diff --git a/compat/fsmonitor/fsm-listen-win32.c b/compat/fsmonitor/fsm-listen-win32.c index 5b928ab66e..4f46bd1d0a 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; @@ -34,6 +37,21 @@ 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 @@ -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; } @@ -98,6 +115,173 @@ 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"/.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"/" + * Note that the 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]); @@ -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); @@ -258,6 +462,62 @@ static void cancel_rdcw_watch(struct one_watch *watch) watch->is_active = FALSE; } +/* + * 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 "/.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"); + 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 * root directory. For a normal working directory, this includes @@ -274,6 +534,7 @@ static int process_worktree_events(struct fsmonitor_daemon_state *state) 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 +567,64 @@ 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; - strbuf_reset(&path); - if (normalize_path_in_utf8(info, &path) == -1) + 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; + } + + 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; + } + + 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; + } + } + +normalize_it: + if (normalize_path_in_utf8(wpath, wpath_len, &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); - } +process_it: + if (process_1_worktree_event(&cookie_list, &batch, &path, t, + info->Action)) + goto force_shutdown; skip_this_path: if (!info->NextEntryOffset) @@ -382,6 +653,9 @@ force_shutdown: * 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. + * + * Also, we do not care about shortnames within the external , since + * we never send these paths to clients. */ static int process_gitdir_events(struct fsmonitor_daemon_state *state) { @@ -403,8 +677,10 @@ 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); @@ -538,6 +814,8 @@ 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); diff --git a/t/t7527-builtin-fsmonitor.sh b/t/t7527-builtin-fsmonitor.sh index bd0c952a11..1be2178516 100755 --- a/t/t7527-builtin-fsmonitor.sh +++ b/t/t7527-builtin-fsmonitor.sh @@ -166,6 +166,71 @@ test_expect_success 'implicit daemon stop (rename .git)' ' test_must_fail git -C test_implicit_2 fsmonitor--daemon status ' +# File systems on Windows may or may not have shortnames. +# This is a volume-specific setting on modern systems. +# "C:/" drives are required to have them enabled. Other +# hard drives default to disabled. +# +# This is a crude test to see if shortnames are enabled +# on the volume containing the test directory. It is +# crude, but it does not require elevation like `fsutil`. +# +test_lazy_prereq SHORTNAMES ' + mkdir .foo && + test -d "FOO~1" +' + +# Here we assume that the shortname of ".git" is "GIT~1". +test_expect_success MINGW,SHORTNAMES 'implicit daemon stop (rename GIT~1)' ' + test_when_finished "stop_daemon_delete_repo test_implicit_1s" && + + git init test_implicit_1s && + + start_daemon -C test_implicit_1s && + + # renaming the .git directory will implicitly stop the daemon. + # this moves {.git, GIT~1} to {.gitxyz, GITXYZ~1}. + # the rename-from FS Event will contain the shortname. + # + mv test_implicit_1s/GIT~1 test_implicit_1s/.gitxyz && + + sleep 1 && + # put it back so that our status will not crawl out to our + # parent directory. + # this moves {.gitxyz, GITXYZ~1} to {.git, GIT~1}. + mv test_implicit_1s/.gitxyz test_implicit_1s/.git && + + test_must_fail git -C test_implicit_1s fsmonitor--daemon status +' + +# Here we first create a file with LONGNAME of "GIT~1" before +# we create the repo. This will cause the shortname of ".git" +# to be "GIT~2". +test_expect_success MINGW,SHORTNAMES 'implicit daemon stop (rename GIT~2)' ' + test_when_finished "stop_daemon_delete_repo test_implicit_1s2" && + + mkdir test_implicit_1s2 && + echo HELLO >test_implicit_1s2/GIT~1 && + git init test_implicit_1s2 && + + test_path_is_file test_implicit_1s2/GIT~1 && + test_path_is_dir test_implicit_1s2/GIT~2 && + + start_daemon -C test_implicit_1s2 && + + # renaming the .git directory will implicitly stop the daemon. + # the rename-from FS Event will contain the shortname. + # + mv test_implicit_1s2/GIT~2 test_implicit_1s2/.gitxyz && + + sleep 1 && + # put it back so that our status will not crawl out to our + # parent directory. + mv test_implicit_1s2/.gitxyz test_implicit_1s2/.git && + + test_must_fail git -C test_implicit_1s2 fsmonitor--daemon status +' + test_expect_success 'cannot start multiple daemons' ' test_when_finished "stop_daemon_delete_repo test_multiple" &&