install: follow unit file symlinks in /usr, but not /etc when looking for [Install] data

Some distributions use alias unit files via symlinks in /usr to cover
for legacy service names. With this change we'll allow "systemctl
enable" on such aliases.

Previously, our rule was that symlinks are user configuration that
"systemctl enable" + "systemctl disable" creates and removes, while unit
files is where the instructions to do so are store. As a result of the
rule we'd never read install information through symlinks, since that
would mix enablement state with installation instructions.

Now, the new rule is that only symlinks inside of /etc are
configuration. Unit files, and symlinks in /usr are now valid for
installation instructions.

This patch is quite a rework of the whole install logic, and makes the
following addional changes:

- Adds a complete test "test-instal-root" that tests the install logic
  pretty comprehensively.

- Never uses canonicalize_file_name(), because that's incompatible with
  operation relative to a specific root directory.

- unit_file_get_state() is reworked to return a proper error, and
  returns the state in a call-by-ref parameter. This cleans up confusion
  between the enum type and errno-like errors.

- The new logic puts a limit on how long to follow unit file symlinks:
  it will do so only for 64 steps at max.

- The InstallContext object's fields are renamed to will_process and
  has_processed (will_install and has_installed) since they are also
  used for deinstallation and all kinds of other operations.

- The root directory is always verified before use.

- install.c is reordered to place the exported functions together.

- Stricter rules are followed when traversing symlinks: the unit suffix
  must say identical, and it's not allowed to link between regular units
  and templated units.

- Various modernizations

- The "invalid" unit file state has been renamed to "bad", in order to
  avoid confusion between UNIT_FILE_INVALID and
  _UNIT_FILE_STATE_INVALID. Given that the state should normally not be
  seen and is not documented this should not be a problematic change.
  The new name is now documented however.

Fixes #1375, #1718, #1706

Makefile.am

@@ -1493,7 +1493,8 @@ tests += \
 	test-verbs \
 	test-af-list \
 	test-arphrd-list \
-	test-dns-domain
+	test-dns-domain \
+	test-install-root
 
 EXTRA_DIST += \
 	test/a.service \
@@ -1836,6 +1837,12 @@ test_verbs_SOURCES = \
 test_verbs_LDADD = \
 	libshared.la
 
+test_install_root_SOURCES = \
+	src/test/test-install-root.c
+
+test_install_root_LDADD = \
+	libshared.la
+
 test_namespace_LDADD = \
 	libcore.la
 

man/systemctl.xml

@@ -961,10 +961,11 @@ kobject-uevent 1 systemd-udevd-kernel.socket systemd-udevd.service
           <term><command>list-unit-files <optional><replaceable>PATTERN...</replaceable></optional></command></term>
 
           <listitem>
-            <para>List installed unit files. If one or more
-            <replaceable>PATTERN</replaceable>s are specified, only
-            units whose filename (just the last component of the path)
-            matches one of them are shown.</para>
+            <para>List installed unit files and their enablement state
+            (as reported by <command>is-enabled</command>). If one or
+            more <replaceable>PATTERN</replaceable>s are specified,
+            only units whose filename (just the last component of the
+            path) matches one of them are shown.</para>
           </listitem>
         </varlistentry>
 
@@ -1171,6 +1172,11 @@ kobject-uevent 1 systemd-udevd-kernel.socket systemd-udevd.service
                     <entry>The unit file is not enabled.</entry>
                     <entry>&gt; 0</entry>
                   </row>
+                  <row>
+                    <entry><literal>bad</literal></entry>
+                    <entry>Unit file is invalid or another error occured. Note that <command>is-enabled</command> will not actually return this state, but print an error message instead. However the unit file listing printed by <command>list-unit-files</command> might show it.</entry>
+                    <entry>&gt; 0</entry>
+                  </row>
                 </tbody>
               </tgroup>
             </table>

src/basic/fs-util.c

@@ -233,6 +233,26 @@ int readlink_and_canonicalize(const char *p, char **r) {
         return 0;
 }
 
