,
-                .stderr_fd         = -1,
+                .flags      = EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_APPLY_TTY_STDIN,
+                .stdin_fd   = -1,
+                .stdout_fd  = -1,
+                .stderr_fd  = -1,
         };
 
         assert(s);
@@ -1785,7 +1783,7 @@ static int socket_spawn(Socket *s, ExecCommand *c, pid_t *_pid) {
 
         exec_params.argv = argv;
         exec_params.environment = UNIT(s)->manager->environment;
-        exec_params.confirm_spawn = UNIT(s)->manager->confirm_spawn;
+        exec_params.flags |= UNIT(s)->manager->confirm_spawn ? EXEC_CONFIRM_SPAWN : 0;
         exec_params.cgroup_supported = UNIT(s)->manager->cgroup_supported;
         exec_params.cgroup_path = UNIT(s)->cgroup_path;
         exec_params.cgroup_delegate = s->cgroup_context.delegate;
@@ -1897,7 +1895,7 @@ fail:
 static void socket_enter_dead(Socket *s, SocketResult f) {
         assert(s);
 
-        if (f != SOCKET_SUCCESS)
+        if (s->result == SOCKET_SUCCESS)
                 s->result = f;
 
         socket_set_state(s, s->result != SOCKET_SUCCESS ? SOCKET_FAILED : SOCKET_DEAD);
@@ -1916,7 +1914,7 @@ static void socket_enter_stop_post(Socket *s, SocketResult f) {
         int r;
         assert(s);
 
-        if (f != SOCKET_SUCCESS)
+        if (s->result == SOCKET_SUCCESS)
                 s->result = f;
 
         socket_unwatch_control_pid(s);
@@ -1944,7 +1942,7 @@ static void socket_enter_signal(Socket *s, SocketState state, SocketResult f) {
 
         assert(s);
 
-        if (f != SOCKET_SUCCESS)
+        if (s->result == SOCKET_SUCCESS)
                 s->result = f;
 
         r = unit_kill_context(
@@ -1988,7 +1986,7 @@ static void socket_enter_stop_pre(Socket *s, SocketResult f) {
         int r;
         assert(s);
 
-        if (f != SOCKET_SUCCESS)
+        if (s->result == SOCKET_SUCCESS)
                 s->result = f;
 
         socket_unwatch_control_pid(s);
@@ -2770,7 +2768,7 @@ static void socket_sigchld_event(Unit *u, pid_t pid, int code, int status) {
                       "Control process exited, code=%s status=%i",
                       sigchld_code_to_string(code), status);
 
-        if (f != SOCKET_SUCCESS)
+        if (s->result == SOCKET_SUCCESS)
                 s->result = f;
 
         if (s->control_command &&
diff --git a/src/core/swap.c b/src/core/swap.c
index 66a318d01f..2c802da3b5 100644
--- a/src/core/swap.c
+++ b/src/core/swap.c
@@ -611,12 +611,10 @@ static int swap_spawn(Swap *s, ExecCommand *c, pid_t *_pid) {
         pid_t pid;
         int r;
         ExecParameters exec_params = {
-                .apply_permissions = true,
-                .apply_chroot      = true,
-                .apply_tty_stdin   = true,
-                .stdin_fd          = -1,
-                .stdout_fd         = -1,
-                .stderr_fd         = -1,
+                .flags     = EXEC_APPLY_PERMISSIONS|EXEC_APPLY_CHROOT|EXEC_APPLY_TTY_STDIN,
+                .stdin_fd  = -1,
+                .stdout_fd = -1,
+                .stderr_fd = -1,
         };
 
         assert(s);
@@ -642,7 +640,7 @@ static int swap_spawn(Swap *s, ExecCommand *c, pid_t *_pid) {
                 goto fail;
 
         exec_params.environment = UNIT(s)->manager->environment;
-        exec_params.confirm_spawn = UNIT(s)->manager->confirm_spawn;
+        exec_params.flags |= UNIT(s)->manager->confirm_spawn ? EXEC_CONFIRM_SPAWN : 0;
         exec_params.cgroup_supported = UNIT(s)->manager->cgroup_supported;
         exec_params.cgroup_path = UNIT(s)->cgroup_path;
         exec_params.cgroup_delegate = s->cgroup_context.delegate;
@@ -675,7 +673,7 @@ fail:
 static void swap_enter_dead(Swap *s, SwapResult f) {
         assert(s);
 
