From 8bd112f0e47c5d6eb35802fd310c38bff3fa8552 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?D=C3=A1vid=20Balatoni?=
 <40299962+dbalatoni13@users.noreply.github.com>
Date: Wed, 18 Jun 2025 00:12:39 +0200
Subject: [PATCH] Add GetTempFileNameA (#84)

---
 common.h         |  3 +++
 dll/kernel32.cpp | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/common.h b/common.h
index 64ad01c..0ac0157 100644
--- a/common.h
+++ b/common.h
@@ -55,6 +55,7 @@ typedef unsigned char BYTE;
 #define ERROR_HANDLE_EOF 38
 #define ERROR_NOT_SUPPORTED 50
 #define ERROR_INVALID_PARAMETER 87
+#define ERROR_BUFFER_OVERFLOW 111
 #define ERROR_INSUFFICIENT_BUFFER 122
 #define ERROR_NEGATIVE_SEEK 131
 #define ERROR_ALREADY_EXISTS 183
@@ -72,6 +73,8 @@ typedef int NTSTATUS;
 typedef int HRESULT;
 #define S_OK ((HRESULT)0x00000000)
 
+#define MAX_PATH (260)
+
 namespace wibo {
 	extern uint32_t lastError;
 	extern char **argv;
diff --git a/dll/kernel32.cpp b/dll/kernel32.cpp
index fc3567a..6d575a6 100644
--- a/dll/kernel32.cpp
+++ b/dll/kernel32.cpp
@@ -3,6 +3,7 @@
 #include "processes.h"
 #include "handles.h"
 #include <algorithm>
+#include <climits>
 #include <cstdlib>
 #include <ctype.h>
 #include <filesystem>
@@ -10,6 +11,7 @@
 #include <string>
 #include "strutil.h"
 #include <malloc.h>
+#include <random>
 #include <stdarg.h>
 #include <system_error>
 #include <sys/mman.h>
@@ -17,6 +19,7 @@
 #include <sys/wait.h>
 #include <spawn.h>
 #include <vector>
+#include <fcntl.h>
 
 typedef union _RTL_RUN_ONCE {
 	PVOID Ptr;
@@ -649,6 +652,46 @@ namespace kernel32 {
 		}
 	}
 
+	using random_shorts_engine = std::independent_bits_engine<std::default_random_engine, sizeof(unsigned short) * 8, unsigned short>;
+
+	unsigned int WIN_FUNC GetTempFileNameA(LPSTR lpPathName, LPSTR lpPrefixString, unsigned int uUnique, LPSTR lpTempFileName) {
+		DEBUG_LOG("GetTempFileNameA\n");
+		if (lpPathName == 0) {
+			return 0;
+		}
+		if (strlen(lpPathName) > MAX_PATH - 14) {
+			wibo::lastError = ERROR_BUFFER_OVERFLOW;
+			return 0;
+		}
+		char uniqueStr[20];
+		std::filesystem::path path;
+
+		if (uUnique == 0) {
+			std::random_device rd;
+			random_shorts_engine rse(rd());
+			while(true) {
+				uUnique = rse();
+				if (uUnique == 0) {
+					continue;
+				}
+				snprintf(uniqueStr, sizeof(uniqueStr), "%.3s%X.TMP", lpPrefixString, uUnique);
+				path = files::pathFromWindows(lpPathName) / uniqueStr;
+				// Atomically create it if it doesn't exist
+				int fd = open(path.c_str(), O_CREAT | O_EXCL | O_WRONLY, 0644);
+				if (fd >= 0) {
+					close(fd);
+					break;
+				}
+			}
+		}
+		else {
+			snprintf(uniqueStr, sizeof(uniqueStr), "%.3s%X.TMP", lpPrefixString, uUnique & 0xFFFF);
+			path = files::pathFromWindows(lpPathName) / uniqueStr;
+		}
+		strncpy(lpTempFileName, files::pathToWindows(path).c_str(), MAX_PATH);
+		return uUnique;
+	}
+
 	DWORD WIN_FUNC GetTempPathA(DWORD nBufferLength, LPSTR lpBuffer) {
 		DEBUG_LOG("GetTempPathA\n");
 
@@ -2368,6 +2411,7 @@ static void *resolveByName(const char *name) {
 	if (strcmp(name, "GetFileType") == 0) return (void *) kernel32::GetFileType;
 	if (strcmp(name, "FileTimeToLocalFileTime") == 0) return (void *) kernel32::FileTimeToLocalFileTime;
 	if (strcmp(name, "GetFileInformationByHandle") == 0) return (void *) kernel32::GetFileInformationByHandle;
+	if (strcmp(name, "GetTempFileNameA") == 0) return (void *) kernel32::GetTempFileNameA;
 	if (strcmp(name, "GetTempPathA") == 0) return (void *) kernel32::GetTempPathA;
 
 	// sysinfoapi.h