[libc] Add chown and getgid implementations #166434

shubhe25p · 2025-11-04T19:45:22Z

Implements chown and getgid per the POSIX specification and adds corresponding unit tests. getgid is added as it is required by the chown unit tests. This PR will address #165785

llvmbot · 2025-11-04T19:45:57Z

@llvm/pr-subscribers-libc

Author: Shubh Pachchigar (shubhe25p)

Changes

Implements chown and getgid per the POSIX specification and adds corresponding unit tests. getgid is added as it is required by the chown unit tests. This PR will address #165785

Full diff: https://github.com/llvm/llvm-project/pull/166434.diff

13 Files Affected:

(modified) libc/config/linux/x86_64/entrypoints.txt (+2)
(modified) libc/hdr/types/CMakeLists.txt (+8)
(added) libc/hdr/types/gid_t.h (+22)
(modified) libc/include/unistd.yaml (+15)
(modified) libc/src/unistd/CMakeLists.txt (+14)
(added) libc/src/unistd/chown.h (+22)
(added) libc/src/unistd/getgid.h (+22)
(modified) libc/src/unistd/linux/CMakeLists.txt (+29)
(added) libc/src/unistd/linux/chown.cpp (+29)
(added) libc/src/unistd/linux/getgid.cpp (+23)
(modified) libc/test/src/unistd/CMakeLists.txt (+30)
(added) libc/test/src/unistd/chown_test.cpp (+51)
(added) libc/test/src/unistd/getgid_test.cpp (+15)

diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 7a8d74a4e5da9..a44e2041e57f2 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -326,6 +326,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     # unistd.h entrypoints
     libc.src.unistd.access
     libc.src.unistd.chdir
+    libc.src.unistd.chown
     libc.src.unistd.close
     libc.src.unistd.dup
     libc.src.unistd.dup2
@@ -344,6 +345,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.unistd.getppid
     libc.src.unistd.getsid
     libc.src.unistd.gettid
+    libc.src.unistd.getgid
     libc.src.unistd.getuid
     libc.src.unistd.isatty
     libc.src.unistd.link
diff --git a/libc/hdr/types/CMakeLists.txt b/libc/hdr/types/CMakeLists.txt
index 225843924c243..433c47b174766 100644
--- a/libc/hdr/types/CMakeLists.txt
+++ b/libc/hdr/types/CMakeLists.txt
@@ -479,3 +479,11 @@ add_proxy_header_library(
     libc.include.llvm-libc-types.struct_rlimit
     libc.include.sys_resource
 )
+
+add_proxy_header_library(
+  gid_t
+  HDRS
+    gid_t.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.gid_t
+)
diff --git a/libc/hdr/types/gid_t.h b/libc/hdr/types/gid_t.h
new file mode 100644
index 0000000000000..bc274aaa9a8a8
--- /dev/null
+++ b/libc/hdr/types/gid_t.h
@@ -0,0 +1,22 @@
+//===-- Proxy for gid_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_HDR_TYPES_GID_T_H
+#define LLVM_LIBC_HDR_TYPES_GID_T_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/gid_t.h"
+
+#else // Overlay mode
+
+#include <sys/types.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_GID_T_H
diff --git a/libc/include/unistd.yaml b/libc/include/unistd.yaml
index 2ff86eafaf550..0e5b22e627b67 100644
--- a/libc/include/unistd.yaml
+++ b/libc/include/unistd.yaml
@@ -3,6 +3,7 @@ header_template: unistd.h.def
 macros: []
 types:
   - type_name: uid_t
+  - type_name: gid_t
   - type_name: ssize_t
   - type_name: size_t
   - type_name: pid_t
@@ -54,6 +55,14 @@ functions:
     return_type: int
     arguments:
       - type: const char *
+  - name: chown
+    standards:
+      - POSIX
+    return_type: int
+    arguments:
+      - type: const char *
+      - type: uid_t
+      - type: gid_t
   - name: close
     standards:
       - POSIX
@@ -195,6 +204,12 @@ functions:
     return_type: uid_t
     arguments:
       - type: void
+  - name: getgid
+    standards:
+      - POSIX
+    return_type: gid_t
+    arguments:
+      - type: void
   - name: isatty
     standards:
       - POSIX
diff --git a/libc/src/unistd/CMakeLists.txt b/libc/src/unistd/CMakeLists.txt
index 78c3bf8442fab..337480cbbf928 100644
--- a/libc/src/unistd/CMakeLists.txt
+++ b/libc/src/unistd/CMakeLists.txt
@@ -27,6 +27,13 @@ add_entrypoint_object(
     .${LIBC_TARGET_OS}.chdir
 )
 
