core: rework unit name validation and manipulation logic

A variety of changes:

- Make sure all our calls distuingish OOM from other errors if OOM is
  not the only error possible.

- Be much stricter when parsing escaped paths, do not accept trailing or
  leading escaped slashes.

- Change unit validation to take a bit mask for allowing plain names,
  instance names or template names or an combination thereof.

- Refuse manipulating invalid unit name

src/core/automount.c

@@ -167,8 +167,9 @@ static int automount_add_default_dependencies(Automount *a) {
 }
 
 static int automount_verify(Automount *a) {
-        bool b;
         _cleanup_free_ char *e = NULL;
+        int r;
+
         assert(a);
 
         if (UNIT(a)->load_state != UNIT_LOADED)
@@ -179,13 +180,11 @@ static int automount_verify(Automount *a) {
                 return -EINVAL;
         }
 
-        e = unit_name_from_path(a->where, ".automount");
-        if (!e)
-                return -ENOMEM;
-
-        b = unit_has_name(UNIT(a), e);
+        r = unit_name_from_path(a->where, ".automount", &e);
+        if (r < 0)
+                return log_unit_error(UNIT(a)->id, "Failed to generate unit name from path: %m");
 
-        if (!b) {
+        if (!unit_has_name(UNIT(a), e)) {
                 log_unit_error(UNIT(a)->id, "%s's Where setting doesn't match unit name. Refusing.", UNIT(a)->id);
                 return -EINVAL;
         }
@@ -209,9 +208,9 @@ static int automount_load(Unit *u) {
                 Unit *x;
 
                 if (!a->where) {
-                        a->where = unit_name_to_path(u->id);
-                        if (!a->where)
-                                return -ENOMEM;
+                        r = unit_name_to_path(u->id, &a->where);
+                        if (r < 0)
+                                return r;
                 }
 
                 path_kill_slashes(a->where);

src/core/busname.c

@@ -163,9 +163,9 @@ static int busname_add_extras(BusName *n) {
         assert(n);
 
         if (!n->name) {
-                n->name = unit_name_to_prefix(u->id);
-                if (!n->name)
-                        return -ENOMEM;
+                r = unit_name_to_prefix(u->id, &n->name);
+                if (r < 0)
+                        return r;
         }
 
         if (!u->description) {

src/core/dbus-unit.c

@@ -940,7 +940,7 @@ static int bus_unit_set_transient_property(
                 if (r < 0)
                         return r;
 
-                if (!unit_name_is_valid(s, TEMPLATE_INVALID) || !endswith(s, ".slice"))
+                if (!unit_name_is_valid(s, UNIT_NAME_PLAIN) || !endswith(s, ".slice"))
                         return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid slice name %s", s);
 
                 if (isempty(s)) {
@@ -988,7 +988,7 @@ static int bus_unit_set_transient_property(
                         return r;
 
                 while ((r = sd_bus_message_read(message, "s", &other)) > 0) {
-                        if (!unit_name_is_valid(other, TEMPLATE_INVALID))
+                        if (!unit_name_is_valid(other, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE))
                                 return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid unit name %s", other);
 
                         if (mode != UNIT_CHECK) {

src/core/device.c

@@ -279,9 +279,9 @@ static int device_add_udev_wants(Unit *u, struct udev_device *dev) {
                 memcpy(e, word, l);
                 e[l] = 0;
 
-                n = unit_name_mangle(e, MANGLE_NOGLOB);
-                if (!n)
-                        return log_oom();
+                r = unit_name_mangle(e, UNIT_NAME_NOGLOB, &n);
+                if (r < 0)
+                        return log_unit_error_errno(u->id, r, "Failed to mangle unit name: %m");
 
                 r = unit_add_dependency_by_name(u, UNIT_WANTS, n, NULL, true);
                 if (r < 0)
@@ -308,9 +308,9 @@ static int device_setup_unit(Manager *m, struct udev_device *dev, const char *pa
         if (!sysfs)
                 return 0;
 
