From patchwork Sat May 22 13:56:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Hostetler X-Patchwork-Id: 12274575 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F359C4707E for ; Sat, 22 May 2021 13:57:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F3563610A6 for ; Sat, 22 May 2021 13:57:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231316AbhEVN7C (ORCPT ); Sat, 22 May 2021 09:59:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231264AbhEVN6s (ORCPT ); Sat, 22 May 2021 09:58:48 -0400 Received: from mail-wm1-x336.google.com (mail-wm1-x336.google.com [IPv6:2a00:1450:4864:20::336]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C26A4C061574 for ; Sat, 22 May 2021 06:57:22 -0700 (PDT) Received: by mail-wm1-x336.google.com with SMTP id u4-20020a05600c00c4b02901774b80945cso8907948wmm.3 for ; Sat, 22 May 2021 06:57:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=2qfjyHGIj/ecIh92BpHHOx2mYJyFmHMDkPjRilrpnY0=; b=WfxxEXMDqQ0kYuy2MUmtp+HJTkSnB4X+7WazK/MC0s/iXFuofiTK/UVG9zdEq79Tbf OzQ+omrUj5ws9HyntHX3dt2Vu1TgSx2F7l6hcLUvDfL07JtjKZPiyjY+3Cc827hnfxFY sQ6i5NiW3oLIo66Koj8/B7cj/N+BxvXU1mZb7awfyGGcrS+R0kwYZV9jBnz8Fwnz8ULH IZ+3qC4L26CeQ//vIOnD1tsbjYtNKiOepD1mm/ugt57nfMXzkhn2fJ5eaFOMSlPs0kXL xL4FyJCgZBZa47hllYW8x/4sDPg3mJzjEnAsk9g+T669jxeuzszazg0JFKcVVeW66lU5 w46w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=2qfjyHGIj/ecIh92BpHHOx2mYJyFmHMDkPjRilrpnY0=; b=DsAcbdX2werlRgjfgCQIyF0puCrcrxEEzSKTF0varKJuaTtZmRCmqDGBrPgCGoN684 3nHVs8JtXnhqhzz8+oLxH/qYaEUUYA8U0/SlyoNHpw50jPvQ6BZ9EaMRxavEZaM8lodE kCNoaL6beqhgaVnzBK16BAhnPe23YwI0X6L/wIhC0jIIX/+6MrxBfihnEBJP4r99KgD/ QIsEEhfDZxFJdXoYxZFulYzrp0NEfxVoUk31YNW3u/G88DtqEbtCDJgXwqgvkll76w7a jgcOPJJMhSJeLTuCiyCUIxToNJ3N7iKhuv5WcIwMaCP0kWUla7blYnzGpVj0BpUX83yg 8tMQ== X-Gm-Message-State: AOAM5319EL+WBO5nGmk76RYrgO2TPNyttwiBDos/5DU/eDw/ZSxAqQL4 pOTmq5QWU5+rBcguZtBD0eHQ0u1dPQo= X-Google-Smtp-Source: ABdhPJz9REhYd8PLYkKvU1Y1psbcFkVuhX5BwHAzheW3qBII28NmcPX/KXEoDGk5sNAsej/r/M2Nsg== X-Received: by 2002:a7b:cc83:: with SMTP id p3mr13301046wma.169.1621691841309; Sat, 22 May 2021 06:57:21 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id o129sm2620892wmo.22.2021.05.22.06.57.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 22 May 2021 06:57:20 -0700 (PDT) Message-Id: <9ea4b04b8215b1e397623ea4c63e6af3655c74d3.1621691828.git.gitgitgadget@gmail.com> In-Reply-To: References: Date: Sat, 22 May 2021 13:56:56 +0000 Subject: [PATCH v2 17/28] fsmonitor-fs-listen-win32: implement FSMonitor backend on Windows Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: Johannes Schindelin , Jeff Hostetler , Derrick Stolee , Jeff Hostetler , Jeff Hostetler Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Jeff Hostetler From: Jeff Hostetler Teach the win32 backend to register a watch on the working tree root directory (recursively). Also watch the if it is not inside the working tree. And to collect path change notifications into batches and publish. Signed-off-by: Jeff Hostetler --- compat/fsmonitor/fsmonitor-fs-listen-win32.c | 532 +++++++++++++++++++ 1 file changed, 532 insertions(+) diff --git a/compat/fsmonitor/fsmonitor-fs-listen-win32.c b/compat/fsmonitor/fsmonitor-fs-listen-win32.c index 880446b49e35..ba087b292df6 100644 --- a/compat/fsmonitor/fsmonitor-fs-listen-win32.c +++ b/compat/fsmonitor/fsmonitor-fs-listen-win32.c @@ -2,20 +2,552 @@ #include "config.h" #include "fsmonitor.h" #include "fsmonitor-fs-listen.h" +#include "fsmonitor--daemon.h" + +/* + * The documentation of ReadDirectoryChangesW() states that the maximum + * buffer size is 64K when the monitored directory is remote. + * + * Larger buffers may be used when the monitored