[libc] Add POSIX close, fsync, open, read and write functions.

Siva Chandra Reddy · Siva Chandra Reddy · commit dc2b01b3f7b0 · 2022-01-27T20:32:02.000Z
They are implemented as simple syscall wrappers. The file creation macros have been put in a header file as a temporary solution until we have a cleaner approach to listing platform relevant macros. Reviewed By: abrachet Differential Revision: https://reviews.llvm.org/D118396
diff --git a/libc/config/linux/api.td b/libc/config/linux/api.td
@@ -62,6 +62,10 @@ def AssertAPI : PublicAPI<"assert.h"> {
 def CTypeAPI : PublicAPI<"ctype.h"> {
 }
 
+def FCntlAPI : PublicAPI<"fcntl.h"> {
+  let Types = ["mode_t"];
+}
+
 def IntTypesAPI : PublicAPI<"inttypes.h"> {
   let Types = ["imaxdiv_t"];
 }
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
@@ -20,6 +20,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     # errno.h entrypoints
     libc.src.errno.__errno_location
 
+    # fcntl.h entrypoints
+    libc.src.fcntl.open
+
     # string.h entrypoints
     libc.src.string.bcmp
     libc.src.string.bzero
@@ -81,6 +84,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.sys.mman.munmap
 
     # unistd.h entrypoints
+    libc.src.unistd.close
+    libc.src.unistd.fsync
+    libc.src.unistd.read
     libc.src.unistd.write
 )
 
diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
@@ -1,3 +1,4 @@
+add_subdirectory(llvm-libc-macros)
 add_subdirectory(llvm-libc-types)
 
 add_header(
@@ -14,6 +15,16 @@ add_gen_header(
     .llvm_libc_common_h
 )
 
+add_gen_header(
+  fcntl
+  DEF_FILE fcntl.h.def
+  GEN_HDR fcntl.h
+  DEPENDS
+    .llvm_libc_common_h
+    .llvm-libc-macros.fcntl_macros
+    .llvm-libc-types.mode_t
+)
+
 add_gen_header(
   fenv
   DEF_FILE fenv.h.def
diff --git a/libc/include/fcntl.h.def b/libc/include/fcntl.h.def
@@ -0,0 +1,17 @@
+//===-- C standard library header fcntl.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_FCNTL_H
+#define LLVM_LIBC_FCNTL_H
+
+#include <__llvm-libc-common.h>
+#include <llvm-libc-macros/fcntl-macros.h>
+
+%%public_api()
+
+#endif // LLVM_LIBC_FCNTL_H 
diff --git a/libc/include/llvm-libc-macros/CMakeLists.txt b/libc/include/llvm-libc-macros/CMakeLists.txt
@@ -0,0 +1,9 @@
+add_subdirectory(linux)
+
+add_header(
+  fcntl_macros
+  HDR
+    fcntl-macros.h
+  DEPENDS
+    .linux.fcntl_macros
+)
diff --git a/libc/include/llvm-libc-macros/fcntl-macros.h b/libc/include/llvm-libc-macros/fcntl-macros.h
@@ -0,0 +1,8 @@
+#ifndef __LLVM_LIBC_MACROS_FCNTL_MACROS_H
+#define __LLVM_LIBC_MACROS_FCNTL_MACROS_H
+
+#ifdef __unix__
+#include "linux/fcntl-macros.h"
+#endif
+
+#endif // __LLVM_LIBC_MACROS_FCNTL_MACROS_H
diff --git a/libc/include/llvm-libc-macros/linux/CMakeLists.txt b/libc/include/llvm-libc-macros/linux/CMakeLists.txt
@@ -0,0 +1,5 @@
+add_header(
+  fcntl_macros
+  HDR
+    fcntl-macros.h
+)
diff --git a/libc/include/llvm-libc-macros/linux/fcntl-macros.h b/libc/include/llvm-libc-macros/linux/fcntl-macros.h
@@ -0,0 +1,52 @@
+//===-- Definition of macros from fcntl.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_MACROS_LINUX_FCNTL_MACROS_H
+#define __LLVM_LIBC_MACROS_LINUX_FCNTL_MACROS_H
+
+// File creation flags
+#define O_CLOEXEC 02000000
+#define O_CREAT 00000100
+#define O_DIRECTORY 00200000
+#define O_EXCL 00000200
+#define O_NOCTTY 00000400
+#define O_NOFOLLOW 00400000
+#define O_TRUNC 00001000
+#define O_TMPFILE (020000000 | O_DIRECTORY)
+
+// File status flags
+#define O_APPEND 00002000
+#define O_DSYNC 00010000
+#define O_NONBLOCK 00004000
+#define O_SYNC 04000000 | O_DSYNC
+
+// File access mode mask
+#define O_ACCMODE 00000003
+
+// File access mode flags
+#define O_RDONLY 00000000
+#define O_RDWR 00000002
+#define O_WRONLY 00000001
+
+// File mode flags
+#define S_IRWXU 0700
+#define S_IRUSR 0400
+#define S_IWUSR 0200
+#define S_IXUSR 0100
+#define S_IRWXG 070
+#define S_IRGRP 040
+#define S_IWGRP 020
+#define S_IXGRP 010
+#define S_IRWXO 07
+#define S_IROTH 04
+#define S_IWOTH 02
+#define S_IXOTH 01
+#define S_ISUID 04000
+#define S_ISGID 02000
+
+#endif // __LLVM_LIBC_MACROS_LINUX_FCNTL_MACROS_H
diff --git a/libc/include/llvm-libc-types/CMakeLists.txt b/libc/include/llvm-libc-types/CMakeLists.txt
@@ -12,6 +12,7 @@ add_header(fenv_t HDR fenv_t.h)
 add_header(fexcept_t HDR fexcept_t.h)
 add_header(float_t HDR float_t.h)
 add_header(imaxdiv_t HDR imaxdiv_t.h)
+add_header(mode_t HDR mode_t.h)
 add_header(mtx_t HDR mtx_t.h)
 add_header(off_t HDR off_t.h)
 add_header(once_flag HDR once_flag.h)
diff --git a/libc/include/llvm-libc-types/mode_t.h b/libc/include/llvm-libc-types/mode_t.h
@@ -0,0 +1,14 @@
+//===-- Definition of mode_t type -----------------------------------------===//
+//
+// 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_TYPES_MODE_T_H
+#define __LLVM_LIBC_TYPES_MODE_T_H
+
+typedef unsigned mode_t;
+
+#endif // __LLVM_LIBC_TYPES_MODE_T_H
diff --git a/libc/spec/posix.td b/libc/spec/posix.td
@@ -17,6 +17,7 @@ def POSIX : StandardSpec<"POSIX"> {
   ConstType ConstCharPtr = ConstType<CharPtr>;
   ConstType ConstRestrictedCharPtr = ConstType<RestrictedCharPtr>;
 