+int readlink_and_make_absolute_root(const char *root, const char *path, char **ret) {
+        _cleanup_free_ char *target = NULL, *t = NULL;
+        const char *full;
+        int r;
+
+        full = prefix_roota(root, path);
+        r = readlink_malloc(full, &target);
+        if (r < 0)
+                return r;
+
+        t = file_in_same_dir(path, target);
+        if (!t)
+                return -ENOMEM;
+
+        *ret = t;
+        t = NULL;
+
+        return 0;
+}
+
 int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) {
         assert(path);
 

src/basic/fs-util.h

@@ -40,6 +40,7 @@ int readlink_malloc(const char *p, char **r);
 int readlink_value(const char *p, char **ret);
 int readlink_and_make_absolute(const char *p, char **r);
 int readlink_and_canonicalize(const char *p, char **r);
+int readlink_and_make_absolute_root(const char *root, const char *path, char **ret);
 
 int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid);
 int fchmod_and_fchown(int fd, mode_t mode, uid_t uid, gid_t gid);

src/core/dbus-manager.c

@@ -1521,9 +1521,9 @@ static int method_get_unit_file_state(sd_bus_message *message, void *userdata, s
 
         scope = m->running_as == MANAGER_SYSTEM ? UNIT_FILE_SYSTEM : UNIT_FILE_USER;
 
-        state = unit_file_get_state(scope, NULL, name);
-        if (state < 0)
-                return state;
+        r = unit_file_get_state(scope, NULL, name, &state);
+        if (r < 0)
+                return r;
 
         return sd_bus_reply_method_return(message, "s", unit_file_state_to_string(state));
 }

src/core/unit.c

@@ -3148,12 +3148,19 @@ int unit_following_set(Unit *u, Set **s) {
 }
 
 UnitFileState unit_get_unit_file_state(Unit *u) {
+        int r;
+
         assert(u);
 
-        if (u->unit_file_state < 0 && u->fragment_path)
-                u->unit_file_state = unit_file_get_state(
+        if (u->unit_file_state < 0 && u->fragment_path) {
+                r = unit_file_get_state(
                                 u->manager->running_as == MANAGER_SYSTEM ? UNIT_FILE_SYSTEM : UNIT_FILE_USER,
-                                NULL, basename(u->fragment_path));
+                                NULL,
+                                basename(u->fragment_path),
+                                &u->unit_file_state);
+                if (r < 0)
+                        u->unit_file_state = UNIT_FILE_BAD;
+        }
 
         return u->unit_file_state;
 }
@@ -3164,7 +3171,8 @@ int unit_get_unit_file_preset(Unit *u) {
         if (u->unit_file_preset < 0 && u->fragment_path)
                 u->unit_file_preset = unit_file_query_preset(
                                 u->manager->running_as == MANAGER_SYSTEM ? UNIT_FILE_SYSTEM : UNIT_FILE_USER,
-                                NULL, basename(u->fragment_path));
+                                NULL,
+                                basename(u->fragment_path));
 
         return u->unit_file_preset;
 }

src/shared/install.h

@@ -25,13 +25,15 @@ typedef enum UnitFileScope UnitFileScope;
 typedef enum UnitFileState UnitFileState;
 typedef enum UnitFilePresetMode UnitFilePresetMode;
 typedef enum UnitFileChangeType UnitFileChangeType;
+typedef enum UnitFileType UnitFileType;
 typedef struct UnitFileChange UnitFileChange;
 typedef struct UnitFileList UnitFileList;
 typedef struct UnitFileInstallInfo UnitFileInstallInfo;
 
 #include "hashmap.h"
-#include "unit-name.h"
 #include "path-lookup.h"
+#include "strv.h"
+#include "unit-name.h"
 
 enum UnitFileScope {
         UNIT_FILE_SYSTEM,
@@ -51,7 +53,7 @@ enum UnitFileState {
         UNIT_FILE_STATIC,
         UNIT_FILE_DISABLED,
         UNIT_FILE_INDIRECT,
-        UNIT_FILE_INVALID,
+        UNIT_FILE_BAD,
         _UNIT_FILE_STATE_MAX,
         _UNIT_FILE_STATE_INVALID = -1
 };
@@ -82,6 +84,14 @@ struct UnitFileList {
         UnitFileState state;
 };
 
+enum UnitFileType {
+        UNIT_FILE_TYPE_REGULAR,
+        UNIT_FILE_TYPE_SYMLINK,
+        UNIT_FILE_TYPE_MASKED,
+        _UNIT_FILE_TYPE_MAX,
+        _UNIT_FILE_TYPE_INVALID = -1,
+};
+
 struct UnitFileInstallInfo {
         char *name;
         char *path;
@@ -93,8 +103,26 @@ struct UnitFileInstallInfo {
         char **also;
 
         char *default_instance;
+
+        UnitFileType type;
+
+        char *symlink_target;
 };
 
