summaryrefslogtreecommitdiffstats
path: root/builtin/fsmonitor--daemon.c
diff options
context:
space:
mode:
Diffstat (limited to 'builtin/fsmonitor--daemon.c')
-rw-r--r--builtin/fsmonitor--daemon.c1597
1 files changed, 1597 insertions, 0 deletions
diff --git a/builtin/fsmonitor--daemon.c b/builtin/fsmonitor--daemon.c
new file mode 100644
index 0000000..5d01db5
--- /dev/null
+++ b/builtin/fsmonitor--daemon.c
@@ -0,0 +1,1597 @@
+#include "builtin.h"
+#include "abspath.h"
+#include "config.h"
+#include "environment.h"
+#include "gettext.h"
+#include "parse-options.h"
+#include "fsmonitor-ll.h"
+#include "fsmonitor-ipc.h"
+#include "fsmonitor-path-utils.h"
+#include "fsmonitor-settings.h"
+#include "compat/fsmonitor/fsm-health.h"
+#include "compat/fsmonitor/fsm-listen.h"
+#include "fsmonitor--daemon.h"
+#include "simple-ipc.h"
+#include "khash.h"
+#include "pkt-line.h"
+#include "trace.h"
+#include "trace2.h"
+
+static const char * const builtin_fsmonitor__daemon_usage[] = {
+ N_("git fsmonitor--daemon start [<options>]"),
+ N_("git fsmonitor--daemon run [<options>]"),
+ "git fsmonitor--daemon stop",
+ "git fsmonitor--daemon status",
+ NULL
+};
+
+#ifdef HAVE_FSMONITOR_DAEMON_BACKEND
+/*
+ * Global state loaded from config.
+ */
+#define FSMONITOR__IPC_THREADS "fsmonitor.ipcthreads"
+static int fsmonitor__ipc_threads = 8;
+
+#define FSMONITOR__START_TIMEOUT "fsmonitor.starttimeout"
+static int fsmonitor__start_timeout_sec = 60;
+
+#define FSMONITOR__ANNOUNCE_STARTUP "fsmonitor.announcestartup"
+static int fsmonitor__announce_startup = 0;
+
+static int fsmonitor_config(const char *var, const char *value,
+ const struct config_context *ctx, void *cb)
+{
+ if (!strcmp(var, FSMONITOR__IPC_THREADS)) {
+ int i = git_config_int(var, value, ctx->kvi);
+ if (i < 1)
+ return error(_("value of '%s' out of range: %d"),
+ FSMONITOR__IPC_THREADS, i);
+ fsmonitor__ipc_threads = i;
+ return 0;
+ }
+
+ if (!strcmp(var, FSMONITOR__START_TIMEOUT)) {
+ int i = git_config_int(var, value, ctx->kvi);
+ if (i < 0)
+ return error(_("value of '%s' out of range: %d"),
+ FSMONITOR__START_TIMEOUT, i);
+ fsmonitor__start_timeout_sec = i;
+ return 0;
+ }
+
+ if (!strcmp(var, FSMONITOR__ANNOUNCE_STARTUP)) {
+ int is_bool;
+ int i = git_config_bool_or_int(var, value, ctx->kvi, &is_bool);
+ if (i < 0)
+ return error(_("value of '%s' not bool or int: %d"),
+ var, i);
+ fsmonitor__announce_startup = i;
+ return 0;
+ }
+
+ return git_default_config(var, value, ctx, cb);
+}
+
+/*
+ * Acting as a CLIENT.
+ *
+ * Send a "quit" command to the `git-fsmonitor--daemon` (if running)
+ * and wait for it to shutdown.
+ */
+static int do_as_client__send_stop(void)
+{
+ struct strbuf answer = STRBUF_INIT;
+ int ret;
+
+ ret = fsmonitor_ipc__send_command("quit", &answer);
+
+ /* The quit command does not return any response data. */
+ strbuf_release(&answer);
+
+ if (ret)
+ return ret;
+
+ trace2_region_enter("fsm_client", "polling-for-daemon-exit", NULL);
+ while (fsmonitor_ipc__get_state() == IPC_STATE__LISTENING)
+ sleep_millisec(50);
+ trace2_region_leave("fsm_client", "polling-for-daemon-exit", NULL);
+
+ return 0;
+}
+
+static int do_as_client__status(void)
+{
+ enum ipc_active_state state = fsmonitor_ipc__get_state();
+
+ switch (state) {
+ case IPC_STATE__LISTENING:
+ printf(_("fsmonitor-daemon is watching '%s'\n"),
+ the_repository->worktree);
+ return 0;
+
+ default:
+ printf(_("fsmonitor-daemon is not watching '%s'\n"),
+ the_repository->worktree);
+ return 1;
+ }
+}
+
+enum fsmonitor_cookie_item_result {
+ FCIR_ERROR = -1, /* could not create cookie file ? */
+ FCIR_INIT,
+ FCIR_SEEN,
+ FCIR_ABORT,
+};
+
+struct fsmonitor_cookie_item {
+ struct hashmap_entry entry;
+ char *name;
+ enum fsmonitor_cookie_item_result result;
+};
+
+static int cookies_cmp(const void *data UNUSED,
+ const struct hashmap_entry *he1,
+ const struct hashmap_entry *he2, const void *keydata)
+{
+ const struct fsmonitor_cookie_item *a =
+ container_of(he1, const struct fsmonitor_cookie_item, entry);
+ const struct fsmonitor_cookie_item *b =
+ container_of(he2, const struct fsmonitor_cookie_item, entry);
+
+ return strcmp(a->name, keydata ? keydata : b->name);
+}
+
+static enum fsmonitor_cookie_item_result with_lock__wait_for_cookie(
+ struct fsmonitor_daemon_state *state)
+{
+ /* assert current thread holding state->main_lock */
+
+ int fd;
+ struct fsmonitor_cookie_item *cookie;
+ struct strbuf cookie_pathname = STRBUF_INIT;
+ struct strbuf cookie_filename = STRBUF_INIT;
+ enum fsmonitor_cookie_item_result result;
+ int my_cookie_seq;
+
+ CALLOC_ARRAY(cookie, 1);
+
+ my_cookie_seq = state->cookie_seq++;
+
+ strbuf_addf(&cookie_filename, "%i-%i", getpid(), my_cookie_seq);
+
+ strbuf_addbuf(&cookie_pathname, &state->path_cookie_prefix);
+ strbuf_addbuf(&cookie_pathname, &cookie_filename);
+
+ cookie->name = strbuf_detach(&cookie_filename, NULL);
+ cookie->result = FCIR_INIT;
+ hashmap_entry_init(&cookie->entry, strhash(cookie->name));
+
+ hashmap_add(&state->cookies, &cookie->entry);
+
+ trace_printf_key(&trace_fsmonitor, "cookie-wait: '%s' '%s'",
+ cookie->name, cookie_pathname.buf);
+
+ /*
+ * Create the cookie file on disk and then wait for a notification
+ * that the listener thread has seen it.