+  NamedType ModeTType = NamedType<"mode_t">;
   NamedType OffTType = NamedType<"off_t">;
   NamedType SSizeTType = NamedType<"ssize_t">;
 
@@ -107,6 +108,20 @@ def POSIX : StandardSpec<"POSIX"> {
       []  // Functions
   >;
 
+  HeaderSpec FCntl = HeaderSpec<
+    "fcntl.h",
+    [], // Macros
+    [ModeTType],
+    [], // Enumerations
+    [
+      FunctionSpec<
+          "open",
+          RetValSpec<IntType>,
+          [ArgSpec<ConstCharPtr>, ArgSpec<IntType>, ArgSpec<VarArgType>]
+      >,
+    ]
+  >;
+
   HeaderSpec SysMMan = HeaderSpec<
       "sys/mman.h",
       [
@@ -202,6 +217,21 @@ def POSIX : StandardSpec<"POSIX"> {
     ],
     [], // Enumerations
     [
+        FunctionSpec<
+          "close",
+          RetValSpec<IntType>,
+          [ArgSpec<IntType>]
+        >,
+        FunctionSpec<
+          "fsync",
+          RetValSpec<IntType>,
+          [ArgSpec<IntType>]
+        >,
+        FunctionSpec<
+          "read",
+          RetValSpec<SSizeTType>,
+          [ArgSpec<IntType>, ArgSpec<VoidPtr>, ArgSpec<SizeTType>]
+        >,
         FunctionSpec<
           "write",
           RetValSpec<SSizeTType>,
@@ -280,6 +310,7 @@ def POSIX : StandardSpec<"POSIX"> {
   let Headers = [
     CType,
     Errno,
+    FCntl,
     SysMMan,
     Signal,
     UniStd,
diff --git a/libc/src/CMakeLists.txt b/libc/src/CMakeLists.txt
@@ -9,6 +9,7 @@ add_subdirectory(string)
 add_subdirectory(stdlib)
 
