[libc] Add the implementation of the GNU extension function fopencookie.

Reviewed By: lntue, michaelrj

Differential Revision: https://reviews.llvm.org/D124141

Author: Siva Chandra Reddy

libc/config/linux/api.td

@@ -146,7 +146,7 @@ def StringAPI : PublicAPI<"string.h"> {
 }
 
 def StdIOAPI : PublicAPI<"stdio.h"> {
-  let Types = ["size_t", "FILE"];
+  let Types = ["size_t", "FILE", "cookie_io_functions_t"];
 }
 
 def StdlibAPI : PublicAPI<"stdlib.h"> {

libc/config/linux/x86_64/entrypoints.txt

@@ -255,6 +255,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.stdio.flockfile
     libc.src.stdio.fflush
     libc.src.stdio.fopen
+    libc.src.stdio.fopencookie
     libc.src.stdio.fread
     libc.src.stdio.fread_unlocked
     libc.src.stdio.fseek

libc/include/CMakeLists.txt

@@ -125,6 +125,7 @@ add_gen_header(
   DEPENDS
     .llvm_libc_common_h
     .llvm-libc-macros.file_seek_macros
+    .llvm-libc-types.cookie_io_functions_t
     .llvm-libc-types.FILE
     .llvm-libc-types.size_t
 )

libc/include/llvm-libc-types/CMakeLists.txt

@@ -5,6 +5,7 @@ add_header(__mutex_type HDR __mutex_type.h)
 add_header(__qsortcompare_t HDR __qsortcompare_t.h)
 add_header(__sighandler_t HDR __sighandler_t.h)
 add_header(cnd_t HDR cnd_t.h)
+add_header(cookie_io_functions_t HDR cookie_io_functions_t.h DEPENDS .off64_t)
 add_header(double_t HDR double_t.h)
 add_header(div_t HDR div_t.h)
 add_header(ldiv_t HDR ldiv_t.h)
@@ -17,6 +18,7 @@ add_header(imaxdiv_t HDR imaxdiv_t.h)
 add_header(mode_t HDR mode_t.h)
 add_header(mtx_t HDR mtx_t.h DEPENDS .__futex_word .__mutex_type)
 add_header(off_t HDR off_t.h)
+add_header(off64_t HDR off64_t.h)
 add_header(once_flag HDR once_flag.h DEPENDS .__futex_word)
 add_header(pthread_attr_t HDR pthread_attr_t.h)
 add_header(pthread_mutexattr_t HDR pthread_mutexattr_t.h)

libc/include/llvm-libc-types/cookie_io_functions_t.h

@@ -0,0 +1,28 @@
+//===-- Definition of type cookie_io_functions_t --------------------------===//
+//
+// 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_COOKIE_IO_FUNCTIONS_T_H
+#define __LLVM_LIBC_TYPES_COOKIE_IO_FUNCTIONS_T_H
+
+#include <llvm-libc-types/off64_t.h>
+#include <llvm-libc-types/size_t.h>
+#include <llvm-libc-types/ssize_t.h>
+
+typedef ssize_t cookie_read_function_t(void *, char *, size_t);
+typedef ssize_t cookie_write_function_t(void *, const char *, size_t);
+typedef int cookie_seek_function_t(void *, off64_t *, int);
+typedef int cookie_close_function_t(void *);
+
+typedef struct {
+  cookie_read_function_t *read;
+  cookie_write_function_t *write;
+  cookie_seek_function_t *seek;
+  cookie_close_function_t *close;
+} cookie_io_functions_t;
+
+#endif // __LLVM_LIBC_TYPES_COOKIE_IO_FUNCTIONS_T_H

libc/include/llvm-libc-types/off64_t.h

@@ -0,0 +1,14 @@
+//===-- Definition of off64_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_OFF64_T_H__
+#define __LLVM_LIBC_TYPES_OFF64_T_H__
+
+typedef __INT64_TYPE__ off64_t;
+
+#endif // __LLVM_LIBC_TYPES_OFF64_T_H__

libc/spec/gnu_ext.td

@@ -1,4 +1,5 @@
 def GnuExtensions : StandardSpec<"GNUExtensions"> {
+  NamedType CookieIOFunctionsT = NamedType<"cookie_io_functions_t">;
   HeaderSpec CType = HeaderSpec<
     "ctype.h",
     [], // Macros
@@ -68,9 +69,14 @@ def GnuExtensions : StandardSpec<"GNUExtensions"> {
   HeaderSpec StdIO = HeaderSpec<
       "stdio.h",
       [], // Macros
-      [], // Types
+      [CookieIOFunctionsT], // Types
       [], // Enumerations
       [
+          FunctionSpec<
+              "fopencookie",
+              RetValSpec<FILEPtr>,
+              [ArgSpec<VoidPtr>, ArgSpec<ConstCharPtr>, ArgSpec<CookieIOFunctionsT>]
+          >,
           FunctionSpec<
               "fread_unlocked",
               RetValSpec<SizeTType>,
@@ -88,7 +94,7 @@ def GnuExtensions : StandardSpec<"GNUExtensions"> {
                ArgSpec<FILERestrictedPtr>]
           >,
       ]
-   >;
+  >;
 
   let Headers = [
     CType,

libc/spec/spec.td

@@ -110,7 +110,6 @@ def FILERestrictedPtr : RestrictedPtrType<FILE>;
 //added because __assert_fail needs it.
 def UnsignedType : NamedType<"unsigned">;
 