-        e = unit_name_from_path(path, ".device");
-        if (!e)
-                return log_oom();
+        r = unit_name_from_path(path, ".device", &e);
+        if (r < 0)
+                return log_unit_error_errno(u->id, r, "Failed to generate device name: %m");
 
         u = manager_get_unit(m, e);
 
@@ -491,16 +491,17 @@ static int device_update_found_by_sysfs(Manager *m, const char *sysfs, bool add,
 static int device_update_found_by_name(Manager *m, const char *path, bool add, DeviceFound found, bool now) {
         _cleanup_free_ char *e = NULL;
         Unit *u;
+        int r;
 
         assert(m);
         assert(path);
 
         if (found == DEVICE_NOT_FOUND)
                 return 0;
 
-        e = unit_name_from_path(path, ".device");
-        if (!e)
-                return log_oom();
+        r = unit_name_from_path(path, ".device", &e);
+        if (r < 0)
+                return log_error_errno(r, "Failed to generate unit name from device path: %m");
 
         u = manager_get_unit(m, e);
         if (!u)

src/core/load-fragment.c

@@ -3394,7 +3394,7 @@ static int open_follow(char **filename, FILE **_f, Set *names, char **_final) {
                  * unit name. */
                 name = basename(*filename);
 
-                if (unit_name_is_valid(name, TEMPLATE_VALID)) {
+                if (unit_name_is_valid(name, UNIT_NAME_ANY)) {
 
                         id = set_get(names, name);
                         if (!id) {
@@ -3642,11 +3642,11 @@ int unit_load_fragment(Unit *u) {
 
         /* Look for a template */
         if (u->load_state == UNIT_STUB && u->instance) {
-                _cleanup_free_ char *k;
+                _cleanup_free_ char *k = NULL;
 
-                k = unit_name_template(u->id);
-                if (!k)
-                        return -ENOMEM;
+                r = unit_name_template(u->id, &k);
+                if (r < 0)
+                        return r;
 
                 r = load_from_path(u, k);
                 if (r < 0)
@@ -3659,9 +3659,9 @@ int unit_load_fragment(Unit *u) {
                                 if (t == u->id)
                                         continue;
 
-                                z = unit_name_template(t);
-                                if (!z)
-                                        return -ENOMEM;
+                                r = unit_name_template(t, &z);
+                                if (r < 0)
+                                        return r;
 
                                 r = load_from_path(u, z);
                                 if (r < 0)

src/core/manager.c

@@ -1306,7 +1306,7 @@ int manager_load_unit_prepare(
 
         t = unit_name_to_type(name);
 
-        if (t == _UNIT_TYPE_INVALID || !unit_name_is_valid(name, TEMPLATE_INVALID))
+        if (t == _UNIT_TYPE_INVALID || !unit_name_is_valid(name, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE))
                 return sd_bus_error_setf(e, SD_BUS_ERROR_INVALID_ARGS, "Unit name %s is not valid.", name);
 
         ret = manager_get_unit(m, name);
@@ -2093,7 +2093,7 @@ void manager_send_unit_audit(Manager *m, Unit *u, int type, bool success) {
 #ifdef HAVE_AUDIT
         _cleanup_free_ char *p = NULL;
         const char *msg;
-        int audit_fd;
+        int audit_fd, r;
 
         audit_fd = get_audit_fd();
         if (audit_fd < 0)
@@ -2110,9 +2110,9 @@ void manager_send_unit_audit(Manager *m, Unit *u, int type, bool success) {
         if (u->type != UNIT_SERVICE)
                 return;
 
-        p = unit_name_to_prefix_and_instance(u->id);
-        if (!p) {
-                log_oom();
+        r = unit_name_to_prefix_and_instance(u->id, &p);
+        if (r < 0) {
+                log_error_errno(r, "Failed to extract prefix and instance of unit name: %m");
                 return;
         }
 
