feat: getter of kernel and NFS mount config

Signed-off-by: Raphanus Lo <[email protected]>

nfs/nfs.go

@@ -0,0 +1,97 @@
+package nfs
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"github.com/pkg/errors"
+
+	"github.com/longhorn/go-common-libs/types"
+)
+
+const (
+	nfsmountGlobalSection  = "NFSMount_Global_Options"
+	nfsmountDefaultVersion = "Defaultvers"
+)
+
+// GetSystemDefaultNFSVersion reads the system default NFS version. This config can be overridden by nfsmount.conf under
+// configDir. If configDir is empty, it will be /etc by default. If the nfsmount.conf is absent, or the default
+// version is not overridden in the configuration file, a wrapped ErrNotConfigured error will be returned. It is possible
+// for the caller to tell if the configuration is overridden by errors.Is(err, types.ErrNotConfigured).
+func GetSystemDefaultNFSVersion(configDir string) (major, minor int, err error) {
+	if configDir == "" {
+		configDir = types.SysEtcDirectory
+	}
+
+	configMap, err := getSystemNFSMountConfigMap(configDir)
+	if os.IsNotExist(err) {
+		return 0, 0, fmt.Errorf("system default NFS version is not overridden under %q: %w", configDir, types.ErrNotConfigured)
+	} else if err != nil {
+		return 0, 0, err
+	}
+	if globalSection, ok := configMap[nfsmountGlobalSection]; ok {
+		if configured, ok := globalSection[nfsmountDefaultVersion]; ok {
+			majorStr, minorStr, _ := strings.Cut(configured, ".")
+			major, err := strconv.Atoi(majorStr)
+			if err != nil {
+				return 0, 0, errors.Wrapf(err, "invalid NFS major version %q", configured)
+			}
+
+			minor := 0
+			if minorStr != "" {
+				minor, err = strconv.Atoi(minorStr)
+				if err != nil {
+					return 0, 0, errors.Wrapf(err, "invalid NFS minor version %q", configured)
+				}
+			}
+			return major, minor, nil
+		}
+	}
+	return 0, 0, fmt.Errorf("system default NFS version is not overridden under %q: %w", configDir, types.ErrNotConfigured)
+}
+
+// getSystemNFSMountConfigMap reads the nfsmount.conf under configDir. The returned result is in
+// map[section]map[key]value structure, and the global options is result["NFSMount_Global_Options"]. Refer to man page
+// for more detail: man 5 nfsmount.conf
+func getSystemNFSMountConfigMap(configDir string) (map[string]map[string]string, error) {
+	configFilePath := filepath.Join(configDir, types.NFSMountFileName)
+	configFile, err := os.Open(configFilePath)
+	if err != nil {
+		return nil, err
+	}
+	defer configFile.Close()
+
+	configMap := make(map[string]map[string]string)
+	scanner := bufio.NewScanner(configFile)
+	var section = ""
+	var sectionMap map[string]string
+
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		if strings.HasPrefix(line, "[") {
+			section = strings.TrimSpace(strings.Trim(line, "[]"))
+			continue
+		}
+		if sectionMap = configMap[section]; sectionMap == nil {
+			sectionMap = make(map[string]string)
+			configMap[section] = sectionMap
+		}
+		if key, val, isParsable := strings.Cut(line, "="); isParsable {
+			sectionMap[strings.TrimSpace(key)] = strings.TrimSpace(val)
+		} else {
+			return nil, fmt.Errorf("invalid key-value pair: '%s'", line)
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+	return configMap, nil
+}

