trace/control.c

   1 /*
   2  * Interface for configuring and controlling the state of tracing events.
   3  *
   4  * Copyright (C) 2011-2016 Lluís Vilanova <vilanova@ac.upc.edu>
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  */
   9
  10 #include "qemu/osdep.h"
  11 #include "trace/control.h"
  12 #include "qemu/help_option.h"
  13 #ifdef CONFIG_TRACE_SIMPLE
  14 #include "trace/simple.h"
  15 #endif
  16 #ifdef CONFIG_TRACE_FTRACE
  17 #include "trace/ftrace.h"
  18 #endif
  19 #ifdef CONFIG_TRACE_LOG
  20 #include "qemu/log.h"
  21 #endif
  22 #ifdef CONFIG_TRACE_SYSLOG
  23 #include <syslog.h>
  24 #endif
  25 #include "qapi/error.h"
  26 #include "qemu/error-report.h"
  27 #include "qemu/config-file.h"
  28 #include "monitor/monitor.h"
  29 #include "trace-root.h"
  30
  31 int trace_events_enabled_count;
  32
  33 typedef struct TraceEventGroup {
  34     TraceEvent **events;
  35 } TraceEventGroup;
  36
  37 static TraceEventGroup *event_groups;
  38 static size_t nevent_groups;
  39 static uint32_t next_id;
  40 static uint32_t next_vcpu_id;
  41
  42 QemuOptsList qemu_trace_opts = {
  43     .name = "trace",
  44     .implied_opt_name = "enable",
  45     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
  46     .desc = {
  47         {
  48             .name = "enable",
  49             .type = QEMU_OPT_STRING,
  50         },
  51         {
  52             .name = "events",
  53             .type = QEMU_OPT_STRING,
  54         },{
  55             .name = "file",
  56             .type = QEMU_OPT_STRING,
  57         },
  58         { /* end of list */ }
  59     },
  60 };
  61
  62
  63 void trace_event_register_group(TraceEvent **events)
  64 {
  65     size_t i;
  66     for (i = 0; events[i] != NULL; i++) {
  67         events[i]->id = next_id++;
  68         if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) {
  69             continue;
  70         }
  71
  72         if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) {
  73             events[i]->vcpu_id = next_vcpu_id++;
  74         } else {
  75             error_report("WARNING: too many vcpu trace events; dropping '%s'",
  76                          events[i]->name);
  77         }
  78     }
  79     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
  80     event_groups[nevent_groups].events = events;
  81     nevent_groups++;
  82 }
  83
  84
  85 TraceEvent *trace_event_name(const char *name)
  86 {
  87     assert(name != NULL);
  88
  89     TraceEventIter iter;
  90     TraceEvent *ev;
  91     trace_event_iter_init(&iter, NULL);
  92     while ((ev = trace_event_iter_next(&iter)) != NULL) {
  93         if (strcmp(trace_event_get_name(ev), name) == 0) {
  94             return ev;
  95         }
  96     }
  97     return NULL;
  98 }
  99
 100 static bool pattern_glob(const char *pat, const char *ev)
 101 {
 102     while (*pat != '\0' && *ev != '\0') {
 103         if (*pat == *ev) {
 104             pat++;
 105             ev++;
 106         }
 107         else if (*pat == '*') {
 108             if (pattern_glob(pat, ev+1)) {
 109                 return true;
 110             } else if (pattern_glob(pat+1, ev)) {
 111                 return true;
 112             } else {
 113                 return false;
 114             }
 115         } else {
 116             return false;
 117         }
 118     }
 119
 120     while (*pat == '*') {
 121         pat++;
 122     }
 123
 124     if (*pat == '\0' && *ev == '\0') {
 125         return true;
 126     } else {
 127         return false;
 128     }
 129 }
 130
 131
 132 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
 133 {
 134     iter->event = 0;
 135     iter->group = 0;
 136     iter->pattern = pattern;
 137 }
 138
 139 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
 140 {
 141     while (iter->group < nevent_groups &&
 142            event_groups[iter->group].events[iter->event] != NULL) {
 143         TraceEvent *ev = event_groups[iter->group].events[iter->event];
 144         iter->event++;
 145         if (event_groups[iter->group].events[iter->event] == NULL) {
 146             iter->event = 0;
 147             iter->group++;
 148         }
 149         if (!iter->pattern ||
 150             pattern_glob(iter->pattern,
 151                          trace_event_get_name(ev))) {
 152             return ev;
 153         }
 154     }
 155
 156     return NULL;
 157 }
 158
 159 void trace_list_events(void)
 160 {
 161     TraceEventIter iter;
 162     TraceEvent *ev;
 163     trace_event_iter_init(&iter, NULL);
 164     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 165         fprintf(stderr, "%s\n", trace_event_get_name(ev));
 166     }
 167 }
 168
 169 static void do_trace_enable_events(const char *line_buf)
 170 {
