chore: vendor

vendor/golang.org/x/sys/unix/cap_freebsd.go

@@ -0,0 +1,195 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build freebsd
+
+package unix
+
+import (
+	"errors"
+	"fmt"
+)
+
+// Go implementation of C mostly found in /usr/src/sys/kern/subr_capability.c
+
+const (
+	// This is the version of CapRights this package understands. See C implementation for parallels.
+	capRightsGoVersion = CAP_RIGHTS_VERSION_00
+	capArSizeMin       = CAP_RIGHTS_VERSION_00 + 2
+	capArSizeMax       = capRightsGoVersion + 2
+)
+
+var (
+	bit2idx = []int{
+		-1, 0, 1, -1, 2, -1, -1, -1, 3, -1, -1, -1, -1, -1, -1, -1,
+		4, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	}
+)
+
+func capidxbit(right uint64) int {
+	return int((right >> 57) & 0x1f)
+}
+
+func rightToIndex(right uint64) (int, error) {
+	idx := capidxbit(right)
+	if idx < 0 || idx >= len(bit2idx) {
+		return -2, fmt.Errorf("index for right 0x%x out of range", right)
+	}
+	return bit2idx[idx], nil
+}
+
+func caprver(right uint64) int {
+	return int(right >> 62)
+}
+
+func capver(rights *CapRights) int {
+	return caprver(rights.Rights[0])
+}
+
+func caparsize(rights *CapRights) int {
+	return capver(rights) + 2
+}
+
+// CapRightsSet sets the permissions in setrights in rights.
+func CapRightsSet(rights *CapRights, setrights []uint64) error {
+	// This is essentially a copy of cap_rights_vset()
+	if capver(rights) != CAP_RIGHTS_VERSION_00 {
+		return fmt.Errorf("bad rights version %d", capver(rights))
+	}
+
+	n := caparsize(rights)
+	if n < capArSizeMin || n > capArSizeMax {
+		return errors.New("bad rights size")
+	}
+
+	for _, right := range setrights {
+		if caprver(right) != CAP_RIGHTS_VERSION_00 {
+			return errors.New("bad right version")
+		}
+		i, err := rightToIndex(right)
+		if err != nil {
+			return err
+		}
+		if i >= n {
+			return errors.New("index overflow")
+		}
+		if capidxbit(rights.Rights[i]) != capidxbit(right) {
+			return errors.New("index mismatch")
+		}
+		rights.Rights[i] |= right
+		if capidxbit(rights.Rights[i]) != capidxbit(right) {
+			return errors.New("index mismatch (after assign)")
+		}
+	}
+
+	return nil
+}
+
+// CapRightsClear clears the permissions in clearrights from rights.
+func CapRightsClear(rights *CapRights, clearrights []uint64) error {
+	// This is essentially a copy of cap_rights_vclear()
+	if capver(rights) != CAP_RIGHTS_VERSION_00 {
+		return fmt.Errorf("bad rights version %d", capver(rights))
+	}
+
+	n := caparsize(rights)
+	if n < capArSizeMin || n > capArSizeMax {
+		return errors.New("bad rights size")
+	}
+
+	for _, right := range clearrights {
+		if caprver(right) != CAP_RIGHTS_VERSION_00 {
+			return errors.New("bad right version")
+		}
+		i, err := rightToIndex(right)
+		if err != nil {
+			return err
+		}
+		if i >= n {
+			return errors.New("index overflow")
+		}
+		if capidxbit(rights.Rights[i]) != capidxbit(right) {
+			return errors.New("index mismatch")
+		}
+		rights.Rights[i] &= ^(right & 0x01FFFFFFFFFFFFFF)
+		if capidxbit(rights.Rights[i]) != capidxbit(right) {
+			return errors.New("index mismatch (after assign)")
+		}
+	}
+
+	return nil
+}
+
+// CapRightsIsSet checks whether all the permissions in setrights are present in rights.
+func CapRightsIsSet(rights *CapRights, setrights []uint64) (bool, error) {
+	// This is essentially a copy of cap_rights_is_vset()
+	if capver(rights) != CAP_RIGHTS_VERSION_00 {
+		return false, fmt.Errorf("bad rights version %d", capver(rights))
+	}
+
+	n := caparsize(rights)
+	if n < capArSizeMin || n > capArSizeMax {
+		return false, errors.New("bad rights size")
+	}
+
+	for _, right := range setrights {
+		if caprver(right) != CAP_RIGHTS_VERSION_00 {
+			return false, errors.New("bad right version")
+		}
+		i, err := rightToIndex(right)
+		if err != nil {
+			return false, err
+		}
+		if i >= n {
+			return false, errors.New("index overflow")
+		}
+		if capidxbit(rights.Rights[i]) != capidxbit(right) {
+			return false, errors.New("index mismatch")
+		}
+		if (rights.Rights[i] & right) != right {
+			return false, nil
+		}
+	}
+
+	return true, nil
+}
+
+func capright(idx uint64, bit uint64) uint64 {
+	return ((1 << (57 + idx)) | bit)
+}
+
+// CapRightsInit returns a pointer to an initialised CapRights structure filled with rights.
+// See man cap_rights_init(3) and rights(4).
+func CapRightsInit(rights []uint64) (*CapRights, error) {
+	var r CapRights
+	r.Rights[0] = (capRightsGoVersion << 62) | capright(0, 0)
+	r.Rights[1] = capright(1, 0)
+
+	err := CapRightsSet(&r, rights)
+	if err != nil {
+		return nil, err
+	}
+	return &r, nil
+}
+
+// CapRightsLimit reduces the operations permitted on fd to at most those contained in rights.
+// The capability rights on fd can never be increased by CapRightsLimit.
+// See man cap_rights_limit(2) and rights(4).
+func CapRightsLimit(fd uintptr, rights *CapRights) error {
+	return capRightsLimit(int(fd), rights)
+}
+
+// CapRightsGet returns a CapRights structure containing the operations permitted on fd.
+// See man cap_rights_get(3) and rights(4).
+func CapRightsGet(fd uintptr) (*CapRights, error) {
+	r, err := CapRightsInit(nil)
+	if err != nil {
+		return nil, err
+	}
+	err = capRightsGet(capRightsGoVersion, int(fd), r)
+	if err != nil {
+		return nil, err
+	}
+	return r, nil
+}