feat: add tests for proc gz config

Signed-off-by: grantseltzer <grantseltzer@gmail.com>

libbpfgo/helpers/kernel_features.go

@@ -21,12 +21,20 @@ type KernelConfig map[string]string
 // /boot/config.gz
 func InitKernelConfig(k KernelConfig) (KernelConfig, error) {
 
-	err := k.getBootConfig()
+	x := unix.Utsname{}
+	err := unix.Uname(&x)
+	if err != nil {
+		return nil, fmt.Errorf("could not determine uname release: %v", err)
+	}
+
+	bootConfigPath := fmt.Sprintf("/boot/config-%s", bytes.Trim(x.Release[:], "\x00"))
+
+	err = k.getBootConfig(bootConfigPath)
 	if err == nil {
 		return k, nil
 	}
 
-	err2 := k.getProcGZConfig()
+	err2 := k.getProcGZConfig("/proc/config.gz")
 	if err != nil {
 		return nil, fmt.Errorf("%v %v", err, err2)
 	}
@@ -44,15 +52,7 @@ func (k KernelConfig) GetKernelConfigValue(key string) (string, error) {
 	return v, nil
 }
 
-func (k KernelConfig) getBootConfig() error {
-
-	x := unix.Utsname{}
-	err := unix.Uname(&x)
-	if err != nil {
-		return fmt.Errorf("could not determine uname release: %v", err)
-	}
-
-	bootConfigPath := fmt.Sprintf("/boot/config-%s", bytes.Trim(x.Release[:], "\x00"))
+func (k KernelConfig) getBootConfig(bootConfigPath string) error {
 
 	configFile, err := os.Open(bootConfigPath)
 	if err != nil {
@@ -66,9 +66,7 @@ func (k KernelConfig) getBootConfig() error {
 	return nil
 }
 
-func (k KernelConfig) getProcGZConfig() error {
-
-	procConfigPath := "/proc/config.gz"
+func (k KernelConfig) getProcGZConfig(procConfigPath string) error {
 
 	configFile, err := os.Open(procConfigPath)
 	if err != nil {

libbpfgo/helpers/kernel_features_test.go

@@ -0,0 +1,52 @@
+package helpers
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetProcGZConfig(t *testing.T) {
+	testCases := []struct {
+		name           string
+		goldenFilePath string
+		expectedMap    KernelConfig
+		expectedError  error
+	}{
+		{
+			name:           "non-existant",
+			goldenFilePath: "foobarblahblahblah",
+			expectedMap:    KernelConfig{},
+			expectedError:  errors.New("could not open foobarblahblahblah: open foobarblahblahblah: no such file or directory"),
+		},
+		{
+			name:           "invalid zip format",
+			goldenFilePath: "testdata/tarred_config.tar",
+			expectedMap:    KernelConfig{},
+			expectedError:  errors.New("gzip: invalid header"),
+		},
+		{
+			name:           "standard config",
+			goldenFilePath: "testdata/config_standard.gz",
+			expectedMap:    KernelConfig{"CONFIG_ARCH_WANT_DEFAULT_BPF_JIT": "y", "CONFIG_BPF": "y", "CONFIG_BPF_JIT_ALWAYS_ON": "y", "CONFIG_BPF_JIT_DEFAULT_ON": "y", "CONFIG_BPF_LSM": "y", "CONFIG_BPF_PRELOAD": "y", "CONFIG_BPF_PRELOAD_UMD": "m", "CONFIG_BPF_SYSCALL": "y", "CONFIG_IPV6_SEG6_BPF": "y", "CONFIG_NETFILTER_XT_MATCH_BPF": "m"},
+			expectedError:  nil,
+		},
+		{
+			name:           "config with comments in it",
+			goldenFilePath: "testdata/comments_config.gz",
+			expectedMap:    KernelConfig{"CONFIG_BPF": "y", "CONFIG_BPF_PRELOAD_UMD": "m", "CONFIG_BPF_SYSCALL": "y"},
+			expectedError:  nil,
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.name, func(t *testing.T) {
+
+			var kconfig KernelConfig = make(map[string]string)
+			err := kconfig.getProcGZConfig(tt.goldenFilePath)
+			assert.Equal(t, tt.expectedError, err)
+			assert.Equal(t, tt.expectedMap, kconfig)
+		})
+	}
+}