Skip to content

[libc] add ioctl #141393

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 16 commits into
base: main
Choose a base branch
from
Open

[libc] add ioctl #141393

wants to merge 16 commits into from

Conversation

cowtoolz
Copy link

@cowtoolz cowtoolz commented May 25, 2025

Closes #85275
Closes #90317
Updates #97191

Copy link

Thank you for submitting a Pull Request (PR) to the LLVM Project!

This PR will be automatically labeled and the relevant teams will be notified.

If you wish to, you can add reviewers by using the "Reviewers" section on this page.

If this is not working for you, it is probably because you do not have write permissions for the repository. In which case you can instead tag reviewers by name in a comment by using @ followed by their GitHub username.

If you have received no comments on your PR for a week, you can request a review by "ping"ing the PR by adding a comment “Ping”. The common courtesy "ping" rate is once a week. Please remember that you are asking for valuable time from other developers.

If you have further questions, they may be answered by the LLVM GitHub User Guide.

You can also ask questions in a comment on this PR, on the LLVM Discord or on the forums.

@llvmbot llvmbot added the libc label May 25, 2025
@llvmbot
Copy link
Member

llvmbot commented May 25, 2025

@llvm/pr-subscribers-libc

Author: ~cowtools (cowtoolz)

Changes

Closes #85275
Closes #90317


Full diff: https://github.com/llvm/llvm-project/pull/141393.diff

13 Files Affected:

  • (modified) libc/config/linux/aarch64/entrypoints.txt (+3)
  • (modified) libc/config/linux/arm/entrypoints.txt (+3)
  • (modified) libc/config/linux/riscv/entrypoints.txt (+3)
  • (modified) libc/config/linux/x86_64/entrypoints.txt (+3)
  • (modified) libc/src/sys/CMakeLists.txt (+1)
  • (added) libc/src/sys/ioctl/CMakeLists.txt (+10)
  • (added) libc/src/sys/ioctl/ioctl.h (+21)
  • (added) libc/src/sys/ioctl/linux/CMakeLists.txt (+12)
  • (added) libc/src/sys/ioctl/linux/ioctl.cpp (+40)
  • (modified) libc/test/src/sys/CMakeLists.txt (+1)
  • (added) libc/test/src/sys/ioctl/CMakeLists.txt (+3)
  • (added) libc/test/src/sys/ioctl/linux/CMakeLists.txt (+14)
  • (added) libc/test/src/sys/ioctl/linux/ioctl_test.cpp (+34)
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 520046f768b5d..fcf1278eae723 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -245,6 +245,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     # https://github.com/llvm/llvm-project/issues/80060
     # libc.src.sys.epoll.epoll_pwait2
 
+    # sys/ioctl.h entrypoints
+    libc.src.sys.ioctl.ioctl
+
     # sys/mman.h entrypoints
     libc.src.sys.mman.madvise
     libc.src.sys.mman.mincore
diff --git a/libc/config/linux/arm/entrypoints.txt b/libc/config/linux/arm/entrypoints.txt
index 7432a7e912e81..1161ae260be2e 100644
--- a/libc/config/linux/arm/entrypoints.txt
+++ b/libc/config/linux/arm/entrypoints.txt
@@ -172,6 +172,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.free
     libc.src.stdlib.malloc
 
+    # sys/ioctl.h entrypoints
+    libc.src.sys.ioctl.ioctl
+
     # sys/mman.h entrypoints
     libc.src.sys.mman.mmap
     libc.src.sys.mman.munmap
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index 0b645a2d2fb8b..050fc2672a57e 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -246,6 +246,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     # https://github.com/llvm/llvm-project/issues/80060
     # libc.src.sys.epoll.epoll_pwait2
 
+    # sys/ioctl.h entrypoints
+    libc.src.sys.ioctl.ioctl
+
     # sys/mman.h entrypoints
     libc.src.sys.mman.madvise
     libc.src.sys.mman.mincore
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 9f447dd0d35d2..07ebf51f70774 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -246,6 +246,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     # https://github.com/llvm/llvm-project/issues/80060
     # libc.src.sys.epoll.epoll_pwait2
 
