[PATCH v5] depmod: Handle installing modules under a prefix

[Michal Suchanek]

Some distributions aim at shipping all files in /usr.

The path under which kernel modules are installed is hardcoded to /lib
which conflicts with this goal.

When kmod provides the config command, use it to determine the correct
module installation path.

With kmod that does not provide the config command /lib/modules is used
as before.

Signed-off-by: Michal Suchanek <msuchanek@xxxxxxx>
---
v2: Avoid error on systems with kmod that does not support config
command
v3: More verbose commit message
v4:
  - Document jq requirement
  - fix bashism
  - Update to getting full module path, not just additional prefix
v5: switch to pkgconfig
---
 Makefile          | 4 +++-
 scripts/depmod.sh | 8 ++++----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 47690c28456a..1620d224ad9c 100644
--- a/Makefile
+++ b/Makefile
@@ -1165,7 +1165,9 @@ export INSTALL_DTBS_PATH ?= $(INSTALL_PATH)/dtbs/$(KERNELRELEASE)
 # makefile but the argument can be passed to make if needed.
 #
 
-MODLIB	= $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
+export KERNEL_MODULE_DIRECTORY := $(shell pkg-config --print-variables kmod 2>/dev/null | grep '^module_directory$$' >/dev/null && pkg-config --variable=module_directory kmod || echo /lib/modules)
+
+MODLIB	= $(INSTALL_MOD_PATH)$(KERNEL_MODULE_DIRECTORY)/$(KERNELRELEASE)
 export MODLIB
 
 PHONY += prepare0
diff --git a/scripts/depmod.sh b/scripts/depmod.sh
index 3643b4f896ed..06961f990fcb 100755
--- a/scripts/depmod.sh
+++ b/scripts/depmod.sh
@@ -27,16 +27,16 @@ fi
 # numbers, so we cheat with a symlink here
 depmod_hack_needed=true
 tmp_dir=$(mktemp -d ${TMPDIR:-/tmp}/depmod.XXXXXX)
-mkdir -p "$tmp_dir/lib/modules/$KERNELRELEASE"
+mkdir -p "$tmp_dir$KERNEL_MODULE_DIRECTORY/$KERNELRELEASE"
 if "$DEPMOD" -b "$tmp_dir" $KERNELRELEASE 2>/dev/null; then
-	if test -e "$tmp_dir/lib/modules/$KERNELRELEASE/modules.dep" -o \
-		-e "$tmp_dir/lib/modules/$KERNELRELEASE/modules.dep.bin"; then
+	if test -e "$tmp_dir$KERNEL_MODULE_DIRECTORY/$KERNELRELEASE/modules.dep" -o \
+		-e "$tmp_dir$KERNEL_MODULE_DIRECTORY/$KERNELRELEASE/modules.dep.bin"; then
 		depmod_hack_needed=false
 	fi
 fi
 rm -rf "$tmp_dir"
 if $depmod_hack_needed; then
-	symlink="$INSTALL_MOD_PATH/lib/modules/99.98.$KERNELRELEASE"
+	symlink="$INSTALL_MOD_PATH$KERNEL_MODULE_DIRECTORY/99.98.$KERNELRELEASE"
 	ln -s "$KERNELRELEASE" "$symlink"
 	KERNELRELEASE=99.98.$KERNELRELEASE
 fi
-- 
2.41.0