From 9ccdebcd96cfbdea122752d1b6bd45f507f4c7c5 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Fri, 22 May 2026 22:21:54 +0300
Subject: [PATCH] LibC: Implement/fix mk{,o}stemp{,s}

---
 userspace/libraries/LibC/include/stdlib.h |  6 +-
 userspace/libraries/LibC/stdlib.cpp       | 78 +++++++++++++++--------
 2 files changed, 56 insertions(+), 28 deletions(-)

diff --git a/userspace/libraries/LibC/include/stdlib.h b/userspace/libraries/LibC/include/stdlib.h
index 3e1acb47..aecf2854 100644
--- a/userspace/libraries/LibC/include/stdlib.h
+++ b/userspace/libraries/LibC/include/stdlib.h
@@ -75,8 +75,8 @@ int					mblen(const char* s, size_t n);
 size_t				mbstowcs(wchar_t* __restrict pwcs, const char* __restrict s, size_t n);
 int					mbtowc(wchar_t* __restrict pwc, const char* __restrict s, size_t n);
 char*				mkdtemp(char* _template);
-char*				mktemp(char* _template);
 int					mkstemp(char* _template);
+int					mkostemp(char* _template, int flags);
 long				mrand48(void);
 long				nrand48(unsigned short xsubi[3]);
 int					posix_memalign(void** memptr, size_t alignment, size_t size);
@@ -109,6 +109,10 @@ int					unsetenv(const char* name);
 size_t				wcstombs(char* __restrict s, const wchar_t* __restrict pwcs, size_t n);
 int					wctomb(char* s, wchar_t wchar);
 
+char*	mktemp(char* _template);
+int		mkstemps(char* _template, int suffixlen);
+int		mkostemps(char* _template, int suffixlen, int flags);
+
 __END_DECLS
 
 #endif
diff --git a/userspace/libraries/LibC/stdlib.cpp b/userspace/libraries/LibC/stdlib.cpp
index 9a0e5c50..265dd4ef 100644
--- a/userspace/libraries/LibC/stdlib.cpp
+++ b/userspace/libraries/LibC/stdlib.cpp
@@ -475,31 +475,36 @@ int system(const char* command)
 	return stat_val;
 }
 
-static size_t temp_template_count_x(const char* _template)
+static void randomize_temp(char* buffer)
 {
-	const size_t len = strlen(_template);
-	for (size_t i = 0; i < len; i++)
-		if (_template[len - i - 1] != 'X')
-			return i;
-	return len;
+	// FIXME: don't use rand()
+	const uint32_t value = rand() & 0xFFFFFF;
+	sprintf(buffer, "%06x", value);
 }
 
-static void generate_temp_template(char* _template, size_t x_count)
+static char* validate_temp_template(char* _template, int suffixlen)
 {
-	const size_t len = strlen(_template);
-	for (size_t i = 0; i < x_count; i++)
+	const size_t length = strlen(_template);
+	if (suffixlen < 0 || length < static_cast<size_t>(suffixlen + 6))
 	{
-		const uint8_t nibble = rand() & 0xF;
-		_template[len - i - 1] = (nibble < 10)
-			? ('0' + nibble)
-			: ('a' + nibble - 10);
+		errno = EINVAL;
+		return nullptr;
 	}
+
+	char* xptr = _template + length - suffixlen - 6;
+	if (memcmp(xptr, "XXXXXX", 6) != 0)
+	{
+		errno = EINVAL;
+		return nullptr;
+	}
+
+	return xptr;
 }
 
 char* mktemp(char* _template)
 {
-	const size_t x_count = temp_template_count_x(_template);
-	if (x_count < 6)
+	char* xptr = validate_temp_template(_template, 0);
+	if (xptr == nullptr)
 	{
 		errno = EINVAL;
 		_template[0] = '\0';
@@ -508,18 +513,22 @@ char* mktemp(char* _template)
 
 	for (;;)
 	{
-		generate_temp_template(_template, x_count);
+		randomize_temp(xptr);
 
 		struct stat st;
-		if (stat(_template, &st) == 0)
+		if (stat(_template, &st) == -1)
+		{
+			if (errno != ENOENT)
+				_template[0] = '\0';
 			return _template;
+		}
 	}
 }
 
 char* mkdtemp(char* _template)
 {
-	const size_t x_count = temp_template_count_x(_template);
-	if (x_count < 6)
+	char* xptr = validate_temp_template(_template, 0);
+	if (xptr == nullptr)
 	{
 		errno = EINVAL;
 		return nullptr;
@@ -527,8 +536,7 @@ char* mkdtemp(char* _template)
 
 	for (;;)
 	{
-		generate_temp_template(_template, x_count);
-
+		randomize_temp(xptr);
 		if (mkdir(_template, S_IRUSR | S_IWUSR | S_IXUSR) != -1)
 			return _template;
 		if (errno != EEXIST)
@@ -538,8 +546,26 @@ char* mkdtemp(char* _template)
 
 int mkstemp(char* _template)
 {
-	const size_t x_count = temp_template_count_x(_template);
-	if (x_count < 6)
+	return mkostemps(_template, 0, 0);
+}
+
+int mkostemp(char* _template, int flags)
+{
+	return mkostemps(_template, 0, flags);
+}
+
+int mkstemps(char* _template, int suffixlen)
+{
+	return mkostemps(_template, suffixlen, 0);
+}
+
+int mkostemps(char* _template, int suffixlen, int flags)
+{
+	flags &= O_APPEND | O_CLOEXEC | O_SYNC;
+	flags |= O_RDWR | O_CREAT | O_EXCL;
+
+	char* xptr = validate_temp_template(_template, suffixlen);
+	if (xptr == nullptr)
 	{
 		errno = EINVAL;
 		return -1;
@@ -547,10 +573,8 @@ int mkstemp(char* _template)
 
 	for (;;)
 	{
-		generate_temp_template(_template, x_count);
-
-		int fd = open(_template, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
-		if (fd != -1)
+		randomize_temp(xptr);
+		if (int fd = open(_template, flags, 0600); fd != -1)
 			return fd;
 		if (errno != EEXIST)
 			return -1;