+static inline bool UNIT_FILE_INSTALL_INFO_HAS_RULES(UnitFileInstallInfo *i) {
+        assert(i);
+
+        return !strv_isempty(i->aliases) ||
+               !strv_isempty(i->wanted_by) ||
+               !strv_isempty(i->required_by);
+}
+
+static inline bool UNIT_FILE_INSTALL_INFO_HAS_ALSO(UnitFileInstallInfo *i) {
+        assert(i);
+
+        return !strv_isempty(i->also);
+}
+
 int unit_file_enable(UnitFileScope scope, bool runtime, const char *root_dir, char **files, bool force, UnitFileChange **changes, unsigned *n_changes);
 int unit_file_disable(UnitFileScope scope, bool runtime, const char *root_dir, char **files, UnitFileChange **changes, unsigned *n_changes);
 int unit_file_reenable(UnitFileScope scope, bool runtime, const char *root_dir, char **files, bool force, UnitFileChange **changes, unsigned *n_changes);
@@ -105,14 +133,14 @@ int unit_file_mask(UnitFileScope scope, bool runtime, const char *root_dir, char
 int unit_file_unmask(UnitFileScope scope, bool runtime, const char *root_dir, char **files, UnitFileChange **changes, unsigned *n_changes);
 int unit_file_set_default(UnitFileScope scope, const char *root_dir, const char *file, bool force, UnitFileChange **changes, unsigned *n_changes);
 int unit_file_get_default(UnitFileScope scope, const char *root_dir, char **name);
-int unit_file_add_dependency(UnitFileScope scope, bool runtime, const char *root_dir, char **files, char *target, UnitDependency dep, bool force, UnitFileChange **changes, unsigned *n_changes);
+int unit_file_add_dependency(UnitFileScope scope, bool runtime, const char *root_dir, char **files, const char *target, UnitDependency dep, bool force, UnitFileChange **changes, unsigned *n_changes);
 
-UnitFileState unit_file_lookup_state(UnitFileScope scope, const char *root_dir,const LookupPaths *paths, const char *name);
-UnitFileState unit_file_get_state(UnitFileScope scope, const char *root_dir, const char *filename);
+int unit_file_lookup_state(UnitFileScope scope, const char *root_dir,const LookupPaths *paths, const char *name, UnitFileState *ret);
+int unit_file_get_state(UnitFileScope scope, const char *root_dir, const char *filename, UnitFileState *ret);
 
 int unit_file_get_list(UnitFileScope scope, const char *root_dir, Hashmap *h);
+Hashmap* unit_file_list_free(Hashmap *h);
 
-void unit_file_list_free(Hashmap *h);
 int unit_file_changes_add(UnitFileChange **changes, unsigned *n_changes, UnitFileChangeType type, const char *path, const char *source);
 void unit_file_changes_free(UnitFileChange *changes, unsigned n_changes);
 

src/systemctl/systemctl.c

@@ -1335,7 +1335,7 @@ static void output_unit_file_list(const UnitFileList *units, unsigned c) {
                            UNIT_FILE_MASKED,
                            UNIT_FILE_MASKED_RUNTIME,
                            UNIT_FILE_DISABLED,
-                           UNIT_FILE_INVALID)) {
+                           UNIT_FILE_BAD)) {
                         on  = ansi_highlight_red();
                         off = ansi_normal();
                 } else if (u->state == UNIT_FILE_ENABLED) {
@@ -5741,8 +5741,8 @@ static int unit_is_enabled(int argc, char *argv[], void *userdata) {
                 STRV_FOREACH(name, names) {
                         UnitFileState state;
 
-                        state = unit_file_get_state(arg_scope, arg_root, *name);
-                        if (state < 0)
+                        r = unit_file_get_state(arg_scope, arg_root, *name, &state);
+                        if (r < 0)
                                 return log_error_errno(state, "Failed to get unit file state for %s: %m", *name);
 
                         if (IN_SET(state,

src/sysv-generator/sysv-generator.c

@@ -742,6 +742,7 @@ static int fix_order(SysvStub *s, Hashmap *all_services) {
 
 static int enumerate_sysv(const LookupPaths *lp, Hashmap *all_services) {
         char **path;
+        int r;
 
         assert(lp);
         assert(all_services);
@@ -761,7 +762,6 @@ static int enumerate_sysv(const LookupPaths *lp, Hashmap *all_services) {
                         _cleanup_free_ char *fpath = NULL, *name = NULL;
                         _cleanup_(free_sysvstubp) SysvStub *service = NULL;
                         struct stat st;
-                        int r;
 
