/*
 * QEMU Guest Agent win32-specific command implementations
 *
 * Copyright IBM Corp. 2012
 *
 * Authors:
 *  Michael Roth      <mdroth@linux.vnet.ibm.com>
 *  Gal Hammer        <ghammer@redhat.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 */

#include <glib.h>
#include <wtypes.h>
#include <powrprof.h>
#include <stdio.h>
#include <string.h>
#include "qga/guest-agent-core.h"
#include "qga/vss-win32.h"
#include "qga-qmp-commands.h"
#include "qapi/qmp/qerror.h"
#include "qemu/queue.h"

#ifndef SHTDN_REASON_FLAG_PLANNED
#define SHTDN_REASON_FLAG_PLANNED 0x80000000
#endif

/* multiple of 100 nanoseconds elapsed between windows baseline
 *    (1/1/1601) and Unix Epoch (1/1/1970), accounting for leap years */
#define W32_FT_OFFSET (10000000ULL * 60 * 60 * 24 * \
                       (365 * (1970 - 1601) +       \
                        (1970 - 1601) / 4 - 3))

#define INVALID_SET_FILE_POINTER ((DWORD)-1)

typedef struct GuestFileHandle {
    int64_t id;
    HANDLE fh;
    QTAILQ_ENTRY(GuestFileHandle) next;
} GuestFileHandle;

static struct {
    QTAILQ_HEAD(, GuestFileHandle) filehandles;
} guest_file_state;


typedef struct OpenFlags {
    const char *forms;
    DWORD desired_access;
    DWORD creation_disposition;
} OpenFlags;
static OpenFlags guest_file_open_modes[] = {
    {"r",   GENERIC_READ,               OPEN_EXISTING},
    {"rb",  GENERIC_READ,               OPEN_EXISTING},
    {"w",   GENERIC_WRITE,              CREATE_ALWAYS},
    {"wb",  GENERIC_WRITE,              CREATE_ALWAYS},
    {"a",   GENERIC_WRITE,              OPEN_ALWAYS  },
    {"r+",  GENERIC_WRITE|GENERIC_READ, OPEN_EXISTING},
    {"rb+", GENERIC_WRITE|GENERIC_READ, OPEN_EXISTING},
    {"r+b", GENERIC_WRITE|GENERIC_READ, OPEN_EXISTING},
    {"w+",  GENERIC_WRITE|GENERIC_READ, CREATE_ALWAYS},
    {"wb+", GENERIC_WRITE|GENERIC_READ, CREATE_ALWAYS},
    {"w+b", GENERIC_WRITE|GENERIC_READ, CREATE_ALWAYS},
    {"a+",  GENERIC_WRITE|GENERIC_READ, OPEN_ALWAYS  },
    {"ab+", GENERIC_WRITE|GENERIC_READ, OPEN_ALWAYS  },
    {"a+b", GENERIC_WRITE|GENERIC_READ, OPEN_ALWAYS  }
};

static OpenFlags *find_open_flag(const char *mode_str)
{
    int mode;
    Error **errp = NULL;

    for (mode = 0; mode < ARRAY_SIZE(guest_file_open_modes); ++mode) {
        OpenFlags *flags = guest_file_open_modes + mode;

        if (strcmp(flags->forms, mode_str) == 0) {
            return flags;
        }
    }

    error_setg(errp, "invalid file open mode '%s'", mode_str);
    return NULL;
}

static int64_t guest_file_handle_add(HANDLE fh, Error **errp)
{
    GuestFileHandle *gfh;
    int64_t handle;

    handle = ga_get_fd_handle(ga_state, errp);
    if (handle < 0) {
        return -1;
    }
    gfh = g_malloc0(sizeof(GuestFileHandle));
    gfh->id = handle;
    gfh->fh = fh;
    QTAILQ_INSERT_TAIL(&guest_file_state.filehandles, gfh, next);

    return handle;
}

static GuestFileHandle *guest_file_handle_find(int64_t id, Error **errp)
{
    GuestFileHandle *gfh;
    QTAILQ_FOREACH(gfh, &guest_file_state.filehandles, next) {
        if (gfh->id == id) {
            return gfh;
        }
    }
    error_setg(errp, "handle '%" PRId64 "' has not been found", id);
    return NULL;
}

