pkg/osutil: add DiskUsage function

DiskUsage returns total recursive disk usage of the dir (similar to du -s).

7 files changed, 73 insertions, 103 deletions

diff --git a/pkg/osutil/osutil.go b/pkg/osutil/osutil.go
index 936465ee7..fa963a3fb 100644
--- a/pkg/osutil/osutil.go
+++ b/pkg/osutil/osutil.go
@@ -11,6 +11,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/fs"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -366,3 +367,20 @@ func CreationTime(fi os.FileInfo) time.Time {
 //
 //go:linkname MonotonicNano runtime.nanotime
 func MonotonicNano() time.Duration
+
+// DiskUsage returns total recursive disk usage of the dir (similar to du -s).
+func DiskUsage(dir string) (uint64, error) {
+	var total uint64
+	err := filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		info, err := d.Info()
+		if err != nil {
+			return err
+		}
+		total += sysDiskUsage(info)
+		return nil
+	})
+	return total, err
+}
diff --git a/pkg/osutil/osutil_darwin.go b/pkg/osutil/osutil_darwin.go
deleted file mode 100644
index 0b1f30711..000000000
--- a/pkg/osutil/osutil_darwin.go
+++ /dev/null
@@ -1,39 +0,0 @@
-// Copyright 2017 syzkaller project authors. All rights reserved.
-// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
-
-package osutil
-
-import (
-	"os"
-	"os/exec"
-	"time"
-)
-
-func creationTime(fi os.FileInfo) time.Time {
-	return time.Time{}
-}
-
-func RemoveAll(dir string) error {
-	return os.RemoveAll(dir)
-}
-
-func SystemMemorySize() uint64 {
-	return 0
-}
-
-func prolongPipe(r, w *os.File) {
-}
-
-func Sandbox(cmd *exec.Cmd, user, net bool) error {
-	return nil
-}
-
-func SandboxChown(file string) error {
-	return nil
-}
-
-func setPdeathsig(cmd *exec.Cmd, hardKill bool) {
-}
-
-func killPgroup(cmd *exec.Cmd) {
-}
diff --git a/pkg/osutil/osutil_fuchsia.go b/pkg/osutil/osutil_fuchsia.go
index fce4e38ba..a4a8c22b2 100644
--- a/pkg/osutil/osutil_fuchsia.go
+++ b/pkg/osutil/osutil_fuchsia.go
@@ -7,43 +7,12 @@ package osutil
 
 import (
 	"os"
-	"os/exec"
-	"time"
 )
 
-func creationTime(fi os.FileInfo) time.Time {
-	return time.Time{}
-}
-
 func HandleInterrupts(shutdown chan struct{}) {
 }
 
-func RemoveAll(dir string) error {
-	return os.RemoveAll(dir)
-}
-
-func SystemMemorySize() uint64 {
-	return 0
-}
-
 func ProcessExitStatus(ps *os.ProcessState) int {
 	// TODO: can be extracted from ExitStatus string.
 	return 0
 }
-
-func prolongPipe(r, w *os.File) {
-}
-
-func Sandbox(cmd *exec.Cmd, user, net bool) error {
-	return nil
-}
-
-func SandboxChown(file string) error {
-	return nil
-}
-
-func setPdeathsig(cmd *exec.Cmd, hardKill bool) {
-}
-
-func killPgroup(cmd *exec.Cmd) {
-}
diff --git a/pkg/osutil/osutil_linux.go b/pkg/osutil/osutil_linux.go
index 63743a5f2..50be9b047 100644
--- a/pkg/osutil/osutil_linux.go
+++ b/pkg/osutil/osutil_linux.go
@@ -5,6 +5,7 @@ package osutil
 
 import (
 	"fmt"
+	"io/fs"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -150,3 +151,8 @@ func prolongPipe(r, w *os.File) {
 		syscall.Syscall(syscall.SYS_FCNTL, w.Fd(), syscall.F_SETPIPE_SZ, uintptr(sz))
 	}
 }
+
+func sysDiskUsage(info fs.FileInfo) uint64 {
+	stat := info.Sys().(*syscall.Stat_t)
+	return uint64(max(0, stat.Size, stat.Blocks*512))
+}
diff --git a/pkg/osutil/osutil_bsd.go b/pkg/osutil/osutil_nonlinux.go
index b26c91ff7..1d3ee8b82 100644
--- a/pkg/osutil/osutil_bsd.go
+++ b/pkg/osutil/osutil_nonlinux.go
@@ -1,11 +1,12 @@
-// Copyright 2017 syzkaller project authors. All rights reserved.
+// Copyright 2026 syzkaller project authors. All rights reserved.
 // Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
 