nfs/nfs_test.go

@@ -0,0 +1,124 @@
+package nfs
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	. "gopkg.in/check.v1"
+
+	"github.com/longhorn/go-common-libs/types"
+
+	"github.com/longhorn/go-common-libs/test"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type TestSuite struct{}
+
+var _ = Suite(&TestSuite{})
+
+func (s *TestSuite) TestGetSystemDefaultNFSVersion(c *C) {
+	genNFSMountConf := func(dir string, nfsVer string) {
+		data := fmt.Sprintf("[ NFSMount_Global_Options ]\nDefaultvers=%s\n", nfsVer)
+		err := os.WriteFile(filepath.Join(dir, types.NFSMountFileName), []byte(data), 0644)
+		c.Assert(err, IsNil)
+	}
+
+	type testCase struct {
+		setup           func(dir string)
+		expectedMajor   int
+		expectedMinor   int
+		expectedMissing bool
+		expectedError   bool
+	}
+	testCases := map[string]testCase{
+		"GetSystemDefaultNFSVersion(...): system NFS mount config absent": {
+			setup: func(dir string) {
+				_, err := os.Stat(filepath.Join(dir, types.NFSMountFileName))
+				c.Assert(os.IsNotExist(err), Equals, true)
+			},
+			expectedMajor:   0,
+			expectedMinor:   0,
+			expectedMissing: true,
+			expectedError:   true,
+		},
+		"GetSystemDefaultNFSVersion(...): system NFS mount config exist without default ver": {
+			setup: func(dir string) {
+				data := "[ NFSMount_Global_Options ]\notherkey=val\n"
+				err := os.WriteFile(filepath.Join(dir, types.NFSMountFileName), []byte(data), 0644)
+				c.Assert(err, IsNil)
+			},
+			expectedMajor:   0,
+			expectedMinor:   0,
+			expectedMissing: true,
+			expectedError:   true,
+		},
+		"GetSystemDefaultNFSVersion(...): system NFS mount config set default ver to 3": {
+			setup:           func(dir string) { genNFSMountConf(dir, "3") },
+			expectedMajor:   3,
+			expectedMinor:   0,
+			expectedMissing: false,
+			expectedError:   false,
+		},
+		"GetSystemDefaultNFSVersion(...): system NFS mount config set default ver to 4": {
+			setup:           func(dir string) { genNFSMountConf(dir, "4") },
+			expectedMajor:   4,
+			expectedMinor:   0,
+			expectedMissing: false,
+			expectedError:   false,
+		},
+		"GetSystemDefaultNFSVersion(...): system NFS mount config set default ver to 4.0": {
+			setup:           func(dir string) { genNFSMountConf(dir, "4.0") },
+			expectedMajor:   4,
+			expectedMinor:   0,
+			expectedMissing: false,
+			expectedError:   false,
+		},
+		"GetSystemDefaultNFSVersion(...): system NFS mount config set default ver to 4.2": {
+			setup:           func(dir string) { genNFSMountConf(dir, "4.2") },
+			expectedMajor:   4,
+			expectedMinor:   2,
+			expectedMissing: false,
+			expectedError:   false,
+		},
+		"GetSystemDefaultNFSVersion(...): system NFS mount config default ver to invalid value": {
+			setup:           func(dir string) { genNFSMountConf(dir, "???") },
+			expectedMajor:   0,
+			expectedMinor:   0,
+			expectedMissing: false,
+			expectedError:   true,
+		},
+		"GetSystemDefaultNFSVersion(...): system NFS mount config default ver to empty value": {
+			setup:           func(dir string) { genNFSMountConf(dir, "") },
+			expectedMajor:   0,
+			expectedMinor:   0,
+			expectedMissing: false,
+			expectedError:   true,
+		},
+	}
+
+	configDir := c.MkDir()
+
+	for testName, testCase := range testCases {
+		func() {
+			c.Logf("testing utils.%v", testName)
+
+			defer os.Remove(filepath.Join(configDir, types.NFSMountFileName))
+			testCase.setup(configDir)
+
+			major, minor, err := GetSystemDefaultNFSVersion(configDir)
+			c.Assert(major, Equals, testCase.expectedMajor, Commentf(test.ErrResultFmt, testName))
+			c.Assert(minor, Equals, testCase.expectedMinor, Commentf(test.ErrResultFmt, testName))
+			if testCase.expectedMissing {
+				c.Assert(errors.Is(err, types.ErrNotConfigured), Equals, true, Commentf(test.ErrResultFmt, testName))
+			} else if testCase.expectedError {
+				c.Assert(err, NotNil, Commentf(test.ErrErrorFmt, testName))
+			} else {
+				c.Assert(err, IsNil, Commentf(test.ErrErrorFmt, testName))
+			}
+		}()
+	}
+}

sys/sys.go

@@ -1,7 +1,10 @@
 package sys
 
 import (
+	"bufio"
+	"compress/gzip"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -12,6 +15,8 @@ import (
 	"golang.org/x/sys/unix"
 
 	"github.com/longhorn/go-common-libs/types"
+
+	commonio "github.com/longhorn/go-common-libs/io"
 )
 
 // GetKernelRelease returns the kernel release string.
@@ -127,3 +132,74 @@ func getSystemBlockDeviceInfo(sysClassBlockDirectory string, readDirFn func(stri
 	}
 	return deviceInfo, nil
 }
+
+// GetBootKernelConfigMap reads the kernel config into a key-value map. It tries to read kernel config from
+// ${bootDir}/config-${kernelVersion}, and comments are ignored. If the bootDir is empty, it points to /boot by default.
+func GetBootKernelConfigMap(bootDir, kernelVersion string) (configMap map[string]string, err error) {
+	if kernelVersion == "" {
+		return nil, fmt.Errorf("kernelVersion cannot be empty")
+	}
+	if bootDir == "" {
+		bootDir = types.SysBootDirectory
+	}
+
+	defer func() {
+		err = errors.Wrapf(err, "failed to get kernel config map from %s", bootDir)
+	}()
+
+	configPath := filepath.Join(bootDir, "config-"+kernelVersion)
+	configContent, err := commonio.ReadFileContent(configPath)
+	if err != nil {
+		return nil, err
+	}
+	return parseKernelModuleConfigMap(strings.NewReader(configContent))
+}
+
+// GetProcKernelConfigMap reads the kernel config into a key-value map. It tries to read kernel config from
+// procfs mounted at procDir from the view of processName in namespace. If the procDir is empty, it points to /proc by
+// default.
+func GetProcKernelConfigMap(procDir string) (configMap map[string]string, err error) {
+	if procDir == "" {
+		procDir = types.SysProcDirectory
+	}
+
+	defer func() {
+		err = errors.Wrapf(err, "failed to get kernel config map from %s", procDir)
+	}()
+
+	configPath := filepath.Join(procDir, types.SysKernelConfigGz)
+	configFile, err := os.Open(configPath)
+	if err != nil {
+		return nil, err
+	}
+	defer configFile.Close()
+	gzReader, err := gzip.NewReader(configFile)
+	if err != nil {
+		return nil, err
+	}
+	defer gzReader.Close()
+	return parseKernelModuleConfigMap(gzReader)
+}
+
+// parseKernelModuleConfigMap parses the kernel config into key-value map. All commented items will be ignored.
+func parseKernelModuleConfigMap(contentReader io.Reader) (map[string]string, error) {
+	configMap := map[string]string{}
+
+	scanner := bufio.NewScanner(contentReader)
+	for scanner.Scan() {
+		config := scanner.Text()
+		if !strings.HasPrefix(config, "CONFIG_") {
+			continue
+		}
+		key, val, parsable := strings.Cut(config, "=")
+		if !parsable {
+			return nil, fmt.Errorf("failed to parse kernel config %s", config)
+		}
+		configMap[strings.TrimSpace(key)] = strings.TrimSpace(val)
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+	return configMap, nil
+}