elua: fork impl for windows

src/bin/elua/fork_win.c

@@ -0,0 +1,159 @@
+/* an implementation of fork for Windows */
+
+#include <windows.h>
+#include <setjmp.h>
+
+typedef struct _OBJECT_ATTRIBUTES {
+    ULONG Length;
+    HANDLE RootDirectory;
+    PVOID ObjectName;
+    ULONG Attributes;
+    PVOID SecurityDescriptor;
+    PVOID SecurityQualityOfService;
+} OBJECT_ATTRIBUTES, *POBJECT_ATTRIBUTES;
+
+typedef enum _MEMORY_INFORMATION_ {
+    MemoryBasicInformation,
+    MemoryWorkingSetList,
+    MemorySectionName,
+    MemoryBasicVlmInformation
+} MEMORY_INFORMATION_CLASS;
+
+typedef struct _CLIENT_ID {
+    HANDLE UniqueProcess;
+    HANDLE UniqueThread;
+} CLIENT_ID, *PCLIENT_ID;
+
+typedef struct _USER_STACK {
+    PVOID FixedStackBase;
+    PVOID FixedStackLimit;
+    PVOID ExpandableStackBase;
+    PVOID ExpandableStackLimit;
+    PVOID ExpandableStackBottom;
+} USER_STACK, *PUSER_STACK;
+
+typedef LONG KPRIORITY;
+typedef ULONG_PTR KAFFINITY;
+
+typedef struct _THREAD_BASIC_INFORMATION {
+    LONG                ExitStatus;
+    PVOID                   TebBaseAddress;
+    CLIENT_ID               ClientId;
+    KAFFINITY               AffinityMask;
+    KPRIORITY               Priority;
+    KPRIORITY               BasePriority;
+} THREAD_BASIC_INFORMATION, *PTHREAD_BASIC_INFORMATION;
+
+typedef enum _SYSTEM_INFORMATION_CLASS {
+    SystemHandleInformation = 0x10
+} SYSTEM_INFORMATION_CLASS;
+
+typedef LONG (NTAPI *ZwWriteVirtualMemory_t)(IN HANDLE,
+    IN PVOID, IN PVOID, IN ULONG, OUT PULONG OPTIONAL);
+
+typedef LONG (NTAPI *ZwCreateProcess_t)(OUT PHANDLE,
+    IN ACCESS_MASK, IN POBJECT_ATTRIBUTES, IN HANDLE, IN BOOLEAN,
+    IN HANDLE OPTIONAL, IN HANDLE OPTIONAL, IN HANDLE OPTIONAL);
+
+typedef LONG (WINAPI *ZwQuerySystemInformation_t)(SYSTEM_INFORMATION_CLASS,
+    PVOID, ULONG, PULONG);
+
+typedef LONG (NTAPI *ZwQueryVirtualMemory_t)(IN HANDLE,
+    IN PVOID, IN MEMORY_INFORMATION_CLASS, OUT PVOID, IN ULONG,
+    OUT PULONG OPTIONAL);
+
+typedef LONG (NTAPI *ZwGetContextThread_t)(IN HANDLE,
+    OUT PCONTEXT);
+
+typedef LONG (NTAPI *ZwCreateThread_t)(OUT PHANDLE,
+    IN ACCESS_MASK, IN POBJECT_ATTRIBUTES, IN HANDLE, OUT PCLIENT_ID,
+    IN PCONTEXT, IN PUSER_STACK, IN BOOLEAN);
+
+typedef LONG (NTAPI *ZwResumeThread_t)(IN HANDLE, OUT PULONG OPTIONAL);
+typedef LONG (NTAPI *ZwClose_t)(IN HANDLE);
+typedef LONG (NTAPI *ZwQueryInformationThread_t)(IN HANDLE,
+    IN THREAD_INFORMATION_CLASS, OUT PVOID, IN ULONG, OUT PULONG OPTIONAL);
+
+static ZwCreateProcess_t          ZwCreateProcess;
+static ZwQuerySystemInformation_t ZwQuerySystemInformation;
+static ZwQueryVirtualMemory_t     ZwQueryVirtualMemory;
