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 #include "qemu/option.h"
  14 #ifdef CONFIG_TRACE_SIMPLE
  15 #include "trace/simple.h"
  16 #endif
  17 #ifdef CONFIG_TRACE_FTRACE
  18 #include "trace/ftrace.h"
  19 #endif
  20 #ifdef CONFIG_TRACE_LOG
  21 #include "qemu/log.h"
  22 #endif
  23 #ifdef CONFIG_TRACE_SYSLOG
  24 #include <syslog.h>
  25 #endif
  26 #include "qapi/error.h"
  27 #include "qemu/error-report.h"
  28 #include "qemu/config-file.h"
  29 #include "monitor/monitor.h"
  30 #include "trace-root.h"
  31
  32 int trace_events_enabled_count;
  33
  34 typedef struct TraceEventGroup {
  35     TraceEvent **events;
  36 } TraceEventGroup;
  37
  38 static TraceEventGroup *event_groups;
  39 static size_t nevent_groups;
  40 static uint32_t next_id;
  41 static uint32_t next_vcpu_id;
  42
  43 QemuOptsList qemu_trace_opts = {
  44     .name = "trace",
  45     .implied_opt_name = "enable",
  46     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
  47     .desc = {
  48         {
  49             .name = "enable",
  50             .type = QEMU_OPT_STRING,
  51         },
  52         {
  53             .name = "events",
  54             .type = QEMU_OPT_STRING,
  55         },{
  56             .name = "file",
  57             .type = QEMU_OPT_STRING,
  58         },
  59         { /* end of list */ }
  60     },
  61 };
  62
  63
  64 void trace_event_register_group(TraceEvent **events)
  65 {
  66     size_t i;
  67     for (i = 0; events[i] != NULL; i++) {
  68         events[i]->id = next_id++;
  69         if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) {
  70             continue;
  71         }
  72
  73         if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) {
  74             events[i]->vcpu_id = next_vcpu_id++;
  75         } else {
  76             warn_report("too many vcpu trace events; dropping '%s'",
  77                         events[i]->name);
  78         }
  79     }
  80     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
  81     event_groups[nevent_groups].events = events;
  82     nevent_groups++;
  83 }
  84
  85
  86 TraceEvent *trace_event_name(const char *name)
  87 {
  88     assert(name != NULL);
  89
  90     TraceEventIter iter;
  91     TraceEvent *ev;
  92     trace_event_iter_init(&iter, NULL);
  93     while ((ev = trace_event_iter_next(&iter)) != NULL) {
  94         if (strcmp(trace_event_get_name(ev), name) == 0) {
  95             return ev;
  96         }
  97     }
  98     return NULL;
  99 }
 100
 101 static bool pattern_glob(const char *pat, const char *ev)
 102 {
 103     while (*pat != '\0' && *ev != '\0') {
 104         if (*pat == *ev) {
 105             pat++;
 106             ev++;
 107         }
 108         else if (*pat == '*') {
 109             if (pattern_glob(pat, ev+1)) {
 110                 return true;
 111             } else if (pattern_glob(pat+1, ev)) {
 112                 return true;
 113             } else {
 114                 return false;
 115             }
 116         } else {
 117             return false;
 118         }
 119     }
 120
 121     while (*pat == '*') {
 122         pat++;
 123     }
 124
 125     if (*pat == '\0' && *ev == '\0') {
 126         return true;
 127     } else {
 128         return false;
 129     }
 130 }
 131
 132
 133 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
 134 {
 135     iter->event = 0;
 136     iter->group = 0;
 137     iter->pattern = pattern;
 138 }
 139
 140 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
 141 {
 142     while (iter->group < nevent_groups &&
 143            event_groups[iter->group].events[iter->event] != NULL) {
 144         TraceEvent *ev = event_groups[iter->group].events[iter->event];
 145         iter->event++;
 146         if (event_groups[iter->group].events[iter->event] == NULL) {
 147             iter->event = 0;
 148             iter->group++;
 149         }
 150         if (!iter->pattern ||
 151             pattern_glob(iter->pattern,
 152                          trace_event_get_name(ev))) {
 153             return ev;
 154         }
 155     }
 156
 157     return NULL;
 158 }
 159
 160 void trace_list_events(void)
 161 {
 162     TraceEventIter iter;
 163     TraceEvent *ev;
 164     trace_event_iter_init(&iter, NULL);
 165     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 166         fprintf(stderr, "%s\n", trace_event_get_name(ev));
 167     }
 168 #ifdef CONFIG_TRACE_DTRACE
 169     fprintf(stderr, "This list of names of trace points may be incomplete "
 170                     "when using the DTrace/SystemTap backends.\n"
 171                     "Run 'qemu-trace-stap list %s' to print the full list.\n",
 172             error_get_progname());
 173 #endif
 174 }
 175
 176 static void do_trace_enable_events(const char *line_buf)
