Subject: [PATCH v7 0/6] fsmonitor: option to allow fsmonitor to run against network-mounted repos

From: "Eric DeCosta via GitGitGadget" <[email-masked]>
Date: Fri, 16 Sep 2022 19:53:28 +0000

Follow-on to the work done to allow Windows to work against network-mounted
repos for macOS.

Have macOS take advantage of the same configuration option,
'fsmonitor.allowRemote' that was introduced for Windows. Setting this option
to true will override the default behavior (erroring-out) when a
network-mounted repo is detected by fsmonitor.

The added wrinkle being that the Unix domain socket (UDS) file used for IPC
cannot be created in a network location; instead $HOME is used if the
default location is on the network. The user may, optionally, set the
'fsmonitor.socketDir' configuration option to a valid, local directory if
$HOME itself is on the network or is simply not the desired location for the
UDS file.

An additional issue is that for mount points in the root directory, FSEvents
does not report a path that matches the worktree directory due to the
introduction of 'synthetic firmlinks'. fsmonitor must map the FSEvents paths
to the worktree directory by interrogating the root filesystem for synthetic
firmlinks and using that information to translate the path.

v7 differs from v6:

 * incorporates code review feedback

v6 differs from v5:

 * incorporates earlier, Windows-specific changes that have not made it back
   yet to the master branch
 * incorporates code review feedback
 * adds documentation for 'fsmonitor.allowRemote' and 'fsmonitor.socketDir'

v5 differs significantly from earlier versions:

 * redesign of handling 'fsmonitor.allowRemote' and 'fsmonitor.socketDir'
   such that these options are no longer added to the settings data
   structure but are rather read from config at point of use
 * refactoring of code for handling platform-specific file system checks via
   a common interface to avoid platform #ifdef in IPC code and be in-model
   with other platform-specific fsmonitor code
 * dealing with 'synthetic firmlinks' on macOS

Eric DeCosta (6):
  fsmonitor: refactor filesystem checks to common interface
  fsmonitor: relocate socket file if .git directory is remote
  fsmonitor: avoid socket location check if using hook
  fsmonitor: deal with synthetic firmlinks on macOS
  fsmonitor: deal with synthetic firmlinks on macOS
  fsmonitor: add documentation for allowRemote and socketDir options

 Documentation/git-fsmonitor--daemon.txt  |  35 +++++
 Makefile                                 |   2 +
 builtin/fsmonitor--daemon.c              |  11 +-
 compat/fsmonitor/fsm-ipc-darwin.c        |  49 +++++++
 compat/fsmonitor/fsm-ipc-win32.c         |   9 ++
 compat/fsmonitor/fsm-listen-darwin.c     |   6 +-
 compat/fsmonitor/fsm-path-utils-darwin.c | 132 +++++++++++++++++
 compat/fsmonitor/fsm-path-utils-win32.c  | 145 +++++++++++++++++++
 compat/fsmonitor/fsm-settings-darwin.c   |  70 +++------
 compat/fsmonitor/fsm-settings-win32.c    | 174 +----------------------
 contrib/buildsystems/CMakeLists.txt      |   4 +
 fsmonitor--daemon.h                      |   6 +
 fsmonitor-ipc.c                          |  18 ++-
 fsmonitor-ipc.h                          |   4 +-
 fsmonitor-path-utils.h                   |  59 ++++++++
 fsmonitor-settings.c                     |  58 +++++++-
 fsmonitor-settings.h                     |   2 +-
 17 files changed, 547 insertions(+), 237 deletions(-)
 create mode 100644 compat/fsmonitor/fsm-ipc-darwin.c
 create mode 100644 compat/fsmonitor/fsm-ipc-win32.c
 create mode 100644 compat/fsmonitor/fsm-path-utils-darwin.c
 create mode 100644 compat/fsmonitor/fsm-path-utils-win32.c
 create mode 100644 fsmonitor-path-utils.h

base-commit: d3fa443f97e3a8d75b51341e2d5bac380b7422df
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1326%2Fedecosta-mw%2Ffsmonitor_macos-v7
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1326/edecosta-mw/fsmonitor_macos-v7
Pull-Request: https://github.com/gitgitgadget/git/pull/1326

Range-diff vs v6:

