Merge branch 'ed/fsmonitor-on-networked-macos'

By default, use of fsmonitor on a repository on networked
filesystem is disabled. Add knobs to make it workable on macOS.

* ed/fsmonitor-on-networked-macos:
  fsmonitor: fix leak of warning message
  fsmonitor: add documentation for allowRemote and socketDir options
  fsmonitor: check for compatability before communicating with fsmonitor
  fsmonitor: deal with synthetic firmlinks on macOS
  fsmonitor: avoid socket location check if using hook
  fsmonitor: relocate socket file if .git directory is remote
  fsmonitor: refactor filesystem checks to common interface
This commit is contained in:
Junio C Hamano
2022-10-17 14:56:31 -07:00
20 changed files with 590 additions and 249 deletions

View File

@@ -0,0 +1,52 @@
#include "cache.h"
#include "config.h"
#include "strbuf.h"
#include "fsmonitor.h"
#include "fsmonitor-ipc.h"
#include "fsmonitor-path-utils.h"
static GIT_PATH_FUNC(fsmonitor_ipc__get_default_path, "fsmonitor--daemon.ipc")
const char *fsmonitor_ipc__get_path(struct repository *r)
{
static const char *ipc_path = NULL;
SHA_CTX sha1ctx;
char *sock_dir = NULL;
struct strbuf ipc_file = STRBUF_INIT;
unsigned char hash[SHA_DIGEST_LENGTH];
if (!r)
BUG("No repository passed into fsmonitor_ipc__get_path");
if (ipc_path)
return ipc_path;
/* By default the socket file is created in the .git directory */
if (fsmonitor__is_fs_remote(r->gitdir) < 1) {
ipc_path = fsmonitor_ipc__get_default_path();
return ipc_path;
}
SHA1_Init(&sha1ctx);
SHA1_Update(&sha1ctx, r->worktree, strlen(r->worktree));
SHA1_Final(hash, &sha1ctx);
repo_config_get_string(r, "fsmonitor.socketdir", &sock_dir);
/* Create the socket file in either socketDir or $HOME */
if (sock_dir && *sock_dir) {
strbuf_addf(&ipc_file, "%s/.git-fsmonitor-%s",
sock_dir, hash_to_hex(hash));
} else {
strbuf_addf(&ipc_file, "~/.git-fsmonitor-%s", hash_to_hex(hash));
}
free(sock_dir);
ipc_path = interpolate_path(ipc_file.buf, 1);
if (!ipc_path)
die(_("Invalid path: %s"), ipc_file.buf);
strbuf_release(&ipc_file);
return ipc_path;
}

View File

@@ -0,0 +1,9 @@
#include "config.h"
#include "fsmonitor-ipc.h"
const char *fsmonitor_ipc__get_path(struct repository *r) {
static char *ret;
if (!ret)
ret = git_pathdup("fsmonitor--daemon.ipc");
return ret;
}

View File

@@ -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);

View File

@@ -0,0 +1,135 @@
#include "fsmonitor.h"
#include "fsmonitor-path-utils.h"
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/param.h>
#include <sys/mount.h>
int fsmonitor__get_fs_info(const char *path, struct fs_info *fs_info)
{
struct statfs fs;
if (statfs(path, &fs) == -1) {
int saved_errno = errno;
trace_printf_key(&trace_fsmonitor, "statfs('%s') failed: %s",
path, strerror(saved_errno));
errno = saved_errno;
return -1;
}
trace_printf_key(&trace_fsmonitor,
"statfs('%s') [type 0x%08x][flags 0x%08x] '%s'",
path, fs.f_type, fs.f_flags, fs.f_fstypename);
if (!(fs.f_flags & MNT_LOCAL))
fs_info->is_remote = 1;
else
fs_info->is_remote = 0;
fs_info->typename = xstrdup(fs.f_fstypename);
trace_printf_key(&trace_fsmonitor,
"'%s' is_remote: %d",
path, fs_info->is_remote);
return 0;
}
int fsmonitor__is_fs_remote(const char *path)
{
struct fs_info fs;
if (fsmonitor__get_fs_info(path, &fs))
return -1;
free(fs.typename);
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;
}

