sandbox: resolve inverted flags in op

Signed-off-by: Ophestra <cat@gensokyo.uk>

sandbox/mount.go

@@ -1,82 +1,22 @@
 package sandbox
 
 import (
-	"errors"
 	"fmt"
 	"os"
-	"strings"
 	"syscall"
 )
 
-const (
-	BindOptional = 1 << iota
-	BindSource
-	BindWritable
-	BindDevice
-
-	bindResolved
-	bindAbsolute
-	bindRecursive
-)
-
-func bindMount(src, dest string, flags int) error {
-	target := toSysroot(dest)
-	var source string
-
-	if flags&BindSource != 0 {
-		if flags&BindOptional != 0 {
-			return msg.WrapErr(syscall.EINVAL,
-				"flag source excludes optional")
-		}
-	} else if flags&bindResolved == 0 {
-		return msg.WrapErr(syscall.EBADE,
-			"flag source must be set on direct bind call")
-	}
-
-	if flags&bindAbsolute != 0 {
-		if flags&BindSource == 0 {
-			return msg.WrapErr(syscall.EINVAL,
-				"flag absolute implies source")
-		}
-		source = src
-	} else {
-		source = toHost(src)
-	}
-
-	if fi, err := os.Stat(source); err != nil {
-		return msg.WrapErr(err, err.Error())
-	} else if fi.IsDir() {
-		if err = os.MkdirAll(target, 0755); err != nil {
-			return msg.WrapErr(err, err.Error())
-		}
-	} else if err = ensureFile(target, 0444); err != nil {
-		if errors.Is(err, syscall.EISDIR) {
-			return msg.WrapErr(err,
-				fmt.Sprintf("path %q is a directory", dest))
-		}
-		return wrapErrSuffix(err,
-			fmt.Sprintf("cannot create %q:", dest))
-	}
-
+func (p *procPaths) bindMount(source, target string, flags uintptr, eq bool) error {
 	var mf uintptr = syscall.MS_SILENT | syscall.MS_BIND
-	if flags&bindRecursive != 0 {
-		mf |= syscall.MS_REC
-	}
-	if flags&BindWritable == 0 {
-		mf |= syscall.MS_RDONLY
-	}
-	if flags&BindDevice == 0 {
-		mf |= syscall.MS_NODEV
-	}
-	if msg.IsVerbose() {
-		if strings.TrimPrefix(source, hostPath) == strings.TrimPrefix(target, sysrootPath) {
-			msg.Verbosef("resolved %q flags %#x", target, mf)
-		} else {
-			msg.Verbosef("resolved %q on %q flags %#x", source, target, mf)
-		}
+	mf |= flags & syscall.MS_REC
+	if eq {
+		msg.Verbosef("resolved %q flags %#x", target, mf)
+	} else {
+		msg.Verbosef("resolved %q on %q flags %#x", source, target, mf)
 	}
+
 	return wrapErrSuffix(syscall.Mount(source, target, "", mf, ""),
-		fmt.Sprintf("cannot bind %q on %q:", src, dest))
+		fmt.Sprintf("cannot mount %q on %q:", source, target))
 }
 
 func mountTmpfs(fsname, name string, size int, perm os.FileMode) error {