vl.c

/*
 * QEMU System Emulator
 * 
 * Copyright (c) 2003-2004 Fabrice Bellard
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include "vl.h"

#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <time.h>
#include <errno.h>
#include <sys/time.h>

#ifndef _WIN32
#include <sys/times.h>
#include <sys/wait.h>
#include <termios.h>
#include <sys/poll.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <dirent.h>
#ifdef _BSD
#include <sys/stat.h>
#ifndef __APPLE__
#include <libutil.h>
#endif
#else
#include <linux/if.h>
#include <linux/if_tun.h>
#include <pty.h>
#include <malloc.h>
#include <linux/rtc.h>
#endif
#endif

#if defined(CONFIG_SLIRP)
#include "libslirp.h"
#endif

#ifdef _WIN32
#include <malloc.h>
#include <sys/timeb.h>
#include <windows.h>
#define getopt_long_only getopt_long
#define memalign(align, size) malloc(size)
#endif

#ifdef CONFIG_SDL
#ifdef __APPLE__
#include <SDL/SDL.h>
#endif
#endif /* CONFIG_SDL */

#include "disas.h"

#include "exec-all.h"

//#define DO_TB_FLUSH

#define DEFAULT_NETWORK_SCRIPT "/etc/qemu-ifup"

//#define DEBUG_UNUSED_IOPORT
//#define DEBUG_IOPORT

#if !defined(CONFIG_SOFTMMU)
#define PHYS_RAM_MAX_SIZE (256 * 1024 * 1024)
#else
#define PHYS_RAM_MAX_SIZE (2047 * 1024 * 1024)
#endif

#ifdef TARGET_PPC
#define DEFAULT_RAM_SIZE 144
#else
#define DEFAULT_RAM_SIZE 128
#endif
/* in ms */
#define GUI_REFRESH_INTERVAL 30

/* XXX: use a two level table to limit memory usage */
#define MAX_IOPORTS 65536

const char *bios_dir = CONFIG_QEMU_SHAREDIR;
char phys_ram_file[1024];
CPUState *global_env;
CPUState *cpu_single_env;
void *ioport_opaque[MAX_IOPORTS];
IOPortReadFunc *ioport_read_table[3][MAX_IOPORTS];
IOPortWriteFunc *ioport_write_table[3][MAX_IOPORTS];
BlockDriverState *bs_table[MAX_DISKS], *fd_table[MAX_FD];
int vga_ram_size;
int bios_size;
static DisplayState display_state;
int nographic;
const char* keyboard_layout = NULL;
int64_t ticks_per_sec;
int boot_device = 'c';
int ram_size;
static char network_script[1024];
int pit_min_timer_count = 0;
int nb_nics;
NetDriverState nd_table[MAX_NICS];
QEMUTimer *gui_timer;
int vm_running;
int audio_enabled = 0;
int sb16_enabled = 1;
int adlib_enabled = 1;
int gus_enabled = 1;
int pci_enabled = 1;
int prep_enabled = 0;
int rtc_utc = 1;
int cirrus_vga_enabled = 1;
int graphic_width = 800;
int graphic_height = 600;
int graphic_depth = 15;
int full_screen = 0;
TextConsole *vga_console;
CharDriverState *serial_hds[MAX_SERIAL_PORTS];
CharDriverState *parallel_hds[MAX_PARALLEL_PORTS];

/***********************************************************/
/* x86 ISA bus support */

target_phys_addr_t isa_mem_base = 0;

uint32_t default_ioport_readb(void *opaque, uint32_t address)
{
#ifdef DEBUG_UNUSED_IOPORT
    fprintf(stderr, "inb: port=0x%04x\n", address);
#endif
    return 0xff;
}

void default_ioport_writeb(void *opaque, uint32_t address, uint32_t data)
{
#ifdef DEBUG_UNUSED_IOPORT
    fprintf(stderr, "outb: port=0x%04x data=0x%02x\n", address, data);
#endif
}

