From e9c387d31a34c7bf6a67d6ae2a1e70f6cbd68cf5 Mon Sep 17 00:00:00 2001
From: Jeremy Drake <github@jdrake.com>
Date: Thu, 22 Jul 2021 11:59:16 -0700
Subject: [PATCH 26/N] Cygwin: make option for native inner link handling.

This code has been causing issues with SUBST and mapped network drives,
so add an option (defaulted to on) which can be used to disable it where
needed.  MSYS=nonativeinnerlinks
---
 winsup/cygwin/environ.cc | 1 +
 winsup/cygwin/globals.cc | 1 +
 winsup/cygwin/path.cc    | 5 +++--
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/winsup/cygwin/environ.cc b/winsup/cygwin/environ.cc
index b9600ef..06b1111 100644
--- a/winsup/cygwin/environ.cc
+++ b/winsup/cygwin/environ.cc
@@ -123,6 +123,7 @@ static struct parse_thing
   {"error_start", {func: error_start_init}, isfunc, NULL, {{0}, {0}}},
   {"export", {&export_settings}, setbool, NULL, {{false}, {true}}},
   {"glob", {func: glob_init}, isfunc, NULL, {{0}, {s: "normal"}}},
+  {"nativeinnerlinks", {&nativeinnerlinks}, setbool, NULL, {{false}, {true}}},
   {"pipe_byte", {&pipe_byte}, setbool, NULL, {{false}, {true}}},
   {"proc_retry", {func: set_proc_retry}, isfunc, NULL, {{0}, {5}}},
   {"reset_com", {&reset_com}, setbool, NULL, {{false}, {true}}},
diff --git a/winsup/cygwin/globals.cc b/winsup/cygwin/globals.cc
index 79f9476..30a2da1 100644
--- a/winsup/cygwin/globals.cc
+++ b/winsup/cygwin/globals.cc
@@ -74,6 +74,7 @@ bool wincmdln = true;
 winsym_t allow_winsymlinks = WSYM_deepcopy;
 bool disable_pcon;
 bool winjitdebug = false;
+bool nativeinnerlinks = true;
 
 /* Taken from BSD libc:
    This variable is zero until a process has created a pthread.  It is used
diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc
index b342609..688e7f7 100644
--- a/winsup/cygwin/path.cc
+++ b/winsup/cygwin/path.cc
@@ -3848,8 +3848,9 @@ restart:
 	 differ, return the final path as symlink content and set symlen
 	 to a negative value.  This forces path_conv::check to restart
 	 symlink evaluation with the new path. */
-      if ((pc_flags () & (PC_SYM_FOLLOW | PC_SYM_NOFOLLOW_REP))
-	  == PC_SYM_FOLLOW)
+      if (nativeinnerlinks
+	  && (pc_flags () & (PC_SYM_FOLLOW | PC_SYM_NOFOLLOW_REP))
+	      == PC_SYM_FOLLOW)
 	{
 	  PWCHAR fpbuf = tp.w_get ();
 	  DWORD ret;