+add_entrypoint_object(
+  chown
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.chown
+)
+
 add_entrypoint_object(
   close
   ALIAS
@@ -160,6 +167,13 @@ add_entrypoint_object(
     .${LIBC_TARGET_OS}.getuid
 )
 
+add_entrypoint_object(
+  getgid
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.getgid
+)
+
 add_entrypoint_object(
   isatty
   ALIAS
diff --git a/libc/src/unistd/chown.h b/libc/src/unistd/chown.h
new file mode 100644
index 0000000000000..e5cae67c7f344
--- /dev/null
+++ b/libc/src/unistd/chown.h
@@ -0,0 +1,22 @@
+//===-- Implementation header for chown -------------------------*- 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_CHOWN_H
+#define LLVM_LIBC_SRC_UNISTD_CHOWN_H
+
+#include "src/__support/macros/config.h"
+#include "hdr/types/uid_t.h"
+#include "hdr/types/gid_t.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int chown(const char *path, uid_t owner, gid_t group);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_UNISTD_CHOWN_H
diff --git a/libc/src/unistd/getgid.h b/libc/src/unistd/getgid.h
new file mode 100644
index 0000000000000..eed0b20d688b1
--- /dev/null
+++ b/libc/src/unistd/getgid.h
@@ -0,0 +1,22 @@
+//===-- Implementation header for getgid ------------------------*- 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_GETGID_H
+#define LLVM_LIBC_SRC_UNISTD_GETGID_H
+
+#include "hdr/types/gid_t.h"
+#include "hdr/unistd_macros.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+gid_t getgid();
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_UNISTD_GETGID_H
diff --git a/libc/src/unistd/linux/CMakeLists.txt b/libc/src/unistd/linux/CMakeLists.txt
index 4eb3c7d3d7fae..ee2acf3ff2109 100644
--- a/libc/src/unistd/linux/CMakeLists.txt
+++ b/libc/src/unistd/linux/CMakeLists.txt
@@ -25,6 +25,21 @@ add_entrypoint_object(
     libc.src.errno.errno
 )
 
+add_entrypoint_object(
+  chown
+  SRCS
+    chown.cpp
+  HDRS
+    ../chown.h
+  DEPENDS
+    libc.hdr.types.uid_t
+    libc.hdr.types.gid_t
+    libc.include.unistd
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
+)
+
 add_entrypoint_object(
   close
   SRCS
@@ -276,6 +291,20 @@ add_entrypoint_object(
     libc.src.errno.errno
 )
 
+add_entrypoint_object(
+  getgid
+  SRCS
+    getgid.cpp
+  HDRS
+    ../getgid.h
+  DEPENDS
+    libc.hdr.types.gid_t
+    libc.hdr.fcntl_macros
+    libc.include.unistd
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+)
+
 add_entrypoint_object(
   getuid
   SRCS
diff --git a/libc/src/unistd/linux/chown.cpp b/libc/src/unistd/linux/chown.cpp
new file mode 100644
index 0000000000000..c7bf1703ffe57
--- /dev/null
+++ b/libc/src/unistd/linux/chown.cpp
@@ -0,0 +1,29 @@
+//===-- Linux implementation of chown -------------------------------------===//
+//
+// 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/chown.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, chown, (const char *path, uid_t owner, gid_t group)) {
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_chown, path, owner, group);
+  if (ret < 0) {
+    libc_errno = -ret;
+    return -1;
+  }
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/unistd/linux/getgid.cpp b/libc/src/unistd/linux/getgid.cpp
new file mode 100644
index 0000000000000..1656fd601d843
--- /dev/null
+++ b/libc/src/unistd/linux/getgid.cpp
@@ -0,0 +1,23 @@
+//===-- Linux implementation of getgid ------------------------------------===//
+//
+// 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/getgid.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(gid_t, getgid, ()) {
+  return LIBC_NAMESPACE::syscall_impl<gid_t>(SYS_getgid);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/src/unistd/CMakeLists.txt b/libc/test/src/unistd/CMakeLists.txt
index 44f28fff9ad39..07070535459ec 100644
--- a/libc/test/src/unistd/CMakeLists.txt
+++ b/libc/test/src/unistd/CMakeLists.txt
@@ -36,6 +36,26 @@ add_libc_unittest(
     libc.test.UnitTest.ErrnoSetterMatcher
 )
 