-//go:build freebsd || netbsd || openbsd
+//go:build !linux
 
 package osutil
 
 import (
+	"io/fs"
 	"os"
 	"os/exec"
 	"time"
@@ -39,3 +40,7 @@ func setPdeathsig(cmd *exec.Cmd, hardKill bool) {
 
 func killPgroup(cmd *exec.Cmd) {
 }
+
+func sysDiskUsage(info fs.FileInfo) uint64 {
+	return uint64(max(0, info.Size()))
+}
diff --git a/pkg/osutil/osutil_test.go b/pkg/osutil/osutil_test.go
index 4d9bf4cf8..460cc85ca 100644
--- a/pkg/osutil/osutil_test.go
+++ b/pkg/osutil/osutil_test.go
@@ -4,6 +4,7 @@
 package osutil
 
 import (
+	"bytes"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -150,3 +151,44 @@ func TestReadWriteJSON(t *testing.T) {
 		t.Fatal(diff)
 	}
 }
+
+func TestDiskUsage(t *testing.T) {
+	dir := t.TempDir()
+	var currentUsage uint64
+	expectUsage := func(minIncrease, maxIncrease uint64) {
+		usage, err := DiskUsage(dir)
+		if err != nil {
+			t.Fatal(err)
+		}
+		expectMin := currentUsage + minIncrease
+		expectMax := currentUsage + maxIncrease
+		t.Logf("got usage %v when expected (%v, %v)", usage, expectMin, expectMax)
+		if usage <= expectMin || usage >= expectMax {
+			t.Fatalf("bad usage %v, expect (%v, %v)", usage, expectMin, expectMax)
+		}
+		currentUsage = usage
+	}
+	expectUsage(1, 5<<10)
+	if err := MkdirAll(filepath.Join(dir, "nested")); err != nil {
+		t.Fatal(err)
+	}
+	expectUsage(1, 5<<10)
+	if err := WriteFile(filepath.Join(dir, "nested", "foo"), bytes.Repeat([]byte{'a'}, 1<<10)); err != nil {
+		t.Fatal(err)
+	}
+	expectUsage(1<<10, 5<<10)
+	if err := WriteFile(filepath.Join(dir, "nested", "bar"), bytes.Repeat([]byte{'a'}, 10<<10)); err != nil {
+		t.Fatal(err)
+	}
+	expectUsage(10<<10, 14<<10)
+	// Symlinks must not be counted twice.
+	if err := os.Symlink(filepath.Join(dir, "nested"), filepath.Join(dir, "dirlink")); err != nil {
+		t.Fatal(err)
+	}
+	expectUsage(1, 1<<10)
+
+	if err := os.Symlink(filepath.Join(dir, "nested", "bar"), filepath.Join(dir, "filelink")); err != nil {
+		t.Fatal(err)
+	}
+	expectUsage(1, 1<<10)
+}
diff --git a/pkg/osutil/osutil_windows.go b/pkg/osutil/osutil_windows.go
index 03e729e83..db9f56efa 100644
--- a/pkg/osutil/osutil_windows.go
+++ b/pkg/osutil/osutil_windows.go
@@ -5,43 +5,12 @@ package osutil
 
 import (
 	"os"
-	"os/exec"
 	"syscall"
-	"time"
 )
 
-func creationTime(fi os.FileInfo) time.Time {
-	return time.Time{}
-}
-
 func HandleInterrupts(shutdown chan struct{}) {
 }
 
-func RemoveAll(dir string) error {
-	return os.RemoveAll(dir)
-}
-
-func SystemMemorySize() uint64 {
-	return 0
-}
-
-func prolongPipe(r, w *os.File) {
-}
-
 func ProcessExitStatus(ps *os.ProcessState) int {
 	return ps.Sys().(syscall.WaitStatus).ExitStatus()
 }
-
-func Sandbox(cmd *exec.Cmd, user, net bool) error {
-	return nil
-}
-
-func SandboxChown(file string) error {
-	return nil
-}
-
-func setPdeathsig(cmd *exec.Cmd, hardKill bool) {
-}
-
-func killPgroup(cmd *exec.Cmd) {
-}