[libc-commits] [libc] de9ad51 - [libc] Implement mkfifo (#223566)
via libc-commits
libc-commits at lists.llvm.org
Tue Sep 15 17:59:27 PDT 2026
Author: Michael Jones
Date: 2026-09-15T17:59:22-07:00
New Revision: de9ad513460a1a5439b0b8d6d5c7a51a3634bc20
URL: https://github.com/llvm/llvm-project/commit/de9ad513460a1a5439b0b8d6d5c7a51a3634bc20
DIFF: https://github.com/llvm/llvm-project/commit/de9ad513460a1a5439b0b8d6d5c7a51a3634bc20.diff
LOG: [libc] Implement mkfifo (#223566)
Implements the mkfifo function from POSIX, and tests.
Fixes: #220758
Assisted-by: Automated Tooling, Human Reviewed
Added:
libc/src/__support/OSUtil/linux/syscall_wrappers/mknodat.h
libc/src/sys/stat/linux/mkfifo.cpp
libc/src/sys/stat/mkfifo.h
libc/test/src/sys/stat/mkfifo_test.cpp
Modified:
libc/config/linux/aarch64/entrypoints.txt
libc/config/linux/riscv/entrypoints.txt
libc/config/linux/x86_64/entrypoints.txt
libc/include/sys/stat.yaml
libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
libc/src/sys/stat/CMakeLists.txt
libc/src/sys/stat/linux/CMakeLists.txt
libc/test/src/sys/stat/CMakeLists.txt
Removed:
################################################################################
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index bc76076582fc1..588845ea95831 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -353,6 +353,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.sys.stat.lstat
libc.src.sys.stat.mkdir
libc.src.sys.stat.mkdirat
+ libc.src.sys.stat.mkfifo
libc.src.sys.stat.stat
libc.src.sys.stat.umask
libc.src.sys.stat.utimensat
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index 77c06949c1425..580d242fac20b 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -384,6 +384,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.sys.stat.lstat
libc.src.sys.stat.mkdir
libc.src.sys.stat.mkdirat
+ libc.src.sys.stat.mkfifo
libc.src.sys.stat.stat
libc.src.sys.stat.umask
libc.src.sys.stat.utimensat
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index ff7b7099d28c6..263437c11fabd 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -389,6 +389,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.sys.stat.lstat
libc.src.sys.stat.mkdir
libc.src.sys.stat.mkdirat
+ libc.src.sys.stat.mkfifo
libc.src.sys.stat.stat
libc.src.sys.stat.umask
libc.src.sys.stat.utimensat
diff --git a/libc/include/sys/stat.yaml b/libc/include/sys/stat.yaml
index b12e2ac620a4f..3c75ce3d796cb 100644
--- a/libc/include/sys/stat.yaml
+++ b/libc/include/sys/stat.yaml
@@ -58,6 +58,11 @@ functions:
- type: int
- type: const char *
- type: mode_t
+ - name: mkfifo
+ return_type: int
+ arguments:
+ - type: const char *
+ - type: mode_t
- name: stat
return_type: int
arguments:
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt b/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
index 3857c736086dc..17665f87dfcd8 100644
--- a/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
@@ -603,6 +603,20 @@ add_header_library(
libc.include.sys_syscall
)
+add_header_library(
+ mknodat
+ HDRS
+ mknodat.h
+ DEPENDS
+ libc.src.__support.OSUtil.osutil
+ libc.src.__support.common
+ libc.src.__support.error_or
+ libc.src.__support.macros.config
+ libc.hdr.types.dev_t
+ libc.hdr.types.mode_t
+ libc.include.sys_syscall
+)
+
add_header_library(
chmod
HDRS
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/mknodat.h b/libc/src/__support/OSUtil/linux/syscall_wrappers/mknodat.h
new file mode 100644
index 0000000000000..50fd804ae61b2
--- /dev/null
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/mknodat.h
@@ -0,0 +1,40 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 mknodat.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_MKNODAT_H
+#define LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_MKNODAT_H
+
+#include "hdr/types/dev_t.h"
+#include "hdr/types/mode_t.h"
+#include "src/__support/OSUtil/linux/syscall.h" // For 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 {
+
+// Note that the kernel expects |dev| in its own old-style encoding
+// ((major << 8) | minor, with the extended bits), which is not necessarily the
+// encoding of dev_t. Callers creating device nodes must encode it themselves;
+// callers creating FIFOs and sockets pass 0.
