crt: Fix non-ISO (v)snwprintf() functions when __USE_MINGW_ANSI_STDIO=0

ISO C does not define (v)snwprintf() function. But ISO C11 in optional
Appendix K defines (v)snwprintf_s() function which has same behavior as
non-wide ISO C11 Appendix K (v)snprintf_s() function (which is secure
variant of (v)snprintf()).

Function (v)snwprintf() is not provided by any MS CRT library and neither
by any MS header file.

mingw32 runtime and mingw-w64 runtime since beginning provide function
named (v)snwprintf (without leading underscore) and define it under symbol
name __mingw_(v)snwprintf. This function differs from ISO C (v)swprintf()
just in return value. ISO C (v)swprintf() when buffer is too small returns
negative value but this (v)snwprintf() returns size of buffer in wide
characters, similarly to non-wide ISO C (v)snprintf() function, and also
similarly to ISO C11 Annex K (v)snwprintf_s(). This non-ISO (v)snwprintf()
and both ISO C (v)snwprintf_s() and (v)snprintf() always fill trailing nul
character.

But when __USE_MINGW_ANSI_STDIO=0 the (v)snwprintf() is redirected to
__ms_(v)snwprintf() function, which is just wrapper around msvcrt
_vsnwprintf() function. And msvcrt _vsnwprintf() function does not fill
trailing nul character and does not return required buffer size when output
buffer is too small.

So fix __ms_(v)snwprintf() functions to properly fill trailing nul
character and return required size of bufer, like ISO C vsnprintf().

Also adjust header files and remove wrong symbol aliases for (v)snwprintf
symbols from def files.

This will make API of (v)snwprintf() function compatible for both
__USE_MINGW_ANSI_STDIO=0 and __USE_MINGW_ANSI_STDIO=1 modes and also to
mimics API of ISO C (v)snwprintf_s() function.

Signed-off-by: Martin Storsjö <martin@martin.st>

mingw-w64-crt/Makefile.am

@@ -172,9 +172,11 @@ src_msvcrt_common=\
   stdio/acrt_iob_func.c \
   stdio/strtof.c \
   stdio/snprintf_alias.c \
+  stdio/snwprintf_alias.c \
   stdio/swprintf.c \
   stdio/swprintf_alias.c \
   stdio/vsnprintf_alias.c \
+  stdio/vsnwprintf_alias.c \
   stdio/vswprintf.c \
   stdio/vswprintf_alias.c \
   math/cbrt.c math/cbrtf.c \

mingw-w64-crt/lib-common/msvcrt.def.in

@@ -1926,8 +1926,3 @@ F_I386(_libm_sse2_tan_precise)
 #define USE_WCSTOK_S_FOR_WCSTOK
 #endif
 #include "crt-aliases.def.in"
-
-; This is list of additional symbol aliases not available in any CRT library
-; FIXME: check if these really are needed
-snwprintf == _snwprintf
-vsnwprintf == _vsnwprintf

mingw-w64-crt/lib32/msvcr120.def.in

@@ -2233,8 +2233,6 @@ vfwscanf
 vfwscanf_s
 vprintf
 vprintf_s
-snwprintf == _snwprintf
-vsnwprintf == _vsnwprintf
 vscanf
 vscanf_s
 vsprintf

mingw-w64-crt/lib32/msvcr120d.def.in

@@ -2300,8 +2300,6 @@ vfwscanf
 vfwscanf_s
 vprintf
 vprintf_s
-snwprintf == _snwprintf
-vsnwprintf == _vsnwprintf
 vscanf
 vscanf_s
 vsprintf

mingw-w64-crt/lib64/msvcr120.def.in

@@ -1592,8 +1592,6 @@ _vsnprintf_c_l
 _vsnprintf_l
 _vsnprintf_s
 _vsnprintf_s_l
-snwprintf == _snwprintf
-vsnwprintf == _vsnwprintf
 _vsnwprintf
 _vsnwprintf_l
 _vsnwprintf_s

mingw-w64-crt/lib64/msvcr120d.def.in

@@ -1651,8 +1651,6 @@ _vsnprintf_c_l
 _vsnprintf_l
 _vsnprintf_s
 _vsnprintf_s_l
-snwprintf == _snwprintf
-vsnwprintf == _vsnwprintf
 _vsnwprintf
 _vsnwprintf_l
 _vsnwprintf_s

