From 09022b6d70ad16737964e58db039aac00a1488ea Mon Sep 17 00:00:00 2001
From: NAKAMURA Usaku <usa@ruby-lang.org>
Date: Tue, 30 Apr 2019 03:32:41 +0900
Subject: Use CreateToolhelp32Snapshot instead of NtQueryInformationProcess to
 get ppid on Windows

Try to get rid of a spec error.
---
 win32/win32.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'win32/win32.c')

diff --git a/win32/win32.c b/win32/win32.c
index d28bd56452..2e3f6c4fe0 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -42,6 +42,7 @@
 #include <shlobj.h>
 #include <mbstring.h>
 #include <shlwapi.h>
+#include <tlhelp32.h>
 #if _MSC_VER >= 1400
 #include <crtdbg.h>
 #include <rtcapi.h>
@@ -6139,6 +6140,26 @@ rb_w32_getppid(void)
     static query_func *pNtQueryInformationProcess = (query_func *)-1;
     rb_pid_t ppid = 0;
 
+    HANDLE hSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+    if (hSnap != INVALID_HANDLE_VALUE) {
+	BOOL ok;
+	PROCESSENTRY32 pe;
+	DWORD pid = GetCurrentProcessId();
+	pe.dwSize = sizeof(pe);
+	ok = Process32First(hSnap, &pe);
+	while (ok) {
+	    if (pe.th32ProcessID == pid) {
+		ppid = (rb_pid_t)pe.th32ParentProcessID;
+		break;
+	    }
+	    ok = Process32Next(hSnap, &pe);
+	}
+	CloseHandle(hSnap);
+	if (ppid != 0) {
+	    return ppid;
+	}
+    }
+
     if (pNtQueryInformationProcess == (query_func *)-1)
 	pNtQueryInformationProcess = (query_func *)get_proc_address("ntdll.dll", "NtQueryInformationProcess", NULL);
     if (pNtQueryInformationProcess) {
-- 
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