[libc] remove #include <fcntl.h> and add proxy or type (#113836)

Author: Job Henandez Lara

libc/hdr/CMakeLists.txt

@@ -51,10 +51,13 @@ add_proxy_header_library(
     libc.include.llvm-libc-macros.generic_error_number_macros
 )
 
+add_header_library(fcntl_overlay HDRS fcntl_overlay.h)
 add_proxy_header_library(
   fcntl_macros
   HDRS
     fcntl_macros.h
+  DEPENDS
+    .fcntl_overlay
   FULL_BUILD_DEPENDS
     libc.include.llvm-libc-macros.fcntl_macros
     libc.include.fcntl

libc/hdr/fcntl_macros.h

@@ -15,7 +15,7 @@
 
 #else // Overlay mode
 
-#include <fcntl.h>
+#include "hdr/fcntl_overlay.h"
 
 #endif // LLVM_LIBC_FULL_BUILD
 

libc/hdr/fcntl_overlay.h

@@ -0,0 +1,37 @@
+//===-- Including fcntl.h in overlay mode ---------------------------------===//
+//
+// 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_HDR_FCNTL_OVERLAY_H
+#define LLVM_LIBC_HDR_FCNTL_OVERLAY_H
+
+#ifdef LIBC_FULL_BUILD
+#error "This header should only be included in overlay mode"
+#endif
+
+// Overlay mode
+
+// glibc <fcntl.h> header might provide extern inline definitions for few
+// functions, causing external alias errors.  They are guarded by
+// `__USE_FORTIFY_LEVEL`, which will be temporarily disabled
+// with `_FORTIFY_SOURCE`.
+
+#ifdef __USE_FORTIFY_LEVEL
+#define LIBC_OLD_USE_FORTIFY_LEVEL __USE_FORTIFY_LEVEL
+#undef __USE_FORTIFY_LEVEL
+#define __USE_FORTIFY_LEVEL 0
+#endif
+
+#include <fcntl.h>
+
+#ifdef LIBC_OLD_USE_FORTIFY_LEVEL
+#undef __USE_FORTIFY_LEVEL
+#define __USE_FORTIFY_LEVEL LIBC_OLD_USE_FORTIFY_LEVEL
+#undef LIBC_OLD_USE_FORTIFY_LEVEL
+#endif
+
+#endif // LLVM_LIBC_HDR_FCNTL_OVERLAY_H

libc/hdr/types/CMakeLists.txt

@@ -46,6 +46,17 @@ add_proxy_header_library(
     libc.include.llvm-libc-types.struct_timespec
 )
 
+add_proxy_header_library(
+  mode_t
+  HDRS
+    mode_t.h
+  DEPENDS
+    ../fcntl_overlay
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.mode_t
+    libc.include.fcntl
+)
+
 add_proxy_header_library(
   fenv_t
   HDRS

libc/hdr/types/mode_t.h

@@ -0,0 +1,22 @@
+//===-- Definition of macros from mode_t.h --------------------------------===//
+//
+// 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_HDR_MODE_T_H
+#define LLVM_LIBC_HDR_MODE_T_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/mode_t.h"
+
+#else // Overlay mode
+
+#include "hdr/fcntl_overlay.h"
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_MODE_T_H

libc/src/__support/File/linux/CMakeLists.txt

@@ -7,7 +7,7 @@ add_object_library(
     file.h
     lseekImpl.h
   DEPENDS
-    libc.include.fcntl
+    libc.hdr.fcntl_macros
     libc.include.sys_syscall
     libc.include.sys_stat
     libc.src.__support.CPP.new
@@ -55,7 +55,7 @@ add_object_library(
   SRCS
     dir.cpp
   DEPENDS
-    libc.include.fcntl
+    libc.hdr.fcntl_macros
     libc.include.sys_syscall
     libc.src.__support.OSUtil.osutil
     libc.src.__support.error_or

libc/src/__support/File/linux/dir.cpp

@@ -12,7 +12,7 @@
 #include "src/__support/error_or.h"
 #include "src/__support/macros/config.h"
 
-#include <fcntl.h>       // For open flags
+#include "hdr/fcntl_macros.h" // For open flags
 #include <sys/syscall.h> // For syscall numbers
 
 namespace LIBC_NAMESPACE_DECL {

libc/src/__support/File/linux/file.cpp

@@ -18,7 +18,7 @@
 #include "src/__support/macros/config.h"
 #include "src/errno/libc_errno.h" // For error macros
 
-#include <fcntl.h>       // For mode_t and other flags to the open syscall
+#include "hdr/fcntl_macros.h" // For mode_t and other flags to the open syscall
 #include <sys/stat.h>    // For S_IS*, S_IF*, and S_IR* flags.
 #include <sys/syscall.h> // For syscall numbers
 

libc/src/__support/threads/linux/CMakeLists.txt

@@ -79,7 +79,7 @@ add_object_library(
     .futex_utils
     libc.config.app_h
     libc.include.sys_syscall
-    libc.include.fcntl
+    libc.hdr.fcntl_macros  
     libc.src.errno.errno
     libc.src.__support.CPP.atomic
     libc.src.__support.CPP.stringstream

libc/src/__support/threads/linux/thread.cpp

@@ -22,7 +22,7 @@
 #include <arm_acle.h>
 #endif
 
-#include <fcntl.h>
+#include "hdr/fcntl_macros.h"
 #include <linux/param.h> // For EXEC_PAGESIZE.
 #include <linux/prctl.h> // For PR_SET_NAME
 #include <linux/sched.h> // For CLONE_* flags.