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Reland: [libc] implement ioctl #85890 #90317

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@llvmbot llvmbot added the libc label Apr 27, 2024
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llvmbot commented Apr 27, 2024

@llvm/pr-subscribers-libc

Author: Nhat Nguyen (changkhothuychung)

Changes

Full diff: https://github.com/llvm/llvm-project/pull/90317.diff

13 Files Affected:

  • (modified) libc/config/linux/aarch64/entrypoints.txt (+3)
  • (modified) libc/config/linux/riscv/entrypoints.txt (+3)
  • (modified) libc/config/linux/x86_64/entrypoints.txt (+3)
  • (modified) libc/spec/linux.td (+18)
  • (modified) libc/src/sys/CMakeLists.txt (+1)
  • (added) libc/src/sys/ioctl/CMakeLists.txt (+12)
  • (added) libc/src/sys/ioctl/ioctl.h (+17)
  • (added) libc/src/sys/ioctl/linux/CMakeLists.txt (+13)
  • (added) libc/src/sys/ioctl/linux/ioctl.cpp (+39)
  • (modified) libc/test/src/sys/CMakeLists.txt (+5-3)
  • (added) libc/test/src/sys/ioctl/CMakeLists.txt (+3)
  • (added) libc/test/src/sys/ioctl/linux/CMakeLists.txt (+13)
  • (added) libc/test/src/sys/ioctl/linux/ioctl_test.cpp (+27)
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 78da7f0b334b1fe..b5f8454081c8984 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -204,6 +204,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     #libc.src.stdio.scanf
     #libc.src.stdio.fscanf
 
+    # sys/ioctl.h entrypoints
+    libc.src.sys.ioctl.ioctl
+
     # sys/mman.h entrypoints
     libc.src.sys.mman.madvise
     libc.src.sys.mman.mmap
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index 5aae4e246cfb3c2..da9f0a9fb5b506d 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -209,6 +209,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.scanf
     libc.src.stdio.fscanf
 
+    # sys/ioctl.h entrypoints
+    libc.src.sys.ioctl.ioctl
+
     # sys/mman.h entrypoints
     libc.src.sys.mman.madvise
     libc.src.sys.mman.mmap
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 5b428e51aee6206..923946a75a24f59 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -221,6 +221,9 @@ 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.mmap
diff --git a/libc/spec/linux.td b/libc/spec/linux.td
index f91f55ddac78466..6e9b64f5a6b4aff 100644
--- a/libc/spec/linux.td
+++ b/libc/spec/linux.td
@@ -79,6 +79,24 @@ def Linux : StandardSpec<"Linux"> {
       []  // Functions
   >;
 
