transmission/libtransmission/watchdir-win32.c

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/*
* This file Copyright (C) 2015-2016 Mnemosyne LLC
*
* It may be used under the GNU GPL versions 2 or 3
* or any future license endorsed by Mnemosyne LLC.
*
* $Id$
*/
#include <assert.h>
#include <errno.h>
#include <stddef.h> /* offsetof */
#include <stdlib.h> /* realloc () */
#include <process.h> /* _beginthreadex () */
#include <windows.h>
#include <event2/bufferevent.h>
#include <event2/event.h>
#include <event2/util.h>
#define __LIBTRANSMISSION_WATCHDIR_MODULE__
#include "transmission.h"
#include "log.h"
#include "net.h"
#include "utils.h"
#include "watchdir.h"
#include "watchdir-common.h"
/***
****
***/
#define log_error(...) (!tr_logLevelIsActive (TR_LOG_ERROR) ? (void) 0 : \
tr_logAddMessage (__FILE__, __LINE__, TR_LOG_ERROR, "watchdir:win32", __VA_ARGS__))
/***
****
***/
typedef struct tr_watchdir_win32
{
tr_watchdir_backend base;
HANDLE fd;
OVERLAPPED overlapped;
DWORD buffer[8 * 1024 / sizeof (DWORD)];
evutil_socket_t notify_pipe[2];
struct bufferevent * event;
HANDLE thread;
}
tr_watchdir_win32;
#define BACKEND_UPCAST(b) ((tr_watchdir_win32 *) (b))
#define WIN32_WATCH_MASK (FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_SIZE | FILE_NOTIFY_CHANGE_LAST_WRITE)
/***
****
***/
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static BOOL
tr_get_overlapped_result_ex (HANDLE handle,
LPOVERLAPPED overlapped,
LPDWORD bytes_transferred,
DWORD timeout,
BOOL alertable)
{
typedef BOOL (WINAPI * impl_t) (HANDLE, LPOVERLAPPED, LPDWORD, DWORD, BOOL);
static impl_t real_impl = NULL;
static bool is_real_impl_valid = false;
if (!is_real_impl_valid)
{
real_impl = (impl_t) GetProcAddress (GetModuleHandleW (L"kernel32.dll"),
"GetOverlappedResultEx");
is_real_impl_valid = true;
}
if (real_impl != NULL)
return real_impl (handle, overlapped, bytes_transferred, timeout, alertable);
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const DWORD wait_result = WaitForSingleObjectEx (handle, timeout, alertable);
if (wait_result == WAIT_FAILED)
return FALSE;
if (wait_result == WAIT_IO_COMPLETION || wait_result == WAIT_TIMEOUT)
{
SetLastError (wait_result);
return FALSE;
}
assert (wait_result == WAIT_OBJECT_0);
return GetOverlappedResult (handle, overlapped, bytes_transferred, FALSE);
}
static unsigned int __stdcall
tr_watchdir_win32_thread (void * context)
{
const tr_watchdir_t handle = context;
tr_watchdir_win32 * const backend = BACKEND_UPCAST (tr_watchdir_get_backend (handle));
DWORD bytes_transferred;
while (tr_get_overlapped_result_ex (backend->fd, &backend->overlapped, &bytes_transferred,
INFINITE, FALSE))
{
PFILE_NOTIFY_INFORMATION info = (PFILE_NOTIFY_INFORMATION) backend->buffer;
while (info->NextEntryOffset != 0)
*((BYTE **) &info) += info->NextEntryOffset;
info->NextEntryOffset = bytes_transferred - ((BYTE *) info - (BYTE *) backend->buffer);
send (backend->notify_pipe[1], (const char *) backend->buffer, bytes_transferred, 0);
if (!ReadDirectoryChangesW (backend->fd, backend->buffer, sizeof (backend->buffer), FALSE,
WIN32_WATCH_MASK, NULL, &backend->overlapped, NULL))
{
log_error ("Failed to read directory changes");
return 0;
}
}
if (GetLastError () != ERROR_OPERATION_ABORTED)
log_error ("Failed to wait for directory changes");
return 0;
}
static void
tr_watchdir_win32_on_first_scan (evutil_socket_t fd UNUSED,
short type UNUSED,
void * context)
{
const tr_watchdir_t handle = context;
tr_watchdir_scan (handle, NULL);
}
static void
tr_watchdir_win32_on_event (struct bufferevent * event,
void * context)
{
const tr_watchdir_t handle = context;
size_t nread;
size_t name_size = MAX_PATH * sizeof (WCHAR);
char * buffer = tr_malloc (sizeof (FILE_NOTIFY_INFORMATION) + name_size);
PFILE_NOTIFY_INFORMATION ev = (PFILE_NOTIFY_INFORMATION) buffer;
const size_t header_size = offsetof (FILE_NOTIFY_INFORMATION, FileName);
/* Read the size of the struct excluding name into buf. Guaranteed to have at
least sizeof (*ev) available */
while ((nread = bufferevent_read (event, ev, header_size)) != 0)
{
if (nread == (size_t) -1)
{
log_error ("Failed to read event: %s", tr_strerror (errno));