+ */
+ fd = open(cookie_pathname.buf, O_WRONLY | O_CREAT | O_EXCL, 0600);
+ if (fd < 0) {
+ error_errno(_("could not create fsmonitor cookie '%s'"),
+ cookie->name);
+
+ cookie->result = FCIR_ERROR;
+ goto done;
+ }
+
+ /*
+ * Technically, close() and unlink() can fail, but we don't
+ * care here. We only created the file to trigger a watch
+ * event from the FS to know that when we're up to date.
+ */
+ close(fd);
+ unlink(cookie_pathname.buf);
+
+ /*
+ * Technically, this is an infinite wait (well, unless another
+ * thread sends us an abort). I'd like to change this to
+ * use `pthread_cond_timedwait()` and return an error/timeout
+ * and let the caller do the trivial response thing, but we
+ * don't have that routine in our thread-utils.
+ *
+ * After extensive beta testing I'm not really worried about
+ * this. Also note that the above open() and unlink() calls
+ * will cause at least two FS events on that path, so the odds
+ * of getting stuck are pretty slim.
+ */
+ while (cookie->result == FCIR_INIT)
+ pthread_cond_wait(&state->cookies_cond,
+ &state->main_lock);
+
+done:
+ hashmap_remove(&state->cookies, &cookie->entry, NULL);
+
+ result = cookie->result;
+
+ free(cookie->name);
+ free(cookie);
+ strbuf_release(&cookie_pathname);
+
+ return result;
+}
+
+/*
+ * Mark these cookies as _SEEN and wake up the corresponding client threads.
+ */
+static void with_lock__mark_cookies_seen(struct fsmonitor_daemon_state *state,
+ const struct string_list *cookie_names)
+{
+ /* assert current thread holding state->main_lock */
+
+ int k;
+ int nr_seen = 0;
+
+ for (k = 0; k < cookie_names->nr; k++) {
+ struct fsmonitor_cookie_item key;
+ struct fsmonitor_cookie_item *cookie;
+
+ key.name = cookie_names->items[k].string;
+ hashmap_entry_init(&key.entry, strhash(key.name));
+
+ cookie = hashmap_get_entry(&state->cookies, &key, entry, NULL);
+ if (cookie) {
+ trace_printf_key(&trace_fsmonitor, "cookie-seen: '%s'",
+ cookie->name);
+ cookie->result = FCIR_SEEN;
+ nr_seen++;
+ }
+ }
+
+ if (nr_seen)
+ pthread_cond_broadcast(&state->cookies_cond);
+}
+
+/*
+ * Set _ABORT on all pending cookies and wake up all client threads.
+ */
+static void with_lock__abort_all_cookies(struct fsmonitor_daemon_state *state)
+{
+ /* assert current thread holding state->main_lock */
+
+ struct hashmap_iter iter;
+ struct fsmonitor_cookie_item *cookie;
+ int nr_aborted = 0;
+
+ hashmap_for_each_entry(&state->cookies, &iter, cookie, entry) {
+ trace_printf_key(&trace_fsmonitor, "cookie-abort: '%s'",
+ cookie->name);
+ cookie->result = FCIR_ABORT;
+ nr_aborted++;
+ }
+
+ if (nr_aborted)
+ pthread_cond_broadcast(&state->cookies_cond);
+}
+
+/*
+ * Requests to and from a FSMonitor Protocol V2 provider use an opaque
+ * "token" as a virtual timestamp. Clients can request a summary of all
+ * created/deleted/modified files relative to a token. In the response,
+ * clients receive a new token for the next (relative) request.
+ *
+ *
+ * Token Format
+ * ============
+ *
+ * The contents of the token are private and provider-specific.
+ *
+ * For the built-in fsmonitor--daemon, we define a token as follows:
+ *
+ * "builtin" ":" <token_id> ":" <sequence_nr>
+ *
+ * The "builtin" prefix is used as a namespace to avoid conflicts
+ * with other providers (such as Watchman).
+ *
+ * The <token_id> is an arbitrary OPAQUE string, such as a GUID,
+ * UUID, or {timestamp,pid}. It is used to group all filesystem
+ * events that happened while the daemon was monitoring (and in-sync
+ * with the filesystem).
+ *
+ * Unlike FSMonitor Protocol V1, it is not defined as a timestamp
+ * and does not define less-than/greater-than relationships.
+ * (There are too many race conditions to rely on file system
+ * event timestamps.)
+ *
+ * The <sequence_nr> is a simple integer incremented whenever the
+ * daemon needs to make its state public. For example, if 1000 file
+ * system events come in, but no clients have requested the data,
+ * the daemon can continue to accumulate file changes in the same
+ * bin and does not need to advance the sequence number. However,
+ * as soon as a client does arrive, the daemon needs to start a new
+ * bin and increment the sequence number.
+ *
+ * The sequence number serves as the boundary between 2 sets
+ * of bins -- the older ones that the client has already seen
+ * and the newer ones that it hasn't.
+ *
+ * When a new <token_id> is created, the <sequence_nr> is reset to
+ * zero.
+ *
+ *
+ * About Token Ids
+ * ===============
+ *
+ * A new token_id is created:
+ *
+ * [1] each time the daemon is started.
+ *
+ * [2] any time that the daemon must re-sync with the filesystem
+ * (such as when the kernel drops or we miss events on a very
+ * active volume).
+ *
+ * [3] in response to a client "flush" command (for dropped event
+ * testing).
+ *
+ * When a new token_id is created, the daemon is free to discard all
+ * cached filesystem events associated with any previous token_ids.
+ * Events associated with a non-current token_id will never be sent
+ * to a client. A token_id change implicitly means that the daemon
+ * has gap in its event history.
+ *
+ * Therefore, clients that present a token with a stale (non-current)
+ * token_id will always be given a trivial response.
