[libc] Add termios.h and the implementation of functions declared in it.

Reviewed By: lntue, michaelrj

Differential Revision: https://reviews.llvm.org/D136143

1 files changed, 33 insertions, 0 deletions

diff --git a/libc/src/termios/linux/tcsendbreak.cpp b/libc/src/termios/linux/tcsendbreak.cpp
new file mode 100644
index 000000000000..18aeba6b8098
--- /dev/null
+++ b/libc/src/termios/linux/tcsendbreak.cpp
@@ -0,0 +1,33 @@
+//===-- Linux implementation of tcsendbreak -------------------------------===//
+//
+// 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/termios/tcsendbreak.h"
+
+#include "src/__support/OSUtil/syscall.h"
+#include "src/__support/common.h"
+
+#include <asm/ioctls.h> // Safe to include without the risk of name pollution.
+#include <errno.h>
+#include <sys/syscall.h> // For syscall numbers
+#include <termios.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(pid_t, tcsendbreak, (int fd, int /* unused duration */)) {
+  // POSIX leaves the behavior for non-zero duration implementation dependent.
+  // Which means that the behavior can be the same as it is when duration is
+  // zero. So, we just pass zero to the syscall.
+  long ret = __llvm_libc::syscall_impl(SYS_ioctl, fd, TCSBRK, 0);
+  if (ret < 0) {
+    errno = -ret;
+    return -1;
+  }
+  return 0;
+}
+
+} // namespace __llvm_libc