StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
14649973
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
3
CommunityOwnedDate
CreationDate
2013-02-01T15:48:19.170
FavoriteCount
0
LastActivityDate
2013-02-01T16:02:22.387
LastEditDate
2013-02-01T16:02:22.387
LastEditorUserId
985841
OwnerUserId
985841
ParentId
985281
PostTypeId
2
Score
15
ViewCount
0
LastEditorDisplayName
text
Body
<p>People have tried to implement fork on Windows. This is the closest thing to it I can find:</p> <p>Taken from: <a href="http://doxygen.scilab.org/5.3/d0/d8f/forkWindows_8c_source.html#l00216">http://doxygen.scilab.org/5.3/d0/d8f/forkWindows_8c_source.html#l00216</a></p> <pre><code>static BOOL haveLoadedFunctionsForFork(void); int fork(void) { HANDLE hProcess = 0, hThread = 0; OBJECT_ATTRIBUTES oa = { sizeof(oa) }; MEMORY_BASIC_INFORMATION mbi; CLIENT_ID cid; USER_STACK stack; PNT_TIB tib; THREAD_BASIC_INFORMATION tbi; CONTEXT context = { CONTEXT_FULL | CONTEXT_DEBUG_REGISTERS | CONTEXT_FLOATING_POINT }; if (setjmp(jenv) != 0) return 0; /* return as a child */ /* check whether the entry points are initilized and get them if necessary */ if (!ZwCreateProcess && !haveLoadedFunctionsForFork()) return -1; /* create forked process */ ZwCreateProcess(&hProcess, PROCESS_ALL_ACCESS, &oa, NtCurrentProcess(), TRUE, 0, 0, 0); /* set the Eip for the child process to our child function */ ZwGetContextThread(NtCurrentThread(), &context); /* In x64 the Eip and Esp are not present, their x64 counterparts are Rip and Rsp respectively. */ #if _WIN64 context.Rip = (ULONG)child_entry; #else context.Eip = (ULONG)child_entry; #endif #if _WIN64 ZwQueryVirtualMemory(NtCurrentProcess(), (PVOID)context.Rsp, MemoryBasicInformation, &mbi, sizeof mbi, 0); #else ZwQueryVirtualMemory(NtCurrentProcess(), (PVOID)context.Esp, MemoryBasicInformation, &mbi, sizeof mbi, 0); #endif stack.FixedStackBase = 0; stack.FixedStackLimit = 0; stack.ExpandableStackBase = (PCHAR)mbi.BaseAddress + mbi.RegionSize; stack.ExpandableStackLimit = mbi.BaseAddress; stack.ExpandableStackBottom = mbi.AllocationBase; /* create thread using the modified context and stack */ ZwCreateThread(&hThread, THREAD_ALL_ACCESS, &oa, hProcess, &cid, &context, &stack, TRUE); /* copy exception table */ ZwQueryInformationThread(NtCurrentThread(), ThreadBasicInformation, &tbi, sizeof tbi, 0); tib = (PNT_TIB)tbi.TebBaseAddress; ZwQueryInformationThread(hThread, ThreadBasicInformation, &tbi, sizeof tbi, 0); ZwWriteVirtualMemory(hProcess, tbi.TebBaseAddress, &tib->ExceptionList, sizeof tib->ExceptionList, 0); /* start (resume really) the child */ ZwResumeThread(hThread, 0); /* clean up */ ZwClose(hThread); ZwClose(hProcess); /* exit with child's pid */ return (int)cid.UniqueProcess; } static BOOL haveLoadedFunctionsForFork(void) { HANDLE ntdll = GetModuleHandle("ntdll"); if (ntdll == NULL) return FALSE; if (ZwCreateProcess && ZwQuerySystemInformation && ZwQueryVirtualMemory && ZwCreateThread && ZwGetContextThread && ZwResumeThread && ZwQueryInformationThread && ZwWriteVirtualMemory && ZwClose) { return TRUE; } ZwCreateProcess = (ZwCreateProcess_t) GetProcAddress(ntdll, "ZwCreateProcess"); ZwQuerySystemInformation = (ZwQuerySystemInformation_t) GetProcAddress(ntdll, "ZwQuerySystemInformation"); ZwQueryVirtualMemory = (ZwQueryVirtualMemory_t) GetProcAddress(ntdll, "ZwQueryVirtualMemory"); ZwCreateThread = (ZwCreateThread_t) GetProcAddress(ntdll, "ZwCreateThread"); ZwGetContextThread = (ZwGetContextThread_t) GetProcAddress(ntdll, "ZwGetContextThread"); ZwResumeThread = (ZwResumeThread_t) GetProcAddress(ntdll, "ZwResumeThread"); ZwQueryInformationThread = (ZwQueryInformationThread_t) GetProcAddress(ntdll, "ZwQueryInformationThread"); ZwWriteVirtualMemory = (ZwWriteVirtualMemory_t) GetProcAddress(ntdll, "ZwWriteVirtualMemory"); ZwClose = (ZwClose_t) GetProcAddress(ntdll, "ZwClose"); if (ZwCreateProcess && ZwQuerySystemInformation && ZwQueryVirtualMemory && ZwCreateThread && ZwGetContextThread && ZwResumeThread && ZwQueryInformationThread && ZwWriteVirtualMemory && ZwClose) { return TRUE; } else { ZwCreateProcess = NULL; ZwQuerySystemInformation = NULL; ZwQueryVirtualMemory = NULL; ZwCreateThread = NULL; ZwGetContextThread = NULL; ZwResumeThread = NULL; ZwQueryInformationThread = NULL; ZwWriteVirtualMemory = NULL; ZwClose = NULL; } return FALSE; } </code></pre>
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POWhat is the closest thing windows has to fork()?
  singulars
  PostTypePostTypeId
  PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. USEric des Courtis
UserOwnerUserId
1. USEric des Courtis
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. VO
  singulars
  PostPostId
  PO
  UserUserId
  This table or related slice is empty.
  VoteTypeVoteTypeId
  VTUpMod
2. VO
  singulars
  PostPostId
  PO
  UserUserId
  This table or related slice is empty.
  VoteTypeVoteTypeId
  VTUpMod
3. VO
  singulars
  PostPostId
  PO
  UserUserId
  This table or related slice is empty.
  VoteTypeVoteTypeId
  VTUpMod
CommentsPostId
1. CONote that most of the error checking is missing - e.g. ZwCreateThread returns an NTSTATUS value which can be checked using the SUCCEEDED and FAILED macros.
  singulars
  PostPostId
  PO
  UserUserId
  USBCran

Querying!

Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.