// Copyright 2020 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. package ld import ( "syscall" "unsafe" ) func (out *OutBuf) fallocate(size uint64) error { stat, err := out.f.Stat() if err != nil { return err } // F_PEOFPOSMODE allocates from the end of the file, so we want the size difference. // Apparently, it uses the end of the allocation, instead of the logical end of the // the file. cursize := uint64(stat.Sys().(*syscall.Stat_t).Blocks * 512) // allocated size if size <= cursize { return nil } store := &syscall.Fstore_t{ Flags: syscall.F_ALLOCATEALL, Posmode: syscall.F_PEOFPOSMODE, Offset: 0, Length: int64(size - cursize), } _, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(out.f.Fd()), syscall.F_PREALLOCATE, uintptr(unsafe.Pointer(store))) if errno != 0 { return errno } return nil } func (out *OutBuf) purgeSignatureCache() { // Apparently, the Darwin kernel may cache the code signature at mmap. // When we mmap the output buffer, it doesn't have a code signature // (as we haven't generated one). Invalidate the kernel cache now that // we have generated the signature. See issue #42684. syscall.Syscall(syscall.SYS_MSYNC, uintptr(unsafe.Pointer(&out.buf[0])), uintptr(len(out.buf)), syscall.MS_INVALIDATE) // Best effort. Ignore error. }