[Buildroot] [PATCH 1/2] package/systemd: fix getty setup

[André Erdmann]

When trying to run a buildroot system configured with
BR2_TARGET_GENERIC_GETTY_PORT="tty1" (x86_64), the boot process hangs
with the following message:
  "A start job is running for dev-tty1.device (<time> / 1min 30s)"

Replacing /etc/systemd/system/getty.target.wants/serial-getty at tty1.service
(linking to serial-getty@) with getty at tty1.service (-> getty@) fixes the issue.

This patch adds a check that "detects" the tty type by removing digits at the
end of BR2_TARGET_GENERIC_GETTY_PORT and comparing the resulting base name.
An instance of getty at service gets created if the name matches "tty",
otherwise serial-getty@ gets instantiated (as before).

So, tty1,tty2,... are created as links getty at tty1.service -> getty@,
while ttyS0, ttyAMA0, ... are created as instances of serial-getty at .

Signed-off-by: André Erdmann <dywi at mailerd.de>
---
Notes:
"ifeq (,$(filter ...))" instead of "ifeq (tty,...)" allows to extend the list
of getty@ candidates without much effort. Not sure if there are any other than
"tty", though. Probably not, because getty at service refuses to start if
/dev/tty0 is not present.
---
 package/systemd/systemd.mk | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/package/systemd/systemd.mk b/package/systemd/systemd.mk
index face849..fec96d0 100644
--- a/package/systemd/systemd.mk
+++ b/package/systemd/systemd.mk
@@ -183,12 +183,27 @@ define SYSTEMD_USERS
 	systemd-network -1 systemd-network -1 * - - - Network Manager
 endef
 
-define SYSTEMD_INSTALL_SERVICE_TTY
+define SYSTEMD_DISABLE_SERVICE_TTY1
 	rm -f $(TARGET_DIR)/etc/systemd/system/getty.target.wants/getty at tty1.service
+endef
+
+# strip_tty_name :: str -> str
+#  removes digits at the end of the given str; ttyS0 => ttyS, tty1 => tty
+SYSTEMD_STRIP_TTY_NAME = $(shell \
+	printf "%s" "$(call qstrip,$(1))" | sed -e 's=[0-9][0-9]*$$==' )
+
+ifeq (,$(filter tty,$(call SYSTEMD_STRIP_TTY_NAME,$(BR2_TARGET_GENERIC_GETTY_PORT))))
+define SYSTEMD_INSTALL_SERVICE_TTY
 	ln -fs ../../../../lib/systemd/system/serial-getty at .service $(TARGET_DIR)/etc/systemd/system/getty.target.wants/serial-getty@$(BR2_TARGET_GENERIC_GETTY_PORT).service
 endef
+else
+define SYSTEMD_INSTALL_SERVICE_TTY
+	ln -fs ../../../../lib/systemd/system/getty at .service $(TARGET_DIR)/etc/systemd/system/getty.target.wants/getty@$(BR2_TARGET_GENERIC_GETTY_PORT).service
+endef
+endif
 
 define SYSTEMD_INSTALL_INIT_SYSTEMD
+	$(SYSTEMD_DISABLE_SERVICE_TTY1)
 	$(SYSTEMD_INSTALL_SERVICE_TTY)
 	$(SYSTEMD_INSTALL_SERVICE_NETWORK)
 	$(SYSTEMD_INSTALL_SERVICE_TIMESYNC)
-- 
2.1.2