debian: add support for update-alternative

In Ubuntu mesa EGL is using Debian Alternatives system, so that multiple EGL
implementation can be installed simultaneously in the root file system. Once we
install adreno-egl, it is configured as an 'alternative' in the group
"${DEB_HOST_MULTIARCH}_egl_conf", e.g. arm-linux-gnueabihf_egl_conf in this
specific case.

The method consists of adding a custom load configuration file in
/etc/ld.conf.so.d, which is updated when we configure the *current* alternatives.

To list all registered alternatives:

$ update-alternative --list arm-linux-gnueabihf_egl_conf

To configure which alternative should be *current*:

$ update-alternative --config arm-linux-gnueabihf_egl_conf

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>

3 files changed, 49 insertions, 0 deletions

diff --git a/debian/adreno-egl.postinst b/debian/adreno-egl.postinst
new file mode 100644
index 0000000..f96606a
--- /dev/null
+++ b/debian/adreno-egl.postinst
@@ -0,0 +1,22 @@
+#!/bin/sh
+
+set -e
+
+THIS_PACKAGE=adreno-egl
+THIS_SCRIPT=postinst
+
+case "$1" in
+  configure)
+  # Use alternatives to make it easier to switch between Mesa and 3rd party modules
+  update-alternatives --force \
+    --install /etc/ld.so.conf.d/${DEB_HOST_MULTIARCH}_EGL.conf ${DEB_HOST_MULTIARCH}_egl_conf /usr/lib/${DEB_HOST_MULTIARCH}/adreno-egl/ld.so.conf 100 \
+
+  # ldconfig needs to be run immediately as we're changing /etc/ld.so.conf.d/ with
+  # alternatives.
+  LDCONFIG_NOTRIGGER=y ldconfig
+
+esac
+
+#DEBHELPER#
+
+exit 0
diff --git a/debian/adreno-egl.preinst b/debian/adreno-egl.preinst
new file mode 100644
index 0000000..56fd1f3
--- /dev/null
+++ b/debian/adreno-egl.preinst
@@ -0,0 +1,20 @@
+#!/bin/sh
+
+set -e
+
+THIS_PACKAGE=adreno-mesa
+THIS_SCRIPT=prerm
+
+case "$1" in
+  remove)
+  # Use alternatives to make it easier to switch between Mesa and 3rd party modules
+  update-alternatives --remove ${DEB_HOST_MULTIARCH}_egl_conf /usr/lib/${DEB_HOST_MULTIARCH}/adreno-egl/ld.so.conf
+
+  # explicit ldconfig due to alternatives
+  ldconfig
+
+esac
+
+#DEBHELPER#
+
+exit 0
diff --git a/debian/rules b/debian/rules
index c642495..50ba2c6 100755
--- a/debian/rules
+++ b/debian/rules
@@ -24,6 +24,13 @@ include /usr/share/dpkg/default.mk
 override_dh_auto_build:
 	tar -xf adreno-ubuntu.tar.gz
 
+override_dh_install:
+	dh_install
+
+        # Create an ld.so.conf which says where to find libEGL, libGLES{1,2}
+	echo "/usr/lib/$(DEB_HOST_MULTIARCH)/adreno-egl" \
+        > $(CURDIR)/debian/adreno-egl/usr/lib/$(DEB_HOST_MULTIARCH)/adreno-egl/ld.so.conf
+
 override_dh_auto_clean:
 	rm -rf usr