tree-wide: use -EINVAL for enum invalid values

As suggested in https://github.com/systemd/systemd/pull/11484#issuecomment-775288617.

This does not touch anything exposed in src/systemd. Changing the defines there
would be a compatibility break.

Note that tests are broken after this commit. They will be fixed in the next one.

4 files changed, 9 insertions, 9 deletions

diff --git a/src/login/logind-action.h b/src/login/logind-action.h
index 73aa20bbb4..0baad37a84 100644
--- a/src/login/logind-action.h
+++ b/src/login/logind-action.h
@@ -15,7 +15,7 @@ typedef enum HandleAction {
         HANDLE_SUSPEND_THEN_HIBERNATE,
         HANDLE_LOCK,
         _HANDLE_ACTION_MAX,
-        _HANDLE_ACTION_INVALID = -1
+        _HANDLE_ACTION_INVALID = -EINVAL,
 } HandleAction;
 
 #include "logind-inhibit.h"
diff --git a/src/login/logind-inhibit.h b/src/login/logind-inhibit.h
index 124bdb662f..871e69a03a 100644
--- a/src/login/logind-inhibit.h
+++ b/src/login/logind-inhibit.h
@@ -13,14 +13,14 @@ typedef enum InhibitWhat {
         INHIBIT_HANDLE_LID_SWITCH    = 1 << 6,
         INHIBIT_HANDLE_REBOOT_KEY    = 1 << 7,
         _INHIBIT_WHAT_MAX            = 1 << 8,
-        _INHIBIT_WHAT_INVALID        = -1
+        _INHIBIT_WHAT_INVALID        = -EINVAL,
 } InhibitWhat;
 
 typedef enum InhibitMode {
         INHIBIT_BLOCK,
         INHIBIT_DELAY,
         _INHIBIT_MODE_MAX,
-        _INHIBIT_MODE_INVALID = -1
+        _INHIBIT_MODE_INVALID = -EINVAL,
 } InhibitMode;
 
 #include "logind.h"
diff --git a/src/login/logind-session.h b/src/login/logind-session.h
index 1b59bdbe74..5c35071dc5 100644
--- a/src/login/logind-session.h
+++ b/src/login/logind-session.h
@@ -15,7 +15,7 @@ typedef enum SessionState {
         SESSION_ACTIVE,   /* Logged in and in the fg */
         SESSION_CLOSING,  /* Logged out, but scope is still there */
         _SESSION_STATE_MAX,
-        _SESSION_STATE_INVALID = -1
+        _SESSION_STATE_INVALID = -EINVAL,
 } SessionState;
 
 typedef enum SessionClass {
@@ -24,7 +24,7 @@ typedef enum SessionClass {
         SESSION_LOCK_SCREEN,
         SESSION_BACKGROUND,
         _SESSION_CLASS_MAX,
-        _SESSION_CLASS_INVALID = -1
+        _SESSION_CLASS_INVALID = -EINVAL,
 } SessionClass;
 
 typedef enum SessionType {
@@ -35,7 +35,7 @@ typedef enum SessionType {
         SESSION_MIR,
         SESSION_WEB,
         _SESSION_TYPE_MAX,
-        _SESSION_TYPE_INVALID = -1
+        _SESSION_TYPE_INVALID = -EINVAL,
 } SessionType;
 
 #define SESSION_TYPE_IS_GRAPHICAL(type) IN_SET(type, SESSION_X11, SESSION_WAYLAND, SESSION_MIR)
@@ -44,7 +44,7 @@ enum KillWho {
         KILL_LEADER,
         KILL_ALL,
         _KILL_WHO_MAX,
-        _KILL_WHO_INVALID = -1
+        _KILL_WHO_INVALID = -EINVAL,
 };
 
 typedef enum TTYValidity {
@@ -52,7 +52,7 @@ typedef enum TTYValidity {
         TTY_FROM_UTMP,
         TTY_UTMP_INCONSISTENT, /* may happen on ssh sessions with multiplexed TTYs */
         _TTY_VALIDITY_MAX,
-        _TTY_VALIDITY_INVALID = -1,
+        _TTY_VALIDITY_INVALID = -EINVAL,
 } TTYValidity;
 
 struct Session {
diff --git a/src/login/logind-user.h b/src/login/logind-user.h
index 2c5f993faa..21b9f8f348 100644
--- a/src/login/logind-user.h
+++ b/src/login/logind-user.h
@@ -16,7 +16,7 @@ typedef enum UserState {
         USER_ACTIVE,     /* User logged in and has a session in the fg */
         USER_CLOSING,    /* User logged out, but processes still remain and lingering is not enabled */
         _USER_STATE_MAX,
-        _USER_STATE_INVALID = -1
+        _USER_STATE_INVALID = -EINVAL,
 } UserState;
 
 struct User {