chiark / gitweb /
journal: store XOR combination of entry data object hashes to identify hash lines
[elogind.git] / src / install.c
index 2c57c9b607510b9207733188bd579f99e9cc0e3e..cfbd50ead954c93e518f19d05be6ef7f6402f5fe 100644 (file)
@@ -1,9 +1,9 @@
-/*-*- Mode: C; c-basic-offset: 8 -*-*/
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
 
 /***
   This file is part of systemd.
 
 
 /***
   This file is part of systemd.
 
-  Copyright 2010 Lennart Poettering
+  Copyright 2011 Lennart Poettering
 
   systemd is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by
 
   systemd is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by
@@ -11,7 +11,7 @@
   (at your option) any later version.
 
   systemd is distributed in the hope that it will be useful, but
   (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
+  WITHOUT ANY WARRANTY; without even the implied warranty <of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   General Public License for more details.
 
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   General Public License for more details.
 
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#include <sys/stat.h>
-#include <stdio.h>
-#include <getopt.h>
 #include <errno.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <unistd.h>
 #include <unistd.h>
+#include <string.h>
+#include <fnmatch.h>
 
 
-#include "log.h"
-#include "path-lookup.h"
 #include "util.h"
 #include "util.h"
-#include "macro.h"
+#include "hashmap.h"
+#include "set.h"
+#include "path-lookup.h"
 #include "strv.h"
 #include "strv.h"
+#include "unit-name.h"
+#include "install.h"
 #include "conf-parser.h"
 #include "conf-parser.h"
-#include "dbus-common.h"
-#include "sd-daemon.h"
-
-static bool arg_force = false;
-
-static enum {
-        WHERE_SYSTEM,
-        WHERE_SESSION,
-        WHERE_GLOBAL,
-} arg_where = WHERE_SYSTEM;
-
-static enum {
-        ACTION_INVALID,
-        ACTION_ENABLE,
-        ACTION_DISABLE,
-        ACTION_TEST
-} arg_action = ACTION_INVALID;
-
-static enum {
-        REALIZE_NO,        /* Don't reload/start/stop or anything */
-        REALIZE_RELOAD,    /* Only reload daemon config, don't stop/start */
-        REALIZE_MINIMAL,   /* Only shutdown/restart if running. */
-        REALIZE_MAYBE,     /* Start if WantedBy= suggests */
-        REALIZE_YES        /* Start unconditionally */
-} arg_realize = REALIZE_NO;
 
 typedef struct {
         char *name;
 
 typedef struct {
         char *name;
@@ -65,842 +42,1913 @@ typedef struct {
         char **wanted_by;
 } InstallInfo;
 
         char **wanted_by;
 } InstallInfo;
 
-Hashmap *will_install = NULL, *have_installed = NULL;
-
-static int help(void) {
-
-        printf("%s [OPTIONS...] {COMMAND} ...\n\n"
-               "Install init system units.\n\n"
-               "  -h --help           Show this help\n"
-               "     --force          Override existing links\n"
-               "     --system         Install into system\n"
-               "     --session        Install into session\n"
-               "     --global         Install into all sessions\n"
-               "     --realize[=MODE] Start/stop/restart unit after installation\n"
-               "                      Takes 'no', 'minimal', 'maybe' or 'yes'\n\n"
-               "Commands:\n"
-               "  enable [NAME...]    Enable one or more units\n"
-               "  disable [NAME...]   Disable one or more units\n"
-               "  test [NAME...]      Test whether any of the specified units are enabled\n",
-               program_invocation_short_name);
-
-        return 0;
-}
-
-static int parse_argv(int argc, char *argv[]) {
+typedef struct {
+        Hashmap *will_install;
+        Hashmap *have_installed;
+} InstallContext;
 
 
-        enum {
-                ARG_SESSION = 0x100,
-                ARG_SYSTEM,
-                ARG_GLOBAL,
-                ARG_FORCE,
-                ARG_REALIZE
-        };
+static int lookup_paths_init_from_scope(LookupPaths *paths, UnitFileScope scope) {
+        assert(paths);
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
 
 
-        static const struct option options[] = {
-                { "help",      no_argument,       NULL, 'h'         },
-                { "session",   no_argument,       NULL, ARG_SESSION },
-                { "system",    no_argument,       NULL, ARG_SYSTEM  },
-                { "global",    no_argument,       NULL, ARG_GLOBAL  },
-                { "force",     no_argument,       NULL, ARG_FORCE   },
-                { "realize",   optional_argument, NULL, ARG_REALIZE },
-                { NULL,        0,                 NULL, 0           }
-        };
+        zero(*paths);
 
 
-        int c;
+        return lookup_paths_init(paths,
+                                 scope == UNIT_FILE_SYSTEM ? MANAGER_SYSTEM : MANAGER_USER,
+                                 scope == UNIT_FILE_USER);
+}
 
 
-        assert(argc >= 1);
-        assert(argv);
+static int get_config_path(UnitFileScope scope, bool runtime, const char *root_dir, char **ret) {
+        char *p = NULL;
+        int r;
 
 
-        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
+        assert(ret);
 
 
-                switch (c) {
+        switch (scope) {
 
 
-                case 'h':
-                        help();
-                        return 0;
+        case UNIT_FILE_SYSTEM:
 
 
-                case ARG_SESSION:
-                        arg_where = WHERE_SESSION;
-                        break;
+                if (root_dir && runtime)
+                        return -EINVAL;
 
 
-                case ARG_SYSTEM:
-                        arg_where = WHERE_SYSTEM;
-                        break;
+                if (runtime)
+                        p = strdup("/run/systemd/system");
+                else if (root_dir)
+                        asprintf(&p, "%s/%s", root_dir, SYSTEM_CONFIG_UNIT_PATH);
+                else
+                        p = strdup(SYSTEM_CONFIG_UNIT_PATH);
 
 
-                case ARG_GLOBAL:
-                        arg_where = WHERE_GLOBAL;
-                        break;
+                break;
 
 
-                case ARG_FORCE:
-                        arg_force = true;
-                        break;
+        case UNIT_FILE_GLOBAL:
 
 
-                case ARG_REALIZE:
-
-                        if (!optarg)
-                                arg_realize = REALIZE_MAYBE;
-                        else if (streq(optarg, "no"))
-                                arg_realize = REALIZE_NO;
-                        else if (streq(optarg, "minimal"))
-                                arg_realize = REALIZE_MINIMAL;
-                        else if (streq(optarg, "maybe"))
-                                arg_realize = REALIZE_MAYBE;
-                        else if (streq(optarg, "yes"))
-                                arg_realize = REALIZE_YES;
-                        else if (streq(optarg, "reload"))
-                                arg_realize = REALIZE_RELOAD;
-                        else {
-                                log_error("Invalid --realize argument %s", optarg);
-                                return -EINVAL;
-                        }
+                if (root_dir)
+                        return -EINVAL;
 
 
-                        break;
+                if (runtime)
+                        p = strdup("/run/systemd/user");
+                else
+                        p = strdup(USER_CONFIG_UNIT_PATH);
+                break;
 
 
-                case '?':
-                        return -EINVAL;
+        case UNIT_FILE_USER:
 
 
-                default:
-                        log_error("Unknown option code %c", c);
+                if (root_dir || runtime)
                         return -EINVAL;
                         return -EINVAL;
-                }
-        }
-
-        if (optind >= argc) {
-                help();
-                return -EINVAL;
-        }
 
 
-        if (streq(argv[optind], "enable"))
-                arg_action = ACTION_ENABLE;
-        else if (streq(argv[optind], "disable"))
-                arg_action = ACTION_DISABLE;
-        else if (streq(argv[optind], "test"))
-                arg_action = ACTION_TEST;
-        else {
-                log_error("Unknown verb %s.", argv[optind]);
-                return -EINVAL;
-        }
+                r = user_config_home(&p);
+                if (r <= 0)
+                        return r < 0 ? r : -ENOENT;
 
 
-        optind++;
+                break;
 
 
-        if (optind >= argc) {
-                log_error("Missing unit name.");
-                return -EINVAL;
+        default:
+                assert_not_reached("Bad scope");
         }
 
         }
 
+        if (!p)
+                return -ENOMEM;
 
 
-        return 1;
+        *ret = p;
+        return 0;
 }
 
 }
 
-static void install_info_free(InstallInfo *i) {
-        assert(i);
-
-        free(i->name);
-        free(i->path);
-        strv_free(i->aliases);
-        strv_free(i->wanted_by);
-        free(i);
-}
+static int add_file_change(
+                UnitFileChange **changes,
+                unsigned *n_changes,
+                UnitFileChangeType type,
+                const char *path,
+                const char *source) {
 
 
-static void install_info_hashmap_free(Hashmap *m) {
-        InstallInfo *i;
+        UnitFileChange *c;
+        unsigned i;
 
