xref: /aosp_15_r20/external/llvm-libc/src/termios/linux/tcsetattr.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
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/__support/macros/config.h"
15 #include "src/errno/libc_errno.h"
16 
17 #include <asm/ioctls.h> // Safe to include without the risk of name pollution.
18 #include <sys/syscall.h> // For syscall numbers
19 #include <termios.h>
20 
21 namespace LIBC_NAMESPACE_DECL {
22 
23 LLVM_LIBC_FUNCTION(int, tcsetattr,
24                    (int fd, int actions, const struct termios *t)) {
25   struct kernel_termios kt;
26   long cmd;
27 
28   switch (actions) {
29   case TCSANOW:
30     cmd = TCSETS;
31     break;
32   case TCSADRAIN:
33     cmd = TCSETSW;
34     break;
35   case TCSAFLUSH:
36     cmd = TCSETSF;
37     break;
38   default:
39     libc_errno = EINVAL;
40     return -1;
41   }
42 
43   kt.c_iflag = t->c_iflag;
44   kt.c_oflag = t->c_oflag;
45   kt.c_cflag = t->c_cflag;
46   kt.c_lflag = t->c_lflag;
47   size_t nccs = KERNEL_NCCS <= NCCS ? KERNEL_NCCS : NCCS;
48   for (size_t i = 0; i < nccs; ++i)
49     kt.c_cc[i] = t->c_cc[i];
50   if (nccs < KERNEL_NCCS) {
51     for (size_t i = nccs; i < KERNEL_NCCS; ++i)
52       kt.c_cc[i] = 0;
53   }
54 
55   int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_ioctl, fd, cmd, &kt);
56   if (ret < 0) {
57     libc_errno = -ret;
58     return -1;
59   }
60   return 0;
61 }
62 
63 } // namespace LIBC_NAMESPACE_DECL
64