+    # sys/ioctl.h entrypoints
+    libc.src.sys.ioctl.ioctl
+
     # sys/mman.h entrypoints
     libc.src.sys.mman.madvise
     libc.src.sys.mman.mincore
diff --git a/libc/src/sys/CMakeLists.txt b/libc/src/sys/CMakeLists.txt
index 9a73b80d35d2f..0fa11e9eee696 100644
--- a/libc/src/sys/CMakeLists.txt
+++ b/libc/src/sys/CMakeLists.txt
@@ -13,3 +13,4 @@ add_subdirectory(utsname)
 add_subdirectory(wait)
 add_subdirectory(prctl)
 add_subdirectory(uio)
+add_subdirectory(ioctl)
diff --git a/libc/src/sys/ioctl/CMakeLists.txt b/libc/src/sys/ioctl/CMakeLists.txt
new file mode 100644
index 0000000000000..099a1b96389fc
--- /dev/null
+++ b/libc/src/sys/ioctl/CMakeLists.txt
@@ -0,0 +1,10 @@
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+endif()
+
+add_entrypoint_object(
+  ioctl
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.ioctl
+)
diff --git a/libc/src/sys/ioctl/ioctl.h b/libc/src/sys/ioctl/ioctl.h
new file mode 100644
index 0000000000000..91d6bb7f7abe7
--- /dev/null
+++ b/libc/src/sys/ioctl/ioctl.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for ioctl ---------------------------*-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_SYS_IOCTL_IOCTL_H
+#define LLVM_LIBC_SRC_SYS_IOCTL_IOCTL_H
+
+#include "src/__support/macros/config.h"
+#include <sys/ioctl.h>
+
+namespace LIBC_NAMESPACE_DECL {
+
+int ioctl(int fd, unsigned long request, ...);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_SYS_IOCTL_IOCTL_H
diff --git a/libc/src/sys/ioctl/linux/CMakeLists.txt b/libc/src/sys/ioctl/linux/CMakeLists.txt
new file mode 100644
index 0000000000000..876f35aaee66c
--- /dev/null
+++ b/libc/src/sys/ioctl/linux/CMakeLists.txt
@@ -0,0 +1,12 @@
+add_entrypoint_object(
+  ioctl
+  SRCS
+    ioctl.cpp
+  HDRS
+    ../ioctl.h
+  DEPENDS
+    libc.include.sys_ioctl
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
+)
diff --git a/libc/src/sys/ioctl/linux/ioctl.cpp b/libc/src/sys/ioctl/linux/ioctl.cpp
new file mode 100644
index 0000000000000..898385027105c
--- /dev/null
+++ b/libc/src/sys/ioctl/linux/ioctl.cpp
@@ -0,0 +1,40 @@
+//===---------- Linux implementation of the ioctl function ----------------===//
+//
+// 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/sys/ioctl/ioctl.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 LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, ioctl, (int fd, unsigned long request, ...)) {
+  va_list vargs;
+  va_start(vargs, request);
+  void *data_pointer = va_arg(vargs, void *);
+  int ret =
+      LIBC_NAMESPACE::syscall_impl<int>(SYS_ioctl, fd, request, data_pointer);
+  va_end(vargs);
+
+  // From `man ioctl`:
+  // "Usually, on success zero is returned.  A few ioctl() operations
+  // use the return value as an output parameter and return a
+  // nonnegative value on success.  On error, -1 is returned, and errno
+  // is set to indicate the error."
+  if (ret < 0) {
+    libc_errno = -ret;
+    return -1;
+  }
+
+  return ret;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/src/sys/CMakeLists.txt b/libc/test/src/sys/CMakeLists.txt
index 224cc7905ad31..13bf91eef04be 100644
--- a/libc/test/src/sys/CMakeLists.txt
+++ b/libc/test/src/sys/CMakeLists.txt
@@ -13,3 +13,4 @@ add_subdirectory(auxv)
 add_subdirectory(epoll)
 add_subdirectory(uio)
 add_subdirectory(time)
+add_subdirectory(ioctl)
diff --git a/libc/test/src/sys/ioctl/CMakeLists.txt b/libc/test/src/sys/ioctl/CMakeLists.txt
new file mode 100644
index 0000000000000..b4bbe81c92ff2
--- /dev/null
+++ b/libc/test/src/sys/ioctl/CMakeLists.txt
@@ -0,0 +1,3 @@
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+  add_subdirectory(${LIBC_TARGET_OS})
+endif()
diff --git a/libc/test/src/sys/ioctl/linux/CMakeLists.txt b/libc/test/src/sys/ioctl/linux/CMakeLists.txt
new file mode 100644
index 0000000000000..1466453fe08aa
--- /dev/null
+++ b/libc/test/src/sys/ioctl/linux/CMakeLists.txt
@@ -0,0 +1,14 @@
+add_custom_target(libc_sys_ioctl_unittests)
+
+add_libc_unittest(
+  ioctl_test
+  SUITE
+    libc_sys_ioctl_unittests
+  SRCS
+    ioctl_test.cpp
+  DEPENDS
+    libc.include.sys_ioctl
+    libc.include.sys_filio
+    libc.src.sys.ioctl.ioctl
+    libc.src.errno.errno
+)
diff --git a/libc/test/src/sys/ioctl/linux/ioctl_test.cpp b/libc/test/src/sys/ioctl/linux/ioctl_test.cpp
new file mode 100644
index 0000000000000..1752db8a57ce7
--- /dev/null
+++ b/libc/test/src/sys/ioctl/linux/ioctl_test.cpp
@@ -0,0 +1,34 @@
+//===-- Unittests for ioctl -----------------------------------------------===//
+//
+// 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/sys/ioctl/ioctl.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include <sys/filio.h>
+#include <sys/ioctl.h>
+
+using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
+using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+
+TEST(LlvmLibcSysIoctlTest, StdinFIONREAD) {
+  LIBC_NAMESPACE::libc_errno = 0;
+
+  // FIONREAD reports the number of readable bytes for fd
+  int bytes;
+  int ret = LIBC_NAMESPACE::ioctl(0, FIONREAD, &bytes);
+  ASSERT_ERRNO_SUCCESS();
+}
+
+TEST(LlvmLibcSysIoctlTest, InvalidCommandENOTTY) {
+  LIBC_NAMESPACE::libc_errno = 0;
+
+  // 0xDEADBEEF is just a random nonexistent command;
+  // calling this should always fail with ENOTTY
+  int ret = LIBC_NAMESPACE::ioctl(3, 0xDEADBEEF, NULL);
+  ASSERT_TRUE(ret == -1 && errno == ENOTTY);
+}

