Merge remote-tracking branch 'remotes/vivier/tags/trivial-branch-for-6.2-pull-request...
[qemu.git] / linux-user / semihost.c
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 <termios.h>
17
18 int qemu_semihosting_console_outs(CPUArchState *env, target_ulong addr)
19 {
20 int len = target_strlen(addr);
21 void *s;
22 if (len < 0){
23 qemu_log_mask(LOG_GUEST_ERROR,
24 "%s: passed inaccessible address " TARGET_FMT_lx,
25 __func__, addr);
26 return 0;
27 }
28 s = lock_user(VERIFY_READ, addr, (long)(len + 1), 1);
29 g_assert(s); /* target_strlen has already verified this will work */
30 len = write(STDERR_FILENO, s, len);
31 unlock_user(s, addr, 0);
32 return len;
33 }
34
35 void qemu_semihosting_console_outc(CPUArchState *env, target_ulong addr)
36 {
37 char c;
38
39 if (get_user_u8(c, addr)) {
40 qemu_log_mask(LOG_GUEST_ERROR,
41 "%s: passed inaccessible address " TARGET_FMT_lx,
42 __func__, addr);
43 } else {
44 if (write(STDERR_FILENO, &c, 1) != 1) {
45 qemu_log_mask(LOG_UNIMP, "%s: unexpected write to stdout failure",
46 __func__);
47 }
48 }
49 }
50
51 /*
52 * For linux-user we can safely block. However as we want to return as
53 * soon as a character is read we need to tweak the termio to disable
54 * line buffering. We restore the old mode afterwards in case the
55 * program is expecting more normal behaviour. This is slow but
56 * nothing using semihosting console reading is expecting to be fast.
57 */
58 target_ulong qemu_semihosting_console_inc(CPUArchState *env)
59 {
60 uint8_t c;
61 struct termios old_tio, new_tio;
62
63 /* Disable line-buffering and echo */
64 tcgetattr(STDIN_FILENO, &old_tio);
65 new_tio = old_tio;
66 new_tio.c_lflag &= (~ICANON & ~ECHO);
67 tcsetattr(STDIN_FILENO, TCSANOW, &new_tio);
68
69 c = getchar();
70
71 /* restore config */
72 tcsetattr(STDIN_FILENO, TCSANOW, &old_tio);
73
74 return (target_ulong) c;
75 }