+LIBC_INLINE ErrorOr<int> mknodat(int dfd, const char *path, mode_t mode,
+ dev_t dev) {
+ return syscall_checked<int>(SYS_mknodat, dfd, path, mode, dev);
+}
+
+} // namespace linux_syscalls
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_MKNODAT_H
diff --git a/libc/src/sys/stat/CMakeLists.txt b/libc/src/sys/stat/CMakeLists.txt
index 7338fac02bc29..ae1a3f76078f1 100644
--- a/libc/src/sys/stat/CMakeLists.txt
+++ b/libc/src/sys/stat/CMakeLists.txt
@@ -51,6 +51,13 @@ add_entrypoint_object(
.${LIBC_TARGET_OS}.mkdirat
)
+add_entrypoint_object(
+ mkfifo
+ ALIAS
+ DEPENDS
+ .${LIBC_TARGET_OS}.mkfifo
+)
+
add_entrypoint_object(
stat
ALIAS
diff --git a/libc/src/sys/stat/linux/CMakeLists.txt b/libc/src/sys/stat/linux/CMakeLists.txt
index 52ae4566a2b87..b087fc927459c 100644
--- a/libc/src/sys/stat/linux/CMakeLists.txt
+++ b/libc/src/sys/stat/linux/CMakeLists.txt
@@ -60,6 +60,20 @@ add_entrypoint_object(
libc.src.errno.errno
)
+add_entrypoint_object(
+ mkfifo
+ SRCS
+ mkfifo.cpp
+ HDRS
+ ../mkfifo.h
+ DEPENDS
+ libc.hdr.fcntl_macros
+ libc.hdr.sys_stat_macros
+ libc.hdr.types.mode_t
+ libc.src.__support.OSUtil.linux.syscall_wrappers.mknodat
+ libc.src.errno.errno
+)
+
add_entrypoint_object(
stat
SRCS
diff --git a/libc/src/sys/stat/linux/mkfifo.cpp b/libc/src/sys/stat/linux/mkfifo.cpp
new file mode 100644
index 0000000000000..7d1025ea0f59f
--- /dev/null
+++ b/libc/src/sys/stat/linux/mkfifo.cpp
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 mkfifo.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/sys/stat/mkfifo.h"
+
+#include "hdr/fcntl_macros.h"
+#include "hdr/sys_stat_macros.h"
+#include "hdr/types/mode_t.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/mknodat.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, mkfifo, (const char *path, mode_t mode)) {
+ auto result = linux_syscalls::mknodat(AT_FDCWD, path, mode | S_IFIFO, 0);
+ if (!result) {
+ libc_errno = result.error();
+ return -1;
+ }
+ return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/sys/stat/mkfifo.h b/libc/src/sys/stat/mkfifo.h
new file mode 100644
index 0000000000000..c814159bb215a
--- /dev/null
+++ b/libc/src/sys/stat/mkfifo.h
@@ -0,0 +1,26 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 mkfifo.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_SYS_STAT_MKFIFO_H
+#define LLVM_LIBC_SRC_SYS_STAT_MKFIFO_H
+
+#include "hdr/types/mode_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int mkfifo(const char *path, mode_t mode);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_SYS_STAT_MKFIFO_H
diff --git a/libc/test/src/sys/stat/CMakeLists.txt b/libc/test/src/sys/stat/CMakeLists.txt
index 3e87a11b05e6e..32ce8f50c0ef1 100644
--- a/libc/test/src/sys/stat/CMakeLists.txt
+++ b/libc/test/src/sys/stat/CMakeLists.txt
@@ -75,6 +75,26 @@ add_libc_test(
libc.test.UnitTest.ErrnoSetterMatcher
)
+add_libc_test(
+ mkfifo_test
+ SUITE
+ libc_sys_stat_unittests
+ SRCS
+ mkfifo_test.cpp
+ DEPENDS
+ libc.hdr.errno_macros
+ libc.hdr.sys_stat_macros
+ libc.hdr.types.mode_t
+ libc.hdr.types.struct_stat
+ libc.src.errno.errno
+ libc.src.sys.stat.mkfifo
+ libc.src.sys.stat.stat
+ libc.src.sys.stat.umask
+ libc.src.unistd.unlink
+ libc.test.UnitTest.ErrnoCheckingTest
+ libc.test.UnitTest.ErrnoSetterMatcher
+)
+
add_libc_test(
stat_test
SUITE
diff --git a/libc/test/src/sys/stat/mkfifo_test.cpp b/libc/test/src/sys/stat/mkfifo_test.cpp
new file mode 100644
index 0000000000000..df93a03f86653
--- /dev/null
+++ b/libc/test/src/sys/stat/mkfifo_test.cpp
@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 mkfifo.
+///
+//===----------------------------------------------------------------------===//
+
+#include "hdr/errno_macros.h"
+#include "hdr/sys_stat_macros.h"
+#include "hdr/types/mode_t.h"
+#include "hdr/types/struct_stat.h"
+#include "src/sys/stat/mkfifo.h"
+#include "src/sys/stat/stat.h"
+#include "src/sys/stat/umask.h"
+#include "src/unistd/unlink.h"
+#include "test/UnitTest/ErrnoCheckingTest.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
+using LlvmLibcMkfifoTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
+
+TEST_F(LlvmLibcMkfifoTest, CreateAndRemove) {
+ constexpr const char *FILENAME = "testdata/mkfifo.testfifo";
+ auto TEST_FIFO = libc_make_test_file_path(FILENAME);
+ constexpr mode_t FIFO_MODE = S_IRUSR | S_IWUSR;
+
+ // Clear the file creation mask so that the resulting permission bits are
+ // exactly the requested ones.
+ mode_t old_mask = LIBC_NAMESPACE::umask(0);
+ ASSERT_THAT(LIBC_NAMESPACE::mkfifo(TEST_FIFO, FIFO_MODE), Succeeds(0));
+ LIBC_NAMESPACE::umask(old_mask);
+
+ // The created file must be a FIFO with the requested permissions, which
+ // verifies that S_IFIFO was requested and that mode was passed along.
+ struct stat statbuf;
+ ASSERT_THAT(LIBC_NAMESPACE::stat(TEST_FIFO, &statbuf), Succeeds(0));
+ ASSERT_TRUE(S_ISFIFO(statbuf.st_mode));
+ ASSERT_EQ(static_cast<int>(statbuf.st_mode & 07777),
+ static_cast<int>(FIFO_MODE));
+
+ ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FIFO), Succeeds(0));
+}
+
+TEST_F(LlvmLibcMkfifoTest, BadPath) {
+ constexpr const char *FILENAME = "testdata/non-existent-dir/mkfifo.testfifo";
+ auto TEST_FIFO = libc_make_test_file_path(FILENAME);
+
+ ASSERT_THAT(LIBC_NAMESPACE::mkfifo(TEST_FIFO, S_IRUSR | S_IWUSR),
+ Fails(ENOENT));
+}
More information about the libc-commits
mailing list