-
 class Macro<string name> {
   string Name = name;
 }

libc/src/stdio/CMakeLists.txt

@@ -119,3 +119,14 @@ add_entrypoint_object(
     libc.src.__support.File.file
     libc.src.__support.File.platform_file
 )
+
+add_entrypoint_object(
+  fopencookie
+  SRCS
+    fopencookie.cpp
+  HDRS
+    fopencookie.h
+  DEPENDS
+    libc.include.stdio
+    libc.src.__support.File.file
+)

libc/src/stdio/fopencookie.cpp

@@ -0,0 +1,83 @@
+//===-- Implementation of fopencookie -------------------------------------===//
+//
+// 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/stdio/fopencookie.h"
+#include "src/__support/File/file.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+namespace __llvm_libc {
+
+namespace {
+
+class CookieFile : public __llvm_libc::File {
+public:
+  void *cookie;
+  cookie_io_functions_t ops;
+};
+
+size_t write_func(File *f, const void *data, size_t size) {
+  auto cookie_file = reinterpret_cast<CookieFile *>(f);
+  if (cookie_file->ops.write == nullptr)
+    return 0;
+  return cookie_file->ops.write(cookie_file->cookie,
+                                reinterpret_cast<const char *>(data), size);
+}
+
+size_t read_func(File *f, void *data, size_t size) {
+  auto cookie_file = reinterpret_cast<CookieFile *>(f);
+  if (cookie_file->ops.read == nullptr)
+    return 0;
+  return cookie_file->ops.read(cookie_file->cookie,
+                               reinterpret_cast<char *>(data), size);
+}
+
+int seek_func(File *f, long offset, int whence) {
+  auto cookie_file = reinterpret_cast<CookieFile *>(f);
+  if (cookie_file->ops.seek == nullptr) {
+    errno = EINVAL;
+    return -1;
+  }
+  off64_t offset64 = offset;
+  return cookie_file->ops.seek(cookie_file->cookie, &offset64, whence);
+}
+
+int close_func(File *f) {
+  auto cookie_file = reinterpret_cast<CookieFile *>(f);
+  if (cookie_file->ops.close == nullptr)
+    return 0;
+  return cookie_file->ops.close(cookie_file->cookie);
+}
+
+int flush_func(File *f) { return 0; }
+
+} // anonymous namespace
+
+LLVM_LIBC_FUNCTION(::FILE *, fopencookie,
+                   (void *cookie, const char *mode,
+                    cookie_io_functions_t ops)) {
+  auto modeflags = File::mode_flags(mode);
+  void *buffer = malloc(File::DEFAULT_BUFFER_SIZE);
+  auto *file = reinterpret_cast<CookieFile *>(malloc(sizeof(CookieFile)));
+  if (file == nullptr)
+    return nullptr;
+
+  File::init(file, &write_func, &read_func, &seek_func, &close_func,
+             &flush_func, buffer, File::DEFAULT_BUFFER_SIZE,
+             0,    // Default buffering style
+             true, // Owned buffer
+             modeflags);
+  file->cookie = cookie;
+  file->ops = ops;
+
+  return reinterpret_cast<::FILE *>(file);
+}
+
+} // namespace __llvm_libc

libc/src/stdio/fopencookie.h

@@ -0,0 +1,21 @@
+//===-- Implementation header of fopencookie --------------------*- 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_STDIO_FOPENCOOKIE_H
+#define LLVM_LIBC_SRC_STDIO_FOPENCOOKIE_H
+
+#include <stdio.h>
+
+namespace __llvm_libc {
+
+::FILE *fopencookie(void *cookie, const char *__restrict mode,
+                    cookie_io_functions_t desc);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_STDIO_FOPENCOOKIE_H

libc/test/src/stdio/CMakeLists.txt

@@ -30,6 +30,28 @@ add_libc_unittest(
     libc.src.stdio.fwrite_unlocked
 )
 
+add_libc_unittest(
+  fopencookie_test
+  SUITE
+    libc_stdio_unittests
+  SRCS
+    fopencookie_test.cpp
+  DEPENDS
+    libc.include.errno
+    libc.include.stdio
+    libc.include.stdlib
+    libc.src.stdio.fclose
+    libc.src.stdio.fflush
+    libc.src.stdio.fopencookie
+    libc.src.stdio.fread
+    libc.src.stdio.fseek
+    libc.src.stdio.fwrite
+)
+
+target_link_libraries(
+  libc.test.src.stdio.fopencookie_test PRIVATE LibcMemoryHelpers
+)
+
 add_subdirectory(printf_core)
 
 add_subdirectory(testdata)