 
-        while ((i = hashmap_steal_first(m)))
-                install_info_free(i);
+        assert(path);
+        assert(!changes == !n_changes);
 
 
-        hashmap_free(m);
-}
+        if (!changes)
+                return 0;
 
 
-static bool unit_name_valid(const char *name) {
+        c = realloc(*changes, (*n_changes + 1) * sizeof(UnitFileChange));
+        if (!c)
+                return -ENOMEM;
 
 
-        /* This is a minimal version of unit_name_valid() from
-         * unit-name.c */
+        *changes = c;
+        i = *n_changes;
 
 
-        if (!*name)
-                return false;
+        c[i].type = type;
+        c[i].path = strdup(path);
+        if (!c[i].path)
+                return -ENOMEM;
 
 
-        if (ignore_file(name))
-                return false;
+        if (source) {
+                c[i].source = strdup(source);
+                if (!c[i].source) {
+                        free(c[i].path);
+                        return -ENOMEM;
+                }
+        } else
+                c[i].source = NULL;
 
 
-        return true;
+        *n_changes = i+1;
+        return 0;
 }
 
 }
 
-static int install_info_add(const char *name) {
-        InstallInfo *i;
+static int mark_symlink_for_removal(
+                Set **remove_symlinks_to,
+                const char *p) {
+
+        char *n;
         int r;
 
         int r;
 
-        if (!unit_name_valid(name))
-                return -EINVAL;
+        assert(p);
 
 
-        if (hashmap_get(have_installed, name) ||
-            hashmap_get(will_install, name))
-                return 0;
+        r = set_ensure_allocated(remove_symlinks_to, string_hash_func, string_compare_func);
+        if (r < 0)
+                return r;
 
 
-        if (!(i = new0(InstallInfo, 1))) {
-                r = -ENOMEM;
-                goto fail;
-        }
+        n = strdup(p);
+        if (!n)
+                return -ENOMEM;
 
 
-        if (!(i->name = strdup(name))) {
-                r = -ENOMEM;
-                goto fail;
-        }
+        path_kill_slashes(n);
 
 
-        if ((r = hashmap_put(will_install, i->name, i)) < 0)
-                goto fail;
+        r = set_put(*remove_symlinks_to, n);
+        if (r < 0) {
+                free(n);
+                return r == -EEXIST ? 0 : r;
+        }
 
         return 0;
 
         return 0;
-
-fail:
-        if (i)
-                install_info_free(i);
-
-        return r;
 }
 
 }
 
-static int daemon_reload(DBusConnection *bus) {
-        DBusMessage *m = NULL, *reply = NULL;
-        DBusError error;
-        int r;
-
-        assert(bus);
-
-        dbus_error_init(&error);
-
-        if (!(m = dbus_message_new_method_call(
-                              "org.freedesktop.systemd1",
-                              "/org/freedesktop/systemd1",
-                              "org.freedesktop.systemd1.Manager",
-                              "Reload"))) {
-                log_error("Could not allocate message.");
-                return -ENOMEM;
+static int remove_marked_symlinks_fd(
+                Set *remove_symlinks_to,
+                int fd,
+                const char *path,
+                const char *config_path,
+                bool *deleted,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        int r = 0;
+        DIR *d;
+        struct dirent buffer, *de;
+
+        assert(remove_symlinks_to);
+        assert(fd >= 0);
+        assert(path);
+        assert(config_path);
+        assert(deleted);
+
+        d = fdopendir(fd);
+        if (!d) {
+                close_nointr_nofail(fd);
+                return -errno;
         }
 
         }
 
-        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
-                log_error("Failed to reload configuration: %s", error.message);
-                r = -EIO;
-                goto finish;
-        }
+        rewinddir(d);
 
 
-        r = 0;
+        for (;;) {
+                int k;
 
 
-finish:
-        if (m)
-                dbus_message_unref(m);
+                k = readdir_r(d, &buffer, &de);
+                if (k != 0) {
+                        r = -errno;
+                        break;
+                }
 
 
-        if (reply)
-                dbus_message_unref(reply);
+                if (!de)
+                        break;
 
 
-        dbus_error_free(&error);
+                if (ignore_file(de->d_name))
+                        continue;
 
 
-        return r;
-}
+                dirent_ensure_type(d, de);
 
 
-static int install_info_run(DBusConnection *bus, InstallInfo *i) {
-        DBusMessage *m = NULL, *reply = NULL;
-        DBusError error;
-        int r;
-        const char *mode = "replace";
+                if (de->d_type == DT_DIR) {
+                        int nfd, q;
+                        char *p;
 
 
-        assert(bus);
-        assert(i);
+                        nfd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW);
+                        if (nfd < 0) {
+                                if (errno == ENOENT)
+                                        continue;
 
 
-        dbus_error_init(&error);
+                                if (r == 0)
+                                        r = -errno;
+                                continue;
+                        }
 
 
-        if (arg_action == ACTION_ENABLE) {
+                        p = path_make_absolute(de->d_name, path);
+                        if (!p) {
+                                close_nointr_nofail(nfd);
+                                r = -ENOMEM;
+                                break;
+                        }
 
 
-                if (arg_realize == REALIZE_MAYBE) {
-                        char **k;
-                        bool yes_please = false;
+                        /* This will close nfd, regardless whether it succeeds or not */
+                        q = remove_marked_symlinks_fd(remove_symlinks_to, nfd, p, config_path, deleted, changes, n_changes);
+                        free(p);
 
 
-                        STRV_FOREACH(k, i->wanted_by) {
-                                DBusMessageIter sub, iter;
+                        if (r == 0)
+                                r = q;
 
 
-                                const char *path, *state;
-                                const char *interface = "org.freedesktop.systemd1.Unit";
-                                const char *property = "ActiveState";
+                } else if (de->d_type == DT_LNK) {
+                        char *p, *dest;
+                        int q;
+                        bool found;
 
 
-                                if (!(m = dbus_message_new_method_call(
-                                                      "org.freedesktop.systemd1",
-                                                      "/org/freedesktop/systemd1",
-                                                      "org.freedesktop.systemd1.Manager",
-                                                      "GetUnit"))) {
-                                        log_error("Could not allocate message.");
-                                        r = -ENOMEM;
-                                        goto finish;
-                                }
+                        p = path_make_absolute(de->d_name, path);
+                        if (!p) {
+                                r = -ENOMEM;
+                                break;
+                        }
 
 
-                                if (!dbus_message_append_args(m,
-                                                              DBUS_TYPE_STRING, k,
-                                                              DBUS_TYPE_INVALID)) {
-                                        log_error("Could not append arguments to message.");
-                                        r = -ENOMEM;
-                                        goto finish;
-                                }
+                        q = readlink_and_canonicalize(p, &dest);
+                        if (q < 0) {
+                                free(p);
 
 
-                                if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
-                                        /* Hmm, this unit doesn't exist, let's try the next one */
-                                        dbus_message_unref(m);
-                                        m = NULL;
+                                if (q == -ENOENT)
                                         continue;
                                         continue;
-                                }
-
-                                if (!dbus_message_get_args(reply, &error,
-                                                           DBUS_TYPE_OBJECT_PATH, &path,
-                                                           DBUS_TYPE_INVALID)) {
-                                        log_error("Failed to parse reply: %s", error.message);
-                                        r = -EIO;
-                                        goto finish;
-                                }
-
-                                dbus_message_unref(m);
-                                if (!(m = dbus_message_new_method_call(
-                                                      "org.freedesktop.systemd1",
-                                                      path,
-                                                      "org.freedesktop.DBus.Properties",
-                                                      "Get"))) {
-                                        log_error("Could not allocate message.");
-                                        r = -ENOMEM;
-                                        goto finish;
-                                }
 
 
-                                if (!dbus_message_append_args(m,
-                                                              DBUS_TYPE_STRING, &interface,
-                                                              DBUS_TYPE_STRING, &property,
-                                                              DBUS_TYPE_INVALID)) {
-                                        log_error("Could not append arguments to message.");
-                                        r = -ENOMEM;
-                                        goto finish;
-                                }
+                                if (r == 0)
+                                        r = q;
+                                continue;
+                        }
 
 
-                                dbus_message_unref(reply);
-                                if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
-                                        log_error("Failed to issue method call: %s", error.message);
-                                        r = -EIO;
-                                        goto finish;
-                                }
+                        found =
+                                set_get(remove_symlinks_to, dest) ||
+                                set_get(remove_symlinks_to, file_name_from_path(dest));
 
 
-                                if (!dbus_message_iter_init(reply, &iter) ||
-                                    dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_VARIANT)  {
-                                        log_error("Failed to parse reply.");
-                                        r = -EIO;
-                                        goto finish;
-                                }
+                        if (found) {
 
 
-                                dbus_message_iter_recurse(&iter, &sub);
+                                if (unlink(p) < 0 && errno != ENOENT) {
 
