1edb47ec4SLluís /* 2edb47ec4SLluís * Simple trace backend 3edb47ec4SLluís * 4edb47ec4SLluís * Copyright IBM, Corp. 2010 5edb47ec4SLluís * 6edb47ec4SLluís * This work is licensed under the terms of the GNU GPL, version 2. See 7edb47ec4SLluís * the COPYING file in the top-level directory. 8edb47ec4SLluís * 9edb47ec4SLluís */ 10edb47ec4SLluís 11edb47ec4SLluís #include <stdlib.h> 12edb47ec4SLluís #include <stdint.h> 13edb47ec4SLluís #include <stdio.h> 14edb47ec4SLluís #include <time.h> 1585aff158SStefan Hajnoczi #ifndef _WIN32 16edb47ec4SLluís #include <signal.h> 17edb47ec4SLluís #include <pthread.h> 1885aff158SStefan Hajnoczi #endif 191de7afc9SPaolo Bonzini #include "qemu/timer.h" 20edb47ec4SLluís #include "trace.h" 21e4858974SLluís #include "trace/control.h" 22b618c288SLluís Vilanova #include "trace/simple.h" 23edb47ec4SLluís 24edb47ec4SLluís /** Trace file header event ID */ 25edb47ec4SLluís #define HEADER_EVENT_ID (~(uint64_t)0) /* avoids conflicting with TraceEventIDs */ 26edb47ec4SLluís 27edb47ec4SLluís /** Trace file magic number */ 28edb47ec4SLluís #define HEADER_MAGIC 0xf2b177cb0aa429b4ULL 29edb47ec4SLluís 30edb47ec4SLluís /** Trace file version number, bump if format changes */ 31ef0bd3bbSLluís Vilanova #define HEADER_VERSION 3 32edb47ec4SLluís 33edb47ec4SLluís /** Records were dropped event ID */ 34edb47ec4SLluís #define DROPPED_EVENT_ID (~(uint64_t)0 - 1) 35edb47ec4SLluís 36edb47ec4SLluís /** Trace record is valid */ 37edb47ec4SLluís #define TRACE_RECORD_VALID ((uint64_t)1 << 63) 38edb47ec4SLluís 39edb47ec4SLluís /* 40edb47ec4SLluís * Trace records are written out by a dedicated thread. The thread waits for 41edb47ec4SLluís * records to become available, writes them out, and then waits again. 42edb47ec4SLluís */ 4386946a2dSMichael Tokarev static CompatGMutex trace_lock; 4486946a2dSMichael Tokarev static CompatGCond trace_available_cond; 4586946a2dSMichael Tokarev static CompatGCond trace_empty_cond; 464a0e6714SStefan Hajnoczi 47edb47ec4SLluís static bool trace_available; 48edb47ec4SLluís static bool trace_writeout_enabled; 49edb47ec4SLluís 5062bab732SHarsh Prateek Bora enum { 5162bab732SHarsh Prateek Bora TRACE_BUF_LEN = 4096 * 64, 5262bab732SHarsh Prateek Bora TRACE_BUF_FLUSH_THRESHOLD = TRACE_BUF_LEN / 4, 5362bab732SHarsh Prateek Bora }; 5462bab732SHarsh Prateek Bora 5562bab732SHarsh Prateek Bora uint8_t trace_buf[TRACE_BUF_LEN]; 5630d94087SStefan Hajnoczi static volatile gint trace_idx; 5762bab732SHarsh Prateek Bora static unsigned int writeout_idx; 5830d94087SStefan Hajnoczi static volatile gint dropped_events; 5926896cbfSStefan Hajnoczi static uint32_t trace_pid; 60edb47ec4SLluís static FILE *trace_fp; 614552e410SStefan Weil static char *trace_file_name; 62edb47ec4SLluís 6362bab732SHarsh Prateek Bora /* * Trace buffer entry */ 6462bab732SHarsh Prateek Bora typedef struct { 6562bab732SHarsh Prateek Bora uint64_t event; /* TraceEventID */ 6662bab732SHarsh Prateek Bora uint64_t timestamp_ns; 6762bab732SHarsh Prateek Bora uint32_t length; /* in bytes */ 6826896cbfSStefan Hajnoczi uint32_t pid; 69fb3a5085SMarkus Armbruster uint64_t arguments[]; 7062bab732SHarsh Prateek Bora } TraceRecord; 7162bab732SHarsh Prateek Bora 