Add replacement helpers for strncpy[_s]

Portable without vulnerabilities.

include/dusk/string.hpp

@@ -0,0 +1,52 @@
+#ifndef DUSK_STRING_HPP
+#define DUSK_STRING_HPP
+
+#include "global.h"
+#include <cstring>
+#include <dolphin/os.h>
+
+namespace dusk {
+
+/**
+ * Copy a string to a fixed-size array.
+ * Truncates if the destination is not large enough, always inserts a null terminator (padding the remainder of the buffer with zeroes.)
+ */
+template <size_t BufSize>
+void SafeStringCopyTruncate(char (&buffer)[BufSize], const char* src) {
+    static_assert(BufSize > 0, "Target buffer cannot be size zero");
+
+    // Can't just use strncpy as I can't figure out how to selectively mute the warnings on MSVC.
+    // And can't use strncpy_s on MSVC  as it doesn't fill the entire buffer.
+    constexpr size_t copyBufSize = BufSize - 1;
+    const auto srcLen = strlen(src);
+    const auto copyLen = srcLen > copyBufSize ? copyBufSize : srcLen;
+    memcpy(buffer, src, copyLen);
+    memset(buffer + copyLen, 0, BufSize - copyLen);
+}
+
+/**
+ * Copy a string to a fixed-size array.
+ * Aborts if the destination is not large enough, always inserts a null terminator (padding the remainder of the buffer with zeroes.)
+ */
+template <size_t BufSize>
+void SafeStringCopy(char (&buffer)[BufSize], const char* src) {
+    static_assert(BufSize > 0, "Target buffer cannot be size zero");
+    if (buffer == src) {
+        CRASH("Cannot copy string to same buffer");
+    }
+
+    // Can't just use strncpy as I can't figure out how to selectively mute the warnings on MSVC.
+    // And can't use strncpy_s on MSVC as it doesn't fill the entire buffer.
+    constexpr size_t copyBufSize = BufSize - 1;
+    const auto srcLen = strlen(src);
+    if (srcLen > copyBufSize) {
+        CRASH("Destination buffer too small!");
+    }
+
+    memcpy(buffer, src, srcLen);
+    memset(buffer + srcLen, 0, BufSize - srcLen);
+}
+
+}
+
+#endif  // DUSK_STRING_HPP

libs/JSystem/src/JKernel/JKRHeap.cpp

@@ -15,6 +15,7 @@
 
 #include "JSystem/JUtility/JUTAssert.h"
 #include "JSystem/JUtility/JUTException.h"
+#include "dusk/string.hpp"
 #ifdef __MWERKS__
 #include <stdint.h>
 #else
@@ -701,9 +702,7 @@ JKRHeap* JKRHeap::getCurrentHeap() {
 }
 
 void JKRHeap::setName(const char* name) {
-    size_t len = strlen(name);
-    strncpy(mName, name, sizeof(mName) - 1);
-    mName[sizeof(mName) - 1] = '\0';
+    dusk::SafeStringCopyTruncate(mName, name);
 }
 
 void JKRHeap::setNamef(const char* fmt, ...) {

src/d/d_stage.cpp

@@ -21,6 +21,8 @@
 #include "m_Do/m_Do_Reset.h"
 #include <cstdio>
 #include <cstring>
+
+#include "dusk/string.hpp"
 #if TARGET_PC
 #include <format>
 #include <fmt/ranges.h>
@@ -154,7 +156,7 @@ void dStage_startStage_c::set(const char* i_Name, s8 i_RoomNo, s16 i_Point, s8 i
 #if TARGET_PC
     // UB fix.
     if (mName != i_Name) {
-        strncpy_s(mName, sizeof(mName), i_Name, sizeof(mName));
+        dusk::SafeStringCopy(mName, i_Name);
     }
 #else
     strcpy(mName, i_Name);