+  HeaderSpec SysIoctl = HeaderSpec<
+      "sys/ioctl.h",
+      [Macro<"MAP_ANONYMOUS">],
+      [], // Types
+      [], // Enumerations
+      [
+        FunctionSpec<
+            "ioctl",
+            RetValSpec<IntType>,
+            [
+              ArgSpec<IntType>,
+              ArgSpec<UnsignedLongType>,
+              ArgSpec<VoidPtr>,
+            ]
+        >,
+      ]  // Functions
+  >;
+
   HeaderSpec SysMMan = HeaderSpec<
       "sys/mman.h",
       [Macro<"MAP_ANONYMOUS">],
diff --git a/libc/src/sys/CMakeLists.txt b/libc/src/sys/CMakeLists.txt
index adc666b94202f7d..ac54df35284a7b8 100644
--- a/libc/src/sys/CMakeLists.txt
+++ b/libc/src/sys/CMakeLists.txt
@@ -1,5 +1,6 @@
 add_subdirectory(auxv)
 add_subdirectory(epoll)
+add_subdirectory(ioctl)
 add_subdirectory(mman)
 add_subdirectory(random)
 add_subdirectory(resource)
diff --git a/libc/src/sys/ioctl/CMakeLists.txt b/libc/src/sys/ioctl/CMakeLists.txt
new file mode 100644
index 000000000000000..4b50c278c7871a8
--- /dev/null
+++ b/libc/src/sys/ioctl/CMakeLists.txt
@@ -0,0 +1,12 @@
+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 000000000000000..8365678276a4286
--- /dev/null
+++ b/libc/src/sys/ioctl/ioctl.h
@@ -0,0 +1,17 @@
+//===-- Implementation header for mmap function -----------------*- 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
+namespace LIBC_NAMESPACE {
+
+int ioctl(int fd, unsigned long request, ...);
+
+} // namespace LIBC_NAMESPACE
+
+#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 000000000000000..8a23505d4e9d19e
--- /dev/null
+++ b/libc/src/sys/ioctl/linux/CMakeLists.txt
@@ -0,0 +1,13 @@
+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 000000000000000..c743cf7a9dd5969
--- /dev/null
+++ b/libc/src/sys/ioctl/linux/ioctl.cpp
@@ -0,0 +1,39 @@
+//===---------- Linux implementation of the POSIX 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 {
+
+// This function is currently linux only. It has to be refactored suitably if
+// madvise is to be supported on non-linux operating systems also.
+LLVM_LIBC_FUNCTION(int, ioctl, (int fd, unsigned long request, ...)) {
+  va_list ptr_to_memory;
+  va_start(ptr_to_memory, request);
+  va_arg(ptr_to_memory, void *);
+  int ret =
+      LIBC_NAMESPACE::syscall_impl<int>(SYS_ioctl, fd, request, ptr_to_memory);
+  va_end(ptr_to_memory);
+
+  // A negative return value indicates an error with the magnitude of the
+  // value being the error code.
+  if (ret < 0) {
+    libc_errno = -ret;
+    return -1;
+  }
+
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/test/src/sys/CMakeLists.txt b/libc/test/src/sys/CMakeLists.txt
index dc0aa8bf7b75dc1..b58644e60f57872 100644
--- a/libc/test/src/sys/CMakeLists.txt
+++ b/libc/test/src/sys/CMakeLists.txt
@@ -1,4 +1,8 @@
+add_subdirectory(auxv)
+add_subdirectory(epoll)
+add_subdirectory(ioctl)
 add_subdirectory(mman)
+add_subdirectory(prctl)
 add_subdirectory(random)
 add_subdirectory(resource)
 add_subdirectory(select)
@@ -8,6 +12,4 @@ add_subdirectory(stat)
 add_subdirectory(statvfs)
 add_subdirectory(utsname)
 add_subdirectory(wait)
-add_subdirectory(prctl)
-add_subdirectory(auxv)
-add_subdirectory(epoll)
+
diff --git a/libc/test/src/sys/ioctl/CMakeLists.txt b/libc/test/src/sys/ioctl/CMakeLists.txt
new file mode 100644
index 000000000000000..b4bbe81c92ff2eb
--- /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 000000000000000..aa1bffec16bd672
--- /dev/null
+++ b/libc/test/src/sys/ioctl/linux/CMakeLists.txt
@@ -0,0 +1,13 @@
+add_custom_target(libc_sys_ioctl_unittests)
+
+add_libc_unittest(
+  ioctl_test
+  SUITE
+    libc_sys_ioctl_unittests
+  SRCS
+    ioctl_test.cpp
+  DEPENDS
+    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 000000000000000..4fc76d1b3c1842c
--- /dev/null
+++ b/libc/test/src/sys/ioctl/linux/ioctl_test.cpp
@@ -0,0 +1,27 @@
+//===-- 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/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/errno/libc_errno.h"
+#include "src/sys/ioctl/ioctl.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/LibcTest.h"
+#include "test/UnitTest/Test.h"
+
+#include <sys/syscall.h>
+#include <unistd.h>
+
+using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
+using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+
+TEST(LlvmLibcIoctlTest, InvalidFileDescriptor) {
+  int fd = 10;
+  unsigned long request = 10;
+  int res = LIBC_NAMESPACE::ioctl(fd, request, NULL);
+  EXPECT_THAT(res, Fails(EBADF, -1));
+}

@changkhothuychung
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@nickdesaulniers nick
can u take a look when you have time? thanks.

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Nick's busy for a couple weeks so I'll be reviewing this patch.

namespace LIBC_NAMESPACE {

// This function is currently linux only. It has to be refactored suitably if
// madvise is to be supported on non-linux operating systems also.
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nit: update comment to refer to the correct function instead of madvise.

TEST(LlvmLibcIoctlTest, InvalidFileDescriptor) {
int fd = 10;
unsigned long request = 10;
int res = LIBC_NAMESPACE::ioctl(fd, request, NULL);
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please add a test that succeeds as well.

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@michaelrj-google do you have an idea what test can I use to always guarantee success ? From the other PR @nickdesaulniers nick
told me I dont need to test for this syscall because it is a linux syscall, and the current test file is fine. I tried a test that I expect to succeeds in the PR but that seems to fail in the CI.

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Perhaps FS_IOC_GETFLAGS.
https://man7.org/linux/man-pages/man2/ioctl_iflags.2.html

That is used as the example for ioctl in Michael Kerrisk's The Linux Programming Interface page 308.

int fd = open("/dev/null", O_RDWR);
int data;
int res = LIBC_NAMESPACE::ioctl(fd, FIONREAD, &data);
EXPECT_THAT(res, Succeeds());
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@nickdesaulniers nickdesaulniers May 20, 2024

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From the presubmit build failure:

ioctl_test.cpp:35: FAILURE
Failed to match res against Succeeds().
Expected return value to be equal to 0 but got -1.
Expected errno to be equal to "Success" but got "Inappropriate ioctl for device".

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I applied FS_IOC_GETFLAGS but it seems the same error is still there

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it looks like the error In appropriate ioctl for device is for the case the test wants to connect to terminal but there is no terminal on the CI.

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This is perhaps related to the usage of /dev/null as the input file. Perhaps we need to create a new file and run the test on that.

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$ lsattr /dev/null
lsattr: Operation not supported While reading flags on /dev/null

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See how libc/test/src/stdio/ tests create temp files.

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looks like it works now

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make sure to close the file

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@nickdesaulniers nick
do u know why I am getting error undefined symbol to libc_namspace::open() and close()?

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Is that a linkage failure? Then that would be a missing dependency in cmake for the test.

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Is this ready for re-review, or?

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Is this ready for re-review, or?

Yes, this is ready for review now! Thanks.

@jhuber6 jhuber6 changed the title Reland: [libc] implement ioctl ([libc] implement ioctl #85890) Reland: [libc] implement ioctl #85890 Jul 3, 2024
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4 participants