-        if (f != SWAP_SUCCESS)
+        if (s->result == SWAP_SUCCESS)
                 s->result = f;
 
         swap_set_state(s, s->result != SWAP_SUCCESS ? SWAP_FAILED : SWAP_DEAD);
@@ -691,7 +689,7 @@ static void swap_enter_dead(Swap *s, SwapResult f) {
 static void swap_enter_active(Swap *s, SwapResult f) {
         assert(s);
 
-        if (f != SWAP_SUCCESS)
+        if (s->result == SWAP_SUCCESS)
                 s->result = f;
 
         swap_set_state(s, SWAP_ACTIVE);
@@ -702,7 +700,7 @@ static void swap_enter_signal(Swap *s, SwapState state, SwapResult f) {
 
         assert(s);
 
-        if (f != SWAP_SUCCESS)
+        if (s->result == SWAP_SUCCESS)
                 s->result = f;
 
         r = unit_kill_context(
@@ -999,7 +997,7 @@ static void swap_sigchld_event(Unit *u, pid_t pid, int code, int status) {
         else
                 assert_not_reached("Unknown code");
 
-        if (f != SWAP_SUCCESS)
+        if (s->result == SWAP_SUCCESS)
                 s->result = f;
 
         if (s->control_command) {
diff --git a/src/core/timer.c b/src/core/timer.c
index 3206296f09..e2b43f02f8 100644
--- a/src/core/timer.c
+++ b/src/core/timer.c
@@ -291,7 +291,7 @@ static int timer_coldplug(Unit *u) {
 static void timer_enter_dead(Timer *t, TimerResult f) {
         assert(t);
 
-        if (f != TIMER_SUCCESS)
+        if (t->result == TIMER_SUCCESS)
                 t->result = f;
 
         timer_set_state(t, t->result != TIMER_SUCCESS ? TIMER_FAILED : TIMER_DEAD);
diff --git a/src/coredump/coredumpctl.c b/src/coredump/coredumpctl.c
index 27b1e0fb3f..bbf8793e57 100644
--- a/src/coredump/coredumpctl.c
+++ b/src/coredump/coredumpctl.c
@@ -30,6 +30,7 @@
 #include "compress.h"
 #include "fd-util.h"
 #include "fileio.h"
+#include "fs-util.h"
 #include "journal-internal.h"
 #include "log.h"
 #include "macro.h"
@@ -609,7 +610,13 @@ static int save_core(sd_journal *j, int fd, char **path, bool *unlink_temp) {
                 char *temp = NULL;
 
                 if (fd < 0) {
-                        temp = strdup("/var/tmp/coredump-XXXXXX");
+                        const char *vt;
+
+                        r = var_tmp_dir(&vt);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to acquire temporary directory path: %m");
+
+                        temp = strjoin(vt, "/coredump-XXXXXX", NULL);
                         if (!temp)
                                 return log_oom();
 
diff --git a/src/journal/journal-verify.c b/src/journal/journal-verify.c
index f61f158e8a..4105abfccc 100644
--- a/src/journal/journal-verify.c
+++ b/src/journal/journal-verify.c
@@ -826,7 +826,7 @@ int journal_file_verify(
         int data_fd = -1, entry_fd = -1, entry_array_fd = -1;
         unsigned i;
         bool found_last = false;
-        _cleanup_free_ char *tmp_dir = NULL;
+        const char *tmp_dir = NULL;
 
 #ifdef HAVE_GCRYPT
         uint64_t last_tag = 0;
@@ -846,7 +846,7 @@ int journal_file_verify(
         } else if (f->seal)
                 return -ENOKEY;
 
-        r = var_tmp(&tmp_dir);
+        r = var_tmp_dir(&tmp_dir);
         if (r < 0) {
                 log_error_errno(r, "Failed to determine temporary directory: %m");
                 goto fail;
diff --git a/src/machine/machined-dbus.c b/src/machine/machined-dbus.c
index 1923e8b971..5e2462cba2 100644
--- a/src/machine/machined-dbus.c
+++ b/src/machine/machined-dbus.c
@@ -954,7 +954,7 @@ static int method_clean_pool(sd_bus_message *message, void *userdata, sd_bus_err
         /* Create a temporary file we can dump information about deleted images into. We use a temporary file for this
          * instead of a pipe or so, since this might grow quit large in theory and we don't want to process this
          * continuously */
-        result_fd = open_tmpfile_unlinkable("/tmp/", O_RDWR|O_CLOEXEC);
+        result_fd = open_tmpfile_unlinkable(NULL, O_RDWR|O_CLOEXEC);
         if (result_fd < 0)
                 return -errno;
 
