Git Source Code Mirror - This is a publish-only repository and all pull requests are ignored. Please follow Documentation/SubmittingPatches procedure for any of your improvements. https://git-scm.com/
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 
git/builtin/fsmonitor--daemon.c

1577 lines
44 KiB

#include "builtin.h"
#include "config.h"
#include "parse-options.h"
#include "fsmonitor.h"
#include "fsmonitor-ipc.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"
static const char * const builtin_fsmonitor__daemon_usage[] = {
N_("git fsmonitor--daemon start [<options>]"),
N_("git fsmonitor--daemon run [<options>]"),
N_("git fsmonitor--daemon stop"),
N_("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, void *cb)
{
if (!strcmp(var, FSMONITOR__IPC_THREADS)) {
int i = git_config_int(var, value);
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);
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, &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, 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, 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;
} 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;
} 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) < 0) {
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) < 0) {
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;
/*
* 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()));
/*
* 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);
return err;
}
static int try_to_run_foreground_daemon(int detach_console)
{
/*
* 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, void *cb_data)
{
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)
{
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