path-lookup: if $HOME can be determined but $XDG_RUNTIME_DIR can't, is it

So far, if either $HOME or $XDG_RUNTIME_DIR is not set we wouldn't use
either, and fail acquire_config_dirs() and acquire_control_dirs() in
their entireties. With this change, let's make use of the variables we
can acquire, and don't bother with the other.

Specifically this means: in both acquire_config_dirs() and
acquire_control_dirs() handle ENXIO from user_config_dir() and
user_runtime_dir() directly, instead of propagating it up and handling
it in the caller.

1 files changed, 24 insertions, 8 deletions

diff --git a/src/shared/path-lookup.c b/src/shared/path-lookup.c
index 7f0751d3a1..09a44534e2 100644
--- a/src/shared/path-lookup.c
+++ b/src/shared/path-lookup.c
@@ -329,12 +329,18 @@ static int acquire_config_dirs(UnitFileScope scope, char **persistent, char **ru
 
         case UNIT_FILE_USER:
                 r = user_config_dir(&a, "/systemd/user");
-                if (r < 0)
+                if (r < 0 && r != -ENXIO)
                         return r;
 
                 r = user_runtime_dir(runtime, "/systemd/user");
-                if (r < 0)
-                        return r;
+                if (r < 0) {
+                        if (r != -ENXIO)
+                                return r;
+
+                        /* If XDG_RUNTIME_DIR is not set, don't consider that fatal, simply initialize the runtime
+                         * directory to NULL */
+                        *runtime = NULL;
+                }
 
                 *persistent = a;
                 a = NULL;
@@ -383,12 +389,18 @@ static int acquire_control_dirs(UnitFileScope scope, char **persistent, char **r
 
         case UNIT_FILE_USER:
                 r = user_config_dir(&a, "/systemd/system.control");
-                if (r < 0)
+                if (r < 0 && r != -ENXIO)
                         return r;
 
                 r = user_runtime_dir(runtime, "/systemd/system.control");
-                if (r < 0)
-                        return r;
+                if (r < 0) {
+                        if (r != -ENXIO)
+                                return r;
+
+                        /* If XDG_RUNTIME_DIR is not set, don't consider this fatal, simply initialize the directory to
+                         * NULL */
+                        *runtime = NULL;
+                }
 
                 break;
 
@@ -475,22 +487,26 @@ int lookup_paths_init(
                         return -ENOMEM;
         }
 
+        /* Note: when XDG_RUNTIME_DIR is not set this will not return -ENXIO, but simply set runtime_config to NULL */
         r = acquire_config_dirs(scope, &persistent_config, &runtime_config);
-        if (r < 0 && r != -ENXIO)
+        if (r < 0)
                 return r;
 
         if ((flags & LOOKUP_PATHS_EXCLUDE_GENERATED) == 0) {
+                /* Note: if XDG_RUNTIME_DIR is not set, this will fail completely with ENXIO */
                 r = acquire_generator_dirs(scope, &generator, &generator_early, &generator_late);
                 if (r < 0 && r != -EOPNOTSUPP && r != -ENXIO)
                         return r;
         }
 
+        /* Note: if XDG_RUNTIME_DIR is not set, this will fail completely with ENXIO */
         r = acquire_transient_dir(scope, &transient);
         if (r < 0 && r != -EOPNOTSUPP && r != -ENXIO)
                 return r;
 
+        /* Note: when XDG_RUNTIME_DIR is not set this will not return -ENXIO, but simply set runtime_control to NULL */
         r = acquire_control_dirs(scope, &persistent_control, &runtime_control);
-        if (r < 0 && r != -EOPNOTSUPP && r != -ENXIO)
+        if (r < 0 && r != -EOPNOTSUPP)
                 return r;
 
         /* First priority is whatever has been passed to us via env vars */