 
-                                if (dbus_message_iter_get_arg_type(&sub) != DBUS_TYPE_STRING)  {
-                                        log_error("Failed to parse reply.");
-                                        r = -EIO;
-                                        goto finish;
-                                }
+                                        if (r == 0)
+                                                r = -errno;
+                                } else {
+                                        rmdir_parents(p, config_path);
+                                        path_kill_slashes(p);
 
 
-                                dbus_message_iter_get_basic(&sub, &state);
+                                        add_file_change(changes, n_changes, UNIT_FILE_UNLINK, p, NULL);
 
 
-                                dbus_message_unref(m);
-                                dbus_message_unref(reply);
-                                m = reply = NULL;
+                                        if (!set_get(remove_symlinks_to, p)) {
 
 
-                                if (streq(state, "active") ||
-                                    startswith(state, "reloading") ||
-                                    startswith(state, "activating")) {
-                                        yes_please = true;
-                                        break;
+                                                q = mark_symlink_for_removal(&remove_symlinks_to, p);
+                                                if (q < 0) {
+                                                        if (r == 0)
+                                                                r = q;
+                                                } else
+                                                        *deleted = true;
+                                        }
                                 }
                         }
 
                                 }
                         }
 
-                        if (!yes_please) {
-                                r = 0;
-                                goto finish;
-                        }
+                        free(p);
+                        free(dest);
                 }
                 }
+        }
 
 
-                if (!(m = dbus_message_new_method_call(
-                                      "org.freedesktop.systemd1",
-                                      "/org/freedesktop/systemd1",
-                                      "org.freedesktop.systemd1.Manager",
-                                      arg_realize == REALIZE_MINIMAL ? "TryRestartUnit" : "RestartUnit"))) {
-                        log_error("Could not allocate message.");
-                        r = -ENOMEM;
-                        goto finish;
-                }
+        closedir(d);
 
 
-                if (!dbus_message_append_args(m,
-                                              DBUS_TYPE_STRING, &i->name,
-                                              DBUS_TYPE_STRING, &mode,
-                                              DBUS_TYPE_INVALID)) {
-                        log_error("Could not append arguments to message.");
-                        r = -ENOMEM;
-                        goto finish;
-                }
+        return r;
+}
 
 
+static int remove_marked_symlinks(
+                Set *remove_symlinks_to,
+                const char *config_path,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
 
 
-        } else if (arg_action == ACTION_DISABLE) {
+        int fd, r = 0;
+        bool deleted;
 
 
-                if (!(m = dbus_message_new_method_call(
-                                      "org.freedesktop.systemd1",
-                                      "/org/freedesktop/systemd1",
-                                      "org.freedesktop.systemd1.Manager",
-                                      "StopUnit"))) {
-                        log_error("Could not allocate message.");
-                        r = -ENOMEM;
-                        goto finish;
-                }
+        assert(config_path);
 
 
-                if (!dbus_message_append_args(m,
-                                              DBUS_TYPE_STRING, &i->name,
-                                              DBUS_TYPE_STRING, &mode,
-                                              DBUS_TYPE_INVALID)) {
-                        log_error("Could not append arguments to message.");
-                        r = -ENOMEM;
-                        goto finish;
-                }
-        }
+        if (set_size(remove_symlinks_to) <= 0)
+                return 0;
 
 
-        if (!(reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error))) {
-                log_error("Failed to reload configuration: %s", error.message);
-                r = -EIO;
-                goto finish;
-        }
+        fd = open(config_path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW);
+        if (fd < 0)
+                return -errno;
 
 
-        r = 0;
+        do {
+                int q, cfd;
+                deleted = false;
 
 
-finish:
-        if (m)
-                dbus_message_unref(m);
+                cfd = dup(fd);
+                if (cfd < 0) {
+                        r = -errno;
+                        break;
+                }
 
 
-        if (reply)
-                dbus_message_unref(reply);
+                /* This takes possession of cfd and closes it */
+                q = remove_marked_symlinks_fd(remove_symlinks_to, cfd, config_path, config_path, &deleted, changes, n_changes);
+                if (r == 0)
+                        r = q;
+        } while (deleted);
 
 
-        dbus_error_free(&error);
+        close_nointr_nofail(fd);
 
         return r;
 }
 
 
         return r;
 }
 
-static int config_parse_also(
-                const char *filename,
-                unsigned line,
-                const char *section,
-                const char *lvalue,
-                const char *rvalue,
-                void *data,
-                void *userdata) {
-
-        char *w;
-        size_t l;
-        char *state;
+static int find_symlinks_fd(
+                const char *name,
+                int fd,
+                const char *path,
+                const char *config_path,
+                bool *same_name_link) {
+
+        int r = 0;
+        DIR *d;
+        struct dirent buffer, *de;
+
+        assert(name);
+        assert(fd >= 0);
+        assert(path);
+        assert(config_path);
+        assert(same_name_link);
+
+        d = fdopendir(fd);
+        if (!d) {
+                close_nointr_nofail(fd);
+                return -errno;
+        }
 
 
-        assert(filename);
-        assert(lvalue);
-        assert(rvalue);
+        for (;;) {
+                int k;
 
 
-        FOREACH_WORD_QUOTED(w, l, rvalue, state) {
-                char *n;
-                int r;
+                k = readdir_r(d, &buffer, &de);
+                if (k != 0) {
+                        r = -errno;
+                        break;
+                }
 
 
-                if (!(n = strndup(w, l)))
-                        return -ENOMEM;
+                if (!de)
+                        break;
 
 
-                r = install_info_add(n);
-                free(n);
+                if (ignore_file(de->d_name))
+                        continue;
 
 
-                if (r < 0)
-                        return r;
-        }
+                dirent_ensure_type(d, de);
 
 
-        return 0;
-}
+                if (de->d_type == DT_DIR) {
+                        int nfd, q;
+                        char *p;
 
 
-static int create_symlink(const char *old_path, const char *new_path) {
-        int r;
+                        nfd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW);
+                        if (nfd < 0) {
+                                if (errno == ENOENT)
+                                        continue;
 
 
-        assert(old_path);
-        assert(new_path);
+                                if (r == 0)
+                                        r = -errno;
+                                continue;
+                        }
 
 
-        if (arg_action == ACTION_ENABLE) {
-                char *dest;
+                        p = path_make_absolute(de->d_name, path);
+                        if (!p) {
+                                close_nointr_nofail(nfd);
+                                r = -ENOMEM;
+                                break;
+                        }
 
 
-                mkdir_parents(new_path, 0755);
+                        /* This will close nfd, regardless whether it succeeds or not */
+                        q = find_symlinks_fd(name, nfd, p, config_path, same_name_link);
+                        free(p);
 
 
-                if (symlink(old_path, new_path) >= 0)
-                        return 0;
+                        if (q > 0) {
+                                r = 1;
+                                break;
+                        }
 
 
-                if (errno != EEXIST) {
-                        log_error("Cannot link %s to %s: %m", old_path, new_path);
-                        return -errno;
-                }
+                        if (r == 0)
+                                r = q;
 
 
-                if ((r = readlink_and_make_absolute(new_path, &dest)) < 0) {
+                } else if (de->d_type == DT_LNK) {
+                        char *p, *dest;
+                        bool found_path, found_dest, b = false;
+                        int q;
 
 
-                        if (errno == EINVAL) {
-                                log_error("Cannot link %s to %s, file exists already and is not a symlink.", old_path, new_path);
-                                return -EEXIST;
+                        /* Acquire symlink name */
+                        p = path_make_absolute(de->d_name, path);
+                        if (!p) {
+                                r = -ENOMEM;
+                                break;
                         }
 
                         }
 
-                        log_error("readlink() failed: %s", strerror(-r));
-                        return r;
-                }
+                        /* Acquire symlink destination */
+                        q = readlink_and_canonicalize(p, &dest);
+                        if (q < 0) {
+                                free(p);
 
 
-                if (streq(dest, old_path)) {
-                        free(dest);
-                        return 0;
-                }
+                                if (q == -ENOENT)
+                                        continue;
 
 
-                if (!arg_force) {
-                        log_error("Cannot link %s to %s, symlink exists already and points to %s.", old_path, new_path, dest);
-                        free(dest);
-                        return -EEXIST;
-                }
+                                if (r == 0)
+                                        r = q;
+                                continue;
+                        }
 
 
-                free(dest);
-                unlink(new_path);
+                        /* Check if the symlink itself matches what we
+                         * are looking for */
+                        if (path_is_absolute(name))
+                                found_path = path_equal(p, name);
+                        else
+                                found_path = streq(de->d_name, name);
 
 
-                if (symlink(old_path, new_path) >= 0)
-                        return 0;
+                        /* Check if what the symlink points to
+                         * matches what we are looking for */
+                        if (path_is_absolute(name))
+                                found_dest = path_equal(dest, name);
+                        else
+                                found_dest = streq(file_name_from_path(dest), name);
 
