[perl #125347] allow truncate to work on large files on Win32

truncate($filename, $size) was using a simple PerlIO_open() to open
the file, which on Win32 defaults to a text mode open.

Unfortunately, on a text mode open(), MSVCRT attempts to seek to the
end of file using only 32-bit offsets, which fails.

For good measure, add in O_LARGEFILE if it's available, which may
prevent similar issues on other platforms.

Also, remove the erroneous SETERRNO() added by 375ed12a to the open
failure branch, PerlLIO_open() should already set errno on failure, so
we get sane error messages when the open fails.

1 files changed, 14 insertions, 2 deletions

diff --git a/pp_sys.c b/pp_sys.c
index 7c20f529d1..38537f3280 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -2304,10 +2304,22 @@ PP(pp_truncate)
 	        result = 0;
 #else
 	    {
-		const int tmpfd = PerlLIO_open(name, O_RDWR);
+                int mode = O_RDWR;
+                int tmpfd;
+
+#if defined(USE_64_BIT_RAWIO) && defined(O_LARGEFILE)
+                mode |= O_LARGEFILE;	/* Transparently largefiley. */
+#endif
+#ifdef O_BINARY
+                /* On open(), the Win32 CRT tries to seek around text
+                 * files using 32-bit offsets, which causes the open()
+                 * to fail on large files, so open in binary mode.
+                 */
+                mode |= O_BINARY;
+#endif
+                tmpfd = PerlLIO_open(name, mode);
 
 		if (tmpfd < 0) {
-                    SETERRNO(EBADF,RMS_IFI);
 		    result = 0;
 		} else {
 		    if (my_chsize(tmpfd, len) < 0)