portable: Enable unpriv operation

This does not yet support directory images properly
as systemd itself does not support unpriv directory
images properly yet.

The user profiles are a copy of the system profiles but without
DynamicUser=yes (can't be used by user managers) and without
ProtectHome=yes (this masks /home which breaks StateDirectory= which
is lcoated inside /home)

src/shared/discover-image.c

@@ -663,7 +663,7 @@ static int pick_image_search_path(
         }
 
         case RUNTIME_SCOPE_USER: {
-                if (class != IMAGE_MACHINE)
+                if (!IN_SET(class, IMAGE_MACHINE, IMAGE_PORTABLE))
                         break;
 
                 static const uint64_t dirs[] = {
@@ -676,7 +676,7 @@ static int pick_image_search_path(
                 FOREACH_ELEMENT(d, dirs) {
                         _cleanup_free_ char *p = NULL;
 
-                        r = sd_path_lookup(*d, "machines", &p);
+                        r = sd_path_lookup(*d, image_dirname_to_string(class), &p);
                         if (r == -ENXIO) /* No XDG_RUNTIME_DIR set */
                                 continue;
                         if (r < 0)

src/shared/dissect-image.c

@@ -4512,7 +4512,7 @@ Architecture dissected_image_architecture(DissectedImage *m) {
 }
 
 bool dissected_image_is_portable(DissectedImage *m) {
-        return m && strv_env_pairs_get(m->os_release, "PORTABLE_PREFIXES");
+        return m && (strv_env_pairs_get(m->os_release, "PORTABLE_PREFIXES") || strv_env_pairs_get(m->os_release, "PORTABLE_SCOPE"));
 }
 
 bool dissected_image_is_initrd(DissectedImage *m) {

src/shared/portable-util.c

@@ -5,10 +5,70 @@
 #include "alloc-util.h"
 #include "fs-util.h"
 #include "nulstr-util.h"
+#include "path-lookup.h"
 #include "portable-util.h"
 #include "string-util.h"
+#include "strv.h"
 
-int find_portable_profile(const char *name, const char *unit, char **ret_path) {
+int portable_profile_dirs(RuntimeScope scope, char ***ret) {
+        _cleanup_strv_free_ char **dirs = NULL;
+        int r;
+
+        assert(ret);
+
+        switch (scope) {
+
+        case RUNTIME_SCOPE_SYSTEM:
+                r = strv_from_nulstr(&dirs, PORTABLE_PROFILE_DIRS);
+                if (r < 0)
+                        return r;
+
+                break;
+
+        case RUNTIME_SCOPE_USER: {
+                _cleanup_free_ char *d = NULL;
+
+                r = xdg_user_config_dir("systemd/portable/profile", &d);
+                if (r < 0 && r != -ENXIO)
+                        return r;
+                if (r >= 0) {
+                        r = strv_consume(&dirs, TAKE_PTR(d));
+                        if (r < 0)
+                                return r;
+                }
+
+                r = xdg_user_runtime_dir("systemd/portable/profile", &d);
+                if (r < 0 && r != -ENXIO)
+                        return r;
+                if (r >= 0) {
+                        r = strv_consume(&dirs, TAKE_PTR(d));
+                        if (r < 0)
+                                return r;
+                }
+
+                _fallthrough_;
+        }
+
+        case RUNTIME_SCOPE_GLOBAL:
+                r = strv_extend_strv(
+                                &dirs,
+                                CONF_PATHS_STRV("systemd/user/portable/profile"),
+                                /* filter_duplicates= */ false);
+                if (r < 0)
+                        return r;
+
+                break;
+
+        default:
+                return -EINVAL;
+        }
+
+        *ret = TAKE_PTR(dirs);
+        return 0;
+}
+
+int find_portable_profile(RuntimeScope scope, const char *name, const char *unit, char **ret_path) {
+        _cleanup_strv_free_ char **dirs = NULL;
         const char *dot;
         int r;
 
@@ -17,10 +77,14 @@ int find_portable_profile(const char *name, const char *unit, char **ret_path) {
 
         assert_se(dot = strrchr(unit, '.'));
 
-        NULSTR_FOREACH(p, PORTABLE_PROFILE_DIRS) {
+        r = portable_profile_dirs(scope, &dirs);
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(p, dirs) {
                 _cleanup_free_ char *joined = NULL;
 
-                joined = strjoin(p, "/", name, "/", dot + 1, ".conf");
+                joined = strjoin(*p, "/", name, "/", dot + 1, ".conf");
                 if (!joined)
                         return -ENOMEM;
 

src/shared/portable-util.h

@@ -6,4 +6,5 @@
 
 #define PORTABLE_PROFILE_DIRS CONF_PATHS_NULSTR("systemd/portable/profile")
 
-int find_portable_profile(const char *name, const char *unit, char **ret_path);
+int portable_profile_dirs(RuntimeScope scope, char ***ret);
+int find_portable_profile(RuntimeScope scope, const char *name, const char *unit, char **ret_path);