7262bab732SHarsh Prateek Bora typedef struct { 7362bab732SHarsh Prateek Bora uint64_t header_event_id; /* HEADER_EVENT_ID */ 7462bab732SHarsh Prateek Bora uint64_t header_magic; /* HEADER_MAGIC */ 7562bab732SHarsh Prateek Bora uint64_t header_version; /* HEADER_VERSION */ 768ae601e8SHarsh Prateek Bora } TraceLogHeader; 7762bab732SHarsh Prateek Bora 7862bab732SHarsh Prateek Bora 7962bab732SHarsh Prateek Bora static void read_from_buffer(unsigned int idx, void *dataptr, size_t size); 8062bab732SHarsh Prateek Bora static unsigned int write_to_buffer(unsigned int idx, void *dataptr, size_t size); 8162bab732SHarsh Prateek Bora 8262bab732SHarsh Prateek Bora static void clear_buffer_range(unsigned int idx, size_t len) 8362bab732SHarsh Prateek Bora { 8462bab732SHarsh Prateek Bora uint32_t num = 0; 8562bab732SHarsh Prateek Bora while (num < len) { 8662bab732SHarsh Prateek Bora if (idx >= TRACE_BUF_LEN) { 8762bab732SHarsh Prateek Bora idx = idx % TRACE_BUF_LEN; 8862bab732SHarsh Prateek Bora } 8962bab732SHarsh Prateek Bora trace_buf[idx++] = 0; 9062bab732SHarsh Prateek Bora num++; 9162bab732SHarsh Prateek Bora } 9262bab732SHarsh Prateek Bora } 93edb47ec4SLluís /** 94edb47ec4SLluís * Read a trace record from the trace buffer 95edb47ec4SLluís * 96edb47ec4SLluís * @idx Trace buffer index 97edb47ec4SLluís * @record Trace record to fill 98edb47ec4SLluís * 99edb47ec4SLluís * Returns false if the record is not valid. 100edb47ec4SLluís */ 10162bab732SHarsh Prateek Bora static bool get_trace_record(unsigned int idx, TraceRecord **recordptr) 102edb47ec4SLluís { 10362bab732SHarsh Prateek Bora uint64_t event_flag = 0; 10462bab732SHarsh Prateek Bora TraceRecord record; 10562bab732SHarsh Prateek Bora /* read the event flag to see if its a valid record */ 10662bab732SHarsh Prateek Bora read_from_buffer(idx, &record, sizeof(event_flag)); 10762bab732SHarsh Prateek Bora 10862bab732SHarsh Prateek Bora if (!(record.event & TRACE_RECORD_VALID)) { 109edb47ec4SLluís return false; 110edb47ec4SLluís } 111edb47ec4SLluís 11262bab732SHarsh Prateek Bora smp_rmb(); /* read memory barrier before accessing record */ 11362bab732SHarsh Prateek Bora /* read the record header to know record length */ 11462bab732SHarsh Prateek Bora read_from_buffer(idx, &record, sizeof(TraceRecord)); 11562bab732SHarsh Prateek Bora *recordptr = malloc(record.length); /* dont use g_malloc, can deadlock when traced */ 11662bab732SHarsh Prateek Bora /* make a copy of record to avoid being overwritten */ 11762bab732SHarsh Prateek Bora read_from_buffer(idx, *recordptr, record.length); 11862bab732SHarsh Prateek Bora smp_rmb(); /* memory barrier before clearing valid flag */ 11962bab732SHarsh Prateek Bora (*recordptr)->event &= ~TRACE_RECORD_VALID; 12062bab732SHarsh Prateek Bora /* clear the trace buffer range for consumed record otherwise any byte 12162bab732SHarsh Prateek Bora * with its MSB set may be considered as a valid event id when the writer 12262bab732SHarsh Prateek Bora * thread crosses this range of buffer again. 