+ */
+struct fsmonitor_token_data {
+ struct strbuf token_id;
+ struct fsmonitor_batch *batch_head;
+ struct fsmonitor_batch *batch_tail;
+ uint64_t client_ref_count;
+};
+
+struct fsmonitor_batch {
+ struct fsmonitor_batch *next;
+ uint64_t batch_seq_nr;
+ const char **interned_paths;
+ size_t nr, alloc;
+ time_t pinned_time;
+};
+
+static struct fsmonitor_token_data *fsmonitor_new_token_data(void)
+{
+ static int test_env_value = -1;
+ static uint64_t flush_count = 0;
+ struct fsmonitor_token_data *token;
+ struct fsmonitor_batch *batch;
+
+ CALLOC_ARRAY(token, 1);
+ batch = fsmonitor_batch__new();
+
+ strbuf_init(&token->token_id, 0);
+ token->batch_head = batch;
+ token->batch_tail = batch;
+ token->client_ref_count = 0;
+
+ if (test_env_value < 0)
+ test_env_value = git_env_bool("GIT_TEST_FSMONITOR_TOKEN", 0);
+
+ if (!test_env_value) {
+ struct timeval tv;
+ struct tm tm;
+ time_t secs;
+
+ gettimeofday(&tv, NULL);
+ secs = tv.tv_sec;
+ gmtime_r(&secs, &tm);
+
+ strbuf_addf(&token->token_id,
+ "%"PRIu64".%d.%4d%02d%02dT%02d%02d%02d.%06ldZ",
+ flush_count++,
+ getpid(),
+ tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+ tm.tm_hour, tm.tm_min, tm.tm_sec,
+ (long)tv.tv_usec);
+ } else {
+ strbuf_addf(&token->token_id, "test_%08x", test_env_value++);
+ }
+
+ /*
+ * We created a new <token_id> and are starting a new series
+ * of tokens with a zero <seq_nr>.
+ *
+ * Since clients cannot guess our new (non test) <token_id>
+ * they will always receive a trivial response (because of the
+ * mismatch on the <token_id>). The trivial response will
+ * tell them our new <token_id> so that subsequent requests
+ * will be relative to our new series. (And when sending that
+ * response, we pin the current head of the batch list.)
+ *
+ * Even if the client correctly guesses the <token_id>, their
+ * request of "builtin:<token_id>:0" asks for all changes MORE
+ * RECENT than batch/bin 0.
+ *
+ * This implies that it is a waste to accumulate paths in the
+ * initial batch/bin (because they will never be transmitted).
+ *
+ * So the daemon could be running for days and watching the
+ * file system, but doesn't need to actually accumulate any
+ * paths UNTIL we need to set a reference point for a later
+ * relative request.
+ *
+ * However, it is very useful for testing to always have a
+ * reference point set. Pin batch 0 to force early file system
+ * events to accumulate.
+ */
+ if (test_env_value)
+ batch->pinned_time = time(NULL);
+
+ return token;
+}
+
+struct fsmonitor_batch *fsmonitor_batch__new(void)
+{
+ struct fsmonitor_batch *batch;
+
+ CALLOC_ARRAY(batch, 1);
+
+ return batch;
+}
+
+void fsmonitor_batch__free_list(struct fsmonitor_batch *batch)
+{
+ while (batch) {
+ struct fsmonitor_batch *next = batch->next;
+
+ /*
+ * The actual strings within the array of this batch
+ * are interned, so we don't own them. We only own
+ * the array.
+ */
+ free(batch->interned_paths);
+ free(batch);
+
+ batch = next;
+ }
+}
+
+void fsmonitor_batch__add_path(struct fsmonitor_batch *batch,
+ const char *path)
+{
+ const char *interned_path = strintern(path);
+
+ trace_printf_key(&trace_fsmonitor, "event: %s", interned_path);
+
+ ALLOC_GROW(batch->interned_paths, batch->nr + 1, batch->alloc);
+ batch->interned_paths[batch->nr++] = interned_path;
+}
+
+static void fsmonitor_batch__combine(struct fsmonitor_batch *batch_dest,
+ const struct fsmonitor_batch *batch_src)
+{
+ size_t k;
+
+ ALLOC_GROW(batch_dest->interned_paths,
+ batch_dest->nr + batch_src->nr + 1,
+ batch_dest->alloc);
+
+ for (k = 0; k < batch_src->nr; k++)
+ batch_dest->interned_paths[batch_dest->nr++] =
+ batch_src->interned_paths[k];
+}
+
+/*
+ * To keep the batch list from growing unbounded in response to filesystem
+ * activity, we try to truncate old batches from the end of the list as
+ * they become irrelevant.
+ *
+ * We assume that the .git/index will be updated with the most recent token
+ * any time the index is updated. And future commands will only ask for
+ * recent changes *since* that new token. So as tokens advance into the
+ * future, older batch items will never be requested/needed. So we can
+ * truncate them without loss of functionality.
+ *
+ * However, multiple commands may be talking to the daemon concurrently
+ * or perform a slow command, so a little "token skew" is possible.
+ * Therefore, we want this to be a little bit lazy and have a generous
+ * delay.
+ *
+ * The current reader thread walked backwards in time from `token->batch_head`
+ * back to `batch_marker` somewhere in the middle of the batch list.
+ *
+ * Let's walk backwards in time from that marker an arbitrary delay
+ * and truncate the list there. Note that these timestamps are completely
+ * artificial (based on when we pinned the batch item) and not on any
+ * filesystem activity.
+ *
+ * Return the obsolete portion of the list after we have removed it from
+ * the official list so that the caller can free it after leaving the lock.
+ */
+#define MY_TIME_DELAY_SECONDS (5 * 60) /* seconds */
+
+static struct fsmonitor_batch *with_lock__truncate_old_batches(
+ struct fsmonitor_daemon_state *state,
+ const struct fsmonitor_batch *batch_marker)
+{
+ /* assert current thread holding state->main_lock */
+
+ const struct fsmonitor_batch *batch;
+ struct fsmonitor_batch *remainder;
+
+ if (!batch_marker)
+ return NULL;
+
+ trace_printf_key(&trace_fsmonitor, "Truncate: mark (%"PRIu64",%"PRIu64")",
+ batch_marker->batch_seq_nr,
+ (uint64_t)batch_marker->pinned_time);
+
+ for (batch = batch_marker; batch; batch = batch->next) {
+ time_t t;
+
+ if (!batch->pinned_time) /* an overflow batch */
+ continue;
+
+ t = batch->pinned_time + MY_TIME_DELAY_SECONDS;
+ if (t > batch_marker->pinned_time) /* too close to marker */
+ continue;
+
+ goto truncate_past_here;
+ }
+
+ return NULL;
+
+truncate_past_here:
+ state->current_token_data->batch_tail = (struct fsmonitor_batch *)batch;
+
+ remainder = ((struct fsmonitor_batch *)batch)->next;
+ ((struct fsmonitor_batch *)batch)->next = NULL;
+
+ return remainder;
+}
+
+static void fsmonitor_free_token_data(struct fsmonitor_token_data *token)
+{
+ if (!token)
+ return;
+
+ assert(token->client_ref_count == 0);
+
+ strbuf_release(&token->token_id);
+
+ fsmonitor_batch__free_list(token->batch_head);
+
+ free(token);
+}
+
+/*
+ * Flush all of our cached data about the filesystem. Call this if we
+ * lose sync with the filesystem and miss some notification events.
+ *
+ * [1] If we are missing events, then we no longer have a complete
+ * history of the directory (relative to our current start token).
+ * We should create a new token and start fresh (as if we just
+ * booted up).