mingw-w64-crt/stdio/snwprintf.c

@@ -12,7 +12,7 @@ int __cdecl __ms_snwprintf(wchar_t *buffer, size_t n, const wchar_t *format, ...
     va_list argptr;
           
     va_start(argptr, format);
-    retval = _vsnwprintf(buffer, n, format, argptr);
+    retval = __ms_vsnwprintf(buffer, n, format, argptr);
     va_end(argptr);
     return retval;
 }

mingw-w64-crt/stdio/snwprintf_alias.c

@@ -0,0 +1,26 @@
+/**
+ * This file has no copyright assigned and is placed in the Public Domain.
+ * This file is part of the mingw-w64 runtime package.
+ * No warranty is given; refer to the file DISCLAIMER.PD within this package.
+ */
+
+#include <stdarg.h>
+#include <stddef.h>
+
+/* Intentionally not including stdio.h, as it unconditionally defines the
+ * swprintf inline, and it can't be renamed with "#define snwprintf othername"
+ * either, as stdio.h contains "#undef snwprintf". */
+
+int __cdecl __ms_vsnwprintf(wchar_t *buffer, size_t n, const wchar_t *format, va_list arg);
+
+int __cdecl snwprintf(wchar_t *buffer, size_t n, const wchar_t *format, ...);
+int __cdecl snwprintf(wchar_t *buffer, size_t n, const wchar_t *format, ...)
+{
+  int retval;
+  va_list argptr;
+
+  va_start(argptr, format);
+  retval = __ms_vsnwprintf(buffer, n, format, argptr);
+  va_end(argptr);
+  return retval;
+}

mingw-w64-crt/stdio/vsnwprintf.c

@@ -12,5 +12,23 @@ int  __cdecl __ms_vsnwprintf(wchar_t *buffer,  size_t n, const wchar_t * format,
 
 int  __cdecl __ms_vsnwprintf(wchar_t *buffer,  size_t n, const wchar_t * format, va_list argptr)
 {
-    return _vsnwprintf(buffer, n, format, argptr);
+    int retval;
+
+    /* _vsnwprintf() does not work with zero length buffer
+     * so count number of characters by _vscwprintf() call */
+    if (n == 0)
+        return _vscwprintf(format, argptr);
+
+    retval = _vsnwprintf(buffer, n, format, argptr);
+
+    /* _vsnwprintf() does not fill trailing null character if there is not place for it */
+    if (retval < 0 || (size_t)retval == n)
+        buffer[n-1] = '\0';
+
+    /* _vsnwprintf() returns negative number if buffer is too small
+     * so count number of characters by _vscwprintf() call */
+    if (retval < 0)
+        retval = _vscwprintf(format, argptr);
+
+    return retval;
 }

mingw-w64-crt/stdio/vsnwprintf_alias.c

@@ -0,0 +1,20 @@
+/**
+ * This file has no copyright assigned and is placed in the Public Domain.
+ * This file is part of the mingw-w64 runtime package.
+ * No warranty is given; refer to the file DISCLAIMER.PD within this package.
+ */
+
+#include <stdarg.h>
+#include <stddef.h>
+
+/* Intentionally not including stdio.h, as it unconditionally defines the
+ * vswprintf inline, and it can't be renamed with "#define vsnwprintf othername"
+ * either, as stdio.h contains "#undef vsnwprintf". */
+
+int __cdecl __ms_vsnwprintf(wchar_t *buffer, size_t n, const wchar_t *format, va_list argptr);
+
+int __cdecl vsnwprintf(wchar_t *buffer, size_t n, const wchar_t *format, va_list argptr);
+int __cdecl vsnwprintf(wchar_t *buffer, size_t n, const wchar_t *format, va_list argptr)
+{
+  return __ms_vsnwprintf(buffer, n, format, argptr);
+}

mingw-w64-headers/crt/stdio.h

@@ -1235,7 +1235,7 @@ int vsnwprintf (wchar_t *__stream, size_t __n, const wchar_t *__format, __builti
   }
 