directory is local and + * will help us receive events faster from the kernel and avoid dropped + * events. + * + * So we try to use a very large buffer and silently fallback to 64K if + * we get an error. + */ +#define MAX_RDCW_BUF_FALLBACK (65536) +#define MAX_RDCW_BUF (65536 * 8) + +struct one_watch +{ + char buffer[MAX_RDCW_BUF]; + DWORD buf_len; + DWORD count; + + struct strbuf path; + HANDLE hDir; + HANDLE hEvent; + OVERLAPPED overlapped; + + /* + * Is there an active ReadDirectoryChangesW() call pending. If so, we + * need to later call GetOverlappedResult() and possibly CancelIoEx(). + */ + BOOL is_active; +}; + +struct fsmonitor_daemon_backend_data +{ + struct one_watch *watch_worktree; + struct one_watch *watch_gitdir; + + HANDLE hEventShutdown; + + HANDLE hListener[3]; /* we don't own these handles */ +#define LISTENER_SHUTDOWN 0 +#define LISTENER_HAVE_DATA_WORKTREE 1 +#define LISTENER_HAVE_DATA_GITDIR 2 + int nr_listener_handles; +}; + +/* + * Convert the WCHAR path from the notification into UTF8 and + * then normalize it. + */ +static int normalize_path_in_utf8(FILE_NOTIFY_INFORMATION *info, + struct strbuf *normalized_path) +{ + int reserve; + int len = 0; + + strbuf_reset(normalized_path); + if (!info->FileNameLength) + goto normalize; + + /* + * Pre-reserve enough space in the UTF8 buffer for + * each Unicode WCHAR character to be mapped into a + * sequence of 2 UTF8 characters. That should let us + * avoid ERROR_INSUFFICIENT_BUFFER 99.9+% of the time. + */ + reserve = info->FileNameLength + 1; + strbuf_grow(normalized_path, reserve); + + for (;;) { + len = WideCharToMultiByte(CP_UTF8, 0, info->FileName, + info->FileNameLength / sizeof(WCHAR), + normalized_path->buf, + strbuf_avail(normalized_path) - 1, + NULL, NULL); + if (len > 0) + goto normalize; + if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) { + error("[GLE %ld] could not convert path to UTF-8: '%.*ls'", + GetLastError(), + (int)(info->FileNameLength / sizeof(WCHAR)), + info->FileName); + return -1; + } + + strbuf_grow(normalized_path, + strbuf_avail(normalized_path) + reserve); + } + +normalize: + strbuf_setlen(normalized_path, len); + return strbuf_normalize_path(normalized_path); +} void fsmonitor_fs_listen__stop_async(struct fsmonitor_daemon_state *state) { + SetEvent(state->backend_data->hListener[LISTENER_SHUTDOWN]); +} + +static struct one_watch *create_watch(struct fsmonitor_daemon_state *state, + const char *path) +{ + struct one_watch *watch = NULL; + DWORD desired_access = FILE_LIST_DIRECTORY; + DWORD share_mode = + FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE; + HANDLE hDir; + + hDir = CreateFileA(path, + desired_access, share_mode, NULL, OPEN_EXISTING, + FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED, + NULL); + if (hDir == INVALID_HANDLE_VALUE) { + error(_("[GLE %ld] could not watch '%s'"), + GetLastError(), path); + return NULL; + } + + CALLOC_ARRAY(watch, 1); + + watch->buf_len = sizeof(watch->buffer); /* assume full MAX_RDCW_BUF */ + + strbuf_init(&watch->path, 0); + strbuf_addstr(&watch->path, path); + + watch->hDir = hDir; + watch->hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); + + return watch; +} + +static void destroy_watch(struct one_watch *watch) +{ + if (!watch) + return; + + strbuf_release(&watch->path); + if (watch->hDir != INVALID_HANDLE_VALUE) + CloseHandle(watch->hDir); + if (watch->hEvent != INVALID_HANDLE_VALUE) + CloseHandle(watch->hEvent); + + free(watch); +} + +static int start_rdcw_watch(struct fsmonitor_daemon_backend_data *data, + struct one_watch *watch) +{ + DWORD dwNotifyFilter = + FILE_NOTIFY_CHANGE_FILE_NAME | + FILE_NOTIFY_CHANGE_DIR_NAME | + FILE_NOTIFY_CHANGE_ATTRIBUTES | + FILE_NOTIFY_CHANGE_SIZE | + FILE_NOTIFY_CHANGE_LAST_WRITE | + FILE_NOTIFY_CHANGE_CREATION; + + ResetEvent(watch->hEvent); + + memset(&watch->overlapped, 0, sizeof(watch->overlapped)); + watch->overlapped.hEvent = watch->hEvent; + +start_watch: + /* + * Queue an async call using Overlapped IO. This returns immediately. + * Our event handle will be signalled when the real result is available. + * + * The return value here just means that we successfully queued it. + * We won't know if the Read...