12362bab732SHarsh Prateek Bora */ 12462bab732SHarsh Prateek Bora clear_buffer_range(idx, record.length); 125edb47ec4SLluís return true; 126edb47ec4SLluís } 127edb47ec4SLluís 128edb47ec4SLluís /** 129edb47ec4SLluís * Kick writeout thread 130edb47ec4SLluís * 131edb47ec4SLluís * @wait Whether to wait for writeout thread to complete 132edb47ec4SLluís */ 133edb47ec4SLluís static void flush_trace_file(bool wait) 134edb47ec4SLluís { 13586946a2dSMichael Tokarev g_mutex_lock(&trace_lock); 136edb47ec4SLluís trace_available = true; 13786946a2dSMichael Tokarev g_cond_signal(&trace_available_cond); 138edb47ec4SLluís 139edb47ec4SLluís if (wait) { 14086946a2dSMichael Tokarev g_cond_wait(&trace_empty_cond, &trace_lock); 141edb47ec4SLluís } 142edb47ec4SLluís 14386946a2dSMichael Tokarev g_mutex_unlock(&trace_lock); 144edb47ec4SLluís } 145edb47ec4SLluís 146edb47ec4SLluís static void wait_for_trace_records_available(void) 147edb47ec4SLluís { 14886946a2dSMichael Tokarev g_mutex_lock(&trace_lock); 149edb47ec4SLluís while (!(trace_available && trace_writeout_enabled)) { 15086946a2dSMichael Tokarev g_cond_signal(&trace_empty_cond); 15186946a2dSMichael Tokarev g_cond_wait(&trace_available_cond, &trace_lock); 152edb47ec4SLluís } 153edb47ec4SLluís trace_available = false; 15486946a2dSMichael Tokarev g_mutex_unlock(&trace_lock); 155edb47ec4SLluís } 156edb47ec4SLluís 15785aff158SStefan Hajnoczi static gpointer writeout_thread(gpointer opaque) 158edb47ec4SLluís { 15962bab732SHarsh Prateek Bora TraceRecord *recordptr; 16062bab732SHarsh Prateek Bora union { 16162bab732SHarsh Prateek Bora TraceRecord rec; 16262bab732SHarsh Prateek Bora uint8_t bytes[sizeof(TraceRecord) + sizeof(uint64_t)]; 16362bab732SHarsh Prateek Bora } dropped; 16462bab732SHarsh Prateek Bora unsigned int idx = 0; 165fb3a5085SMarkus Armbruster int dropped_count; 166edb47ec4SLluís size_t unused __attribute__ ((unused)); 167edb47ec4SLluís 168edb47ec4SLluís for (;;) { 169edb47ec4SLluís wait_for_trace_records_available(); 170edb47ec4SLluís 171e722d705SMarkus Armbruster if (g_atomic_int_get(&dropped_events)) { 17262bab732SHarsh Prateek Bora dropped.rec.event = DROPPED_EVENT_ID, 17362bab732SHarsh Prateek Bora dropped.rec.timestamp_ns = get_clock(); 174fb3a5085SMarkus Armbruster dropped.rec.length = sizeof(TraceRecord) + sizeof(uint64_t), 17526896cbfSStefan Hajnoczi dropped.rec.pid = trace_pid; 176b6b2c962SMarkus Armbruster do { 177e722d705SMarkus Armbruster dropped_count = g_atomic_int_get(&dropped_events); 178b6b2c962SMarkus Armbruster } while (!g_atomic_int_compare_and_exchange(&dropped_events, 179b6b2c962SMarkus Armbruster dropped_count, 0)); 180fb3a5085SMarkus Armbruster dropped.rec.arguments[0] = dropped_count; 18162bab732SHarsh Prateek Bora unused = fwrite(&dropped.rec, dropped.rec.length, 1, trace_fp); 182edb47ec4SLluís } 183edb47ec4SLluís 18462bab732SHarsh Prateek Bora while (get_trace_record(idx, &recordptr)) { 18562bab732SHarsh Prateek Bora unused = fwrite(recordptr, recordptr->length, 1, trace_fp); 18662bab732SHarsh Prateek Bora writeout_idx += recordptr->length; 18762bab732SHarsh Prateek Bora free(recordptr); /* dont use g_free, can deadlock when traced */ 188edb47ec4SLluís idx = writeout_idx % TRACE_BUF_LEN; 189edb47ec4SLluís } 190edb47ec4SLluís 191edb47ec4SLluís fflush(trace_fp); 192edb47ec4SLluís } 193edb47ec4SLluís return NULL; 194edb47ec4SLluís } 195edb47ec4SLluís 