core: make "taint" string logic a bit more generic and output it at boot

The tainting logic existed for a long time, but was hidden inside the
bus interfaces. Let's give it a small bit more coverage, by logging its
value early at boot during initialization.

src/core/dbus-manager.c

@@ -27,7 +27,6 @@
 #include "architecture.h"
 #include "build.h"
 #include "bus-common-errors.h"
-#include "clock-util.h"
 #include "dbus-execute.h"
 #include "dbus-job.h"
 #include "dbus-manager.h"
@@ -140,33 +139,18 @@ static int property_get_tainted(
                 void *userdata,
                 sd_bus_error *error) {
 
-        char buf[sizeof("split-usr:cgroups-missing:local-hwclock:var-run-bad:")] = "", *e = buf;
-        _cleanup_free_ char *destination = NULL;
+        _cleanup_free_ char *s = NULL;
         Manager *m = userdata;
-        int r;
 
         assert(bus);
         assert(reply);
         assert(m);
 
-        if (m->taint_usr)
-                e = stpcpy(e, "split-usr:");
+        s = manager_taint_string(m);
+        if (!s)
+                return log_oom();
 
-        if (access("/proc/cgroups", F_OK) < 0)
-                e = stpcpy(e, "cgroups-missing:");
-
-        if (clock_is_localtime(NULL) > 0)
-                e = stpcpy(e, "local-hwclock:");
-
-        r = readlink_malloc("/var/run", &destination);
-        if (r < 0 || !PATH_IN_SET(destination, "../run", "/run"))
-                e = stpcpy(e, "var-run-bad:");
-
-        /* remove the last ':' */
-        if (e != buf)
-                e[-1] = 0;
-
-        return sd_bus_message_append(reply, "s", buf);
+        return sd_bus_message_append(reply, "s", s);
 }
 
 static int property_get_log_target(

src/core/main.c

@@ -2394,6 +2394,14 @@ int main(int argc, char *argv[]) {
                  "Loaded units and determined initial transaction in %s.",
                  format_timespan(timespan, sizeof(timespan), after_startup - before_startup, 100 * USEC_PER_MSEC));
 
+        if (arg_system) {
+                _cleanup_free_ char *taint;
+
+                taint = manager_taint_string(m);
+                if (!isempty(taint))
+                        log_notice("System is tainted: %s", taint);
+        }
+
         if (arg_action == ACTION_TEST) {
                 printf("-> By units:\n");
                 manager_dump_units(m, stdout, "\t");

src/core/manager.c

@@ -48,6 +48,7 @@
 #include "bus-kernel.h"
 #include "bus-util.h"
 #include "clean-ipc.h"
+#include "clock-util.h"
 #include "dbus-job.h"
 #include "dbus-manager.h"
 #include "dbus-unit.h"
@@ -3851,6 +3852,50 @@ int manager_dispatch_user_lookup_fd(sd_event_source *source, int fd, uint32_t re
         return 0;
 }
 
+char *manager_taint_string(Manager *m) {
+        _cleanup_free_ char *destination = NULL;
+        char *buf, *e;
+        int r;
+
+        assert(m);
+
+        buf = new(char, sizeof("split-usr:"
+                               "cgroups-missing:"
+                               "local-hwclock:"
+                               "var-run-bad:"
+                               "weird-nobody-user:"
+                               "weird-nobody-group:"));
+        if (!buf)
+                return NULL;
+
+        e = buf;
+
+        if (m->taint_usr)
+                e = stpcpy(e, "split-usr:");
+
+        if (access("/proc/cgroups", F_OK) < 0)
+                e = stpcpy(e, "cgroups-missing:");
+
+        if (clock_is_localtime(NULL) > 0)
+                e = stpcpy(e, "local-hwclock:");
+
+        r = readlink_malloc("/var/run", &destination);
+        if (r < 0 || !PATH_IN_SET(destination, "../run", "/run"))
+                e = stpcpy(e, "var-run-bad:");
+
+        if (!streq(NOBODY_USER_NAME, "nobody"))
+                e = stpcpy(e, "weird-nobody-user:");
+
+        if (!streq(NOBODY_GROUP_NAME, "nobody"))
+                e = stpcpy(e, "weird-nobody-group:");
+
+        /* remove the last ':' */
+        if (e != buf)
+                e[-1] = 0;
+
+        return buf;
+}
+
 static const char *const manager_state_table[_MANAGER_STATE_MAX] = {
         [MANAGER_INITIALIZING] = "initializing",
         [MANAGER_STARTING] = "starting",

src/core/manager.h

@@ -435,6 +435,8 @@ void manager_deserialize_uid_refs_one(Manager *m, const char *value);
 void manager_serialize_gid_refs(Manager *m, FILE *f);
 void manager_deserialize_gid_refs_one(Manager *m, const char *value);
 
+char *manager_taint_string(Manager *m);
+
 const char *manager_state_to_string(ManagerState m) _const_;
 ManagerState manager_state_from_string(const char *s) _pure_;