diff --git a/src/nss-systemd/nss-systemd.c b/src/nss-systemd/nss-systemd.c
index e7a4393bb0..7078c0c50c 100644
--- a/src/nss-systemd/nss-systemd.c
+++ b/src/nss-systemd/nss-systemd.c
@@ -26,9 +26,52 @@
 #include "macro.h"
 #include "nss-util.h"
 #include "signal-util.h"
+#include "string-util.h"
 #include "user-util.h"
 #include "util.h"
 
+#ifndef NOBODY_USER_NAME
+#define NOBODY_USER_NAME "nobody"
+#endif
+
+#ifndef NOBODY_GROUP_NAME
+#define NOBODY_GROUP_NAME "nobody"
+#endif
+
+static const struct passwd root_passwd = {
+        .pw_name = (char*) "root",
+        .pw_passwd = (char*) "x", /* see shadow file */
+        .pw_uid = 0,
+        .pw_gid = 0,
+        .pw_gecos = (char*) "Super User",
+        .pw_dir = (char*) "/root",
+        .pw_shell = (char*) "/bin/sh",
+};
+
+static const struct passwd nobody_passwd = {
+        .pw_name = (char*) NOBODY_USER_NAME,
+        .pw_passwd = (char*) "*", /* locked */
+        .pw_uid = 65534,
+        .pw_gid = 65534,
+        .pw_gecos = (char*) "User Nobody",
+        .pw_dir = (char*) "/",
+        .pw_shell = (char*) "/sbin/nologin",
+};
+
+static const struct group root_group = {
+        .gr_name = (char*) "root",
+        .gr_gid = 0,
+        .gr_passwd = (char*) "x", /* see shadow file */
+        .gr_mem = (char*[]) { NULL },
+};
+
+static const struct group nobody_group = {
+        .gr_name = (char*) NOBODY_GROUP_NAME,
+        .gr_gid = 65534,
+        .gr_passwd = (char*) "*", /* locked */
+        .gr_mem = (char*[]) { NULL },
+};
+
 NSS_GETPW_PROTOTYPES(systemd);
 NSS_GETGR_PROTOTYPES(systemd);
 
@@ -50,6 +93,23 @@ enum nss_status _nss_systemd_getpwnam_r(
         assert(name);
         assert(pwd);
 
+        if (!valid_user_group_name(name)) {
+                r = -EINVAL;
+                goto fail;
+        }
+
+        /* Synthesize entries for the root and nobody users, in case they are missing in /etc/passwd */
+        if (streq(name, root_passwd.pw_name)) {
+                *pwd = root_passwd;
+                *errnop = 0;
+                return NSS_STATUS_SUCCESS;
+        }
+        if (streq(name, nobody_passwd.pw_name)) {
+                *pwd = nobody_passwd;
+                *errnop = 0;
+                return NSS_STATUS_SUCCESS;
+        }
+
         /* Make sure that we don't go in circles when allocating a dynamic UID by checking our own database */
         if (getenv_bool("SYSTEMD_NSS_DYNAMIC_BYPASS") > 0)
                 goto not_found;
@@ -126,6 +186,18 @@ enum nss_status _nss_systemd_getpwuid_r(
                 goto fail;
         }
 
+        /* Synthesize data for the root user and for nobody in case they are missing from /etc/passwd */
+        if (uid == root_passwd.pw_uid) {
+                *pwd = root_passwd;
+                *errnop = 0;
+                return NSS_STATUS_SUCCESS;
+        }
+        if (uid == nobody_passwd.pw_uid) {
+                *pwd = nobody_passwd;
+                *errnop = 0;
+                return NSS_STATUS_SUCCESS;
+        }
+
         if (uid <= SYSTEM_UID_MAX)
                 goto not_found;
 
@@ -202,6 +274,23 @@ enum nss_status _nss_systemd_getgrnam_r(
         assert(name);
         assert(gr);
 
