| // 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() | |
| } | |
| } | |