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// 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.
//go:build darwin || linux
// +build darwin linux
package ld
import (
"os"
"path/filepath"
"syscall"
"testing"
)
func TestFallocate(t *testing.T) {
dir := t.TempDir()
filename := filepath.Join(dir, "a.out")
out := NewOutBuf(nil)
err := out.Open(filename)
if err != nil {
t.Fatalf("Open file failed: %v", err)
}
defer out.Close()
// Try fallocate first.
for {
err = out.fallocate(1 << 10)
if err == syscall.EOPNOTSUPP { // The underlying file system may not support fallocate
t.Skip("fallocate is not supported")
}
if err == syscall.EINTR {
continue // try again
}
if err != nil {
t.Fatalf("fallocate failed: %v", err)
}
break
}
// Mmap 1 MiB initially, and grow to 2 and 3 MiB.
// Check if the file size and disk usage is expected.
for _, sz := range []int64{1 << 20, 2 << 20, 3 << 20} {
err = out.Mmap(uint64(sz))
if err != nil {
t.Fatalf("Mmap failed: %v", err)
}
stat, err := os.Stat(filename)
if err != nil {
t.Fatalf("Stat failed: %v", err)
}
if got := stat.Size(); got != sz {
t.Errorf("unexpected file size: got %d, want %d", got, sz)
}
// The number of blocks must be enough for the requested size.
// We used to require an exact match, but it appears that
// some file systems allocate a few extra blocks in some cases.
// See issue #41127.
if got, want := stat.Sys().(*syscall.Stat_t).Blocks, (sz+511)/512; got < want {
t.Errorf("unexpected disk usage: got %d blocks, want at least %d", got, want)
}
out.munmap()
}
}
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