LXR qemu/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 "user-internals.h"
  17#include <termios.h>
  18
  19int qemu_semihosting_console_outs(CPUArchState *env, target_ulong addr)
  20{
  21    int len = target_strlen(addr);
  22    void *s;
  23    if (len < 0){
  24       qemu_log_mask(LOG_GUEST_ERROR,
  25                     "%s: passed inaccessible address " TARGET_FMT_lx,
  26                     __func__, addr);
  27       return 0;
  28    }
  29    s = lock_user(VERIFY_READ, addr, (long)(len + 1), 1);
  30    g_assert(s);  /* target_strlen has already verified this will work */
  31    len = write(STDERR_FILENO, s, len);
  32    unlock_user(s, addr, 0);
  33    return len;
  34}
  35
  36void qemu_semihosting_console_outc(CPUArchState *env, target_ulong addr)
  37{
  38    char c;
  39
  40    if (get_user_u8(c, addr)) {
  41        qemu_log_mask(LOG_GUEST_ERROR,
  42                      "%s: passed inaccessible address " TARGET_FMT_lx,
  43                      __func__, addr);
  44    } else {
  45        if (write(STDERR_FILENO, &c, 1) != 1) {
  46            qemu_log_mask(LOG_UNIMP, "%s: unexpected write to stdout failure",
  47                          __func__);
  48        }
  49    }
  50}
  51
  52/*
  53 * For linux-user we can safely block. However as we want to return as
  54 * soon as a character is read we need to tweak the termio to disable
  55 * line buffering. We restore the old mode afterwards in case the
  56 * program is expecting more normal behaviour. This is slow but
  57 * nothing using semihosting console reading is expecting to be fast.
  58 */
  59target_ulong qemu_semihosting_console_inc(CPUArchState *env)
  60{
  61    uint8_t c;
  62    struct termios old_tio, new_tio;
  63
  64    /* Disable line-buffering and echo */
  65    tcgetattr(STDIN_FILENO, &old_tio);
  66    new_tio = old_tio;
  67    new_tio.c_lflag &= (~ICANON & ~ECHO);
  68    tcsetattr(STDIN_FILENO, TCSANOW, &new_tio);
  69
  70    c = getchar();
  71
  72    /* restore config */
  73    tcsetattr(STDIN_FILENO, TCSANOW, &old_tio);
  74
  75    return (target_ulong) c;
  76}
  77