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