diff options
Diffstat (limited to 'compat/fsmonitor/fsm-listen-win32.c')
-rw-r--r-- | compat/fsmonitor/fsm-listen-win32.c | 436 |
1 files changed, 362 insertions, 74 deletions
diff --git a/compat/fsmonitor/fsm-listen-win32.c b/compat/fsmonitor/fsm-listen-win32.c index 5b928ab..03df8d9 100644 --- a/compat/fsmonitor/fsm-listen-win32.c +++ b/compat/fsmonitor/fsm-listen-win32.c @@ -25,6 +25,9 @@ struct one_watch DWORD count; struct strbuf path; + wchar_t wpath_longname[MAX_PATH + 1]; + DWORD wpath_longname_len; + HANDLE hDir; HANDLE hEvent; OVERLAPPED overlapped; @@ -34,9 +37,24 @@ struct one_watch * need to later call GetOverlappedResult() and possibly CancelIoEx(). */ BOOL is_active; + + /* + * Are shortnames enabled on the containing drive? This is + * always true for "C:/" drives and usually never true for + * other drives. + * + * We only set this for the worktree because we only need to + * convert shortname paths to longname paths for items we send + * to clients. (We don't care about shortname expansion for + * paths inside a GITDIR because we never send them to + * clients.) + */ + BOOL has_shortnames; + BOOL has_tilde; + wchar_t dotgit_shortname[16]; /* for 8.3 name */ }; -struct fsmonitor_daemon_backend_data +struct fsm_listen_data { struct one_watch *watch_worktree; struct one_watch *watch_gitdir; @@ -51,17 +69,18 @@ struct fsmonitor_daemon_backend_data }; /* - * Convert the WCHAR path from the notification into UTF8 and - * then normalize it. + * Convert the WCHAR path from the event into UTF8 and normalize it. + * + * `wpath_len` is in WCHARS not bytes. */ -static int normalize_path_in_utf8(FILE_NOTIFY_INFORMATION *info, +static int normalize_path_in_utf8(wchar_t *wpath, DWORD wpath_len, struct strbuf *normalized_path) { int reserve; int len = 0; strbuf_reset(normalized_path); - if (!info->FileNameLength) + if (!wpath_len) goto normalize; /* @@ -70,12 +89,12 @@ static int normalize_path_in_utf8(FILE_NOTIFY_INFORMATION *info, * sequence of 2 UTF8 characters. That should let us * avoid ERROR_INSUFFICIENT_BUFFER 99.9+% of the time. */ - reserve = info->FileNameLength + 1; + reserve = 2 * wpath_len + 1; strbuf_grow(normalized_path, reserve); for (;;) { - len = WideCharToMultiByte(CP_UTF8, 0, info->FileName, - info->FileNameLength / sizeof(WCHAR), + len = WideCharToMultiByte(CP_UTF8, 0, + wpath, wpath_len, normalized_path->buf, strbuf_avail(normalized_path) - 1, NULL, NULL); @@ -83,9 +102,7 @@ static int normalize_path_in_utf8(FILE_NOTIFY_INFORMATION *info, 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); + GetLastError(), (int)wpath_len, wpath); return -1; } @@ -98,9 +115,176 @@ normalize: return strbuf_normalize_path(normalized_path); } +/* + * See if the worktree root directory has shortnames enabled. + * This will help us decide if we need to do an expensive shortname + * to longname conversion on every notification event. + * + * We do not want to create a file to test this, so we assume that the + * root directory contains a ".git" file or directory. (Our caller + * only calls us for the worktree root, so this should be fine.) + * + * Remember the spelling of the shortname for ".git" if it exists. + */ +static void check_for_shortnames(struct one_watch *watch) +{ + wchar_t buf_in[MAX_PATH + 1]; + wchar_t buf_out[MAX_PATH + 1]; + wchar_t *last; + wchar_t *p; + + /* build L"<wt-root-path>/.git" */ + swprintf(buf_in, ARRAY_SIZE(buf_in) - 1, L"%ls.git", + watch->wpath_longname); + + if (!GetShortPathNameW(buf_in, buf_out, ARRAY_SIZE(buf_out))) + return; + + /* + * Get the final filename component of the shortpath. + * We know that the path does not have a final slash. + */ + for (last = p = buf_out; *p; p++) + if (*p == L'/' || *p == '\\') + last = p + 1; + + if (!wcscmp(last, L".git")) + return; + + watch->has_shortnames = 1; + wcsncpy(watch->dotgit_shortname, last, + ARRAY_SIZE(watch->dotgit_shortname)); + + /* + * The shortname for ".git" is usually of the form "GIT~1", so + * we should be able to avoid shortname to longname mapping on + * every notification event if the source string does not + * contain a "~". + * + * However, the documentation for GetLongPathNameW() says + * that there are filesystems that don't follow that