@@ -3027,15 +3027,16 @@ void manager_status_printf(Manager *m, StatusType type, const char *status, cons
 int manager_get_unit_by_path(Manager *m, const char *path, const char *suffix, Unit **_found) {
         _cleanup_free_ char *p = NULL;
         Unit *found;
+        int r;
 
         assert(m);
         assert(path);
         assert(suffix);
         assert(_found);
 
-        p = unit_name_from_path(path, suffix);
-        if (!p)
-                return -ENOMEM;
+        r = unit_name_from_path(path, suffix, &p);
+        if (r < 0)
+                return r;
 
         found = manager_get_unit(m, p);
         if (!found) {

src/core/mount.c

@@ -435,7 +435,7 @@ static int mount_add_default_dependencies(Mount *m) {
 
 static int mount_verify(Mount *m) {
         _cleanup_free_ char *e = NULL;
-        bool b;
+        int r;
 
         assert(m);
 
@@ -445,12 +445,11 @@ static int mount_verify(Mount *m) {
         if (!m->from_fragment && !m->from_proc_self_mountinfo)
                 return -ENOENT;
 
-        e = unit_name_from_path(m->where, ".mount");
-        if (!e)
-                return -ENOMEM;
+        r = unit_name_from_path(m->where, ".mount", &e);
+        if (r < 0)
+                return log_unit_error_errno(UNIT(m)->id, r, "Failed to generate unit name from mount path: %m");
 
-        b = unit_has_name(UNIT(m), e);
-        if (!b) {
+        if (!unit_has_name(UNIT(m), e)) {
                 log_unit_error(UNIT(m)->id, "%s's Where= setting doesn't match unit name. Refusing.", UNIT(m)->id);
                 return -EINVAL;
         }
@@ -483,9 +482,9 @@ static int mount_add_extras(Mount *m) {
                 m->from_fragment = true;
 
         if (!m->where) {
-                m->where = unit_name_to_path(u->id);
-                if (!m->where)
-                        return -ENOMEM;
+                r = unit_name_to_path(u->id, &m->where);
+                if (r < 0)
+                        return r;
         }
 
         path_kill_slashes(m->where);
@@ -1419,9 +1418,9 @@ static int mount_setup_unit(
         if (!is_path(where))
                 return 0;
 
-        e = unit_name_from_path(where, ".mount");
-        if (!e)
-                return -ENOMEM;
+        r = unit_name_from_path(where, ".mount", &e);
+        if (r < 0)
+                return r;
 
         u = manager_get_unit(m, e);
         if (!u) {

src/core/snapshot.c

@@ -201,10 +201,10 @@ int snapshot_create(Manager *m, const char *name, bool cleanup, sd_bus_error *e,
         assert(_s);
 
         if (name) {
-                if (!unit_name_is_valid(name, TEMPLATE_INVALID))
+                if (!unit_name_is_valid(name, UNIT_NAME_PLAIN))
                         return sd_bus_error_setf(e, SD_BUS_ERROR_INVALID_ARGS, "Unit name %s is not valid.", name);
 
-                if (unit_name_to_type(name) != UNIT_SNAPSHOT)
+                if (!endswith(name, ".snapshot"))
                         return sd_bus_error_setf(e, SD_BUS_ERROR_INVALID_ARGS, "Unit name %s lacks snapshot suffix.", name);
 
                 if (manager_get_unit(m, name))

src/core/socket.c

@@ -196,12 +196,15 @@ int socket_instantiate_service(Socket *s) {
          * here. For Accept=no this is mostly a NOP since the service
          * is figured out at load time anyway. */
 
-        if (UNIT_DEREF(s->service) || !s->accept)
+        if (UNIT_DEREF(s->service))
                 return 0;
 
-        prefix = unit_name_to_prefix(UNIT(s)->id);
-        if (!prefix)
-                return -ENOMEM;
+        if (!s->accept)
+                return 0;
+
+        r = unit_name_to_prefix(UNIT(s)->id, &prefix);
+        if (r < 0)
+                return r;
 
         if (asprintf(&name, "%s@%u.service", prefix, s->n_accepted) < 0)
                 return -ENOMEM;
@@ -1836,17 +1839,13 @@ static void socket_enter_running(Socket *s, int cfd) {
                         return;
                 }
 