/* default is to make two byte accesses */
uint32_t default_ioport_readw(void *opaque, uint32_t address)
{
    uint32_t data;
    data = ioport_read_table[0][address](ioport_opaque[address], address);
    address = (address + 1) & (MAX_IOPORTS - 1);
    data |= ioport_read_table[0][address](ioport_opaque[address], address) << 8;
    return data;
}

void default_ioport_writew(void *opaque, uint32_t address, uint32_t data)
{
    ioport_write_table[0][address](ioport_opaque[address], address, data & 0xff);
    address = (address + 1) & (MAX_IOPORTS - 1);
    ioport_write_table[0][address](ioport_opaque[address], address, (data >> 8) & 0xff);
}

uint32_t default_ioport_readl(void *opaque, uint32_t address)
{
#ifdef DEBUG_UNUSED_IOPORT
    fprintf(stderr, "inl: port=0x%04x\n", address);
#endif
    return 0xffffffff;
}

void default_ioport_writel(void *opaque, uint32_t address, uint32_t data)
{
#ifdef DEBUG_UNUSED_IOPORT
    fprintf(stderr, "outl: port=0x%04x data=0x%02x\n", address, data);
#endif
}

void init_ioports(void)
{
    int i;

    for(i = 0; i < MAX_IOPORTS; i++) {
        ioport_read_table[0][i] = default_ioport_readb;
        ioport_write_table[0][i] = default_ioport_writeb;
        ioport_read_table[1][i] = default_ioport_readw;
        ioport_write_table[1][i] = default_ioport_writew;
        ioport_read_table[2][i] = default_ioport_readl;
        ioport_write_table[2][i] = default_ioport_writel;
    }
}

/* size is the word size in byte */
int register_ioport_read(int start, int length, int size, 
                         IOPortReadFunc *func, void *opaque)
{
    int i, bsize;

    if (size == 1) {
        bsize = 0;
    } else if (size == 2) {
        bsize = 1;
    } else if (size == 4) {
        bsize = 2;
    } else {
        hw_error("register_ioport_read: invalid size");
        return -1;
    }
    for(i = start; i < start + length; i += size) {
        ioport_read_table[bsize][i] = func;
        if (ioport_opaque[i] != NULL && ioport_opaque[i] != opaque)
            hw_error("register_ioport_read: invalid opaque");
        ioport_opaque[i] = opaque;
    }
    return 0;
}

/* size is the word size in byte */
int register_ioport_write(int start, int length, int size, 
                          IOPortWriteFunc *func, void *opaque)
{
    int i, bsize;

    if (size == 1) {
        bsize = 0;
    } else if (size == 2) {
        bsize = 1;
    } else if (size == 4) {
        bsize = 2;
    } else {
        hw_error("register_ioport_write: invalid size");
        return -1;
    }
    for(i = start; i < start + length; i += size) {
        ioport_write_table[bsize][i] = func;
        if (ioport_opaque[i] != NULL && ioport_opaque[i] != opaque)
            hw_error("register_ioport_read: invalid opaque");
        ioport_opaque[i] = opaque;
    }
    return 0;
}

void isa_unassign_ioport(int start, int length)
{
    int i;

    for(i = start; i < start + length; i++) {
        ioport_read_table[0][i] = default_ioport_readb;
        ioport_read_table[1][i] = default_ioport_readw;
        ioport_read_table[2][i] = default_ioport_readl;

        ioport_write_table[0][i] = default_ioport_writeb;
        ioport_write_table[1][i] = default_ioport_writew;
        ioport_write_table[2][i] = default_ioport_writel;
    }
}

/***********************************************************/

void pstrcpy(char *buf, int buf_size, const char *str)
{
    int c;
    char *q = buf;

    if (buf_size <= 0)
        return;

    for(;;) {
        c = *str++;
        if (c == 0 || q >= buf + buf_size - 1)
            break;
        *q++ = c;
    }
    *q = '\0';
}

/* strcat and truncate. */
char *pstrcat(char *buf, int buf_size, const char *s)
{
    int len;
    len = strlen(buf);
    if (len < buf_size) 
        pstrcpy(buf + len, buf_size - len, s);
    return buf;
}

int strstart(const char *str, const char *val, const char **ptr)
{
    const char *p, *q;
    p = str;
    q = val;
    while (*q != '\0') {
        if (*p != *q)
            return 0;
        p++;
        q++;
    }
    if (ptr)
        *ptr = p;
    return 1;
}