View File

@@ -0,0 +1,145 @@
#include "cache.h"
#include "fsmonitor.h"
#include "fsmonitor-path-utils.h"
/*
* Check remote working directory protocol.
*
* Return -1 if client machine cannot get remote protocol information.
*/
static int check_remote_protocol(wchar_t *wpath)
{
HANDLE h;
FILE_REMOTE_PROTOCOL_INFO proto_info;
h = CreateFileW(wpath, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS, NULL);
if (h == INVALID_HANDLE_VALUE) {
error(_("[GLE %ld] unable to open for read '%ls'"),
GetLastError(), wpath);
return -1;
}
if (!GetFileInformationByHandleEx(h, FileRemoteProtocolInfo,
&proto_info, sizeof(proto_info))) {
error(_("[GLE %ld] unable to get protocol information for '%ls'"),
GetLastError(), wpath);
CloseHandle(h);
return -1;
}
CloseHandle(h);
trace_printf_key(&trace_fsmonitor,
"check_remote_protocol('%ls') remote protocol %#8.8lx",
wpath, proto_info.Protocol);
return 0;
}
/*
* Notes for testing:
*
* (a) Windows allows a network share to be mapped to a drive letter.
* (This is the normal method to access it.)
*
* $ NET USE Z: \\server\share
* $ git -C Z:/repo status
*
* (b) Windows allows a network share to be referenced WITHOUT mapping
* it to drive letter.
*
* $ NET USE \\server\share\dir
* $ git -C //server/share/repo status
*
* (c) Windows allows "SUBST" to create a fake drive mapping to an
* arbitrary path (which may be remote)
*
* $ SUBST Q: Z:\repo
* $ git -C Q:/ status
*
* (d) Windows allows a directory symlink to be created on a local
* file system that points to a remote repo.
*
* $ mklink /d ./link //server/share/repo
* $ git -C ./link status
*/
int fsmonitor__get_fs_info(const char *path, struct fs_info *fs_info)
{
wchar_t wpath[MAX_PATH];
wchar_t wfullpath[MAX_PATH];
size_t wlen;
UINT driveType;
/*
* Do everything in wide chars because the drive letter might be
* a multi-byte sequence. See win32_has_dos_drive_prefix().
*/
if (xutftowcs_path(wpath, path) < 0) {
return -1;
}
/*
* GetDriveTypeW() requires a final slash. We assume that the
* worktree pathname points to an actual directory.
*/
wlen = wcslen(wpath);
if (wpath[wlen - 1] != L'\\' && wpath[wlen - 1] != L'/') {
wpath[wlen++] = L'\\';
wpath[wlen] = 0;
}
/*
* Normalize the path. If nothing else, this converts forward
* slashes to backslashes. This is essential to get GetDriveTypeW()
* correctly handle some UNC "\\server\share\..." paths.
*/
if (!GetFullPathNameW(wpath, MAX_PATH, wfullpath, NULL)) {
return -1;
}
driveType = GetDriveTypeW(wfullpath);
trace_printf_key(&trace_fsmonitor,
"DriveType '%s' L'%ls' (%u)",
path, wfullpath, driveType);
if (driveType == DRIVE_REMOTE) {
fs_info->is_remote = 1;
if (check_remote_protocol(wfullpath) < 0)
return -1;
} else {
fs_info->is_remote = 0;
}
trace_printf_key(&trace_fsmonitor,
"'%s' is_remote: %d",
path, fs_info->is_remote);
return 0;
}
int fsmonitor__is_fs_remote(const char *path)
{
struct fs_info fs;
if (fsmonitor__get_fs_info(path, &fs))
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;
}