                         if (fstatat(dirfd(d), de->d_name, &st, 0) < 0) {
                                 log_warning_errno(errno, "stat() failed on %s/%s, ignoring: %m", *path, de->d_name);
@@ -781,8 +781,12 @@ static int enumerate_sysv(const LookupPaths *lp, Hashmap *all_services) {
                         if (hashmap_contains(all_services, name))
                                 continue;
 
-                        if (unit_file_lookup_state(UNIT_FILE_SYSTEM, NULL, lp, name) >= 0) {
-                                log_debug("Native unit for %s already exists, skipping", name);
+                        r = unit_file_lookup_state(UNIT_FILE_SYSTEM, NULL, lp, name, NULL);
+                        if (r < 0 && r != -ENOENT) {
+                                log_debug_errno(r, "Failed to detect whether %s exists, skipping: %m", name);
+                                continue;
+                        } else if (r >= 0) {
+                                log_debug("Native unit for %s already exists, skipping.", name);
                                 continue;
                         }
 

src/test/test-install-root.c

@@ -0,0 +1,665 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2011 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "alloc-util.h"
+#include "fileio.h"
+#include "install.h"
+#include "mkdir.h"
+#include "rm-rf.h"
+#include "string-util.h"
+
+static void test_basic_mask_and_enable(const char *root) {
+        const char *p;
+        UnitFileState state;
+        UnitFileChange *changes = NULL;
+        unsigned n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "a.service", NULL) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "b.service", NULL) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "c.service", NULL) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "d.service", NULL) == -ENOENT);
+
+        p = strjoina(root, "/usr/lib/systemd/system/a.service");
+        assert_se(write_string_file(p,
+                                    "[Install]\n"
+                                    "WantedBy=multi-user.target\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "a.service", NULL) >= 0);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "a.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        p = strjoina(root, "/usr/lib/systemd/system/b.service");
+        assert_se(symlink("a.service", p) >= 0);
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "b.service", NULL) >= 0);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "b.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        p = strjoina(root, "/usr/lib/systemd/system/c.service");
+        assert_se(symlink("/usr/lib/systemd/system/a.service", p) >= 0);
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "c.service", NULL) >= 0);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "c.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        p = strjoina(root, "/usr/lib/systemd/system/d.service");
+        assert_se(symlink("c.service", p) >= 0);
+
+        /* This one is interesting, as d follows a relative, then an absolute symlink */
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "d.service", NULL) >= 0);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "d.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        assert_se(unit_file_mask(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("a.service"), false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/dev/null"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/a.service");
+        assert_se(streq(changes[0].path, p));
+
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "a.service", &state) >= 0 && state == UNIT_FILE_MASKED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "b.service", &state) >= 0 && state == UNIT_FILE_MASKED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "c.service", &state) >= 0 && state == UNIT_FILE_MASKED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "d.service", &state) >= 0 && state == UNIT_FILE_MASKED);
+
+        /* Enabling a masked unit should fail! */
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("a.service"), false, &changes, &n_changes) == -ESHUTDOWN);
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_unmask(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("a.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_UNLINK);
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/a.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("a.service"), false, &changes, &n_changes) == 1);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/usr/lib/systemd/system/a.service"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/a.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "a.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "b.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "c.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "d.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+
+        /* Enabling it again should succeed but be a NOP */
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("a.service"), false, &changes, &n_changes) == 1);
+        assert_se(n_changes == 0);
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_disable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("a.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_UNLINK);
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/a.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "a.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "b.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "c.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "d.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        /* Disabling a disabled unit must suceed but be a NOP */
+        assert_se(unit_file_disable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("a.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 0);
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        /* Let's enable this indirectly via a symlink */
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("d.service"), false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/usr/lib/systemd/system/a.service"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/a.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "a.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "b.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "c.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "d.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+
+        /* Let's try to reenable */
+
+        assert_se(unit_file_reenable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("b.service"), false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 2);
+        assert_se(changes[0].type == UNIT_FILE_UNLINK);
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/a.service");
+        assert_se(streq(changes[0].path, p));
