| // 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 || freebsd || linux || (netbsd && go1.25) |
| |
| package ld |
| |
| import ( |
| "errors" |
| "os" |
| "path/filepath" |
| "runtime" |
| "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 errors.Is(err, errors.ErrUnsupported) || err == errNoFallocate { // 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) |
| } |
| if runtime.GOOS == "darwin" { |
| // Check the number of allocated blocks on Darwin. On Linux (and |
| // perhaps BSDs), stat's Blocks field may not be portable as it |
| // is an implementation detail of the file system. On Darwin, it |
| // is documented as "the actual number of blocks allocated for |
| // the file in 512-byte units". |
| // The check is introduced when fixing a Darwin-specific bug. On |
| // Darwin, the file allocation syscall is a bit tricky. On Linux |
| // and BSDs, it is more straightforward and unlikely to go wrong. |
| // Given these two reasons, only check it on Darwin. |
| // |
| // 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() |
| } |
| } |
