qemu/trace/control.c
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   1/*
   2 * Interface for configuring and controlling the state of tracing events.
   3 *
   4 * Copyright (C) 2011-2016 LluĂ­s 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
  32int trace_events_enabled_count;
  33
  34typedef struct TraceEventGroup {
  35    TraceEvent **events;
  36} TraceEventGroup;
  37
  38static TraceEventGroup *event_groups;
  39static size_t nevent_groups;
  40static uint32_t next_id;
  41static uint32_t next_vcpu_id;
  42
  43QemuOptsList 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
  64void 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
  86TraceEvent *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
 101static 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
 133void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
 134{
 135    iter->event = 0;
 136    iter->group = 0;
 137    iter->pattern = pattern;
 138}
 139
 140TraceEvent *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
 160void 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}
 169
 170static void do_trace_enable_events(const char *line_buf)
 171{
 172    const bool enable = ('-' != line_buf[0]);
 173    const char *line_ptr = enable ? line_buf : line_buf + 1;
 174    TraceEventIter iter;
 175    TraceEvent *ev;
 176    bool is_pattern = trace_event_is_pattern(line_ptr);
 177
 178    trace_event_iter_init(&iter, line_ptr);
 179    while ((ev = trace_event_iter_next(&iter)) != NULL) {
 180        if (!trace_event_get_state_static(ev)) {
 181            if (!is_pattern) {
 182                warn_report("trace event '%s' is not traceable",
 183                            line_ptr);
 184                return;
 185            }
 186            continue;
 187        }
 188
 189        /* start tracing */
 190        trace_event_set_state_dynamic(ev, enable);
 191        if (!is_pattern) {
 192            return;
 193        }
 194    }
 195
 196    if (!is_pattern) {
 197        warn_report("trace event '%s' does not exist",
 198                    line_ptr);
 199    }
 200}
 201
 202void trace_enable_events(const char *line_buf)
 203{
 204    if (is_help_option(line_buf)) {
 205        trace_list_events();
 206        if (cur_mon == NULL) {
 207            exit(0);
 208        }
 209    } else {
 210        do_trace_enable_events(line_buf);
 211    }
 212}
 213
 214static void trace_init_events(const char *fname)
 215{
 216    Location loc;
 217    FILE *fp;
 218    char line_buf[1024];
 219    size_t line_idx = 0;
 220
 221    if (fname == NULL) {
 222        return;
 223    }
 224
 225    loc_push_none(&loc);
 226    loc_set_file(fname, 0);
 227    fp = fopen(fname, "r");
 228    if (!fp) {
 229        error_report("%s", strerror(errno));
 230        exit(1);
 231    }
 232    while (fgets(line_buf, sizeof(line_buf), fp)) {
 233        loc_set_file(fname, ++line_idx);
 234        size_t len = strlen(line_buf);
 235        if (len > 1) {              /* skip empty lines */
 236            line_buf[len - 1] = '\0';
 237            if ('#' == line_buf[0]) { /* skip commented lines */
 238                continue;
 239            }
 240            trace_enable_events(line_buf);
 241        }
 242    }
 243    if (fclose(fp) != 0) {
 244        loc_set_file(fname, 0);
 245        error_report("%s", strerror(errno));
 246        exit(1);
 247    }
 248    loc_pop(&loc);
 249}
 250
 251void trace_init_file(const char *file)
 252{
 253#ifdef CONFIG_TRACE_SIMPLE
 254    st_set_trace_file(file);
 255#elif defined CONFIG_TRACE_LOG
 256    /* If both the simple and the log backends are enabled, "-trace file"
 257     * only applies to the simple backend; use "-D" for the log backend.
 258     */
 259    if (file) {
 260        qemu_set_log_filename(file, &error_fatal);
 261    }
 262#else
 263    if (file) {
 264        fprintf(stderr, "error: -trace file=...: "
 265                "option not supported by the selected tracing backends\n");
 266        exit(1);
 267    }
 268#endif
 269}
 270
 271void trace_fini_vcpu(CPUState *vcpu)
 272{
 273    TraceEventIter iter;
 274    TraceEvent *ev;
 275
 276    trace_guest_cpu_exit(vcpu);
 277
 278    trace_event_iter_init(&iter, NULL);
 279    while ((ev = trace_event_iter_next(&iter)) != NULL) {
 280        if (trace_event_is_vcpu(ev) &&
 281            trace_event_get_state_static(ev) &&
 282            trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
 283            /* must disable to affect the global counter */
 284            trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
 285        }
 286    }
 287}
 288
 289bool trace_init_backends(void)
 290{
 291#ifdef CONFIG_TRACE_SIMPLE
 292    if (!st_init()) {
 293        fprintf(stderr, "failed to initialize simple tracing backend.\n");
 294        return false;
 295    }
 296#endif
 297
 298#ifdef CONFIG_TRACE_FTRACE
 299    if (!ftrace_init()) {
 300        fprintf(stderr, "failed to initialize ftrace backend.\n");
 301        return false;
 302    }
 303#endif
 304
 305#ifdef CONFIG_TRACE_SYSLOG
 306    openlog(NULL, LOG_PID, LOG_DAEMON);
 307#endif
 308
 309    return true;
 310}
 311
 312char *trace_opt_parse(const char *optarg)
 313{
 314    char *trace_file;
 315    QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
 316                                             optarg, true);
 317    if (!opts) {
 318        exit(1);
 319    }
 320    if (qemu_opt_get(opts, "enable")) {
 321        trace_enable_events(qemu_opt_get(opts, "enable"));
 322    }
 323    trace_init_events(qemu_opt_get(opts, "events"));
 324    trace_file = g_strdup(qemu_opt_get(opts, "file"));
 325    qemu_opts_del(opts);
 326
 327    return trace_file;
 328}
 329
 330uint32_t trace_get_vcpu_event_count(void)
 331{
 332    return next_vcpu_id;
 333}
 334