Commit 45c5589d authored by Quentin Monnet's avatar Quentin Monnet Committed by Daniel Borkmann

tools: bpftool: improve and check builds for different make invocations

There are a number of alternative "make" invocations that can be used to
compile bpftool. The following invocations are expected to work:

  - through the kbuild system, from the top of the repository
    (make tools/bpf)
  - by telling make to change to the bpftool directory
    (make -C tools/bpf/bpftool)
  - by building the BPF tools from tools/
    (cd tools && make bpf)
  - by running make from bpftool directory
    (cd tools/bpf/bpftool && make)

Additionally, setting the O or OUTPUT variables should tell the build
system to use a custom output path, for each of these alternatives.

The following patch fixes the following invocations:

  $ make tools/bpf
  $ make tools/bpf O=<dir>
  $ make -C tools/bpf/bpftool OUTPUT=<dir>
  $ make -C tools/bpf/bpftool O=<dir>
  $ cd tools/ && make bpf O=<dir>
  $ cd tools/bpf/bpftool && make OUTPUT=<dir>
  $ cd tools/bpf/bpftool && make O=<dir>

After this commit, the build still fails for two variants when passing
the OUTPUT variable:

  $ make tools/bpf OUTPUT=<dir>
  $ cd tools/ && make bpf OUTPUT=<dir>

In order to remember and check what make invocations are supposed to
work, and to document the ones which do not, a new script is added to
the BPF selftests. Note that some invocations require the kernel to be
configured, so the script skips them if no .config file is found.

