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: Lorenz Bauer <[email protected]>
Signed-off-by: Quentin Monnet <[email protected]>
Reviewed-by: Jakub Kicinski <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
This commit is contained in:
Quentin Monnet 2019-08-30 12:00:38 +01:00 • committed by Daniel Borkmann
commit 45c5589d07
3 changed files with 152 additions and 6 deletions

View file

@ -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