Delete .node files from bun build --compile after dlopen (oven-sh#19551)

Co-authored-by: 190n <ben@bun.sh>

Author: Jarred-Sumner

src/bun.js/bindings/BunProcess.cpp

@@ -69,6 +69,7 @@
 #include <sys/types.h>
 #include <pwd.h>
 #include <grp.h>
+#include <mimalloc.h>
 #else
 #include <uv.h>
 #include <io.h>
@@ -361,6 +362,9 @@ static char* toFileURI(std::span<const char> span)
 
 extern "C" size_t Bun__process_dlopen_count;
 
+// "Fire and forget" wrapper around unlink for c usage that handles EINTR
+extern "C" void Bun__unlink(const char*, size_t);
+
 extern "C" void CrashHandler__setDlOpenAction(const char* action);
 extern "C" bool Bun__VM__allowAddons(void* vm);
 
@@ -408,11 +412,13 @@ JSC_DEFINE_HOST_FUNCTION(Process_functionDlopen, (JSC::JSGlobalObject * globalOb
     Strong<JSC::JSObject> strongModule = { vm, moduleObject };
 
     WTF::String filename = callFrame->uncheckedArgument(1).toWTFString(globalObject);
-    if (filename.isEmpty()) {
+
+    if (filename.isEmpty() && !scope.exception()) {
         JSC::throwTypeError(globalObject, scope, "dlopen requires a non-empty string as the second argument"_s);
-        return {};
     }
 
+    RETURN_IF_EXCEPTION(scope, {});
+
     if (filename.startsWith("file://"_s)) {
         WTF::URL fileURL = WTF::URL(filename);
         if (!fileURL.isValid() || !fileURL.protocolIsFile()) {
@@ -423,29 +429,82 @@ JSC_DEFINE_HOST_FUNCTION(Process_functionDlopen, (JSC::JSGlobalObject * globalOb
         filename = fileURL.fileSystemPath();
     }
 
+    CString utf8;
+
     // Support embedded .node files
     // See StandaloneModuleGraph.zig for what this "$bunfs" thing is
 #if OS(WINDOWS)
 #define StandaloneModuleGraph__base_path "B:/~BUN/"_s
 #else
 #define StandaloneModuleGraph__base_path "/$bunfs/"_s
 #endif
+    bool deleteAfter = false;
     if (filename.startsWith(StandaloneModuleGraph__base_path)) {
         BunString bunStr = Bun::toString(filename);
         if (Bun__resolveEmbeddedNodeFile(globalObject->bunVM(), &bunStr)) {
             filename = bunStr.toWTFString(BunString::ZeroCopy);
+            deleteAfter = !filename.startsWith("/proc/"_s);
         }
     }
 
     RETURN_IF_EXCEPTION(scope, {});
+
+    // For bun build --compile, we copy the .node file to a temp directory.
+    // It's best to delete it as soon as we can.
+    // https://github.com/oven-sh/bun/issues/19550
+    const auto tryToDeleteIfNecessary = [&]() {
+#if OS(WINDOWS)
+        if (deleteAfter) {
+            // Only call it once
+            deleteAfter = false;
+            if (filename.is8Bit()) {
+                filename.convertTo16Bit();
+            }
+
+            // Convert to 16-bit with a sentinel zero value.
+            auto span = filename.span16();
+            auto dupeZ = new wchar_t[span.size() + 1];
+            if (dupeZ) {
+                memcpy(dupeZ, span.data(), span.size_bytes());
+                dupeZ[span.size()] = L'\0';
+
+                // We can't immediately delete the file on Windows.
+                // Instead, we mark it for deletion on reboot.
+                MoveFileExW(
+                    dupeZ,
+                    NULL, // NULL destination means delete
+                    MOVEFILE_DELAY_UNTIL_REBOOT);
+                delete[] dupeZ;
+            }
+        }
+#else
+        if (deleteAfter) {
+            deleteAfter = false;
+            Bun__unlink(utf8.data(), utf8.length());
+        }
+#endif
+    };
+
+    {
+        auto utf8_filename = filename.tryGetUTF8(ConversionMode::LenientConversion);
+        if (UNLIKELY(!utf8_filename)) {
+            JSC::throwTypeError(globalObject, scope, "process.dlopen requires a valid UTF-8 string for the filename"_s);
+            return {};
+        }
+        utf8 = *utf8_filename;
+    }
+
 #if OS(WINDOWS)
     BunString filename_str = Bun::toString(filename);
     HMODULE handle = Bun__LoadLibraryBunString(&filename_str);
+
+// On Windows, we use GetLastError() for error messages, so we can only delete after checking for errors
 #else
-    CString utf8 = filename.utf8();
     CrashHandler__setDlOpenAction(utf8.data());
     void* handle = dlopen(utf8.data(), RTLD_LAZY);
     CrashHandler__setDlOpenAction(nullptr);
+
+    tryToDeleteIfNecessary();
 #endif
 