() actually produces data until later. + */ + watch->is_active = ReadDirectoryChangesW( + watch->hDir, watch->buffer, watch->buf_len, TRUE, + dwNotifyFilter, &watch->count, &watch->overlapped, NULL); + + /* + * The kernel throws an invalid parameter error when our buffer + * is too big and we are pointed at a remote directory (and possibly + * for other reasons). Quietly set it down and try again. + * + * See note about MAX_RDCW_BUF at the top. + */ + if (!watch->is_active && + GetLastError() == ERROR_INVALID_PARAMETER && + watch->buf_len > MAX_RDCW_BUF_FALLBACK) { + watch->buf_len = MAX_RDCW_BUF_FALLBACK; + goto start_watch; + } + + if (watch->is_active) + return 0; + + error("ReadDirectoryChangedW failed on '%s' [GLE %ld]", + watch->path.buf, GetLastError()); + return -1; +} + +static int recv_rdcw_watch(struct one_watch *watch) +{ + watch->is_active = FALSE; + + /* + * The overlapped result is ready. If the Read...() was successful + * we finally receive the actual result into our buffer. + */ + if (GetOverlappedResult(watch->hDir, &watch->overlapped, &watch->count, + TRUE)) + return 0; + + /* + * NEEDSWORK: If an external is deleted, the above + * returns an error. I'm not sure that there's anything that + * we can do here other than failing -- the /.git + * link file would be broken anyway. We might try to check + * for that and return a better error message, but I'm not + * sure it is worth it. + */ + + error("GetOverlappedResult failed on '%s' [GLE %ld]", + watch->path.buf, GetLastError()); + return -1; +} + +static void cancel_rdcw_watch(struct one_watch *watch) +{ + DWORD count; + + if (!watch || !watch->is_active) + return; + + /* + * The calls to ReadDirectoryChangesW() and GetOverlappedResult() + * form a "pair" (my term) where we queue an IO and promise to + * hang around and wait for the kernel to give us the result. + * + * If for some reason after we queue the IO, we have to quit + * or otherwise not stick around for the second half, we must + * tell the kernel to abort the IO. This prevents the kernel + * from writing to our buffer and/or signalling our event + * after we free them. + * + * (Ask me how much fun it was to track that one down). + */ + CancelIoEx(watch->hDir, &watch->overlapped); + GetOverlappedResult(watch->hDir, &watch->overlapped, &count, TRUE); + watch->is_active = FALSE; +} + +/* + * Process filesystem events that happen anywhere (recursively) under the + * root directory. For a normal working directory, this includes + * both version controlled files and the contents of the .git/ directory. + * + * If /.git is a file, then we only see events for the file + * itself. + */ +static int process_worktree_events(struct fsmonitor_daemon_state *state) +{ + struct fsmonitor_daemon_backend_data *data = state->backend_data; + struct one_watch *watch = data->watch_worktree; + struct strbuf path = STRBUF_INIT; + struct string_list cookie_list = STRING_LIST_INIT_DUP; + struct fsmonitor_batch *batch = NULL; + const char *p = watch->buffer; + + /* + * If the kernel gets more events than will fit in the kernel + * buffer associated