[newlib-cygwin] Cygwin: fix /proc/PID/fd return value in error case

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=e118a605e2911b04ff7e239dcbdb737ab4e96c4b

commit e118a605e2911b04ff7e239dcbdb737ab4e96c4b
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Mon Jul 22 18:36:38 2019 +0200

    Cygwin: fix /proc/PID/fd return value in error case
    
    commit 2607639992f6 "Improve error handling in /proc/[pid]/
    virtual files." changed the return value of the /proc/PID
    formatting functions to return -1 instead of 0 in the error
    case to allow a filesize of 0.
    
    The patch neglected to change this behaviour for /proc/PID/fd
    content.  This patch fixes that.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

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

diff --git a/winsup/cygwin/fhandler_process.cc b/winsup/cygwin/fhandler_process.cc
index 5ee1293..15c0a41 100644
--- a/winsup/cygwin/fhandler_process.cc
+++ b/winsup/cygwin/fhandler_process.cc
@@ -389,13 +389,13 @@ format_process_fd (void *data, char *&destbuf)
       if (fd < 0 || e == fdp || (*e != '/' && *e != '\0'))
 	{
 	  set_errno (ENOENT);
-	  return 0;
+	  return -1;
 	}
       destbuf = p ? p->fd (fd, fs) : NULL;
       if (!destbuf || !*destbuf)
 	{
 	  set_errno (ENOENT);
-	  return 0;
+	  return -1;
 	}
       if (*e == '\0')
 	*((process_fd_t *) data)->fd_type = virt_fdsymlink;