sd-bus: properly handle creds that are known but undefined for a process

A number of fields do not apply to all processes, including: there a
processes without a controlling tty, without parent process, without
service, user services or session. To distuingish these cases from the
case where we simply don't have the data, always return ENXIO for them,
while returning ENODATA for the case where we really lack the
information.

Also update the credentials dumping code to show this properly. Fields
that are known but do not apply are now shown as "n/a".

Note that this also changes some of the calls in process-util.c and
cgroup-util.c to return ENXIO for these cases.

2 files changed, 15 insertions, 16 deletions

diff --git a/src/test/test-cgroup-util.c b/src/test/test-cgroup-util.c
index aca4f868a1..fff9ec22cf 100644
--- a/src/test/test-cgroup-util.c
+++ b/src/test/test-cgroup-util.c
@@ -40,11 +40,11 @@ static void test_path_decode_unit(void) {
         check_p_d_u("getty@tty2.service", 0, "getty@tty2.service");
         check_p_d_u("getty@tty2.service/", 0, "getty@tty2.service");
         check_p_d_u("getty@tty2.service/xxx", 0, "getty@tty2.service");
-        check_p_d_u("getty@.service/", -EINVAL, NULL);
-        check_p_d_u("getty@.service", -EINVAL, NULL);
+        check_p_d_u("getty@.service/", -ENXIO, NULL);
+        check_p_d_u("getty@.service", -ENXIO, NULL);
         check_p_d_u("getty.service", 0, "getty.service");
-        check_p_d_u("getty", -EINVAL, NULL);
-        check_p_d_u("getty/waldo", -EINVAL, NULL);
+        check_p_d_u("getty", -ENXIO, NULL);
+        check_p_d_u("getty/waldo", -ENXIO, NULL);
         check_p_d_u("_cpu.service", 0, "cpu.service");
 }
 
@@ -64,12 +64,12 @@ static void test_path_get_unit(void) {
         check_p_g_u("/system.slice/getty@tty5.service/aaa/bbb", 0, "getty@tty5.service");
         check_p_g_u("/system.slice/getty@tty5.service/", 0, "getty@tty5.service");
         check_p_g_u("/system.slice/getty@tty6.service/tty5", 0, "getty@tty6.service");
-        check_p_g_u("sadfdsafsda", -EINVAL, NULL);
-        check_p_g_u("/system.slice/getty####@tty6.service/xxx", -EINVAL, NULL);
+        check_p_g_u("sadfdsafsda", -ENXIO, NULL);
+        check_p_g_u("/system.slice/getty####@tty6.service/xxx", -ENXIO, NULL);
         check_p_g_u("/system.slice/system-waldo.slice/foobar.service/sdfdsaf", 0, "foobar.service");
         check_p_g_u("/system.slice/system-waldo.slice/_cpu.service/sdfdsaf", 0, "cpu.service");
         check_p_g_u("/user.slice/user-1000.slice/user@1000.service/server.service", 0, "user@1000.service");
-        check_p_g_u("/user.slice/user-1000.slice/user@.service/server.service", -EINVAL, NULL);
+        check_p_g_u("/user.slice/user-1000.slice/user@.service/server.service", -ENXIO, NULL);
 }
 
 static void check_p_g_u_u(const char *path, int code, const char *result) {
@@ -87,15 +87,15 @@ static void test_path_get_user_unit(void) {
         check_p_g_u_u("/user.slice/user-1000.slice/session-2.scope/waldo.slice/foobar.service", 0, "foobar.service");
         check_p_g_u_u("/user.slice/user-1002.slice/session-2.scope/foobar.service/waldo", 0, "foobar.service");
         check_p_g_u_u("/user.slice/user-1000.slice/session-2.scope/foobar.service/waldo/uuuux", 0, "foobar.service");
-        check_p_g_u_u("/user.slice/user-1000.slice/session-2.scope/waldo/waldo/uuuux", -EINVAL, NULL);
+        check_p_g_u_u("/user.slice/user-1000.slice/session-2.scope/waldo/waldo/uuuux", -ENXIO, NULL);
         check_p_g_u_u("/user.slice/user-1000.slice/session-2.scope/foobar@pie.service/pa/po", 0, "foobar@pie.service");
         check_p_g_u_u("/session-2.scope/foobar@pie.service/pa/po", 0, "foobar@pie.service");
         check_p_g_u_u("/xyz.slice/xyz-waldo.slice/session-77.scope/foobar@pie.service/pa/po", 0, "foobar@pie.service");
-        check_p_g_u_u("/meh.service", -ENOENT, NULL);
+        check_p_g_u_u("/meh.service", -ENXIO, NULL);
         check_p_g_u_u("/session-3.scope/_cpu.service", 0, "cpu.service");
         check_p_g_u_u("/user.slice/user-1000.slice/user@1000.service/server.service", 0, "server.service");
         check_p_g_u_u("/user.slice/user-1000.slice/user@1000.service/foobar.slice/foobar@pie.service", 0, "foobar@pie.service");
-        check_p_g_u_u("/user.slice/user-1000.slice/user@.service/server.service", -ENOENT, NULL);
+        check_p_g_u_u("/user.slice/user-1000.slice/user@.service/server.service", -ENXIO, NULL);
 }
 
 static void check_p_g_s(const char *path, int code, const char *result) {
@@ -108,8 +108,8 @@ static void check_p_g_s(const char *path, int code, const char *result) {
 static void test_path_get_session(void) {
         check_p_g_s("/user.slice/user-1000.slice/session-2.scope/foobar.service", 0, "2");
         check_p_g_s("/session-3.scope", 0, "3");
-        check_p_g_s("/session-.scope", -ENOENT, NULL);
-        check_p_g_s("", -ENOENT, NULL);
+        check_p_g_s("/session-.scope", -ENXIO, NULL);
+        check_p_g_s("", -ENXIO, NULL);
 }
 
 static void check_p_g_o_u(const char *path, int code, uid_t result) {
@@ -122,7 +122,7 @@ static void check_p_g_o_u(const char *path, int code, uid_t result) {
 static void test_path_get_owner_uid(void) {
         check_p_g_o_u("/user.slice/user-1000.slice/session-2.scope/foobar.service", 0, 1000);
         check_p_g_o_u("/user.slice/user-1006.slice", 0, 1006);
-        check_p_g_o_u("", -ENOENT, 0);
+        check_p_g_o_u("", -ENXIO, 0);
 }
 
 static void test_get_paths(void) {
diff --git a/src/test/test-process-util.c b/src/test/test-process-util.c
index 1de100cdae..e4e2efecd5 100644
--- a/src/test/test-process-util.c
+++ b/src/test/test-process-util.c
@@ -44,9 +44,8 @@ static void test_get_process_comm(void) {
         if (stat("/proc/1/comm", &st) == 0) {
                 assert_se(get_process_comm(1, &a) >= 0);
                 log_info("pid1 comm: '%s'", a);
-        } else {
+        } else
                 log_warning("/proc/1/comm does not exist.");
-        }
 
         assert_se(get_process_cmdline(1, 0, true, &c) >= 0);
         log_info("pid1 cmdline: '%s'", c);
@@ -87,7 +86,7 @@ static void test_get_process_comm(void) {
         log_info("self strlen(environ): '%zu'", strlen(env));
 
         if (!detect_container(NULL))
-                assert_se(get_ctty_devnr(1, &h) == -ENOENT);
+                assert_se(get_ctty_devnr(1, &h) == -ENXIO);
 
         getenv_for_pid(1, "PATH", &i);
         log_info("pid1 $PATH: '%s'", strna(i));