break;
}
if (nread != header_size)
{
log_error ("Failed to read event: expected %zu, got %zu bytes.",
header_size, nread);
break;
}
const size_t nleft = ev->NextEntryOffset - nread;
assert (ev->FileNameLength % sizeof (WCHAR) == 0);
assert (ev->FileNameLength > 0);
assert (ev->FileNameLength <= nleft);
if (nleft > name_size)
{
name_size = nleft;
buffer = tr_realloc (buffer, sizeof (FILE_NOTIFY_INFORMATION) + name_size);
ev = (PFILE_NOTIFY_INFORMATION) buffer;
}
/* Consume entire name into buffer */
if ((nread = bufferevent_read (event, buffer + header_size, nleft)) == (size_t) -1)
{
log_error ("Failed to read name: %s", tr_strerror (errno));
break;
}
if (nread != nleft)
{
log_error ("Failed to read name: expected %zu, got %zu bytes.", nleft, nread);
break;
}
if (ev->Action == FILE_ACTION_ADDED ||
ev->Action == FILE_ACTION_MODIFIED ||
ev->Action == FILE_ACTION_RENAMED_NEW_NAME)
{
char * name = tr_win32_native_to_utf8 (ev->FileName,
ev->FileNameLength / sizeof (WCHAR));
if (name != NULL)
{
tr_watchdir_process (handle, name);
tr_free (name);
}
}
}
tr_free (buffer);
}
static void
tr_watchdir_win32_free (tr_watchdir_backend * backend_base)
{
tr_watchdir_win32 * const backend = BACKEND_UPCAST (backend_base);
if (backend == NULL)
return;
assert (backend->base.free_func == &tr_watchdir_win32_free);
if (backend->fd != INVALID_HANDLE_VALUE)
CancelIoEx (backend->fd, &backend->overlapped);
if (backend->thread != NULL)
{
WaitForSingleObject (backend->thread, INFINITE);
CloseHandle (backend->thread);
}
if (backend->event != NULL)
bufferevent_free (backend->event);
if (backend->notify_pipe[0] != TR_BAD_SOCKET)
evutil_closesocket (backend->notify_pipe[0]);
if (backend->notify_pipe[1] != TR_BAD_SOCKET)
evutil_closesocket (backend->notify_pipe[1]);
if (backend->fd != INVALID_HANDLE_VALUE)
CloseHandle (backend->fd);
tr_free (backend);
}
tr_watchdir_backend *
tr_watchdir_win32_new (tr_watchdir_t handle)
{
const char * const path = tr_watchdir_get_path (handle);
wchar_t * wide_path;
tr_watchdir_win32 * backend;
backend = tr_new0 (tr_watchdir_win32, 1);
backend->base.free_func = &tr_watchdir_win32_free;
backend->fd = INVALID_HANDLE_VALUE;
backend->notify_pipe[0] = backend->notify_pipe[1] = TR_BAD_SOCKET;
if ((wide_path = tr_win32_utf8_to_native (path, -1)) == NULL)
{
log_error ("Failed to convert \"%s\" to native path", path);
goto fail;
}
if ((backend->fd = CreateFileW (wide_path, FILE_LIST_DIRECTORY,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
NULL, OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
NULL)) == INVALID_HANDLE_VALUE)
{
log_error ("Failed to open directory \"%s\"", path);
goto fail;
}
tr_free (wide_path);
wide_path = NULL;
backend->overlapped.Pointer = handle;
if (!ReadDirectoryChangesW (backend->fd, backend->buffer, sizeof (backend->buffer), FALSE,
WIN32_WATCH_MASK, NULL, &backend->overlapped, NULL))
{
log_error ("Failed to read directory changes");
goto fail;
}
if (evutil_socketpair (AF_INET, SOCK_STREAM, 0, backend->notify_pipe) == -1)
{
log_error ("Failed to create notify pipe: %s", tr_strerror (errno));
goto fail;
}
if ((backend->event = bufferevent_socket_new (tr_watchdir_get_event_base (handle),
backend->notify_pipe[0], 0)) == NULL)
{
log_error ("Failed to create event buffer: %s", tr_strerror (errno));
goto fail;
}
bufferevent_setwatermark (backend->event, EV_READ, sizeof (FILE_NOTIFY_INFORMATION), 0);
bufferevent_setcb (backend->event, &tr_watchdir_win32_on_event, NULL, NULL, handle);
bufferevent_enable (backend->event, EV_READ);
if ((backend->thread = (HANDLE) _beginthreadex (NULL, 0, &tr_watchdir_win32_thread,
handle, 0, NULL)) == NULL)
{
log_error ("Failed to create thread");
goto fail;
}
/* Perform an initial scan on the directory */
if (event_base_once (tr_watchdir_get_event_base (handle), -1, EV_TIMEOUT,
&tr_watchdir_win32_on_first_scan, handle, NULL) == -1)
log_error ("Failed to perform initial scan: %s", tr_strerror (errno));
return BACKEND_DOWNCAST (backend);
fail:
tr_watchdir_win32_free (BACKEND_DOWNCAST (backend));
tr_free (wide_path);
return NULL;
}
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