int64_t qmp_guest_file_open(const char *path, bool has_mode,
                            const char *mode, Error **errp)
{
    int64_t fd;
    HANDLE fh;
    HANDLE templ_file = NULL;
    DWORD share_mode = FILE_SHARE_READ;
    DWORD flags_and_attr = FILE_ATTRIBUTE_NORMAL;
    LPSECURITY_ATTRIBUTES sa_attr = NULL;
    OpenFlags *guest_flags;

    if (!has_mode) {
        mode = "r";
    }
    slog("guest-file-open called, filepath: %s, mode: %s", path, mode);
    guest_flags = find_open_flag(mode);
    if (guest_flags == NULL) {
        error_setg(errp, "invalid file open mode");
        return -1;
    }

    fh = CreateFile(path, guest_flags->desired_access, share_mode, sa_attr,
                    guest_flags->creation_disposition, flags_and_attr,
                    templ_file);
    if (fh == INVALID_HANDLE_VALUE) {
        error_setg_win32(errp, GetLastError(), "failed to open file '%s'",
                         path);
        return -1;
    }

    fd = guest_file_handle_add(fh, errp);
    if (fd < 0) {
        CloseHandle(&fh);
        error_setg(errp, "failed to add handle to qmp handle table");
        return -1;
    }

    slog("guest-file-open, handle: % " PRId64, fd);
    return fd;
}

void qmp_guest_file_close(int64_t handle, Error **errp)
{
    bool ret;
    GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
    slog("guest-file-close called, handle: %" PRId64, handle);
    if (gfh == NULL) {
        return;
    }
    ret = CloseHandle(gfh->fh);
    if (!ret) {
        error_setg_win32(errp, GetLastError(), "failed close handle");
        return;
    }

    QTAILQ_REMOVE(&guest_file_state.filehandles, gfh, next);
    g_free(gfh);
}

static void acquire_privilege(const char *name, Error **errp)
{
    HANDLE token = NULL;
    TOKEN_PRIVILEGES priv;
    Error *local_err = NULL;

    if (OpenProcessToken(GetCurrentProcess(),
        TOKEN_ADJUST_PRIVILEGES|TOKEN_QUERY, &token))
    {
        if (!LookupPrivilegeValue(NULL, name, &priv.Privileges[0].Luid)) {
            error_set(&local_err, QERR_QGA_COMMAND_FAILED,
                      "no luid for requested privilege");
            goto out;
        }

        priv.PrivilegeCount = 1;
        priv.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;

        if (!AdjustTokenPrivileges(token, FALSE, &priv, 0, NULL, 0)) {
            error_set(&local_err, QERR_QGA_COMMAND_FAILED,
                      "unable to acquire requested privilege");
            goto out;
        }

    } else {
        error_set(&local_err, QERR_QGA_COMMAND_FAILED,
                  "failed to open privilege token");
    }

out:
    if (token) {
        CloseHandle(token);
    }
    if (local_err) {
        error_propagate(errp, local_err);
    }
}

static void execute_async(DWORD WINAPI (*func)(LPVOID), LPVOID opaque,
                          Error **errp)
{
    Error *local_err = NULL;

    HANDLE thread = CreateThread(NULL, 0, func, opaque, 0, NULL);
    if (!thread) {
        error_set(&local_err, QERR_QGA_COMMAND_FAILED,
                  "failed to dispatch asynchronous command");
        error_propagate(errp, local_err);
    }
}

void qmp_guest_shutdown(bool has_mode, const char *mode, Error **errp)
{
    Error *local_err = NULL;
    UINT shutdown_flag = EWX_FORCE;

    slog("guest-shutdown called, mode: %s", mode);

    if (!has_mode || strcmp(mode, "powerdown") == 0) {
        shutdown_flag |= EWX_POWEROFF;
    } else if (strcmp(mode, "halt") == 0) {
        shutdown_flag |= EWX_SHUTDOWN;
    } else if (strcmp(mode, "reboot") == 0) {
        shutdown_flag |= EWX_REBOOT;
    } else {
        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "mode",
                  "halt|powerdown|reboot");
        return;
    }

    /* Request a shutdown privilege, but try to shut down the system
       anyway. */
    acquire_privilege(SE_SHUTDOWN_NAME, &local_err);
    if (local_err) {
        error_propagate(errp, local_err);
        return;
    }

    if (!ExitWindowsEx(shutdown_flag, SHTDN_REASON_FLAG_PLANNED)) {
        slog("guest-shutdown failed: %lu", GetLastError());
        error_set(errp, QERR_UNDEFINED_ERROR);
    }
}

GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
                                   int64_t count, Error **errp)
{
    GuestFileRead *read_data = NULL;
    guchar *buf;
    HANDLE fh;
    bool is_ok;
    DWORD read_count;
    GuestFileHandle *gfh = guest_file_handle_find(handle, errp);

    if (!gfh) {
        return NULL;
    }
    if (!has_count) {
        count = QGA_READ_COUNT_DEFAULT;
    } else if (count < 0) {
        error_setg(errp, "value '%" PRId64
                   "' is invalid for argument count", count);
        return NULL;
    }

    fh = gfh->fh;
    buf = g_malloc0(count+1);
    is_ok = ReadFile(fh, buf, count, &read_count, NULL);
    if (!is_ok) {
        error_setg_win32(errp, GetLastError(), "failed to read file");
        slog("guest-file-read failed, handle %" PRId64, handle);
    } else {
        buf[read_count] = 0;
        read_data = g_malloc0(sizeof(GuestFileRead));
        read_data->count = (size_t)read_count;
        read_data->eof = read_count == 0;

        if (read_count != 0) {
            read_data->buf_b64 = g_base64_encode(buf, read_count);
        }
    }
    g_free(buf);

    return read_data;
}

GuestFileWrite *qmp_guest_file_write(int64_t handle, const char *buf_b64,
                                     bool has_count, int64_t count,
                                     Error **errp)
{
    GuestFileWrite *write_data = NULL;
    guchar *buf;
    gsize buf_len;
    bool is_ok;
    DWORD write_count;
    GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
    HANDLE fh;

    if (!gfh) {
        return NULL;
    }
    fh = gfh->fh;
    buf = g_base64_decode(buf_b64, &buf_len);

    if (!has_count) {
        count = buf_len;
    } else if (count < 0 || count > buf_len) {
        error_setg(errp, "value '%" PRId64
                   "' is invalid for argument count", count);
        goto done;
    }

    is_ok = WriteFile(fh, buf, count, &write_count, NULL);
    if (!is_ok) {
        error_setg_win32(errp, GetLastError(), "failed to write to file");
        slog("guest-file-write-failed, handle: %" PRId64, handle);
    } else {
        write_data = g_malloc0(sizeof(GuestFileWrite));
        write_data->count = (size_t) write_count;
    }

done:
    g_free(buf);
    return write_data;
}

GuestFileSeek *qmp_guest_file_seek(int64_t handle, int64_t offset,
                                   int64_t whence, Error **errp)
{
    GuestFileHandle *gfh;
    GuestFileSeek *seek_data;
    HANDLE fh;
    LARGE_INTEGER new_pos, off_pos;
    off_pos.QuadPart = offset;
    BOOL res;
    gfh = guest_file_handle_find(handle, errp);
    if (!gfh) {
        return NULL;
    }

    fh = gfh->fh;
    res = SetFilePointerEx(fh, off_pos, &new_pos, whence);
    if (!res) {
        error_setg_win32(errp, GetLastError(), "failed to seek file");
        return NULL;
    }
    seek_data = g_new0(GuestFileSeek, 1);
    seek_data->position = new_pos.QuadPart;
    return seek_data;
}

void qmp_guest_file_flush(int64_t handle, Error **errp)
{
    HANDLE fh;
    GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
    if (!gfh) {
        return;
    }

    fh = gfh->fh;
    if (!FlushFileBuffers(fh)) {
        error_setg_win32(errp, GetLastError(), "failed to flush file");
    }
}

static void guest_file_init(void)
{
    QTAILQ_INIT(&guest_file_state.filehandles);
}

GuestFilesystemInfoList *qmp_guest_get_fsinfo(Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);
    return NULL;
}

/*
 * Return status of freeze/thaw
 */
GuestFsfreezeStatus qmp_guest_fsfreeze_status(Error **errp)
{
    if (!vss_initialized()) {
        error_set(errp, QERR_UNSUPPORTED);
        return 0;
    }

    if (ga_is_frozen(ga_state)) {
        return GUEST_FSFREEZE_STATUS_FROZEN;
    }

    return GUEST_FSFREEZE_STATUS_THAWED;
}

/*
 * Freeze local file systems using Volume Shadow-copy Service.
 * The frozen state is limited for up to 10 seconds by VSS.
 */
int64_t qmp_guest_fsfreeze_freeze(Error **errp)
{
    int i;
    Error *local_err = NULL;

    if (!vss_initialized()) {
        error_set(errp, QERR_UNSUPPORTED);
        return 0;
    }

    slog("guest-fsfreeze called");