+ *
+ * [2] Some of those lost events may have been for cookie files. We
+ * should assume the worst and abort them rather letting them starve.
+ *
+ * If there are no concurrent threads reading the current token data
+ * series, we can free it now. Otherwise, let the last reader free
+ * it.
+ *
+ * Either way, the old token data series is no longer associated with
+ * our state data.
+ */
+static void with_lock__do_force_resync(struct fsmonitor_daemon_state *state)
+{
+ /* assert current thread holding state->main_lock */
+
+ struct fsmonitor_token_data *free_me = NULL;
+ struct fsmonitor_token_data *new_one = NULL;
+
+ new_one = fsmonitor_new_token_data();
+
+ if (state->current_token_data->client_ref_count == 0)
+ free_me = state->current_token_data;
+ state->current_token_data = new_one;
+
+ fsmonitor_free_token_data(free_me);
+
+ with_lock__abort_all_cookies(state);
+}
+
+void fsmonitor_force_resync(struct fsmonitor_daemon_state *state)
+{
+ pthread_mutex_lock(&state->main_lock);
+ with_lock__do_force_resync(state);
+ pthread_mutex_unlock(&state->main_lock);
+}
+
+/*
+ * Format an opaque token string to send to the client.
+ */
+static void with_lock__format_response_token(
+ struct strbuf *response_token,
+ const struct strbuf *response_token_id,
+ const struct fsmonitor_batch *batch)
+{
+ /* assert current thread holding state->main_lock */
+
+ strbuf_reset(response_token);
+ strbuf_addf(response_token, "builtin:%s:%"PRIu64,
+ response_token_id->buf, batch->batch_seq_nr);
+}
+
+/*
+ * Parse an opaque token from the client.
+ * Returns -1 on error.
+ */
+static int fsmonitor_parse_client_token(const char *buf_token,
+ struct strbuf *requested_token_id,
+ uint64_t *seq_nr)
+{
+ const char *p;
+ char *p_end;
+
+ strbuf_reset(requested_token_id);
+ *seq_nr = 0;
+
+ if (!skip_prefix(buf_token, "builtin:", &p))
+ return -1;
+
+ while (*p && *p != ':')
+ strbuf_addch(requested_token_id, *p++);
+ if (!*p++)
+ return -1;
+
+ *seq_nr = (uint64_t)strtoumax(p, &p_end, 10);
+ if (*p_end)
+ return -1;
+
+ return 0;
+}
+
+KHASH_INIT(str, const char *, int, 0, kh_str_hash_func, kh_str_hash_equal)
+
+static int do_handle_client(struct fsmonitor_daemon_state *state,
+ const char *command,
+ ipc_server_reply_cb *reply,
+ struct ipc_server_reply_data *reply_data)
+{
+ struct fsmonitor_token_data *token_data = NULL;
+ struct strbuf response_token = STRBUF_INIT;
+ struct strbuf requested_token_id = STRBUF_INIT;
+ struct strbuf payload = STRBUF_INIT;
+ uint64_t requested_oldest_seq_nr = 0;
+ uint64_t total_response_len = 0;
+ const char *p;
+ const struct fsmonitor_batch *batch_head;
+ const struct fsmonitor_batch *batch;
+ struct fsmonitor_batch *remainder = NULL;
+ intmax_t count = 0, duplicates = 0;
+ kh_str_t *shown;
+ int hash_ret;
+ int do_trivial = 0;
+ int do_flush = 0;
+ int do_cookie = 0;
+ enum fsmonitor_cookie_item_result cookie_result;
+
+ /*
+ * We expect `command` to be of the form:
+ *
+ * <command> := quit NUL
+ * | flush NUL
+ * | <V1-time-since-epoch-ns> NUL
+ * | <V2-opaque-fsmonitor-token> NUL
+ */
+
+ if (!strcmp(command, "quit")) {
+ /*
+ * A client has requested over the socket/pipe that the
+ * daemon shutdown.
+ *
+ * Tell the IPC thread pool to shutdown (which completes
+ * the await in the main thread (which can stop the
+ * fsmonitor listener thread)).
+ *
+ * There is no reply to the client.
+ */
+ return SIMPLE_IPC_QUIT;
+
+ } else if (!strcmp(command, "flush")) {
+ /*
+ * Flush all of our cached data and generate a new token
+ * just like if we lost sync with the filesystem.
+ *
+ * Then send a trivial response using the new token.
+ */
+ do_flush = 1;
+ do_trivial = 1;
+
+ } else if (!skip_prefix(command, "builtin:", &p)) {
+ /* assume V1 timestamp or garbage */
+
+ char *p_end;
+
+ strtoumax(command, &p_end, 10);
+ trace_printf_key(&trace_fsmonitor,
+ ((*p_end) ?
+ "fsmonitor: invalid command line '%s'" :
+ "fsmonitor: unsupported V1 protocol '%s'"),
+ command);
+ do_trivial = 1;
+ do_cookie = 1;
+
+ } else {
+ /* We have "builtin:*" */
+ if (fsmonitor_parse_client_token(command, &requested_token_id,
+ &requested_oldest_seq_nr)) {
+ trace_printf_key(&trace_fsmonitor,
+ "fsmonitor: invalid V2 protocol token '%s'",
+ command);
+ do_trivial = 1;
+ do_cookie = 1;
+
+ } else {
+ /*
+ * We have a V2 valid token:
+ * "builtin:<token_id>:<seq_nr>"
+ */
+ do_cookie = 1;
+ }
+ }
+
+ pthread_mutex_lock(&state->main_lock);
+
+ if (!state->current_token_data)
+ BUG("fsmonitor state does not have a current token");
+
+ /*
+ * Write a cookie file inside the directory being watched in
+ * an effort to flush out existing filesystem events that we
+ * actually care about. Suspend this client thread until we
+ * see the filesystem events for this cookie file.
+ *
+ * Creating the cookie lets us guarantee that our FS listener
+ * thread has drained the kernel queue and we are caught up
+ * with the kernel.
+ *
+ * If we cannot create the cookie (or otherwise guarantee that
+ * we are caught up), we send a trivial response. We have to
+ * assume that there might be some very, very recent activity
+ * on the FS still in flight.
+ */
+ if (do_cookie) {
+ cookie_result = with_lock__wait_for_cookie(state);
+ if (cookie_result != FCIR_SEEN) {
+ error(_("fsmonitor: cookie_result '%d' != SEEN"),
+ cookie_result);
+ do_trivial = 1;
+ }
+ }
+
+ if (do_flush)
+ with_lock__do_force_resync(state);
+
+ /*
+ * We mark the current head of the batch list as "pinned" so
+ * that the listener thread will treat this item as read-only
+ * (and prevent any more paths from being added to it) from
+ * now on.