 if(${LIBC_TARGET_OS} STREQUAL "linux")
+  add_subdirectory(fcntl)
   add_subdirectory(sys)
   add_subdirectory(unistd)
 endif()
diff --git a/libc/src/fcntl/CMakeLists.txt b/libc/src/fcntl/CMakeLists.txt
@@ -0,0 +1,10 @@
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+endif()
+
+add_entrypoint_object(
+  open
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.open
+)
diff --git a/libc/src/fcntl/linux/CMakeLists.txt b/libc/src/fcntl/linux/CMakeLists.txt
@@ -0,0 +1,12 @@
+add_entrypoint_object(
+  open
+  SRCS
+    open.cpp
+  HDRS
+    ../open.h
+  DEPENDS
+    libc.include.errno
+    libc.include.fcntl
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.__errno_location
+)
diff --git a/libc/src/fcntl/linux/open.cpp b/libc/src/fcntl/linux/open.cpp
@@ -0,0 +1,40 @@
+//===-- Implementation of open --------------------------------------------===//
+//
+// 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/fcntl/open.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, open, (const char *path, int flags, ...)) {
+  mode_t mode_flags = 0;
+  // O_TMPFILE is a multi-bit flag so we test all bits by checking for equality
+  // with O_TMPFILE
+  if ((flags & O_CREAT) || (flags & O_TMPFILE) == O_TMPFILE) {
+    va_list varargs;
+    va_start(varargs, flags);
+    mode_flags = va_arg(varargs, mode_t);
+    va_end(varargs);
+  }
+
+  int fd = __llvm_libc::syscall(SYS_open, path, flags, mode_flags);
+  if (fd > 0)
+    return fd;
+
+  errno = -fd;
+  return -1;
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/fcntl/open.h b/libc/src/fcntl/open.h
@@ -0,0 +1,20 @@
+//===-- Implementation header of open ---------------------------*- 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_FCNTL_OPEN_H
+#define LLVM_LIBC_SRC_FCNTL_OPEN_H
+
+#include <fcntl.h>
+
+namespace __llvm_libc {
+
+int open(const char *path, int flags, ...);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_FCNTL_OPEN_H
diff --git a/libc/src/unistd/CMakeLists.txt b/libc/src/unistd/CMakeLists.txt
@@ -2,6 +2,27 @@ if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
 endif()
 
+add_entrypoint_object(
+  close
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.close
+)
+
+add_entrypoint_object(
+  fsync
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.fsync
+)
+
+add_entrypoint_object(
+  read
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.read
+)
+
 add_entrypoint_object(
   write
   ALIAS
diff --git a/libc/src/unistd/close.h b/libc/src/unistd/close.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for close -------------------------*- 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_CLOSE_H
+#define LLVM_LIBC_SRC_UNISTD_CLOSE_H
+
+namespace __llvm_libc {
+
+int close(int fd);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_UNISTD_CLOSE_H
diff --git a/libc/src/unistd/fsync.h b/libc/src/unistd/fsync.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for fsync -------------------------*- 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_FSYNC_H
+#define LLVM_LIBC_SRC_UNISTD_FSYNC_H
+
+namespace __llvm_libc {
+
+int fsync(int fd);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_UNISTD_FSYNC_H
diff --git a/libc/src/unistd/linux/CMakeLists.txt b/libc/src/unistd/linux/CMakeLists.txt
diff --git a/libc/src/unistd/linux/close.cpp b/libc/src/unistd/linux/close.cpp
diff --git a/libc/src/unistd/linux/fsync.cpp b/libc/src/unistd/linux/fsync.cpp
diff --git a/libc/src/unistd/linux/read.cpp b/libc/src/unistd/linux/read.cpp
diff --git a/libc/src/unistd/linux/write.cpp b/libc/src/unistd/linux/write.cpp
diff --git a/libc/src/unistd/read.h b/libc/src/unistd/read.h
diff --git a/libc/test/src/unistd/CMakeLists.txt b/libc/test/src/unistd/CMakeLists.txt
diff --git a/libc/test/src/unistd/read_write_test.cpp b/libc/test/src/unistd/read_write_test.cpp
diff --git a/libc/test/src/unistd/write_test.cpp b/libc/test/src/unistd/write_test.cpp

Original file line number	Diff line number	Diff line change
`@@ -62,6 +62,10 @@ def AssertAPI : PublicAPI<"assert.h"> {`
`62`	`62`	`def CTypeAPI : PublicAPI<"ctype.h"> {`
`63`	`63`	`}`
`64`	`64`
	`65`	`+def FCntlAPI : PublicAPI<"fcntl.h"> {`
	`66`	`+ let Types = ["mode_t"];`
	`67`	`+}`
	`68`	`+`
`65`	`69`	`def IntTypesAPI : PublicAPI<"inttypes.h"> {`
`66`	`70`	`let Types = ["imaxdiv_t"];`
`67`	`71`	`}`