5 files changed, 78 insertions, 1 deletions
diff --git a/libc/src/unistd/CMakeLists.txt b/libc/src/unistd/CMakeLists.txt
index c66a3a4..78c3bf8 100644
--- a/libc/src/unistd/CMakeLists.txt
+++ b/libc/src/unistd/CMakeLists.txt
@@ -56,6 +56,13 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  faccessat
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.faccessat
+)
+
+add_entrypoint_object(
   fchdir
   ALIAS
   DEPENDS
diff --git a/libc/src/unistd/faccessat.h b/libc/src/unistd/faccessat.h
new file mode 100644
index 0000000..0dc834d
--- /dev/null
+++ b/libc/src/unistd/faccessat.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for faccessat ---------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_UNISTD_FACCESSAT_H
+#define LLVM_LIBC_SRC_UNISTD_FACCESSAT_H
+
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int faccessat(int fd, const char *path, int amode, int flag);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_UNISTD_FACCESSAT_H
diff --git a/libc/src/unistd/linux/CMakeLists.txt b/libc/src/unistd/linux/CMakeLists.txt
index 2d510f3..dff6ba2 100644
--- a/libc/src/unistd/linux/CMakeLists.txt
+++ b/libc/src/unistd/linux/CMakeLists.txt
@@ -81,6 +81,19 @@ add_entrypoint_object(
 )
 
 add_entrypoint_object(
+  faccessat
+  SRCS
+    faccessat.cpp
+  HDRS
+    ../faccessat.h
+  DEPENDS
+    libc.hdr.fcntl_macros
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
+)
+
+add_entrypoint_object(
   fchdir
   SRCS
     fchdir.cpp
diff --git a/libc/src/unistd/linux/access.cpp b/libc/src/unistd/linux/access.cpp
index 55cd6ad..f06eec5 100644
--- a/libc/src/unistd/linux/access.cpp
+++ b/libc/src/unistd/linux/access.cpp
@@ -23,7 +23,7 @@ LLVM_LIBC_FUNCTION(int, access, (const char *path, int mode)) {
   int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_access, path, mode);
 #elif defined(SYS_faccessat)
   int ret =
-      LIBC_NAMESPACE::syscall_impl<int>(SYS_faccessat, AT_FDCWD, path, mode, 0);
+      LIBC_NAMESPACE::syscall_impl<int>(SYS_faccessat, AT_FDCWD, path, mode);
 #else
 #error "access and faccessat syscalls not available."
 #endif
diff --git a/libc/src/unistd/linux/faccessat.cpp b/libc/src/unistd/linux/faccessat.cpp
new file mode 100644
index 0000000..7a2a29c
--- /dev/null
+++ b/libc/src/unistd/linux/faccessat.cpp
@@ -0,0 +1,37 @@
+//===-- Linux implementation of faccessat ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/unistd/faccessat.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+
+#include "hdr/fcntl_macros.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, faccessat,
+                   (int fd, const char *path, int amode, int flag)) {
+#ifdef SYS_faccessat2
+  int ret =
+      LIBC_NAMESPACE::syscall_impl<int>(SYS_faccessat2, fd, path, amode, flag);
+#else
+#error "faccessat2 syscall is not available."
+#endif
+
+  if (ret < 0) {
+    libc_errno = -ret;
+    return -1;
+  }
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL