[libc-commits] [libc] [libc] Implement syncfs in unistd (#230855) (PR #231129)
Aman Maurya via libc-commits
libc-commits at lists.llvm.org
Tue Oct 13 05:17:03 PDT 2026
https://github.com/amanmaurya92 updated https://github.com/llvm/llvm-project/pull/231129
>From d859548f27c1c1b5bc841e6f44966f61504cb8dc Mon Sep 17 00:00:00 2001
From: amanmaurya92 <amanmaurya9209 at gmail.com>
Date: Mon, 12 Oct 2026 16:43:38 +0530
Subject: [PATCH 1/2] [libc] Implement syncfs in unistd (#230855)
Implement the Linux extension function syncfs in <unistd.h>.
Fixes #230855
---
libc/config/linux/aarch64/entrypoints.txt | 1 +
libc/config/linux/arm/entrypoints.txt | 1 +
libc/config/linux/riscv/entrypoints.txt | 1 +
libc/config/linux/x86_64/entrypoints.txt | 1 +
libc/include/unistd.yaml | 6 +++
.../linux/syscall_wrappers/CMakeLists.txt | 12 +++++
.../OSUtil/linux/syscall_wrappers/syncfs.h | 37 ++++++++++++++
libc/src/unistd/CMakeLists.txt | 7 +++
libc/src/unistd/linux/CMakeLists.txt | 13 +++++
libc/src/unistd/linux/syncfs.cpp | 32 ++++++++++++
libc/src/unistd/syncfs.h | 25 +++++++++
libc/test/src/unistd/CMakeLists.txt | 20 ++++++++
libc/test/src/unistd/syncfs_test.cpp | 51 +++++++++++++++++++
13 files changed, 207 insertions(+)
create mode 100644 libc/src/__support/OSUtil/linux/syscall_wrappers/syncfs.h
create mode 100644 libc/src/unistd/linux/syncfs.cpp
create mode 100644 libc/src/unistd/syncfs.h
create mode 100644 libc/test/src/unistd/syncfs_test.cpp
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 046d94f429838f..6f278647a3da48 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -508,6 +508,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.unistd.symlink
libc.src.unistd.symlinkat
libc.src.unistd.sync
+ libc.src.unistd.syncfs
libc.src.unistd.tcgetpgrp
libc.src.unistd.tcsetpgrp
libc.src.unistd.truncate
diff --git a/libc/config/linux/arm/entrypoints.txt b/libc/config/linux/arm/entrypoints.txt
index 4e535fe5111d67..262f5bf6edeefe 100644
--- a/libc/config/linux/arm/entrypoints.txt
+++ b/libc/config/linux/arm/entrypoints.txt
@@ -300,6 +300,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.unistd.symlink
libc.src.unistd.symlinkat
libc.src.unistd.sync
+ libc.src.unistd.syncfs
libc.src.unistd.tcgetpgrp
libc.src.unistd.tcsetpgrp
libc.src.unistd.truncate
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index 548a568e80b5ba..efb8e37e339d10 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -528,6 +528,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.unistd.symlink
libc.src.unistd.symlinkat
libc.src.unistd.sync
+ libc.src.unistd.syncfs
libc.src.unistd.tcgetpgrp
libc.src.unistd.tcsetpgrp
libc.src.unistd.truncate
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 600e0e29dbbb2e..a4ffc7ed43d0b9 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -548,6 +548,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.unistd.symlink
libc.src.unistd.symlinkat
libc.src.unistd.sync
+ libc.src.unistd.syncfs
libc.src.unistd.tcgetpgrp
libc.src.unistd.tcsetpgrp
libc.src.unistd.truncate
diff --git a/libc/include/unistd.yaml b/libc/include/unistd.yaml
index 160b909f3af7b4..178691753bd9b9 100644
--- a/libc/include/unistd.yaml
+++ b/libc/include/unistd.yaml
@@ -577,6 +577,12 @@ functions:
return_type: void
arguments:
- type: void
+ - name: syncfs
+ standards:
+ - linux
+ return_type: int
+ arguments:
+ - type: int
- name: sysconf
standards:
- posix
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt b/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