    /* cannot risk guest agent blocking itself on a write in this state */
    ga_set_frozen(ga_state);

    qga_vss_fsfreeze(&i, &local_err, true);
    if (local_err) {
        error_propagate(errp, local_err);
        goto error;
    }

    return i;

error:
    local_err = NULL;
    qmp_guest_fsfreeze_thaw(&local_err);
    if (local_err) {
        g_debug("cleanup thaw: %s", error_get_pretty(local_err));
        error_free(local_err);
    }
    return 0;
}

int64_t qmp_guest_fsfreeze_freeze_list(bool has_mountpoints,
                                       strList *mountpoints,
                                       Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);

    return 0;
}

/*
 * Thaw local file systems using Volume Shadow-copy Service.
 */
int64_t qmp_guest_fsfreeze_thaw(Error **errp)
{
    int i;

    if (!vss_initialized()) {
        error_set(errp, QERR_UNSUPPORTED);
        return 0;
    }

    qga_vss_fsfreeze(&i, errp, false);

    ga_unset_frozen(ga_state);
    return i;
}

static void guest_fsfreeze_cleanup(void)
{
    Error *err = NULL;

    if (!vss_initialized()) {
        return;
    }

    if (ga_is_frozen(ga_state) == GUEST_FSFREEZE_STATUS_FROZEN) {
        qmp_guest_fsfreeze_thaw(&err);
        if (err) {
            slog("failed to clean up frozen filesystems: %s",
                 error_get_pretty(err));
            error_free(err);
        }
    }

    vss_deinit(true);
}

/*
 * Walk list of mounted file systems in the guest, and discard unused
 * areas.
 */
void qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);
}

typedef enum {
    GUEST_SUSPEND_MODE_DISK,
    GUEST_SUSPEND_MODE_RAM
} GuestSuspendMode;

static void check_suspend_mode(GuestSuspendMode mode, Error **errp)
{
    SYSTEM_POWER_CAPABILITIES sys_pwr_caps;
    Error *local_err = NULL;

    ZeroMemory(&sys_pwr_caps, sizeof(sys_pwr_caps));
    if (!GetPwrCapabilities(&sys_pwr_caps)) {
        error_set(&local_err, QERR_QGA_COMMAND_FAILED,
                  "failed to determine guest suspend capabilities");
        goto out;
    }

    switch (mode) {
    case GUEST_SUSPEND_MODE_DISK:
        if (!sys_pwr_caps.SystemS4) {
            error_set(&local_err, QERR_QGA_COMMAND_FAILED,
                      "suspend-to-disk not supported by OS");
        }
        break;
    case GUEST_SUSPEND_MODE_RAM:
        if (!sys_pwr_caps.SystemS3) {
            error_set(&local_err, QERR_QGA_COMMAND_FAILED,
                      "suspend-to-ram not supported by OS");
        }
        break;
    default:
        error_set(&local_err, QERR_INVALID_PARAMETER_VALUE, "mode",
                  "GuestSuspendMode");
    }

out:
    if (local_err) {
        error_propagate(errp, local_err);
    }
}

static DWORD WINAPI do_suspend(LPVOID opaque)
{
    GuestSuspendMode *mode = opaque;
    DWORD ret = 0;

    if (!SetSuspendState(*mode == GUEST_SUSPEND_MODE_DISK, TRUE, TRUE)) {
        slog("failed to suspend guest, %lu", GetLastError());
        ret = -1;
    }
    g_free(mode);
    return ret;
}

void qmp_guest_suspend_disk(Error **errp)
{
    Error *local_err = NULL;
    GuestSuspendMode *mode = g_malloc(sizeof(GuestSuspendMode));

    *mode = GUEST_SUSPEND_MODE_DISK;
    check_suspend_mode(*mode, &local_err);
    acquire_privilege(SE_SHUTDOWN_NAME, &local_err);
    execute_async(do_suspend, mode, &local_err);

    if (local_err) {
        error_propagate(errp, local_err);
        g_free(mode);
    }
}

void qmp_guest_suspend_ram(Error **errp)
{
    Error *local_err = NULL;
    GuestSuspendMode *mode = g_malloc(sizeof(GuestSuspendMode));