/* return the size or -1 if error */
int get_image_size(const char *filename)
{
    int fd, size;
    fd = open(filename, O_RDONLY | O_BINARY);
    if (fd < 0)
        return -1;
    size = lseek(fd, 0, SEEK_END);
    close(fd);
    return size;
}

/* return the size or -1 if error */
int load_image(const char *filename, uint8_t *addr)
{
    int fd, size;
    fd = open(filename, O_RDONLY | O_BINARY);
    if (fd < 0)
        return -1;
    size = lseek(fd, 0, SEEK_END);
    lseek(fd, 0, SEEK_SET);
    if (read(fd, addr, size) != size) {
        close(fd);
        return -1;
    }
    close(fd);
    return size;
}

void cpu_outb(CPUState *env, int addr, int val)
{
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "outb: %04x %02x\n", addr, val);
#endif    
    ioport_write_table[0][addr](ioport_opaque[addr], addr, val);
}

void cpu_outw(CPUState *env, int addr, int val)
{
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "outw: %04x %04x\n", addr, val);
#endif    
    ioport_write_table[1][addr](ioport_opaque[addr], addr, val);
}

void cpu_outl(CPUState *env, int addr, int val)
{
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "outl: %04x %08x\n", addr, val);
#endif
    ioport_write_table[2][addr](ioport_opaque[addr], addr, val);
}

int cpu_inb(CPUState *env, int addr)
{
    int val;
    val = ioport_read_table[0][addr](ioport_opaque[addr], addr);
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "inb : %04x %02x\n", addr, val);
#endif
    return val;
}

int cpu_inw(CPUState *env, int addr)
{
    int val;
    val = ioport_read_table[1][addr](ioport_opaque[addr], addr);
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "inw : %04x %04x\n", addr, val);
#endif
    return val;
}

int cpu_inl(CPUState *env, int addr)
{
    int val;
    val = ioport_read_table[2][addr](ioport_opaque[addr], addr);
#ifdef DEBUG_IOPORT
    if (loglevel & CPU_LOG_IOPORT)
        fprintf(logfile, "inl : %04x %08x\n", addr, val);
#endif
    return val;
}

/***********************************************************/
void hw_error(const char *fmt, ...)
{
    va_list ap;

    va_start(ap, fmt);
    fprintf(stderr, "qemu: hardware error: ");
    vfprintf(stderr, fmt, ap);
    fprintf(stderr, "\n");
#ifdef TARGET_I386
    cpu_dump_state(global_env, stderr, fprintf, X86_DUMP_FPU | X86_DUMP_CCOP);
#else
    cpu_dump_state(global_env, stderr, fprintf, 0);
#endif
    va_end(ap);
    abort();
}

/***********************************************************/
/* keyboard/mouse */

static QEMUPutKBDEvent *qemu_put_kbd_event;
static void *qemu_put_kbd_event_opaque;
static QEMUPutMouseEvent *qemu_put_mouse_event;
static void *qemu_put_mouse_event_opaque;

void qemu_add_kbd_event_handler(QEMUPutKBDEvent *func, void *opaque)
{
    qemu_put_kbd_event_opaque = opaque;
    qemu_put_kbd_event = func;
}

void qemu_add_mouse_event_handler(QEMUPutMouseEvent *func, void *opaque)
{
    qemu_put_mouse_event_opaque = opaque;
    qemu_put_mouse_event = func;
}

void kbd_put_keycode(int keycode)
{
    if (qemu_put_kbd_event) {
        qemu_put_kbd_event(qemu_put_kbd_event_opaque, keycode);
    }
}

void kbd_mouse_event(int dx, int dy, int dz, int buttons_state)
{
    if (qemu_put_mouse_event) {
        qemu_put_mouse_event(qemu_put_mouse_event_opaque, 
                             dx, dy, dz, buttons_state);
    }
}