pattern + * and warns against this optimization. + * + * Lets test this. + */ + if (wcschr(watch->dotgit_shortname, L'~')) + watch->has_tilde = 1; +} + +enum get_relative_result { + GRR_NO_CONVERSION_NEEDED, + GRR_HAVE_CONVERSION, + GRR_SHUTDOWN, +}; + +/* + * Info notification paths are relative to the root of the watch. + * If our CWD is still at the root, then we can use relative paths + * to convert from shortnames to longnames. If our process has a + * different CWD, then we need to construct an absolute path, do + * the conversion, and then return the root-relative portion. + * + * We use the longname form of the root as our basis and assume that + * it already has a trailing slash. + * + * `wpath_len` is in WCHARS not bytes. + */ +static enum get_relative_result get_relative_longname( + struct one_watch *watch, + const wchar_t *wpath, DWORD wpath_len, + wchar_t *wpath_longname, size_t bufsize_wpath_longname) +{ + wchar_t buf_in[2 * MAX_PATH + 1]; + wchar_t buf_out[MAX_PATH + 1]; + DWORD root_len; + DWORD out_len; + + /* + * Build L"<wt-root-path>/<event-rel-path>" + * Note that the <event-rel-path> might not be null terminated + * so we avoid swprintf() constructions. + */ + root_len = watch->wpath_longname_len; + if (root_len + wpath_len >= ARRAY_SIZE(buf_in)) { + /* + * This should not happen. We cannot append the observed + * relative path onto the end of the worktree root path + * without overflowing the buffer. Just give up. + */ + return GRR_SHUTDOWN; + } + wcsncpy(buf_in, watch->wpath_longname, root_len); + wcsncpy(buf_in + root_len, wpath, wpath_len); + buf_in[root_len + wpath_len] = 0; + + /* + * We don't actually know if the source pathname is a + * shortname or a longname. This Windows routine allows + * either to be given as input. + */ + out_len = GetLongPathNameW(buf_in, buf_out, ARRAY_SIZE(buf_out)); + if (!out_len) { + /* + * The shortname to longname conversion can fail for + * various reasons, for example if the file has been + * deleted. (That is, if we just received a + * delete-file notification event and the file is + * already gone, we can't ask the file system to + * lookup the longname for it. Likewise, for moves + * and renames where we are given the old name.) + * + * Since deleting or moving a file or directory by its + * shortname is rather obscure, I'm going ignore the + * failure and ask the caller to report the original + * relative path. This seems kinder than failing here + * and forcing a resync. Besides, forcing a resync on + * every file/directory delete would effectively + * cripple monitoring. + * + * We might revisit this in the future. + */ + return GRR_NO_CONVERSION_NEEDED; + } + + if (!wcscmp(buf_in, buf_out)) { + /* + * The path does not have a shortname alias. + */ + return GRR_NO_CONVERSION_NEEDED; + } + + if (wcsncmp(buf_in, buf_out, root_len)) { + /* + * The spelling of the root directory portion of the computed + * longname has changed. This should not happen. Basically, + * it means that we don't know where (without recomputing the + * longname of just the root directory) to split out the + * relative path. Since this should not happen, I'm just + * going to let this fail and force a shutdown (because all + * subsequent events are probably going to see the same + * mismatch). + */ + return GRR_SHUTDOWN; + } + + if (out_len - root_len >= bufsize_wpath_longname) { + /* + * This should not happen. We cannot copy the root-relative + * portion of the path into the provided buffer without an + * overrun. Just give up. + */ + return GRR_SHUTDOWN; + } + + /* Return the worktree root-relative portion of the longname. */ + + wcscpy(wpath_longname, buf_out + root_len); + return GRR_HAVE_CONVERSION; +} + void fsm_listen__stop_async(struct fsmonitor_daemon_state *state) { - SetEvent(state->backend_data->hListener[LISTENER_SHUTDOWN]); + SetEvent(state->listen_data->hListener[LISTENER_SHUTDOWN]); } static struct one_watch *create_watch(struct fsmonitor_daemon_state *state, @@ -111,7 +295,9 @@ static struct one_watch *create_watch(struct fsmonitor_daemon_state *state, DWORD share_mode = FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE; HANDLE hDir; - wchar_t wpath[MAX_PATH]; + DWORD