+        assert_se(changes[1].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[1].source, "/usr/lib/systemd/system/a.service"));
+        assert_se(streq(changes[1].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "a.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "b.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "c.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "d.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+}
+
+static void test_linked_units(const char *root) {
+        const char *p, *q;
+        UnitFileState state;
+        UnitFileChange *changes = NULL;
+        unsigned n_changes = 0, i;
+
+        /*
+         * We'll test three cases here:
+         *
+         * a) a unit file in /opt, that we use "systemctl link" and
+         * "systemctl enable" on to make it available to the system
+         *
+         * b) a unit file in /opt, that is statically linked into
+         * /usr/lib/systemd/system, that "enable" should work on
+         * correctly.
+         *
+         * c) a unit file in /opt, that is linked into
+         * /etc/systemd/system, and where "enable" should result in
+         * -ELOOP, since using information from /etc to generate
+         * information in /etc should not be allowed.
+         */
+
+        p = strjoina(root, "/opt/linked.service");
+        assert_se(write_string_file(p,
+                                    "[Install]\n"
+                                    "WantedBy=multi-user.target\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        p = strjoina(root, "/opt/linked2.service");
+        assert_se(write_string_file(p,
+                                    "[Install]\n"
+                                    "WantedBy=multi-user.target\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        p = strjoina(root, "/opt/linked3.service");
+        assert_se(write_string_file(p,
+                                    "[Install]\n"
+                                    "WantedBy=multi-user.target\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "linked.service", NULL) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "linked2.service", NULL) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "linked3.service", NULL) == -ENOENT);
+
+        p = strjoina(root, "/usr/lib/systemd/system/linked2.service");
+        assert_se(symlink("/opt/linked2.service", p) >= 0);
+
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/linked3.service");
+        assert_se(symlink("/opt/linked3.service", p) >= 0);
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "linked.service", &state) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "linked2.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "linked3.service", &state) >= 0 && state == UNIT_FILE_LINKED);
+
+        /* First, let's link the unit into the search path */
+        assert_se(unit_file_link(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("/opt/linked.service"), false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/opt/linked.service"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/linked.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "linked.service", &state) >= 0 && state == UNIT_FILE_LINKED);
+
+        /* Let's unlink it from the search path again */
+        assert_se(unit_file_disable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("linked.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_UNLINK);
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/linked.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "linked.service", NULL) == -ENOENT);
+
+        /* Now, let's not just link it, but also enable it */
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("/opt/linked.service"), false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 2);
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/linked.service");
+        q = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/linked.service");
+        for (i = 0 ; i < n_changes; i++) {
+                assert_se(changes[i].type == UNIT_FILE_SYMLINK);
+                assert_se(streq(changes[i].source, "/opt/linked.service"));
+
+                if (p && streq(changes[i].path, p))
+                        p = NULL;
+                else if (q && streq(changes[i].path, q))
+                        q = NULL;
+                else
+                        assert_not_reached("wut?");
+        }
+        assert(!p && !q);
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "linked.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+
+        /* And let's unlink it again */
+        assert_se(unit_file_disable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("linked.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 2);
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/linked.service");
+        q = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/linked.service");
+        for (i = 0; i < n_changes; i++) {
+                assert_se(changes[i].type == UNIT_FILE_UNLINK);
+
+                if (p && streq(changes[i].path, p))
+                        p = NULL;
+                else if (q && streq(changes[i].path, q))
+                        q = NULL;
+                else
+                        assert_not_reached("wut?");
+        }
+        assert(!p && !q);
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "linked.service", NULL) == -ENOENT);
+
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("linked2.service"), false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 2);
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/linked2.service");
+        q = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/linked2.service");
+        for (i = 0 ; i < n_changes; i++) {
+                assert_se(changes[i].type == UNIT_FILE_SYMLINK);
+                assert_se(streq(changes[i].source, "/opt/linked2.service"));
+
+                if (p && streq(changes[i].path, p))
+                        p = NULL;
+                else if (q && streq(changes[i].path, q))
+                        q = NULL;
+                else
+                        assert_not_reached("wut?");
+        }
+        assert(!p && !q);
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("linked3.service"), false, &changes, &n_changes) == -ELOOP);
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+}
+
+static void test_default(const char *root) {
+        _cleanup_free_ char *def = NULL;
+        UnitFileChange *changes = NULL;
+        unsigned n_changes = 0;
+        const char *p;
+
+        p = strjoina(root, "/usr/lib/systemd/system/test-default-real.target");
+        assert_se(write_string_file(p, "# pretty much empty", WRITE_STRING_FILE_CREATE) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system/test-default.target");
+        assert_se(symlink("test-default-real.target", p) >= 0);
+
+        assert_se(unit_file_get_default(UNIT_FILE_SYSTEM, root, &def) == -ENOENT);
