Support $! stringification of socket error codes on Windows.

The winsock error codes from WSAGetLastError() are stored by
Perl in errno, and there is some code in win32_strerror() that
would stringify them, but that code is never called when Perl
is built with the default WIN32IO_IS_STDIO setting.

This patch enables the win32_strerror() override unconditionally
and also fixes a potential memory corruption issue by using
the FORMAT_MESSAGE_IGNORE_INSERTS flag to ignore any parameter
substitution codes that may be embedded in the error message.

This now works as expected:

C:\git\perl>perl -Ilib -MPOSIX -E "$!=POSIX::EWOULDBLOCK; say $!"
A non-blocking socket operation could not be completed immediately.

diff --git a/win32/win32.c b/win32/win32.c
index 0302836..050c50c 100644 (file)
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -64,7 +64,6 @@ typedef struct {
 #define PERL_NO_GET_CONTEXT
 #include "XSUB.h"
 
-#include "Win32iop.h"
 #include <fcntl.h>
 #ifndef __GNUC__
 /* assert.h conflicts with #define of assert in perl.h */
@@ -2623,21 +2622,24 @@ win32_strerror(int e)
 #if !defined __BORLANDC__ && !defined __MINGW32__      /* compiler intolerance */
     extern int sys_nerr;
 #endif
-    DWORD source = 0;
 
     if (e < 0 || e > sys_nerr) {
         dTHX;
        if (e < 0)
            e = GetLastError();
 
-       if (FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, &source, e, 0,
-                         w32_strerror_buffer,
-                         sizeof(w32_strerror_buffer), NULL) == 0)
+       if (FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM
+                         |FORMAT_MESSAGE_IGNORE_INSERTS, NULL, e, 0,
+                         w32_strerror_buffer, sizeof(w32_strerror_buffer),
+                          NULL) == 0)
+        {
            strcpy(w32_strerror_buffer, "Unknown Error");
-
+        }
        return w32_strerror_buffer;
     }
+#undef strerror
     return strerror(e);
+#define strerror win32_strerror
 }
 
 DllExport void

diff --git a/win32/win32iop.h b/win32/win32iop.h
index b03e9a7..7507408 100644 (file)
--- a/win32/win32iop.h
+++ b/win32/win32iop.h
@@ -161,7 +161,9 @@ DllExport Sighandler_t      win32_signal(int sig, Sighandler_t subcode);
 END_EXTERN_C
 
 #undef alarm
-#define alarm                  win32_alarm
+#define alarm                          win32_alarm
+#undef strerror
+#define strerror                       win32_strerror
 
 /*
  * the following six(6) is #define in stdio.h
@@ -205,7 +207,6 @@ END_EXTERN_C
 #define ferror(f)                      win32_ferror(f)
 #define errno                          (*win32_errno())
 #define environ                                (*win32_environ())
-#define strerror                       win32_strerror
 
 /*
  * redirect to our own version
@@ -294,6 +295,10 @@ END_EXTERN_C
 #define free                   win32_free
 #endif
 
+/* XXX Why are APIs like sleep(), times() etc. inside a block
+ * XXX guarded by "#ifndef WIN32IO_IS_STDIO"?
+ */
+
 #define pipe(fd)               win32_pipe((fd), 512, O_BINARY)
 #define pause()                        win32_sleep((32767L << 16) + 32767)
 #define sleep                  win32_sleep