/*
 * os-win32.c
 *
 * Copyright (c) 2003-2008 Fabrice Bellard
 * Copyright (c) 2010 Red Hat, Inc.
 *
 * QEMU library functions for win32 which are shared between QEMU and
 * the QEMU tools.
 *
 * 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.
 *
 * The implementation of g_poll (functions poll_rest, g_poll) at the end of
 * this file are based on code from GNOME glib-2 and use a different license,
 * see the license comment there.
 */
#include <windows.h>
#include <glib.h>
#include <stdlib.h>
#include "config-host.h"
#include "sysemu/sysemu.h"
#include "qemu/main-loop.h"
#include "trace.h"
#include "qemu/sockets.h"

/* this must come after including "trace.h" */
#include <shlobj.h>

void *qemu_oom_check(void *ptr)
{
    if (ptr == NULL) {
        fprintf(stderr, "Failed to allocate memory: %lu\n", GetLastError());
        abort();
    }
    return ptr;
}

void *qemu_memalign(size_t alignment, size_t size)
{
    void *ptr;

    if (!size) {
        abort();
    }
    ptr = qemu_oom_check(VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE));
    trace_qemu_memalign(alignment, size, ptr);
    return ptr;
}

void *qemu_anon_ram_alloc(size_t size)
{
    void *ptr;

    /* FIXME: this is not exactly optimal solution since VirtualAlloc
       has 64Kb granularity, but at least it guarantees us that the
       memory is page aligned. */
    ptr = VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE);
    trace_qemu_anon_ram_alloc(size, ptr);
    return ptr;
}

void qemu_vfree(void *ptr)
{
    trace_qemu_vfree(ptr);
    if (ptr) {
        VirtualFree(ptr, 0, MEM_RELEASE);
    }
}

void qemu_anon_ram_free(void *ptr, size_t size)
{
    trace_qemu_anon_ram_free(ptr, size);
    if (ptr) {
        VirtualFree(ptr, 0, MEM_RELEASE);
    }
}

/* FIXME: add proper locking */
struct tm *gmtime_r(const time_t *timep, struct tm *result)
{
    struct tm *p = gmtime(timep);
    memset(result, 0, sizeof(*result));
    if (p) {
        *result = *p;
        p = result;
    }
    return p;
}

/* FIXME: add proper locking */
struct tm *localtime_r(const time_t *timep, struct tm *result)
{
    struct tm *p = localtime(timep);
    memset(result, 0, sizeof(*result));
    if (p) {
        *result = *p;
        p = result;
    }
    return p;
}

void qemu_set_block(int fd)
{
    unsigned long opt = 0;
    WSAEventSelect(fd, NULL, 0);
    ioctlsocket(fd, FIONBIO, &opt);
}

void qemu_set_nonblock(int fd)
{
    unsigned long opt = 1;
    ioctlsocket(fd, FIONBIO, &opt);
    qemu_fd_register(fd);
}

int socket_set_fast_reuse(int fd)
{
    /* Enabling the reuse of an endpoint that was used by a socket still in
     * TIME_WAIT state is usually performed by setting SO_REUSEADDR. On Windows
     * fast reuse is the default and SO_REUSEADDR does strange things. So we
     * don't have to do anything here. More info can be found at:
     * http://msdn.microsoft.com/en-us/library/windows/desktop/ms740621.aspx */
    return 0;
}

int inet_aton(const char *cp, struct in_addr *ia)
{
    uint32_t addr = inet_addr(cp);
    if (addr == 0xffffffff) {
        return 0;
    }
    ia->s_addr = addr;
    return 1;
}

void qemu_set_cloexec(int fd)
{
}

/* Offset between 1/1/1601 and 1/1/1970 in 100 nanosec units */
#define _W32_FT_OFFSET (116444736000000000ULL)

int qemu_gettimeofday(qemu_timeval *tp)
{
  union {
    unsigned long long ns100; /*time since 1 Jan 1601 in 100ns units */
    FILETIME ft;
  }  _now;

  if(tp) {
      GetSystemTimeAsFileTime (&_now.ft);
      tp->tv_usec=(long)((_now.ns100 / 10ULL) % 1000000ULL );
      tp->tv_sec= (long)((_now.ns100 - _W32_FT_OFFSET) / 10000000ULL);
  }
  /* Always return 0 as per Open Group Base Specifications Issue 6.
     Do not set errno on error.  */
  return 0;
}