+ */
+ token_data = state->current_token_data;
+ batch_head = token_data->batch_head;
+ ((struct fsmonitor_batch *)batch_head)->pinned_time = time(NULL);
+
+ /*
+ * FSMonitor Protocol V2 requires that we send a response header
+ * with a "new current token" and then all of the paths that changed
+ * since the "requested token". We send the seq_nr of the just-pinned
+ * head batch so that future requests from a client will be relative
+ * to it.
+ */
+ with_lock__format_response_token(&response_token,
+ &token_data->token_id, batch_head);
+
+ reply(reply_data, response_token.buf, response_token.len + 1);
+ total_response_len += response_token.len + 1;
+
+ trace2_data_string("fsmonitor", the_repository, "response/token",
+ response_token.buf);
+ trace_printf_key(&trace_fsmonitor, "response token: %s",
+ response_token.buf);
+
+ if (!do_trivial) {
+ if (strcmp(requested_token_id.buf, token_data->token_id.buf)) {
+ /*
+ * The client last spoke to a different daemon
+ * instance -OR- the daemon had to resync with
+ * the filesystem (and lost events), so reject.
+ */
+ trace2_data_string("fsmonitor", the_repository,
+ "response/token", "different");
+ do_trivial = 1;
+
+ } else if (requested_oldest_seq_nr <
+ token_data->batch_tail->batch_seq_nr) {
+ /*
+ * The client wants older events than we have for
+ * this token_id. This means that the end of our
+ * batch list was truncated and we cannot give the
+ * client a complete snapshot relative to their
+ * request.
+ */
+ trace_printf_key(&trace_fsmonitor,
+ "client requested truncated data");
+ do_trivial = 1;
+ }
+ }
+
+ if (do_trivial) {
+ pthread_mutex_unlock(&state->main_lock);
+
+ reply(reply_data, "/", 2);
+
+ trace2_data_intmax("fsmonitor", the_repository,
+ "response/trivial", 1);
+
+ goto cleanup;
+ }
+
+ /*
+ * We're going to hold onto a pointer to the current
+ * token-data while we walk the list of batches of files.
+ * During this time, we will NOT be under the lock.
+ * So we ref-count it.
+ *
+ * This allows the listener thread to continue prepending
+ * new batches of items to the token-data (which we'll ignore).
+ *
+ * AND it allows the listener thread to do a token-reset
+ * (and install a new `current_token_data`).
+ */
+ token_data->client_ref_count++;
+
+ pthread_mutex_unlock(&state->main_lock);
+
+ /*
+ * The client request is relative to the token that they sent,
+ * so walk the batch list backwards from the current head back
+ * to the batch (sequence number) they named.
+ *
+ * We use khash to de-dup the list of pathnames.
+ *
+ * NEEDSWORK: each batch contains a list of interned strings,
+ * so we only need to do pointer comparisons here to build the
+ * hash table. Currently, we're still comparing the string
+ * values.
+ */
+ shown = kh_init_str();
+ for (batch = batch_head;
+ batch && batch->batch_seq_nr > requested_oldest_seq_nr;
+ batch = batch->next) {
+ size_t k;
+
+ for (k = 0; k < batch->nr; k++) {
+ const char *s = batch->interned_paths[k];
+ size_t s_len;
+
+ if (kh_get_str(shown, s) != kh_end(shown))
+ duplicates++;
+ else {
+ kh_put_str(shown, s, &hash_ret);
+
+ trace_printf_key(&trace_fsmonitor,
+ "send[%"PRIuMAX"]: %s",
+ count, s);
+
+ /* Each path gets written with a trailing NUL */
+ s_len = strlen(s) + 1;
+
+ if (payload.len + s_len >=
+ LARGE_PACKET_DATA_MAX) {
+ reply(reply_data, payload.buf,
+ payload.len);
+ total_response_len += payload.len;
+ strbuf_reset(&payload);
+ }
+
+ strbuf_add(&payload, s, s_len);
+ count++;
+ }
+ }
+ }
+
+ if (payload.len) {
+ reply(reply_data, payload.buf, payload.len);
+ total_response_len += payload.len;
+ }
+
+ kh_release_str(shown);
+
+ pthread_mutex_lock(&state->main_lock);
+
+ if (token_data->client_ref_count > 0)
+ token_data->client_ref_count--;
+
+ if (token_data->client_ref_count == 0) {
+ if (token_data != state->current_token_data) {
+ /*
+ * The listener thread did a token-reset while we were
+ * walking the batch list. Therefore, this token is
+ * stale and can be discarded completely. If we are
+ * the last reader thread using this token, we own
+ * that work.
+ */
+ fsmonitor_free_token_data(token_data);
+ } else if (batch) {
+ /*
+ * We are holding the lock and are the only
+ * reader of the ref-counted portion of the
+ * list, so we get the honor of seeing if the
+ * list can be truncated to save memory.
+ *
+ * The main loop did not walk to the end of the
+ * list, so this batch is the first item in the
+ * batch-list that is older than the requested
+ * end-point sequence number. See if the tail
+ * end of the list is obsolete.
+ */
+ remainder = with_lock__truncate_old_batches(state,
+ batch);
+ }
+ }
+
+ pthread_mutex_unlock(&state->main_lock);
+
+ if (remainder)
+ fsmonitor_batch__free_list(remainder);
+
+ trace2_data_intmax("fsmonitor", the_repository, "response/length", total_response_len);
+ trace2_data_intmax("fsmonitor", the_repository, "response/count/files", count);
+ trace2_data_intmax("fsmonitor", the_repository, "response/count/duplicates", duplicates);
+
+cleanup:
+ strbuf_release(&response_token);
+ strbuf_release(&requested_token_id);
+ strbuf_release(&payload);
+
+ return 0;
+}
+
+static ipc_server_application_cb handle_client;
+
+static int handle_client(void *data,
+ const char *command, size_t command_len,
+ ipc_server_reply_cb *reply,
+ struct ipc_server_reply_data *reply_data)
+{
+ struct fsmonitor_daemon_state *state = data;
+ int result;
+
+ /*
+ * The Simple IPC API now supports {char*, len} arguments, but
+ * FSMonitor always uses proper null-terminated strings, so
+ * we can ignore the command_len argument. (Trust, but verify.)
