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zhuyifei1999Alexei Starovoitov
zhuyifei1999
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Alexei Starovoitov
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selftests/bpf: Test load and dump metadata with btftool and skel
This is a simple test to check that loading and dumping metadata in btftool works, whether or not metadata contents are used by the program. A C test is also added to make sure the skeleton code can read the metadata values. Signed-off-by: YiFei Zhu <[email protected]> Signed-off-by: Stanislav Fomichev <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Cc: YiFei Zhu <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
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‎tools/testing/selftests/bpf/Makefile

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -68,7 +68,8 @@ TEST_PROGS := test_kmod.sh \
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test_tc_edt.sh \
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test_xdping.sh \
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test_bpftool_build.sh \
71-
test_bpftool.sh
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test_bpftool.sh \
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test_bpftool_metadata.sh \
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7374
TEST_PROGS_EXTENDED := with_addr.sh \
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with_tunnels.sh \

‎tools/testing/selftests/bpf/prog_tests/metadata.c

Lines changed: 141 additions & 0 deletions
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@@ -0,0 +1,141 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2020 Google LLC.
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*/
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#include <test_progs.h>
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#include <cgroup_helpers.h>
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#include <network_helpers.h>
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#include "metadata_unused.skel.h"
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#include "metadata_used.skel.h"
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static int duration;
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static int prog_holds_map(int prog_fd, int map_fd)
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{
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struct bpf_prog_info prog_info = {};
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struct bpf_prog_info map_info = {};
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__u32 prog_info_len;
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__u32 map_info_len;
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__u32 *map_ids;
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int nr_maps;
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int ret;
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int i;
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map_info_len = sizeof(map_info);
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ret = bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len);
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if (ret)
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return -errno;
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prog_info_len = sizeof(prog_info);
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ret = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &prog_info_len);
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if (ret)
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return -errno;
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map_ids = calloc(prog_info.nr_map_ids, sizeof(__u32));
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if (!map_ids)
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return -ENOMEM;
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nr_maps = prog_info.nr_map_ids;
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memset(&prog_info, 0, sizeof(prog_info));
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prog_info.nr_map_ids = nr_maps;
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prog_info.map_ids = ptr_to_u64(map_ids);
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prog_info_len = sizeof(prog_info);
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ret = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &prog_info_len);
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if (ret) {
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ret = -errno;
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goto free_map_ids;
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}
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ret = -ENOENT;
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for (i = 0; i < prog_info.nr_map_ids; i++) {
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if (map_ids[i] == map_info.id) {
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ret = 0;
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break;
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}
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}
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free_map_ids:
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free(map_ids);
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return ret;
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}
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static void test_metadata_unused(void)
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{
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struct metadata_unused *obj;
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int err;
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obj = metadata_unused__open_and_load();
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if (CHECK(!obj, "skel-load", "errno %d", errno))
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return;
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err = prog_holds_map(bpf_program__fd(obj->progs.prog),
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bpf_map__fd(obj->maps.rodata));
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if (CHECK(err, "prog-holds-rodata", "errno: %d", err))
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return;
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/* Assert that we can access the metadata in skel and the values are
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* what we expect.
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*/
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if (CHECK(strncmp(obj->rodata->bpf_metadata_a, "foo",
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sizeof(obj->rodata->bpf_metadata_a)),
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"bpf_metadata_a", "expected \"foo\", value differ"))
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goto close_bpf_object;
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if (CHECK(obj->rodata->bpf_metadata_b != 1, "bpf_metadata_b",
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"expected 1, got %d", obj->rodata->bpf_metadata_b))
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goto close_bpf_object;
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/* Assert that binding metadata map to prog again succeeds. */
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err = bpf_prog_bind_map(bpf_program__fd(obj->progs.prog),
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bpf_map__fd(obj->maps.rodata), NULL);
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CHECK(err, "rebind_map", "errno %d, expected 0", errno);
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close_bpf_object:
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metadata_unused__destroy(obj);
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}
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static void test_metadata_used(void)
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{
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struct metadata_used *obj;
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int err;
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obj = metadata_used__open_and_load();
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if (CHECK(!obj, "skel-load", "errno %d", errno))
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return;
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err = prog_holds_map(bpf_program__fd(obj->progs.prog),
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bpf_map__fd(obj->maps.rodata));
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if (CHECK(err, "prog-holds-rodata", "errno: %d", err))
112+
return;
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/* Assert that we can access the metadata in skel and the values are
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* what we expect.
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*/
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if (CHECK(strncmp(obj->rodata->bpf_metadata_a, "bar",
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sizeof(obj->rodata->bpf_metadata_a)),
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"metadata_a", "expected \"bar\", value differ"))
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goto close_bpf_object;
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if (CHECK(obj->rodata->bpf_metadata_b != 2, "metadata_b",
122+
"expected 2, got %d", obj->rodata->bpf_metadata_b))
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goto close_bpf_object;
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/* Assert that binding metadata map to prog again succeeds. */
126+
err = bpf_prog_bind_map(bpf_program__fd(obj->progs.prog),
127+
bpf_map__fd(obj->maps.rodata), NULL);
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CHECK(err, "rebind_map", "errno %d, expected 0", errno);
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close_bpf_object:
131+
metadata_used__destroy(obj);
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}
133+
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void test_metadata(void)
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{
136+
if (test__start_subtest("unused"))
137+
test_metadata_unused();
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139+
if (test__start_subtest("used"))
140+
test_metadata_used();
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}

