wine-staging/patches/ntdll-avoid-fstatat/0001-ntdll-Avoid-fstatat.patch

From 06a8dec23dc20dae5ffe9288b7b85301b8118c0f Mon Sep 17 00:00:00 2001
From: Zebediah Figura <z.figura12@gmail.com>
Date: Sat, 28 Mar 2020 13:17:25 -0500
Subject: [PATCH] ntdll: Avoid fstatat().

---
 dlls/ntdll/directory.c  |  3 +--
 dlls/ntdll/file.c       | 20 ++++++++++++++++++--
 dlls/ntdll/ntdll_misc.h |  1 +
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/dlls/ntdll/directory.c b/dlls/ntdll/directory.c
index 993a661015..a37b287a5a 100644
--- a/dlls/ntdll/directory.c
+++ b/dlls/ntdll/directory.c
@@ -219,14 +219,13 @@ static const BOOL is_case_sensitive = FALSE;
 
 static struct file_identity windir;
 
-static RTL_CRITICAL_SECTION dir_section;
 static RTL_CRITICAL_SECTION_DEBUG critsect_debug =
 {
     0, 0, &dir_section,
     { &critsect_debug.ProcessLocksList, &critsect_debug.ProcessLocksList },
       0, 0, { (DWORD_PTR)(__FILE__ ": dir_section") }
 };
-static RTL_CRITICAL_SECTION dir_section = { &critsect_debug, -1, 0, 0, 0, 0 };
+RTL_CRITICAL_SECTION dir_section = { &critsect_debug, -1, 0, 0, 0, 0 };
 
 
 /* check if a given Unicode char is OK in a DOS short name */
diff --git a/dlls/ntdll/file.c b/dlls/ntdll/file.c
index bd27d5a434..5173c203a2 100644
--- a/dlls/ntdll/file.c
+++ b/dlls/ntdll/file.c
@@ -139,8 +139,24 @@ static inline ULONG get_file_attributes( const struct stat *st )
 static BOOL fd_is_mount_point( int fd, const struct stat *st )
 {
     struct stat parent;
-    return S_ISDIR( st->st_mode ) && !fstatat( fd, "..", &parent, 0 )
-            && (parent.st_dev != st->st_dev || parent.st_ino == st->st_ino);
+    BOOL ret = FALSE;
+    int cwd;
+
+    if (!S_ISDIR( st->st_mode )) return FALSE;
+    RtlEnterCriticalSection( &dir_section );
+    if ((cwd = open(".", O_RDONLY) == -1))
+    {
+        RtlLeaveCriticalSection( &dir_section );
+        return FALSE;
+    }
+    if (!fchdir( fd ))
+    {
+        ret = !stat( "..", &parent ) && (parent.st_dev != st->st_dev || parent.st_ino == st->st_ino);
+        if (fchdir( cwd ) == -1) chdir( "/" );
+    }
+    close( cwd );
+    RtlLeaveCriticalSection( &dir_section );
+    return ret;
 }
 
 /* get the stat info and file attributes for a file (by file descriptor) */
diff --git a/dlls/ntdll/ntdll_misc.h b/dlls/ntdll/ntdll_misc.h
index 20feabf56b..2d98e5eab6 100644
--- a/dlls/ntdll/ntdll_misc.h
+++ b/dlls/ntdll/ntdll_misc.h
@@ -169,6 +169,7 @@ extern unsigned int DIR_get_drives_info( struct drive_info info[MAX_DOS_DRIVES]
 extern NTSTATUS file_id_to_unix_file_name( const OBJECT_ATTRIBUTES *attr, ANSI_STRING *unix_name_ret ) DECLSPEC_HIDDEN;
 extern NTSTATUS nt_to_unix_file_name_attr( const OBJECT_ATTRIBUTES *attr, ANSI_STRING *unix_name_ret,
                                            UINT disposition ) DECLSPEC_HIDDEN;
+extern RTL_CRITICAL_SECTION dir_section DECLSPEC_HIDDEN;
 
 /* virtual memory */
 extern NTSTATUS virtual_alloc_aligned( PVOID *ret, unsigned short zero_bits_64, SIZE_T *size_ptr,
-- 
2.25.2