/***********************************************************/
/* timers */

#if defined(__powerpc__)

static inline uint32_t get_tbl(void) 
{
    uint32_t tbl;
    asm volatile("mftb %0" : "=r" (tbl));
    return tbl;
}

static inline uint32_t get_tbu(void) 
{
	uint32_t tbl;
	asm volatile("mftbu %0" : "=r" (tbl));
	return tbl;
}

int64_t cpu_get_real_ticks(void)
{
    uint32_t l, h, h1;
    /* NOTE: we test if wrapping has occurred */
    do {
        h = get_tbu();
        l = get_tbl();
        h1 = get_tbu();
    } while (h != h1);
    return ((int64_t)h << 32) | l;
}

#elif defined(__i386__)

int64_t cpu_get_real_ticks(void)
{
    int64_t val;
    asm volatile ("rdtsc" : "=A" (val));
    return val;
}

#elif defined(__x86_64__)

int64_t cpu_get_real_ticks(void)
{
    uint32_t low,high;
    int64_t val;
    asm volatile("rdtsc" : "=a" (low), "=d" (high));
    val = high;
    val <<= 32;
    val |= low;
    return val;
}

#else
#error unsupported CPU
#endif

static int64_t cpu_ticks_offset;
static int cpu_ticks_enabled;

static inline int64_t cpu_get_ticks(void)
{
    if (!cpu_ticks_enabled) {
        return cpu_ticks_offset;
    } else {
        return cpu_get_real_ticks() + cpu_ticks_offset;
    }
}

/* enable cpu_get_ticks() */
void cpu_enable_ticks(void)
{
    if (!cpu_ticks_enabled) {
        cpu_ticks_offset -= cpu_get_real_ticks();
        cpu_ticks_enabled = 1;
    }
}

/* disable cpu_get_ticks() : the clock is stopped. You must not call
   cpu_get_ticks() after that.  */
void cpu_disable_ticks(void)
{
    if (cpu_ticks_enabled) {
        cpu_ticks_offset = cpu_get_ticks();
        cpu_ticks_enabled = 0;
    }
}

static int64_t get_clock(void)
{
#ifdef _WIN32
    struct _timeb tb;
    _ftime(&tb);
    return ((int64_t)tb.time * 1000 + (int64_t)tb.millitm) * 1000;
#else
    struct timeval tv;
    gettimeofday(&tv, NULL);
    return tv.tv_sec * 1000000LL + tv.tv_usec;
#endif
}

void cpu_calibrate_ticks(void)
{
    int64_t usec, ticks;

    usec = get_clock();
    ticks = cpu_get_real_ticks();
#ifdef _WIN32
    Sleep(50);
#else
    usleep(50 * 1000);
#endif
    usec = get_clock() - usec;
    ticks = cpu_get_real_ticks() - ticks;
    ticks_per_sec = (ticks * 1000000LL + (usec >> 1)) / usec;
}

/* compute with 96 bit intermediate result: (a*b)/c */
uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
{
    union {
        uint64_t ll;
        struct {
#ifdef WORDS_BIGENDIAN
            uint32_t high, low;
#else
            uint32_t low, high;
#endif            
        } l;
    } u, res;
    uint64_t rl, rh;

    u.ll = a;
    rl = (uint64_t)u.l.low * (uint64_t)b;
    rh = (uint64_t)u.l.high * (uint64_t)b;
    rh += (rl >> 32);
    res.l.high = rh / c;
    res.l.low = (((rh % c) << 32) + (rl & 0xffffffff)) / c;
    return res.ll;
}

#define QEMU_TIMER_REALTIME 0
#define QEMU_TIMER_VIRTUAL  1

struct QEMUClock {
    int type;
    /* XXX: add frequency */
};

struct QEMUTimer {
    QEMUClock *clock;
    int64_t expire_time;
    QEMUTimerCB *cb;
    void *opaque;
    struct QEMUTimer *next;
};

QEMUClock *rt_clock;
QEMUClock *vm_clock;

static QEMUTimer *active_timers[2];
#ifdef _WIN32
static MMRESULT timerID;
#else
/* frequency of the times() clock tick */
static int timer_freq;
#endif