‎tools/testing/selftests/bpf/progs/metadata_unused.c

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@@ -0,0 +1,15 @@
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// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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volatile const char bpf_metadata_a[] SEC(".rodata") = "foo";
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volatile const int bpf_metadata_b SEC(".rodata") = 1;
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SEC("cgroup_skb/egress")
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int prog(struct xdp_md *ctx)
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{
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return 0;
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}
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15+
char _license[] SEC("license") = "GPL";

‎tools/testing/selftests/bpf/progs/metadata_used.c

Lines changed: 15 additions & 0 deletions
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@@ -0,0 +1,15 @@
1+
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/bpf.h>
4+
#include <bpf/bpf_helpers.h>
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volatile const char bpf_metadata_a[] SEC(".rodata") = "bar";
7+
volatile const int bpf_metadata_b SEC(".rodata") = 2;
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9+
SEC("cgroup_skb/egress")
10+
int prog(struct xdp_md *ctx)
11+
{
12+
return bpf_metadata_b ? 1 : 0;
13+
}
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15+
char _license[] SEC("license") = "GPL";

‎tools/testing/selftests/bpf/test_bpftool_metadata.sh

Lines changed: 82 additions & 0 deletions
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@@ -0,0 +1,82 @@
1+
#!/bin/sh
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# SPDX-License-Identifier: GPL-2.0
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4+
# Kselftest framework requirement - SKIP code is 4.
5+
ksft_skip=4
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7+
TESTNAME=bpftool_metadata
8+
BPF_FS=$(awk '$3 == "bpf" {print $2; exit}' /proc/mounts)
9+
BPF_DIR=$BPF_FS/test_$TESTNAME
10+
11+
_cleanup()
12+
{
13+
set +e
14+
rm -rf $BPF_DIR 2> /dev/null
15+
}
16+
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cleanup_skip()
18+
{
19+
echo "selftests: $TESTNAME [SKIP]"
20+
_cleanup
21+
22+
exit $ksft_skip
23+
}
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cleanup()
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{
27+
if [ "$?" = 0 ]; then
28+
echo "selftests: $TESTNAME [PASS]"
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else
30+
echo "selftests: $TESTNAME [FAILED]"
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fi
32+
_cleanup
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}
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35+
if [ $(id -u) -ne 0 ]; then
36+
echo "selftests: $TESTNAME [SKIP] Need root privileges"
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exit $ksft_skip
38+
fi
39+
40+
if [ -z "$BPF_FS" ]; then
41+
echo "selftests: $TESTNAME [SKIP] Could not run test without bpffs mounted"
42+
exit $ksft_skip
43+
fi
44+
45+
if ! bpftool version > /dev/null 2>&1; then
46+
echo "selftests: $TESTNAME [SKIP] Could not run test without bpftool"
47+
exit $ksft_skip
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fi
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set -e
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trap cleanup_skip EXIT
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54+
mkdir $BPF_DIR
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56+
trap cleanup EXIT
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58+
bpftool prog load metadata_unused.o $BPF_DIR/unused
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60+
METADATA_PLAIN="$(bpftool prog)"
61+
echo "$METADATA_PLAIN" | grep 'a = "foo"' > /dev/null
62+
echo "$METADATA_PLAIN" | grep 'b = 1' > /dev/null
63+
64+
bpftool prog --json | grep '"metadata":{"a":"foo","b":1}' > /dev/null
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66+
bpftool map | grep 'metadata.rodata' > /dev/null
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68+
rm $BPF_DIR/unused
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70+
bpftool prog load metadata_used.o $BPF_DIR/used
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METADATA_PLAIN="$(bpftool prog)"
73+
echo "$METADATA_PLAIN" | grep 'a = "bar"' > /dev/null
74+
echo "$METADATA_PLAIN" | grep 'b = 2' > /dev/null
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bpftool prog --json | grep '"metadata":{"a":"bar","b":2}' > /dev/null
77+
78+
bpftool map | grep 'metadata.rodata' > /dev/null
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80+
rm $BPF_DIR/used
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exit 0

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