[PATCH 2/2] alsactl: systemd and udev hookup

23 Nov 2010

Add minimal systemd and udev support to alsactl so that mixer settings
are restored at boot, when sound cards are plugged in and saved on
shutdown.
This is similar to existing udev/init script solutions in various
distributions.
Note that alsactl is called both synchronously from the udev rules as
well as asynchronously at boot. This is intended, and to ensure two
things:
- At boot the asound.state file might not be readable, since it resides
  on a different file system. That means exclusively restoring sound card
  settings from udev rules will no suffice, since if the rule is
  executed at early boot (for example within udev settle) then the file
  will no be readable and cannot be restored.
- We need to ensure that applications monitoring sound cards coming and
  going (such as PA) must not get these events before the mixer settings
  have been restored. That means the mixer settings must be restored
  synchronously withing the udev rules, before the events are passed on
  to the apps.
That basically means we need to restore the settings once in udev, to
deal with sound cards becoming available during runtime. And once in
early boot to deal with coldplugged soundcards whose data files might
not have been available at time of plugging. Hence we call alsactl
twice: one from the udev rule, and once from he systemd unit file.
---
 Makefile.am                      |    3 ++
 alsactl/.gitignore               |    3 ++
 alsactl/90-alsa-restore.rules.in |    2 +
 alsactl/Makefile.am              |   46 ++++++++++++++++++++++++++++++++++++++
 alsactl/alsa-restore.service.in  |   11 +++++++++
 alsactl/alsa-store.service.in    |    9 +++++++
 configure.in                     |   17 +++++++++++--
 7 files changed, 88 insertions(+), 3 deletions(-)
 create mode 100644 alsactl/.gitignore
 create mode 100644 alsactl/90-alsa-restore.rules.in
 create mode 100644 alsactl/alsa-restore.service.in
 create mode 100644 alsactl/alsa-store.service.in

