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.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             events[i]->vcpu_id = next_vcpu_id++;
  70         }
  71     }
  72     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
  73     event_groups[nevent_groups].events = events;
  74     nevent_groups++;
  75 }
  76
  77
  78 TraceEvent *trace_event_name(const char *name)
  79 {
  80     assert(name != NULL);
  81
  82     TraceEventIter iter;
  83     TraceEvent *ev;
  84     trace_event_iter_init(&iter, NULL);
  85     while ((ev = trace_event_iter_next(&iter)) != NULL) {
  86         if (strcmp(trace_event_get_name(ev), name) == 0) {
  87             return ev;
  88         }
  89     }
  90     return NULL;
  91 }
  92
  93 static bool pattern_glob(const char *pat, const char *ev)
  94 {
  95     while (*pat != '\0' && *ev != '\0') {
  96         if (*pat == *ev) {
  97             pat++;
  98             ev++;
  99         }
 100         else if (*pat == '*') {
 101             if (pattern_glob(pat, ev+1)) {
 102                 return true;
 103             } else if (pattern_glob(pat+1, ev)) {
 104                 return true;
 105             } else {
 106                 return false;
 107             }
 108         } else {
 109             return false;
 110         }
 111     }
 112
 113     while (*pat == '*') {
 114         pat++;
 115     }
 116
 117     if (*pat == '\0' && *ev == '\0') {
 118         return true;
 119     } else {
 120         return false;
 121     }
 122 }
 123
 124
 125 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
 126 {
 127     iter->event = 0;
 128     iter->group = 0;
 129     iter->pattern = pattern;
 130 }
 131
 132 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
 133 {
 134     while (iter->group < nevent_groups &&
 135            event_groups[iter->group].events[iter->event] != NULL) {
 136         TraceEvent *ev = event_groups[iter->group].events[iter->event];
 137         iter->event++;
 138         if (event_groups[iter->group].events[iter->event] == NULL) {
 139             iter->event = 0;
 140             iter->group++;
 141         }
 142         if (!iter->pattern ||
 143             pattern_glob(iter->pattern,
 144                          trace_event_get_name(ev))) {
 145             return ev;
 146         }
 147     }
 148
 149     return NULL;
 150 }
 151
 152 void trace_list_events(void)
 153 {
 154     TraceEventIter iter;
 155     TraceEvent *ev;
 156     trace_event_iter_init(&iter, NULL);
 157     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 158         fprintf(stderr, "%s\n", trace_event_get_name(ev));
 159     }
 160 }
 161
 162 static void do_trace_enable_events(const char *line_buf)
 163 {
 164     const bool enable = ('-' != line_buf[0]);
 165     const char *line_ptr = enable ? line_buf : line_buf + 1;
 166     TraceEventIter iter;
 167     TraceEvent *ev;
 168     bool is_pattern = trace_event_is_pattern(line_ptr);
 169
 170     trace_event_iter_init(&iter, line_ptr);
 171     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 172         if (!trace_event_get_state_static(ev)) {
 173             if (!is_pattern) {
 174                 error_report("WARNING: trace event '%s' is not traceable",
 175                              line_ptr);
 176                 return;
 177             }
 178             continue;
 179         }
 180
 181         /* start tracing */
 182         trace_event_set_state_dynamic(ev, enable);
 183         if (!is_pattern) {
 184             return;
 185         }
 186     }
 187
 188     if (!is_pattern) {
 189         error_report("WARNING: trace event '%s' does not exist",
 190                      line_ptr);
 191     }
 192 }
 193
 194 void trace_enable_events(const char *line_buf)
 195 {
 196     if (is_help_option(line_buf)) {
 197         trace_list_events();
 198         if (cur_mon == NULL) {
 199             exit(0);
 200         }
 201     } else {
 202         do_trace_enable_events(line_buf);
 203     }
 204 }
 205
 206 static void trace_init_events(const char *fname)
 207 {
 208     Location loc;
 209     FILE *fp;
 210     char line_buf[1024];
 211     size_t line_idx = 0;
 212
 213     if (fname == NULL) {
 214         return;
 215     }
 216
 217     loc_push_none(&loc);
 218     loc_set_file(fname, 0);
 219     fp = fopen(fname, "r");
 220     if (!fp) {
 221         error_report("%s", strerror(errno));
 222         exit(1);
 223     }
 224     while (fgets(line_buf, sizeof(line_buf), fp)) {
 225         loc_set_file(fname, ++line_idx);
 226         size_t len = strlen(line_buf);
 227         if (len > 1) {              /* skip empty lines */
 228             line_buf[len - 1] = '\0';
 229             if ('#' == line_buf[0]) { /* skip commented lines */
 230                 continue;
 231             }
 232             trace_enable_events(line_buf);
 233         }
 234     }
 235     if (fclose(fp) != 0) {
 236         loc_set_file(fname, 0);
 237         error_report("%s", strerror(errno));
 238         exit(1);
 239     }
 240     loc_pop(&loc);
 241 }
 242
 243 void trace_init_file(const char *file)
 244 {
 245 #ifdef CONFIG_TRACE_SIMPLE
 246     st_set_trace_file(file);
 247 #elif defined CONFIG_TRACE_LOG
 248     /* If both the simple and the log backends are enabled, "-trace file"
 249      * only applies to the simple backend; use "-D" for the log backend.
 250      */
 251     if (file) {
 252         qemu_set_log_filename(file, &error_fatal);
 253     }
 254 #else
 255     if (file) {
 256         fprintf(stderr, "error: -trace file=...: "
 257                 "option not supported by the selected tracing backends\n");
 258         exit(1);
 259     }
 260 #endif
 261 }
 262
 263 void trace_fini_vcpu(CPUState *vcpu)
 264 {
 265     TraceEventIter iter;
 266     TraceEvent *ev;
 267
 268     trace_guest_cpu_exit(vcpu);
 269
 270     trace_event_iter_init(&iter, NULL);
 271     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 272         if (trace_event_is_vcpu(ev) &&
 273             trace_event_get_state_static(ev) &&
 274             trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
 275             /* must disable to affect the global counter */
 276             trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
 277         }
 278     }
 279 }
 280
 281 bool trace_init_backends(void)
 282 {
 283 #ifdef CONFIG_TRACE_SIMPLE
 284     if (!st_init()) {
 285         fprintf(stderr, "failed to initialize simple tracing backend.\n");
 286         return false;
 287     }
 288 #endif
 289
 290 #ifdef CONFIG_TRACE_FTRACE
 291     if (!ftrace_init()) {
 292         fprintf(stderr, "failed to initialize ftrace backend.\n");
 293         return false;
 294     }
 295 #endif
 296
 297 #ifdef CONFIG_TRACE_SYSLOG
 298     openlog(NULL, LOG_PID, LOG_DAEMON);
 299 #endif
 300
 301     return true;
 302 }
 303
 304 char *trace_opt_parse(const char *optarg)
 305 {
 306     char *trace_file;
 307     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
 308                                              optarg, true);
 309     if (!opts) {
 310         exit(1);
 311     }
 312     if (qemu_opt_get(opts, "enable")) {
 313         trace_enable_events(qemu_opt_get(opts, "enable"));
 314     }
 315     trace_init_events(qemu_opt_get(opts, "events"));
 316     trace_file = g_strdup(qemu_opt_get(opts, "file"));
 317     qemu_opts_del(opts);
 318
 319     return trace_file;
 320 }
 321
 322 uint32_t trace_get_vcpu_event_count(void)
 323 {
 324     return next_vcpu_id;
 325 }