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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.
*
*/
#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 "tr-assert.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)
/***
****
***/
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);
}
DWORD const 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;
}
TR_ASSERT(wait_result == WAIT_OBJECT_0);
return GetOverlappedResult(handle, overlapped, bytes_transferred, FALSE);
}
static unsigned int __stdcall tr_watchdir_win32_thread(void* context)
{
tr_watchdir_t const 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], (char const*)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)
{
tr_watchdir_t const handle = context;
tr_watchdir_scan(handle, NULL);
}
static void tr_watchdir_win32_on_event(struct bufferevent* event, void* context)
{
tr_watchdir_t const 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;
size_t const 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;
}
size_t const nleft = ev->NextEntryOffset - nread;
TR_ASSERT(ev->FileNameLength % sizeof(WCHAR) == 0);
TR_ASSERT(ev->FileNameLength > 0);
TR_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;
}
TR_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)
{
char const* 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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