[libc-commits] [libc] [libc] Implement fcntl() function (PR #89507)
via libc-commits
libc-commits at lists.llvm.org
Sat Apr 20 08:28:39 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-libc
Author: Vinayak Dev (vinayakdsci)
<details>
<summary>Changes</summary>
Implements the `fcntl()` function defined in the `fcntl.h` header.
---
Full diff: https://github.com/llvm/llvm-project/pull/89507.diff
9 Files Affected:
- (modified) libc/config/linux/aarch64/entrypoints.txt (+1)
- (modified) libc/config/linux/riscv/entrypoints.txt (+1)
- (modified) libc/config/linux/x86_64/entrypoints.txt (+1)
- (modified) libc/src/fcntl/CMakeLists.txt (+7)
- (added) libc/src/fcntl/fcntl.h (+20)
- (modified) libc/src/fcntl/linux/CMakeLists.txt (+12)
- (added) libc/src/fcntl/linux/fcntl.cpp (+96)
- (modified) libc/test/src/fcntl/CMakeLists.txt (+15)
- (added) libc/test/src/fcntl/fcntl_test.cpp (+146)
``````````diff
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 1ac6bd93000082..5606b06967d629 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -22,6 +22,7 @@ set(TARGET_LIBC_ENTRYPOINTS
# fcntl.h entrypoints
libc.src.fcntl.creat
+ libc.src.fcntl.fcntl
libc.src.fcntl.open
libc.src.fcntl.openat
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index 87e82e5eb9a067..1caba997742b8a 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -22,6 +22,7 @@ set(TARGET_LIBC_ENTRYPOINTS
# fcntl.h entrypoints
libc.src.fcntl.creat
+ libc.src.fcntl.fcntl
libc.src.fcntl.open
libc.src.fcntl.openat
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 2d8136536b218b..aec1bd4d5911ba 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -22,6 +22,7 @@ set(TARGET_LIBC_ENTRYPOINTS
# fcntl.h entrypoints
libc.src.fcntl.creat
+ libc.src.fcntl.fcntl
libc.src.fcntl.open
libc.src.fcntl.openat
diff --git a/libc/src/fcntl/CMakeLists.txt b/libc/src/fcntl/CMakeLists.txt
index 0b9ee47c4f7c13..77400e9050d08b 100644
--- a/libc/src/fcntl/CMakeLists.txt
+++ b/libc/src/fcntl/CMakeLists.txt
@@ -9,6 +9,13 @@ add_entrypoint_object(
.${LIBC_TARGET_OS}.creat
)
+add_entrypoint_object(
+ fcntl
+ ALIAS
+ DEPENDS
+ .${LIBC_TARGET_OS}.fcntl
+)
+
add_entrypoint_object(
open
ALIAS
diff --git a/libc/src/fcntl/fcntl.h b/libc/src/fcntl/fcntl.h
new file mode 100644
index 00000000000000..821e498f767fdd
--- /dev/null
+++ b/libc/src/fcntl/fcntl.h
@@ -0,0 +1,20 @@
+//===-- Implementation header of fcntl --------------------------*- 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_FCNTL_FCNTL_H
+#define LLVM_LIBC_SRC_FCNTL_FCNTL_H
+
+#include <fcntl.h>
+
+namespace LIBC_NAMESPACE {
+
+int fcntl(int fd, int cmd, ...);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_FCNTL_FCNTL_H
diff --git a/libc/src/fcntl/linux/CMakeLists.txt b/libc/src/fcntl/linux/CMakeLists.txt
index 87b8d4695c4fc5..f12d57a6b40a7b 100644
--- a/libc/src/fcntl/linux/CMakeLists.txt
+++ b/libc/src/fcntl/linux/CMakeLists.txt
@@ -10,6 +10,18 @@ add_entrypoint_object(
libc.src.errno.errno
)
+add_entrypoint_object(
+ fcntl
+ SRCS
+ fcntl.cpp
+ HDRS
+ ../fcntl.h
+ DEPENDS
+ libc.include.fcntl
+ libc.src.__support.OSUtil.osutil
+ libc.src.errno.errno
+)
+
add_entrypoint_object(
open
SRCS
diff --git a/libc/src/fcntl/linux/fcntl.cpp b/libc/src/fcntl/linux/fcntl.cpp
new file mode 100644
index 00000000000000..12376a518bdfa3
--- /dev/null
+++ b/libc/src/fcntl/linux/fcntl.cpp
@@ -0,0 +1,96 @@
+//===-- Implementation of fcntl -------------------------------------------===//
+//
+// 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/fcntl.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
+
+#include <stdarg.h>
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace {
+struct fowner_ex {
+ int type;
+ pid_t pid;
+};
+} // namespace
+
+// The OFD file locks require special handling for LARGEFILES
+namespace LIBC_NAMESPACE {
+LLVM_LIBC_FUNCTION(int, fcntl, (int fd, int cmd, ...)) {
+ void *arg;
+ va_list varargs;
+ va_start(varargs, cmd);
+ arg = va_arg(varargs, void *);
+ va_end(varargs);
+
+ switch (cmd) {
+ case F_SETLKW:
+ return syscall_impl<int>(SYS_fcntl, fd, cmd, arg);
+ case F_OFD_SETLKW: {
+ struct flock *flk = (struct flock *)arg;
+ // convert the struct to a flock64
+ struct flock64 flk64;
+ flk64.l_type = flk->l_type;
+ flk64.l_whence = flk->l_whence;
+ flk64.l_start = flk->l_start;
+ flk64.l_len = flk->l_len;
+ flk64.l_pid = flk->l_pid;
+ // create a syscall
+ return syscall_impl<int>(SYS_fcntl, fd, cmd, &flk64);
+ }
+ case F_OFD_GETLK:
+ case F_OFD_SETLK: {
+ struct flock *flk = (struct flock *)arg;
+ // convert the struct to a flock64
+ struct flock64 flk64;
+ flk64.l_type = flk->l_type;
+ flk64.l_whence = flk->l_whence;
+ flk64.l_start = flk->l_start;
+ flk64.l_len = flk->l_len;
+ flk64.l_pid = flk->l_pid;
+ // create a syscall
+ int retVal = syscall_impl<int>(SYS_fcntl, fd, cmd, &flk64);
+ // On failure, return
+ if (retVal == -1)
+ return -1;
+ // Check for overflow, i.e. the offsets are not the same when cast
+ // to off_t from off64_t.
+ if ((off_t)flk64.l_len != flk64.l_len ||
+ (off_t)flk64.l_start != flk64.l_start) {
+ libc_errno = EOVERFLOW;
+ return -1;
+ }
+ // Now copy back into flk, in case flk64 got modified
+ flk->l_type = flk64.l_type;
+ flk->l_whence = flk64.l_whence;
+ flk->l_start = flk64.l_start;
+ flk->l_len = flk64.l_len;
+ flk->l_pid = flk64.l_pid;
+ return retVal;
+ }
+ // The general case
+ default: {
+ if (cmd == F_GETOWN) {
+ struct fowner_ex fex;
+ int retVal = syscall_impl<int>(SYS_fcntl, fd, F_GETOWN_EX, &fex);
+ if (retVal == -EINVAL)
+ return syscall_impl<int>(SYS_fcntl, fd, cmd, (void *)arg);
+ if ((uint64_t)retVal <= -4096UL)
+ return fex.type == F_OWNER_PGRP ? -fex.pid : fex.pid;
+
+ libc_errno = -retVal;
+ return -1;
+ }
+ return syscall_impl<int>(SYS_fcntl, fd, cmd, (void *)arg);
+ }
+ }
+}
+} // namespace LIBC_NAMESPACE
diff --git a/libc/test/src/fcntl/CMakeLists.txt b/libc/test/src/fcntl/CMakeLists.txt
index ae39d8d5f878c5..1c99009d5a6d4e 100644
--- a/libc/test/src/fcntl/CMakeLists.txt
+++ b/libc/test/src/fcntl/CMakeLists.txt
@@ -17,6 +17,21 @@ add_libc_unittest(
libc.test.UnitTest.ErrnoSetterMatcher
)
+add_libc_unittest(
+ fcntl_test
+ SUITE
+ libc_fcntl_unittests
+ SRCS
+ fcntl_test.cpp
+ DEPENDS
+ libc.include.fcntl
+ libc.src.errno.errno
+ libc.src.fcntl.fcntl
+ libc.src.fcntl.open
+ libc.src.unistd.close
+ libc.test.UnitTest.ErrnoSetterMatcher
+)
+
add_libc_unittest(
openat_test
SUITE
diff --git a/libc/test/src/fcntl/fcntl_test.cpp b/libc/test/src/fcntl/fcntl_test.cpp
new file mode 100644
index 00000000000000..81a7feaf151cf8
--- /dev/null
+++ b/libc/test/src/fcntl/fcntl_test.cpp
@@ -0,0 +1,146 @@
+//===-- Unittest for fcntl ------------------------------------------------===//
+//
+// 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/fcntl.h"
+#include "src/fcntl/open.h"
+#include "src/unistd/close.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+#include <sys/stat.h>
+
+TEST(LlvmLibcFcntlTest, FcntlDupfd) {
+ using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+ constexpr const char *TEST_FILE = "testdata/fcntl.test";
+ int fd2, fd3;
+ int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_TRUNC, S_IRWXU);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(fd, 0);
+