+
+        assert_se(unit_file_set_default(UNIT_FILE_SYSTEM, root, "idontexist.target", false, &changes, &n_changes) == -ENOENT);
+        assert_se(n_changes == 0);
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_default(UNIT_FILE_SYSTEM, root, &def) == -ENOENT);
+
+        assert_se(unit_file_set_default(UNIT_FILE_SYSTEM, root, "test-default.target", false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/usr/lib/systemd/system/test-default-real.target"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/default.target");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_default(UNIT_FILE_SYSTEM, root, &def) >= 0);
+        assert_se(streq_ptr(def, "test-default-real.target"));
+}
+
+static void test_add_dependency(const char *root) {
+        UnitFileChange *changes = NULL;
+        unsigned n_changes = 0;
+        const char *p;
+
+        p = strjoina(root, "/usr/lib/systemd/system/real-add-dependency-test-target.target");
+        assert_se(write_string_file(p, "# pretty much empty", WRITE_STRING_FILE_CREATE) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system/add-dependency-test-target.target");
+        assert_se(symlink("real-add-dependency-test-target.target", p) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system/real-add-dependency-test-service.service");
+        assert_se(write_string_file(p, "# pretty much empty", WRITE_STRING_FILE_CREATE) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system/add-dependency-test-service.service");
+        assert_se(symlink("real-add-dependency-test-service.service", p) >= 0);
+
+        assert_se(unit_file_add_dependency(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("add-dependency-test-service.service"), "add-dependency-test-target.target", UNIT_WANTS, false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/usr/lib/systemd/system/real-add-dependency-test-service.service"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/real-add-dependency-test-target.target.wants/real-add-dependency-test-service.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+}
+
+static void test_template_enable(const char *root) {
+        UnitFileChange *changes = NULL;
+        unsigned n_changes = 0;
+        UnitFileState state;
+        const char *p;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@.service", &state) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@def.service", &state) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@foo.service", &state) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@foo.service", &state) == -ENOENT);
+
+        p = strjoina(root, "/usr/lib/systemd/system/template@.service");
+        assert_se(write_string_file(p,
+                                    "[Install]\n"
+                                    "DefaultInstance=def\n"
+                                    "WantedBy=multi-user.target\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system/template-symlink@.service");
+        assert_se(symlink("template@.service", p) >= 0);
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@def.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@foo.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@def.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@foo.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("template@.service"), false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/usr/lib/systemd/system/template@.service"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/template@def.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@def.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@foo.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@def.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@foo.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        assert_se(unit_file_disable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("template@.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_UNLINK);
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@def.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@foo.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@def.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@foo.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("template@foo.service"), false, &changes, &n_changes) >= 0);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/usr/lib/systemd/system/template@.service"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/template@foo.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@def.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@foo.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@foo.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@def.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@foo.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+
+        assert_se(unit_file_disable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("template@foo.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_UNLINK);
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@def.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@foo.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@quux.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@def.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@foo.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@quux.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("template-symlink@quux.service"), false, &changes, &n_changes) >= 0);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/usr/lib/systemd/system/template@.service"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/template@quux.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@def.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@foo.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template@quux.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@def.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@foo.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "template-symlink@quux.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+}
+
+static void test_indirect(const char *root) {
+        UnitFileChange *changes = NULL;
+        unsigned n_changes = 0;
+        UnitFileState state;
+        const char *p;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "indirecta.service", &state) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "indirectb.service", &state) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "indirectc.service", &state) == -ENOENT);
+
+        p = strjoina(root, "/usr/lib/systemd/system/indirecta.service");
+        assert_se(write_string_file(p,
+                                    "[Install]\n"
+                                    "Also=indirectb.service\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system/indirectb.service");
+        assert_se(write_string_file(p,
+                                    "[Install]\n"
