[PATCH] FAST_CWD: adjust the initial search scope

[Johannes Schindelin]

A *very* recent Windows build adds more code to the preamble of
RtlGetCurrentDirectory_U() so that the previous heuristic failed to find
the call to the locking routine.

This only affects the 64-bit version of ntdll, where the 0xe8 byte is
now found at offset 40, not the 32-bit version. However, let's just
double the area we search for said byte for good measure.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
Published-As: https://github.com/dscho/msys2-runtime/releases/tag/fast-cwd-v1
Fetch-It-Via: git fetch https://github.com/dscho/msys2-runtime fast-cwd-v1

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

diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc
index c3b304ab5..ee7636dbf 100644
--- a/winsup/cygwin/path.cc
+++ b/winsup/cygwin/path.cc
@@ -4034,7 +4034,7 @@ find_fast_cwd_pointer ()
   if (!get_dir || !ent_crit)
     return NULL;
   /* Search first relative call instruction in RtlGetCurrentDirectory_U. */
-  const uint8_t *rcall = (const uint8_t *) memchr (get_dir, 0xe8, 40);
+  const uint8_t *rcall = (const uint8_t *) memchr (get_dir, 0xe8, 80);
   if (!rcall)
     return NULL;
   /* Fetch offset from instruction and compute address of called function.
@@ -4133,7 +4133,7 @@ find_fast_cwd_pointer ()
   if (!get_dir || !ent_crit)
     return NULL;
   /* Search first relative call instruction in RtlGetCurrentDirectory_U. */
-  const uint8_t *rcall = (const uint8_t *) memchr (get_dir, 0xe8, 32);
+  const uint8_t *rcall = (const uint8_t *) memchr (get_dir, 0xe8, 64);
   if (!rcall)
     return NULL;
   /* Fetch offset from instruction and compute address of called function.

base-commit: e0477b4a0ba2b842d4f81350f7fa9a03b1f3d27b
-- 
2.11.0.310.g4ee6bc8b50