19662bab732SHarsh Prateek Bora void trace_record_write_u64(TraceBufferRecord *rec, uint64_t val) 197edb47ec4SLluís { 19862bab732SHarsh Prateek Bora rec->rec_off = write_to_buffer(rec->rec_off, &val, sizeof(uint64_t)); 199edb47ec4SLluís } 200edb47ec4SLluís 20162bab732SHarsh Prateek Bora void trace_record_write_str(TraceBufferRecord *rec, const char *s, uint32_t slen) 20262bab732SHarsh Prateek Bora { 20362bab732SHarsh Prateek Bora /* Write string length first */ 20462bab732SHarsh Prateek Bora rec->rec_off = write_to_buffer(rec->rec_off, &slen, sizeof(slen)); 20562bab732SHarsh Prateek Bora /* Write actual string now */ 20662bab732SHarsh Prateek Bora rec->rec_off = write_to_buffer(rec->rec_off, (void*)s, slen); 20762bab732SHarsh Prateek Bora } 208edb47ec4SLluís 20962bab732SHarsh Prateek Bora int trace_record_start(TraceBufferRecord *rec, TraceEventID event, size_t datasize) 21062bab732SHarsh Prateek Bora { 21162bab732SHarsh Prateek Bora unsigned int idx, rec_off, old_idx, new_idx; 21262bab732SHarsh Prateek Bora uint32_t rec_len = sizeof(TraceRecord) + datasize; 21360481e21SLluís Vilanova uint64_t event_u64 = event; 21462bab732SHarsh Prateek Bora uint64_t timestamp_ns = get_clock(); 21562bab732SHarsh Prateek Bora 216b6b2c962SMarkus Armbruster do { 217e722d705SMarkus Armbruster old_idx = g_atomic_int_get(&trace_idx); 21862bab732SHarsh Prateek Bora smp_rmb(); 21962bab732SHarsh Prateek Bora new_idx = old_idx + rec_len; 22062bab732SHarsh Prateek Bora 22162bab732SHarsh Prateek Bora if (new_idx - writeout_idx > TRACE_BUF_LEN) { 22262bab732SHarsh Prateek Bora /* Trace Buffer Full, Event dropped ! */ 223fb3a5085SMarkus Armbruster g_atomic_int_inc(&dropped_events); 22462bab732SHarsh Prateek Bora return -ENOSPC; 22562bab732SHarsh Prateek Bora } 226b6b2c962SMarkus Armbruster } while (!g_atomic_int_compare_and_exchange(&trace_idx, old_idx, new_idx)); 22762bab732SHarsh Prateek Bora 22862bab732SHarsh Prateek Bora idx = old_idx % TRACE_BUF_LEN; 22962bab732SHarsh Prateek Bora 23062bab732SHarsh Prateek Bora rec_off = idx; 23160481e21SLluís Vilanova rec_off = write_to_buffer(rec_off, &event_u64, sizeof(event_u64)); 23283d35d3eSHarsh Prateek Bora rec_off = write_to_buffer(rec_off, ×tamp_ns, sizeof(timestamp_ns)); 23383d35d3eSHarsh Prateek Bora rec_off = write_to_buffer(rec_off, &rec_len, sizeof(rec_len)); 23426896cbfSStefan Hajnoczi rec_off = write_to_buffer(rec_off, &trace_pid, sizeof(trace_pid)); 23562bab732SHarsh Prateek Bora 23662bab732SHarsh Prateek Bora rec->tbuf_idx = idx; 23762bab732SHarsh Prateek Bora rec->rec_off = (idx + sizeof(TraceRecord)) % TRACE_BUF_LEN; 23862bab732SHarsh Prateek Bora return 0; 23962bab732SHarsh Prateek Bora } 24062bab732SHarsh Prateek Bora 24162bab732SHarsh Prateek Bora static void read_from_buffer(unsigned int idx, void *dataptr, size_t size) 24262bab732SHarsh Prateek Bora { 24362bab732SHarsh Prateek Bora uint8_t *data_ptr = dataptr; 24462bab732SHarsh Prateek Bora uint32_t x = 0; 24562bab732SHarsh Prateek Bora while (x < size) { 24662bab732SHarsh Prateek Bora if (idx >= TRACE_BUF_LEN) { 24762bab732SHarsh Prateek Bora idx = idx % TRACE_BUF_LEN; 24862bab732SHarsh Prateek Bora } 24962bab732SHarsh Prateek Bora