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qemu/linux-user/semihost.c

51 lines
1.4 KiB
C

/*
* ARM Compatible Semihosting Console Support.
*
* Copyright (c) 2019 Linaro Ltd
*
* Currently ARM and RISC-V are unique in having support for
* semihosting support in linux-user. So for now we implement the
* common console API but just for arm and risc-v linux-user.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "qemu/osdep.h"
#include "semihosting/console.h"
#include "qemu.h"
#include "user-internals.h"
#include <termios.h>
/*
* For linux-user we can safely block. However as we want to return as
* soon as a character is read we need to tweak the termio to disable
* line buffering. We restore the old mode afterwards in case the
* program is expecting more normal behaviour. This is slow but
* nothing using semihosting console reading is expecting to be fast.
*/
int qemu_semihosting_console_read(CPUState *cs, void *buf, int len)
{
int ret;
struct termios old_tio, new_tio;
/* Disable line-buffering and echo */
tcgetattr(STDIN_FILENO, &old_tio);
new_tio = old_tio;
new_tio.c_lflag &= (~ICANON & ~ECHO);
new_tio.c_cc[VMIN] = 1;
new_tio.c_cc[VTIME] = 0;
tcsetattr(STDIN_FILENO, TCSANOW, &new_tio);
ret = fread(buf, 1, len, stdin);
/* restore config */
tcsetattr(STDIN_FILENO, TCSANOW, &old_tio);
return ret;
}
int qemu_semihosting_console_write(void *buf, int len)
{
return fwrite(buf, 1, len, stderr);
}