+ fd2 = LIBC_NAMESPACE::fcntl(fd, F_DUPFD, 0);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(fd2, 0);
+
+ fd3 = LIBC_NAMESPACE::fcntl(fd, F_DUPFD, 10);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(fd3, 0);
+
+ ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
+ ASSERT_THAT(LIBC_NAMESPACE::close(fd2), Succeeds(0));
+ ASSERT_THAT(LIBC_NAMESPACE::close(fd3), Succeeds(0));
+}
+
+TEST(LlvmLibcFcntlTest, FcntlGetFl) {
+ using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+ constexpr const char *TEST_FILE = "testdata/fcntl.test";
+ int retVal;
+ int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_TRUNC, S_IRWXU);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(fd, 0);
+
+ retVal = LIBC_NAMESPACE::fcntl(fd, F_GETFL);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(retVal, -1);
+
+ ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
+}
+
+TEST(LlvmLibcFcntlTest, FcntlSetFl) {
+ using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+ constexpr const char *TEST_FILE = "testdata/fcntl.test";
+
+ int retVal;
+ int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_TRUNC | O_RDWR, S_IRWXU);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(fd, 0);
+
+ retVal = LIBC_NAMESPACE::fcntl(fd, F_GETFL);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(retVal, -1);
+
+ int oldFlags = LIBC_NAMESPACE::fcntl(fd, F_GETFL, 0);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(oldFlags, 0);
+
+ // Add the APPEND flag;
+ oldFlags |= O_APPEND;
+
+ retVal = LIBC_NAMESPACE::fcntl(fd, F_SETFL, oldFlags);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(retVal, -1);
+
+ // Remove the APPEND flag;
+ oldFlags = -oldFlags & O_APPEND;
+
+ retVal = LIBC_NAMESPACE::fcntl(fd, F_SETFL, oldFlags);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(retVal, -1);
+
+ ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
+}
+
+TEST(LlvmLibcFcntlTest, FcntlGetLkRead) {
+ using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+ constexpr const char *TEST_FILE = "testdata/fcntl.test";
+
+ struct flock flk, svflk;
+ int retVal;
+ int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_TRUNC | O_RDONLY);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(fd, 0);
+
+ flk.l_type = F_RDLCK;
+ flk.l_start = 0;
+ flk.l_whence = SEEK_SET;
+ flk.l_len = 50;
+
+ // copy flk into svflk
+ svflk = flk;
+
+ retVal = LIBC_NAMESPACE::fcntl(fd, F_GETLK, &svflk);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(retVal, -1);
+ ASSERT_NE((int)flk.l_type, F_WRLCK); // File should not be write locked.
+
+ retVal = LIBC_NAMESPACE::fcntl(fd, F_SETLK, &svflk);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(retVal, -1);
+
+ ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
+}
+
+TEST(LlvmLibcFcntlTest, FcntlGetLkWrite) {
+ using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+ constexpr const char *TEST_FILE = "testdata/fcntl.test";
+
+ struct flock flk, svflk;
+ int retVal;
+ int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_TRUNC | O_RDWR, S_IRWXU);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(fd, 0);
+
+ flk.l_type = F_WRLCK;
+ flk.l_start = 0;
+ flk.l_whence = SEEK_SET;
+ flk.l_len = 0;
+
+ // copy flk into svflk
+ svflk = flk;
+
+ retVal = LIBC_NAMESPACE::fcntl(fd, F_GETLK, &svflk);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(retVal, -1);
+ ASSERT_NE((int)flk.l_type, F_RDLCK); // File should not be read locked.
+
+ retVal = LIBC_NAMESPACE::fcntl(fd, F_SETLK, &svflk);
+ ASSERT_ERRNO_SUCCESS();
+ ASSERT_GT(retVal, -1);
+
+ ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/89507
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