 
-                log_error("Cannot link %s to %s: %m", old_path, new_path);
-                return -errno;
+                        free(dest);
 
 
-        } else if (arg_action == ACTION_DISABLE) {
-                char *dest;
+                        if (found_path && found_dest) {
+                                char *t;
 
 
-                if ((r = readlink_and_make_absolute(new_path, &dest)) < 0) {
-                        if (errno == ENOENT)
-                                return 0;
+                                /* Filter out same name links in the main
+                                 * config path */
+                                t = path_make_absolute(name, config_path);
+                                if (!t) {
+                                        free(p);
+                                        r = -ENOMEM;
+                                        break;
+                                }
 
 
-                        if (errno == EINVAL) {
-                                log_warning("File %s not a symlink, ignoring.", old_path);
-                                return 0;
+                                b = path_equal(t, p);
+                                free(t);
                         }
 
                         }
 
-                        log_error("readlink() failed: %s", strerror(-r));
-                        return r;
-                }
+                        free(p);
 
 
-                if (!streq(dest, old_path)) {
-                        log_warning("File %s not a symlink to %s but points to %s, ignoring.", new_path, old_path, dest);
-                        free(dest);
-                        return 0;
+                        if (b)
+                                *same_name_link = true;
+                        else if (found_path || found_dest) {
+                                r = 1;
+                                break;
+                        }
                 }
                 }
+        }
 
 
-                free(dest);
-                if (unlink(new_path) >= 0)
-                        return 0;
+        closedir(d);
+
+        return r;
+}
+
+static int find_symlinks(
+                const char *name,
+                const char *config_path,
+                bool *same_name_link) {
+
+        int fd;
 
 
-                log_error("Cannot unlink %s: %m", new_path);
+        assert(name);
+        assert(config_path);
+        assert(same_name_link);
+
+        fd = open(config_path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW);
+        if (fd < 0)
                 return -errno;
 
                 return -errno;
 
-        } else if (arg_action == ACTION_TEST) {
-                char *dest;
+        /* This takes possession of fd and closes it */
+        return find_symlinks_fd(name, fd, config_path, config_path, same_name_link);
+}
+
+static int find_symlinks_in_scope(
+                UnitFileScope scope,
+                const char *root_dir,
+                const char *name,
+                UnitFileState *state) {
+
+        int r;
+        char *path;
+        bool same_name_link_runtime = false, same_name_link = false;
 
 
-                if ((r = readlink_and_make_absolute(new_path, &dest)) < 0) {
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
+        assert(name);
 
 
-                        if (errno == ENOENT || errno == EINVAL)
-                                return 0;
+        if (scope == UNIT_FILE_SYSTEM || scope == UNIT_FILE_GLOBAL) {
 
 
-                        log_error("readlink() failed: %s", strerror(-r));
+                /* First look in runtime config path */
+                r = get_config_path(scope, true, root_dir, &path);
+                if (r < 0)
                         return r;
                         return r;
-                }
 
 
-                if (streq(dest, old_path)) {
-                        free(dest);
-                        return 1;
+                r = find_symlinks(name, path, &same_name_link_runtime);
+                free(path);
+
+                if (r < 0)
+                        return r;
+                else if (r > 0) {
+                        *state = UNIT_FILE_ENABLED_RUNTIME;
+                        return r;
                 }
                 }
+        }
 
 
-                return 0;
+        /* Then look in the normal config path */
+        r = get_config_path(scope, false, root_dir, &path);
+        if (r < 0)
+                return r;
+
+        r = find_symlinks(name, path, &same_name_link);
+        free(path);
+
+        if (r < 0)
+                return r;
+        else if (r > 0) {
+                *state = UNIT_FILE_ENABLED;
+                return r;
         }
 
         }
 
-        assert_not_reached("Unknown action.");
+        /* Hmm, we didn't find it, but maybe we found the same name
+         * link? */
+        if (same_name_link_runtime) {
+                *state = UNIT_FILE_LINKED_RUNTIME;
+                return 1;
+        } else if (same_name_link) {
+                *state = UNIT_FILE_LINKED;
+                return 1;
+        }
+
+        return 0;
 }
 
 }
 
-static int install_info_symlink_alias(InstallInfo *i, const char *config_path) {
-        char **s;
-        char *alias_path = NULL;
+int unit_file_mask(
+                UnitFileScope scope,
+                bool runtime,
+                const char *root_dir,
+                char *files[],
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        char **i, *prefix;
         int r;
 
         int r;
 
-        assert(i);
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
 
 
-        STRV_FOREACH(s, i->aliases) {
+        r = get_config_path(scope, runtime, root_dir, &prefix);
+        if (r < 0)
+                return r;
 
 
-                if (!unit_name_valid(*s)) {
-                        log_error("Invalid name %s.", *s);
-                        r = -EINVAL;
-                        goto finish;
+        STRV_FOREACH(i, files) {
+                char *path;
+
+                if (!unit_name_is_valid_no_type(*i, true)) {
+                        if (r == 0)
+                                r = -EINVAL;
+                        continue;
                 }
 
                 }
 
-                free(alias_path);
-                if (!(alias_path = path_make_absolute(*s, config_path))) {
-                        log_error("Out of memory");
+                path = path_make_absolute(*i, prefix);
+                if (!path) {
                         r = -ENOMEM;
                         r = -ENOMEM;
-                        goto finish;
+                        break;
                 }
 
                 }
 
-                if ((r = create_symlink(i->path, alias_path)) != 0)
-                        goto finish;
+                if (symlink("/dev/null", path) >= 0) {
+                        add_file_change(changes, n_changes, UNIT_FILE_SYMLINK, path, "/dev/null");
 
 
-                if (arg_action == ACTION_DISABLE)
-                        rmdir_parents(alias_path, config_path);
-        }
+                        free(path);
+                        continue;
+                }
 
 
-        r = 0;
+                if (errno == EEXIST) {
 
 
-finish:
-        free(alias_path);
+                        if (null_or_empty_path(path) > 0) {
+                                free(path);
+                                continue;
+                        }
 
 
-        return r;
-}
+                        if (force) {
+                                unlink(path);
 
 
-static int install_info_symlink_wants(InstallInfo *i, const char *config_path) {
-        char **s;
-        char *alias_path = NULL;
-        int r;
+                                if (symlink("/dev/null", path) >= 0) {
 
 
-        assert(i);
+                                        add_file_change(changes, n_changes, UNIT_FILE_UNLINK, path, NULL);
+                                        add_file_change(changes, n_changes, UNIT_FILE_SYMLINK, path, "/dev/null");
 
 
-        STRV_FOREACH(s, i->wanted_by) {
-                if (!unit_name_valid(*s)) {
-                        log_error("Invalid name %s.", *s);
-                        r = -EINVAL;
-                        goto finish;
+                                        free(path);
+                                        continue;
+                                }
+                        }
+
+                        if (r == 0)
+                                r = -EEXIST;
+                } else {
+                        if (r == 0)
+                                r = -errno;
                 }
 
                 }
 
-                free(alias_path);
-                alias_path = NULL;
+                free(path);
+        }
+
+        free(prefix);
+
+        return r;
+}
+
+int unit_file_unmask(
+                UnitFileScope scope,
+                bool runtime,
+                const char *root_dir,
+                char *files[],
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        char **i, *config_path = NULL;
+        int r, q;
+        Set *remove_symlinks_to = NULL;
 
 
-                if (asprintf(&alias_path, "%s/%s.wants/%s", config_path, *s, i->name) < 0) {
-                        log_error("Out of memory");
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
+
+        r = get_config_path(scope, runtime, root_dir, &config_path);
+        if (r < 0)
+                goto finish;
+
+        STRV_FOREACH(i, files) {
+                char *path;
+
+                if (!unit_name_is_valid_no_type(*i, true)) {
+                        if (r == 0)
+                                r = -EINVAL;
+                        continue;
+                }
+
+                path = path_make_absolute(*i, config_path);
+                if (!path) {
                         r = -ENOMEM;
                         r = -ENOMEM;
-                        goto finish;
+                        break;
                 }
 
                 }
 
-                if ((r = create_symlink(i->path, alias_path)) != 0)
-                        goto finish;
+                q = null_or_empty_path(path);
+                if (q > 0) {
+                        if (unlink(path) >= 0) {
+                                mark_symlink_for_removal(&remove_symlinks_to, path);
+                                add_file_change(changes, n_changes, UNIT_FILE_UNLINK, path, NULL);
+
+                                free(path);
+                                continue;
+                        }
+
+                        q = -errno;
+                }
+
+                if (q != -ENOENT && r == 0)
+                        r = q;
 
 
-                if (arg_action == ACTION_DISABLE)
-                        rmdir_parents(alias_path, config_path);
+                free(path);
         }
 
