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
  39 QemuOptsList qemu_trace_opts = {
  40     .name = "trace",
  41     .implied_opt_name = "enable",
  42     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
  43     .desc = {
  44         {
  45             .name = "enable",
  46             .type = QEMU_OPT_STRING,
  47         },
  48         {
  49             .name = "events",
  50             .type = QEMU_OPT_STRING,
  51         },{
  52             .name = "file",
  53             .type = QEMU_OPT_STRING,
  54         },
  55         { /* end of list */ }
  56     },
  57 };
  58
  59
  60 void trace_event_register_group(TraceEvent **events)
  61 {
  62     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
  63     event_groups[nevent_groups].events = events;
  64     nevent_groups++;
  65 }
  66
  67
  68 TraceEvent *trace_event_name(const char *name)
  69 {
  70     assert(name != NULL);
  71
  72     TraceEventIter iter;
  73     TraceEvent *ev;
  74     trace_event_iter_init(&iter, NULL);
  75     while ((ev = trace_event_iter_next(&iter)) != NULL) {
  76         if (strcmp(trace_event_get_name(ev), name) == 0) {
  77             return ev;
  78         }
  79     }
  80     return NULL;
  81 }
  82
  83 static bool pattern_glob(const char *pat, const char *ev)
  84 {
  85     while (*pat != '\0' && *ev != '\0') {
  86         if (*pat == *ev) {
  87             pat++;
  88             ev++;
  89         }
  90         else if (*pat == '*') {
  91             if (pattern_glob(pat, ev+1)) {
  92                 return true;
  93             } else if (pattern_glob(pat+1, ev)) {
  94                 return true;
  95             } else {
  96                 return false;
  97             }
  98         } else {
  99             return false;
 100         }
 101     }
 102
 103     while (*pat == '*') {
 104         pat++;
 105     }
 106
 107     if (*pat == '\0' && *ev == '\0') {
 108         return true;
 109     } else {
 110         return false;
 111     }
 112 }
 113
 114
 115 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
 116 {
 117     iter->event = 0;
 118     iter->group = 0;
 119     iter->pattern = pattern;
 120 }
 121
 122 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
 123 {
 124     while (iter->group < nevent_groups &&
 125            event_groups[iter->group].events[iter->event] != NULL) {
 126         TraceEvent *ev = event_groups[iter->group].events[iter->event];
 127         iter->event++;
 128         if (event_groups[iter->group].events[iter->event] == NULL) {
 129             iter->event = 0;
 130             iter->group++;
 131         }
 132         if (!iter->pattern ||
 133             pattern_glob(iter->pattern,
 134                          trace_event_get_name(ev))) {
 135             return ev;
 136         }
 137     }
 138
 139     return NULL;
 140 }
 141
 142 void trace_list_events(void)
 143 {
 144     TraceEventIter iter;
 145     TraceEvent *ev;
 146     trace_event_iter_init(&iter, NULL);
 147     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 148         fprintf(stderr, "%s\n", trace_event_get_name(ev));
 149     }
 150 }
 151
 152 static void do_trace_enable_events(const char *line_buf)
 153 {
 154     const bool enable = ('-' != line_buf[0]);
 155     const char *line_ptr = enable ? line_buf : line_buf + 1;
 156     TraceEventIter iter;
 157     TraceEvent *ev;
 158     bool is_pattern = trace_event_is_pattern(line_ptr);
 159
 160     trace_event_iter_init(&iter, line_ptr);
 161     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 162         if (!trace_event_get_state_static(ev)) {
 163             if (!is_pattern) {
 164                 error_report("WARNING: trace event '%s' is not traceable",
 165                              line_ptr);
 166                 return;
 167             }
 168             continue;
 169         }
 170
 171         /* start tracing */
 172         trace_event_set_state_dynamic(ev, enable);
 173         if (!is_pattern) {
 174             return;
 175         }
 176     }
 177
 178     if (!is_pattern) {
 179         error_report("WARNING: trace event '%s' does not exist",
 180                      line_ptr);
 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 }