sysdeps/unix/sysv/linux/tcgetattr.c

   1 /* Copyright (C) 1992-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <string.h>
  20 #include <termios.h>
  21 #include <unistd.h>
  22 #include <sys/ioctl.h>
  23 #include <sys/types.h>
  24 #include <sysdep.h>
  25
  26 /* The difference here is that the termios structure used in the
  27    kernel is not the same as we use in the libc.  Therefore we must
  28    translate it here.  */
  29 #include <kernel_termios.h>
  30
  31 /* Put the state of FD into *TERMIOS_P.  */
  32 int
  33 __tcgetattr (int fd, struct termios *termios_p)
  34 {
  35   struct __kernel_termios k_termios;
  36   int retval;
  37
  38   retval = INLINE_SYSCALL (ioctl, 3, fd, TCGETS, &k_termios);
  39
  40   if (__glibc_likely (retval == 0))
  41     {
  42       termios_p->c_iflag = k_termios.c_iflag;
  43       termios_p->c_oflag = k_termios.c_oflag;
  44       termios_p->c_cflag = k_termios.c_cflag;
  45       termios_p->c_lflag = k_termios.c_lflag;
  46       termios_p->c_line = k_termios.c_line;
  47 #if _HAVE_STRUCT_TERMIOS_C_ISPEED
  48 # if _HAVE_C_ISPEED
  49       termios_p->c_ispeed = k_termios.c_ispeed;
  50 # else
  51       termios_p->c_ispeed = k_termios.c_cflag & (CBAUD | CBAUDEX);
  52 # endif
  53 #endif
  54 #if _HAVE_STRUCT_TERMIOS_C_OSPEED
  55 # if _HAVE_C_OSPEED
  56       termios_p->c_ospeed = k_termios.c_ospeed;
  57 # else
  58       termios_p->c_ospeed = k_termios.c_cflag & (CBAUD | CBAUDEX);
  59 # endif
  60 #endif
  61       if (sizeof (cc_t) == 1 || _POSIX_VDISABLE == 0
  62           || (unsigned char) _POSIX_VDISABLE == (unsigned char) -1)
  63         memset (__mempcpy (&termios_p->c_cc[0], &k_termios.c_cc[0],
  64                            __KERNEL_NCCS * sizeof (cc_t)),
  65                 _POSIX_VDISABLE, (NCCS - __KERNEL_NCCS) * sizeof (cc_t));
  66       else
  67         {
  68           memcpy (&termios_p->c_cc[0], &k_termios.c_cc[0],
  69                   __KERNEL_NCCS * sizeof (cc_t));
  70
  71           for (size_t cnt = __KERNEL_NCCS; cnt < NCCS; ++cnt)
  72             termios_p->c_cc[cnt] = _POSIX_VDISABLE;
  73         }
  74     }
  75
  76   return retval;
  77 }
  78
  79 libc_hidden_def (__tcgetattr)
  80 weak_alias (__tcgetattr, tcgetattr)