[newlib-cygwin/cygwin-3_5-branch] Cygwin: unlink: fix error checking order

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=ed670825e8cba3a97992558f2199cbc56c6c4a6b

commit ed670825e8cba3a97992558f2199cbc56c6c4a6b
Author:     Corinna Vinschen <corinna@vinschen.de>
AuthorDate: Tue Jan 21 17:19:24 2025 +0100
Commit:     Corinna Vinschen <corinna@vinschen.de>
CommitDate: Sat Jan 25 11:45:41 2025 +0100

    Cygwin: unlink: fix error checking order
    
    Checking EPERM only makes sense if the file exists, so
    let the EEXIST check change places with the EPERM check.
    
    Add a debug statement to the EPERM condition.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
    (cherry picked from commit b879cd1661ad2fb37f603e18f6b1860c91f445ec)

Diff:
---
 winsup/cygwin/syscalls.cc | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc
index 3b8f30e81642..83318d60570f 100644
--- a/winsup/cygwin/syscalls.cc
+++ b/winsup/cygwin/syscalls.cc
@@ -1133,17 +1133,18 @@ unlink (const char *ourname)
       set_errno (EROFS);
       goto done;
     }
-  if (!win32_name.isondisk ())
-    {
-      set_errno (EPERM);
-      goto done;
-    }
   if (!win32_name.exists ())
     {
       debug_printf ("unlinking a nonexistent file");
       set_errno (ENOENT);
       goto done;
     }
+  if (!win32_name.isondisk ())
+    {
+      debug_printf ("unlinking a virtual file");
+      set_errno (EPERM);
+      goto done;
+    }
   else if (win32_name.isdir ())
     {
       debug_printf ("unlinking a directory");