From patchwork Wed Sep 28 20:12:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric DeCosta X-Patchwork-Id: 12992880 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E240C04A95 for ; Wed, 28 Sep 2022 20:12:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232666AbiI1UMc (ORCPT ); Wed, 28 Sep 2022 16:12:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232792AbiI1UMV (ORCPT ); Wed, 28 Sep 2022 16:12:21 -0400 Received: from mail-wr1-x429.google.com (mail-wr1-x429.google.com [IPv6:2a00:1450:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79B0AA2860 for ; Wed, 28 Sep 2022 13:12:19 -0700 (PDT) Received: by mail-wr1-x429.google.com with SMTP id h7so9041870wru.10 for ; Wed, 28 Sep 2022 13:12:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:mime-version:content-transfer-encoding:fcc:subject:date:from :references:in-reply-to:message-id:from:to:cc:subject:date; bh=DZpanFj0dNUjZQxjvNY6Z35aXmsd7rFp9sQ9vNKP1oo=; b=eZ//Zsn4meXJqIY/v8WMDrCrfGJPxiOJemDgUzuQWDjYR5A5obii1cxpmLYfi0P1+d EARvnYFa31MzlnImTAeEQnA79W0dApXjqx2dHpIDv0pl6QA3n83Hn1G+36WBXqVvxZ3r 4tj2GmQ3JyquRHqmF8CJvAPsXDe3cdwb1QWiQ9g8j7O6AfknriFIzSpHk5rww7gIz+3b +OPEOG3/bJc1iWfc212pJx29IROzMmejRCzBFs9KRwAvDCo5ROapNLo0KmBnT8G3ew1h bThpXbS+OSUw+SRMCLgGt/w0Vt9DLq1ZMN+hx7qdw8xP+ukJ1aH1YAG1RTj8Fh2y+5f/ MMkw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:mime-version:content-transfer-encoding:fcc:subject:date:from :references:in-reply-to:message-id:x-gm-message-state:from:to:cc :subject:date; bh=DZpanFj0dNUjZQxjvNY6Z35aXmsd7rFp9sQ9vNKP1oo=; b=R6dwaWVMMHZe2mWqxPmF+ErWJzM2UkHE0r7zuhtRlCDoO7LQuTajizkyxhGraN0jsr K80Y6TObOkb0VbffEkuX582Ah6VnpY0hVyUZfmmCatM3QlfrgYp9Aa3wQthObb5xE6G1 LyCjIBYEc7Tm4AAz5mfLM1+SQf0u9LsLwvhTPCXJgQvoYKxDndRRI78795mXe+lRR5Wv uxkhp42EPPY+52fU2xR0Hf8X8RoG2roNKi9e0zoac1KabXBtJpaeSoFmPtxUaiOXnvlT k3LtejfG1bQid1Sag0DvIqMuOkarZMc8czdccEjtEoj1+HmSOvXMtHziT2Zevwdtqxhd anyQ== X-Gm-Message-State: ACrzQf1PJCANbzORHjo/hHk1f7mrDCQ9odBNxAumsOXLRF73ihfCr2gu d0ZGUfHswA7QzcC0hxgqB7QU8etvhTo= X-Google-Smtp-Source: AMsMyM5BAJ4IJ6Pu0eZKUpaDjWGeBCXXqv4O9TaIjKcST1FVF+xlkTEXmdzK9vkniIyV3xKPGvDO2w== X-Received: by 2002:a5d:648c:0:b0:22a:2c04:97a5 with SMTP id o12-20020a5d648c000000b0022a2c0497a5mr22064075wri.326.1664395937655; Wed, 28 Sep 2022 13:12:17 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id l18-20020a05600c1d1200b003a601a1c2f7sm2722617wms.19.2022.09.28.13.12.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Sep 2022 13:12:17 -0700 (PDT) Message-Id: <241043b7c151b8c85b37dd3aceb3a00f58a14aac.1664395931.git.gitgitgadget@gmail.com> In-Reply-To: References: Date: Wed, 28 Sep 2022 20:12:09 +0000 Subject: [PATCH v14 4/6] fsmonitor: deal with synthetic firmlinks on macOS Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: Jeff Hostetler , Eric Sunshine , Torsten =?utf-8?q?B=C3=B6gershause?= =?utf-8?q?n?= , =?utf-8?b?