View File

@@ -1,32 +1,10 @@
#include "cache.h"
#include "config.h"
#include "repository.h"
#include "fsmonitor-settings.h"
#include "fsmonitor.h"
#include <sys/param.h>
#include <sys/mount.h>
#include "fsmonitor-ipc.h"
#include "fsmonitor-settings.h"
#include "fsmonitor-path-utils.h"
/*
* [1] Remote working directories are problematic for FSMonitor.
*
* The underlying file system on the server machine and/or the remote
* mount type (NFS, SAMBA, etc.) dictates whether notification events
* are available at all to remote client machines.
*
* Kernel differences between the server and client machines also
* dictate the how (buffering, frequency, de-dup) the events are
* delivered to client machine processes.
*
* A client machine (such as a laptop) may choose to suspend/resume
* and it is unclear (without lots of testing) whether the watcher can
* resync after a resume. We might be able to treat this as a normal
* "events were dropped by the kernel" event and do our normal "flush
* and resync" --or-- we might need to close the existing (zombie?)
* notification fd and create a new one.
*
* In theory, the above issues need to be addressed whether we are
* using the Hook or IPC API.
*
/*
* For the builtin FSMonitor, we create the Unix domain socket for the
* IPC in the .git directory. If the working directory is remote,
* then the socket will be created on the remote file system. This
@@ -38,52 +16,47 @@
* be taken to ensure that $HOME is actually local and not a managed
* file share.)
*
* So (for now at least), mark remote working directories as
* incompatible.
*
*
* [2] FAT32 and NTFS working directories are problematic too.
* FAT32 and NTFS working directories are problematic too.
*
* The builtin FSMonitor uses a Unix domain socket in the .git
* directory for IPC. These Windows drive formats do not support
* Unix domain sockets, so mark them as incompatible for the daemon.
*
*/
static enum fsmonitor_reason check_volume(struct repository *r)
static enum fsmonitor_reason check_uds_volume(struct repository *r)
{
struct statfs fs;
struct fs_info fs;
const char *ipc_path = fsmonitor_ipc__get_path(r);
struct strbuf path = STRBUF_INIT;
strbuf_add(&path, ipc_path, strlen(ipc_path));
if (statfs(r->worktree, &fs) == -1) {
int saved_errno = errno;
trace_printf_key(&trace_fsmonitor, "statfs('%s') failed: %s",
r->worktree, strerror(saved_errno));
errno = saved_errno;
if (fsmonitor__get_fs_info(dirname(path.buf), &fs) == -1) {
strbuf_release(&path);
return FSMONITOR_REASON_ERROR;
}
trace_printf_key(&trace_fsmonitor,
"statfs('%s') [type 0x%08x][flags 0x%08x] '%s'",
r->worktree, fs.f_type, fs.f_flags, fs.f_fstypename);
strbuf_release(&path);
if (!(fs.f_flags & MNT_LOCAL))
return FSMONITOR_REASON_REMOTE;
if (!strcmp(fs.f_fstypename, "msdos")) /* aka FAT32 */
return FSMONITOR_REASON_NOSOCKETS;
if (!strcmp(fs.f_fstypename, "ntfs"))
if (fs.is_remote ||
!strcmp(fs.typename, "msdos") ||
!strcmp(fs.typename, "ntfs")) {
free(fs.typename);
return FSMONITOR_REASON_NOSOCKETS;
}
free(fs.typename);
return FSMONITOR_REASON_OK;
}
enum fsmonitor_reason fsm_os__incompatible(struct repository *r)
enum fsmonitor_reason fsm_os__incompatible(struct repository *r, int ipc)
{
enum fsmonitor_reason reason;
reason = check_volume(r);
if (reason != FSMONITOR_REASON_OK)
return reason;
if (ipc) {
reason = check_uds_volume(r);
if (reason != FSMONITOR_REASON_OK)
return reason;
}
return FSMONITOR_REASON_OK;
}