         }
 
-        r = 0;
 
 finish:
 
 finish:
-        free(alias_path);
+        q = remove_marked_symlinks(remove_symlinks_to, config_path, changes, n_changes);
+        if (r == 0)
+                r = q;
+
+        set_free_free(remove_symlinks_to);
+        free(config_path);
 
         return r;
 }
 
 
         return r;
 }
 
-static int install_info_apply(LookupPaths *paths, InstallInfo *i, const char *config_path) {
+int unit_file_link(
+                UnitFileScope scope,
+                bool runtime,
+                const char *root_dir,
+                char *files[],
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
 
 
-        const ConfigItem items[] = {
-                { "Alias",    config_parse_strv, &i->aliases,   "Install" },
-                { "WantedBy", config_parse_strv, &i->wanted_by, "Install" },
-                { "Also",     config_parse_also, NULL,          "Install" },
+        LookupPaths paths;
+        char **i, *config_path = NULL;
+        int r, q;
 
 
-                { NULL, NULL, NULL, NULL }
-        };
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
 
 
-        char **p;
-        char *filename = NULL;
-        FILE *f = NULL;
-        int r;
+        zero(paths);
 
 
-        assert(paths);
-        assert(i);
+        r = lookup_paths_init_from_scope(&paths, scope);
+        if (r < 0)
+                return r;
 
 
-        STRV_FOREACH(p, paths->unit_path) {
+        r = get_config_path(scope, runtime, root_dir, &config_path);
+        if (r < 0)
+                goto finish;
 
 
-                if (!(filename = path_make_absolute(i->name, *p))) {
-                        log_error("Out of memory");
-                        return -ENOMEM;
+        STRV_FOREACH(i, files) {
+                char *path, *fn;
+                struct stat st;
+
+                fn = file_name_from_path(*i);
+
+                if (!path_is_absolute(*i) ||
+                    !unit_name_is_valid_no_type(fn, true)) {
+                        if (r == 0)
+                                r = -EINVAL;
+                        continue;
+                }
+
+                if (lstat(*i, &st) < 0) {
+                        if (r == 0)
+                                r = -errno;
+                        continue;
+                }
+
+                if (!S_ISREG(st.st_mode)) {
+                        r = -ENOENT;
+                        continue;
                 }
 
                 }
 
-                if ((f = fopen(filename, "re")))
+                q = in_search_path(*i, paths.unit_path);
+                if (q < 0) {
+                        r = q;
                         break;
                         break;
+                }
 
 
-                free(filename);
-                filename = NULL;
+                if (q > 0)
+                        continue;
 
 
-                if (errno != ENOENT) {
-                        log_error("Failed to open %s: %m", filename);
-                        return -errno;
+                path = path_make_absolute(fn, config_path);
+                if (!path) {
+                        r = -ENOMEM;
+                        break;
                 }
                 }
-        }
 
 
-        if (!f) {
-                log_error("Couldn't find %s.", i->name);
-                return -ENOENT;
-        }
+                if (symlink(*i, path) >= 0) {
+                        add_file_change(changes, n_changes, UNIT_FILE_SYMLINK, path, *i);
 
 
-        i->path = filename;
+                        free(path);
+                        continue;
+                }
 
 
-        if ((r = config_parse(filename, f, NULL, items, true, i)) < 0) {
-                fclose(f);
-                return r;
-        }
+                if (errno == EEXIST) {
+                        char *dest = NULL;
 
 
-        fclose(f);
+                        q = readlink_and_make_absolute(path, &dest);
 
 
-        if ((r = install_info_symlink_alias(i, config_path)) != 0)
-                return r;
+                        if (q < 0 && errno != ENOENT) {
+                                free(path);
 
 
-        if ((r = install_info_symlink_wants(i, config_path)) != 0)
-                return r;
+                                if (r == 0)
+                                        r = q;
 
 
-        return 0;
-}
+                                continue;
+                        }
 
 
-static char *get_config_path(void) {
+                        if (q >= 0 && path_equal(dest, *i)) {
+                                free(dest);
+                                free(path);
+                                continue;
+                        }
+
+                        free(dest);
 
 
-        switch (arg_where) {
+                        if (force) {
+                                unlink(path);
 
 
-        case WHERE_SYSTEM:
-                return strdup(SYSTEM_CONFIG_UNIT_PATH);
+                                if (symlink(*i, path) >= 0) {
 
 
-        case WHERE_GLOBAL:
-                return strdup(SESSION_CONFIG_UNIT_PATH);
+                                        add_file_change(changes, n_changes, UNIT_FILE_UNLINK, path, NULL);
+                                        add_file_change(changes, n_changes, UNIT_FILE_SYMLINK, path, *i);
 
 
-        case WHERE_SESSION: {
-                char *p;
+                                        free(path);
+                                        continue;
+                                }
+                        }
 
 
-                if (session_config_home(&p) < 0)
-                        return NULL;
+                        if (r == 0)
+                                r = -EEXIST;
+                } else {
+                        if (r == 0)
+                                r = -errno;
+                }
 
 
-                return p;
+                free(path);
         }
 
         }
 
-        default:
-                assert_not_reached("Unknown config path.");
+                finish:
+        lookup_paths_free(&paths);
+        free(config_path);
+
+        return r;
+}
+
+void unit_file_list_free(Hashmap *h) {
+        UnitFileList *i;
+
+        while ((i = hashmap_steal_first(h))) {
+                free(i->path);
+                free(i);
         }
         }
+
+        hashmap_free(h);
 }
 
 }
 
-static int do_run(void) {
-        DBusConnection *bus = NULL;
-        DBusError error;
-        int r, q;
-        Iterator i;
-        InstallInfo *j;
+void unit_file_changes_free(UnitFileChange *changes, unsigned n_changes) {
+        unsigned i;
 
 
-        dbus_error_init(&error);
+        assert(changes || n_changes == 0);
 
 
-        if (arg_realize == REALIZE_NO)
-                return 0;
+        if (!changes)
+                return;
 
 
-        if (arg_where == WHERE_GLOBAL) {
-                log_warning("Warning: --realize has no effect with --global.");
-                return 0;
+        for (i = 0; i < n_changes; i++) {
+                free(changes[i].path);
+                free(changes[i].source);
         }
 
         }
 
-        if (arg_action != ACTION_ENABLE && arg_action != ACTION_DISABLE) {
-                log_warning("Warning: --realize has no effect with test.");
+        free(changes);
+}
+
+static void install_info_free(InstallInfo *i) {
+        assert(i);
+
+        free(i->name);
+        free(i->path);
+        strv_free(i->aliases);
+        strv_free(i->wanted_by);
+        free(i);
+}
+
+static void install_info_hashmap_free(Hashmap *m) {
+        InstallInfo *i;
+
+        if (!m)
+                return;
+
+        while ((i = hashmap_steal_first(m)))
+                install_info_free(i);
+
+        hashmap_free(m);
+}
+
+static void install_context_done(InstallContext *c) {
+        assert(c);
+
+        install_info_hashmap_free(c->will_install);
+        install_info_hashmap_free(c->have_installed);
+
+        c->will_install = c->have_installed = NULL;
+}
+
+static int install_info_add(
+                InstallContext *c,
+                const char *name,
+                const char *path) {
+        InstallInfo *i = NULL;
+        int r;
+
+        assert(c);
+        assert(name || path);
+
+        if (!name)
+                name = file_name_from_path(path);
+
+        if (!unit_name_is_valid_no_type(name, true))
+                return -EINVAL;
+
+        if (hashmap_get(c->have_installed, name) ||
+            hashmap_get(c->will_install, name))
                 return 0;
                 return 0;
+
+        r = hashmap_ensure_allocated(&c->will_install, string_hash_func, string_compare_func);
+        if (r < 0)
+                return r;
+
+        i = new0(InstallInfo, 1);
+        if (!i)
+                return -ENOMEM;
+
+        i->name = strdup(name);
+        if (!i->name) {
+                r = -ENOMEM;
+                goto fail;
         }
 
         }
 
-        if (arg_where == WHERE_SYSTEM && sd_booted() <= 0) {
-                log_info("systemd is not running, --realize has not effect.");
-                return 0;
+        if (path) {
+                i->path = strdup(path);
+                if (!i->path) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
         }
 
         }
 
-        if (arg_where == WHERE_SYSTEM && running_in_chroot() > 0) {
-                log_info("Running in a chroot() environment, --realize has no effect.");
-                return 0;
+        r = hashmap_put(c->will_install, i->name, i);
+        if (r < 0)
+                goto fail;
+
+        return 0;
+
+fail:
+        if (i)
+                install_info_free(i);
+
+        return r;
+}
+
+static int install_info_add_auto(
+                InstallContext *c,
+                const char *name_or_path) {
+
+        assert(c);
+        assert(name_or_path);
+
+        if (path_is_absolute(name_or_path))
+                return install_info_add(c, NULL, name_or_path);
+        else
+                return install_info_add(c, name_or_path, NULL);
+}
+
+static int config_parse_also(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        char *w;
+        size_t l;
+        char *state;
+        InstallContext *c = data;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+
+        FOREACH_WORD_QUOTED(w, l, rvalue, state) {
+                char *n;
+                int r;
+
+                n = strndup(w, l);
+                if (!n)
+                        return -ENOMEM;
+
+                r = install_info_add(c, n, NULL);
+                if (r < 0) {
+                        free(n);
+                        return r;
+                }
+
+                free(n);
         }
 
