fix ioutil deprecation warnings

Seen in github.com//pull/164.

Signed-off-by: Valentin Rothberg <[email protected]>

internal/host/host_nocgo.go

@@ -1,3 +1,4 @@
+//go:build !cgo
 // +build !cgo
 
 // Copyright 2018 psgo authors
@@ -21,7 +22,7 @@ package host
 import (
 	"encoding/binary"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"unsafe"
 )
 
@@ -46,7 +47,7 @@ const (
 
 func getFromAuxv(what uint, whatName string) (uint, error) {
 	dataLen := int(unsafe.Sizeof(int(0)))
-	p, err := ioutil.ReadFile("/proc/self/auxv")
+	p, err := os.ReadFile("/proc/self/auxv")
 	if err != nil {
 		return 0, err
 	}

internal/proc/attr.go

@@ -17,7 +17,6 @@ package proc
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strings"
 
@@ -27,7 +26,7 @@ import (
 // ParseAttrCurrent returns the contents of /proc/$pid/attr/current of "?" if
 // labeling is not supported on the host.
 func ParseAttrCurrent(pid string) (string, error) {
-	data, err := ioutil.ReadFile(fmt.Sprintf("/proc/%s/attr/current", pid))
+	data, err := os.ReadFile(fmt.Sprintf("/proc/%s/attr/current", pid))
 	if err != nil {
 		_, err = os.Stat(fmt.Sprintf("/proc/%s", pid))
 		if errors.Is(err, os.ErrNotExist) || errors.Is(err, unix.ESRCH) {

internal/proc/cmdline.go

@@ -17,12 +17,12 @@ package proc
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"os"
 )
 
 // ParseCmdLine parses a /proc/$pid/cmdline file and returns a string slice.
 func ParseCmdLine(pid string) ([]string, error) {
-	data, err := ioutil.ReadFile(fmt.Sprintf("/proc/%s/cmdline", pid))
+	data, err := os.ReadFile(fmt.Sprintf("/proc/%s/cmdline", pid))
 	if err != nil {
 		return nil, err
 	}

internal/proc/stat.go

@@ -17,7 +17,7 @@ package proc
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"strings"
 )
 
@@ -114,7 +114,7 @@ type Stat struct {
 
 // readStat is used for mocking in unit tests.
 var readStat = func(path string) (string, error) {
-	rawData, err := ioutil.ReadFile(path)
+	rawData, err := os.ReadFile(path)
 	if err != nil {
 		return "", err
 	}

psgo.go

@@ -29,7 +29,6 @@ package psgo
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"runtime"
 	"sort"
@@ -110,7 +109,7 @@ func findID(idStr string, mapping []idtools.IDMap, lookupFunc func(uid string) (
 	}
 
 	// User not found, read the overflow
-	overflow, err := ioutil.ReadFile(overflowFile)
+	overflow, err := os.ReadFile(overflowFile)
 	if err != nil {
 		return "", err
 	}