diff --git a/Makefile.am b/Makefile.am
index 9951c46..62e1ba6 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -37,3 +37,6 @@ dist-hook:
    else \
    	$(TAR) --create --verbose --file=- $(distdir) | bzip2 -c -9 > $(distdir).tar.bz2 ; \
    fi
+
+DISTCHECK_CONFIGURE_FLAGS = \
+        --with-systemdsystemunitdir=$$dc_install_base/$(systemdsystemunitdir)
diff --git a/alsactl/.gitignore b/alsactl/.gitignore
new file mode 100644
index 0000000..56ab3a2
--- /dev/null
+++ b/alsactl/.gitignore
@@ -0,0 +1,3 @@
+alsa-store.service
+alsa-restore.service
+90-alsa-restore.rules
diff --git a/alsactl/90-alsa-restore.rules.in b/alsactl/90-alsa-restore.rules.in
new file mode 100644
index 0000000..0bcee5b
--- /dev/null
+++ b/alsactl/90-alsa-restore.rules.in
@@ -0,0 +1,2 @@
+ACTION=="add", SUBSYSTEM=="sound", KERNEL=="controlC*", KERNELS=="card*", \
+        RUN+="@sbindir@/alsactl restore $attr{number}"
diff --git a/alsactl/Makefile.am b/alsactl/Makefile.am
index 359f73a..9a2d30e 100644
--- a/alsactl/Makefile.am
+++ b/alsactl/Makefile.am
@@ -10,5 +10,51 @@ EXTRA_DIST=alsactl.1 alsactl_init.xml
 alsactl_SOURCES=alsactl.c state.c utils.c init_parse.c
 noinst_HEADERS=alsactl.h list.h init_sysdeps.c init_utils_string.c init_utils_run.c init_sysfs.c
+udevrulesdir=/lib/udev/rules.d
+
+dist_udevrules_DATA = \
+	90-alsa-restore.rules
+
+if HAVE_SYSTEMD
+
+systemdsystemunit_DATA = \
+	alsa-store.service \
+	alsa-restore.service
+
+install-data-hook:
+	$(MKDIR_P) -m 0755 \
+		$(DESTDIR)$(systemdsystemunitdir)/basic.target.wants \
+		$(DESTDIR)$(systemdsystemunitdir)/shutdown.target.wants
+	( cd $(DESTDIR)$(systemdsystemunitdir)/basic.target.wants && \
+	        rm -f alsa-restore.service && \
+		$(LN_S) ../alsa-restore.service alsa-restore.service )
+	( cd $(DESTDIR)$(systemdsystemunitdir)/shutdown.target.wants && \
+	        rm -f alsa-store.service && \
+		$(LN_S) ../alsa-store.service alsa-store.service )
+
+endif
+
+edit = \
+	sed $(SED) -r 's,@sbindir@,$(sbindir),g' < $< > $@ || rm $@
+
+alsa-store.service: alsa-store.service.in
+	$(edit)
+
+alsa-restore.service: alsa-restore.service.in
+	$(edit)
+
+90-alsa-restore.rules: 90-alsa-restore.rules.in
+	$(edit)
+
+EXTRA_DIST += \
+	alsa-store.service.in \
+	alsa-restore.service.in \
+	90-alsa-restore.rules.in
+
+CLEANFILES = \
+	alsa-store.service \
+	alsa-restore.service \
+	90-alsa-restore.rules
+
 %.7: %.xml
    xmlto man $?
diff --git a/alsactl/alsa-restore.service.in b/alsactl/alsa-restore.service.in
new file mode 100644
index 0000000..e97d196
--- /dev/null
+++ b/alsactl/alsa-restore.service.in
@@ -0,0 +1,11 @@
+[Unit]
+Description=Restore Sound Card State
+DefaultDependencies=no
+After=sysinit.target
+Before=shutdown.target
+Conflicts=shutdown.target
+
+[Service]
+Type=oneshot
+ExecStart=-@sbindir@/alsactl restore
+StandardOutput=syslog
diff --git a/alsactl/alsa-store.service.in b/alsactl/alsa-store.service.in
new file mode 100644
index 0000000..0e2823c
--- /dev/null
+++ b/alsactl/alsa-store.service.in
@@ -0,0 +1,9 @@
+[Unit]
+Description=Store Sound Card State
+DefaultDependencies=no
+Before=shutdown.target
+
+[Service]
+Type=oneshot
+ExecStart=@sbindir@/alsactl store
+StandardOutput=syslog
diff --git a/configure.in b/configure.in
index 31fd581..54ea74c 100644
--- a/configure.in
+++ b/configure.in
@@ -26,6 +26,7 @@ fi
 AC_PROG_CC
 dnl AC_PROG_CXX
 AC_PROG_INSTALL
+AC_PROG_MKDIR_P
 AC_PROG_LN_S
 AM_PATH_ALSA(1.0.16)
@@ -130,7 +131,7 @@ if test x$alsamixer = xtrue; then
       CURSES_CFLAGS=`ncursesw5-config --cflags`
       curseslib="ncursesw"
     else
-      AC_CHECK_LIB(ncursesw, initscr, 
+      AC_CHECK_LIB(ncursesw, initscr,
                  [ CURSESINC='<ncurses.h>'; CURSESLIB='-lncursesw'; curseslib="ncursesw"])
     fi
     if test -n "$CURSESINC"; then
@@ -147,12 +148,12 @@ if test x$alsamixer = xtrue; then
       CURSES_CFLAGS=`ncurses5-config --cflags`
       curseslib="ncurses"
     else
-      AC_CHECK_LIB(ncurses, initscr, 
+      AC_CHECK_LIB(ncurses, initscr,
                  [ CURSESINC='<ncurses.h>'; CURSESLIB='-lncurses'; curseslib="ncurses"])
     fi
   fi
   if test "$curseslib" = "curses" -o "$curseslib" = "auto"; then
-    AC_CHECK_LIB(curses, initscr, 
+    AC_CHECK_LIB(curses, initscr,
                  [ CURSESINC='<curses.h>'; CURSESLIB='-lcurses'; curseslib="curses"])
   fi
   if test -z "$CURSESINC"; then
@@ -278,6 +279,16 @@ SAVE_UTIL_VERSION
AC_SUBST(LIBRT)
+dnl Check for systemd
+PKG_PROG_PKG_CONFIG
+AC_ARG_WITH([systemdsystemunitdir],
+        AS_HELP_STRING([--with-systemdsystemunitdir=DIR], [Directory for systemd service files]),
+        [], [with_systemdsystemunitdir=$($PKG_CONFIG --variable=systemdsystemunitdir systemd)])
+if test "x$with_systemdsystemunitdir" != xno; then
+        AC_SUBST([systemdsystemunitdir], [$with_systemdsystemunitdir])
+fi
+AM_CONDITIONAL(HAVE_SYSTEMD, [test -n "$with_systemdsystemunitdir" -a "x$with_systemdsystemunitdir" != xno ])
+
 AC_OUTPUT(Makefile alsactl/Makefile alsactl/init/Makefile \
      alsamixer/Makefile amidi/Makefile amixer/Makefile \
      m4/Makefile po/Makefile.in \
-- 
1.7.3.2


--/04w6evG8XlLl3ft--

    

[PATCH 2/2] alsactl: systemd and udev hookup

Lennart Poettering