+add_libc_unittest(
+  chown_test
+  SUITE
+    libc_unistd_unittests
+  SRCS
+    chown_test.cpp
+  DEPENDS
+    libc.hdr.fcntl_macros
+    libc.include.unistd
+    libc.src.errno.errno
+    libc.src.unistd.chown
+    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(
   dup_test
   SUITE
@@ -437,6 +457,16 @@ add_libc_unittest(
     libc.test.UnitTest.ErrnoCheckingTest
 )
 
+add_libc_unittest(
+  getgid_test
+  SUITE
+    libc_unistd_unittests
+  SRCS
+    getgid_test.cpp
+  DEPENDS
+    libc.src.unistd.getgid
+)
+
 add_libc_unittest(
   getpid_test
   SUITE
diff --git a/libc/test/src/unistd/chown_test.cpp b/libc/test/src/unistd/chown_test.cpp
new file mode 100644
index 0000000000000..caa1c3deb6a76
--- /dev/null
+++ b/libc/test/src/unistd/chown_test.cpp
@@ -0,0 +1,51 @@
+//===-- Unittests for chown -----------------------------------------------===//
+//
+// 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/chown.h"
+#include "src/unistd/close.h"
+#include "src/unistd/unlink.h"
+#include "src/unistd/getuid.h"
+#include "src/unistd/getgid.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 LlvmLibcChownTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
+
+TEST_F(LlvmLibcChownTest, ChownSuccess) {
+  using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+  uid_t my_uid = LIBC_NAMESPACE::getuid();
+  gid_t my_gid = LIBC_NAMESPACE::getgid();
+  constexpr const char *FILENAME = "chown.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::chown(TEST_FILE, 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(LlvmLibcChownTest, ChownNonExistentFile) {
+  using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
+  ASSERT_THAT(LIBC_NAMESPACE::chown("non-existent-file", 1000, 1000),
+              Fails(ENOENT));
+}
diff --git a/libc/test/src/unistd/getgid_test.cpp b/libc/test/src/unistd/getgid_test.cpp
new file mode 100644
index 0000000000000..77dbad2f18e00
--- /dev/null
+++ b/libc/test/src/unistd/getgid_test.cpp
@@ -0,0 +1,15 @@
+//===-- Unittests for getgid ----------------------------------------------===//
+//
+// 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/getgid.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcGetGidTest, SmokeTest) {
+  // getgid always succeeds. So, we just call it as a smoke test.
+  LIBC_NAMESPACE::getgid();
+}

github-actions · 2025-11-04T19:47:02Z

✅ With the latest revision this PR passed the C/C++ code formatter.

michaelrj-google

Overall looks good, I'll approve one you clean up the clang-format issues and address the comment

libc/src/unistd/linux/CMakeLists.txt

Implements chown and getgid per the POSIX specification and adds corresponding unit tests. getgid is added as it is required by the chown unit tests.

michaelrj-google

LGTM, do you need me to merge this for you?

shubhe25p · 2025-11-05T00:15:30Z

Yes please feel free to merge, I am not sure if I have the permissions.

llvmbot added the libc label Nov 4, 2025

michaelrj-google self-requested a review November 4, 2025 21:07

michaelrj-google reviewed Nov 4, 2025

View reviewed changes

libc/src/unistd/linux/CMakeLists.txt Outdated Show resolved Hide resolved

[libc] Add chown and getgid implementations

1a041ef

Implements chown and getgid per the POSIX specification and adds corresponding unit tests. getgid is added as it is required by the chown unit tests.

shubhe25p force-pushed the br_libc_chown_impl branch from 5a9de31 to 1a041ef Compare November 4, 2025 21:33

shubhe25p requested a review from michaelrj-google November 4, 2025 21:35

michaelrj-google approved these changes Nov 5, 2025

View reviewed changes

michaelrj-google merged commit 0fd0298 into llvm:main Nov 5, 2025
18 of 19 checks passed

michaelrj-google mentioned this pull request Nov 5, 2025

[libc] Implement chown #165785

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