v2:
- In make_and_clean(), set $ERROR to 1 when "make" returns non-zero,
  even if the binary was produced.
- Run "make clean" from the correct directory (bpf/ instead of bpftool/,
  when relevant).
Reported-by: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarQuentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent e0a43aa3
......@@ -17,21 +17,23 @@ endif
BPF_DIR = $(srctree)/tools/lib/bpf/
ifneq ($(OUTPUT),)
BPF_PATH = $(OUTPUT)
LIBBPF_OUTPUT = $(OUTPUT)/libbpf/
LIBBPF_PATH = $(LIBBPF_OUTPUT)
else
BPF_PATH = $(BPF_DIR)
LIBBPF_PATH = $(BPF_DIR)
endif
LIBBPF = $(BPF_PATH)libbpf.a
LIBBPF = $(LIBBPF_PATH)libbpf.a
BPFTOOL_VERSION := $(shell make -rR --no-print-directory -sC ../../.. kernelversion)
$(LIBBPF): FORCE
$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(OUTPUT) $(OUTPUT)libbpf.a
$(if $(LIBBPF_OUTPUT),@mkdir -p $(LIBBPF_OUTPUT))
$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_OUTPUT) $(LIBBPF_OUTPUT)libbpf.a
$(LIBBPF)-clean:
$(call QUIET_CLEAN, libbpf)
$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(OUTPUT) clean >/dev/null
$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_OUTPUT) clean >/dev/null
prefix ?= /usr/local
bash_compdir ?= /usr/share/bash-completion/completions
......
......@@ -63,7 +63,8 @@ TEST_PROGS := test_kmod.sh \
test_tcp_check_syncookie.sh \
test_tc_tunnel.sh \
test_tc_edt.sh \
test_xdping.sh
test_xdping.sh \
test_bpftool_build.sh
TEST_PROGS_EXTENDED := with_addr.sh \
with_tunnels.sh \
......
#!/bin/bash
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
ERROR=0
TMPDIR=
# If one build fails, continue but return non-0 on exit.
return_value() {
if [ -d "$TMPDIR" ] ; then
rm -rf -- $TMPDIR
fi
exit $ERROR
}
trap return_value EXIT
case $1 in
-h|--help)
echo -e "$0 [-j <n>]"
echo -e "\tTest the different ways of building bpftool."
echo -e ""
echo -e "\tOptions:"
echo -e "\t\t-j <n>:\tPass -j flag to 'make'."
exit
;;
esac
J=$*
# Assume script is located under tools/testing/selftests/bpf/. We want to start
# build attempts from the top of kernel repository.
SCRIPT_REL_PATH=$(realpath --relative-to=$PWD $0)
SCRIPT_REL_DIR=$(dirname $SCRIPT_REL_PATH)
KDIR_ROOT_DIR=$(realpath $PWD/$SCRIPT_REL_DIR/../../../../)
cd $KDIR_ROOT_DIR
check() {
local dir=$(realpath $1)
echo -n "binary: "
# Returns non-null if file is found (and "false" is run)
find $dir -type f -executable -name bpftool -print -exec false {} + && \
ERROR=1 && printf "FAILURE: Did not find bpftool\n"
}
make_and_clean() {
echo -e "\$PWD: $PWD"
echo -e "command: make -s $* >/dev/null"
make $J -s $* >/dev/null
if [ $? -ne 0 ] ; then
ERROR=1
fi
if [ $# -ge 1 ] ; then
check ${@: -1}
else
check .
fi
(
if [ $# -ge 1 ] ; then
cd ${@: -1}
fi
make -s clean
)
echo
}
make_with_tmpdir() {
local ARGS
TMPDIR=$(mktemp -d)
if [ $# -ge 2 ] ; then
ARGS=${@:1:(($# - 1))}
fi
echo -e "\$PWD: $PWD"
echo -e "command: make -s $ARGS ${@: -1}=$TMPDIR/ >/dev/null"
make $J -s $ARGS ${@: -1}=$TMPDIR/ >/dev/null
if [ $? -ne 0 ] ; then
ERROR=1
fi
check $TMPDIR
rm -rf -- $TMPDIR
echo
}
echo "Trying to build bpftool"
echo -e "... through kbuild\n"
if [ -f ".config" ] ; then
make_and_clean tools/bpf
## $OUTPUT is overwritten in kbuild Makefile, and thus cannot be passed
## down from toplevel Makefile to bpftool's Makefile.
# make_with_tmpdir tools/bpf OUTPUT
echo -e "skip: make tools/bpf OUTPUT=<dir> (not supported)\n"
make_with_tmpdir tools/bpf O
else
echo -e "skip: make tools/bpf (no .config found)\n"
echo -e "skip: make tools/bpf OUTPUT=<dir> (not supported)\n"
echo -e "skip: make tools/bpf O=<dir> (no .config found)\n"
fi
echo -e "... from kernel source tree\n"
make_and_clean -C tools/bpf/bpftool
make_with_tmpdir -C tools/bpf/bpftool OUTPUT
make_with_tmpdir -C tools/bpf/bpftool O
echo -e "... from tools/\n"
cd tools/
make_and_clean bpf
## In tools/bpf/Makefile, function "descend" is called and passes $(O) and
## $(OUTPUT). We would like $(OUTPUT) to have "bpf/bpftool/" appended before
## calling bpftool's Makefile, but this is not the case as the "descend"
## function focuses on $(O)/$(subdir). However, in the present case, updating
## $(O) to have $(OUTPUT) recomputed from it in bpftool's Makefile does not
## work, because $(O) is not defined from command line and $(OUTPUT) is not
## updated in tools/scripts/Makefile.include.
##
## Workarounds would require to a) edit "descend" or use an alternative way to
## call bpftool's Makefile, b) modify the conditions to update $(OUTPUT) and
## other variables in tools/scripts/Makefile.include (at the risk of breaking
## the build of other tools), or c) append manually the "bpf/bpftool" suffix to
## $(OUTPUT) in bpf's Makefile, which may break if targets for other directories
## use "descend" in the future.
# make_with_tmpdir bpf OUTPUT
echo -e "skip: make bpf OUTPUT=<dir> (not supported)\n"
make_with_tmpdir bpf O
echo -e "... from bpftool's dir\n"
cd bpf/bpftool
make_and_clean
make_with_tmpdir OUTPUT
make_with_tmpdir O
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