   __mingw_ovr
-  int snwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, ...)
+  int __cdecl snwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, ...)
   {
     __builtin_va_list __ap;
     int __ret;
@@ -1247,8 +1247,7 @@ int vsnwprintf (wchar_t *__stream, size_t __n, const wchar_t *__format, __builti
   __mingw_ovr
   int __cdecl vsnwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, va_list arg)
   {
-    int __ret = __stdio_common_vswprintf(_CRT_INTERNAL_LOCAL_PRINTF_OPTIONS, s, n, format, NULL, arg);
-    return __ret < 0 ? -1 : __ret;
+    return __stdio_common_vswprintf(_CRT_INTERNAL_LOCAL_PRINTF_OPTIONS | _CRT_INTERNAL_PRINTF_STANDARD_SNPRINTF_BEHAVIOR, s, n, format, NULL, arg);
   }
 #endif
 
@@ -1287,21 +1286,8 @@ int vsnwprintf (wchar_t *__stream, size_t __n, const wchar_t *__format, __builti
 #if __USE_MINGW_ANSI_STDIO == 0
   int __cdecl __ms_snwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, ...);
   int __cdecl __ms_vsnwprintf (wchar_t * __restrict__ , size_t, const wchar_t * __restrict__ , va_list);
-  __mingw_ovr
-  int snwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, ...)
-  {
-    int r;
-    va_list argp;
-    __builtin_va_start (argp, format);
-    r = _vsnwprintf (s, n, format, argp);
-    __builtin_va_end (argp);
-    return r;
-  }
-  __mingw_ovr
-  int __cdecl vsnwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, va_list arg)
-  {
-    return _vsnwprintf(s,n,format,arg);
-  }
+  int __cdecl snwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, ...) __MINGW_ASM_CALL(__ms_snwprintf);
+  int __cdecl vsnwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, va_list arg) __MINGW_ASM_CALL(__ms_vsnwprintf);
 #endif
 
 #endif /* ! __NO_ISOCEXT */

mingw-w64-headers/crt/wchar.h

@@ -759,12 +759,12 @@ __MINGW_ASM_CALL(__mingw_vsnwprintf);
     __builtin_va_start(__ap, format);
     __ret = __stdio_common_vswprintf(_CRT_INTERNAL_LOCAL_PRINTF_OPTIONS | _CRT_INTERNAL_PRINTF_STANDARD_SNPRINTF_BEHAVIOR, s, n, format, NULL, __ap);
     __builtin_va_end(__ap);
-    return __ret;
+    return __ret < 0 ? -1 : __ret;
   }
   __mingw_ovr
   int __cdecl vsnwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, va_list arg)
   {
-    int __ret = __stdio_common_vswprintf(_CRT_INTERNAL_LOCAL_PRINTF_OPTIONS, s, n, format, NULL, arg);
+    int __ret = __stdio_common_vswprintf(_CRT_INTERNAL_LOCAL_PRINTF_OPTIONS | _CRT_INTERNAL_PRINTF_STANDARD_SNPRINTF_BEHAVIOR, s, n, format, NULL, arg);
     return __ret < 0 ? -1 : __ret;
   }
 #endif
@@ -786,21 +786,8 @@ __MINGW_ASM_CALL(__mingw_vsnwprintf);
 # undef vsnwprintf
   int __cdecl __ms_snwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, ...);
   int __cdecl __ms_vsnwprintf (wchar_t * __restrict__ , size_t, const wchar_t * __restrict__ , va_list);
-  __mingw_ovr
-  int snwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, ...)
-  {
-    int r;
-    va_list argp;
-    __builtin_va_start (argp, format);
-    r = _vsnwprintf (s, n, format, argp);
-    __builtin_va_end (argp);
-    return r;
-  }
-  __mingw_ovr
-  int __cdecl vsnwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, va_list arg)
-  {
-    return _vsnwprintf(s,n,format,arg);
-  }
+  int __cdecl snwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, ...) __MINGW_ASM_CALL(__ms_snwprintf);
+  int __cdecl vsnwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t * __restrict__ format, va_list arg) __MINGW_ASM_CALL(__ms_vsnwprintf);
 #pragma pop_macro ("vsnwprintf")
 #pragma pop_macro ("snwprintf")
 #endif