int qemu_get_thread_id(void)
{
    return GetCurrentThreadId();
}

char *
qemu_get_local_state_pathname(const char *relative_pathname)
{
    HRESULT result;
    char base_path[MAX_PATH+1] = "";

    result = SHGetFolderPath(NULL, CSIDL_COMMON_APPDATA, NULL,
                             /* SHGFP_TYPE_CURRENT */ 0, base_path);
    if (result != S_OK) {
        /* misconfigured environment */
        g_critical("CSIDL_COMMON_APPDATA unavailable: %ld", (long)result);
        abort();
    }
    return g_strdup_printf("%s" G_DIR_SEPARATOR_S "%s", base_path,
                           relative_pathname);
}

void qemu_set_tty_echo(int fd, bool echo)
{
    HANDLE handle = (HANDLE)_get_osfhandle(fd);
    DWORD dwMode = 0;

    if (handle == INVALID_HANDLE_VALUE) {
        return;
    }

    GetConsoleMode(handle, &dwMode);

    if (echo) {
        SetConsoleMode(handle, dwMode | ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT);
    } else {
        SetConsoleMode(handle,
                       dwMode & ~(ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT));
    }
}

static char exec_dir[PATH_MAX];

void qemu_init_exec_dir(const char *argv0)
{

    char *p;
    char buf[MAX_PATH];
    DWORD len;

    len = GetModuleFileName(NULL, buf, sizeof(buf) - 1);
    if (len == 0) {
        return;
    }

    buf[len] = 0;
    p = buf + len - 1;
    while (p != buf && *p != '\\') {
        p--;
    }
    *p = 0;
    if (access(buf, R_OK) == 0) {
        pstrcpy(exec_dir, sizeof(exec_dir), buf);
    }
}

char *qemu_get_exec_dir(void)
{
    return g_strdup(exec_dir);
}

/*
 * The original implementation of g_poll from glib has a problem on Windows
 * when using timeouts < 10 ms.
 *
 * Whenever g_poll is called with timeout < 10 ms, it does a quick poll instead
 * of wait. This causes significant performance degradation of QEMU.
 *
 * The following code is a copy of the original code from glib/gpoll.c
 * (glib commit 20f4d1820b8d4d0fc4447188e33efffd6d4a88d8 from 2014-02-19).
 * Some debug code was removed and the code was reformatted.
 * All other code modifications are marked with 'QEMU'.
 */

/*
 * gpoll.c: poll(2) abstraction
 * Copyright 1998 Owen Taylor
 * Copyright 2008 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

static int poll_rest(gboolean poll_msgs, HANDLE *handles, gint nhandles,
                     GPollFD *fds, guint nfds, gint timeout)
{
    DWORD ready;
    GPollFD *f;
    int recursed_result;

    if (poll_msgs) {
        /* Wait for either messages or handles
         * -> Use MsgWaitForMultipleObjectsEx
         */
        ready = MsgWaitForMultipleObjectsEx(nhandles, handles, timeout,
                                            QS_ALLINPUT, MWMO_ALERTABLE);

        if (ready == WAIT_FAILED) {
            gchar *emsg = g_win32_error_message(GetLastError());
            g_warning("MsgWaitForMultipleObjectsEx failed: %s", emsg);
            g_free(emsg);
        }
    } else if (nhandles == 0) {
        /* No handles to wait for, just the timeout */
        if (timeout == INFINITE) {
            ready = WAIT_FAILED;
        } else {
            SleepEx(timeout, TRUE);
            ready = WAIT_TIMEOUT;
        }
    } else {
        /* Wait for just handles
         * -> Use WaitForMultipleObjectsEx
         */
        ready =
            WaitForMultipleObjectsEx(nhandles, handles, FALSE, timeout, TRUE);
        if (ready == WAIT_FAILED) {
            gchar *emsg = g_win32_error_message(GetLastError());
            g_warning("WaitForMultipleObjectsEx failed: %s", emsg);
            g_free(emsg);
        }
    }

    if (ready == WAIT_FAILED) {
        return -1;
    } else if (ready == WAIT_TIMEOUT || ready == WAIT_IO_COMPLETION) {
        return 0;
    } else if (poll_msgs && ready == WAIT_OBJECT_0 + nhandles) {
        for (f = fds; f < &fds[nfds]; ++f) {
            if (f->fd == G_WIN32_MSG_HANDLE && f->events & G_IO_IN) {
                f->revents |= G_IO_IN;
            }
        }