index b5404c9011f1d9..c206e8c32b45e3 100644
--- a/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
@@ -1072,6 +1072,18 @@ add_header_library(
libc.include.sys_syscall
)
+add_header_library(
+ syncfs
+ HDRS
+ syncfs.h
+ DEPENDS
+ libc.src.__support.OSUtil.osutil
+ libc.src.__support.common
+ libc.src.__support.error_or
+ libc.src.__support.macros.config
+ libc.include.sys_syscall
+)
+
add_header_library(
dup
HDRS
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/syncfs.h b/libc/src/__support/OSUtil/linux/syscall_wrappers/syncfs.h
new file mode 100644
index 00000000000000..7c9ff443345c0f
--- /dev/null
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/syncfs.h
@@ -0,0 +1,37 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Syscall wrapper for syncfs.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_SYNCFS_H
+#define LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_SYNCFS_H
+
+#include "src/__support/OSUtil/linux/syscall.h" // syscall_checked
+#include "src/__support/common.h"
+#include "src/__support/error_or.h"
+#include "src/__support/macros/config.h"
+#include <sys/syscall.h> // For syscall numbers
+
+namespace LIBC_NAMESPACE_DECL {
+namespace linux_syscalls {
+
+LIBC_INLINE ErrorOr<int> syncfs(int fd) {
+#if defined(SYS_syncfs)
+ return syscall_checked<int>(SYS_syncfs, fd);
+#else
+#error "SYS_syncfs syscall not available."
+#endif
+}
+
+} // namespace linux_syscalls
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_OSUTIL_LINUX_SYSCALL_WRAPPERS_SYNCFS_H
diff --git a/libc/src/unistd/CMakeLists.txt b/libc/src/unistd/CMakeLists.txt
index 795224f0e9df48..7b9ddc4b2e45fc 100644
--- a/libc/src/unistd/CMakeLists.txt
+++ b/libc/src/unistd/CMakeLists.txt
@@ -455,6 +455,13 @@ add_entrypoint_object(
.${LIBC_TARGET_OS}.sync
)
+add_entrypoint_object(
+ syncfs
+ ALIAS
+ DEPENDS
+ .${LIBC_TARGET_OS}.syncfs
+)
+
add_entrypoint_object(
sysconf
ALIAS
diff --git a/libc/src/unistd/linux/CMakeLists.txt b/libc/src/unistd/linux/CMakeLists.txt
index 3624f4e1891f2f..dd6ef72bb091f6 100644
--- a/libc/src/unistd/linux/CMakeLists.txt
+++ b/libc/src/unistd/linux/CMakeLists.txt
@@ -806,6 +806,19 @@ add_entrypoint_object(
libc.src.__support.macros.config
)
+add_entrypoint_object(
+ syncfs
+ SRCS
+ syncfs.cpp
+ HDRS
+ ../syncfs.h
+ DEPENDS
+ libc.src.__support.OSUtil.linux.syscall_wrappers.syncfs
+ libc.src.__support.common
+ libc.src.__support.libc_errno
+ libc.src.__support.macros.config
+)
+
add_entrypoint_object(
sysconf
SRCS
diff --git a/libc/src/unistd/linux/syncfs.cpp b/libc/src/unistd/linux/syncfs.cpp
new file mode 100644
index 00000000000000..34bcdb98b0c17d
--- /dev/null
+++ b/libc/src/unistd/linux/syncfs.cpp
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Linux implementation of syncfs.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/unistd/syncfs.h"
+
+#include "src/__support/OSUtil/linux/syscall_wrappers/syncfs.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, syncfs, (int fd)) {
+ auto ret = linux_syscalls::syncfs(fd);
+ if (!ret.has_value()) {
+ libc_errno = ret.error();
+ return -1;
+ }
+ return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/unistd/syncfs.h b/libc/src/unistd/syncfs.h
new file mode 100644
index 00000000000000..d97b0502590861
--- /dev/null
+++ b/libc/src/unistd/syncfs.h
@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Implementation header for syncfs.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_UNISTD_SYNCFS_H
+#define LLVM_LIBC_SRC_UNISTD_SYNCFS_H