-                prefix = unit_name_to_prefix(UNIT(s)->id);
-                if (!prefix) {
-                        r = -ENOMEM;
+                r = unit_name_to_prefix(UNIT(s)->id, &prefix);
+                if (r < 0)
                         goto fail;
-                }
 
-                name = unit_name_build(prefix, instance, ".service");
-                if (!name) {
-                        r = -ENOMEM;
+                r = unit_name_build(prefix, instance, ".service", &name);
+                if (r < 0)
                         goto fail;
-                }
 
                 r = unit_add_name(UNIT_DEREF(s->service), name);
                 if (r < 0)

src/core/swap.c

@@ -222,18 +222,17 @@ static int swap_add_default_dependencies(Swap *s) {
 }
 
 static int swap_verify(Swap *s) {
-        bool b;
         _cleanup_free_ char *e = NULL;
+        int r;
 
         if (UNIT(s)->load_state != UNIT_LOADED)
                 return 0;
 
-        e = unit_name_from_path(s->what, ".swap");
-        if (!e)
-                return log_oom();
+        r = unit_name_from_path(s->what, ".swap", &e);
+        if (r < 0)
+                return log_unit_error_errno(UNIT(s)->id, r, "%s: failed to generate unit name from path: %m", UNIT(s)->id);
 
-        b = unit_has_name(UNIT(s), e);
-        if (!b) {
+        if (!unit_has_name(UNIT(s), e)) {
                 log_unit_error(UNIT(s)->id, "%s: Value of \"What\" and unit name do not match, not loading.", UNIT(s)->id);
                 return -EINVAL;
         }
@@ -289,8 +288,11 @@ static int swap_load(Unit *u) {
                                 s->what = strdup(s->parameters_fragment.what);
                         else if (s->parameters_proc_swaps.what)
                                 s->what = strdup(s->parameters_proc_swaps.what);
-                        else
-                                s->what = unit_name_to_path(u->id);
+                        else {
+                                r = unit_name_to_path(u->id, &s->what);
+                                if (r < 0)
+                                        return r;
+                        }
 
                         if (!s->what)
                                 return -ENOMEM;
@@ -355,9 +357,9 @@ static int swap_setup_unit(
         assert(what);
         assert(what_proc_swaps);
 
-        e = unit_name_from_path(what, ".swap");
-        if (!e)
-                return log_oom();
+        r = unit_name_from_path(what, ".swap", &e);
+        if (r < 0)
+                return log_unit_error_errno(u->id, r, "Failed to generate unit name from path: %m");
 
         u = manager_get_unit(m, e);
 
@@ -1329,9 +1331,9 @@ int swap_process_device_new(Manager *m, struct udev_device *dev) {
         if (!dn)
                 return 0;
 
-        e = unit_name_from_path(dn, ".swap");
-        if (!e)
-                return -ENOMEM;
+        r = unit_name_from_path(dn, ".swap", &e);
+        if (r < 0)
+                return r;
 
         s = hashmap_get(m->units, e);
         if (s)
@@ -1340,15 +1342,14 @@ int swap_process_device_new(Manager *m, struct udev_device *dev) {
         first = udev_device_get_devlinks_list_entry(dev);
         udev_list_entry_foreach(item, first) {
                 _cleanup_free_ char *n = NULL;
+                int q;
 
-                n = unit_name_from_path(udev_list_entry_get_name(item), ".swap");
-                if (!n)
-                        return -ENOMEM;
+                q = unit_name_from_path(udev_list_entry_get_name(item), ".swap", &n);
+                if (q < 0)
+                        return q;
 
                 s = hashmap_get(m->units, n);
                 if (s) {
-                        int q;
-
                         q = swap_set_devnode(s, dn);
                         if (q < 0)
                                 r = q;