@cowtoolz
Copy link
Author

cowtoolz commented May 25, 2025

Via #85275

I also see open coded calls to ioctl in:

* src/unistd/linux/isatty.cpp
* src/termios/linux/tcgetattr.cpp
* src/termios/linux/tcsendbreak.cpp 
* src/termios/linux/tcgetsid.cpp
* src/termios/linux/tcdrain.cpp
* src/termios/linux/tcsetattr.cpp
* src/termios/linux/tcflush.cpp
* src/termios/linux/tcflow.cpp

I assume once ioctl is implemented, all of the above open coded calls should be replaced with the call to our internal wrapper.

I've already made these changes, should these be included in this PR?

@cowtoolz cowtoolz requested a review from jhuber6 May 25, 2025 16:18
cowtoolz and others added 2 commits May 25, 2025 12:23
Copy link
Contributor

@michaelrj-google michaelrj-google left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This is a good start, but the test needs some cleanup

Co-authored-by: Michael Jones <michaelrj@google.com>
@michaelrj-google
Copy link
Contributor

The code changes look good to me, but the premerge checks are failing. The error numbers are 25 (ENOTTY) and 9 (EBADF), so it's probably to do with running this on a buildbot instead of locally. It might be best to use open to create a file descriptor instead of using 0 and 3.

@cowtoolz cowtoolz requested a review from lntue May 30, 2025 17:16
Copy link
Contributor

@michaelrj-google michaelrj-google left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

A few more comments, looks like it's getting close to done

constexpr int TEST_MSG_SIZE = sizeof(TEST_MSG) - 1;
auto TEST_FILE = libc_make_test_file_path(TEST_FILE_NAME);
int new_test_file_fd =
LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_WRONLY, 0644);
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The 0644 can be replaced by S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH to make it more clear that's the file permissions being set.

LIBC_NAMESPACE::libc_errno = 0;

// Setup the test file
constexpr const char *TEST_FILE_NAME = "testdata/ioctl.test";
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Please remove the testdata subfolder so we can simplify the cmake

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
Projects
None yet
Development

Successfully merging this pull request may close these issues.

[libc] implement ioctl
5 participants