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