service: start Arch daemons

Arch does not use proper SysV runlevels. Instead /etc/rc.conf contains
an array of daemons to load in a multi-user runlevel, and some
dependencies between them.

This patch enables this behaviour in SystemD (only when compiled with
Arch support), which allows SystemD to be a drop in replacement on Arch
(modulo some minor bugs).

v2: simplified after suggestion from Lennart

1 files changed, 66 insertions, 0 deletions

diff --git a/src/service.c b/src/service.c
index df0d400240..51a7e6b20f 100644
--- a/src/service.c
+++ b/src/service.c
@@ -231,6 +231,11 @@ static char *sysv_translate_name(const char *name) {
         else if (endswith(name, ".sh"))
                 /* Drop Debian-style .sh suffix */
                 strcpy(stpcpy(r, name) - 3, ".service");
+#ifdef TARGET_ARCH
+	else if (startswith(name, "@"))
+		/* Drop Arch-style background prefix */
+		strcpy(stpcpy(r, name + 1), ".service");
+#endif
         else
                 /* Normal init scripts */
                 strcpy(stpcpy(r, name), ".service");
@@ -2658,9 +2663,66 @@ static int service_enumerate(Manager *m) {
         Unit *service;
         Iterator j;
         int r;
+#ifdef TARGET_ARCH
+        Unit *previous = NULL;
+        char *arch_daemons = NULL;
+        char *arch_daemons_stripped = NULL;
+        char **arch_daemons_split = NULL;
+#endif
 
         assert(m);
 
+#ifdef TARGET_ARCH
+        if ((r = parse_env_file("/etc/rc.conf", NEWLINE,
+                                "DAEMONS", &arch_daemons,
+                                NULL)) < 0) {
+
+                if (r != -ENOENT)
+                        log_warning("Failed to read /etc/rc.conf: %s", strerror(-r));
+
+        } else if (arch_daemons) {
+                if (!(arch_daemons_stripped = strchr(arch_daemons, '(')))
+                        arch_daemons_stripped = arch_daemons;
+                else
+                        arch_daemons_stripped++; /* strip start paren */
+
+                arch_daemons_stripped[strcspn(arch_daemons_stripped, ")")] = 0; /* strip end paren */
+
+                if (!(arch_daemons_split = strv_split_quoted(arch_daemons_stripped))) {
+                        r = -ENOMEM;
+                        goto finish;
+                }
+
+                STRV_FOREACH(p, arch_daemons_split) {
+
+                        free(name);
+
+                        if (**p == '!') /* daemons prefixed with ! are disabled, so ignore them */
+                                continue;
+
+                        if (!(name = sysv_translate_name(*p))) {
+                                r = -ENOMEM;
+                                goto finish;
+                        }
+
+                        if ((r = manager_load_unit_prepare(m, name, NULL, NULL, &service)) < 0) {
+                                log_warning("Failed to prepare unit %s: %s", name, strerror(-r));
+                                continue;
+                        }
+
+                        if ((r = unit_add_two_dependencies_by_name_inverse(service, UNIT_AFTER, UNIT_WANTS, "multi-user.target", NULL, true)) < 0)
+                                goto finish;
+
+                        if (previous)
+                                if ((r = unit_add_dependency(service, UNIT_AFTER, previous, true)) < 0)
+                                        goto finish;
+
+                        if (**p != '@') /* daemons prefixed with @ can be started in the background */
+                                previous = service;
+                }
+        }
+#endif
+
         zero(runlevel_services);
 
         STRV_FOREACH(p, m->lookup_paths.sysvrcnd_path)
@@ -2798,6 +2860,10 @@ finish:
         free(path);
         free(fpath);
         free(name);
+#ifdef TARGET_ARCH
+        free(arch_daemons);
+        free(arch_daemons_split);
+#endif
 
         for (i = 0; i < ELEMENTSOF(rcnd_table); i++)
                 set_free(runlevel_services[i]);