         }
 
-        if ((r = bus_connect(arg_where == WHERE_SESSION ? DBUS_BUS_SESSION : DBUS_BUS_SYSTEM, &bus, NULL, &error)) < 0) {
-                log_error("Failed to get D-Bus connection: %s", error.message);
-                goto finish;
+        return 0;
+}
+
+static int unit_file_load(
+                InstallContext *c,
+                InstallInfo *info,
+                const char *path,
+                bool allow_symlink) {
+
+        const ConfigTableItem items[] = {
+                { "Install", "Alias",    config_parse_strv, 0, &info->aliases   },
+                { "Install", "WantedBy", config_parse_strv, 0, &info->wanted_by },
+                { "Install", "Also",     config_parse_also, 0, c                },
+                { NULL, NULL, NULL, 0, NULL }
+        };
+
+        int fd;
+        FILE *f;
+        int r;
+
+        assert(c);
+        assert(info);
+        assert(path);
+
+        fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|(allow_symlink ? 0 : O_NOFOLLOW));
+        if (fd < 0)
+                return -errno;
+
+        f = fdopen(fd, "re");
+        if (!f) {
+                close_nointr_nofail(fd);
+                return -ENOMEM;
         }
 
         }
 
-        r = 0;
+        r = config_parse(path, f, NULL, config_item_table_lookup, (void*) items, true, info);
+        fclose(f);
+        if (r < 0)
+                return r;
 
 
-        if (arg_action == ACTION_ENABLE)
-                if ((r = daemon_reload(bus)) < 0)
-                        goto finish;
+        return strv_length(info->aliases) + strv_length(info->wanted_by);
+}
 
 
-        if (arg_realize != REALIZE_RELOAD) {
-                HASHMAP_FOREACH(j, have_installed, i)
-                        if ((q = install_info_run(bus, j)) < 0)
-                                r = q;
+static int unit_file_search(
+                InstallContext *c,
+                InstallInfo *info,
+                LookupPaths *paths,
+                const char *root_dir,
+                bool allow_symlink) {
+
+        char **p;
+        int r;
+
+        assert(c);
+        assert(info);
+        assert(paths);
+
+        if (info->path)
+                return unit_file_load(c, info, info->path, allow_symlink);
+
+        assert(info->name);
+
+        STRV_FOREACH(p, paths->unit_path) {
+                char *path = NULL;
+
+                if (isempty(root_dir))
+                        asprintf(&path, "%s/%s", *p, info->name);
+                else
+                        asprintf(&path, "%s/%s/%s", root_dir, *p, info->name);
+
+                if (!path)
+                        return -ENOMEM;
+
+                r = unit_file_load(c, info, path, allow_symlink);
+
+                if (r >= 0)
+                        info->path = path;
+                else
+                        free(path);
+
+                if (r != -ENOENT && r != -ELOOP)
+                        return r;
         }
 
         }
 
-        if (arg_action == ACTION_DISABLE)
-                if ((q = daemon_reload(bus)) < 0)
-                        r = q;
+        return -ENOENT;
+}
 
 
-finish:
-        if (bus)
-                dbus_connection_unref(bus);
+static int unit_file_can_install(
+                LookupPaths *paths,
+                const char *root_dir,
+                const char *name,
+                bool allow_symlink) {
+
+        InstallContext c;
+        InstallInfo *i;
+        int r;
+
+        assert(paths);
+        assert(name);
+
+        zero(c);
+
+        r = install_info_add_auto(&c, name);
+        if (r < 0)
+                return r;
+
+        assert_se(i = hashmap_first(c.will_install));
+
+        r = unit_file_search(&c, i, paths, root_dir, allow_symlink);
+
+        if (r >= 0)
+                r = strv_length(i->aliases) + strv_length(i->wanted_by);
 
 
-        dbus_error_free(&error);
+        install_context_done(&c);
 
 
-        dbus_shutdown();
         return r;
 }
 
         return r;
 }
 
-int main(int argc, char *argv[]) {
-        int r, retval = 1, j;
-        LookupPaths paths;
-        InstallInfo *i;
-        char *config_path = NULL;
+static int create_symlink(
+                const char *old_path,
+                const char *new_path,
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
 
 
-        zero(paths);
+        char *dest;
+        int r;
 
 
-        log_parse_environment();
+        assert(old_path);
+        assert(new_path);
 
 
-        if ((r = parse_argv(argc, argv)) < 0)
-                goto finish;
-        else if (r == 0) {
-                retval = 0;
-                goto finish;
-        }
+        mkdir_parents(new_path, 0755);
 
 
-        if ((r = lookup_paths_init(&paths, arg_where == WHERE_SYSTEM ? MANAGER_SYSTEM : MANAGER_SESSION)) < 0) {
-                log_error("Failed to determine lookup paths: %s", strerror(-r));
-                goto finish;
+        if (symlink(old_path, new_path) >= 0) {
+                add_file_change(changes, n_changes, UNIT_FILE_SYMLINK, new_path, old_path);
+                return 0;
         }
 
         }
 
-        if (!(config_path = get_config_path())) {
-                log_error("Failed to determine config path");
-                goto finish;
-        }
+        if (errno != EEXIST)
+                return -errno;
 
 
-        will_install = hashmap_new(string_hash_func, string_compare_func);
-        have_installed = hashmap_new(string_hash_func, string_compare_func);
+        r = readlink_and_make_absolute(new_path, &dest);
+        if (r < 0)
+                return r;
 
 
-        if (!will_install || !have_installed) {
-                log_error("Failed to allocate unit sets.");
-                goto finish;
+        if (path_equal(dest, old_path)) {
+                free(dest);
+                return 0;
         }
 
         }
 
-        for (j = optind; j < argc; j++)
-                if ((r = install_info_add(argv[j])) < 0)
-                        goto finish;
-
-        while ((i = hashmap_first(will_install))) {
-                assert_se(hashmap_move_one(have_installed, will_install, i->name) == 0);
+        free(dest);
 
 
-                if ((r = install_info_apply(&paths, i, config_path)) != 0) {
+        if (force)
+                return -EEXIST;
 
 
-                        if (r < 0)
-                                goto finish;
+        unlink(new_path);
 
 
-                        /* In test mode and found something */
-                        retval = 0;
-                        goto finish;
-                }
+        if (symlink(old_path, new_path) >= 0) {
+                add_file_change(changes, n_changes, UNIT_FILE_UNLINK, new_path, NULL);
+                add_file_change(changes, n_changes, UNIT_FILE_SYMLINK, new_path, old_path);
+                return 0;
         }
 
         }
 
-        if (do_run() < 0)
-                goto finish;
+        return -errno;
+}
 
 
-        retval = arg_action == ACTION_TEST ? 1 : 0;
+static int install_info_symlink_alias(
+                InstallInfo *i,
+                const char *config_path,
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
 
 
-finish:
-        install_info_hashmap_free(will_install);
-        install_info_hashmap_free(have_installed);
+        char **s;
+        int r = 0, q;
 
 
-        lookup_paths_free(&paths);
+        assert(i);
+        assert(config_path);
 
 
-        free(config_path);
+        STRV_FOREACH(s, i->aliases) {
+                char *alias_path;
 
