[libc-commits] [libc] [libc] implement ioctl (PR #85890)

[Nick Desaulniers via libc-commits]

nickdesaulniers wrote:

Here are the changes I needed to make to make this compile and run successfully.
```diff
diff --git a/libc/src/sys/ioctl/linux/ioctl.cpp b/libc/src/sys/ioctl/linux/ioctl.cpp
index 6c8ff54dc2ae..f2354bcabb9c 100644
--- a/libc/src/sys/ioctl/linux/ioctl.cpp
+++ b/libc/src/sys/ioctl/linux/ioctl.cpp
@@ -20,10 +20,10 @@ namespace LIBC_NAMESPACE {
 // 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, 1);
-  va_arg(ptr_to_memory, void *) int ret =
-      LIBC_NAMESPACE::syscall_impl<int>(SYS_ioctl, fd, request, ptr_to_memory);
+  va_start(ptr_to_memory, request);
+  va_arg(ptr_to_memory, void *);
   va_end(ptr_to_memory);
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_ioctl, fd, request, ptr_to_memory);
 
   // A negative return value indicates an error with the magnitude of the
   // value being the error code.
diff --git a/libc/test/src/sys/CMakeLists.txt b/libc/test/src/sys/CMakeLists.txt
index dc0aa8bf7b75..e80936514fc4 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 +12,3 @@ 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/linux/CMakeLists.txt b/libc/test/src/sys/ioctl/linux/CMakeLists.txt
index 93e68975c4e1..aa1bffec16bd 100644
--- a/libc/test/src/sys/ioctl/linux/CMakeLists.txt
+++ b/libc/test/src/sys/ioctl/linux/CMakeLists.txt
@@ -7,8 +7,7 @@ add_libc_unittest(
   SRCS
     ioctl_test.cpp
   DEPENDS
-    libc.include.sys_ioctl
+    libc.src.sys.ioctl.ioctl
     libc.src.errno.errno
-    libc.test.errno_setter_matcher
 )
 
diff --git a/libc/test/src/sys/ioctl/linux/ioctl_test.cpp b/libc/test/src/sys/ioctl/linux/ioctl_test.cpp
index 3de3eff3e8d4..4fc76d1b3c18 100644
--- a/libc/test/src/sys/ioctl/linux/ioctl_test.cpp
+++ b/libc/test/src/sys/ioctl/linux/ioctl_test.cpp
@@ -22,6 +22,6 @@ using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
 TEST(LlvmLibcIoctlTest, InvalidFileDescriptor) {
   int fd = 10;
   unsigned long request = 10;
-  int res = LIBC_NAMESPACE::ioctl(fd, 10, NULL);
+  int res = LIBC_NAMESPACE::ioctl(fd, request, NULL);
   EXPECT_THAT(res, Fails(EBADF, -1));
 }
```

Please open a new PR with:
1. `git revert 3c2feab7d152b7f161b4adaecef4ec81f038a23e`. Use "Reland: [libc] implement ioctl (#85890)" as the commit one line description and when opening the PR.
2. add the changes I described above on top as a distinct commit, which will make it easier for reviewers to see what's new.  Use `git clang-format HEAD~` to reformat it (since I did not)

Push that for review and tag us.

https://github.com/llvm/llvm-project/pull/85890