all: update to use os.ReadFile, os.WriteFile, os.CreateTemp, os.MkdirTemp

As part of #42026, these helpers from io/ioutil were moved to os.
(ioutil.TempFile and TempDir became os.CreateTemp and MkdirTemp.)

Update the Go tree to use the preferred names.

As usual, code compiled with the Go 1.4 bootstrap toolchain
and code vendored from other sources is excluded.

ReadDir changes are in a separate CL, because they are not a
simple search and replace.

For #42026.

Change-Id: If318df0216d57e95ea0c4093b89f65e5b0ababb3
Reviewed-on: https://go-review.googlesource.com/c/go/+/266365
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

1 files changed, 7 insertions, 8 deletions

diff --git a/src/syscall/exec_linux_test.go b/src/syscall/exec_linux_test.go
index b79dee7525..ac3a5754ae 100644
--- a/src/syscall/exec_linux_test.go
+++ b/src/syscall/exec_linux_test.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"os/user"
@@ -65,7 +64,7 @@ func skipNoUserNamespaces(t *testing.T) {
 func skipUnprivilegedUserClone(t *testing.T) {
 	// Skip the test if the sysctl that prevents unprivileged user
 	// from creating user namespaces is enabled.
-	data, errRead := ioutil.ReadFile("/proc/sys/kernel/unprivileged_userns_clone")
+	data, errRead := os.ReadFile("/proc/sys/kernel/unprivileged_userns_clone")
 	if errRead != nil || len(data) < 1 || data[0] == '0' {
 		t.Skip("kernel prohibits user namespace in unprivileged process")
 	}
@@ -98,7 +97,7 @@ func checkUserNS(t *testing.T) {
 	// On Centos 7 make sure they set the kernel parameter user_namespace=1
 	// See issue 16283 and 20796.
 	if _, err := os.Stat("/sys/module/user_namespace/parameters/enable"); err == nil {
-		buf, _ := ioutil.ReadFile("/sys/module/user_namespace/parameters/enabled")
+		buf, _ := os.ReadFile("/sys/module/user_namespace/parameters/enabled")
 		if !strings.HasPrefix(string(buf), "Y") {
 			t.Skip("kernel doesn't support user namespaces")
 		}
@@ -106,7 +105,7 @@ func checkUserNS(t *testing.T) {
 
 	// On Centos 7.5+, user namespaces are disabled if user.max_user_namespaces = 0
 	if _, err := os.Stat("/proc/sys/user/max_user_namespaces"); err == nil {
-		buf, errRead := ioutil.ReadFile("/proc/sys/user/max_user_namespaces")
+		buf, errRead := os.ReadFile("/proc/sys/user/max_user_namespaces")
 		if errRead == nil && buf[0] == '0' {
 			t.Skip("kernel doesn't support user namespaces")
 		}
@@ -226,7 +225,7 @@ func TestUnshare(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	orig, err := ioutil.ReadFile(path)
+	orig, err := os.ReadFile(path)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -349,7 +348,7 @@ func TestUnshareMountNameSpace(t *testing.T) {
 		t.Skip("kernel prohibits unshare in unprivileged process, unless using user namespace")
 	}
 
-	d, err := ioutil.TempDir("", "unshare")
+	d, err := os.MkdirTemp("", "unshare")
 	if err != nil {
 		t.Fatalf("tempdir: %v", err)
 	}
@@ -391,7 +390,7 @@ func TestUnshareMountNameSpaceChroot(t *testing.T) {
 		t.Skip("kernel prohibits unshare in unprivileged process, unless using user namespace")
 	}
 
-	d, err := ioutil.TempDir("", "unshare")
+	d, err := os.MkdirTemp("", "unshare")
 	if err != nil {
 		t.Fatalf("tempdir: %v", err)
 	}
@@ -599,7 +598,7 @@ func testAmbientCaps(t *testing.T, userns bool) {
 	}
 
 	// Copy the test binary to a temporary location which is readable by nobody.
-	f, err := ioutil.TempFile("", "gotest")
+	f, err := os.CreateTemp("", "gotest")
 	if err != nil {
 		t.Fatal(err)
 	}