/* Attempt to impersonate a client and open a file for the filedisk. */
static NTSTATUS STDCALL WvFilediskOpen_(
IN WV_SP_FILEDISK_T filedisk,
IN PANSI_STRING file_path
) {
WV_S_FILEDISK_OPENER_ opener;
/* Allocate and convert the file path from ANSI to Unicode. */
opener.status = RtlAnsiStringToUnicodeString(
opener.file_path,
file_path,
TRUE
);
if (!NT_SUCCESS(opener.status)) {
DBG("Couldn't allocate Unicode file path!\n");
goto err_ansi_to_unicode;
}
/* Build the impersonation context. */
opener.status = WvFilediskCreateClientSecurity(&filedisk->impersonation);
if (!NT_SUCCESS(opener.status)) {
DBG("Couldn't build impersonation context!\n");
goto err_impersonation;
}
/* Build the rest of the work item. */
opener.item->Func = WvFilediskOpenInThread_;
opener.filedisk = filedisk;
KeInitializeEvent(opener.completion, SynchronizationEvent, FALSE);
/* Attempt to open the file from within the filedisk's thread. */
if (!(WvlThreadAddItem(filedisk->Thread, opener.item))) {
DBG("Filedisk thread not active!\n");
goto err_add_item;
}
KeWaitForSingleObject(
opener.completion,
Executive,
KernelMode,
FALSE,
NULL
);
/* Fall through to free resources and return status. */
err_add_item:
err_impersonation:
RtlFreeUnicodeString(opener.file_path);
err_ansi_to_unicode:
return opener.status;
}
/* The thread responsible for hot-swapping filedisks. */
static VOID STDCALL WvFilediskHotSwapThread_(IN OUT WVL_SP_THREAD_ITEM item) {
LARGE_INTEGER timeout;
WVL_SP_THREAD thread = CONTAINING_RECORD(item, WVL_S_THREAD, Main);
WVL_SP_THREAD_ITEM work_item;
WV_SP_FILEDISK_HOT_SWAPPER_ info;
/* Wake up at least every 10 seconds. */
timeout.QuadPart = -100000000LL;
while (
(thread->State == WvlThreadStateStarted) ||
(thread->State == WvlThreadStateStopping)
) {
/* Wait for the work signal or the timeout. */
KeWaitForSingleObject(
&thread->Signal,
Executive,
KernelMode,
FALSE,
&timeout
);
work_item = WvlThreadGetItem(thread);
if (!work_item)
continue;
if (work_item->Func != WvFilediskHotSwapThread_) {
DBG("Unknown work item.\n");
continue;
}
info = CONTAINING_RECORD(
work_item,
WV_S_FILEDISK_HOT_SWAPPER_,
item[0]
);
/* Attempt a hot swap. */
if (WvFilediskHotSwap_(info->filedisk, info->filename)) {
/* Success. */
RtlFreeUnicodeString(info->filename);
wv_free(info);
} else {
/* Re-enqueue. */
WvlThreadAddItem(thread, info->item);
}
/* Reset the work signal. */
KeResetEvent(&thread->Signal);
} /* while thread is running. */
return;
}
/**
* Initiate a filedisk hot-swap to another file.
*
* @v filedisk The filedisk to be hot-swapped.
* @v file The ANSI filename for swapping to.
*/
VOID STDCALL WvFilediskHotSwap(IN WV_SP_FILEDISK_T filedisk, IN PCHAR file) {
static WVL_S_THREAD thread = {
/* Main */
{
/* Link */
{0},
/* Func */
WvFilediskHotSwapThread_,
},
/* State */
WvlThreadStateNotStarted,
};
WV_SP_FILEDISK_HOT_SWAPPER_ hot_swapper;
ANSI_STRING file_ansi;
NTSTATUS status;
hot_swapper = wv_malloc(sizeof *hot_swapper);
if (!hot_swapper) {
DBG("Non-critical: Couldn't allocate work item.\n");
return;
}
/* Build the Unicode string. */
RtlInitAnsiString(&file_ansi, file);
hot_swapper->filename->Buffer = NULL;
status = RtlAnsiStringToUnicodeString(
hot_swapper->filename,
&file_ansi,
TRUE
);
if (!NT_SUCCESS(status)) {
DBG("Non-critical: Couldn't allocate unicode string.\n");
wv_free(hot_swapper);
return;
}
/* Build the rest of the work item. */
hot_swapper->item->Func = WvFilediskHotSwapThread_;
hot_swapper->filedisk = filedisk;
/* Start the thread. If it's already been started, no matter. */
WvlThreadStart(&thread);
/* Add the hot-swapper work item. */
if (!WvlThreadAddItem(&thread, hot_swapper->item)) {
DBG("Non-critical: Couldn't add work item.\n");
RtlFreeUnicodeString(hot_swapper->filename);
wv_free(hot_swapper);
}
/* The thread is responsible for freeing the work item and file path. */
return;
}
/**
* Initiate a search for a GRUB4DOS backing disk.
*
* @v filedisk The filedisk whose backing disk we need.
*/
static BOOLEAN STDCALL WvFilediskG4dFindBackingDisk(
IN WV_SP_FILEDISK_T filedisk
) {
SP_WV_FILEDISK_G4D_FIND_BACKING_DISK finder;
KIRQL irql;
finder = wv_malloc(sizeof *finder);
if (!finder) {
DBG("Couldn't allocate work item!\n");
goto err_finder;
}
KeAcquireSpinLock(&WvFindDiskLock, &irql);
++WvFindDisk;
KeReleaseSpinLock(&WvFindDiskLock, irql);
finder->item->Func = WvFilediskG4dFindBackingDisk_;
finder->filedisk = filedisk;
/* Add the hot-swapper work item. */
if (!WvlThreadAddItem(filedisk->Thread, finder->item)) {
DBG("Couldn't add work item!\n");
goto err_work_item;
}
/* The thread is responsible for freeing the work item. */
return TRUE;
err_work_item:
KeAcquireSpinLock(&WvFindDiskLock, &irql);
--WvFindDisk;
KeReleaseSpinLock(&WvFindDiskLock, irql);
wv_free(finder);
err_finder:
return FALSE;
}