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason , Ramsay Jones , Johannes Schindelin , Eric DeCosta , Eric DeCosta Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Eric DeCosta From: Eric DeCosta Starting with macOS 10.15 (Catalina), Apple introduced a new feature called 'firmlinks' in order to separate the boot volume into two volumes, one read-only and one writable but still present them to the user as a single volume. Along with this change, Apple removed the ability to create symlinks in the root directory and replaced them with 'synthetic firmlinks'. See 'man synthetic.conf' When FSEevents reports the path of changed files, if the path involves a synthetic firmlink, the path is reported from the point of the synthetic firmlink and not the real path. For example: Real path: /System/Volumes/Data/network/working/directory/foo.txt Synthetic firmlink: /network -> /System/Volumes/Data/network FSEvents path: /network/working/directory/foo.txt This causes the FSEvents path to not match against the worktree directory. There are several ways in which synthetic firmlinks can be created: they can be defined in /etc/synthetic.conf, the automounter can create them, and there may be other means. Simply reading /etc/synthetic.conf is insufficient. No matter what process creates synthetic firmlinks, they all get created in the root directory. Therefore, in order to deal with synthetic firmlinks, the root directory is scanned and the first possible synthetic firmink that, when resolved, is a prefix of the worktree is used to map FSEvents paths to worktree paths. Signed-off-by: Eric DeCosta --- builtin/fsmonitor--daemon.c | 8 +++ compat/fsmonitor/fsm-listen-darwin.c | 14 +++- compat/fsmonitor/fsm-path-utils-darwin.c | 92 ++++++++++++++++++++++++ compat/fsmonitor/fsm-path-utils-win32.c | 17 +++++ fsmonitor--daemon.h | 3 + fsmonitor-path-utils.h | 36 +++++++++- 6 files changed, 167 insertions(+), 3 deletions(-) diff --git a/builtin/fsmonitor--daemon.c b/builtin/fsmonitor--daemon.c index 0123fc33ed2..7a4cb78c7dd 100644 --- a/builtin/fsmonitor--daemon.c +++ b/builtin/fsmonitor--daemon.c @@ -3,6 +3,7 @@ #include "parse-options.h" #include "fsmonitor.h" #include "fsmonitor-ipc.h" +#include "fsmonitor-path-utils.h" #include "compat/fsmonitor/fsm-health.h" #include "compat/fsmonitor/fsm-listen.h" #include "fsmonitor--daemon.h" @@ -1282,6 +1283,11 @@ static int fsmonitor_run_daemon(void) strbuf_addstr(&state.path_worktree_watch, absolute_path(get_git_work_tree())); state.nr_paths_watching = 1; + strbuf_init(&state.alias.alias, 0); + strbuf_init(&state.alias.points_to, 0); + if ((err = fsmonitor__get_alias(state.path_worktree_watch.buf, &state.alias))) + goto done; + /* * We create and delete cookie files somewhere inside the .git * directory to help us keep sync with the file system. If @@ -1391,6 +1397,8 @@ done: strbuf_release(&state.path_gitdir_watch); strbuf_release(&state.path_cookie_prefix); strbuf_release(&state.path_ipc); + strbuf_release(&state.alias.alias); + strbuf_release(&state.alias.points_to); return err; } diff --git a/compat/fsmonitor/fsm-listen-darwin.c b/compat/fsmonitor/fsm-listen-darwin.c index 8e208e8289e..daeee4e465c 100644 --- a/compat/fsmonitor/fsm-listen-darwin.c +++ b/compat/fsmonitor/fsm-listen-darwin.c @@ -26,6 +26,7 @@ #include "fsmonitor.h" #include "fsm-listen.h" #include "fsmonitor--daemon.h" +#include "fsmonitor-path-utils.h" struct fsm_listen_data { @@ -198,8 +199,9 @@ static void fsevent_callback(ConstFSEventStreamRef streamRef, struct string_list cookie_list = STRING_LIST_INIT_DUP; const char *path_k; const char *slash; - int k; + char *resolved = NULL; struct strbuf tmp = STRBUF_INIT; + int k; /* * Build a list of