tree-wide: use ERFKILL instead of ESHUTDOWN for "unit masked"

If the error code ever leaks (we print the strerror error instead of providing
our own), the message for ESHUTDOWN is "Cannot send after transport endpoint
shutdown", which can be misleading. In particular it suggest that some
mishandling of the dbus connection occured. Let's change that to ERFKILL which
has the advantage that a) it sounds implausible as actual error, b) has the
connotation of disabling something manually.

src/core/dbus-manager.c

@@ -1610,7 +1610,7 @@ fail:
 static int install_error(sd_bus_error *error, int c) {
         assert(c < 0);
 
-        if (c == -ESHUTDOWN)
+        if (c == -ERFKILL)
                 return sd_bus_error_setf(error, BUS_ERROR_UNIT_MASKED, "Unit file is masked.");
         if (c == -EADDRNOTAVAIL)
                 return sd_bus_error_setf(error, BUS_ERROR_UNIT_GENERATED, "Unit file is transient or generated.");

src/core/transaction.c

@@ -939,7 +939,7 @@ int transaction_add_job_and_dependencies(
                                 if (r < 0) {
                                         /* unit masked, job type not applicable and unit not found are not considered as errors. */
                                         log_unit_full(dep,
-                                                      IN_SET(r, -ESHUTDOWN, -EBADR, -ENOENT) ? LOG_DEBUG : LOG_WARNING,
+                                                      IN_SET(r, -ERFKILL, -EBADR, -ENOENT) ? LOG_DEBUG : LOG_WARNING,
                                                       r, "Cannot add dependency job, ignoring: %s",
                                                       bus_error_message(e, r));
                                         sd_bus_error_free(e);

src/shared/install.c

@@ -754,7 +754,7 @@ static int install_info_may_process(UnitFileInstallInfo *i, const LookupPaths *p
          * not subject to enable/disable operations. */
 
         if (i->type == UNIT_FILE_TYPE_MASKED)
-                return -ESHUTDOWN;
+                return -ERFKILL;
         if (path_is_generator(paths, i->path))
                 return -EADDRNOTAVAIL;
         if (path_is_transient(paths, i->path))

src/systemctl/systemctl.c

@@ -5272,7 +5272,7 @@ static int enable_sysv_units(const char *verb, char **args) {
                         continue;
 
                 j = unit_file_exists(arg_scope, &paths, name);
-                if (j < 0 && !IN_SET(j, -ELOOP, -ESHUTDOWN, -EADDRNOTAVAIL))
+                if (j < 0 && !IN_SET(j, -ELOOP, -ERFKILL, -EADDRNOTAVAIL))
                         return log_error_errno(j, "Failed to lookup unit file state: %m");
                 found_native = j != 0;
 
@@ -5442,7 +5442,7 @@ static int enable_unit(int argc, char *argv[], void *userdata) {
                 else
                         assert_not_reached("Unknown verb");
 
-                if (r == -ESHUTDOWN)
+                if (r == -ERFKILL)
                         return log_error_errno(r, "Unit file is masked.");
                 if (r == -EADDRNOTAVAIL)
                         return log_error_errno(r, "Unit file is transient or generated.");
@@ -5617,7 +5617,7 @@ static int add_dependency(int argc, char *argv[], void *userdata) {
                 unsigned n_changes = 0;
 
                 r = unit_file_add_dependency(arg_scope, arg_runtime, arg_root, names, target, dep, arg_force, &changes, &n_changes);
-                if (r == -ESHUTDOWN)
+                if (r == -ERFKILL)
                         return log_error_errno(r, "Unit file is masked.");
                 if (r == -EADDRNOTAVAIL)
                         return log_error_errno(r, "Unit file is transient or generated.");

src/sysv-generator/sysv-generator.c

@@ -807,7 +807,7 @@ static int enumerate_sysv(const LookupPaths *lp, Hashmap *all_services) {
                                 continue;
 
                         r = unit_file_exists(UNIT_FILE_SYSTEM, lp, name);
-                        if (r < 0 && !IN_SET(r, -ELOOP, -ESHUTDOWN, -EADDRNOTAVAIL)) {
+                        if (r < 0 && !IN_SET(r, -ELOOP, -ERFKILL, -EADDRNOTAVAIL)) {
                                 log_debug_errno(r, "Failed to detect whether %s exists, skipping: %m", name);
                                 continue;
                         } else if (r != 0) {

src/test/test-install-root.c

@@ -80,7 +80,7 @@ static void test_basic_mask_and_enable(const char *root) {
         assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "d.service", &state) >= 0 && state == UNIT_FILE_MASKED);
 
         /* Enabling a masked unit should fail! */
-        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("a.service"), false, &changes, &n_changes) == -ESHUTDOWN);
+        assert_se(unit_file_enable(UNIT_FILE_SYSTEM, false, root, STRV_MAKE("a.service"), false, &changes, &n_changes) == -ERFKILL);
         unit_file_changes_free(changes, n_changes);
         changes = NULL; n_changes = 0;