+
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int syncfs(int fd);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_UNISTD_SYNCFS_H
diff --git a/libc/test/src/unistd/CMakeLists.txt b/libc/test/src/unistd/CMakeLists.txt
index 89d6dcece5e108..f00071aebac9e8 100644
--- a/libc/test/src/unistd/CMakeLists.txt
+++ b/libc/test/src/unistd/CMakeLists.txt
@@ -601,6 +601,26 @@ add_libc_test(
libc.src.unistd.sync
)
+add_libc_test(
+ syncfs_test
+ SUITE
+ libc_unistd_unittests
+ SRCS
+ syncfs_test.cpp
+ DEPENDS
+ libc.hdr.errno_macros
+ libc.hdr.fcntl_macros
+ libc.hdr.sys_stat_macros
+ libc.src.__support.CPP.scope
+ libc.src.fcntl.open
+ libc.src.unistd.close
+ libc.src.unistd.syncfs
+ libc.src.unistd.unlink
+ libc.src.unistd.write
+ libc.test.UnitTest.ErrnoCheckingTest
+ libc.test.UnitTest.ErrnoSetterMatcher
+)
+
add_libc_test(
tcgetpgrp_test
SUITE
diff --git a/libc/test/src/unistd/syncfs_test.cpp b/libc/test/src/unistd/syncfs_test.cpp
new file mode 100644
index 00000000000000..a257ea2212ad8a
--- /dev/null
+++ b/libc/test/src/unistd/syncfs_test.cpp
@@ -0,0 +1,51 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Unittests for syncfs.
+///
+//===----------------------------------------------------------------------===//
+
+#include "hdr/errno_macros.h"
+#include "hdr/fcntl_macros.h"
+#include "hdr/sys_stat_macros.h"
+#include "src/__support/CPP/scope.h"
+#include "src/fcntl/open.h"
+#include "src/unistd/close.h"
+#include "src/unistd/syncfs.h"
+#include "src/unistd/unlink.h"
+#include "src/unistd/write.h"
+#include "test/UnitTest/ErrnoCheckingTest.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
+using LlvmLibcSyncfsTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
+
+TEST_F(LlvmLibcSyncfsTest, BasicSync) {
+ constexpr const char *FILENAME = "syncfs.test";
+ auto test_file = libc_make_test_file_path(FILENAME);
+ constexpr const char WRITE_DATA[] = "hello, syncfs";
+ constexpr ssize_t WRITE_SIZE = sizeof(WRITE_DATA);
+
+ int fd = LIBC_NAMESPACE::open(test_file, O_WRONLY | O_CREAT, S_IRWXU);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(fd, 0);
+
+ LIBC_NAMESPACE::cpp::scope_exit cleanup(
+ [&] { EXPECT_THAT(LIBC_NAMESPACE::unlink(test_file), Succeeds(0)); });
+
+ ASSERT_THAT(LIBC_NAMESPACE::write(fd, WRITE_DATA, WRITE_SIZE),
+ Succeeds(WRITE_SIZE));
+ ASSERT_THAT(LIBC_NAMESPACE::syncfs(fd), Succeeds(0));
+ ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
+}
+
+TEST_F(LlvmLibcSyncfsTest, BadFd) {
+ ASSERT_THAT(LIBC_NAMESPACE::syncfs(-1), Fails(EBADF));
+}
>From d17accd3db03303beeeca7414c7c53768fb86cc5 Mon Sep 17 00:00:00 2001
From: amanmaurya92 <amanmaurya9209 at gmail.com>
Date: Tue, 13 Oct 2026 17:45:53 +0530
Subject: [PATCH 2/2] [libc] Drop #if in syncfs syscall wrapper
---
libc/src/__support/OSUtil/linux/syscall_wrappers/syncfs.h | 4 ----
1 file changed, 4 deletions(-)
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/syncfs.h b/libc/src/__support/OSUtil/linux/syscall_wrappers/syncfs.h
index 7c9ff443345c0f..0585f066341795 100644
--- a/libc/src/__support/OSUtil/linux/syscall_wrappers/syncfs.h
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/syncfs.h
@@ -24,11 +24,7 @@ namespace LIBC_NAMESPACE_DECL {
namespace linux_syscalls {
LIBC_INLINE ErrorOr<int> syncfs(int fd) {
-#if defined(SYS_syncfs)
return syscall_checked<int>(SYS_syncfs, fd);
-#else
-#error "SYS_syncfs syscall not available."
-#endif
}
} // namespace linux_syscalls
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