View File

@@ -1,8 +1,9 @@
#include "cache.h"
#include "config.h"
#include "repository.h"
#include "fsmonitor-settings.h"
#include "fsmonitor.h"
#include "fsmonitor-settings.h"
#include "fsmonitor-path-utils.h"
/*
* VFS for Git is incompatible with FSMonitor.
@@ -24,172 +25,7 @@ static enum fsmonitor_reason check_vfs4git(struct repository *r)
return FSMONITOR_REASON_OK;
}
/*
* Check if monitoring remote working directories is allowed.
*
* By default, monitoring remote working directories is
* disabled. Users may override this behavior in enviroments where
* they have proper support.
*/
static int check_config_allowremote(struct repository *r)
{
int allow;
if (!repo_config_get_bool(r, "fsmonitor.allowremote", &allow))
return allow;
return -1; /* fsmonitor.allowremote not set */
}
/*
* Check remote working directory protocol.
*
* Error if client machine cannot get remote protocol information.
*/
static int check_remote_protocol(wchar_t *wpath)
{
HANDLE h;
FILE_REMOTE_PROTOCOL_INFO proto_info;
h = CreateFileW(wpath, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS, NULL);
if (h == INVALID_HANDLE_VALUE) {
error(_("[GLE %ld] unable to open for read '%ls'"),
GetLastError(), wpath);
return -1;
}
if (!GetFileInformationByHandleEx(h, FileRemoteProtocolInfo,
&proto_info, sizeof(proto_info))) {
error(_("[GLE %ld] unable to get protocol information for '%ls'"),
GetLastError(), wpath);
CloseHandle(h);
return -1;
}
CloseHandle(h);
trace_printf_key(&trace_fsmonitor,
"check_remote_protocol('%ls') remote protocol %#8.8lx",
wpath, proto_info.Protocol);
return 0;
}
/*
* Remote working directories are problematic for FSMonitor.
*
* The underlying file system on the server machine and/or the remote
* mount type dictates whether notification events are available at
* all to remote client machines.
*
* Kernel differences between the server and client machines also
* dictate the how (buffering, frequency, de-dup) the events are
* delivered to client machine processes.
*
* A client machine (such as a laptop) may choose to suspend/resume
* and it is unclear (without lots of testing) whether the watcher can
* resync after a resume. We might be able to treat this as a normal
* "events were dropped by the kernel" event and do our normal "flush
* and resync" --or-- we might need to close the existing (zombie?)
* notification fd and create a new one.
*
* In theory, the above issues need to be addressed whether we are
* using the Hook or IPC API.
*
* So (for now at least), mark remote working directories as
* incompatible.
*
* Notes for testing:
*
* (a) Windows allows a network share to be mapped to a drive letter.
* (This is the normal method to access it.)
*
* $ NET USE Z: \\server\share
* $ git -C Z:/repo status
*
* (b) Windows allows a network share to be referenced WITHOUT mapping
* it to drive letter.
*
* $ NET USE \\server\share\dir
* $ git -C //server/share/repo status
*
* (c) Windows allows "SUBST" to create a fake drive mapping to an
* arbitrary path (which may be remote)
*
* $ SUBST Q: Z:\repo
* $ git -C Q:/ status
*
* (d) Windows allows a directory symlink to be created on a local
* file system that points to a remote repo.
*
* $ mklink /d ./link //server/share/repo
* $ git -C ./link status
*/
static enum fsmonitor_reason check_remote(struct repository *r)
{
int ret;
wchar_t wpath[MAX_PATH];
wchar_t wfullpath[MAX_PATH];
size_t wlen;
UINT driveType;
/*
* Do everything in wide chars because the drive letter might be
* a multi-byte sequence. See win32_has_dos_drive_prefix().
*/
if (xutftowcs_path(wpath, r->worktree) < 0)
return FSMONITOR_REASON_ERROR;
/*
* GetDriveTypeW() requires a final slash. We assume that the
* worktree pathname points to an actual directory.
*/
wlen = wcslen(wpath);
if (wpath[wlen - 1] != L'\\' && wpath[wlen - 1] != L'/') {
wpath[wlen++] = L'\\';
wpath[wlen] = 0;
}
/*
* Normalize the path. If nothing else, this converts forward
* slashes to backslashes. This is essential to get GetDriveTypeW()
* correctly handle some UNC "\\server\share\..." paths.
*/
if (!GetFullPathNameW(wpath, MAX_PATH, wfullpath, NULL))
return FSMONITOR_REASON_ERROR;
driveType = GetDriveTypeW(wfullpath);
trace_printf_key(&trace_fsmonitor,
"DriveType '%s' L'%ls' (%u)",
r->worktree, wfullpath, driveType);
if (driveType == DRIVE_REMOTE) {
trace_printf_key(&trace_fsmonitor,
"check_remote('%s') true",
r->worktree);
ret = check_remote_protocol(wfullpath);
if (ret < 0)
return FSMONITOR_REASON_ERROR;
switch (check_config_allowremote(r)) {
case 0: /* config overrides and disables */
return FSMONITOR_REASON_REMOTE;
case 1: /* config overrides and enables */
return FSMONITOR_REASON_OK;
default:
break; /* config has no opinion */
}
return FSMONITOR_REASON_REMOTE;
}
return FSMONITOR_REASON_OK;
}
enum fsmonitor_reason fsm_os__incompatible(struct repository *r)
enum fsmonitor_reason fsm_os__incompatible(struct repository *r, int ipc)
{
enum fsmonitor_reason reason;
@@ -197,9 +33,5 @@ enum fsmonitor_reason fsm_os__incompatible(struct repository *r)
if (reason != FSMONITOR_REASON_OK)
return reason;
reason = check_remote(r);
if (reason != FSMONITOR_REASON_OK)
return reason;
return FSMONITOR_REASON_OK;
}