[libc] Implement fchown#167286
Merged
michaelrj-google merged 7 commits intollvm:mainfrom Nov 11, 2025
Merged
Conversation
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
Member
|
@llvm/pr-subscribers-libc Author: Anshul Nigham (nigham) ChangesImplements fchown fixes: #166856 Full diff: https://github.com/llvm/llvm-project/pull/167286.diff 9 Files Affected:
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index e0dd15b803253..144237aee7f93 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -327,6 +327,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.unistd.execve
libc.src.unistd.faccessat
libc.src.unistd.fchdir
+ libc.src.unistd.fchown
libc.src.unistd.fpathconf
libc.src.unistd.fsync
libc.src.unistd.ftruncate
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index a44e2041e57f2..f4012514fe20e 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -334,6 +334,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.unistd.execve
libc.src.unistd.faccessat
libc.src.unistd.fchdir
+ libc.src.unistd.fchown
libc.src.unistd.fpathconf
libc.src.unistd.fsync
libc.src.unistd.ftruncate
diff --git a/libc/include/unistd.yaml b/libc/include/unistd.yaml
index 0e5b22e627b67..3f5e957768533 100644
--- a/libc/include/unistd.yaml
+++ b/libc/include/unistd.yaml
@@ -120,6 +120,14 @@ functions:
return_type: int
arguments:
- type: int
+ - name: fchown
+ standards:
+ - POSIX
+ return_type: int
+ arguments:
+ - type: int
+ - type: uid_t
+ - type: gid_t
- name: fork
standards:
- POSIX
diff --git a/libc/src/unistd/CMakeLists.txt b/libc/src/unistd/CMakeLists.txt
index 337480cbbf928..b7444a4722b0d 100644
--- a/libc/src/unistd/CMakeLists.txt
+++ b/libc/src/unistd/CMakeLists.txt
@@ -76,6 +76,13 @@ add_entrypoint_object(
.${LIBC_TARGET_OS}.fchdir
)
+add_entrypoint_object(
+ fchown
+ ALIAS
+ DEPENDS
+ .${LIBC_TARGET_OS}.fchown
+)
+
add_entrypoint_object(
fork
ALIAS
diff --git a/libc/src/unistd/fchown.h b/libc/src/unistd/fchown.h
new file mode 100644
index 0000000000000..575f6173e980f
--- /dev/null
+++ b/libc/src/unistd/fchown.h
@@ -0,0 +1,22 @@
+//===-- Implementation header for fchown ------------------------*- 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_FCHOWN_H_
+#define LLVM_LIBC_SRC_UNISTD_FCHOWN_H_
+
+#include "hdr/types/gid_t.h"
+#include "hdr/types/uid_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int fchown(int fildes, uid_t owner, gid_t group);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_UNISTD_FCHOWN_H_
diff --git a/libc/src/unistd/linux/CMakeLists.txt b/libc/src/unistd/linux/CMakeLists.txt
index c2dacc6456e27..c45b6ef1c5d80 100644
--- a/libc/src/unistd/linux/CMakeLists.txt
+++ b/libc/src/unistd/linux/CMakeLists.txt
@@ -120,6 +120,20 @@ add_entrypoint_object(
libc.src.errno.errno
)
+add_entrypoint_object(
+ fchown
+ SRCS
+ fchown.cpp
+ HDRS
+ ../fchown.h
+ DEPENDS
+ libc.hdr.types.uid_t
+ libc.hdr.types.gid_t
+ libc.include.sys_syscall
+ libc.src.__support.OSUtil.osutil
+ libc.src.errno.errno
+)
+
add_entrypoint_object(
fork
SRCS
diff --git a/libc/src/unistd/linux/fchown.cpp b/libc/src/unistd/linux/fchown.cpp
new file mode 100644
index 0000000000000..63cad81ea585b
--- /dev/null
+++ b/libc/src/unistd/linux/fchown.cpp
@@ -0,0 +1,29 @@
+//===-- Linux implementation of fchown ------------------------------------===//
+//
+// 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/fchown.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.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, fchown, (int fildes, uid_t owner, gid_t group)) {
+ int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_fchown, fildes, owner, group);
+ if (ret < 0) {
+ libc_errno = -ret;
+ return -1;
+ }
+ return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/src/unistd/CMakeLists.txt b/libc/test/src/unistd/CMakeLists.txt
index 07070535459ec..3012ea9a466f4 100644
