From dd757cc43a710204046919da2cecf5f3b72ba33c Mon Sep 17 00:00:00 2001 From: Corinna Vinschen Date: Sun, 12 Mar 2017 12:17:43 +0100 Subject: [PATCH] Implement fhandler_dev_null::write to workaround a problem with NUL Windows NUL device returns only the lower 32 bit of the number of bytes written. Implement a fake write function to ignore the underlying NUL device. Signed-off-by: Corinna Vinschen --- winsup/cygwin/fhandler.cc | 9 +++++++++ winsup/cygwin/fhandler.h | 2 ++ 2 files changed, 11 insertions(+) diff --git a/winsup/cygwin/fhandler.cc b/winsup/cygwin/fhandler.cc index af334805a..d719b7ca2 100644 --- a/winsup/cygwin/fhandler.cc +++ b/winsup/cygwin/fhandler.cc @@ -1529,6 +1529,15 @@ fhandler_dev_null::fhandler_dev_null () : { } +ssize_t __stdcall +fhandler_dev_null::write (const void *ptr, size_t len) +{ + /* Shortcut. This also fixes a problem with the NUL device on 64 bit: + If you write > 4 GB in a single attempt, the bytes written returned + from by is numBytes & 0xffffffff. */ + return len; +} + void fhandler_base::set_no_inheritance (HANDLE &h, bool not_inheriting) { diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h index 14f7680ad..153e3847f 100644 --- a/winsup/cygwin/fhandler.h +++ b/winsup/cygwin/fhandler.h @@ -1682,6 +1682,8 @@ class fhandler_dev_null: public fhandler_base copyto (fh); return fh; } + + ssize_t __stdcall write (const void *ptr, size_t len); }; class fhandler_dev_zero: public fhandler_base