Re: [PATCH kmod v5 5/5] libkmod, depmod, modprobe: Make directory for kernel modules configurable

From: Lucas De Marchi
Date: Tue Oct 17 2023 - 13:50:46 EST


On Tue, Jul 18, 2023 at 02:01:56PM +0200, Michal Suchanek wrote:
Now that modprobe.d is searched under ${prefix}/lib, allow a complete
transition to files only under ${prefix} by adding a ${module_directory}
configuration. This specifies the directory where to search for kernel
modules and should match the location where the kernel/distro installs
them.

With this distributions that do not want to ship files in /lib can also
move kernel modules to /usr while others can keep them in /lib.

Signed-off-by: Michal Suchanek <msuchanek@xxxxxxx>
---
v4: Make the whole path configurable
v5: More verbose commit message
---
Makefile.am | 3 +-
configure.ac | 7 ++
libkmod/libkmod.c | 4 +-
man/Makefile.am | 1 +
man/depmod.d.xml | 6 +-
man/depmod.xml | 4 +-
man/modinfo.xml | 2 +-
man/modprobe.xml | 2 +-
man/modules.dep.xml | 6 +-
testsuite/module-playground/Makefile | 2 +-
testsuite/setup-rootfs.sh | 109 +++++++++++++++------------
testsuite/test-depmod.c | 16 ++--
testsuite/test-testsuite.c | 8 +-
tools/depmod.c | 6 +-
tools/kmod.pc.in | 1 +
tools/modinfo.c | 4 +-
tools/modprobe.c | 4 +-
tools/static-nodes.c | 6 +-
18 files changed, 107 insertions(+), 84 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index 6d0b2decfef3..019aa749fdf1 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -20,6 +20,7 @@ AM_CPPFLAGS = \
-I$(top_srcdir) \
-DSYSCONFDIR=\""$(sysconfdir)"\" \
-DDISTCONFDIR=\""$(distconfdir)"\" \
+ -DMODULE_DIRECTORY=\""$(module_directory)"\" \
${zlib_CFLAGS}

AM_CFLAGS = $(OUR_CFLAGS)
@@ -220,7 +221,7 @@ EXTRA_DIST += testsuite/setup-rootfs.sh
MODULE_PLAYGROUND = testsuite/module-playground
ROOTFS = testsuite/rootfs
ROOTFS_PRISTINE = $(top_srcdir)/testsuite/rootfs-pristine
-CREATE_ROOTFS = $(AM_V_GEN) $(top_srcdir)/testsuite/setup-rootfs.sh $(ROOTFS_PRISTINE) $(ROOTFS) $(MODULE_PLAYGROUND) $(top_builddir)/config.h $(sysconfdir)
+CREATE_ROOTFS = $(AM_V_GEN) MODULE_DIRECTORY=$(module_directory) $(top_srcdir)/testsuite/setup-rootfs.sh $(ROOTFS_PRISTINE) $(ROOTFS) $(MODULE_PLAYGROUND) $(top_builddir)/config.h $(sysconfdir)

build-module-playground:
$(AM_V_GEN)if test "$(top_srcdir)" != "$(top_builddir)"; then \
diff --git a/configure.ac b/configure.ac
index b4584d6cdc67..4051dc9249e2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -91,6 +91,12 @@ AC_ARG_WITH([rootlibdir],
[], [with_rootlibdir=$libdir])
AC_SUBST([rootlibdir], [$with_rootlibdir])

+# Ideally this would be $prefix/lib/modules but default to /lib/modules for compatibility with earlier versions
+AC_ARG_WITH([module_directory],
+ AS_HELP_STRING([--with-module-directory=DIR], [directory in which to look for kernel modules - typically '/lib/modules' or '${prefix}/lib/modules']),
+ [], [with_module_directory=/lib/modules])
+AC_SUBST([module_directory], [$with_module_directory])

we will probably have "fun" results if we accept a relative path here.