with our RDCW handle, it drops them and + * returns a count of zero. + * + * Yes, the call returns WITHOUT error and with length zero. + * + * (The "overflow" case is not ambiguous with the "no data" case + * because we did an INFINITE wait.) + * + * This means we have a gap in coverage. Tell the daemon layer + * to resync. + */ + if (!watch->count) { + trace2_data_string("fsmonitor", NULL, "fsm-listen/kernel", + "overflow"); + fsmonitor_force_resync(state); + return LISTENER_HAVE_DATA_WORKTREE; + } + + /* + * On Windows, `info` contains an "array" of paths that are + * relative to the root of whichever directory handle received + * the event. + */ + for (;;) { + FILE_NOTIFY_INFORMATION *info = (void *)p; + const char *slash; + enum fsmonitor_path_type t; + + strbuf_reset(&path); + if (normalize_path_in_utf8(info, &path) == -1) + goto skip_this_path; + + t = fsmonitor_classify_path_workdir_relative(path.buf); + + switch (t) { + case IS_INSIDE_DOT_GIT_WITH_COOKIE_PREFIX: + /* special case cookie files within .git */ + + /* Use just the filename of the cookie file. */ + slash = find_last_dir_sep(path.buf); + string_list_append(&cookie_list, + slash ? slash + 1 : path.buf); + break; + + case IS_INSIDE_DOT_GIT: + /* ignore everything inside of "/.git/" */ + break; + + case IS_DOT_GIT: + /* "/.git" was deleted (or renamed away) */ + if ((info->Action == FILE_ACTION_REMOVED) || + (info->Action == FILE_ACTION_RENAMED_OLD_NAME)) { + trace2_data_string("fsmonitor", NULL, + "fsm-listen/dotgit", + "removed"); + goto force_shutdown; + } + break; + + case IS_WORKDIR_PATH: + /* queue normal pathname */ + if (!batch) + batch = fsmonitor_batch__new(); + fsmonitor_batch__add_path(batch, path.buf); + break; + + case IS_GITDIR: + case IS_INSIDE_GITDIR: + case IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX: + default: + BUG("unexpected path classification '%d' for '%s'", + t, path.buf); + } + +skip_this_path: + if (!info->NextEntryOffset) + break; + p += info->NextEntryOffset; + } + + fsmonitor_publish(state, batch, &cookie_list); + batch = NULL; + string_list_clear(&cookie_list, 0); + strbuf_release(&path); + return LISTENER_HAVE_DATA_WORKTREE; + +force_shutdown: + fsmonitor_batch__pop(batch); + string_list_clear(&cookie_list, 0); + strbuf_release(&path); + return LISTENER_SHUTDOWN; +} + +/* + * Process filesystem events that happened anywhere (recursively) under the + * external (such as non-primary worktrees or submodules). + * We only care about cookie files that our client threads created here. + * + * Note that we DO NOT get filesystem events on the external + * itself (it is not inside something that we are watching). In particular, + * we do not get an event if the external is deleted. + */ +static int process_gitdir_events(struct fsmonitor_daemon_state *state) +{ + struct fsmonitor_daemon_backend_data *data = state->backend_data; + struct one_watch *watch = data->watch_gitdir; + struct strbuf path = STRBUF_INIT; + struct string_list cookie_list = STRING_LIST_INIT_DUP; + const char *p = watch->buffer; + + if (!watch->count) { + trace2_data_string("fsmonitor", NULL, "fsm-listen/kernel", + "overflow"); + fsmonitor_force_resync(state); + return LISTENER_HAVE_DATA_GITDIR; + } + + for (;;) { + FILE_NOTIFY_INFORMATION *info = (void *)p; + const char *slash; + enum fsmonitor_path_type t; + + strbuf_reset(&path); + if (normalize_path_in_utf8(info, &path) == -1) + goto skip_this_path; + + t = fsmonitor_classify_path_gitdir_relative(path.buf); + + trace_printf_key(&trace_fsmonitor, "BBB: %s", path.buf); + + switch (t) { + case IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX: + /* special case