+ */
+ if (command_len != strlen(command))
+ BUG("FSMonitor assumes text messages");
+
+ trace_printf_key(&trace_fsmonitor, "requested token: %s", command);
+
+ trace2_region_enter("fsmonitor", "handle_client", the_repository);
+ trace2_data_string("fsmonitor", the_repository, "request", command);
+
+ result = do_handle_client(state, command, reply, reply_data);
+
+ trace2_region_leave("fsmonitor", "handle_client", the_repository);
+
+ return result;
+}
+
+#define FSMONITOR_DIR "fsmonitor--daemon"
+#define FSMONITOR_COOKIE_DIR "cookies"
+#define FSMONITOR_COOKIE_PREFIX (FSMONITOR_DIR "/" FSMONITOR_COOKIE_DIR "/")
+
+enum fsmonitor_path_type fsmonitor_classify_path_workdir_relative(
+ const char *rel)
+{
+ if (fspathncmp(rel, ".git", 4))
+ return IS_WORKDIR_PATH;
+ rel += 4;
+
+ if (!*rel)
+ return IS_DOT_GIT;
+ if (*rel != '/')
+ return IS_WORKDIR_PATH; /* e.g. .gitignore */
+ rel++;
+
+ if (!fspathncmp(rel, FSMONITOR_COOKIE_PREFIX,
+ strlen(FSMONITOR_COOKIE_PREFIX)))
+ return IS_INSIDE_DOT_GIT_WITH_COOKIE_PREFIX;
+
+ return IS_INSIDE_DOT_GIT;
+}
+
+enum fsmonitor_path_type fsmonitor_classify_path_gitdir_relative(
+ const char *rel)
+{
+ if (!fspathncmp(rel, FSMONITOR_COOKIE_PREFIX,
+ strlen(FSMONITOR_COOKIE_PREFIX)))
+ return IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX;
+
+ return IS_INSIDE_GITDIR;
+}
+
+static enum fsmonitor_path_type try_classify_workdir_abs_path(
+ struct fsmonitor_daemon_state *state,
+ const char *path)
+{
+ const char *rel;
+
+ if (fspathncmp(path, state->path_worktree_watch.buf,
+ state->path_worktree_watch.len))
+ return IS_OUTSIDE_CONE;
+
+ rel = path + state->path_worktree_watch.len;
+
+ if (!*rel)
+ return IS_WORKDIR_PATH; /* it is the root dir exactly */
+ if (*rel != '/')
+ return IS_OUTSIDE_CONE;
+ rel++;
+
+ return fsmonitor_classify_path_workdir_relative(rel);
+}
+
+enum fsmonitor_path_type fsmonitor_classify_path_absolute(
+ struct fsmonitor_daemon_state *state,
+ const char *path)
+{
+ const char *rel;
+ enum fsmonitor_path_type t;
+
+ t = try_classify_workdir_abs_path(state, path);
+ if (state->nr_paths_watching == 1)
+ return t;
+ if (t != IS_OUTSIDE_CONE)
+ return t;
+
+ if (fspathncmp(path, state->path_gitdir_watch.buf,
+ state->path_gitdir_watch.len))
+ return IS_OUTSIDE_CONE;
+
+ rel = path + state->path_gitdir_watch.len;
+
+ if (!*rel)
+ return IS_GITDIR; /* it is the <gitdir> exactly */
+ if (*rel != '/')
+ return IS_OUTSIDE_CONE;
+ rel++;
+
+ return fsmonitor_classify_path_gitdir_relative(rel);
+}
+
+/*
+ * We try to combine small batches at the front of the batch-list to avoid
+ * having a long list. This hopefully makes it a little easier when we want
+ * to truncate and maintain the list. However, we don't want the paths array
+ * to just keep growing and growing with realloc, so we insert an arbitrary
+ * limit.
+ */
+#define MY_COMBINE_LIMIT (1024)
+
+void fsmonitor_publish(struct fsmonitor_daemon_state *state,
+ struct fsmonitor_batch *batch,
+ const struct string_list *cookie_names)
+{
+ if (!batch && !cookie_names->nr)
+ return;
+
+ pthread_mutex_lock(&state->main_lock);
+
+ if (batch) {
+ struct fsmonitor_batch *head;
+
+ head = state->current_token_data->batch_head;
+ if (!head) {
+ BUG("token does not have batch");
+ } else if (head->pinned_time) {
+ /*
+ * We cannot alter the current batch list
+ * because:
+ *
+ * [a] it is being transmitted to at least one
+ * client and the handle_client() thread has a
+ * ref-count, but not a lock on the batch list
+ * starting with this item.
+ *
+ * [b] it has been transmitted in the past to
+ * at least one client such that future
+ * requests are relative to this head batch.
+ *
+ * So, we can only prepend a new batch onto
+ * the front of the list.
+ */
+ batch->batch_seq_nr = head->batch_seq_nr + 1;
+ batch->next = head;
+ state->current_token_data->batch_head = batch;
+ } else if (!head->batch_seq_nr) {
+ /*
+ * Batch 0 is unpinned. See the note in
+ * `fsmonitor_new_token_data()` about why we
+ * don't need to accumulate these paths.
+ */
+ fsmonitor_batch__free_list(batch);
+ } else if (head->nr + batch->nr > MY_COMBINE_LIMIT) {
+ /*
+ * The head batch in the list has never been
+ * transmitted to a client, but folding the
+ * contents of the new batch onto it would
+ * exceed our arbitrary limit, so just prepend
+ * the new batch onto the list.
+ */
+ batch->batch_seq_nr = head->batch_seq_nr + 1;
+ batch->next = head;
+ state->current_token_data->batch_head = batch;
+ } else {
+ /*
+ * We are free to add the paths in the given
+ * batch onto the end of the current head batch.
+ */
+ fsmonitor_batch__combine(head, batch);
+ fsmonitor_batch__free_list(batch);
+ }
+ }
+
+ if (cookie_names->nr)
+ with_lock__mark_cookies_seen(state, cookie_names);
+
+ pthread_mutex_unlock(&state->main_lock);
+}
+
+static void *fsm_health__thread_proc(void *_state)
+{
+ struct fsmonitor_daemon_state *state = _state;
+
+ trace2_thread_start("fsm-health");
+
+ fsm_health__loop(state);
+
+ trace2_thread_exit();
+ return NULL;
+}
+
+static void *fsm_listen__thread_proc(void *_state)
+{
+ struct fsmonitor_daemon_state *state = _state;
+
+ trace2_thread_start("fsm-listen");
+
+ trace_printf_key(&trace_fsmonitor, "Watching: worktree '%s'",
+ state->path_worktree_watch.buf);
+ if (state->nr_paths_watching > 1)
+ trace_printf_key(&trace_fsmonitor, "Watching: gitdir '%s'",
+ state->path_gitdir_watch.buf);
+
+ fsm_listen__loop(state);
+
+ pthread_mutex_lock(&state->main_lock);
+ if (state->current_token_data &&
+ state->current_token_data->client_ref_count == 0)
+ fsmonitor_free_token_data(state->current_token_data);
+ state->current_token_data = NULL;
+ pthread_mutex_unlock(&state->main_lock);
+
+ trace2_thread_exit();
+ return NULL;
+}
+
+static int fsmonitor_run_daemon_1(struct fsmonitor_daemon_state *state)
+{
+ struct ipc_server_opts ipc_opts = {
+ .nr_threads = fsmonitor__ipc_threads,
+
+ /*
+ * We know that there are no other active threads yet,
+ * so we can let the IPC layer temporarily chdir() if
+ * it needs to when creating the server side of the
+ * Unix domain socket.
