[libc][c11] Add stdio.h's rename() function

libc/config/linux/aarch64/entrypoints.txt

@@ -165,6 +165,7 @@ set(TARGET_LIBC_ENTRYPOINTS
 
     # stdio.h entrypoints
     libc.src.stdio.remove
+    libc.src.stdio.rename
     libc.src.stdio.sprintf
     libc.src.stdio.snprintf
     libc.src.stdio.vsprintf

libc/config/linux/riscv/entrypoints.txt

@@ -166,6 +166,7 @@ set(TARGET_LIBC_ENTRYPOINTS
 
     # stdio.h entrypoints
     libc.src.stdio.remove
+    libc.src.stdio.rename
     libc.src.stdio.sprintf
     libc.src.stdio.snprintf
     libc.src.stdio.fprintf

libc/config/linux/x86_64/entrypoints.txt

@@ -197,6 +197,7 @@ set(TARGET_LIBC_ENTRYPOINTS
 
     # stdio.h entrypoints
     libc.src.stdio.remove
+    libc.src.stdio.rename
     libc.src.stdio.sprintf
     libc.src.stdio.snprintf
     libc.src.stdio.fprintf

libc/docs/stdio.rst

@@ -68,7 +68,7 @@ These functions operate on files on the host's system, without using the
 Function_Name  Available
 =============  =========
 remove         |check|
-rename
+rename         |check|
 tmpnam
 =============  =========
 

libc/spec/stdc.td

@@ -695,6 +695,11 @@ def StdC : StandardSpec<"stdc"> {
               RetValSpec<IntType>,
               [ArgSpec<ConstCharPtr>]
           >,
+          FunctionSpec<
+              "rename",
+              RetValSpec<IntType>,
+              [ArgSpec<ConstCharPtr>, ArgSpec<ConstCharPtr>]
+          >,
           FunctionSpec<
               "setbuf",
               RetValSpec<VoidType>,

libc/src/stdio/CMakeLists.txt

@@ -246,6 +246,13 @@ add_entrypoint_object(
     .${LIBC_TARGET_OS}.remove
 )
 
+add_entrypoint_object(
+  rename
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.rename
+)
+
 # These entrypoints have multiple potential implementations.
 add_stdio_entrypoint_object(feof)
 add_stdio_entrypoint_object(feof_unlocked)

libc/src/stdio/linux/CMakeLists.txt

@@ -11,3 +11,15 @@ add_entrypoint_object(
     libc.src.__support.OSUtil.osutil
     libc.src.errno.errno
 )
+
+add_entrypoint_object(
+  rename
+  SRCS
+    rename.cpp
+  HDRS
+    ../rename.h
+  DEPENDS
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
+)

libc/src/stdio/linux/rename.cpp

@@ -0,0 +1,26 @@
+//===-- Linux implementation of rename ------------------------------------===//
+//
+// 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/rename.h"
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(int, rename, (const char *oldpath, const char *newpath)) {
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_rename, oldpath, newpath);
+
+  if (ret >= 0)
+    return 0;
+  libc_errno = -ret;
+  return -1;
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/stdio/rename.h

@@ -0,0 +1,18 @@
+//===-- Implementation header of rename -------------------------*- 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_RENAME_H
+#define LLVM_LIBC_SRC_STDIO_RENAME_H
+
+namespace LIBC_NAMESPACE {
+
+int rename(const char *oldpath, const char *newpath);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDIO_RENAME_H

libc/test/src/stdio/CMakeLists.txt

@@ -353,6 +353,21 @@ if(${LIBC_TARGET_OS} STREQUAL "linux")
       libc.src.unistd.access
       libc.src.unistd.close
   )
+
+  add_libc_test(
+    rename_test
+    SUITE
+      libc_stdio_unittests
+    SRCS
+      rename_test.cpp
+    DEPENDS
+      libc.src.errno.errno
+      libc.src.fcntl.open
+      libc.src.stdio.rename
+      libc.src.unistd.access
+      libc.src.unistd.close
+      libc.test.UnitTest.ErrnoSetterMatcher
+  )
 endif()
 
 add_libc_test(

libc/test/src/stdio/rename_test.cpp

@@ -0,0 +1,49 @@
+//===-- Unittests for rename ----------------------------------------------===//
+//
+// 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/errno/libc_errno.h"
+#include "src/fcntl/open.h"
+#include "src/stdio/rename.h"
+#include "src/unistd/access.h"
+#include "src/unistd/close.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcRenameTest, CreateAndRenameFile) {
+  // The test strategy is to create a file and rename it, and also verify that
+  // it was renamed.
+  LIBC_NAMESPACE::libc_errno = 0;
+  using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
+  using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+
+  constexpr const char *FILENAME0 = "rename.test.file0";
+  auto TEST_FILEPATH0 = libc_make_test_file_path(FILENAME0);
+
+  int fd = LIBC_NAMESPACE::open(TEST_FILEPATH0, O_WRONLY | O_CREAT, S_IRWXU);
+  ASSERT_ERRNO_SUCCESS();
+  ASSERT_GT(fd, 0);
+  ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
+  ASSERT_THAT(LIBC_NAMESPACE::access(TEST_FILEPATH0, F_OK), Succeeds(0));
+
+  constexpr const char *FILENAME1 = "rename.test.file1";
+  auto TEST_FILEPATH1 = libc_make_test_file_path(FILENAME1);
+  ASSERT_THAT(LIBC_NAMESPACE::rename(TEST_FILEPATH0, TEST_FILEPATH1),
+              Succeeds(0));
+  ASSERT_THAT(LIBC_NAMESPACE::access(TEST_FILEPATH1, F_OK), Succeeds(0));
+  ASSERT_THAT(LIBC_NAMESPACE::access(TEST_FILEPATH0, F_OK), Fails(ENOENT));
+}
+
+TEST(LlvmLibcRenameTest, RenameNonExistent) {
+  using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
+
+  constexpr const char *FILENAME1 = "rename.test.file1";
+  auto TEST_FILEPATH1 = libc_make_test_file_path(FILENAME1);
+
+  ASSERT_THAT(LIBC_NAMESPACE::rename("non-existent", TEST_FILEPATH1),
+              Fails(ENOENT));
+}

utils/bazel/llvm-project-overlay/libc/BUILD.bazel

@@ -3230,6 +3230,17 @@ libc_function(
     ],
 )
 
+libc_function(
+    name = "rename",
+    srcs = ["src/stdio/linux/rename.cpp"],
+    hdrs = ["src/stdio/rename.h"],
+    deps = [
+        ":__support_common",
+        ":__support_osutil_syscall",
+        ":errno",
+    ],
+)
+
 ############################### sys/stat targets ###############################
 
 libc_function(