     globalObject->m_pendingNapiModuleDlopenHandle = handle;
@@ -482,12 +541,19 @@ JSC_DEFINE_HOST_FUNCTION(Process_functionDlopen, (JSC::JSGlobalObject * globalOb
         WTF::String msg = errorBuilder.toString();
         if (messageBuffer)
             LocalFree(messageBuffer); // Free the buffer allocated by FormatMessageW
+
+        // Since we're relying on LastError(), we have to delete after checking for errors
+        tryToDeleteIfNecessary();
 #else
         WTF::String msg = WTF::String::fromUTF8(dlerror());
 #endif
         return throwError(globalObject, scope, ErrorCode::ERR_DLOPEN_FAILED, msg);
     }
 
+#if OS(WINDOWS)
+    tryToDeleteIfNecessary();
+#endif
+
     if (callCountAtStart != globalObject->napiModuleRegisterCallCount) {
         JSValue resultValue = globalObject->m_pendingNapiModuleAndExports[0].get();
         globalObject->napiModuleRegisterCallCount = 0;
@@ -528,7 +594,9 @@ JSC_DEFINE_HOST_FUNCTION(Process_functionDlopen, (JSC::JSGlobalObject * globalOb
         dlclose(handle);
 #endif
 
-        JSC::throwTypeError(globalObject, scope, "symbol 'napi_register_module_v1' not found in native module. Is this a Node API (napi) module?"_s);
+        if (LIKELY(!scope.exception())) {
+            JSC::throwTypeError(globalObject, scope, "symbol 'napi_register_module_v1' not found in native module. Is this a Node API (napi) module?"_s);
+        }
         return {};
     }
 
@@ -542,7 +610,7 @@ JSC_DEFINE_HOST_FUNCTION(Process_functionDlopen, (JSC::JSGlobalObject * globalOb
 
     EncodedJSValue exportsValue = JSC::JSValue::encode(exports);
 
-    char* filename_cstr = toFileURI(filename.utf8().span());
+    char* filename_cstr = toFileURI(utf8.span());
 
     napi_module nmodule {
         .nm_version = module_version,

src/sys.zig

@@ -4611,6 +4611,11 @@ export fn Bun__errnoName(err: c_int) ?[*:0]const u8 {
     return @tagName(SystemErrno.init(err) orelse return null);
 }
 
+/// Small "fire and forget" wrapper around unlink for c usage that handles EINTR, windows path conversion, etc.
+export fn Bun__unlink(ptr: [*:0]const u8, len: usize) void {
+    _ = unlink(ptr[0..len :0]);
+}
+
 // TODO: this is wrong on Windows
 const libc_stat = bun.Stat;
 const Stat = std.fs.File.Stat;

test/napi/napi.test.ts

@@ -1,5 +1,6 @@
 import { spawnSync } from "bun";
 import { beforeAll, describe, expect, it } from "bun:test";
+import { readdirSync } from "fs";
 import { bunEnv, bunExe, tempDirWithFiles } from "harness";
 import { join } from "path";
 
@@ -90,18 +91,23 @@ describe("napi", () => {
               stderr: "inherit",
             });
             expect(build.success).toBeTrue();
-
+            const tmpdir = tempDirWithFiles("should-be-empty-except", {});
             const result = spawnSync({
               cmd: [exe, "self"],
-              env: bunEnv,
+              env: { ...bunEnv, BUN_TMPDIR: tmpdir },
               stdin: "inherit",
               stderr: "inherit",
               stdout: "pipe",
             });
             const stdout = result.stdout.toString().trim();
-
             expect(stdout).toBe("hello world!");
             expect(result.success).toBeTrue();
+            if (process.platform !== "win32") {
+              expect(readdirSync(tmpdir), "bun should clean up .node files").toBeEmpty();
+            } else {
+              // On Windows, we have to mark it for deletion on reboot.
+              // Not clear how to test for that.
+            }
           },
           10 * 1000,
         );