data_ptr[x++] = trace_buf[idx++]; 25062bab732SHarsh Prateek Bora } 25162bab732SHarsh Prateek Bora } 25262bab732SHarsh Prateek Bora 25362bab732SHarsh Prateek Bora static unsigned int write_to_buffer(unsigned int idx, void *dataptr, size_t size) 25462bab732SHarsh Prateek Bora { 25562bab732SHarsh Prateek Bora uint8_t *data_ptr = dataptr; 25662bab732SHarsh Prateek Bora uint32_t x = 0; 25762bab732SHarsh Prateek Bora while (x < size) { 25862bab732SHarsh Prateek Bora if (idx >= TRACE_BUF_LEN) { 25962bab732SHarsh Prateek Bora idx = idx % TRACE_BUF_LEN; 26062bab732SHarsh Prateek Bora } 26162bab732SHarsh Prateek Bora trace_buf[idx++] = data_ptr[x++]; 26262bab732SHarsh Prateek Bora } 26362bab732SHarsh Prateek Bora return idx; /* most callers wants to know where to write next */ 26462bab732SHarsh Prateek Bora } 26562bab732SHarsh Prateek Bora 26662bab732SHarsh Prateek Bora void trace_record_finish(TraceBufferRecord *rec) 26762bab732SHarsh Prateek Bora { 268db8894f2SHarsh Prateek Bora TraceRecord record; 269db8894f2SHarsh Prateek Bora read_from_buffer(rec->tbuf_idx, &record, sizeof(TraceRecord)); 27062bab732SHarsh Prateek Bora smp_wmb(); /* write barrier before marking as valid */ 271db8894f2SHarsh Prateek Bora record.event |= TRACE_RECORD_VALID; 272db8894f2SHarsh Prateek Bora write_to_buffer(rec->tbuf_idx, &record, sizeof(TraceRecord)); 27362bab732SHarsh Prateek Bora 27430d94087SStefan Hajnoczi if (((unsigned int)g_atomic_int_get(&trace_idx) - writeout_idx) 275e722d705SMarkus Armbruster > TRACE_BUF_FLUSH_THRESHOLD) { 276edb47ec4SLluís flush_trace_file(false); 277edb47ec4SLluís } 278edb47ec4SLluís } 279edb47ec4SLluís 280edb47ec4SLluís void st_set_trace_file_enabled(bool enable) 281edb47ec4SLluís { 282edb47ec4SLluís if (enable == !!trace_fp) { 283edb47ec4SLluís return; /* no change */ 284edb47ec4SLluís } 285edb47ec4SLluís 286edb47ec4SLluís /* Halt trace writeout */ 287edb47ec4SLluís flush_trace_file(true); 288edb47ec4SLluís trace_writeout_enabled = false; 289edb47ec4SLluís flush_trace_file(true); 290edb47ec4SLluís 291edb47ec4SLluís if (enable) { 2928ae601e8SHarsh Prateek Bora static const TraceLogHeader header = { 29362bab732SHarsh Prateek Bora .header_event_id = HEADER_EVENT_ID, 29462bab732SHarsh Prateek Bora .header_magic = HEADER_MAGIC, 29562bab732SHarsh Prateek Bora /* Older log readers will check for version at next location */ 29662bab732SHarsh Prateek Bora .header_version = HEADER_VERSION, 297edb47ec4SLluís }; 298edb47ec4SLluís 2996c2a4074SStefan Hajnoczi trace_fp = fopen(trace_file_name, "wb"); 300edb47ec4SLluís if (!trace_fp) { 301edb47ec4SLluís return; 302edb47ec4SLluís } 303edb47ec4SLluís 304edb47ec4SLluís if (fwrite(&header, sizeof header, 1, trace_fp) != 1) { 305edb47ec4SLluís fclose(trace_fp); 306edb47ec4SLluís trace_fp = NULL; 307edb47ec4SLluís return; 308edb47ec4SLluís } 309edb47ec4SLluís 310edb47ec4SLluís /* Resume trace writeout */ 311edb47ec4SLluís trace_writeout_enabled = true; 312edb47ec4SLluís flush_trace_file(false); 313edb47ec4SLluís } else { 314edb47ec4SLluís fclose(trace_fp); 315edb47ec4SLluís trace_fp = NULL; 316edb47ec4SLluís } 317edb47ec4SLluís } 318edb47ec4SLluís 319edb47ec4SLluís /** 320edb47ec4SLluís * Set the name of a trace