+                                    "WantedBy=multi-user.target\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system/indirectc.service");
+        assert_se(symlink("indirecta.service", p) >= 0);
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "indirecta.service", &state) >= 0 && state == UNIT_FILE_INDIRECT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "indirectb.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "indirectc.service", &state) >= 0 && state == UNIT_FILE_INDIRECT);
+
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("indirectc.service"), false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/usr/lib/systemd/system/indirectb.service"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/indirectb.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "indirecta.service", &state) >= 0 && state == UNIT_FILE_INDIRECT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "indirectb.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "indirectc.service", &state) >= 0 && state == UNIT_FILE_INDIRECT);
+
+        assert_se(unit_file_disable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("indirectc.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_UNLINK);
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/indirectb.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+}
+
+static void test_preset_and_list(const char *root) {
+        UnitFileChange *changes = NULL;
+        unsigned n_changes = 0, i;
+        const char *p, *q;
+        UnitFileState state;
+        bool got_yes = false, got_no = false;
+        Iterator j;
+        UnitFileList *fl;
+        Hashmap *h;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-yes.service", &state) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-no.service", &state) == -ENOENT);
+
+        p = strjoina(root, "/usr/lib/systemd/system/preset-yes.service");
+        assert_se(write_string_file(p,
+                                    "[Install]\n"
+                                    "WantedBy=multi-user.target\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system/preset-no.service");
+        assert_se(write_string_file(p,
+                                    "[Install]\n"
+                                    "WantedBy=multi-user.target\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system-preset/test.preset");
+        assert_se(write_string_file(p,
+                                    "enable *-yes.*\n"
+                                    "disable *\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-yes.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-no.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        assert_se(unit_file_preset(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("preset-yes.service"), UNIT_FILE_PRESET_FULL, false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_SYMLINK);
+        assert_se(streq(changes[0].source, "/usr/lib/systemd/system/preset-yes.service"));
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/preset-yes.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-yes.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-no.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        assert_se(unit_file_disable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("preset-yes.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_UNLINK);
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/preset-yes.service");
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-yes.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-no.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        assert_se(unit_file_preset(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("preset-no.service"), UNIT_FILE_PRESET_FULL, false, &changes, &n_changes) >= 0);
+        assert_se(n_changes == 0);
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-yes.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-no.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        assert_se(unit_file_preset_all(UNIT_FILE_SYSTEM, false, root, UNIT_FILE_PRESET_FULL, false, &changes, &n_changes) >= 0);
+
+        assert_se(n_changes > 0);
+
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/multi-user.target.wants/preset-yes.service");
+
+        for (i = 0; i < n_changes; i++) {
+
+                if (changes[i].type == UNIT_FILE_SYMLINK) {
+                        assert_se(streq(changes[i].source, "/usr/lib/systemd/system/preset-yes.service"));
+                        assert_se(streq(changes[i].path, p));
+                } else
+                        assert_se(changes[i].type == UNIT_FILE_UNLINK);
+        }
+
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-yes.service", &state) >= 0 && state == UNIT_FILE_ENABLED);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "preset-no.service", &state) >= 0 && state == UNIT_FILE_DISABLED);
+
+        assert_se(h = hashmap_new(&string_hash_ops));
+        assert_se(unit_file_get_list(UNIT_FILE_SYSTEM, root, h) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system/preset-yes.service");
+        q = strjoina(root, "/usr/lib/systemd/system/preset-no.service");
+
+        HASHMAP_FOREACH(fl, h, j) {
+                assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, basename(fl->path), &state) >= 0);
+                assert_se(fl->state == state);
+
+                if (streq(fl->path, p)) {
+                        got_yes = true;
+                        assert_se(fl->state == UNIT_FILE_ENABLED);
+                } else if (streq(fl->path, q)) {
+                        got_no = true;
+                        assert_se(fl->state == UNIT_FILE_DISABLED);
+                } else
+                        assert_se(IN_SET(fl->state, UNIT_FILE_DISABLED, UNIT_FILE_STATIC, UNIT_FILE_INDIRECT));
+        }
+
+        unit_file_list_free(h);
+
+        assert_se(got_yes && got_no);
+}
+
+int main(int argc, char *argv[]) {
+        char root[] = "/tmp/rootXXXXXX";
+        const char *p;
+
+        assert_se(mkdtemp(root));
+
+        p = strjoina(root, "/usr/lib/systemd/system/");
+        assert_se(mkdir_p(p, 0755) >= 0);
+
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/");
+        assert_se(mkdir_p(p, 0755) >= 0);
+
+        p = strjoina(root, "/run/systemd/system/");
+        assert_se(mkdir_p(p, 0755) >= 0);
+
+        p = strjoina(root, "/opt/");
+        assert_se(mkdir_p(p, 0755) >= 0);
+
+        p = strjoina(root, "/usr/lib/systemd/system-preset/");
+        assert_se(mkdir_p(p, 0755) >= 0);
+
+        test_basic_mask_and_enable(root);
+        test_linked_units(root);
+        test_default(root);
+        test_add_dependency(root);
+        test_template_enable(root);
+        test_indirect(root);
+        test_preset_and_list(root);
+
+        assert_se(rm_rf(root, REMOVE_ROOT|REMOVE_PHYSICAL) >= 0);
+
+        return 0;
+}