len_longname; + wchar_t wpath[MAX_PATH + 1]; + wchar_t wpath_longname[MAX_PATH + 1]; if (xutftowcs_path(wpath, path) < 0) { error(_("could not convert to wide characters: '%s'"), path); @@ -128,6 +314,21 @@ static struct one_watch *create_watch(struct fsmonitor_daemon_state *state, return NULL; } + len_longname = GetLongPathNameW(wpath, wpath_longname, + ARRAY_SIZE(wpath_longname)); + if (!len_longname) { + error(_("[GLE %ld] could not get longname of '%s'"), + GetLastError(), path); + CloseHandle(hDir); + return NULL; + } + + if (wpath_longname[len_longname - 1] != L'/' && + wpath_longname[len_longname - 1] != L'\\') { + wpath_longname[len_longname++] = L'/'; + wpath_longname[len_longname] = 0; + } + CALLOC_ARRAY(watch, 1); watch->buf_len = sizeof(watch->buffer); /* assume full MAX_RDCW_BUF */ @@ -135,6 +336,9 @@ static struct one_watch *create_watch(struct fsmonitor_daemon_state *state, strbuf_init(&watch->path, 0); strbuf_addstr(&watch->path, path); + wcscpy(watch->wpath_longname, wpath_longname); + watch->wpath_longname_len = len_longname; + watch->hDir = hDir; watch->hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); @@ -155,7 +359,7 @@ static void destroy_watch(struct one_watch *watch) free(watch); } -static int start_rdcw_watch(struct fsmonitor_daemon_backend_data *data, +static int start_rdcw_watch(struct fsm_listen_data *data, struct one_watch *watch) { DWORD dwNotifyFilter = @@ -220,12 +424,22 @@ static int recv_rdcw_watch(struct one_watch *watch) } /* - * NEEDSWORK: If an external <gitdir> is deleted, the above - * returns an error. I'm not sure that there's anything that - * we can do here other than failing -- the <worktree>/.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. + * GetOverlappedResult() fails if the watched directory is + * deleted while we were waiting for an overlapped IO to + * complete. The documentation did not list specific errors, + * but I observed ERROR_ACCESS_DENIED (0x05) errors during + * testing. + * + * Note that we only get notificaiton events for events + * *within* the directory, not *on* the directory itself. + * (These might be properies of the parent directory, for + * example). + * + * NEEDSWORK: We might try to check for the deleted directory + * case and return a better error message, but I'm not sure it + * is worth it. + * + * Shutdown if we get any error. */ error(_("GetOverlappedResult failed on '%s' [GLE %ld]"), @@ -259,6 +473,62 @@ static void cancel_rdcw_watch(struct one_watch *watch) } /* + * Process a single relative pathname event. + * Return 1 if we should shutdown. + */ +static int process_1_worktree_event( + struct string_list *cookie_list, + struct fsmonitor_batch **batch, + const struct strbuf *path, + enum fsmonitor_path_type t, + DWORD info_action) +{ + const char *slash; + + 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 "<worktree>/.git/" */ + break; + + case IS_DOT_GIT: + /* "<worktree>/.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"); + return 1; + } + 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); + } + + return 0; +} + +/* * Process filesystem events that happen anywhere (recursively) under the * <worktree> root directory. For a normal working directory, this includes * both version controlled files and the contents of the .git/ directory. @@ -268,12 +538,13 @@ static void cancel_rdcw_watch(struct one_watch *watch) */ static int process_worktree_events(struct fsmonitor_daemon_state *state) { - struct fsmonitor_daemon_backend_data *data = state->backend_data; + struct fsm_listen_data *data = state->listen_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; + wchar_t wpath_longname[MAX_PATH + 1]; /* * If the kernel gets more events than will fit in the kernel @@ -306,54 +577,64 @@ static int process_worktree_events(struct fsmonitor_daemon_state *state) */ for (;;) { FILE_NOTIFY_INFORMATION *info = (void *)p; - const char *slash; + wchar_t *wpath = info->FileName; + DWORD wpath_len = info->FileNameLength / sizeof(WCHAR); enum fsmonitor_path_type t; + enum get_relative_result grr; + + if (watch->has_shortnames) { + if (!wcscmp(wpath, watch->dotgit_shortname)) { + /* + * This event exactly matches the + * spelling of the shortname of + * ".git", so we can skip some steps. + * + * (This case is odd because the user + * can "rm -rf GIT~1" and we cannot + * use the filesystem to map it back + * to ".git".) + */ + strbuf_reset(&path); + strbuf_addstr(&path, ".git"); + t = IS_DOT_GIT; + goto process_it; + } - 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 "<worktree>/.git/" */ - break; + if (watch->has_tilde && !wcschr(wpath, L'~')) { + /* + * Shortnames on this filesystem have tildes + * and the notification path does not have + * one, so we assume that it is a longname. + */ + goto normalize_it; + } - case IS_DOT_GIT: - /* "<worktree>/.