mirror of https://github.com/golang/go.git
49 lines
1.4 KiB
Go
49 lines
1.4 KiB
Go
// Copyright 2020 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package ld
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import (
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"syscall"
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"unsafe"
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)
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// Implemented in the syscall package.
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//
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//go:linkname fcntl syscall.fcntl
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func fcntl(fd int, cmd int, arg int) (int, error)
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func (out *OutBuf) fallocate(size uint64) error {
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stat, err := out.f.Stat()
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if err != nil {
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return err
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}
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// F_PEOFPOSMODE allocates from the end of the file, so we want the size difference.
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// Apparently, it uses the end of the allocation, instead of the logical end of the
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// file.
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cursize := uint64(stat.Sys().(*syscall.Stat_t).Blocks * 512) // allocated size
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if size <= cursize {
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return nil
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}
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store := &syscall.Fstore_t{
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Flags: syscall.F_ALLOCATEALL,
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Posmode: syscall.F_PEOFPOSMODE,
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Offset: 0,
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Length: int64(size - cursize),
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}
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_, err = fcntl(int(out.f.Fd()), syscall.F_PREALLOCATE, int(uintptr(unsafe.Pointer(store))))
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return err
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}
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func (out *OutBuf) purgeSignatureCache() {
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// Apparently, the Darwin kernel may cache the code signature at mmap.
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// When we mmap the output buffer, it doesn't have a code signature
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// (as we haven't generated one). Invalidate the kernel cache now that
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// we have generated the signature. See issue #42684.
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syscall.Syscall(syscall.SYS_MSYNC, uintptr(unsafe.Pointer(&out.buf[0])), uintptr(len(out.buf)), syscall.MS_INVALIDATE)
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// Best effort. Ignore error.
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}
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