+
AC_ARG_WITH([zstd],
AS_HELP_STRING([--with-zstd], [handle Zstandard-compressed modules @<:@default=disabled@:>@]),
[], [with_zstd=no])
@@ -326,6 +332,7 @@ AC_MSG_RESULT([
$PACKAGE $VERSION
=======

+ module_directory: ${module_directory}
prefix: ${prefix}
sysconfdir: ${sysconfdir}
distconfdir: ${distconfdir}
diff --git a/libkmod/libkmod.c b/libkmod/libkmod.c
index 09e6041461b0..63719e886de8 100644
--- a/libkmod/libkmod.c
+++ b/libkmod/libkmod.c
@@ -209,7 +209,7 @@ static int log_priority(const char *priority)
return 0;
}

-static const char *dirname_default_prefix = "/lib/modules";
+static const char *dirname_default_prefix = MODULE_DIRECTORY;

static char *get_kernel_release(const char *dirname)
{
@@ -231,7 +231,7 @@ static char *get_kernel_release(const char *dirname)
/**
* kmod_new:
* @dirname: what to consider as linux module's directory, if NULL
- * defaults to /lib/modules/`uname -r`. If it's relative,
+ * defaults to ${module_prefix}/lib/modules/`uname -r`. If it's relative,

module_prefix? did you mean to use $MODULE_DIRECTORY/`uname -r`?

* it's treated as relative to the current working directory.
* Otherwise, give an absolute dirname.
* @config_paths: ordered array of paths (directories or files) where
diff --git a/man/Makefile.am b/man/Makefile.am
index 2fea8e46bf2f..f550091a216a 100644
--- a/man/Makefile.am
+++ b/man/Makefile.am
@@ -22,6 +22,7 @@ CLEANFILES = $(dist_man_MANS)
else \
sed -e '/@DISTCONFDIR@/d' $< ; \
fi | \
+ sed -e 's|@MODULE_DIRECTORY@|$(module_directory)|g' | \
$(XSLT) \
-o $@ \
--nonet \
diff --git a/man/depmod.d.xml b/man/depmod.d.xml
index f282a39cc840..b07e6a2bd4fe 100644
--- a/man/depmod.d.xml
+++ b/man/depmod.d.xml
@@ -70,7 +70,7 @@
</term>
<listitem>
<para>
- This allows you to specify the order in which /lib/modules
+ This allows you to specify the order in which @MODULE_DIRECTORY@
(or other configured module location) subdirectories will
be processed by <command>depmod</command>. Directories are
listed in order, with the highest priority given to the
@@ -101,7 +101,7 @@
<command>depmod</command> command. It is possible to
specify one kernel or all kernels using the * wildcard.
<replaceable>modulesubdirectory</replaceable> is the
- name of the subdirectory under /lib/modules (or other
+ name of the subdirectory under @MODULE_DIRECTORY@ (or other
module location) where the target module is installed.
</para>
<para>
@@ -110,7 +110,7 @@
specifying the following command: "override kmod * extra".
This will ensure that any matching module name installed
under the <command>extra</command> subdirectory within
- /lib/modules (or other module location) will take priority
+ @MODULE_DIRECTORY@ (or other module location) will take priority
over any likenamed module already provided by the kernel.
</para>
</listitem>
diff --git a/man/depmod.xml b/man/depmod.xml
index 3b0097184fd7..fce2a4a67a89 100644
--- a/man/depmod.xml
+++ b/man/depmod.xml
@@ -80,7 +80,7 @@
</para>
<para> <command>depmod</command> creates a list of module dependencies by
reading each module under
- <filename>/lib/modules/</filename><replaceable>version</replaceable> and
+ <filename>@MODULE_DIRECTORY@/</filename><replaceable>version</replaceable> and
determining what symbols it exports and what symbols it needs. By
default, this list is written to <filename>modules.dep</filename>, and a
binary hashed version named <filename>modules.dep.bin</filename>, in the
@@ -141,7 +141,7 @@
<listitem>
<para>
If your modules are not currently in the (normal) directory
- <filename>/lib/modules/</filename><replaceable>version</replaceable>,
+ <filename>@MODULE_DIRECTORY@/</filename><replaceable>version</replaceable>,
but in a staging area, you can specify a
<replaceable>basedir</replaceable> which is prepended to the
directory name. This <replaceable>basedir</replaceable> is
diff --git a/man/modinfo.xml b/man/modinfo.xml
index 9fe0324a2527..b6c4d6045829 100644
--- a/man/modinfo.xml
+++ b/man/modinfo.xml
@@ -54,7 +54,7 @@
<command>modinfo</command> extracts information from the Linux Kernel
modules given on the command line. If the module name is not a filename,
then the
- <filename>/lib/modules/</filename><replaceable>version</replaceable>
+ <filename>@MODULE_DIRECTORY@/</filename><replaceable>version</replaceable>
directory is searched, as is also done by
<citerefentry><refentrytitle>modprobe</refentrytitle><manvolnum>8</manvolnum></citerefentry>
when loading kernel modules.
diff --git a/man/modprobe.xml b/man/modprobe.xml
index 91f9e27997cd..4d1fd59c000b 100644
--- a/man/modprobe.xml
+++ b/man/modprobe.xml
@@ -78,7 +78,7 @@
is no difference between _ and - in module names (automatic
underscore conversion is performed).
<command>modprobe</command> looks in the module directory
- <filename>/lib/modules/`uname -r`</filename> for all
+ <filename>@MODULE_DIRECTORY@/`uname -r`</filename> for all
the modules and other files, except for the optional
configuration files in the
<filename>/etc/modprobe.d</filename> directory
diff --git a/man/modules.dep.xml b/man/modules.dep.xml
index ed633694ec9e..8ef6d8b3536e 100644
--- a/man/modules.dep.xml
+++ b/man/modules.dep.xml
@@ -34,8 +34,8 @@
</refnamediv>