cookie files within gitdir */ + + /* Use just the filename of the cookie file. */ + slash = find_last_dir_sep(path.buf); + string_list_append(&cookie_list, + slash ? slash + 1 : path.buf); + break; + + case IS_INSIDE_GITDIR: + goto skip_this_path; + + default: + BUG("unexpected path classification '%d' for '%s'", + t, path.buf); + } + +skip_this_path: + if (!info->NextEntryOffset) + break; + p += info->NextEntryOffset; + } + + fsmonitor_publish(state, NULL, &cookie_list); + string_list_clear(&cookie_list, 0); + strbuf_release(&path); + return LISTENER_HAVE_DATA_GITDIR; } void fsmonitor_fs_listen__loop(struct fsmonitor_daemon_state *state) { + struct fsmonitor_daemon_backend_data *data = state->backend_data; + DWORD dwWait; + + state->error_code = 0; + + if (start_rdcw_watch(data, data->watch_worktree) == -1) + goto force_error_stop; + + if (data->watch_gitdir && + start_rdcw_watch(data, data->watch_gitdir) == -1) + goto force_error_stop; + + for (;;) { + dwWait = WaitForMultipleObjects(data->nr_listener_handles, + data->hListener, + FALSE, INFINITE); + + if (dwWait == WAIT_OBJECT_0 + LISTENER_HAVE_DATA_WORKTREE) { + if (recv_rdcw_watch(data->watch_worktree) == -1) + goto force_error_stop; + if (process_worktree_events(state) == LISTENER_SHUTDOWN) + goto force_shutdown; + if (start_rdcw_watch(data, data->watch_worktree) == -1) + goto force_error_stop; + continue; + } + + if (dwWait == WAIT_OBJECT_0 + LISTENER_HAVE_DATA_GITDIR) { + if (recv_rdcw_watch(data->watch_gitdir) == -1) + goto force_error_stop; + if (process_gitdir_events(state) == LISTENER_SHUTDOWN) + goto force_shutdown; + if (start_rdcw_watch(data, data->watch_gitdir) == -1) + goto force_error_stop; + continue; + } + + if (dwWait == WAIT_OBJECT_0 + LISTENER_SHUTDOWN) + goto clean_shutdown; + + error(_("could not read directory changes [GLE %ld]"), + GetLastError()); + goto force_error_stop; + } + +force_error_stop: + state->error_code = -1; + +force_shutdown: + /* + * Tell the IPC thead pool to stop (which completes the await + * in the main thread (which will also signal this thread (if + * we are still alive))). + */ + ipc_server_stop_async(state->ipc_server_data); + +clean_shutdown: + cancel_rdcw_watch(data->watch_worktree); + cancel_rdcw_watch(data->watch_gitdir); } int fsmonitor_fs_listen__ctor(struct fsmonitor_daemon_state *state) { + struct fsmonitor_daemon_backend_data *data; + + CALLOC_ARRAY(data, 1); + + data->hEventShutdown = CreateEvent(NULL, TRUE, FALSE, NULL); + + data->watch_worktree = create_watch(state, + state->path_worktree_watch.buf); + if (!data->watch_worktree) + goto failed; + + if (state->nr_paths_watching > 1) { + data->watch_gitdir = create_watch(state, + state->path_gitdir_watch.buf); + if (!data->watch_gitdir) + goto failed; + } + + data->hListener[LISTENER_SHUTDOWN] = data->hEventShutdown; + data->nr_listener_handles++; + + data->hListener[LISTENER_HAVE_DATA_WORKTREE] = + data->watch_worktree->hEvent; + data->nr_listener_handles++; + + if (data->watch_gitdir) { + data->hListener[LISTENER_HAVE_DATA_GITDIR] = + data->watch_gitdir->hEvent; + data->nr_listener_handles++; + } + + state->backend_data = data; + return 0; + +failed: + CloseHandle(data->hEventShutdown); + destroy_watch(data->watch_worktree); + destroy_watch(data->watch_gitdir); + return -1; } void fsmonitor_fs_listen__dtor(struct fsmonitor_daemon_state *state) { + struct fsmonitor_daemon_backend_data *data; + + if (!state || !state->backend_data) + return; + + data = state->backend_data; + + CloseHandle(data->hEventShutdown); + destroy_watch(data->watch_worktree); + destroy_watch(data->watch_gitdir); + + FREE_AND_NULL(state->backend_data); }