trace/control.c

   1 /*
   2  * Interface for configuring and controlling the state of tracing events.
   3  *
   4  * Copyright (C) 2011-2014 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 "trace/control.h"
  11 #ifdef CONFIG_TRACE_SIMPLE
  12 #include "trace/simple.h"
  13 #endif
  14 #ifdef CONFIG_TRACE_FTRACE
  15 #include "trace/ftrace.h"
  16 #endif
  17 #ifdef CONFIG_TRACE_LOG
  18 #include "qemu/log.h"
  19 #endif
  20 #include "qemu/error-report.h"
  21
  22 int trace_events_enabled_count;
  23 bool trace_events_dstate[TRACE_EVENT_COUNT];
  24
  25 TraceEvent *trace_event_name(const char *name)
  26 {
  27     assert(name != NULL);
  28
  29     TraceEventID i;
  30     for (i = 0; i < trace_event_count(); i++) {
  31         TraceEvent *ev = trace_event_id(i);
  32         if (strcmp(trace_event_get_name(ev), name) == 0) {
  33             return ev;
  34         }
  35     }
  36     return NULL;
  37 }
  38
  39 static bool pattern_glob(const char *pat, const char *ev)
  40 {
  41     while (*pat != '\0' && *ev != '\0') {
  42         if (*pat == *ev) {
  43             pat++;
  44             ev++;
  45         }
  46         else if (*pat == '*') {
  47             if (pattern_glob(pat, ev+1)) {
  48                 return true;
  49             } else if (pattern_glob(pat+1, ev)) {
  50                 return true;
  51             } else {
  52                 return false;
  53             }
  54         } else {
  55             return false;
  56         }
  57     }
  58
  59     while (*pat == '*') {
  60         pat++;
  61     }
  62
  63     if (*pat == '\0' && *ev == '\0') {
  64         return true;
  65     } else {
  66         return false;
  67     }
  68 }
  69
  70 TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
  71 {
  72     assert(pat != NULL);
  73
  74     TraceEventID i;
  75
  76     if (ev == NULL) {
  77         i = -1;
  78     } else {
  79         i = trace_event_get_id(ev);
  80     }
  81     i++;
  82
  83     while (i < trace_event_count()) {
  84         TraceEvent *res = trace_event_id(i);
  85         if (pattern_glob(pat, trace_event_get_name(res))) {
  86             return res;
  87         }
  88         i++;
  89     }
  90
  91     return NULL;
  92 }
  93
  94 void trace_list_events(void)
  95 {
  96     int i;
  97     for (i = 0; i < trace_event_count(); i++) {
  98         TraceEvent *res = trace_event_id(i);
  99         fprintf(stderr, "%s\n", trace_event_get_name(res));
 100     }
 101 }
 102
 103 static void do_trace_enable_events(const char *line_buf)
 104 {
 105     const bool enable = ('-' != line_buf[0]);
 106     const char *line_ptr = enable ? line_buf : line_buf + 1;
 107
 108     if (trace_event_is_pattern(line_ptr)) {
 109         TraceEvent *ev = NULL;
 110         while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
 111             if (trace_event_get_state_static(ev)) {
 112                 trace_event_set_state_dynamic(ev, enable);
 113             }
 114         }
 115     } else {
 116         TraceEvent *ev = trace_event_name(line_ptr);
 117         if (ev == NULL) {
 118             error_report("WARNING: trace event '%s' does not exist",
 119                          line_ptr);
 120         } else if (!trace_event_get_state_static(ev)) {
 121             error_report("WARNING: trace event '%s' is not traceable",
 122                          line_ptr);
 123         } else {
 124             trace_event_set_state_dynamic(ev, enable);
 125         }
 126     }
 127 }
 128
 129 void trace_enable_events(const char *line_buf)
 130 {
 131     if (is_help_option(line_buf)) {
 132         trace_list_events();
 133         exit(0);
 134     } else {
 135         do_trace_enable_events(line_buf);
 136     }
 137 }
 138
 139 void trace_init_events(const char *fname)
 140 {
 141     Location loc;
 142     FILE *fp;
 143     char line_buf[1024];
 144     size_t line_idx = 0;
 145
 146     if (fname == NULL) {
 147         return;
 148     }
 149
 150     loc_push_none(&loc);
 151     loc_set_file(fname, 0);
 152     fp = fopen(fname, "r");
 153     if (!fp) {
 154         error_report("%s", strerror(errno));
 155         exit(1);
 156     }
 157     while (fgets(line_buf, sizeof(line_buf), fp)) {
 158         loc_set_file(fname, ++line_idx);
 159         size_t len = strlen(line_buf);
 160         if (len > 1) {              /* skip empty lines */
 161             line_buf[len - 1] = '\0';
 162             if ('#' == line_buf[0]) { /* skip commented lines */
 163                 continue;
 164             }
 165             trace_enable_events(line_buf);
 166         }
 167     }
 168     if (fclose(fp) != 0) {
 169         loc_set_file(fname, 0);
 170         error_report("%s", strerror(errno));
 171         exit(1);
 172     }
 173     loc_pop(&loc);
 174 }
 175
 176 void trace_init_file(const char *file)
 177 {
 178 #ifdef CONFIG_TRACE_SIMPLE
 179     st_set_trace_file(file);
 180 #elif defined CONFIG_TRACE_LOG
 181     /* If both the simple and the log backends are enabled, "-trace file"
 182      * only applies to the simple backend; use "-D" for the log backend.
 183      */
 184     if (file) {
 185         qemu_set_log_filename(file);
 186     }
 187 #else
 188     if (file) {
 189         fprintf(stderr, "error: -trace file=...: "
 190                 "option not supported by the selected tracing backends\n");
 191         exit(1);
 192     }
 193 #endif
 194 }
 195
 196 bool trace_init_backends(void)
 197 {
 198 #ifdef CONFIG_TRACE_SIMPLE
 199     if (!st_init()) {
 200         fprintf(stderr, "failed to initialize simple tracing backend.\n");
 201         return false;
 202     }
 203 #endif
 204
 205 #ifdef CONFIG_TRACE_FTRACE
 206     if (!ftrace_init()) {
 207         fprintf(stderr, "failed to initialize ftrace backend.\n");
 208         return false;
 209     }
 210 #endif
 211
 212     return true;
 213 }