tcgetattr函数的实现（glibc）

/* Copyright (C) 1992-2014 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  <http://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 (fd, termios_p)

34 int fd;

35  structtermios *termios_p;

36 {

37 struct __kernel_termios k_termios;

38 int retval;

39 

40  retval =INLINE_SYSCALL (ioctl, 3, fd,TCGETS, &k_termios);

41 

42 if (__glibc_likely (retval == 0))

43  {

44  termios_p->c_iflag = k_termios.c_iflag;

45  termios_p->c_oflag = k_termios.c_oflag;

46  termios_p->c_cflag = k_termios.c_cflag;

47  termios_p->c_lflag = k_termios.c_lflag;

48  termios_p->c_line = k_termios.c_line;

49 #ifdef _HAVE_STRUCT_TERMIOS_C_ISPEED

50 # ifdef _HAVE_C_ISPEED

51  termios_p->c_ispeed = k_termios.c_ispeed;

52 # else

53  termios_p->c_ispeed = k_termios.c_cflag & (CBAUD | CBAUDEX);

54 # endif

55 #endif

56 #ifdef _HAVE_STRUCT_TERMIOS_C_OSPEED

57 # ifdef _HAVE_C_OSPEED

58  termios_p->c_ospeed = k_termios.c_ospeed;

59 # else

60  termios_p->c_ospeed = k_termios.c_cflag & (CBAUD | CBAUDEX);

61 # endif

62 #endif

63 if (sizeof (cc_t) == 1 ||_POSIX_VDISABLE == 0

64  || (unsigned char)_POSIX_VDISABLE == (unsigned char) -1)

65 memset (__mempcpy (&termios_p->c_cc[0], &k_termios.c_cc[0],

66 __KERNEL_NCCS * sizeof (cc_t)),

67 _POSIX_VDISABLE, (NCCS -__KERNEL_NCCS) * sizeof (cc_t));

68 else

69  {

70 memcpy (&termios_p->c_cc[0], &k_termios.c_cc[0],

71 __KERNEL_NCCS * sizeof (cc_t));

72 

73 for (size_t cnt = __KERNEL_NCCS; cnt < NCCS; ++cnt)

74  termios_p->c_cc[cnt] = _POSIX_VDISABLE;

75  }

76  }

77 

78 return retval;

79 }

80 

81 weak_alias (__tcgetattr,tcgetattr)