librc: move system detection code into rc_sys and use it

This fixes an issue where librc code was calling code that only existed
in the rc binary.

This reverts commits 8addd79 and 9f6e056

This fixes #75.

2 files changed, 70 insertions, 32 deletions

diff --git a/src/librc/librc-depend.c b/src/librc/librc-depend.c
index 991a871f..d64b2b2a 100644
--- a/src/librc/librc-depend.c
+++ b/src/librc/librc-depend.c
@@ -740,7 +740,7 @@ rc_deptree_update(void)
 	char *depend, *depends, *service, *type, *nosys, *onosys;
 	size_t i, k, l;
 	bool retval = true;
-	const char *sys = NULL;
+	const char *sys = rc_sys();
 	struct utsname uts;
 
 	/* Some init scripts need RC_LIBEXECDIR to source stuff
@@ -847,9 +847,6 @@ rc_deptree_update(void)
 
 	/* Phase 2 - if we're a special system, remove services that don't
 	 * work for them. This doesn't stop them from being run directly. */
-	sys = detect_container();
-		if (!sys)
-			sys = detect_vm();
 	if (sys) {
 		len = strlen(sys);
 		nosys = xmalloc(len + 2);
diff --git a/src/librc/librc.c b/src/librc/librc.c
index 64498982..5cf4898f 100644
--- a/src/librc/librc.c
+++ b/src/librc/librc.c
@@ -198,13 +198,9 @@ found:
 #endif
 
 
-const char *
-rc_sys(void)
+static const char *
+get_systype(void)
 {
-#ifdef PREFIX
-	return RC_SYS_PREFIX;
-#endif
-
 	char *systype = rc_conf_value("rc_sys");
 	if (systype) {
 		char *s = systype;
@@ -215,7 +211,22 @@ rc_sys(void)
 			s++;
 		}
 	}
+	return systype;
+}
+
+static const char *
+detect_prefix(const char *systype)
+{
+#ifdef PREFIX
+	return RC_SYS_PREFIX;
+#else
+	return NULL;
+#endif
+}
 
+static const char *
+detect_container(const char *systype)
+{
 #ifdef __FreeBSD__
 	if (systype && strcmp(systype, RC_SYS_JAIL) == 0)
 		return RC_SYS_JAIL;
@@ -227,25 +238,8 @@ rc_sys(void)
 			return RC_SYS_JAIL;
 #endif
 
-#ifdef __NetBSD__
-	if (systype) {
-		if(strcmp(systype, RC_SYS_XEN0) == 0)
-				return RC_SYS_XEN0;
-		if (strcmp(systype, RC_SYS_XENU) == 0)
-			return RC_SYS_XENU;
-	}
-	if (exists("/kern/xen/privcmd"))
-		return RC_SYS_XEN0;
-	if (exists("/kern/xen"))
-		return RC_SYS_XENU;
-#endif
-
 #ifdef __linux__
 	if (systype) {
-		if (strcmp(systype, RC_SYS_XEN0) == 0)
-			return RC_SYS_XEN0;
-		if (strcmp(systype, RC_SYS_XENU) == 0)
-			return RC_SYS_XENU;
 		if (strcmp(systype, RC_SYS_UML) == 0)
 			return RC_SYS_UML;
 		if (strcmp(systype, RC_SYS_VSERVER) == 0)
@@ -261,11 +255,7 @@ rc_sys(void)
 		if (strcmp(systype, RC_SYS_DOCKER) == 0)
 				return RC_SYS_DOCKER;
 	}
-	if (exists("/proc/xen")) {
-		if (file_regex("/proc/xen/capabilities", "control_d"))
-			return RC_SYS_XEN0;
-		return RC_SYS_XENU;
-	} else if (file_regex("/proc/cpuinfo", "UML"))
+	if (file_regex("/proc/cpuinfo", "UML"))
 		return RC_SYS_UML;
 	else if (file_regex("/proc/self/status",
 		"(s_context|VxID):[[:space:]]*[1-9]"))
@@ -287,6 +277,57 @@ rc_sys(void)
 
 	return NULL;
 }
+
+static const char *
+detect_vm(const char *systype)
+{
+#ifdef __NetBSD__
+	if (systype) {
+		if (strcmp(systype, RC_SYS_XEN0) == 0)
+			return RC_SYS_XEN0;
+		if (strcmp(systype, RC_SYS_XENU) == 0)
+			return RC_SYS_XENU;
+	}
+	if (exists("/kern/xen/privcmd"))
+		return RC_SYS_XEN0;
+	if (exists("/kern/xen"))
+		return RC_SYS_XENU;
+#endif
+
+#ifdef __linux__
+	if (systype) {
+		if (strcmp(systype, RC_SYS_XEN0) == 0)
+			return RC_SYS_XEN0;
+		if (strcmp(systype, RC_SYS_XENU) == 0)
+			return RC_SYS_XENU;
+	}
+	if (exists("/proc/xen")) {
+		if (file_regex("/proc/xen/capabilities", "control_d"))
+			return RC_SYS_XEN0;
+		return RC_SYS_XENU;
+	}
+#endif
+
+	return NULL;
+}
+
+const char *
+rc_sys(void)
+{
+	const char *systype;
+	const char *sys;
+
+	systype = get_systype();
+	sys = detect_prefix(systype);
+	if (!sys) {
+		sys = detect_container(systype);
+		if (!sys) {
+			sys = detect_vm(systype);
+		}
+	}
+
+	return sys;
+}
 librc_hidden_def(rc_sys)
 
 static const char *