1 /*
2 * ARM Compatible Semihosting Console Support.
3 *
4 * Copyright (c) 2019 Linaro Ltd
5 *
6 * Currently ARM and RISC-V are unique in having support for
7 * semihosting support in linux-user. So for now we implement the
8 * common console API but just for arm and risc-v linux-user.
9 *
10 * SPDX-License-Identifier: GPL-2.0-or-later
11 */
12
13 #include "qemu/osdep.h"
14 #include "semihosting/console.h"
15 #include "qemu.h"
16 #include "user-internals.h"
17 #include <termios.h>
18
19 /*
20 * For linux-user we can safely block. However as we want to return as
21 * soon as a character is read we need to tweak the termio to disable
22 * line buffering. We restore the old mode afterwards in case the
23 * program is expecting more normal behaviour. This is slow but
24 * nothing using semihosting console reading is expecting to be fast.
25 */
qemu_semihosting_console_read(CPUState * cs,void * buf,int len)26 int qemu_semihosting_console_read(CPUState *cs, void *buf, int len)
27 {
28 int ret;
29 struct termios old_tio, new_tio;
30
31 /* Disable line-buffering and echo */
32 tcgetattr(STDIN_FILENO, &old_tio);
33 new_tio = old_tio;
34 new_tio.c_lflag &= (~ICANON & ~ECHO);
35 new_tio.c_cc[VMIN] = 1;
36 new_tio.c_cc[VTIME] = 0;
37 tcsetattr(STDIN_FILENO, TCSANOW, &new_tio);
38
39 ret = fread(buf, 1, len, stdin);
40
41 /* restore config */
42 tcsetattr(STDIN_FILENO, TCSANOW, &old_tio);
43
44 return ret;
45 }
46
qemu_semihosting_console_write(void * buf,int len)47 int qemu_semihosting_console_write(void *buf, int len)
48 {
49 return fwrite(buf, 1, len, stderr);
50 }
51