<refsynopsisdiv>
- <para><filename>/lib/modules/modules.dep</filename></para>
- <para><filename>/lib/modules/modules.dep.bin</filename></para>
+ <para><filename>@MODULE_DIRECTORY@/modules.dep</filename></para>
+ <para><filename>@MODULE_DIRECTORY@/modules.dep.bin</filename></para>
</refsynopsisdiv>

<refsect1><title>DESCRIPTION</title>
@@ -43,7 +43,7 @@
<filename>modules.dep.bin</filename> is a binary file generated by
<command>depmod</command> listing the dependencies for
every module in the directories under
- <filename>/lib/modules/</filename><replaceable>version</replaceable>.
+ <filename>@MODULE_DIRECTORY@/</filename><replaceable>version</replaceable>.
It is used by kmod tools such as <command>modprobe</command> and
libkmod.
</para>
diff --git a/testsuite/module-playground/Makefile b/testsuite/module-playground/Makefile
index e6045b0dd932..a7ab09bea2bf 100644
--- a/testsuite/module-playground/Makefile
+++ b/testsuite/module-playground/Makefile
@@ -47,7 +47,7 @@ endif

else
# normal makefile
-KDIR ?= /lib/modules/`uname -r`/build
+KDIR ?= $(module_prefix)/lib/modules/`uname -r`/build
KVER ?= `uname -r`
ifeq ($(FAKE_BUILD),)
FAKE_BUILD=0
diff --git a/testsuite/setup-rootfs.sh b/testsuite/setup-rootfs.sh
index 4440ddcd6b4d..a780f9381b3c 100755
--- a/testsuite/setup-rootfs.sh
+++ b/testsuite/setup-rootfs.sh
@@ -16,6 +16,19 @@ create_rootfs() {
cp -r "$ROOTFS_PRISTINE" "$ROOTFS"
find "$ROOTFS" -type d -exec chmod +w {} \;
find "$ROOTFS" -type f -name .gitignore -exec rm -f {} \;
+ if [ "$MODULE_DIRECTORY" != "/lib/modules" ] ; then
+ sed -i -e "s|/lib/modules|$MODULE_DIRECTORY|g" $(find "$ROOTFS" -name \*.txt -o -name \*.conf -o -name \*.dep)
+ sed -i -e "s|$MODULE_DIRECTORY/external|/lib/modules/external|g" $(find "$ROOTFS" -name \*.txt -o -name \*.conf -o -name \*.dep)
+ for i in "$ROOTFS"/*/lib/modules/* "$ROOTFS"/*/*/lib/modules/* ; do
+ version="$(basename $i)"
+ [ $version != 'external' ] || continue
+ mod="$(dirname $i)"
+ lib="$(dirname $mod)"
+ up="$(dirname $lib)$MODULE_DIRECTORY"
+ mkdir -p "$up"
+ mv "$i" "$up"
+ done
+ fi