 177 {
 178     const bool enable = ('-' != line_buf[0]);
 179     const char *line_ptr = enable ? line_buf : line_buf + 1;
 180     TraceEventIter iter;
 181     TraceEvent *ev;
 182     bool is_pattern = trace_event_is_pattern(line_ptr);
 183
 184     trace_event_iter_init(&iter, line_ptr);
 185     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 186         if (!trace_event_get_state_static(ev)) {
 187             if (!is_pattern) {
 188                 warn_report("trace event '%s' is not traceable",
 189                             line_ptr);
 190                 return;
 191             }
 192             continue;
 193         }
 194
 195         /* start tracing */
 196         trace_event_set_state_dynamic(ev, enable);
 197         if (!is_pattern) {
 198             return;
 199         }
 200     }
 201
 202     if (!is_pattern) {
 203         warn_report("trace event '%s' does not exist",
 204                     line_ptr);
 205     }
 206 }
 207
 208 void trace_enable_events(const char *line_buf)
 209 {
 210     if (is_help_option(line_buf)) {
 211         trace_list_events();
 212         if (cur_mon == NULL) {
 213             exit(0);
 214         }
 215     } else {
 216         do_trace_enable_events(line_buf);
 217     }
 218 }
 219
 220 static void trace_init_events(const char *fname)
 221 {
 222     Location loc;
 223     FILE *fp;
 224     char line_buf[1024];
 225     size_t line_idx = 0;
 226
 227     if (fname == NULL) {
 228         return;
 229     }
 230
 231     loc_push_none(&loc);
 232     loc_set_file(fname, 0);
 233     fp = fopen(fname, "r");
 234     if (!fp) {
 235         error_report("%s", strerror(errno));
 236         exit(1);
 237     }
 238     while (fgets(line_buf, sizeof(line_buf), fp)) {
 239         loc_set_file(fname, ++line_idx);
 240         size_t len = strlen(line_buf);
 241         if (len > 1) {              /* skip empty lines */
 242             line_buf[len - 1] = '\0';
 243             if ('#' == line_buf[0]) { /* skip commented lines */
 244                 continue;
 245             }
 246             trace_enable_events(line_buf);
 247         }
 248     }
 249     if (fclose(fp) != 0) {
 250         loc_set_file(fname, 0);
 251         error_report("%s", strerror(errno));
 252         exit(1);
 253     }
 254     loc_pop(&loc);
 255 }
 256
 257 void trace_init_file(const char *file)
 258 {
 259 #ifdef CONFIG_TRACE_SIMPLE
 260     st_set_trace_file(file);
 261 #elif defined CONFIG_TRACE_LOG
 262     /* If both the simple and the log backends are enabled, "--trace file"
 263      * only applies to the simple backend; use "-D" for the log backend.
 264      */
 265     if (file) {
 266         qemu_set_log_filename(file, &error_fatal);
 267     }
 268 #else
 269     if (file) {
 270         fprintf(stderr, "error: --trace file=...: "
 271                 "option not supported by the selected tracing backends\n");
 272         exit(1);
 273     }
 274 #endif
 275 }
 276
 277 void trace_fini_vcpu(CPUState *vcpu)
 278 {
 279     TraceEventIter iter;
 280     TraceEvent *ev;
 281
 282     trace_guest_cpu_exit(vcpu);
 283
 284     trace_event_iter_init(&iter, NULL);
 285     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 286         if (trace_event_is_vcpu(ev) &&
 287             trace_event_get_state_static(ev) &&
 288             trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
 289             /* must disable to affect the global counter */
 290             trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
 291         }
 292     }
 293 }
 294
 295 bool trace_init_backends(void)
 296 {
 297 #ifdef CONFIG_TRACE_SIMPLE
 298     if (!st_init()) {
 299         fprintf(stderr, "failed to initialize simple tracing backend.\n");
 300         return false;
 301     }
 302 #endif
 303
 304 #ifdef CONFIG_TRACE_FTRACE
 305     if (!ftrace_init()) {
 306         fprintf(stderr, "failed to initialize ftrace backend.\n");
 307         return false;
 308     }
 309 #endif
 310
 311 #ifdef CONFIG_TRACE_SYSLOG
 312     openlog(NULL, LOG_PID, LOG_DAEMON);
 313 #endif
 314
 315     return true;
 316 }
 317
 318 char *trace_opt_parse(const char *optarg)
 319 {
 320     char *trace_file;
 321     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
 322                                              optarg, true);
 323     if (!opts) {
 324         exit(1);
 325     }
 326     if (qemu_opt_get(opts, "enable")) {
 327         trace_enable_events(qemu_opt_get(opts, "enable"));
 328     }
 329     trace_init_events(qemu_opt_get(opts, "events"));
 330     trace_file = g_strdup(qemu_opt_get(opts, "file"));
 331     qemu_opts_del(opts);
 332
 333     return trace_file;
 334 }
 335
 336 uint32_t trace_get_vcpu_event_count(void)
 337 {
 338     return next_vcpu_id;
 339 }