sys: un-export runningPrivileged(), remove runningUnprivileged()

thaJeztah · thaJeztah · commit badd60d3f6e9 · 2021-04-07T19:16:49.000+02:00
These are currently only used inside this package, so we might
as well un-export them until we need them elsewhere.

Also updated SetOOMScore() to first check for privileged; check for privileged
looks to be the "faster" path, and checking it first could (in case of non-
privileged) save having to read and parse /proc/self/uid_map.

Signed-off-by: Sebastiaan van Stijn &lt;github@gone.nl&gt;
diff --git a/sys/env.go b/sys/env.go
diff --git a/sys/mount_linux_test.go b/sys/mount_linux_test.go
@@ -32,7 +32,7 @@ import (
 type fMountatCaseFunc func(t *testing.T, root string)
 
 func TestFMountat(t *testing.T) {
-	if RunningUnprivileged() {
+	if !runningPrivileged() {
 		t.Skip("Needs to be run as root")
 		return
 	}
diff --git a/sys/oom_linux.go b/sys/oom_linux.go
@@ -24,6 +24,7 @@ import (
 	"strings"
 
 	"github.com/containerd/containerd/pkg/userns"
+	"golang.org/x/sys/unix"
 )
 
 const (
@@ -42,7 +43,7 @@ func SetOOMScore(pid, score int) error {
 	}
 	defer f.Close()
 	if _, err = f.WriteString(strconv.Itoa(score)); err != nil {
-		if os.IsPermission(err) && (userns.RunningInUserNS() || RunningUnprivileged()) {
+		if os.IsPermission(err) && (!runningPrivileged() || userns.RunningInUserNS()) {
 			return nil
 		}
 		return err
@@ -59,3 +60,9 @@ func GetOOMScoreAdj(pid int) (int, error) {
 	}
 	return strconv.Atoi(strings.TrimSpace(string(data)))
 }
+
+// runningPrivileged returns true if the effective user ID of the
+// calling process is 0
+func runningPrivileged() bool {
+	return unix.Geteuid() == 0
+}
diff --git a/sys/oom_linux_test.go b/sys/oom_linux_test.go
@@ -37,7 +37,7 @@ func TestSetPositiveOomScoreAdjustment(t *testing.T) {
 }
 
 func TestSetNegativeOomScoreAdjustmentWhenPrivileged(t *testing.T) {
-	if RunningUnprivileged() {
+	if !runningPrivileged() {
 		t.Skip("Needs to be run as root")
 		return
 	}
@@ -51,7 +51,7 @@ func TestSetNegativeOomScoreAdjustmentWhenPrivileged(t *testing.T) {
 }
 
 func TestSetNegativeOomScoreAdjustmentWhenUnprivilegedHasNoEffect(t *testing.T) {
-	if RunningPrivileged() {
+	if runningPrivileged() {
 		t.Skip("Needs to be run as non-root")
 		return
 	}

Original file line number	Diff line number	Diff line change
`@@ -32,7 +32,7 @@ import (`
`32`	`32`	`type fMountatCaseFunc func(t *testing.T, root string)`
`33`	`33`
`34`	`34`	`func TestFMountat(t *testing.T) {`
`35`		`- if RunningUnprivileged() {`
	`35`	`+ if !runningPrivileged() {`
`36`	`36`	`t.Skip("Needs to be run as root")`
`37`	`37`	`return`
`38`	`38`	`}`
Original file line number	Diff line number	Diff line change
`@@ -24,6 +24,7 @@ import (`
`24`	`24`	`"strings"`
`25`	`25`
`26`	`26`	`"github.com/containerd/containerd/pkg/userns"`
	`27`	`+ "golang.org/x/sys/unix"`
`27`	`28`	`)`
`28`	`29`
`29`	`30`	`const (`
`@@ -42,7 +43,7 @@ func SetOOMScore(pid, score int) error {`
`42`	`43`	`}`
`43`	`44`	`defer f.Close()`
`44`	`45`	`if _, err = f.WriteString(strconv.Itoa(score)); err != nil {`
`45`		`- if os.IsPermission(err) && (userns.RunningInUserNS() \|\| RunningUnprivileged()) {`
	`46`	`+ if os.IsPermission(err) && (!runningPrivileged() \|\| userns.RunningInUserNS()) {`
`46`	`47`	`return nil`
`47`	`48`	`}`
`48`	`49`	`return err`
`@@ -59,3 +60,9 @@ func GetOOMScoreAdj(pid int) (int, error) {`
`59`	`60`	`}`
`60`	`61`	`return strconv.Atoi(strings.TrimSpace(string(data)))`
`61`	`62`	`}`
	`63`	`+`
	`64`	`+// runningPrivileged returns true if the effective user ID of the`
	`65`	`+// calling process is 0`
	`66`	`+func runningPrivileged() bool {`
	`67`	`+ return unix.Geteuid() == 0`
	`68`	`+}`
Original file line number	Diff line number	Diff line change
`@@ -37,7 +37,7 @@ func TestSetPositiveOomScoreAdjustment(t *testing.T) {`
`37`	`37`	`}`
`38`	`38`
`39`	`39`	`func TestSetNegativeOomScoreAdjustmentWhenPrivileged(t *testing.T) {`
`40`		`- if RunningUnprivileged() {`
	`40`	`+ if !runningPrivileged() {`
`41`	`41`	`t.Skip("Needs to be run as root")`
`42`	`42`	`return`
`43`	`43`	`}`
`@@ -51,7 +51,7 @@ func TestSetNegativeOomScoreAdjustmentWhenPrivileged(t *testing.T) {`
`51`	`51`	`}`
`52`	`52`
`53`	`53`	`func TestSetNegativeOomScoreAdjustmentWhenUnprivilegedHasNoEffect(t *testing.T) {`
`54`		`- if RunningPrivileged() {`
	`54`	`+ if runningPrivileged() {`
`55`	`55`	`t.Skip("Needs to be run as non-root")`
`56`	`56`	`return`
`57`	`57`	`}`