 1:  3233c908c4a < -:  ----------- fsmonitor: option to allow fsmonitor to run against network-mounted repos
 2:  d2a8fc6b707 = 1:  155a6890806 fsmonitor: refactor filesystem checks to common interface
 3:  edef029a298 ! 2:  075340bd2a7 fsmonitor: relocate socket file if .git directory is remote
     @@ Makefile: ifdef FSMONITOR_DAEMON_BACKEND
       
       ifdef FSMONITOR_OS_SETTINGS
      
     + ## builtin/fsmonitor--daemon.c ##
     +@@ builtin/fsmonitor--daemon.c: static int fsmonitor_run_daemon(void)
     + 	 * directory.)
     + 	 */
     + 	strbuf_init(&state.path_ipc, 0);
     +-	strbuf_addstr(&state.path_ipc, absolute_path(fsmonitor_ipc__get_path()));
     ++	strbuf_addstr(&state.path_ipc,
     ++		absolute_path(fsmonitor_ipc__get_path(the_repository)));
     + 
     + 	/*
     + 	 * Confirm that we can create platform-specific resources for the
     +
       ## compat/fsmonitor/fsm-ipc-darwin.c (new) ##
      @@
      +#include "cache.h"
     @@ compat/fsmonitor/fsm-ipc-darwin.c (new)
      +
      +static GIT_PATH_FUNC(fsmonitor_ipc__get_default_path, "fsmonitor--daemon.ipc")
      +
     -+const char *fsmonitor_ipc__get_path(void)
     ++const char *fsmonitor_ipc__get_path(struct repository *r)
      +{
      +	static const char *ipc_path;
      +	SHA_CTX sha1ctx;
     @@ compat/fsmonitor/fsm-ipc-darwin.c (new)
      +	if (ipc_path)
      +		return ipc_path;
      +
     ++	if (!r)
     ++		r = the_repository;
     ++
      +	ipc_path = fsmonitor_ipc__get_default_path();
      +
      +	/* By default the socket file is created in the .git directory */
     @@ compat/fsmonitor/fsm-ipc-darwin.c (new)
      +		return ipc_path;
      +
      +	SHA1_Init(&sha1ctx);
     -+	SHA1_Update(&sha1ctx, the_repository->worktree, strlen(the_repository->worktree));
     ++	SHA1_Update(&sha1ctx, r->worktree, strlen(r->worktree));
      +	SHA1_Final(hash, &sha1ctx);
      +
     -+	repo_config_get_string(the_repository, "fsmonitor.socketdir", &sock_dir);
     ++	repo_config_get_string(r, "fsmonitor.socketdir", &sock_dir);
      +
      +	/* Create the socket file in either socketDir or $HOME */
      +	if (sock_dir && *sock_dir)
     @@ compat/fsmonitor/fsm-ipc-darwin.c (new)
      
       ## compat/fsmonitor/fsm-ipc-win32.c (new) ##
      @@
     -+#include "cache.h"
     ++#include "config.h"
      +#include "fsmonitor-ipc.h"
      +
     -+GIT_PATH_FUNC(fsmonitor_ipc__get_path, "fsmonitor--daemon.ipc")
     ++const char *fsmonitor_ipc__get_path(struct repository *r) {
     ++	static char *ret;
     ++	if (!ret)
     ++		ret = git_pathdup("fsmonitor--daemon.ipc");
     ++	return ret;
     ++}
     + \ No newline at end of file
     +
     + ## compat/fsmonitor/fsm-settings-darwin.c ##
     +@@
     + static enum fsmonitor_reason check_uds_volume(struct repository *r)
     + {
     + 	struct fs_info fs;
     +-	const char *ipc_path = fsmonitor_ipc__get_path();
     ++	const char *ipc_path = fsmonitor_ipc__get_path(r);
     + 	struct strbuf path = STRBUF_INIT;
     + 	strbuf_add(&path, ipc_path, strlen(ipc_path));
     + 
      
       ## contrib/buildsystems/CMakeLists.txt ##
      @@ contrib/buildsystems/CMakeLists.txt: if(SUPPORTS_SIMPLE_IPC)
     @@ contrib/buildsystems/CMakeLists.txt: if(SUPPORTS_SIMPLE_IPC)
       		add_compile_definitions(HAVE_FSMONITOR_OS_SETTINGS)
      