if [ "$SYSCONFDIR" != "/etc" ]; then
find "$ROOTFS" -type d -name etc -printf "%h\n" | while read -r e; do
@@ -32,57 +45,57 @@ feature_enabled() {

declare -A map
map=(
- ["test-depmod/search-order-simple/lib/modules/4.4.4/kernel/crypto/"]="mod-simple.ko"
- ["test-depmod/search-order-simple/lib/modules/4.4.4/updates/"]="mod-simple.ko"
- ["test-depmod/search-order-same-prefix/lib/modules/4.4.4/foo/"]="mod-simple.ko"
- ["test-depmod/search-order-same-prefix/lib/modules/4.4.4/foobar/"]="mod-simple.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-a.ko"]="mod-loop-a.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-b.ko"]="mod-loop-b.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-c.ko"]="mod-loop-c.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-d.ko"]="mod-loop-d.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-e.ko"]="mod-loop-e.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-f.ko"]="mod-loop-f.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-g.ko"]="mod-loop-g.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-h.ko"]="mod-loop-h.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-i.ko"]="mod-loop-i.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-j.ko"]="mod-loop-j.ko"
- ["test-depmod/detect-loop/lib/modules/4.4.4/kernel/mod-loop-k.ko"]="mod-loop-k.ko"
- ["test-depmod/search-order-external-first/lib/modules/4.4.4/foo/"]="mod-simple.ko"
- ["test-depmod/search-order-external-first/lib/modules/4.4.4/foobar/"]="mod-simple.ko"
+ ["test-depmod/search-order-simple$MODULE_DIRECTORY/4.4.4/kernel/crypto/"]="mod-simple.ko"
+ ["test-depmod/search-order-simple$MODULE_DIRECTORY/4.4.4/updates/"]="mod-simple.ko"
+ ["test-depmod/search-order-same-prefix$MODULE_DIRECTORY/4.4.4/foo/"]="mod-simple.ko"
+ ["test-depmod/search-order-same-prefix$MODULE_DIRECTORY/4.4.4/foobar/"]="mod-simple.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-a.ko"]="mod-loop-a.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-b.ko"]="mod-loop-b.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-c.ko"]="mod-loop-c.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-d.ko"]="mod-loop-d.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-e.ko"]="mod-loop-e.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-f.ko"]="mod-loop-f.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-g.ko"]="mod-loop-g.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-h.ko"]="mod-loop-h.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-i.ko"]="mod-loop-i.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-j.ko"]="mod-loop-j.ko"
+ ["test-depmod/detect-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-k.ko"]="mod-loop-k.ko"
+ ["test-depmod/search-order-external-first$MODULE_DIRECTORY/4.4.4/foo/"]="mod-simple.ko"
+ ["test-depmod/search-order-external-first$MODULE_DIRECTORY/4.4.4/foobar/"]="mod-simple.ko"
["test-depmod/search-order-external-first/lib/modules/external/"]="mod-simple.ko"

why didn't you change it here?

- ["test-depmod/search-order-external-last/lib/modules/4.4.4/foo/"]="mod-simple.ko"
- ["test-depmod/search-order-external-last/lib/modules/4.4.4/foobar/"]="mod-simple.ko"
+ ["test-depmod/search-order-external-last$MODULE_DIRECTORY/4.4.4/foo/"]="mod-simple.ko"
+ ["test-depmod/search-order-external-last$MODULE_DIRECTORY/4.4.4/foobar/"]="mod-simple.ko"
["test-depmod/search-order-external-last/lib/modules/external/"]="mod-simple.ko"

and here...


Otherwise looks good to me.

Pushed the first 4 patches.

thanks
Lucas De Marchi