+ */
+ .uds_disallow_chdir = 0
+ };
+ int health_started = 0;
+ int listener_started = 0;
+ int err = 0;
+
+ /*
+ * Start the IPC thread pool before the we've started the file
+ * system event listener thread so that we have the IPC handle
+ * before we need it.
+ */
+ if (ipc_server_run_async(&state->ipc_server_data,
+ state->path_ipc.buf, &ipc_opts,
+ handle_client, state))
+ return error_errno(
+ _("could not start IPC thread pool on '%s'"),
+ state->path_ipc.buf);
+
+ /*
+ * Start the fsmonitor listener thread to collect filesystem
+ * events.
+ */
+ if (pthread_create(&state->listener_thread, NULL,
+ fsm_listen__thread_proc, state)) {
+ ipc_server_stop_async(state->ipc_server_data);
+ err = error(_("could not start fsmonitor listener thread"));
+ goto cleanup;
+ }
+ listener_started = 1;
+
+ /*
+ * Start the health thread to watch over our process.
+ */
+ if (pthread_create(&state->health_thread, NULL,
+ fsm_health__thread_proc, state)) {
+ ipc_server_stop_async(state->ipc_server_data);
+ err = error(_("could not start fsmonitor health thread"));
+ goto cleanup;
+ }
+ health_started = 1;
+
+ /*
+ * The daemon is now fully functional in background threads.
+ * Our primary thread should now just wait while the threads
+ * do all the work.
+ */
+cleanup:
+ /*
+ * Wait for the IPC thread pool to shutdown (whether by client
+ * request, from filesystem activity, or an error).
+ */
+ ipc_server_await(state->ipc_server_data);
+
+ /*
+ * The fsmonitor listener thread may have received a shutdown
+ * event from the IPC thread pool, but it doesn't hurt to tell
+ * it again. And wait for it to shutdown.
+ */
+ if (listener_started) {
+ fsm_listen__stop_async(state);
+ pthread_join(state->listener_thread, NULL);
+ }
+
+ if (health_started) {
+ fsm_health__stop_async(state);
+ pthread_join(state->health_thread, NULL);
+ }
+
+ if (err)
+ return err;
+ if (state->listen_error_code)
+ return state->listen_error_code;
+ if (state->health_error_code)
+ return state->health_error_code;
+ return 0;
+}
+
+static int fsmonitor_run_daemon(void)
+{
+ struct fsmonitor_daemon_state state;
+ const char *home;
+ int err;
+
+ memset(&state, 0, sizeof(state));
+
+ hashmap_init(&state.cookies, cookies_cmp, NULL, 0);
+ pthread_mutex_init(&state.main_lock, NULL);
+ pthread_cond_init(&state.cookies_cond, NULL);
+ state.listen_error_code = 0;
+ state.health_error_code = 0;
+ state.current_token_data = fsmonitor_new_token_data();
+
+ /* Prepare to (recursively) watch the <worktree-root> directory. */
+ strbuf_init(&state.path_worktree_watch, 0);
+ 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
+ * ".git" is not a directory, then <gitdir> is not inside the
+ * cone of <worktree-root>, so set up a second watch to watch
+ * the <gitdir> so that we get events for the cookie files.
+ */
+ strbuf_init(&state.path_gitdir_watch, 0);
+ strbuf_addbuf(&state.path_gitdir_watch, &state.path_worktree_watch);
+ strbuf_addstr(&state.path_gitdir_watch, "/.git");
+ if (!is_directory(state.path_gitdir_watch.buf)) {
+ strbuf_reset(&state.path_gitdir_watch);
+ strbuf_addstr(&state.path_gitdir_watch, absolute_path(get_git_dir()));
+ state.nr_paths_watching = 2;
+ }
+
+ /*
+ * We will write filesystem syncing cookie files into
+ * <gitdir>/<fsmonitor-dir>/<cookie-dir>/<pid>-<seq>.
+ *
+ * The extra layers of subdirectories here keep us from
+ * changing the mtime on ".git/" or ".git/foo/" when we create
+ * or delete cookie files.
+ *
+ * There have been problems with some IDEs that do a
+ * non-recursive watch of the ".git/" directory and run a
+ * series of commands any time something happens.
+ *
+ * For example, if we place our cookie files directly in
+ * ".git/" or ".git/foo/" then a `git status` (or similar
+ * command) from the IDE will cause a cookie file to be
+ * created in one of those dirs. This causes the mtime of
+ * those dirs to change. This triggers the IDE's watch
+ * notification. This triggers the IDE to run those commands
+ * again. And the process repeats and the machine never goes
+ * idle.
+ *
+ * Adding the extra layers of subdirectories prevents the
+ * mtime of ".git/" and ".git/foo" from changing when a
+ * cookie file is created.
+ */
+ strbuf_init(&state.path_cookie_prefix, 0);
+ strbuf_addbuf(&state.path_cookie_prefix, &state.path_gitdir_watch);
+
+ strbuf_addch(&state.path_cookie_prefix, '/');
+ strbuf_addstr(&state.path_cookie_prefix, FSMONITOR_DIR);
+ mkdir(state.path_cookie_prefix.buf, 0777);
+
+ strbuf_addch(&state.path_cookie_prefix, '/');
+ strbuf_addstr(&state.path_cookie_prefix, FSMONITOR_COOKIE_DIR);
+ mkdir(state.path_cookie_prefix.buf, 0777);
+
+ strbuf_addch(&state.path_cookie_prefix, '/');
+
+ /*
+ * We create a named-pipe or unix domain socket inside of the
+ * ".git" directory. (Well, on Windows, we base our named
+ * pipe in the NPFS on the absolute path of the git
+ * directory.)
+ */
+ strbuf_init(&state.path_ipc, 0);
+ strbuf_addstr(&state.path_ipc,
+ absolute_path(fsmonitor_ipc__get_path(the_repository)));
+
+ /*
+ * Confirm that we can create platform-specific resources for the
+ * filesystem listener before we bother starting all the threads.
+ */
+ if (fsm_listen__ctor(&state)) {
+ err = error(_("could not initialize listener thread"));
+ goto done;
+ }
+
+ if (fsm_health__ctor(&state)) {
+ err = error(_("could not initialize health thread"));
+ goto done;
+ }
+
+ /*
+ * CD out of the worktree root directory.
+ *
+ * The common Git startup mechanism causes our CWD to be the
+ * root of the worktree. On Windows, this causes our process
+ * to hold a locked handle on the CWD. This prevents the
+ * worktree from being moved or deleted while the daemon is
+ * running.
