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Fix Linux kernel directories detection
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Most modern Linux distributions have separate locations for bare
source and prebuilt ("build") files. Additionally, there are `source`
and `build` symlinks in `/lib/modules/$(KERNEL_VERSION)` pointing to
them. The order of directory search is now:
- `configure` command line values if both `--with-linux` and
  `--with-linux-obj` were defined
- If only `--with-linux` was defined, `--with-linux-obj` is assumed
  to have the same value as `--with-linux`
- If neither `--with-linux` nor `--with-linux-obj` were defined
  autodetection is used:
  - `/lib/modules/$(uname -r)/{source,build}` respectively, if exist
  - The first directory in `/lib/modules` with the highest version
    number according to `sort -V` which contains `source` and `build`
    symlinks/directories
  - The first directory matching `/usr/src/kernels/*` and
    `/usr/src/linux-*` with the highest version number according to
    `sort -V`. Here the source and prebuilt directories are assumed
    to be the same.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: szubersk <[email protected]>
Closes #9935
Closes #13096
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@szubersk
szubersk authored Feb 16, 2022
1 parent 52a36bd commit 72f3c8b
Showing 1 changed file with 75 additions and 30 deletions.
105 changes: 75 additions & 30 deletions config/kernel.m4
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Original file line number Diff line number Diff line change
Expand Up @@ -280,6 +280,35 @@ AC_DEFUN([ZFS_AC_MODULE_SYMVERS], [
dnl #
dnl # Detect the kernel to be built against
dnl #
dnl # Most modern Linux distributions have separate locations for bare
dnl # source (source) and prebuilt (build) files. Additionally, there are
dnl # `source` and `build` symlinks in `/lib/modules/$(KERNEL_VERSION)`
dnl # pointing to them. The directory search order is now:
dnl #
dnl # - `configure` command line values if both `--with-linux` and
dnl # `--with-linux-obj` were defined
dnl #
dnl # - If only `--with-linux` was defined, `--with-linux-obj` is assumed
dnl # to have the same value as `--with-linux`
dnl #
dnl # - If neither `--with-linux` nor `--with-linux-obj` were defined
dnl # autodetection is used:
dnl #
dnl # - `/lib/modules/$(uname -r)/{source,build}` respectively, if exist.
dnl #
dnl # - If only `/lib/modules/$(uname -r)/build` exists, it is assumed
dnl # to be both source and build directory.
dnl #
dnl # - The first directory in `/lib/modules` with the highest version
dnl # number according to `sort -V` which contains both `source` and
dnl # `build` symlinks/directories. If module directory contains only
dnl # `build` component, it is assumed to be both source and build
dnl # directory.
dnl #
dnl # - Last resort: the first directory matching `/usr/src/kernels/*`
dnl # and `/usr/src/linux-*` with the highest version number according
dnl # to `sort -V` is assumed to be both source and build directory.
dnl #
AC_DEFUN([ZFS_AC_KERNEL], [
AC_ARG_WITH([linux],
AS_HELP_STRING([--with-linux=PATH],
Expand All @@ -291,56 +320,72 @@ AC_DEFUN([ZFS_AC_KERNEL], [
[Path to kernel build objects]),
[kernelbuild="$withval"])
AC_MSG_CHECKING([kernel source directory])
AS_IF([test -z "$kernelsrc"], [
AS_IF([test -e "/lib/modules/$(uname -r)/source"], [
headersdir="/lib/modules/$(uname -r)/source"
sourcelink=$(readlink -f "$headersdir")
AC_MSG_CHECKING([kernel source and build directories])
AS_IF([test -n "$kernelsrc" && test -z "$kernelbuild"], [
kernelbuild="$kernelsrc"
], [test -z "$kernelsrc"], [
AS_IF([test -e "/lib/modules/$(uname -r)/source" && \
test -e "/lib/modules/$(uname -r)/build"], [
src="/lib/modules/$(uname -r)/source"
build="/lib/modules/$(uname -r)/build"
], [test -e "/lib/modules/$(uname -r)/build"], [
headersdir="/lib/modules/$(uname -r)/build"
sourcelink=$(readlink -f "$headersdir")
build="/lib/modules/$(uname -r)/build"
src="$build"
], [
sourcelink=$(ls -1d /usr/src/kernels/* \
/usr/src/linux-* \
2>/dev/null | grep -v obj | tail -1)
src=
for d in $(ls -1d /lib/modules/* 2>/dev/null | sort -Vr); do
if test -e "$d/source" && test -e "$d/build"; then
src="$d/source"
build="$d/build"
break
fi
if test -e "$d/build"; then
src="$d/build"
build="$d/build"
break
fi
done
# the least reliable method
if test -z "$src"; then
src=$(ls -1d /usr/src/kernels/* /usr/src/linux-* \
2>/dev/null | grep -v obj | sort -Vr | head -1)
build="$src"
fi
])
AS_IF([test -n "$sourcelink" && test -e ${sourcelink}], [
kernelsrc=`readlink -f ${sourcelink}`
AS_IF([test -n "$src" && test -e "$src"], [
kernelsrc=$(readlink -e "$src")
], [
kernelsrc="[Not found]"
])
AS_IF([test -n "$build" && test -e "$build"], [
kernelbuild=$(readlink -e "$build")
], [
kernelbuild="[Not found]"
])
], [
AS_IF([test "$kernelsrc" = "NONE"], [
kernsrcver=NONE
])
withlinux=yes
])
AC_MSG_RESULT([done])
AC_MSG_CHECKING([kernel source directory])
AC_MSG_RESULT([$kernelsrc])
AS_IF([test ! -d "$kernelsrc"], [
AC_MSG_CHECKING([kernel build directory])
AC_MSG_RESULT([$kernelbuild])
AS_IF([test ! -d "$kernelsrc" || test ! -d "$kernelbuild"], [
AC_MSG_ERROR([
*** Please make sure the kernel devel package for your distribution
*** is installed and then try again. If that fails, you can specify the
*** location of the kernel source with the '--with-linux=PATH' option.])
*** location of the kernel source and build with the '--with-linux=PATH' and
*** '--with-linux-obj=PATH' options respectively.])
])
AC_MSG_CHECKING([kernel build directory])
AS_IF([test -z "$kernelbuild"], [
AS_IF([test x$withlinux != xyes -a -e "/lib/modules/$(uname -r)/build"], [
kernelbuild=`readlink -f /lib/modules/$(uname -r)/build`
], [test -d ${kernelsrc}-obj/${target_cpu}/${target_cpu}], [
kernelbuild=${kernelsrc}-obj/${target_cpu}/${target_cpu}
], [test -d ${kernelsrc}-obj/${target_cpu}/default], [
kernelbuild=${kernelsrc}-obj/${target_cpu}/default
], [test -d `dirname ${kernelsrc}`/build-${target_cpu}], [
kernelbuild=`dirname ${kernelsrc}`/build-${target_cpu}
], [
kernelbuild=${kernelsrc}
])
])
AC_MSG_RESULT([$kernelbuild])
AC_MSG_CHECKING([kernel source version])
utsrelease1=$kernelbuild/include/linux/version.h
utsrelease2=$kernelbuild/include/linux/utsrelease.h
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