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  * Interpretation depends on wether the event has the 'vcpu' property:
  33  * - false: Boolean value indicating whether the event is active.
  34  * - true : Integral counting the number of vCPUs that have this event enabled.
  35  */
  36 uint16_t trace_events_dstate[TRACE_EVENT_COUNT];
  37
  38 QemuOptsList qemu_trace_opts = {
  39     .name = "trace",
  40     .implied_opt_name = "enable",
  41     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
  42     .desc = {
  43         {
  44             .name = "enable",
  45             .type = QEMU_OPT_STRING,
  46         },
  47         {
  48             .name = "events",
  49             .type = QEMU_OPT_STRING,
  50         },{
  51             .name = "file",
  52             .type = QEMU_OPT_STRING,
  53         },
  54         { /* end of list */ }
  55     },
  56 };
  57
  58
  59 TraceEvent *trace_event_name(const char *name)
  60 {
  61     assert(name != NULL);
  62
  63     TraceEventID i;
  64     for (i = 0; i < trace_event_count(); i++) {
  65         TraceEvent *ev = trace_event_id(i);
  66         if (strcmp(trace_event_get_name(ev), name) == 0) {
  67             return ev;
  68         }
  69     }
  70     return NULL;
  71 }
  72
  73 static bool pattern_glob(const char *pat, const char *ev)
  74 {
  75     while (*pat != '\0' && *ev != '\0') {
  76         if (*pat == *ev) {
  77             pat++;
  78             ev++;
  79         }
  80         else if (*pat == '*') {
  81             if (pattern_glob(pat, ev+1)) {
  82                 return true;
  83             } else if (pattern_glob(pat+1, ev)) {
  84                 return true;
  85             } else {
  86                 return false;
  87             }
  88         } else {
  89             return false;
  90         }
  91     }
  92
  93     while (*pat == '*') {
  94         pat++;
  95     }
  96
  97     if (*pat == '\0' && *ev == '\0') {
  98         return true;
  99     } else {
 100         return false;
 101     }
 102 }
 103
 104 TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
 105 {
 106     assert(pat != NULL);
 107
 108     TraceEventID i;
 109
 110     if (ev == NULL) {
 111         i = -1;
 112     } else {
 113         i = trace_event_get_id(ev);
 114     }
 115     i++;
 116
 117     while (i < trace_event_count()) {
 118         TraceEvent *res = trace_event_id(i);
 119         if (pattern_glob(pat, trace_event_get_name(res))) {
 120             return res;
 121         }
 122         i++;
 123     }
 124
 125     return NULL;
 126 }
 127
 128 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
 129 {
 130     iter->event = 0;
 131     iter->pattern = pattern;
 132 }
 133
 134 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
 135 {
 136     while (iter->event < TRACE_EVENT_COUNT) {
 137         TraceEvent *ev = &(trace_events[iter->event]);
 138         iter->event++;
 139         if (!iter->pattern ||
 140             pattern_glob(iter->pattern,
 141                          trace_event_get_name(ev))) {
 142             return ev;
 143         }
 144     }
 145
 146     return NULL;
 147 }
 148
 149 void trace_list_events(void)
 150 {
 151     int i;
 152     for (i = 0; i < trace_event_count(); i++) {
 153         TraceEvent *res = trace_event_id(i);
 154         fprintf(stderr, "%s\n", trace_event_get_name(res));
 155     }
 156 }
 157
 158 static void do_trace_enable_events(const char *line_buf)
 159 {
 160     const bool enable = ('-' != line_buf[0]);
 161     const char *line_ptr = enable ? line_buf : line_buf + 1;
 162
 163     if (trace_event_is_pattern(line_ptr)) {
 164         TraceEvent *ev = NULL;
 165         while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
