git@vger.kernel.org list mirror (unofficial, one of many)
 help / color / mirror / code / Atom feed
2526ad9194f626dbead02f1d99dfccd0cd095510 blob 6587 bytes (raw)

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
 
#include "cache.h"
#include "config.h"
#include "fsmonitor.h"
#include "fsm-health.h"
#include "fsmonitor--daemon.h"

/*
 * Every minute wake up and test our health.
 */
#define WAIT_FREQ_MS (60 * 1000)

enum interval_fn_ctx { CTX_INIT = 0, CTX_TERM, CTX_TIMER };

typedef int (interval_fn)(struct fsmonitor_daemon_state *state,
			  enum interval_fn_ctx ctx);

static interval_fn has_worktree_moved;

static interval_fn *table[] = {
	has_worktree_moved,
	NULL, /* must be last */
};

/*
 * Call all of the functions in the table.
 * Shortcut and return first error.
 *
 * Return 0 if all succeeded.
 */
static int call_all(struct fsmonitor_daemon_state *state,
		    enum interval_fn_ctx ctx)
{
	int k;

	for (k = 0; table[k]; k++) {
		int r = table[k](state, ctx);
		if (r)
			return r;
	}

	return 0;
}

struct fsm_health_data
{
	HANDLE hEventShutdown;

	HANDLE hHandles[1]; /* the array does not own these handles */
#define HEALTH_SHUTDOWN 0
	int nr_handles; /* number of active event handles */

	struct wt_moved
	{
		wchar_t wpath[MAX_PATH + 1];
		BY_HANDLE_FILE_INFORMATION bhfi;
	} wt_moved;
};

int fsm_health__ctor(struct fsmonitor_daemon_state *state)
{
	struct fsm_health_data *data;

	CALLOC_ARRAY(data, 1);

	data->hEventShutdown = CreateEvent(NULL, TRUE, FALSE, NULL);

	data->hHandles[HEALTH_SHUTDOWN] = data->hEventShutdown;
	data->nr_handles++;

	state->health_data = data;
	return 0;
}

void fsm_health__dtor(struct fsmonitor_daemon_state *state)
{
	struct fsm_health_data *data;

	if (!state || !state->health_data)
		return;

	data = state->health_data;

	CloseHandle(data->hEventShutdown);

	FREE_AND_NULL(state->health_data);
}

static int lookup_bhfi(wchar_t *wpath,
		       BY_HANDLE_FILE_INFORMATION *bhfi)
{
	DWORD desired_access = FILE_LIST_DIRECTORY;
	DWORD share_mode =
		FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE;
	HANDLE hDir;

	hDir = CreateFileW(wpath, desired_access, share_mode, NULL,
			   OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
	if (hDir == INVALID_HANDLE_VALUE) {
		error(_("[GLE %ld] health thread could not open '%ls'"),
		      GetLastError(), wpath);
		return -1;
	}

	if (!GetFileInformationByHandle(hDir, bhfi)) {
		error(_("[GLE %ld] health thread getting BHFI for '%ls'"),
		      GetLastError(), wpath);
		CloseHandle(hDir);
		return -1;
	}

	CloseHandle(hDir);
	return 0;
}

static int bhfi_eq(const BY_HANDLE_FILE_INFORMATION *bhfi_1,
		   const BY_HANDLE_FILE_INFORMATION *bhfi_2)
{
	return (bhfi_1->dwVolumeSerialNumber == bhfi_2->dwVolumeSerialNumber &&
		bhfi_1->nFileIndexHigh == bhfi_2->nFileIndexHigh &&
		bhfi_1->nFileIndexLow == bhfi_2->nFileIndexLow);
}

/*
 * Shutdown if the original worktree root directory been deleted,
 * moved, or renamed?
 *
 * Since the main thread did a "chdir(getenv($HOME))" and our CWD
 * is not in the worktree root directory and because the listener
 * thread added FILE_SHARE_DELETE to the watch handle, it is possible
 * for the root directory to be moved or deleted while we are still
 * watching it.  We want to detect that here and force a shutdown.
 *
 * Granted, a delete MAY cause some operations to fail, such as
 * GetOverlappedResult(), but it is not guaranteed.  And because
 * ReadDirectoryChangesW() only reports on changes *WITHIN* the
 * directory, not changes *ON* the directory, our watch will not
 * receive a delete event for it.
 *
 * A move/rename of the worktree root will also not generate an event.
 * And since the listener thread already has an open handle, it may
 * continue to receive events for events within the directory.
 * However, the pathname of the named-pipe was constructed using the
 * original location of the worktree root.  (Remember named-pipes are
 * stored in the NPFS and not in the actual file system.)  Clients
 * trying to talk to the worktree after the move/rename will not
 * reach our daemon process, since we're still listening on the
 * pipe with original path.
 *
 * Furthermore, if the user does something like:
 *
 *   $ mv repo repo.old
 *   $ git init repo
 *
 * A new daemon cannot be started in the new instance of "repo"
 * because the named-pipe is still being used by the daemon on
 * the original instance.
 *
 * So, detect move/rename/delete and shutdown.  This should also
 * handle unsafe drive removal.
 *
 * We use the file system unique ID to distinguish the original
 * directory instance from a new instance and force a shutdown
 * if the unique ID changes.
 *
 * Since a worktree move/rename/delete/unmount doesn't happen
 * that often (and we can't get an immediate event anyway), we
 * use a timeout and periodically poll it.
 */
static int has_worktree_moved(struct fsmonitor_daemon_state *state,
			      enum interval_fn_ctx ctx)
{
	struct fsm_health_data *data = state->health_data;
	BY_HANDLE_FILE_INFORMATION bhfi;
	int r;

