[newlib-cygwin] Cygwin: pipe: Fix incorrect write length in raw_write()

[Takashi Yano]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=cbfaeba4f77b98219579b7569604de29e57cc9b9

commit cbfaeba4f77b98219579b7569604de29e57cc9b9
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Wed Nov 6 14:06:58 2024 +0900

    Cygwin: pipe: Fix incorrect write length in raw_write()
    
    If the write length is more than the pipe space in non-blocking
    mode, the write length is wrongly set to 65536. This causes access
    violation. This patch fixes that.
    
    Fixes: 7ed9adb356df ("Cygwin: pipe: Switch pipe mode to blocking mode by default")
    Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>

Diff:
---
 winsup/cygwin/fhandler/pipe.cc | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/winsup/cygwin/fhandler/pipe.cc b/winsup/cygwin/fhandler/pipe.cc
index a2729a119..76af6bc05 100644
--- a/winsup/cygwin/fhandler/pipe.cc
+++ b/winsup/cygwin/fhandler/pipe.cc
@@ -532,10 +532,8 @@ fhandler_pipe_fifo::raw_write (const void *ptr, size_t len)
 	}
     }
 
-  if (len <= (size_t) avail || pipe_buf_size == 0)
+  if (len <= (size_t) avail)
     chunk = len;
-  else if (is_nonblocking ())
-    chunk = len = pipe_buf_size;
   else
     chunk = avail;
 
@@ -555,7 +553,7 @@ fhandler_pipe_fifo::raw_write (const void *ptr, size_t len)
       ULONG len1;
       DWORD waitret = WAIT_OBJECT_0;
 
-      if (left > chunk)
+      if (left > chunk && !is_nonblocking ())
 	len1 = chunk;
       else
 	len1 = (ULONG) left;