 166             if (trace_event_get_state_static(ev)) {
 167                 trace_event_set_state_dynamic_init(ev, enable);
 168             }
 169         }
 170     } else {
 171         TraceEvent *ev = trace_event_name(line_ptr);
 172         if (ev == NULL) {
 173             error_report("WARNING: trace event '%s' does not exist",
 174                          line_ptr);
 175         } else if (!trace_event_get_state_static(ev)) {
 176             error_report("WARNING: trace event '%s' is not traceable",
 177                          line_ptr);
 178         } else {
 179             trace_event_set_state_dynamic_init(ev, enable);
 180         }
 181     }
 182 }
 183
 184 void trace_enable_events(const char *line_buf)
 185 {
 186     if (is_help_option(line_buf)) {
 187         trace_list_events();
 188         if (cur_mon == NULL) {
 189             exit(0);
 190         }
 191     } else {
 192         do_trace_enable_events(line_buf);
 193     }
 194 }
 195
 196 static void trace_init_events(const char *fname)
 197 {
 198     Location loc;
 199     FILE *fp;
 200     char line_buf[1024];
 201     size_t line_idx = 0;
 202
 203     if (fname == NULL) {
 204         return;
 205     }
 206
 207     loc_push_none(&loc);
 208     loc_set_file(fname, 0);
 209     fp = fopen(fname, "r");
 210     if (!fp) {
 211         error_report("%s", strerror(errno));
 212         exit(1);
 213     }
 214     while (fgets(line_buf, sizeof(line_buf), fp)) {
 215         loc_set_file(fname, ++line_idx);
 216         size_t len = strlen(line_buf);
 217         if (len > 1) {              /* skip empty lines */
 218             line_buf[len - 1] = '\0';
 219             if ('#' == line_buf[0]) { /* skip commented lines */
 220                 continue;
 221             }
 222             trace_enable_events(line_buf);
 223         }
 224     }
 225     if (fclose(fp) != 0) {
 226         loc_set_file(fname, 0);
 227         error_report("%s", strerror(errno));
 228         exit(1);
 229     }
 230     loc_pop(&loc);
 231 }
 232
 233 void trace_init_file(const char *file)
 234 {
 235 #ifdef CONFIG_TRACE_SIMPLE
 236     st_set_trace_file(file);
 237 #elif defined CONFIG_TRACE_LOG
 238     /* If both the simple and the log backends are enabled, "-trace file"
 239      * only applies to the simple backend; use "-D" for the log backend.
 240      */
 241     if (file) {
 242         qemu_set_log_filename(file, &error_fatal);
 243     }
 244 #else
 245     if (file) {
 246         fprintf(stderr, "error: -trace file=...: "
 247                 "option not supported by the selected tracing backends\n");
 248         exit(1);
 249     }
 250 #endif
 251 }
 252
 253 bool trace_init_backends(void)
 254 {
 255 #ifdef CONFIG_TRACE_SIMPLE
 256     if (!st_init()) {
 257         fprintf(stderr, "failed to initialize simple tracing backend.\n");
 258         return false;
 259     }
 260 #endif
 261
 262 #ifdef CONFIG_TRACE_FTRACE
 263     if (!ftrace_init()) {
 264         fprintf(stderr, "failed to initialize ftrace backend.\n");
 265         return false;
 266     }
 267 #endif
 268
 269 #ifdef CONFIG_TRACE_SYSLOG
 270     openlog(NULL, LOG_PID, LOG_DAEMON);
 271 #endif
 272
 273     return true;
 274 }
 275
 276 char *trace_opt_parse(const char *optarg)
 277 {
 278     char *trace_file;
 279     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
 280                                              optarg, true);
 281     if (!opts) {
 282         exit(1);
 283     }
 284     if (qemu_opt_get(opts, "enable")) {
 285         trace_enable_events(qemu_opt_get(opts, "enable"));
 286     }
 287     trace_init_events(qemu_opt_get(opts, "events"));
 288     trace_file = g_strdup(qemu_opt_get(opts, "file"));
 289     qemu_opts_del(opts);
 290
 291     return trace_file;
 292 }