       ## fsmonitor-ipc.c ##
     +@@ fsmonitor-ipc.c: int fsmonitor_ipc__is_supported(void)
     + 	return 0;
     + }
     + 
     +-const char *fsmonitor_ipc__get_path(void)
     ++const char *fsmonitor_ipc__get_path(struct repository *r)
     + {
     + 	return NULL;
     + }
      @@ fsmonitor-ipc.c: int fsmonitor_ipc__is_supported(void)
       	return 1;
       }
     @@ fsmonitor-ipc.c: int fsmonitor_ipc__is_supported(void)
      -
       enum ipc_active_state fsmonitor_ipc__get_state(void)
       {
     - 	return ipc_get_active_state(fsmonitor_ipc__get_path());
     +-	return ipc_get_active_state(fsmonitor_ipc__get_path());
     ++	return ipc_get_active_state(fsmonitor_ipc__get_path(the_repository));
     + }
     + 
     + static int spawn_daemon(void)
     +@@ fsmonitor-ipc.c: int fsmonitor_ipc__send_query(const char *since_token,
     + 	trace2_data_string("fsm_client", NULL, "query/command", tok);
     + 
     + try_again:
     +-	state = ipc_client_try_connect(fsmonitor_ipc__get_path(), &options,
     +-				       &connection);
     ++	state = ipc_client_try_connect(fsmonitor_ipc__get_path(the_repository),
     ++						&options, &connection);
     + 
     + 	switch (state) {
     + 	case IPC_STATE__LISTENING:
     +@@ fsmonitor-ipc.c: try_again:
     + 
     + 	case IPC_STATE__INVALID_PATH:
     + 		ret = error(_("fsmonitor_ipc__send_query: invalid path '%s'"),
     +-			    fsmonitor_ipc__get_path());
     ++			    fsmonitor_ipc__get_path(the_repository));
     + 		goto done;
     + 
     + 	case IPC_STATE__OTHER_ERROR:
     + 	default:
     + 		ret = error(_("fsmonitor_ipc__send_query: unspecified error on '%s'"),
     +-			    fsmonitor_ipc__get_path());
     ++			    fsmonitor_ipc__get_path(the_repository));
     + 		goto done;
     + 	}
     + 
     +@@ fsmonitor-ipc.c: int fsmonitor_ipc__send_command(const char *command,
     + 	options.wait_if_busy = 1;
     + 	options.wait_if_not_found = 0;
     + 
     +-	state = ipc_client_try_connect(fsmonitor_ipc__get_path(), &options,
     +-				       &connection);
     ++	state = ipc_client_try_connect(fsmonitor_ipc__get_path(the_repository),
     ++						&options, &connection);
     + 	if (state != IPC_STATE__LISTENING) {
     + 		die(_("fsmonitor--daemon is not running"));
     + 		return -1;
     +
     + ## fsmonitor-ipc.h ##
     +@@
     + 
     + #include "simple-ipc.h"
     + 
     ++struct repository;
     ++
     + /*
     +  * Returns true if built-in file system monitor daemon is defined
     +  * for this platform.
     +@@ fsmonitor-ipc.h: int fsmonitor_ipc__is_supported(void);
     +  *
     +  * Returns NULL if the daemon is not supported on this platform.
     +  */
     +-const char *fsmonitor_ipc__get_path(void);
     ++const char *fsmonitor_ipc__get_path(struct repository *r);
     + 
     + /*
     +  * Try to determine whether there is a `git-fsmonitor--daemon` process
 4:  3428bcf8763 = 3:  5518d2f3e03 fsmonitor: avoid socket location check if using hook
 5:  9c1f408ae6d ! 4:  3a9fe473cf4 fsmonitor: deal with synthetic firmlinks on macOS
     @@ fsmonitor--daemon.h: struct fsmonitor_daemon_state {
       };
       
       /*
     -@@ fsmonitor--daemon.h: void fsmonitor_publish(struct fsmonitor_daemon_state *state,
     -  */
     - void fsmonitor_force_resync(struct fsmonitor_daemon_state *state);
     - 
     -+char *fsmonitor_resolve_alias(const char *path,
     -+	struct alias_info *alias);
     -+
     - #endif /* HAVE_FSMONITOR_DAEMON_BACKEND */
     - #endif /* FSMONITOR_DAEMON_H */
      
       ## fsmonitor-path-utils.h ##
      @@
 -:  ----------- > 5:  4d00adb1deb fsmonitor: deal with synthetic firmlinks on macOS
 6:  d2c95e34d3a = 6:  260591f5820 fsmonitor: add documentation for allowRemote and socketDir options

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