+static ZwCreateThread_t           ZwCreateThread;
+static ZwGetContextThread_t       ZwGetContextThread;
+static ZwResumeThread_t           ZwResumeThread;
+static ZwClose_t                  ZwClose;
+static ZwQueryInformationThread_t ZwQueryInformationThread;
+static ZwWriteVirtualMemory_t     ZwWriteVirtualMemory;
+
+static jmp_buf jenv;
+static int child_entry(void) {
+    longjmp(jenv, 1);
+    return 0;
+}
+
+static int init_ntdll(void) {
+    HMODULE ntdll = GetModuleHandle("ntdll");
+    if (!ntdll) return 0;
+
+#define GETPROC(name) name = (name##_t)GetProcAddress(ntdll, #name)
+
+    GETPROC(ZwCreateProcess);
+    GETPROC(ZwQuerySystemInformation);
+    GETPROC(ZwQueryVirtualMemory);
+    GETPROC(ZwCreateThread);
+    GETPROC(ZwGetContextThread);
+    GETPROC(ZwResumeThread);
+    GETPROC(ZwQueryInformationThread);
+    GETPROC(ZwWriteVirtualMemory);
+    GETPROC(ZwClose);
+
+    return !!ZwCreateProcess;
+}
+
+int fork_win(void) {
+    if (setjmp(jenv)) return 0;
+    if (!ZwCreateProcess && !init_ntdll()) return -1;
+
+    HANDLE hproc = 0, hthread = 0;
+    OBJECT_ATTRIBUTES oa = { sizeof(oa) };
+    ZwCreateProcess(&hproc, PROCESS_ALL_ACCESS, &oa, (HANDLE)-1, TRUE, 0, 0, 0);
+
+    CONTEXT context = { CONTEXT_FULL | CONTEXT_DEBUG_REGISTERS
+        | CONTEXT_FLOATING_POINT };
+
+    ZwGetContextThread((HANDLE)-2, &context);
+
+    MEMORY_BASIC_INFORMATION mbi;
+
+#if _WIN64
+    context.Rip = (ULONG)child_entry;
+    ZwQueryVirtualMemory((HANDLE)-1, (PVOID)context.Rsp, MemoryBasicInformation,
+        &mbi, sizeof(mbi), 0);
+#else
+    context.Eip = (ULONG)child_entry;
+    ZwQueryVirtualMemory((HANDLE)-1, (PVOID)context.Esp, MemoryBasicInformation,
+        &mbi, sizeof(mbi), 0);
+#endif
+
+    USER_STACK stack = { 0, 0, (PCHAR)mbi.BaseAddress + mbi.RegionSize,
+        mbi.BaseAddress, mbi.AllocationBase };
+    CLIENT_ID cid;
+
+    ZwCreateThread(&hthread, THREAD_ALL_ACCESS, &oa, hproc, &cid, &context,
+        &stack, TRUE);
+
+    THREAD_BASIC_INFORMATION tbi;
+    ZwQueryInformationThread((HANDLE)-2, ThreadMemoryPriority, &tbi,
+        sizeof(tbi), 0);
+    PNT_TIB tib = (PNT_TIB)tbi.TebBaseAddress;
+    ZwQueryInformationThread(hthread, ThreadMemoryPriority, &tbi,
+        sizeof(tbi), 0);
+    ZwWriteVirtualMemory(hproc, tbi.TebBaseAddress, &tib->ExceptionList,
+        sizeof(tib->ExceptionList), 0);
+
+    ZwResumeThread(hthread, 0);
+
+    ZwClose(hthread);
+    ZwClose(hproc);
+
+    return (int)cid.UniqueProcess;
+}

src/bin/elua/main.c

@@ -5,6 +5,9 @@
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#else
+int fork_win(void);
+#define fork fork_win;
 #endif
 
 #include "main.h"