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"); + grr = get_relative_longname(watch, wpath, wpath_len, + wpath_longname, + ARRAY_SIZE(wpath_longname)); + switch (grr) { + case GRR_NO_CONVERSION_NEEDED: /* use info buffer as is */ + break; + case GRR_HAVE_CONVERSION: + wpath = wpath_longname; + wpath_len = wcslen(wpath); + break; + default: + case GRR_SHUTDOWN: 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; +normalize_it: + if (normalize_path_in_utf8(wpath, wpath_len, &path) == -1) + goto skip_this_path; - 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); - } + t = fsmonitor_classify_path_workdir_relative(path.buf); + +process_it: + if (process_1_worktree_event(&cookie_list, &batch, &path, t, + info->Action)) + goto force_shutdown; skip_this_path: if (!info->NextEntryOffset) @@ -382,10 +663,13 @@ force_shutdown: * Note that we DO NOT get filesystem events on the external <gitdir> * itself (it is not inside something that we are watching). In particular, * we do not get an event if the external <gitdir> is deleted. + * + * Also, we do not care about shortnames within the external <gitdir>, since + * we never send these paths to clients. */ static int process_gitdir_events(struct fsmonitor_daemon_state *state) { - struct fsmonitor_daemon_backend_data *data = state->backend_data; + struct fsm_listen_data *data = state->listen_data; struct one_watch *watch = data->watch_gitdir; struct strbuf path = STRBUF_INIT; struct string_list cookie_list = STRING_LIST_INIT_DUP; @@ -403,8 +687,10 @@ static int process_gitdir_events(struct fsmonitor_daemon_state *state) const char *slash; enum fsmonitor_path_type t; - strbuf_reset(&path); - if (normalize_path_in_utf8(info, &path) == -1) + if (normalize_path_in_utf8( + info->FileName, + info->FileNameLength / sizeof(WCHAR), + &path) == -1) goto skip_this_path; t = fsmonitor_classify_path_gitdir_relative(path.buf); @@ -441,11 +727,11 @@ skip_this_path: void fsm_listen__loop(struct fsmonitor_daemon_state *state) { - struct fsmonitor_daemon_backend_data *data = state->backend_data; + struct fsm_listen_data *data = state->listen_data; DWORD dwWait; int result; - state->error_code = 0; + state->listen_error_code = 0; if (start_rdcw_watch(data, data->watch_worktree) == -1) goto force_error_stop; @@ -510,7 +796,7 @@ void fsm_listen__loop(struct fsmonitor_daemon_state *state) } force_error_stop: - state->error_code = -1; + state->listen_error_code = -1; force_shutdown: /* @@ -527,7 +813,7 @@ clean_shutdown: int fsm_listen__ctor(struct fsmonitor_daemon_state *state) { - struct fsmonitor_daemon_backend_data *data; + struct fsm_listen_data *data; CALLOC_ARRAY(data, 1); @@ -538,6 +824,8 @@ int fsm_listen__ctor(struct fsmonitor_daemon_state *state) if (!data->watch_worktree) goto failed; + check_for_shortnames(data->watch_worktree); + if (state->nr_paths_watching > 1) { data->watch_gitdir = create_watch(state, state->path_gitdir_watch.buf); @@ -558,7 +846,7 @@ int fsm_listen__ctor(struct fsmonitor_daemon_state *state) data->nr_listener_handles++; } - state->backend_data = data; + state->listen_data = data; return 0; failed: @@ -571,16 +859,16 @@ failed: void fsm_listen__dtor(struct fsmonitor_daemon_state *state) { - struct fsmonitor_daemon_backend_data *data; + struct fsm_listen_data *data; - if (!state || !state->backend_data) + if (!state || !state->listen_data) return; - data = state->backend_data; + data = state->listen_data; CloseHandle(data->hEventShutdown); destroy_watch(data->watch_worktree); destroy_watch(data->watch_gitdir); - FREE_AND_NULL(state->backend_data); + FREE_AND_NULL(state->listen_data); } |