all filesystem changes into a private/local @@ -209,7 +211,12 @@ static void fsevent_callback(ConstFSEventStreamRef streamRef, /* * On Mac, we receive an array of absolute paths. */ - path_k = paths[k]; + free(resolved); + resolved = fsmonitor__resolve_alias(paths[k], &state->alias); + if (resolved) + path_k = resolved; + else + path_k = paths[k]; /* * If you want to debug FSEvents, log them to GIT_TRACE_FSMONITOR. @@ -238,6 +245,7 @@ static void fsevent_callback(ConstFSEventStreamRef streamRef, fsmonitor_force_resync(state); fsmonitor_batch__free_list(batch); string_list_clear(&cookie_list, 0); + batch = NULL; /* * We assume that any events that we received @@ -360,12 +368,14 @@ static void fsevent_callback(ConstFSEventStreamRef streamRef, } } + free(resolved); fsmonitor_publish(state, batch, &cookie_list); string_list_clear(&cookie_list, 0); strbuf_release(&tmp); return; force_shutdown: + free(resolved); fsmonitor_batch__free_list(batch); string_list_clear(&cookie_list, 0); diff --git a/compat/fsmonitor/fsm-path-utils-darwin.c b/compat/fsmonitor/fsm-path-utils-darwin.c index 067cbe6990a..fc12fd831ec 100644 --- a/compat/fsmonitor/fsm-path-utils-darwin.c +++ b/compat/fsmonitor/fsm-path-utils-darwin.c @@ -1,5 +1,8 @@ #include "fsmonitor.h" #include "fsmonitor-path-utils.h" +#include +#include +#include #include #include @@ -38,3 +41,92 @@ int fsmonitor__is_fs_remote(const char *path) return -1; return fs.is_remote; } + +/* + * Scan the root directory for synthetic firmlinks that when resolved + * are a prefix of the path, stopping at the first one found. + * + * Some information about firmlinks and synthetic firmlinks: + * https://eclecticlight.co/2020/01/23/catalina-boot-volumes/ + * + * macOS no longer allows symlinks in the root directory; any link found + * there is therefore a synthetic firmlink. + * + * If this function gets called often, will want to cache all the firmlink + * information, but for now there is only one caller of this function. + * + * If there is more than one alias for the path, that is another + * matter altogether. + */ +int fsmonitor__get_alias(const char *path, struct alias_info *info) +{ + DIR *dir; + int retval = -1; + const char *const root = "/"; + struct stat st; + struct dirent *de; + struct strbuf alias; + struct strbuf points_to = STRBUF_INIT; + + dir = opendir(root); + if (!dir) + return error_errno(_("opendir('%s') failed"), root); + + strbuf_init(&alias, 256); + + while ((de = readdir(dir)) != NULL) { + strbuf_reset(&alias); + strbuf_addf(&alias, "%s%s", root, de->d_name); + + if (lstat(alias.buf, &st) < 0) { + error_errno(_("lstat('%s') failed"), alias.buf); + goto done; + } + + if (!S_ISLNK(st.st_mode)) + continue; + + if (strbuf_readlink(&points_to, alias.buf, st.st_size) < 0) { + error_errno(_("strbuf_readlink('%s') failed"), alias.buf); + goto done; + } + + if (!strncmp(points_to.buf, path, points_to.len) && + (path[points_to.len] == '/')) { + strbuf_addbuf(&info->alias, &alias); + strbuf_addbuf(&info->points_to, &points_to); + trace_printf_key(&trace_fsmonitor, + "Found alias for '%s' : '%s' -> '%s'", + path, info->alias.buf, info->points_to.buf); + retval = 0; + goto done; + } + } + retval = 0; /* no alias */ + +done: + strbuf_release(&alias); + strbuf_release(&points_to); + if (closedir(dir) < 0) + return error_errno(_("closedir('%s') failed"), root); + return retval; +} + +char *fsmonitor__resolve_alias(const char *path, + const struct alias_info *info) +{ + if (!info->alias.len) + return NULL; + + if ((!strncmp(info->alias.buf, path, info->alias.len)) + && path[info->alias.len] == '/') { + struct strbuf tmp = STRBUF_INIT; + const char *remainder = path + info->alias.len; + + strbuf_addbuf(&tmp, &info->points_to); + strbuf_add(&tmp, remainder, strlen(remainder)); + return strbuf_detach(&tmp, NULL); + } + + return NULL; +} diff --git a/compat/fsmonitor/fsm-path-utils-win32.c b/compat/fsmonitor/fsm-path-utils-win32.c index a90b8f7925b..0d95bbb416f 100644 --- a/compat/fsmonitor/fsm-path-utils-win32.c +++ b/compat/fsmonitor/fsm-path-utils-win32.c @@ -126,3 +126,20 @@ int fsmonitor__is_fs_remote(const char *path) return -1; return fs.is_remote; } + +/* + * No-op for now. + */ +int fsmonitor__get_alias(const char *path, struct alias_info *info) +{ + return 0; +} + +/* + * No-op for now. + */ +char *fsmonitor__resolve_alias(const char *path, + const struct alias_info *info) +{ + return NULL; +} diff --git a/fsmonitor--daemon.h b/fsmonitor--daemon.h index 2102a5c9ff5..e24838f9a86 100644 --- a/fsmonitor--daemon.h +++ b/fsmonitor--daemon.h @@ -8,6 +8,7 @@ #include "run-command.h" #include "simple-ipc.h" #include "thread-utils.h" +#include "fsmonitor-path-utils.h" struct fsmonitor_batch; struct fsmonitor_token_data; @@ -43,6 +44,7 @@ struct fsmonitor_daemon_state { struct strbuf path_worktree_watch; struct strbuf path_gitdir_watch; + struct alias_info alias; int nr_paths_watching; struct fsmonitor_token_data *current_token_data; @@ -59,6 +61,7 @@ struct fsmonitor_daemon_state { struct ipc_server_data *ipc_server_data; struct strbuf path_ipc; + }; /* diff --git a/fsmonitor-path-utils.h b/fsmonitor-path-utils.h index e48592887e7..2624798d2c7 100644 --- a/fsmonitor-path-utils.h +++ b/fsmonitor-path-utils.h @@ -1,13 +1,21 @@ #ifndef FSM_PATH_UTILS_H #define FSM_PATH_UTILS_H +#include "strbuf.h" + +struct alias_info +{ + struct strbuf alias; + struct strbuf points_to; +}; + struct fs_info { int is_remote; char *typename; }; /* - * Get some basic filesystem informtion for the given path + * Get some basic filesystem information for the given path * * Returns -1 on error, zero otherwise. */ @@ -20,4 +28,30 @@ int fsmonitor__get_fs_info(const char *path, struct fs_info *fs_info); */ int fsmonitor__is_fs_remote(const char *path); +/* + * Get the alias in given path, if any. + * + * Sets alias to the first alias that matches any part of the path. + * + * If an alias is found, info.alias and info.points_to are set to the + * found mapping. + * + * Returns -1 on error, 0 otherwise. + * + * The caller owns the storage that is occupied by info.alias and + * info.points_to and is responsible for releasing it. + */ +int fsmonitor__get_alias(const char *path, struct alias_info *info); + +/* + * Resolve the path against the given alias. + * + * Returns the resolved path if there is one, NULL otherwise. + * + * The caller owns the storage that the returned string occupies and + * is responsible for releasing it. + */ +char *fsmonitor__resolve_alias(const char *path, + const struct alias_info *info); + #endif