	switch (ctx) {
	case CTX_TERM:
		return 0;

	case CTX_INIT:
		if (xutftowcs_path(data->wt_moved.wpath,
				   state->path_worktree_watch.buf) < 0) {
			error(_("could not convert to wide characters: '%s'"),
			      state->path_worktree_watch.buf);
			return -1;
		}

		/*
		 * On the first call we lookup the unique sequence ID for
		 * the worktree root directory.
		 */
		return lookup_bhfi(data->wt_moved.wpath, &data->wt_moved.bhfi);

	case CTX_TIMER:
		r = lookup_bhfi(data->wt_moved.wpath, &bhfi);
		if (r)
			return r;
		if (!bhfi_eq(&data->wt_moved.bhfi, &bhfi)) {
			error(_("BHFI changed '%ls'"), data->wt_moved.wpath);
			return -1;
		}
		return 0;

	default:
		die("unhandled case in 'has_worktree_moved': %d",
		    (int)ctx);
	}

	return 0;
}

void fsm_health__loop(struct fsmonitor_daemon_state *state)
{
	struct fsm_health_data *data = state->health_data;
	int r;

	r = call_all(state, CTX_INIT);
	if (r < 0)
		goto force_error_stop;
	if (r > 0)
		goto force_shutdown;

	for (;;) {
		DWORD dwWait = WaitForMultipleObjects(data->nr_handles,
						      data->hHandles,
						      FALSE, WAIT_FREQ_MS);

		if (dwWait == WAIT_OBJECT_0 + HEALTH_SHUTDOWN)
			goto clean_shutdown;

		if (dwWait == WAIT_TIMEOUT) {
			r = call_all(state, CTX_TIMER);
			if (r < 0)
				goto force_error_stop;
			if (r > 0)
				goto force_shutdown;
			continue;
		}

		error(_("health thread wait failed [GLE %ld]"),
		      GetLastError());
		goto force_error_stop;
	}

force_error_stop:
	state->health_error_code = -1;
force_shutdown:
	ipc_server_stop_async(state->ipc_server_data);
clean_shutdown:
	call_all(state, CTX_TERM);
	return;
}

void fsm_health__stop_async(struct fsmonitor_daemon_state *state)
{
	SetEvent(state->health_data->hHandles[HEALTH_SHUTDOWN]);
}
debug log:

solving 2526ad9194f ...
found 2526ad9194f in https://public-inbox.org/git/023fcd6e2b1163ab3d23b0d5933c14586d814ce0.1644940774.git.gitgitgadget@gmail.com/
found 3c3453369cd in https://public-inbox.org/git/a398cdb8a04228ff94e2f5467c010f4917b27042.1644940774.git.gitgitgadget@gmail.com/
found 94b1d020f25 in https://80x24.org/mirrors/git.git
preparing index
index prepared:
100644 94b1d020f25ee2383e940248f57339a3d8d9ed0c	compat/fsmonitor/fsm-health-win32.c

applying [1/2] https://public-inbox.org/git/a398cdb8a04228ff94e2f5467c010f4917b27042.1644940774.git.gitgitgadget@gmail.com/
diff --git a/compat/fsmonitor/fsm-health-win32.c b/compat/fsmonitor/fsm-health-win32.c
index 94b1d020f25..3c3453369cd 100644


applying [2/2] https://public-inbox.org/git/023fcd6e2b1163ab3d23b0d5933c14586d814ce0.1644940774.git.gitgitgadget@gmail.com/
diff --git a/compat/fsmonitor/fsm-health-win32.c b/compat/fsmonitor/fsm-health-win32.c
index 3c3453369cd..2526ad9194f 100644

Checking patch compat/fsmonitor/fsm-health-win32.c...
Applied patch compat/fsmonitor/fsm-health-win32.c cleanly.
Checking patch compat/fsmonitor/fsm-health-win32.c...
Applied patch compat/fsmonitor/fsm-health-win32.c cleanly.

index at:
100644 2526ad9194f626dbead02f1d99dfccd0cd095510	compat/fsmonitor/fsm-health-win32.c

Code repositories for project(s) associated with this inbox:

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).