        /* If we have a timeout, or no handles to poll, be satisfied
         * with just noticing we have messages waiting.
         */
        if (timeout != 0 || nhandles == 0) {
            return 1;
        }

        /* If no timeout and handles to poll, recurse to poll them,
         * too.
         */
        recursed_result = poll_rest(FALSE, handles, nhandles, fds, nfds, 0);
        return (recursed_result == -1) ? -1 : 1 + recursed_result;
    } else if (/* QEMU: removed the following unneeded statement which causes
                * a compiler warning: ready >= WAIT_OBJECT_0 && */
               ready < WAIT_OBJECT_0 + nhandles) {
        for (f = fds; f < &fds[nfds]; ++f) {
            if ((HANDLE) f->fd == handles[ready - WAIT_OBJECT_0]) {
                f->revents = f->events;
            }
        }

        /* If no timeout and polling several handles, recurse to poll
         * the rest of them.
         */
        if (timeout == 0 && nhandles > 1) {
            /* Remove the handle that fired */
            int i;
            if (ready < nhandles - 1) {
                for (i = ready - WAIT_OBJECT_0 + 1; i < nhandles; i++) {
                    handles[i-1] = handles[i];
                }
            }
            nhandles--;
            recursed_result = poll_rest(FALSE, handles, nhandles, fds, nfds, 0);
            return (recursed_result == -1) ? -1 : 1 + recursed_result;
        }
        return 1;
    }

    return 0;
}

gint g_poll(GPollFD *fds, guint nfds, gint timeout)
{
    HANDLE handles[MAXIMUM_WAIT_OBJECTS];
    gboolean poll_msgs = FALSE;
    GPollFD *f;
    gint nhandles = 0;
    int retval;

    for (f = fds; f < &fds[nfds]; ++f) {
        if (f->fd == G_WIN32_MSG_HANDLE && (f->events & G_IO_IN)) {
            poll_msgs = TRUE;
        } else if (f->fd > 0) {
            /* Don't add the same handle several times into the array, as
             * docs say that is not allowed, even if it actually does seem
             * to work.
             */
            gint i;

            for (i = 0; i < nhandles; i++) {
                if (handles[i] == (HANDLE) f->fd) {
                    break;
                }
            }

            if (i == nhandles) {
                if (nhandles == MAXIMUM_WAIT_OBJECTS) {
                    g_warning("Too many handles to wait for!\n");
                    break;
                } else {
                    handles[nhandles++] = (HANDLE) f->fd;
                }
            }
        }
    }

    for (f = fds; f < &fds[nfds]; ++f) {
        f->revents = 0;
    }

    if (timeout == -1) {
        timeout = INFINITE;
    }

    /* Polling for several things? */
    if (nhandles > 1 || (nhandles > 0 && poll_msgs)) {
        /* First check if one or several of them are immediately
         * available
         */
        retval = poll_rest(poll_msgs, handles, nhandles, fds, nfds, 0);

        /* If not, and we have a significant timeout, poll again with
         * timeout then. Note that this will return indication for only
         * one event, or only for messages. We ignore timeouts less than
         * ten milliseconds as they are mostly pointless on Windows, the
         * MsgWaitForMultipleObjectsEx() call will timeout right away
         * anyway.
         *
         * Modification for QEMU: replaced timeout >= 10 by timeout > 0.
         */
        if (retval == 0 && (timeout == INFINITE || timeout > 0)) {
            retval = poll_rest(poll_msgs, handles, nhandles,
                               fds, nfds, timeout);
        }
    } else {
        /* Just polling for one thing, so no need to check first if
         * available immediately
         */
        retval = poll_rest(poll_msgs, handles, nhandles, fds, nfds, timeout);
    }

    if (retval == -1) {
        for (f = fds; f < &fds[nfds]; ++f) {
            f->revents = 0;
        }
    }

    return retval;
}