src/test/test-install.c

@@ -46,17 +46,19 @@ int main(int argc, char* argv[]) {
         const char *const files2[] = { "/home/lennart/test.service", NULL };
         UnitFileChange *changes = NULL;
         unsigned n_changes = 0;
+        UnitFileState state = 0;
 
         h = hashmap_new(&string_hash_ops);
         r = unit_file_get_list(UNIT_FILE_SYSTEM, NULL, h);
         assert_se(r == 0);
 
         HASHMAP_FOREACH(p, h, i) {
-                UnitFileState s;
+                UnitFileState s = _UNIT_FILE_STATE_INVALID;
 
-                s = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(p->path));
+                r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(p->path), &s);
 
-                assert_se(p->state == s);
+                assert_se((r < 0 && p->state == UNIT_FILE_BAD) ||
+                          (p->state == s));
 
                 fprintf(stderr, "%s (%s)\n",
                         p->path,
@@ -78,7 +80,9 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0]) == UNIT_FILE_ENABLED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0], &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_ENABLED);
 
         log_error("disable");
 
@@ -91,7 +95,9 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0]) == UNIT_FILE_DISABLED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0], &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_DISABLED);
 
         log_error("mask");
         changes = NULL;
@@ -106,7 +112,9 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0]) == UNIT_FILE_MASKED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0], &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_MASKED);
 
         log_error("unmask");
         changes = NULL;
@@ -121,7 +129,9 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0]) == UNIT_FILE_DISABLED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0], &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_DISABLED);
 
         log_error("mask");
         changes = NULL;
@@ -133,7 +143,9 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0]) == UNIT_FILE_MASKED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0], &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_MASKED);
 
         log_error("disable");
         changes = NULL;
@@ -148,7 +160,9 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0]) == UNIT_FILE_MASKED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0], &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_MASKED);
 
         log_error("umask");
         changes = NULL;
@@ -160,7 +174,9 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0]) == UNIT_FILE_DISABLED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, files[0], &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_DISABLED);
 
         log_error("enable files2");
         changes = NULL;
@@ -172,19 +188,22 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0])) == UNIT_FILE_ENABLED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0]), &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_ENABLED);
 
         log_error("disable files2");
         changes = NULL;
         n_changes = 0;
 
-        r = unit_file_disable(UNIT_FILE_SYSTEM, false, NULL, (char**) files2, &changes, &n_changes);
+        r = unit_file_disable(UNIT_FILE_SYSTEM, false, NULL, STRV_MAKE(basename(files2[0])), &changes, &n_changes);
         assert_se(r >= 0);
 
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0])) == _UNIT_FILE_STATE_INVALID);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0]), &state);
+        assert_se(r < 0);
 
         log_error("link files2");
         changes = NULL;
@@ -196,19 +215,22 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0])) == UNIT_FILE_LINKED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0]), &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_LINKED);
 
         log_error("disable files2");
         changes = NULL;
         n_changes = 0;
 
-        r = unit_file_disable(UNIT_FILE_SYSTEM, false, NULL, (char**) files2, &changes, &n_changes);
+        r = unit_file_disable(UNIT_FILE_SYSTEM, false, NULL, STRV_MAKE(basename(files2[0])), &changes, &n_changes);
         assert_se(r >= 0);
 
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0])) == _UNIT_FILE_STATE_INVALID);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0]), &state);
+        assert_se(r < 0);
 
         log_error("link files2");
         changes = NULL;
@@ -220,7 +242,9 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0])) == UNIT_FILE_LINKED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0]), &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_LINKED);
 
         log_error("reenable files2");
         changes = NULL;
@@ -232,19 +256,22 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0])) == UNIT_FILE_ENABLED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0]), &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_ENABLED);
 
         log_error("disable files2");
         changes = NULL;
         n_changes = 0;
 
-        r = unit_file_disable(UNIT_FILE_SYSTEM, false, NULL, (char**) files2, &changes, &n_changes);
+        r = unit_file_disable(UNIT_FILE_SYSTEM, false, NULL, STRV_MAKE(basename(files2[0])), &changes, &n_changes);
         assert_se(r >= 0);
 
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0])) == _UNIT_FILE_STATE_INVALID);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files2[0]), &state);
+        assert_se(r < 0);
         log_error("preset files");
         changes = NULL;
         n_changes = 0;
@@ -255,7 +282,9 @@ int main(int argc, char* argv[]) {
         dump_changes(changes, n_changes);
         unit_file_changes_free(changes, n_changes);
 
-        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files[0])) == UNIT_FILE_ENABLED);
+        r = unit_file_get_state(UNIT_FILE_SYSTEM, NULL, basename(files[0]), &state);
+        assert_se(r >= 0);
+        assert_se(state == UNIT_FILE_ENABLED);
 
         return 0;
 }