file 321edb47ec4SLluís * 322edb47ec4SLluís * @file The trace file name or NULL for the default name-<pid> set at 323edb47ec4SLluís * config time 324edb47ec4SLluís */ 325edb47ec4SLluís bool st_set_trace_file(const char *file) 326edb47ec4SLluís { 327edb47ec4SLluís st_set_trace_file_enabled(false); 328edb47ec4SLluís 3294552e410SStefan Weil g_free(trace_file_name); 330edb47ec4SLluís 331edb47ec4SLluís if (!file) { 332*857a0e38SStefan Weil /* Type cast needed for Windows where getpid() returns an int. */ 333*857a0e38SStefan Weil trace_file_name = g_strdup_printf(CONFIG_TRACE_FILE, (pid_t)getpid()); 334edb47ec4SLluís } else { 3354552e410SStefan Weil trace_file_name = g_strdup_printf("%s", file); 336edb47ec4SLluís } 337edb47ec4SLluís 338edb47ec4SLluís st_set_trace_file_enabled(true); 339edb47ec4SLluís return true; 340edb47ec4SLluís } 341edb47ec4SLluís 342edb47ec4SLluís void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...)) 343edb47ec4SLluís { 344edb47ec4SLluís stream_printf(stream, "Trace file \"%s\" %s.\n", 345edb47ec4SLluís trace_file_name, trace_fp ? "on" : "off"); 346edb47ec4SLluís } 347edb47ec4SLluís 348fc764105SLluís void st_flush_trace_buffer(void) 349fc764105SLluís { 350fc764105SLluís flush_trace_file(true); 351fc764105SLluís } 352fc764105SLluís 35385aff158SStefan Hajnoczi /* Helper function to create a thread with signals blocked. Use glib's 35485aff158SStefan Hajnoczi * portable threads since QEMU abstractions cannot be used due to reentrancy in 35585aff158SStefan Hajnoczi * the tracer. Also note the signal masking on POSIX hosts so that the thread 35685aff158SStefan Hajnoczi * does not steal signals when the rest of the program wants them blocked. 35785aff158SStefan Hajnoczi */ 35885aff158SStefan Hajnoczi static GThread *trace_thread_create(GThreadFunc fn) 359edb47ec4SLluís { 36085aff158SStefan Hajnoczi GThread *thread; 36185aff158SStefan Hajnoczi #ifndef _WIN32 362edb47ec4SLluís sigset_t set, oldset; 363edb47ec4SLluís 364edb47ec4SLluís sigfillset(&set); 365edb47ec4SLluís pthread_sigmask(SIG_SETMASK, &set, &oldset); 36685aff158SStefan Hajnoczi #endif 3674a0e6714SStefan Hajnoczi 3684a0e6714SStefan Hajnoczi thread = g_thread_new("trace-thread", fn, NULL); 3694a0e6714SStefan Hajnoczi 37085aff158SStefan Hajnoczi #ifndef _WIN32 371edb47ec4SLluís pthread_sigmask(SIG_SETMASK, &oldset, NULL); 37285aff158SStefan Hajnoczi #endif 373edb47ec4SLluís 37485aff158SStefan Hajnoczi return thread; 37585aff158SStefan Hajnoczi } 37685aff158SStefan Hajnoczi 3775b808275SLluís Vilanova bool st_init(const char *file) 37885aff158SStefan Hajnoczi { 37985aff158SStefan Hajnoczi GThread *thread; 38085aff158SStefan Hajnoczi 38126896cbfSStefan Hajnoczi trace_pid = getpid(); 38226896cbfSStefan Hajnoczi 38385aff158SStefan Hajnoczi thread = trace_thread_create(writeout_thread); 38485aff158SStefan Hajnoczi if (!thread) { 385e4858974SLluís fprintf(stderr, "warning: unable to initialize simple trace backend\n"); 38685aff158SStefan Hajnoczi return false; 38785aff158SStefan Hajnoczi } 38885aff158SStefan Hajnoczi 389edb47ec4SLluís atexit(st_flush_trace_buffer); 390edb47ec4SLluís st_set_trace_file(file); 391edb47ec4SLluís return true; 392edb47ec4SLluís } 393