+ *
+ * We assume that our FS and IPC listener threads have either
+ * opened all of the handles that they need or will do
+ * everything using absolute paths.
+ */
+ home = getenv("HOME");
+ if (home && *home && chdir(home))
+ die_errno(_("could not cd home '%s'"), home);
+
+ err = fsmonitor_run_daemon_1(&state);
+
+done:
+ pthread_cond_destroy(&state.cookies_cond);
+ pthread_mutex_destroy(&state.main_lock);
+ fsm_listen__dtor(&state);
+ fsm_health__dtor(&state);
+
+ ipc_server_free(state.ipc_server_data);
+
+ strbuf_release(&state.path_worktree_watch);
+ 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;
+}
+
+static int try_to_run_foreground_daemon(int detach_console MAYBE_UNUSED)
+{
+ /*
+ * Technically, we don't need to probe for an existing daemon
+ * process, since we could just call `fsmonitor_run_daemon()`
+ * and let it fail if the pipe/socket is busy.
+ *
+ * However, this method gives us a nicer error message for a
+ * common error case.
+ */
+ if (fsmonitor_ipc__get_state() == IPC_STATE__LISTENING)
+ die(_("fsmonitor--daemon is already running '%s'"),
+ the_repository->worktree);
+
+ if (fsmonitor__announce_startup) {
+ fprintf(stderr, _("running fsmonitor-daemon in '%s'\n"),
+ the_repository->worktree);
+ fflush(stderr);
+ }
+
+#ifdef GIT_WINDOWS_NATIVE
+ if (detach_console)
+ FreeConsole();
+#endif
+
+ return !!fsmonitor_run_daemon();
+}
+
+static start_bg_wait_cb bg_wait_cb;
+
+static int bg_wait_cb(const struct child_process *cp UNUSED,
+ void *cb_data UNUSED)
+{
+ enum ipc_active_state s = fsmonitor_ipc__get_state();
+
+ switch (s) {
+ case IPC_STATE__LISTENING:
+ /* child is "ready" */
+ return 0;
+
+ case IPC_STATE__NOT_LISTENING:
+ case IPC_STATE__PATH_NOT_FOUND:
+ /* give child more time */
+ return 1;
+
+ default:
+ case IPC_STATE__INVALID_PATH:
+ case IPC_STATE__OTHER_ERROR:
+ /* all the time in world won't help */
+ return -1;
+ }
+}
+
+static int try_to_start_background_daemon(void)
+{
+ struct child_process cp = CHILD_PROCESS_INIT;
+ enum start_bg_result sbgr;
+
+ /*
+ * Before we try to create a background daemon process, see
+ * if a daemon process is already listening. This makes it
+ * easier for us to report an already-listening error to the
+ * console, since our spawn/daemon can only report the success
+ * of creating the background process (and not whether it
+ * immediately exited).
+ */
+ if (fsmonitor_ipc__get_state() == IPC_STATE__LISTENING)
+ die(_("fsmonitor--daemon is already running '%s'"),
+ the_repository->worktree);
+
+ if (fsmonitor__announce_startup) {
+ fprintf(stderr, _("starting fsmonitor-daemon in '%s'\n"),
+ the_repository->worktree);
+ fflush(stderr);
+ }
+
+ cp.git_cmd = 1;
+
+ strvec_push(&cp.args, "fsmonitor--daemon");
+ strvec_push(&cp.args, "run");
+ strvec_push(&cp.args, "--detach");
+ strvec_pushf(&cp.args, "--ipc-threads=%d", fsmonitor__ipc_threads);
+
+ cp.no_stdin = 1;
+ cp.no_stdout = 1;
+ cp.no_stderr = 1;
+
+ sbgr = start_bg_command(&cp, bg_wait_cb, NULL,
+ fsmonitor__start_timeout_sec);
+
+ switch (sbgr) {
+ case SBGR_READY:
+ return 0;
+
+ default:
+ case SBGR_ERROR:
+ case SBGR_CB_ERROR:
+ return error(_("daemon failed to start"));
+
+ case SBGR_TIMEOUT:
+ return error(_("daemon not online yet"));
+
+ case SBGR_DIED:
+ return error(_("daemon terminated"));
+ }
+}
+
+int cmd_fsmonitor__daemon(int argc, const char **argv, const char *prefix)
+{
+ const char *subcmd;
+ enum fsmonitor_reason reason;
+ int detach_console = 0;
+
+ struct option options[] = {
+ OPT_BOOL(0, "detach", &detach_console, N_("detach from console")),
+ OPT_INTEGER(0, "ipc-threads",
+ &fsmonitor__ipc_threads,
+ N_("use <n> ipc worker threads")),
+ OPT_INTEGER(0, "start-timeout",
+ &fsmonitor__start_timeout_sec,
+ N_("max seconds to wait for background daemon startup")),
+
+ OPT_END()
+ };
+
+ git_config(fsmonitor_config, NULL);
+
+ argc = parse_options(argc, argv, prefix, options,
+ builtin_fsmonitor__daemon_usage, 0);
+ if (argc != 1)
+ usage_with_options(builtin_fsmonitor__daemon_usage, options);
+ subcmd = argv[0];
+
+ if (fsmonitor__ipc_threads < 1)
+ die(_("invalid 'ipc-threads' value (%d)"),
+ fsmonitor__ipc_threads);
+
+ prepare_repo_settings(the_repository);
+ /*
+ * If the repo is fsmonitor-compatible, explicitly set IPC-mode
+ * (without bothering to load the `core.fsmonitor` config settings).
+ *
+ * If the repo is not compatible, the repo-settings will be set to
+ * incompatible rather than IPC, so we can use one of the __get
+ * routines to detect the discrepancy.
+ */
+ fsm_settings__set_ipc(the_repository);
+
+ reason = fsm_settings__get_reason(the_repository);
+ if (reason > FSMONITOR_REASON_OK)
+ die("%s",
+ fsm_settings__get_incompatible_msg(the_repository,
+ reason));
+
+ if (!strcmp(subcmd, "start"))
+ return !!try_to_start_background_daemon();
+
+ if (!strcmp(subcmd, "run"))
+ return !!try_to_run_foreground_daemon(detach_console);
+
+ if (!strcmp(subcmd, "stop"))
+ return !!do_as_client__send_stop();
+
+ if (!strcmp(subcmd, "status"))
+ return !!do_as_client__status();
+
+ die(_("Unhandled subcommand '%s'"), subcmd);
+}
+
+#else
+int cmd_fsmonitor__daemon(int argc, const char **argv, const char *prefix UNUSED)
+{
+ struct option options[] = {
+ OPT_END()
+ };
+
+ if (argc == 2 && !strcmp(argv[1], "-h"))
+ usage_with_options(builtin_fsmonitor__daemon_usage, options);
+
+ die(_("fsmonitor--daemon not supported on this platform"));
+}
+#endif