+struct stats_details {
+ void (*done)(char *data, void *u);
+ void *u;
+ int exited; /* subprocess exited */
+ int closed; /* pipe close */
+ int wstat; /* wait status from subprocess */
+ struct dynstr data[1]; /* data read from pipe */
+};
+
+static void stats_complete(struct stats_details *d) {
+ char *s;
+
+ if(!(d->exited && d->closed))
+ return;
+ byte_xasprintf(&s, "\n"
+ "Server stats:\n"
+ "track lookup cache hits: %lu\n"
+ "track lookup cache misses: %lu\n",
+ cache_files_hits,
+ cache_files_misses);
+ dynstr_append_string(d->data, s);
+ dynstr_terminate(d->data);
+ d->done(d->data->vec, d->u);
+}
+
+static int stats_finished(ev_source attribute((unused)) *ev,
+ pid_t attribute((unused)) pid,
+ int status,
+ const struct rusage attribute((unused)) *rusage,
+ void *u) {
+ struct stats_details *const d = u;
+
+ d->exited = 1;
+ if(status)
+ error(0, "disorder-stats %s", wstat(status));
+ stats_complete(d);
+ return 0;
+}
+
+static int stats_read(ev_source attribute((unused)) *ev,
+ ev_reader *reader,
+ void *ptr,
+ size_t bytes,
+ int eof,
+ void *u) {
+ struct stats_details *const d = u;
+
+ dynstr_append_bytes(d->data, ptr, bytes);
+ ev_reader_consume(reader, bytes);
+ if(eof)
+ d->closed = 1;
+ stats_complete(d);
+ return 0;
+}
+
+static int stats_error(ev_source attribute((unused)) *ev,
+ int errno_value,
+ void *u) {
+ struct stats_details *const d = u;
+
+ error(errno_value, "error reading from pipe to disorder-stats");
+ d->closed = 1;
+ stats_complete(d);
+ return 0;
+}
+
+void trackdb_stats_subprocess(ev_source *ev,
+ void (*done)(char *data, void *u),
+ void *u) {
+ int p[2];
+ pid_t pid;
+ struct stats_details *d = xmalloc(sizeof *d);
+
+ dynstr_init(d->data);
+ d->done = done;
+ d->u = u;
+ xpipe(p);
+ pid = subprogram(ev, "disorder-stats", p[1]);
+ xclose(p[1]);
+ ev_child(ev, pid, 0, stats_finished, d);
+ ev_reader_new(ev, p[0], stats_read, stats_error, d, "disorder-stats reader");
+}
+