From 98889ffbbaff392eebabcbe3719b4daf70f40b65 Mon Sep 17 00:00:00 2001
From: Boming Zhang <bomingzh@sjtu.edu.cn>
Date: Wed, 22 Jul 2026 23:56:41 -0700
Subject: [PATCH] feat(sandbox): add tar-based copyIn to bypass SOCK_SEQPACKET
 file limit

---
 internal/executor/sandbox/executor.go | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/internal/executor/sandbox/executor.go b/internal/executor/sandbox/executor.go
index d8d3e4f..6d0b7b5 100644
--- a/internal/executor/sandbox/executor.go
+++ b/internal/executor/sandbox/executor.go
@@ -52,15 +52,16 @@ func prepareTar(cmds []stage.Cmd) (bool, []byte) {
 		if cmds[i].CopyInDir != "" &&
 			estimateCopyInSize(&cmds[i]) >= tarThreshold {
 			tarData, keysInTar := createCopyInTar(&cmds[i])
+			if tarData == nil {
+				return false, nil
+			}
+			slog.Debug("prepareTar", "tarSize", len(tarData), "keysInTar", len(keysInTar))
 			for j := range cmds {
 				cmds[j].CopyInDir = ""
 				for _, k := range keysInTar {
 					delete(cmds[j].CopyIn, k)
 				}
 			}
-			if tarData == nil {
-				return false, nil
-			}
 			return true, tarData
 		}
 	}
@@ -101,11 +102,11 @@ func (e *Sandbox) runWithTar(cmds []stage.Cmd, tarData []byte) ([]stage.Executor
 
 	tarFileName := "/w/__joj3_copyin.tar"
 	tarCmd := stage.Cmd{
-		Args:         []string{"/bin/tar", "xf", tarFileName, "-C", "/w"},
+		Args:         []string{"/bin/tar", "xf", tarFileName, "-C", "/w", "--no-same-owner"},
 		Env:          cmds[0].Env,
 		Stdin:        &stage.CmdFile{Content: strPtr("")},
-		Stdout:       &stage.CmdFile{Name: strPtr("__tar_stdout"), Max: int64Ptr(1)},
-		Stderr:       &stage.CmdFile{Name: strPtr("__tar_stderr"), Max: int64Ptr(1)},
+		Stdout:       &stage.CmdFile{Name: strPtr("__tar_stdout"), Max: int64Ptr(256)},
+		Stderr:       &stage.CmdFile{Name: strPtr("__tar_stderr"), Max: int64Ptr(256)},
 		CPULimit:     cmds[0].CPULimit,
 		ClockLimit:   cmds[0].ClockLimit,
 		MemoryLimit:  cmds[0].MemoryLimit,
@@ -116,7 +117,6 @@ func (e *Sandbox) runWithTar(cmds []stage.Cmd, tarData []byte) ([]stage.Executor
 		CopyIn: map[string]stage.CmdFile{
 			tarFileName: {FileID: &fid},
 		},
-		CopyOutCached: []string{tarFileName},
 	}
 
 	allCmds := append([]stage.Cmd{tarCmd}, cmds...)