QEMUClock *qemu_new_clock(int type)
{
    QEMUClock *clock;
    clock = qemu_mallocz(sizeof(QEMUClock));
    if (!clock)
        return NULL;
    clock->type = type;
    return clock;
}

QEMUTimer *qemu_new_timer(QEMUClock *clock, QEMUTimerCB *cb, void *opaque)
{
    QEMUTimer *ts;

    ts = qemu_mallocz(sizeof(QEMUTimer));
    ts->clock = clock;
    ts->cb = cb;
    ts->opaque = opaque;
    return ts;
}

void qemu_free_timer(QEMUTimer *ts)
{
    qemu_free(ts);
}

/* stop a timer, but do not dealloc it */
void qemu_del_timer(QEMUTimer *ts)
{
    QEMUTimer **pt, *t;

    /* NOTE: this code must be signal safe because
       qemu_timer_expired() can be called from a signal. */
    pt = &active_timers[ts->clock->type];
    for(;;) {
        t = *pt;
        if (!t)
            break;
        if (t == ts) {
            *pt = t->next;
            break;
        }
        pt = &t->next;
    }
}

/* modify the current timer so that it will be fired when current_time
   >= expire_time. The corresponding callback will be called. */
void qemu_mod_timer(QEMUTimer *ts, int64_t expire_time)
{
    QEMUTimer **pt, *t;

    qemu_del_timer(ts);

    /* add the timer in the sorted list */
    /* NOTE: this code must be signal safe because
       qemu_timer_expired() can be called from a signal. */
    pt = &active_timers[ts->clock->type];
    for(;;) {
        t = *pt;
        if (!t)
            break;
        if (t->expire_time > expire_time) 
            break;
        pt = &t->next;
    }
    ts->expire_time = expire_time;
    ts->next = *pt;
    *pt = ts;
}

int qemu_timer_pending(QEMUTimer *ts)
{
    QEMUTimer *t;
    for(t = active_timers[ts->clock->type]; t != NULL; t = t->next) {
        if (t == ts)
            return 1;
    }
    return 0;
}

static inline int qemu_timer_expired(QEMUTimer *timer_head, int64_t current_time)
{
    if (!timer_head)
        return 0;
    return (timer_head->expire_time <= current_time);
}

static void qemu_run_timers(QEMUTimer **ptimer_head, int64_t current_time)
{
    QEMUTimer *ts;
    
    for(;;) {
        ts = *ptimer_head;
        if (!ts || ts->expire_time > current_time)
            break;
        /* remove timer from the list before calling the callback */
        *ptimer_head = ts->next;
        ts->next = NULL;
        
        /* run the callback (the timer list can be modified) */
        ts->cb(ts->opaque);
    }
}

int64_t qemu_get_clock(QEMUClock *clock)
{
    switch(clock->type) {
    case QEMU_TIMER_REALTIME:
#ifdef _WIN32
        return GetTickCount();
#else
        {
            struct tms tp;

            /* Note that using gettimeofday() is not a good solution
               for timers because its value change when the date is
               modified. */
            if (timer_freq == 100) {
                return times(&tp) * 10;
            } else {
                return ((int64_t)times(&tp) * 1000) / timer_freq;
            }
        }
#endif
    default:
    case QEMU_TIMER_VIRTUAL:
        return cpu_get_ticks();
    }
}

/* save a timer */
void qemu_put_timer(QEMUFile *f, QEMUTimer *ts)
{
    uint64_t expire_time;

    if (qemu_timer_pending(ts)) {
        expire_time = ts->expire_time;
    } else {
        expire_time = -1;
    }
    qemu_put_be64(f, expire_time);
}

void qemu_get_timer(QEMUFile *f, QEMUTimer *ts)
{
    uint64_t expire_time;

    expire_time = qemu_get_be64(f);
    if (expire_time != -1) {
        qemu_mod_timer(ts, expire_time);
    } else {
        qemu_del_timer(ts);
    }
}

static void timer_save(QEMUFile *f, void *opaque)
{
    if (cpu_ticks_enabled) {
        hw_error("cannot save state if virtual timers are running");
    }
    qemu_put_be64s(f, &cpu_ticks_offset);
    qemu_put_be64s(f, &ticks_per_sec);
}

static int timer_load(QEMUFile *f, void *opaque, int version_id)
{
    if (version_id != 1)
        return -EINVAL;
    if (cpu_ticks_enabled) {
        return -EINVAL;
    }
    qemu_get_be64s(f, &cpu_ticks_offset);
    qemu_get_be64s(f, &ticks_per_sec);
    return 0;
}