 171     const bool enable = ('-' != line_buf[0]);
 172     const char *line_ptr = enable ? line_buf : line_buf + 1;
 173     TraceEventIter iter;
 174     TraceEvent *ev;
 175     bool is_pattern = trace_event_is_pattern(line_ptr);
 176
 177     trace_event_iter_init(&iter, line_ptr);
 178     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 179         if (!trace_event_get_state_static(ev)) {
 180             if (!is_pattern) {
 181                 warn_report("trace event '%s' is not traceable",
 182                             line_ptr);
 183                 return;
 184             }
 185             continue;
 186         }
 187
 188         /* start tracing */
 189         trace_event_set_state_dynamic(ev, enable);
 190         if (!is_pattern) {
 191             return;
 192         }
 193     }
 194
 195     if (!is_pattern) {
 196         warn_report("trace event '%s' does not exist",
 197                     line_ptr);
 198     }
 199 }
 200
 201 void trace_enable_events(const char *line_buf)
 202 {
 203     if (is_help_option(line_buf)) {
 204         trace_list_events();
 205         if (cur_mon == NULL) {
 206             exit(0);
 207         }
 208     } else {
 209         do_trace_enable_events(line_buf);
 210     }
 211 }
 212
 213 static void trace_init_events(const char *fname)
 214 {
 215     Location loc;
 216     FILE *fp;
 217     char line_buf[1024];
 218     size_t line_idx = 0;
 219
 220     if (fname == NULL) {
 221         return;
 222     }
 223
 224     loc_push_none(&loc);
 225     loc_set_file(fname, 0);
 226     fp = fopen(fname, "r");
 227     if (!fp) {
 228         error_report("%s", strerror(errno));
 229         exit(1);
 230     }
 231     while (fgets(line_buf, sizeof(line_buf), fp)) {
 232         loc_set_file(fname, ++line_idx);
 233         size_t len = strlen(line_buf);
 234         if (len > 1) {              /* skip empty lines */
 235             line_buf[len - 1] = '\0';
 236             if ('#' == line_buf[0]) { /* skip commented lines */
 237                 continue;
 238             }
 239             trace_enable_events(line_buf);
 240         }
 241     }
 242     if (fclose(fp) != 0) {
 243         loc_set_file(fname, 0);
 244         error_report("%s", strerror(errno));
 245         exit(1);
 246     }
 247     loc_pop(&loc);
 248 }
 249
 250 void trace_init_file(const char *file)
 251 {
 252 #ifdef CONFIG_TRACE_SIMPLE
 253     st_set_trace_file(file);
 254 #elif defined CONFIG_TRACE_LOG
 255     /* If both the simple and the log backends are enabled, "-trace file"
 256      * only applies to the simple backend; use "-D" for the log backend.
 257      */
 258     if (file) {
 259         qemu_set_log_filename(file, &error_fatal);
 260     }
 261 #else
 262     if (file) {
 263         fprintf(stderr, "error: -trace file=...: "
 264                 "option not supported by the selected tracing backends\n");
 265         exit(1);
 266     }
 267 #endif
 268 }
 269
 270 void trace_fini_vcpu(CPUState *vcpu)
 271 {
 272     TraceEventIter iter;
 273     TraceEvent *ev;
 274
 275     trace_guest_cpu_exit(vcpu);
 276
 277     trace_event_iter_init(&iter, NULL);
 278     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 279         if (trace_event_is_vcpu(ev) &&
 280             trace_event_get_state_static(ev) &&
 281             trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
 282             /* must disable to affect the global counter */
 283             trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
 284         }
 285     }
 286 }
 287
 288 bool trace_init_backends(void)
 289 {
 290 #ifdef CONFIG_TRACE_SIMPLE
 291     if (!st_init()) {
 292         fprintf(stderr, "failed to initialize simple tracing backend.\n");
 293         return false;
 294     }
 295 #endif
 296
 297 #ifdef CONFIG_TRACE_FTRACE
 298     if (!ftrace_init()) {
 299         fprintf(stderr, "failed to initialize ftrace backend.\n");
 300         return false;
 301     }
 302 #endif
 303
 304 #ifdef CONFIG_TRACE_SYSLOG
 305     openlog(NULL, LOG_PID, LOG_DAEMON);
 306 #endif
 307
 308     return true;
 309 }
 310
 311 char *trace_opt_parse(const char *optarg)
 312 {
 313     char *trace_file;
 314     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
 315                                              optarg, true);
 316     if (!opts) {
 317         exit(1);
 318     }
 319     if (qemu_opt_get(opts, "enable")) {
 320         trace_enable_events(qemu_opt_get(opts, "enable"));
 321     }
 322     trace_init_events(qemu_opt_get(opts, "events"));
 323     trace_file = g_strdup(qemu_opt_get(opts, "file"));
 324     qemu_opts_del(opts);
 325
 326     return trace_file;
 327 }
 328
 329 uint32_t trace_get_vcpu_event_count(void)
 330 {
 331     return next_vcpu_id;
 332 }