fixup! Instead of creating Cygwin symlinks, use deep copy by default

factor out duplicated code to mangle a relative symlink target.

Author: jeremyd2019

winsup/cygwin/path.cc

@@ -1879,6 +1879,31 @@ symlink (const char *oldpath, const char *newpath)
   return -1;
 }
 
+static bool
+mangle_symlink_target (const char *oldpath, const path_conv &win32_newpath,
+		       path_conv &win32_oldpath)
+{
+  /* The symlink target is relative to the directory in which the
+     symlink gets created, not relative to the cwd.  Therefore we
+     have to mangle the path quite a bit before calling path_conv.*/
+  if (isabspath (oldpath))
+    {
+      win32_oldpath.check (oldpath, PC_SYM_NOFOLLOW, stat_suffixes);
+      return true;
+    }
+  else
+    {
+      tmp_pathbuf tp;
+      size_t len = strrchr (win32_newpath.get_posix (), '/')
+	    - win32_newpath.get_posix () + 1;
+      char *absoldpath = tp.t_get ();
+      stpcpy (stpncpy (absoldpath, win32_newpath.get_posix (), len),
+	      oldpath);
+      win32_oldpath.check (absoldpath, PC_SYM_NOFOLLOW, stat_suffixes);
+      return false;
+    }
+}
+
 static int
 symlink_nfs (const char *oldpath, path_conv &win32_newpath)
 {
@@ -1939,23 +1964,10 @@ symlink_native (const char *oldpath, path_conv &win32_newpath)
   UNICODE_STRING final_oldpath_buf;
   DWORD flags;
 
-  if (isabspath (oldpath))
-    {
-      win32_oldpath.check (oldpath, PC_SYM_NOFOLLOW, stat_suffixes);
-      final_oldpath = win32_oldpath.get_nt_native_path ();
-    }
+  if (mangle_symlink_target (oldpath, win32_newpath, win32_oldpath))
+    final_oldpath = win32_oldpath.get_nt_native_path ();
   else
     {
-      /* The symlink target is relative to the directory in which
-	 the symlink gets created, not relative to the cwd.  Therefore
-	 we have to mangle the path quite a bit before calling path_conv. */
-      ssize_t len = strrchr (win32_newpath.get_posix (), '/')
-		    - win32_newpath.get_posix () + 1;
-      char *absoldpath = tp.t_get ();
-      stpcpy (stpncpy (absoldpath, win32_newpath.get_posix (), len),
-	      oldpath);
-      win32_oldpath.check (absoldpath, PC_SYM_NOFOLLOW, stat_suffixes);
-
       /* Try hard to keep Windows symlink path relative. */
 
       /* 1. Find common path prefix.  Skip leading \\?\, but take pre-increment
@@ -2260,21 +2272,7 @@ symlink_worker (const char *oldpath, path_conv &win32_newpath, bool isdevice)
 	      /* The symlink target is relative to the directory in which the
 		 symlink gets created, not relative to the cwd.  Therefore we
 		 have to mangle the path quite a bit before calling path_conv.*/
-	      if (isabspath (oldpath))
-		win32_oldpath.check (oldpath,
-				     PC_SYM_NOFOLLOW,
-				     stat_suffixes);
-	      else
-		{
-		  len = strrchr (win32_newpath.get_posix (), '/')
-			- win32_newpath.get_posix () + 1;
-		  char *absoldpath = tp.t_get ();
-		  stpcpy (stpncpy (absoldpath, win32_newpath.get_posix (),
-				   len),
-			  oldpath);
-		  win32_oldpath.check (absoldpath, PC_SYM_NOFOLLOW,
-				       stat_suffixes);
-		}
+	      mangle_symlink_target (oldpath, win32_newpath, win32_oldpath);
 	      if (SUCCEEDED (SHGetDesktopFolder (&psl)))
 		{
 		  WCHAR wc_path[win32_oldpath.get_wide_win32_path_len () + 1];
@@ -2378,29 +2376,15 @@ symlink_worker (const char *oldpath, path_conv &win32_newpath, bool isdevice)
 		  * sizeof (WCHAR);
 	  cp += *plen;
 	}
-      else /* wsym_type == WSYM_sysfile */
+      else
 	{
 	  if (wsym_type == WSYM_deepcopy)
 	    {
 	      path_conv win32_oldpath;
 	      /* The symlink target is relative to the directory in which the
 		 symlink gets created, not relative to the cwd.  Therefore we
 		 have to mangle the path quite a bit before calling path_conv.*/
-	      if (isabspath (oldpath))
-		win32_oldpath.check (oldpath,
-				     PC_SYM_NOFOLLOW,
-				     stat_suffixes);
-	      else
-		{
-		  len = strrchr (win32_newpath.get_posix (), '/')
-			- win32_newpath.get_posix () + 1;
-		  char *absoldpath = tp.t_get ();
-		  stpcpy (stpncpy (absoldpath, win32_newpath.get_posix (),
-				   len),
-			  oldpath);
-		  win32_oldpath.check (absoldpath, PC_SYM_NOFOLLOW,
-				       stat_suffixes);
-		}
+	      mangle_symlink_target (oldpath, win32_newpath, win32_oldpath);
 	      if (win32_oldpath.error)
 		{
 		  set_errno (win32_oldpath.error);
@@ -2464,6 +2448,7 @@ symlink_worker (const char *oldpath, path_conv &win32_newpath, bool isdevice)
 		}
 	    }
 
+	  /* wsym_type == WSYM_sysfile */
 	  /* Default technique creating a symlink. */
 	  buf = tp.t_get ();
 	  cp = stpcpy (buf, SYMLINK_COOKIE);