#ifdef _WIN32
void CALLBACK host_alarm_handler(UINT uTimerID, UINT uMsg, 
                                 DWORD_PTR dwUser, DWORD_PTR dw1, DWORD_PTR dw2)
#else
static void host_alarm_handler(int host_signum)
#endif
{
#if 0
#define DISP_FREQ 1000
    {
        static int64_t delta_min = INT64_MAX;
        static int64_t delta_max, delta_cum, last_clock, delta, ti;
        static int count;
        ti = qemu_get_clock(vm_clock);
        if (last_clock != 0) {
            delta = ti - last_clock;
            if (delta < delta_min)
                delta_min = delta;
            if (delta > delta_max)
                delta_max = delta;
            delta_cum += delta;
            if (++count == DISP_FREQ) {
                printf("timer: min=%lld us max=%lld us avg=%lld us avg_freq=%0.3f Hz\n",
                       muldiv64(delta_min, 1000000, ticks_per_sec),
                       muldiv64(delta_max, 1000000, ticks_per_sec),
                       muldiv64(delta_cum, 1000000 / DISP_FREQ, ticks_per_sec),
                       (double)ticks_per_sec / ((double)delta_cum / DISP_FREQ));
                count = 0;
                delta_min = INT64_MAX;
                delta_max = 0;
                delta_cum = 0;
            }
        }
        last_clock = ti;
    }
#endif
    if (qemu_timer_expired(active_timers[QEMU_TIMER_VIRTUAL],
                           qemu_get_clock(vm_clock)) ||
        qemu_timer_expired(active_timers[QEMU_TIMER_REALTIME],
                           qemu_get_clock(rt_clock))) {
        /* stop the cpu because a timer occured */
        cpu_interrupt(global_env, CPU_INTERRUPT_EXIT);
    }
}

#ifndef _WIN32

#if defined(__linux__)

#define RTC_FREQ 1024

static int rtc_fd;

static int start_rtc_timer(void)
{
    rtc_fd = open("/dev/rtc", O_RDONLY);
    if (rtc_fd < 0)
        return -1;
    if (ioctl(rtc_fd, RTC_IRQP_SET, RTC_FREQ) < 0) {
        fprintf(stderr, "Could not configure '/dev/rtc' to have a 1024 Hz timer. This is not a fatal\n"
                "error, but for better emulation accuracy either use a 2.6 host Linux kernel or\n"
                "type 'echo 1024 > /proc/sys/dev/rtc/max-user-freq' as root.\n");
        goto fail;
    }
    if (ioctl(rtc_fd, RTC_PIE_ON, 0) < 0) {
    fail:
        close(rtc_fd);
        return -1;
    }
    pit_min_timer_count = PIT_FREQ / RTC_FREQ;
    return 0;
}

#else

static int start_rtc_timer(void)
{
    return -1;
}

#endif /* !defined(__linux__) */

#endif /* !defined(_WIN32) */

static void init_timers(void)
{
    rt_clock = qemu_new_clock(QEMU_TIMER_REALTIME);
    vm_clock = qemu_new_clock(QEMU_TIMER_VIRTUAL);

#ifdef _WIN32
    {
        int count=0;
        timerID = timeSetEvent(10,    // interval (ms)
                               0,     // resolution
                               host_alarm_handler, // function
                               (DWORD)&count,  // user parameter
                               TIME_PERIODIC | TIME_CALLBACK_FUNCTION);
 	if( !timerID ) {
            perror("failed timer alarm");
            exit(1);
 	}
    }
    pit_min_timer_count = ((uint64_t)10000 * PIT_FREQ) / 1000000;
#else
    {
        struct sigaction act;
        struct itimerval itv;
        
