libc/src/termios/linux/tcsetattr.cpp

   1 //===-- Linux implementation of tcsetattr ---------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "src/termios/tcsetattr.h"
  10 #include "kernel_termios.h"
  11
  12 #include "src/__support/OSUtil/syscall.h"
  13 #include "src/__support/common.h"
  14 #include "src/errno/libc_errno.h"
  15
  16 #include <asm/ioctls.h> // Safe to include without the risk of name pollution.
  17 #include <sys/syscall.h> // For syscall numbers
  18 #include <termios.h>
  19
  20 namespace LIBC_NAMESPACE {
  21
  22 LLVM_LIBC_FUNCTION(int, tcsetattr,
  23                    (int fd, int actions, const struct termios *t)) {
  24   struct kernel_termios kt;
  25   long cmd;
  26
  27   switch (actions) {
  28   case TCSANOW:
  29     cmd = TCSETS;
  30     break;
  31   case TCSADRAIN:
  32     cmd = TCSETSW;
  33     break;
  34   case TCSAFLUSH:
  35     cmd = TCSETSF;
  36     break;
  37   default:
  38     libc_errno = EINVAL;
  39     return -1;
  40   }
  41
  42   kt.c_iflag = t->c_iflag;
  43   kt.c_oflag = t->c_oflag;
  44   kt.c_cflag = t->c_cflag;
  45   kt.c_lflag = t->c_lflag;
  46   size_t nccs = KERNEL_NCCS <= NCCS ? KERNEL_NCCS : NCCS;
  47   for (size_t i = 0; i < nccs; ++i)
  48     kt.c_cc[i] = t->c_cc[i];
  49   if (nccs < KERNEL_NCCS) {
  50     for (size_t i = nccs; i < KERNEL_NCCS; ++i)
  51       kt.c_cc[i] = 0;
  52   }
  53
  54   int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_ioctl, fd, cmd, &kt);
  55   if (ret < 0) {
  56     libc_errno = -ret;
  57     return -1;
  58   }
  59   return 0;
  60 }
  61
  62 } // namespace LIBC_NAMESPACE