    *mode = GUEST_SUSPEND_MODE_RAM;
    check_suspend_mode(*mode, &local_err);
    acquire_privilege(SE_SHUTDOWN_NAME, &local_err);
    execute_async(do_suspend, mode, &local_err);

    if (local_err) {
        error_propagate(errp, local_err);
        g_free(mode);
    }
}

void qmp_guest_suspend_hybrid(Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);
}

GuestNetworkInterfaceList *qmp_guest_network_get_interfaces(Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);
    return NULL;
}

int64_t qmp_guest_get_time(Error **errp)
{
    SYSTEMTIME ts = {0};
    int64_t time_ns;
    FILETIME tf;

    GetSystemTime(&ts);
    if (ts.wYear < 1601 || ts.wYear > 30827) {
        error_setg(errp, "Failed to get time");
        return -1;
    }

    if (!SystemTimeToFileTime(&ts, &tf)) {
        error_setg(errp, "Failed to convert system time: %d", (int)GetLastError());
        return -1;
    }

    time_ns = ((((int64_t)tf.dwHighDateTime << 32) | tf.dwLowDateTime)
                - W32_FT_OFFSET) * 100;

    return time_ns;
}

void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp)
{
    Error *local_err = NULL;
    SYSTEMTIME ts;
    FILETIME tf;
    LONGLONG time;

    if (!has_time) {
        /* Unfortunately, Windows libraries don't provide an easy way to access
         * RTC yet:
         *
         * https://msdn.microsoft.com/en-us/library/aa908981.aspx
         */
        error_setg(errp, "Time argument is required on this platform");
        return;
    }

    /* Validate time passed by user. */
    if (time_ns < 0 || time_ns / 100 > INT64_MAX - W32_FT_OFFSET) {
        error_setg(errp, "Time %" PRId64 "is invalid", time_ns);
        return;
    }

    time = time_ns / 100 + W32_FT_OFFSET;

    tf.dwLowDateTime = (DWORD) time;
    tf.dwHighDateTime = (DWORD) (time >> 32);

    if (!FileTimeToSystemTime(&tf, &ts)) {
        error_setg(errp, "Failed to convert system time %d",
                   (int)GetLastError());
        return;
    }

    acquire_privilege(SE_SYSTEMTIME_NAME, &local_err);
    if (local_err) {
        error_propagate(errp, local_err);
        return;
    }

    if (!SetSystemTime(&ts)) {
        error_setg(errp, "Failed to set time to guest: %d", (int)GetLastError());
        return;
    }
}

GuestLogicalProcessorList *qmp_guest_get_vcpus(Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);
    return NULL;
}

int64_t qmp_guest_set_vcpus(GuestLogicalProcessorList *vcpus, Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);
    return -1;
}

void qmp_guest_set_user_password(const char *username,
                                 const char *password,
                                 bool crypted,
                                 Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);
}

GuestMemoryBlockList *qmp_guest_get_memory_blocks(Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);
    return NULL;
}

GuestMemoryBlockResponseList *
qmp_guest_set_memory_blocks(GuestMemoryBlockList *mem_blks, Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);
    return NULL;
}

GuestMemoryBlockInfo *qmp_guest_get_memory_block_info(Error **errp)
{
    error_set(errp, QERR_UNSUPPORTED);
    return NULL;
}

/* add unsupported commands to the blacklist */
GList *ga_command_blacklist_init(GList *blacklist)
{
    const char *list_unsupported[] = {
        "guest-suspend-hybrid", "guest-network-get-interfaces",
        "guest-get-vcpus", "guest-set-vcpus",
        "guest-set-user-password",
        "guest-get-memory-blocks", "guest-set-memory-blocks",
        "guest-get-memory-block-size",
        "guest-fsfreeze-freeze-list", "guest-get-fsinfo",
        "guest-fstrim", NULL};
    char **p = (char **)list_unsupported;

    while (*p) {
        blacklist = g_list_append(blacklist, *p++);
    }

    if (!vss_init(true)) {
        const char *list[] = {
            "guest-get-fsinfo", "guest-fsfreeze-status",
            "guest-fsfreeze-freeze", "guest-fsfreeze-thaw", NULL};
        p = (char **)list;

        while (*p) {
            blacklist = g_list_append(blacklist, *p++);
        }
    }

    return blacklist;
}

/* register init/cleanup routines for stateful command groups */
void ga_command_state_init(GAState *s, GACommandState *cs)
{
    if (!vss_initialized()) {
        ga_command_state_add(cs, NULL, guest_fsfreeze_cleanup);
    }
    ga_command_state_add(cs, guest_file_init, NULL);
}