From 0364ffe446cf0dac43e1bca2427b6750a5edc8e2 Mon Sep 17 00:00:00 2001
From: Cody Tapscott <topolarity@tapscott.me>
Date: Thu, 26 Feb 2026 15:35:31 -0500
Subject: [PATCH] Fix `cbDest` argument of `StringCbPrintfW`

Microsoft has documented that this is the size of the destination buffer
in bytes, not characters.

PATH_MAX is already limited to 260 on Windows, so this mistake means
that paths longer than ~130 characters are truncated.
---
 lib/gks/ft.c     | 4 ++--
 lib/gks/plugin.c | 7 +++++--
 lib/gks/socket.c | 6 +++---
 lib/gr/stream.c  | 6 +++---
 4 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/lib/gks/ft.c b/lib/gks/ft.c
index 9e2ae7458..69c7c3326 100644
--- a/lib/gks/ft.c
+++ b/lib/gks/ft.c
@@ -234,7 +234,7 @@ static int ft_join_path(ft_path_char_t *result, size_t size, const ft_path_char_
       return 0;
     }
 
-  StringCbPrintfW(result, size, L"%ws%c%ws", first, delim, second);
+  StringCbPrintfW(result, size * sizeof(wchar_t), L"%ws%c%ws", first, delim, second);
   return 1;
 #else
   const char delim = '/';
@@ -728,7 +728,7 @@ static ft_path_char_t *gks_ft_get_font_path(const char *font_name, const char *f
   StringCbLengthW(prefix, MAXPATHLEN, &len);
   len += 2 * (7 + strlen(font_name) + strlen(font_file_extension) + 1);
   font_path = (ft_path_char_t *)gks_malloc(len * sizeof(ft_path_char_t));
-  StringCbPrintfW(font_path, MAXPATHLEN, L"%lS\\FONTS\\%S%S", prefix, font_name, font_file_extension);
+  StringCbPrintfW(font_path, len * sizeof(ft_path_char_t), L"%lS\\FONTS\\%S%S", prefix, font_name, font_file_extension);
 #else
   const char *prefix;
   char *font_path;
diff --git a/lib/gks/plugin.c b/lib/gks/plugin.c
index abc92ee1a..c7a55a147 100644
--- a/lib/gks/plugin.c
+++ b/lib/gks/plugin.c
@@ -49,8 +49,11 @@ static void *load_library(const char *name)
   handle = LoadLibrary(pathname);
   if (handle == NULL)
     {
-      GetEnvironmentVariableW(L"GRDIR", grdir, MAX_PATH);
-      StringCbPrintfW(w_pathname, MAX_PATH, L"%ws\\bin\\%S.%S", grdir, name, EXTENSION);
+      if (!GetEnvironmentVariableW(L"GRDIR", grdir, MAX_PATH))
+        {
+          MultiByteToWideChar(CP_UTF8, 0, GRDIR, -1, grdir, MAX_PATH);
+        }
+      StringCbPrintfW(w_pathname, sizeof(w_pathname), L"%ws\\bin\\%S.%S", grdir, name, EXTENSION);
       handle = LoadLibraryExW(w_pathname, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
       if (handle == NULL)
         {
diff --git a/lib/gks/socket.c b/lib/gks/socket.c
index dc80a03d9..ce1fb88dc 100644
--- a/lib/gks/socket.c
+++ b/lib/gks/socket.c
@@ -81,7 +81,7 @@ static DWORD WINAPI gksqt_thread(LPVOID parm)
   STARTUPINFOW startupInfo;
   PROCESS_INFORMATION processInformation;
 
-  StringCbPrintfW(w_cmd_line, CMD_LINE_LEN, L"cmd.exe /c \"%ls\"", cmd);
+  StringCbPrintfW(w_cmd_line, sizeof(w_cmd_line), L"cmd.exe /c \"%ls\"", cmd);
 
   if (!GetEnvironmentVariableW(L"WSLENV", buffer, BUFFER_LEN))
     {
@@ -305,11 +305,11 @@ static int open_socket(int wstype)
         {
           if (!GetEnvironmentVariableW(L"GRDIR", w_env, MAXPATHLEN))
             {
-              StringCbPrintfW(command, CMD_LINE_LEN, L"%S\\bin\\gksqt.exe", GRDIR);
+              StringCbPrintfW(command, sizeof(command), L"%S\\bin\\gksqt.exe", GRDIR);
             }
           else
             {
-              StringCbPrintfW(command, CMD_LINE_LEN, L"%ws\\bin\\gksqt.exe", w_env);
+              StringCbPrintfW(command, sizeof(command), L"%ws\\bin\\gksqt.exe", w_env);
             }
         }
 #else
diff --git a/lib/gr/stream.c b/lib/gr/stream.c
index c29e74ee2..23a349aad 100644
--- a/lib/gr/stream.c
+++ b/lib/gr/stream.c
@@ -318,7 +318,7 @@ static DWORD WINAPI grplot_thread(LPVOID parm)
   STARTUPINFOW startupInfo;
   PROCESS_INFORMATION processInformation;
 
-  StringCbPrintfW(w_cmd_line, CMD_LINE_LEN, L"cmd /c \"%ls\"", cmd);
+  StringCbPrintfW(w_cmd_line, sizeof(w_cmd_line), L"cmd /c \"%ls\"", cmd);
 
   ZeroMemory(&startupInfo, sizeof(startupInfo));
   startupInfo.cb = sizeof(startupInfo);
@@ -520,11 +520,11 @@ int gr_startlistener(void)
     {
       if (!GetEnvironmentVariableW(L"GRDIR", w_env, MAXPATHLEN))
         {
-          StringCbPrintfW(command, CMD_LINE_LEN, L"%S\\bin\\grplot.exe --listen %i", GRDIR, grplot_port);
+          StringCbPrintfW(command, sizeof(command), L"%S\\bin\\grplot.exe --listen %i", GRDIR, grplot_port);
         }
       else
         {
-          StringCbPrintfW(command, CMD_LINE_LEN, L"%s\\bin\\grplot.exe --listen %i", w_env, grplot_port);
+          StringCbPrintfW(command, sizeof(command), L"%s\\bin\\grplot.exe --listen %i", w_env, grplot_port);
         }
     }
 #else