Hangbin Liu [off-list ref] writes:
This patch adds a check to see if we support libbpf. By default the
system libbpf will be used, but static linking against a custom libbpf
version can be achieved by passing LIBBPF_DIR to configure. FORCE_LIBBPF
can be set to force configure to abort if no suitable libbpf is found,
which is useful for automatic packaging that wants to enforce the
dependency.
Signed-off-by: Hangbin Liu <redacted>
With one nit below, feel free to add back my:
Reviewed-by: Toke Høiland-Jørgensen <redacted>
quoted hunk ↗ jump to hunk
---
v3:
Check function bpf_program__section_name() separately and only use it
on higher libbpf version.
v2:
No update
---
configure | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 94 insertions(+)
diff --git a/configure b/configure
index 307912aa..58a7176e 100755
--- a/configure
+++ b/configure
@@ -240,6 +240,97 @@ check_elf()
fi
}
+have_libbpf_basic()
+{
+ cat >$TMPDIR/libbpf_test.c <<EOF
+#include <bpf/libbpf.h>
+int main(int argc, char **argv) {
+ bpf_program__set_autoload(NULL, false);
+ bpf_map__ifindex(NULL);
+ bpf_map__set_pin_path(NULL, NULL);
+ bpf_object__open_file(NULL, NULL);
+ return 0;
+}
+EOF
+
+ $CC -o $TMPDIR/libbpf_test $TMPDIR/libbpf_test.c $LIBBPF_CFLAGS $LIBBPF_LDLIBS >/dev/null 2>&1
+ local ret=$?
+
+ rm -f $TMPDIR/libbpf_test.c $TMPDIR/libbpf_test
+ return $ret
+}
+
+have_libbpf_sec_name()
+{
+ cat >$TMPDIR/libbpf_sec_test.c <<EOF
+#include <bpf/libbpf.h>
+int main(int argc, char **argv) {
+ void *ptr;
+ bpf_program__section_name(NULL);
+ return 0;
+}
+EOF
+
+ $CC -o $TMPDIR/libbpf_sec_test $TMPDIR/libbpf_sec_test.c $LIBBPF_CFLAGS $LIBBPF_LDLIBS >/dev/null 2>&1
+ local ret=$?
+
+ rm -f $TMPDIR/libbpf_sec_test.c $TMPDIR/libbpf_sec_test
+ return $ret
+}
+
+check_force_libbpf()
+{
+ # if set FORCE_LIBBPF but no libbpf support, just exist the config
+ # process to make sure we don't build without libbpf.
+ if [ -n "$FORCE_LIBBPF" ]; then
+ echo "FORCE_LIBBPF set, but couldn't find a usable libbpf"
+ exit 1
+ fi
+}
+
+check_libbpf()
+{
+ if ! ${PKG_CONFIG} libbpf --exists && [ -z "$LIBBPF_DIR" ] ; then
+ echo "no"
+ check_force_libbpf
+ return
+ fi
+
+ if [ $(uname -m) == x86_64 ]; then
+ local LIBSUBDIR=lib64
+ else
+ local LIBSUBDIR=lib
+ fi
+
+ if [ -n "$LIBBPF_DIR" ]; then
+ LIBBPF_CFLAGS="-I${LIBBPF_DIR}/include -L${LIBBPF_DIR}/${LIBSUBDIR}"
+ LIBBPF_LDLIBS="${LIBBPF_DIR}/${LIBSUBDIR}/libbpf.a -lz -lelf"
+ else
+ LIBBPF_CFLAGS=$(${PKG_CONFIG} libbpf --cflags)
+ LIBBPF_LDLIBS=$(${PKG_CONFIG} libbpf --libs)
+ fi
+
+ if ! have_libbpf_basic; then
+ echo "no"
+ echo " libbpf version is too low, please update it to at least 0.1.0"
+ check_force_libbpf
+ return
+ else
+ echo "HAVE_LIBBPF:=y" >>$CONFIG
+ echo 'CFLAGS += -DHAVE_LIBBPF ' $LIBBPF_CFLAGS >> $CONFIG
+ echo 'LDLIBS += ' $LIBBPF_LDLIBS >>$CONFIG
+ fi
+
+ # bpf_program__title() is deprecated since libbpf 0.2.0, use
+ # bpf_program__section_name() instead if we support
+ if have_libbpf_sec_name; then
+ echo "HAVE_LIBBPF_SECTION_NAME:=y" >>$CONFIG
+ echo 'CFLAGS += -DHAVE_LIBBPF_SECTION_NAME ' $LIBBPF_CFLAGS >> $CONFIG
You already added $LIBBPF_CFLAGS above, so with this it ends up being
duplicated, doesn't it?
-Toke