tetragon

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// SPDX-License-Identifier: Apache-2.0
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// Copyright Authors of Tetragon
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package btf
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import (
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	"fmt"
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	"os"
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	"path/filepath"
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	"testing"
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	"github.com/cilium/tetragon/pkg/defaults"
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	"github.com/stretchr/testify/assert"
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	"golang.org/x/sys/unix"
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)
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var testBtfFiles = []struct {
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	btf     string
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	create  string
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	wantbtf string
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	err     error
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}{
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	{"", "", defaults.DefaultBTFFile, nil},
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	{defaults.DefaultBTFFile, "", defaults.DefaultBTFFile, nil},
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	{"invalid-btf-file", "", "", fmt.Errorf("BTF file 'invalid-btf-file' does not exist should fail")},
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	{"valid-btf-file", "valid-btf-file", "valid-btf-file", nil},
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}
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func setupfiles() func(*testing.T, string, ...string) {
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	return func(t *testing.T, param string, files ...string) {
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		for _, f := range files {
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			if param == "create" {
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				h, e := os.Create(f)
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				assert.NoError(t, e)
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				h.Close()
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			} else if param == "remove" {
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				os.Remove(f)
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			}
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		}
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	}
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}
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func TestObserverFindBTF(t *testing.T) {
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	tmpdir := t.TempDir()
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	old := os.Getenv("TETRAGON_BTF")
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	defer os.Setenv("TETRAGON_BTF", old)
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	handlefiles := setupfiles()
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	for _, test := range testBtfFiles {
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		if test.create != "" {
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			handlefiles(t, "create", test.create, filepath.Join(tmpdir, test.create))
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			defer handlefiles(t, "remove", test.create, filepath.Join(tmpdir, test.create))
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		}
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		_, err := os.Stat(defaults.DefaultBTFFile)
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		if err != nil && test.wantbtf == defaults.DefaultBTFFile {
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			continue
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		}
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		btf, err := observerFindBTF(tmpdir, test.btf)
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		if test.err != nil {
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			assert.Errorf(t, err, "observerFindBTF() on '%s'  -  want:%v  -  got:no error", test.btf, test.err)
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			continue
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		}
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		assert.NoErrorf(t, err, "observerFindBTF() on '%s'  - want:no error  -  got:%v", test.btf, err)
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		assert.Equalf(t, test.wantbtf, btf, "observerFindBTF() on '%s'  -  want:'%s'  -  got:'%s'", test.btf, test.wantbtf, btf)
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		// Test now without lib set
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		btf, err = observerFindBTF("", test.btf)
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		if test.err != nil {
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			assert.Errorf(t, err, "observerFindBTF() on '%s'  -  want:%v  -  got:no error", test.btf, test.err)
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			continue
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		}
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		assert.NoErrorf(t, err, "observerFindBTF() on '%s'  -   want:no error  -  got:%v", test.btf, err)
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		assert.Equalf(t, test.wantbtf, btf, "observerFindBTF() on '%s'  -  want:'%s'  -  got:'%s'", test.btf, test.wantbtf, btf)
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	}
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}
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func TestObserverFindBTFEnv(t *testing.T) {
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	old := os.Getenv("TETRAGON_BTF")
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	defer os.Setenv("TETRAGON_BTF", old)
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	lib := defaults.DefaultTetragonLib
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	btffile := defaults.DefaultBTFFile
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	_, err := os.Stat(btffile)
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	if err != nil {
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		/* No default vmlinux file */
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		btf, err := observerFindBTF("", "")
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		if old != "" {
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			assert.NoError(t, err)
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			assert.NotEmpty(t, btf)
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		} else {
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			assert.Error(t, err)
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			assert.Empty(t, btf)
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		}
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		/* Let's clear up environment vars */
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		os.Setenv("TETRAGON_BTF", "")
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		btf, err = observerFindBTF("", "")
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		assert.Error(t, err)
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		assert.Empty(t, btf)
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		/* Let's try provided path to lib but tests put the btf inside /boot/ */
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		btf, err = observerFindBTF(lib, "")
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		assert.Error(t, err)
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		assert.Empty(t, btf)
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		/* Let's try out the btf file that is inside /boot/ */
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		var uname unix.Utsname
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		err = unix.Uname(&uname)
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		assert.NoError(t, err)
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		kernelVersion := unix.ByteSliceToString(uname.Release[:])
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		os.Setenv("TETRAGON_BTF", filepath.Join("/boot/", fmt.Sprintf("btf-%s", kernelVersion)))
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		btf, err = observerFindBTF(lib, "")
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		assert.NoError(t, err)
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		assert.NotEmpty(t, btf)
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		btffile = btf
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		err = os.Setenv("TETRAGON_BTF", btffile)
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		assert.NoError(t, err)
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		btf, err = observerFindBTF(lib, "")
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		assert.NoError(t, err)
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		assert.Equal(t, btffile, btf)
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	} else {
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		btf, err := observerFindBTF("", "")
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		assert.NoError(t, err)
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		assert.Equal(t, btffile, btf)
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		err = os.Setenv("TETRAGON_BTF", btffile)
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		assert.NoError(t, err)
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		btf, err = observerFindBTF(lib, "")
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		assert.NoError(t, err)
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		assert.Equal(t, btffile, btf)
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	}
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	/* Following should fail */
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	err = os.Setenv("TETRAGON_BTF", "invalid-btf-file")
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	assert.NoError(t, err)
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	btf, err := observerFindBTF(lib, "")
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	assert.Error(t, err)
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	assert.Equal(t, "", btf)
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}
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func TestInitCachedBTF(t *testing.T) {
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	_, err := os.Stat(defaults.DefaultBTFFile)
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	if err != nil {
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		btffile := os.Getenv("TETRAGON_BTF")
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		err = InitCachedBTF(defaults.DefaultTetragonLib, "")
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		if btffile != "" {
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			assert.NoError(t, err)
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			file := GetCachedBTFFile()
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			assert.EqualValues(t, btffile, file, "GetCachedBTFFile()  -  want:'%s'  - got:'%s'", btffile, file)
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		} else {
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			assert.Error(t, err)
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		}
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	} else {
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		err = InitCachedBTF(defaults.DefaultTetragonLib, "")
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		assert.NoError(t, err)
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		btffile := GetCachedBTFFile()
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		assert.EqualValues(t, defaults.DefaultBTFFile, btffile, "GetCachedBTFFile()  -  want:'%s'  - got:'%s'", defaults.DefaultBTFFile, btffile)
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	}
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}
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