 
-        return retval;
-}
+                alias_path = path_make_absolute(*s, config_path);
+
+                if (!alias_path)
+                        return -ENOMEM;
+
+                q = create_symlink(i->path, alias_path, force, changes, n_changes);
+                free(alias_path);
+
+                if (r == 0)
+                        r = q;
+        }
+
+        return r;
+}
+
+static int install_info_symlink_wants(
+                InstallInfo *i,
+                const char *config_path,
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        char **s;
+        int r = 0, q;
+
+        assert(i);
+        assert(config_path);
+
+        STRV_FOREACH(s, i->wanted_by) {
+                char *path;
+
+                if (!unit_name_is_valid_no_type(*s, true)) {
+                        r = -EINVAL;
+                        continue;
+                }
+
+                if (asprintf(&path, "%s/%s.wants/%s", config_path, *s, i->name) < 0)
+                        return -ENOMEM;
+
+                q = create_symlink(i->path, path, force, changes, n_changes);
+                free(path);
+
+                if (r == 0)
+                        r = q;
+        }
+
+        return r;
+}
+
+static int install_info_symlink_link(
+                InstallInfo *i,
+                LookupPaths *paths,
+                const char *config_path,
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        int r;
+        char *path;
+
+        assert(i);
+        assert(paths);
+        assert(config_path);
+        assert(i->path);
+
+        r = in_search_path(i->path, paths->unit_path);
+        if (r != 0)
+                return r;
+
+        if (asprintf(&path, "%s/%s", config_path, i->name) < 0)
+                return -ENOMEM;
+
+        r = create_symlink(i->path, path, force, changes, n_changes);
+        free(path);
+
+        return r;
+}
+
+static int install_info_apply(
+                InstallInfo *i,
+                LookupPaths *paths,
+                const char *config_path,
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        int r, q;
+
+        assert(i);
+        assert(paths);
+        assert(config_path);
+
+        r = install_info_symlink_alias(i, config_path, force, changes, n_changes);
+
+        q = install_info_symlink_wants(i, config_path, force, changes, n_changes);
+        if (r == 0)
+                r = q;
+
+        q = install_info_symlink_link(i, paths, config_path, force, changes, n_changes);
+        if (r == 0)
+                r = q;
+
+        return r;
+}
+
+static int install_context_apply(
+                InstallContext *c,
+                LookupPaths *paths,
+                const char *config_path,
+                const char *root_dir,
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        InstallInfo *i;
+        int r = 0, q;
+
+        assert(c);
+        assert(paths);
+        assert(config_path);
+
+        while ((i = hashmap_first(c->will_install))) {
+
+                q = hashmap_ensure_allocated(&c->have_installed, string_hash_func, string_compare_func);
+                if (q < 0)
+                        return q;
+
+                assert_se(hashmap_move_one(c->have_installed, c->will_install, i->name) == 0);
+
+                q = unit_file_search(c, i, paths, root_dir, false);
+                if (q < 0) {
+                        if (r >= 0)
+                                r = q;
+
+                        return r;
+                } else if (r >= 0)
+                        r += q;
+
+                q = install_info_apply(i, paths, config_path, force, changes, n_changes);
+                if (r >= 0 && q < 0)
+                        r = q;
+        }
+
+        return r;
+}
+
+static int install_context_mark_for_removal(
+                InstallContext *c,
+                LookupPaths *paths,
+                Set **remove_symlinks_to,
+                const char *config_path,
+                const char *root_dir) {
+
+        InstallInfo *i;
+        int r = 0, q;
+
+        assert(c);
+        assert(paths);
+        assert(config_path);
+
+        /* Marks all items for removal */
+
+        while ((i = hashmap_first(c->will_install))) {
+
+                q = hashmap_ensure_allocated(&c->have_installed, string_hash_func, string_compare_func);
+                if (q < 0)
+                        return q;
+
+                assert_se(hashmap_move_one(c->have_installed, c->will_install, i->name) == 0);
+
+                q = unit_file_search(c, i, paths, root_dir, false);
+                if (q < 0) {
+                        if (r >= 0)
+                                r = q;
+
+                        return r;
+                } else if (r >= 0)
+                        r += q;
+
+                q = mark_symlink_for_removal(remove_symlinks_to, i->name);
+                if (r >= 0 && q < 0)
+                        r = q;
+        }
+
+        return r;
+}
+
+int unit_file_enable(
+                UnitFileScope scope,
+                bool runtime,
+                const char *root_dir,
+                char *files[],
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        LookupPaths paths;
+        InstallContext c;
+        char **i, *config_path = NULL;
+        int r;
+
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
+
+        zero(paths);
+        zero(c);
+
+        r = lookup_paths_init_from_scope(&paths, scope);
+        if (r < 0)
+                return r;
+
+        r = get_config_path(scope, runtime, root_dir, &config_path);
+        if (r < 0)
+                goto finish;
+
+        STRV_FOREACH(i, files) {
+                r = install_info_add_auto(&c, *i);
+                if (r < 0)
+                        goto finish;
+        }
+
+        /* This will return the number of symlink rules that were
+        supposed to be created, not the ones actually created. This is
+        useful to determine whether the passed files hat any
+        installation data at all. */
+        r = install_context_apply(&c, &paths, config_path, root_dir, force, changes, n_changes);
+
+finish:
+        install_context_done(&c);
+        lookup_paths_free(&paths);
+        free(config_path);
+
+        return r;
+}
+
+int unit_file_disable(
+                UnitFileScope scope,
+                bool runtime,
+                const char *root_dir,
+                char *files[],
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        LookupPaths paths;
+        InstallContext c;
+        char **i, *config_path = NULL;
+        Set *remove_symlinks_to = NULL;
+        int r, q;
+
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
+
+        zero(paths);
+        zero(c);
+
+        r = lookup_paths_init_from_scope(&paths, scope);
+        if (r < 0)
+                return r;
+
+        r = get_config_path(scope, runtime, root_dir, &config_path);
+        if (r < 0)
+                goto finish;
+
+        STRV_FOREACH(i, files) {
+                r = install_info_add_auto(&c, *i);
+                if (r < 0)
+                        goto finish;
+        }
+
+        r = install_context_mark_for_removal(&c, &paths, &remove_symlinks_to, config_path, root_dir);
+
+        q = remove_marked_symlinks(remove_symlinks_to, config_path, changes, n_changes);
+        if (r == 0)
+                r = q;
+
+finish:
+        install_context_done(&c);
+        lookup_paths_free(&paths);
+        set_free_free(remove_symlinks_to);
+        free(config_path);
+
+        return r;
+}
+
+int unit_file_reenable(
+                UnitFileScope scope,
+                bool runtime,
+                const char *root_dir,
+                char *files[],
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        LookupPaths paths;
+        InstallContext c;
+        char **i, *config_path = NULL;
+        Set *remove_symlinks_to = NULL;
+        int r, q;
+
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
+
+        zero(paths);
+        zero(c);
+
+        r = lookup_paths_init_from_scope(&paths, scope);
+        if (r < 0)
+                return r;
+
+        r = get_config_path(scope, runtime, root_dir, &config_path);
+        if (r < 0)
+                goto finish;
+
+        STRV_FOREACH(i, files) {
+                r = mark_symlink_for_removal(&remove_symlinks_to, *i);
+                if (r < 0)
+                        goto finish;
+
+                r = install_info_add_auto(&c, *i);
+                if (r < 0)
+                        goto finish;
+        }
+
+        r = remove_marked_symlinks(remove_symlinks_to, config_path, changes, n_changes);
+
+        /* Returns number of symlinks that where supposed to be installed. */
+        q = install_context_apply(&c, &paths, config_path, root_dir, force, changes, n_changes);
+        if (r == 0)
+                r = q;
+
+finish:
+        lookup_paths_free(&paths);
+        install_context_done(&c);
+        set_free_free(remove_symlinks_to);
+        free(config_path);
+
+        return r;
+}
+
+UnitFileState unit_file_get_state(
+                UnitFileScope scope,
+                const char *root_dir,
+                const char *name) {
+
+        LookupPaths paths;
+        UnitFileState state = _UNIT_FILE_STATE_INVALID;
+        char **i, *path = NULL;
+        int r;
+
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
+        assert(name);
+
+        zero(paths);
+
+        if (root_dir && scope != UNIT_FILE_SYSTEM)
+                return -EINVAL;
+
+        if (!unit_name_is_valid_no_type(name, true))
+                return -EINVAL;
+
+        r = lookup_paths_init_from_scope(&paths, scope);
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(i, paths.unit_path) {
+                struct stat st;
+
+                free(path);
+                path = NULL;
+
+                if (root_dir)
+                        asprintf(&path, "%s/%s/%s", root_dir, *i, name);
+                else
+                        asprintf(&path, "%s/%s", *i, name);
+
+                if (!path) {
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                if (lstat(path, &st) < 0) {
+                        if (errno == ENOENT)
+                                continue;
+
+                        r = -errno;
+                        goto finish;
+                }
+
+                if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode)) {
+                        r = -ENOENT;
+                        goto finish;
+                }
+
+                r = null_or_empty_path(path);
+                if (r < 0 && r != -ENOENT)
+                        goto finish;
+                else if (r > 0) {
+                        state = path_startswith(*i, "/run") ?
+                                UNIT_FILE_MASKED_RUNTIME : UNIT_FILE_MASKED;
+                        r = 0;
+                        goto finish;
+                }
+
+                r = find_symlinks_in_scope(scope, root_dir, name, &state);
+                if (r < 0) {
+                        goto finish;
+                } else if (r > 0) {
+                        r = 0;
+                        goto finish;
+                }
+
+                r = unit_file_can_install(&paths, root_dir, path, true);
+                if (r < 0 && errno != -ENOENT)