        /* get times() syscall frequency */
        timer_freq = sysconf(_SC_CLK_TCK);
        
        /* timer signal */
        sigfillset(&act.sa_mask);
        act.sa_flags = 0;
#if defined (TARGET_I386) && defined(USE_CODE_COPY)
        act.sa_flags |= SA_ONSTACK;
#endif
        act.sa_handler = host_alarm_handler;
        sigaction(SIGALRM, &act, NULL);

        itv.it_interval.tv_sec = 0;
        itv.it_interval.tv_usec = 1000;
        itv.it_value.tv_sec = 0;
        itv.it_value.tv_usec = 10 * 1000;
        setitimer(ITIMER_REAL, &itv, NULL);
        /* we probe the tick duration of the kernel to inform the user if
           the emulated kernel requested a too high timer frequency */
        getitimer(ITIMER_REAL, &itv);

#if defined(__linux__)
        if (itv.it_interval.tv_usec > 1000) {
            /* try to use /dev/rtc to have a faster timer */
            if (start_rtc_timer() < 0)
                goto use_itimer;
            /* disable itimer */
            itv.it_interval.tv_sec = 0;
            itv.it_interval.tv_usec = 0;
            itv.it_value.tv_sec = 0;
            itv.it_value.tv_usec = 0;
            setitimer(ITIMER_REAL, &itv, NULL);

            /* use the RTC */
            sigaction(SIGIO, &act, NULL);
            fcntl(rtc_fd, F_SETFL, O_ASYNC);
            fcntl(rtc_fd, F_SETOWN, getpid());
        } else 
#endif /* defined(__linux__) */
        {
        use_itimer:
            pit_min_timer_count = ((uint64_t)itv.it_interval.tv_usec * 
                                   PIT_FREQ) / 1000000;
        }
    }
#endif
}

void quit_timers(void)
{
#ifdef _WIN32
    timeKillEvent(timerID);
#endif
}

/***********************************************************/
/* character device */

int qemu_chr_write(CharDriverState *s, const uint8_t *buf, int len)
{
    return s->chr_write(s, buf, len);
}

void qemu_chr_printf(CharDriverState *s, const char *fmt, ...)
{
    char buf[4096];
    va_list ap;
    va_start(ap, fmt);
    vsnprintf(buf, sizeof(buf), fmt, ap);
    qemu_chr_write(s, buf, strlen(buf));
    va_end(ap);
}

void qemu_chr_send_event(CharDriverState *s, int event)
{
    if (s->chr_send_event)
        s->chr_send_event(s, event);
}

void qemu_chr_add_read_handler(CharDriverState *s, 
                               IOCanRWHandler *fd_can_read, 
                               IOReadHandler *fd_read, void *opaque)
{
    s->chr_add_read_handler(s, fd_can_read, fd_read, opaque);
}
             
void qemu_chr_add_event_handler(CharDriverState *s, IOEventHandler *chr_event)
{
    s->chr_event = chr_event;
}

static int null_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    return len;
}

static void null_chr_add_read_handler(CharDriverState *chr, 
                                    IOCanRWHandler *fd_can_read, 
                                    IOReadHandler *fd_read, void *opaque)
{
}

CharDriverState *qemu_chr_open_null(void)
{
    CharDriverState *chr;

    chr = qemu_mallocz(sizeof(CharDriverState));
    if (!chr)
        return NULL;
    chr->chr_write = null_chr_write;
    chr->chr_add_read_handler = null_chr_add_read_handler;
    return chr;
}

#ifndef _WIN32

typedef struct {
    int fd_in, fd_out;
    /* for nographic stdio only */
    IOCanRWHandler *fd_can_read; 
    IOReadHandler *fd_read;
    void *fd_opaque;
} FDCharDriver;

