net: use bytealg.IndexByte in cgoLookupAddrPTR

Change-Id: I76f4dc1e8bda98936c1198cb45ce8141ca88845b
Reviewed-on: https://go-review.googlesource.com/c/go/+/566235
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

diff --git a/src/net/cgo_unix.go b/src/net/cgo_unix.go
index 82ec4441fcbbc9ffd7f1897bba7ceaaa8b3bf22e..0f62fdeb11307e590e5de6f6aa226f251b91cee7 100644 (file)
--- a/src/net/cgo_unix.go
+++ b/src/net/cgo_unix.go
@@ -14,6 +14,7 @@ package net
 import (
        "context"
        "errors"
+       "internal/bytealg"
        "net/netip"
        "syscall"
        "unsafe"
@@ -287,11 +288,8 @@ func cgoLookupAddrPTR(addr string, sa *_C_struct_sockaddr, salen _C_socklen_t) (
                }
                return nil, &DNSError{Err: err.Error(), Name: addr, IsTemporary: isTemporary, IsNotFound: isErrorNoSuchHost}
        }
-       for i := 0; i < len(b); i++ {
-               if b[i] == 0 {
-                       b = b[:i]
-                       break
-               }
+       if i := bytealg.IndexByte(b, 0); i != -1 {
+               b = b[:i]
        }
        return []string{absDomainName(string(b))}, nil
 }