--- a/libc/test/src/unistd/CMakeLists.txt
+++ b/libc/test/src/unistd/CMakeLists.txt
@@ -146,6 +146,26 @@ add_libc_unittest(
libc.test.UnitTest.ErrnoSetterMatcher
)
+add_libc_unittest(
+ fchown_test
+ SUITE
+ libc_unistd_unittests
+ SRCS
+ fchown_test.cpp
+ DEPENDS
+ libc.hdr.fcntl_macros
+ libc.include.unistd
+ libc.src.errno.errno
+ libc.src.unistd.fchown
+ libc.src.unistd.close
+ libc.src.unistd.unlink
+ libc.src.fcntl.open
+ libc.src.unistd.getuid
+ libc.src.unistd.getgid
+ libc.test.UnitTest.ErrnoCheckingTest
+ libc.test.UnitTest.ErrnoSetterMatcher
+)
+
add_libc_unittest(
ftruncate_test
SUITE
diff --git a/libc/test/src/unistd/fchown_test.cpp b/libc/test/src/unistd/fchown_test.cpp
new file mode 100644
index 0000000000000..868814e503be6
--- /dev/null
+++ b/libc/test/src/unistd/fchown_test.cpp
@@ -0,0 +1,50 @@
+//===-- Unittests for fchown ----------------------------------------------===//
+//
+// 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/unistd/close.h"
+#include "src/unistd/fchown.h"
+#include "src/unistd/getgid.h"
+#include "src/unistd/getuid.h"
+#include "src/unistd/unlink.h"
+
+#include "test/UnitTest/ErrnoCheckingTest.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+#include "hdr/fcntl_macros.h"
+#include <sys/stat.h>
+
+using LlvmLibcFchownTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
+
+TEST_F(LlvmLibcFchownTest, FchownSuccess) {
+ using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+ uid_t my_uid = LIBC_NAMESPACE::getuid();
+ gid_t my_gid = LIBC_NAMESPACE::getgid();
+ constexpr const char *FILENAME = "fchown.test";
+ auto TEST_FILE = libc_make_test_file_path(FILENAME);
+
+ // Create a test file.
+ int write_fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(write_fd, 0);
+
+ // Change the ownership of the file.
+ ASSERT_THAT(LIBC_NAMESPACE::fchown(write_fd, my_uid, my_gid), Succeeds(0));
+
+ // Close the file descriptor.
+ ASSERT_THAT(LIBC_NAMESPACE::close(write_fd), Succeeds(0));
+
+ // Clean up the test file.
+ ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FILE), Succeeds(0));
+}
+
+TEST_F(LlvmLibcFchownTest, ChownInvalidFileDescriptor) {
+ using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
+ ASSERT_THAT(LIBC_NAMESPACE::fchown(-1, 1000, 1000), Fails(EBADF));
+}
|
Contributor
michaelrj-google
left a comment
michaelrj-google
left a comment
There was a problem hiding this comment.
Overall looks good, a couple minor nits.
|
|
||
| #include "src/__support/OSUtil/syscall.h" // For internal syscall function. | ||
| #include "src/__support/common.h" | ||
|
|
Contributor
There was a problem hiding this comment.
add includes for the proxy headers here, ideally we'd include everything we use.
Suggested change
| #include "hdr/types/gid_t.h" | |
| #include "hdr/types/uid_t.h" |
libc/src/unistd/fchown.h
Outdated
| // | ||
| //===----------------------------------------------------------------------===// | ||
|
|
||
| #ifndef LLVM_LIBC_SRC_UNISTD_FCHOWN_H_ |
Contributor
There was a problem hiding this comment.
these header guards have an extra underscore at the end that they don't need.
Suggested change
| #ifndef LLVM_LIBC_SRC_UNISTD_FCHOWN_H_ | |
| #ifndef LLVM_LIBC_SRC_UNISTD_FCHOWN_H |
libc/test/src/unistd/fchown_test.cpp
Outdated
| ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FILE), Succeeds(0)); | ||
| } | ||
|
|
||
| TEST_F(LlvmLibcFchownTest, ChownInvalidFileDescriptor) { |
Contributor
There was a problem hiding this comment.
nit: Fix the test name
michaelrj-google
approved these changes
Nov 11, 2025
Contributor
michaelrj-google
left a comment
michaelrj-google
left a comment
There was a problem hiding this comment.
LGTM, you might want to add Fixes #<issue number> to the commit description on github to automatically close the issue when you merge.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Implements fchown
fixes: #166856