#define STDIO_MAX_CLIENTS 2

static int stdio_nb_clients;
static CharDriverState *stdio_clients[STDIO_MAX_CLIENTS];

static int unix_write(int fd, const uint8_t *buf, int len1)
{
    int ret, len;

    len = len1;
    while (len > 0) {
        ret = write(fd, buf, len);
        if (ret < 0) {
            if (errno != EINTR && errno != EAGAIN)
                return -1;
        } else if (ret == 0) {
            break;
        } else {
            buf += ret;
            len -= ret;
        }
    }
    return len1 - len;
}

static int fd_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
    FDCharDriver *s = chr->opaque;
    return unix_write(s->fd_out, buf, len);
}

static void fd_chr_add_read_handler(CharDriverState *chr, 
                                    IOCanRWHandler *fd_can_read, 
                                    IOReadHandler *fd_read, void *opaque)
{
    FDCharDriver *s = chr->opaque;

    if (nographic && s->fd_in == 0) {
        s->fd_can_read = fd_can_read;
        s->fd_read = fd_read;
        s->fd_opaque = opaque;
    } else {
        qemu_add_fd_read_handler(s->fd_in, fd_can_read, fd_read, opaque);
    }
}

/* open a character device to a unix fd */
CharDriverState *qemu_chr_open_fd(int fd_in, int fd_out)
{
    CharDriverState *chr;
    FDCharDriver *s;

    chr = qemu_mallocz(sizeof(CharDriverState));
    if (!chr)
        return NULL;
    s = qemu_mallocz(sizeof(FDCharDriver));
    if (!s) {
        free(chr);
        return NULL;
    }
    s->fd_in = fd_in;
    s->fd_out = fd_out;
    chr->opaque = s;
    chr->chr_write = fd_chr_write;
    chr->chr_add_read_handler = fd_chr_add_read_handler;
    return chr;
}

/* for STDIO, we handle the case where several clients use it
   (nographic mode) */

#define TERM_ESCAPE 0x01 /* ctrl-a is used for escape */

static int term_got_escape, client_index;

void term_print_help(void)
{
    printf("\n"
           "C-a h    print this help\n"
           "C-a x    exit emulator\n"
           "C-a s    save disk data back to file (if -snapshot)\n"
           "C-a b    send break (magic sysrq)\n"
           "C-a c    switch between console and monitor\n"
           "C-a C-a  send C-a\n"
           );
}

/* called when a char is received */
static void stdio_received_byte(int ch)
{
    if (term_got_escape) {
        term_got_escape = 0;
        switch(ch) {
        case 'h':
            term_print_help();
            break;
        case 'x':
            exit(0);
            break;
        case 's': 
            {
                int i;
                for (i = 0; i < MAX_DISKS; i++) {
                    if (bs_table[i])
                        bdrv_commit(bs_table[i]);
                }
            }
            break;
        case 'b':
            if (client_index < stdio_nb_clients) {
                CharDriverState *chr;
                FDCharDriver *s;

                chr = stdio_clients[client_index];
                s = chr->opaque;
                chr->chr_event(s->fd_opaque, CHR_EVENT_BREAK);
            }
            break;
        case 'c':
            client_index++;
            if (client_index >= stdio_nb_clients)
                client_index = 0;
            if (client_index == 0) {
                /* send a new line in the monitor to get the prompt */
                ch = '\r';
                goto send_char;
            }
            break;
        case TERM_ESCAPE:
            goto send_char;
        }
    } else if (ch == TERM_ESCAPE) {
        term_got_escape = 1;
    } else {
    send_char:
        if (client_index < stdio_nb_clients) {
            uint8_t buf[1];
            CharDriverState *chr;
            FDCharDriver *s;
            
            chr = stdio_clients[client_index];
            s = chr->opaque;
            buf[0] = ch;
            /* XXX: should queue the char if the device is not
               ready */
            if (s->fd_can_read(s->fd_opaque) > 0) 
                s->fd_read(s->fd_opaque, buf, 1);
        }
    }
}

static int stdio_can_read(void *opaque)
{
    /* XXX: not strictly correct */
    return 1;
}

static void stdio_read(void *opaque, const uint8_t *buf, int size)
{
    int i;
    for(i = 0; i < size; i++)
        stdio_received_byte(buf[i]);
}