+        if (!valid_user_group_name(name)) {
+                r = -EINVAL;
+                goto fail;
+        }
+
+        /* Synthesize records for root and nobody, in case they are missing form /etc/group */
+        if (streq(name, root_group.gr_name)) {
+                *gr = root_group;
+                *errnop = 0;
+                return NSS_STATUS_SUCCESS;
+        }
+        if (streq(name, nobody_group.gr_name)) {
+                *gr = nobody_group;
+                *errnop = 0;
+                return NSS_STATUS_SUCCESS;
+        }
+
         if (getenv_bool("SYSTEMD_NSS_DYNAMIC_BYPASS") > 0)
                 goto not_found;
 
@@ -275,6 +364,18 @@ enum nss_status _nss_systemd_getgrgid_r(
                 goto fail;
         }
 
+        /* Synthesize records for root and nobody, in case they are missing from /etc/group */
+        if (gid == root_group.gr_gid) {
+                *gr = root_group;
+                *errnop = 0;
+                return NSS_STATUS_SUCCESS;
+        }
+        if (gid == nobody_group.gr_gid) {
+                *gr = nobody_group;
+                *errnop = 0;
+                return NSS_STATUS_SUCCESS;
+        }
+
         if (gid <= SYSTEM_GID_MAX)
                 goto not_found;
 
diff --git a/src/test/test-fs-util.c b/src/test/test-fs-util.c
index e0c040f39b..93eec3ef9c 100644
--- a/src/test/test-fs-util.c
+++ b/src/test/test-fs-util.c
@@ -83,47 +83,35 @@ static void test_get_files_in_directory(void) {
 }
 
 static void test_var_tmp(void) {
-        char *tmp_dir = NULL;
-        char *tmpdir_backup = NULL;
-        const char *default_var_tmp = NULL;
-        const char *var_name;
-        bool do_overwrite = true;
-
-        default_var_tmp = "/var/tmp";
-        var_name = "TMPDIR";
-
-        if (getenv(var_name) != NULL) {
-                tmpdir_backup = strdup(getenv(var_name));
-                assert_se(tmpdir_backup != NULL);
-        }
-
-        unsetenv(var_name);
+        _cleanup_free_ char *tmpdir_backup = NULL;
+        const char *tmp_dir = NULL, *t;
 
-        var_tmp(&tmp_dir);
-        assert_se(!strcmp(tmp_dir, default_var_tmp));
-
-        free(tmp_dir);
+        t = getenv("TMPDIR");
+        if (t) {
+                tmpdir_backup = strdup(t);
+                assert_se(tmpdir_backup);
+        }
 
-        setenv(var_name, "/tmp", do_overwrite);
-        assert_se(!strcmp(getenv(var_name), "/tmp"));
+        assert(unsetenv("TMPDIR") >= 0);
 
-        var_tmp(&tmp_dir);
-        assert_se(!strcmp(tmp_dir, "/tmp"));
+        assert_se(var_tmp_dir(&tmp_dir) >= 0);
+        assert_se(streq(tmp_dir, "/var/tmp"));
 
-        free(tmp_dir);
+        assert_se(setenv("TMPDIR", "/tmp", true) >= 0);
+        assert_se(streq(getenv("TMPDIR"), "/tmp"));
 
-        setenv(var_name, "/88_does_not_exist_88", do_overwrite);
-        assert_se(!strcmp(getenv(var_name), "/88_does_not_exist_88"));
+        assert_se(var_tmp_dir(&tmp_dir) >= 0);
+        assert_se(streq(tmp_dir, "/tmp"));
 
-        var_tmp(&tmp_dir);
-        assert_se(!strcmp(tmp_dir, default_var_tmp));
+        assert_se(setenv("TMPDIR", "/88_does_not_exist_88", true) >= 0);
+        assert_se(streq(getenv("TMPDIR"), "/88_does_not_exist_88"));
 
-        free(tmp_dir);
+        assert_se(var_tmp_dir(&tmp_dir) >= 0);
+        assert_se(streq(tmp_dir, "/var/tmp"));
 
-        if (tmpdir_backup != NULL)  {
-                setenv(var_name, tmpdir_backup, do_overwrite);
-                assert_se(!strcmp(getenv(var_name), tmpdir_backup));
-                free(tmpdir_backup);
+        if (tmpdir_backup)  {
+                assert_se(setenv("TMPDIR", tmpdir_backup, true) >= 0);
+                assert_se(streq(getenv("TMPDIR"), tmpdir_backup));
         }
 }