+                        goto finish;
+                else if (r > 0) {
+                        state = UNIT_FILE_DISABLED;
+                        r = 0;
+                        goto finish;
+                } else if (r == 0) {
+                        state = UNIT_FILE_STATIC;
+                        r = 0;
+                        goto finish;
+                }
+        }
+
+finish:
+        lookup_paths_free(&paths);
+        free(path);
+
+        return r < 0 ? r : state;
+}
+
+int unit_file_query_preset(UnitFileScope scope, const char *name) {
+        char **files, **i;
+        int r;
+
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
+        assert(name);
+
+        if (scope == UNIT_FILE_SYSTEM)
+                r = conf_files_list(&files, ".preset",
+                                    "/etc/systemd/system.preset",
+                                    "/usr/local/lib/systemd/system.preset",
+                                    "/usr/lib/systemd/system.preset",
+                                    "/lib/systemd/system.preset",
+                                    NULL);
+        else if (scope == UNIT_FILE_GLOBAL)
+                r = conf_files_list(&files, ".preset",
+                                    "/etc/systemd/user.preset",
+                                    "/usr/local/lib/systemd/user.preset",
+                                    "/usr/lib/systemd/user.preset",
+                                    NULL);
+        else
+                return 1;
+
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(i, files) {
+                FILE *f;
+
+                f = fopen(*i, "re");
+                if (!f) {
+                        if (errno == ENOENT)
+                                continue;
+
+                        r = -errno;
+                        goto finish;
+                }
+
+                for (;;) {
+                        char line[LINE_MAX], *l;
+
+                        if (!fgets(line, sizeof(line), f))
+                                break;
+
+                        l = strstrip(line);
+                        if (!*l)
+                                continue;
+
+                        if (strchr(COMMENTS, *l))
+                                continue;
+
+                        if (first_word(l, "enable")) {
+                                l += 6;
+                                l += strspn(l, WHITESPACE);
+
+                                if (fnmatch(l, name, FNM_NOESCAPE) == 0) {
+                                        r = 1;
+                                        fclose(f);
+                                        goto finish;
+                                }
+                        } else if (first_word(l, "disable")) {
+                                l += 7;
+                                l += strspn(l, WHITESPACE);
+
+                                if (fnmatch(l, name, FNM_NOESCAPE) == 0) {
+                                        r = 0;
+                                        fclose(f);
+                                        goto finish;
+                                }
+                        } else
+                                log_debug("Couldn't parse line '%s'", l);
+                }
+
+                fclose(f);
+        }
+
+        /* Default is "enable" */
+        r = 1;
+
+finish:
+        strv_free(files);
+
+        return r;
+}
+
+int unit_file_preset(
+                UnitFileScope scope,
+                bool runtime,
+                const char *root_dir,
+                char *files[],
+                bool force,
+                UnitFileChange **changes,
+                unsigned *n_changes) {
+
+        LookupPaths paths;
+        InstallContext plus, minus;
+        char **i, *config_path = NULL;
+        Set *remove_symlinks_to = NULL;
+        int r, q;
+
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
+
+        zero(paths);
+        zero(plus);
+        zero(minus);
+
+        r = lookup_paths_init_from_scope(&paths, scope);
+        if (r < 0)
+                return r;
+
+        r = get_config_path(scope, runtime, root_dir, &config_path);
+        if (r < 0)
+                goto finish;
+
+        STRV_FOREACH(i, files) {
+
+                if (!unit_name_is_valid_no_type(*i, true)) {
+                        r = -EINVAL;
+                        goto finish;
+                }
+
+                r = unit_file_query_preset(scope, *i);
+                if (r < 0)
+                        goto finish;
+
+                if (r)
+                        r = install_info_add_auto(&plus, *i);
+                else
+                        r = install_info_add_auto(&minus, *i);
+
+                if (r < 0)
+                        goto finish;
+        }
+
+        r = install_context_mark_for_removal(&minus, &paths, &remove_symlinks_to, config_path, root_dir);
+
+        q = remove_marked_symlinks(remove_symlinks_to, config_path, changes, n_changes);
+        if (r == 0)
+                r = q;
+
+        /* Returns number of symlinks that where supposed to be installed. */
+        q = install_context_apply(&plus, &paths, config_path, root_dir, force, changes, n_changes);
+        if (r == 0)
+                r = q;
+
+finish:
+        lookup_paths_free(&paths);
+        install_context_done(&plus);
+        install_context_done(&minus);
+        set_free_free(remove_symlinks_to);
+        free(config_path);
+
+        return r;
+}
+
+int unit_file_get_list(
+                UnitFileScope scope,
+                const char *root_dir,
+                Hashmap *h) {
+
+        LookupPaths paths;
+        char **i, *buf = NULL;
+        DIR *d = NULL;
+        int r;
+
+        assert(scope >= 0);
+        assert(scope < _UNIT_FILE_SCOPE_MAX);
+        assert(h);
+
+        zero(paths);
+
+        if (root_dir && scope != UNIT_FILE_SYSTEM)
+                return -EINVAL;
+
+        r = lookup_paths_init_from_scope(&paths, scope);
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(i, paths.unit_path) {
+                struct dirent buffer, *de;
+                const char *units_dir;
+
+                free(buf);
+                buf = NULL;
+
+                if (root_dir) {
+                        if (asprintf(&buf, "%s/%s", root_dir, *i) < 0) {
+                                r = -ENOMEM;
+                                goto finish;
+                        }
+                        units_dir = buf;
+                } else
+                        units_dir = *i;
+
+                if (d)
+                        closedir(d);
+
+                d = opendir(units_dir);
+                if (!d) {
+                        if (errno == ENOENT)
+                                continue;
+
+                        r = -errno;
+                        goto finish;
+                }
+
+                for (;;) {
+                        UnitFileList *f;
+
+                        r = readdir_r(d, &buffer, &de);
+                        if (r != 0) {
+                                r = -r;
+                                goto finish;
+                        }
+
+                        if (!de)
+                                break;
+
+                        if (ignore_file(de->d_name))
+                                continue;
+
+                        if (!unit_name_is_valid_no_type(de->d_name, true))
+                                continue;
+
+                        if (hashmap_get(h, de->d_name))
+                                continue;
+
+                        r = dirent_ensure_type(d, de);
+                        if (r < 0) {
+                                if (errno == ENOENT)
+                                        continue;
+
+                                goto finish;
+                        }
+
+                        if (de->d_type != DT_LNK && de->d_type != DT_REG)
+                                continue;
+
+                        f = new0(UnitFileList, 1);
+                        if (!f) {
+                                r = -ENOMEM;
+                                goto finish;
+                        }
+
+                        f->path = path_make_absolute(de->d_name, units_dir);
+                        if (!f->path) {
+                                free(f);
+                                r = -ENOMEM;
+                                goto finish;
+                        }
+
+                        r = null_or_empty_path(f->path);
+                        if (r < 0 && r != -ENOENT) {
+                                free(f->path);
+                                free(f);
+                                goto finish;
+                        } else if (r > 0) {
+                                f->state =
+                                        path_startswith(*i, "/run") ?
+                                        UNIT_FILE_MASKED_RUNTIME : UNIT_FILE_MASKED;
+                                goto found;
+                        }
+
+                        r = find_symlinks_in_scope(scope, root_dir, de->d_name, &f->state);
+                        if (r < 0) {
+                                free(f->path);
+                                free(f);
+                                goto finish;
+                        } else if (r > 0)
+                                goto found;
+
+                        r = unit_file_can_install(&paths, root_dir, f->path, true);
+                        if (r < 0) {
+                                free(f->path);
+                                free(f);
+                                goto finish;
+                        } else if (r > 0) {
+                                f->state = UNIT_FILE_DISABLED;
+                                goto found;
+                        } else {
+                                f->state = UNIT_FILE_STATIC;
+                                goto found;
+                        }
+
+                        free(f->path);
+                        free(f);
+                        continue;
+
+                found:
+                        r = hashmap_put(h, file_name_from_path(f->path), f);
+                        if (r < 0) {
+                                free(f->path);
+                                free(f);
+                                goto finish;
+                        }
+                }
+        }
+
+finish:
+        lookup_paths_free(&paths);
+        free(buf);
+
+        if (d)
+                closedir(d);
+
+        return r;
+}
+
+static const char* const unit_file_state_table[_UNIT_FILE_STATE_MAX] = {
+        [UNIT_FILE_ENABLED] = "enabled",
+        [UNIT_FILE_ENABLED_RUNTIME] = "enabled-runtie",
+        [UNIT_FILE_LINKED] = "linked",
+        [UNIT_FILE_LINKED_RUNTIME] = "linked-runtime",
+        [UNIT_FILE_MASKED] = "masked",
+        [UNIT_FILE_MASKED_RUNTIME] = "masked-runtime",
+        [UNIT_FILE_STATIC] = "static",
+        [UNIT_FILE_DISABLED] = "disabled"
+};
+
+DEFINE_STRING_TABLE_LOOKUP(unit_file_state, UnitFileState);
+
+static const char* const unit_file_change_type_table[_UNIT_FILE_CHANGE_TYPE_MAX] = {
+        [UNIT_FILE_SYMLINK] = "symlink",
+        [UNIT_FILE_UNLINK] = "unlink",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(unit_file_change_type, UnitFileChangeType);