trace/control.c

   1 /*
   2  * Interface for configuring and controlling the state of tracing events.
   3  *
   4  * Copyright (C) 2011-2012 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
  12
  13 TraceEvent *trace_event_name(const char *name)
  14 {
  15     assert(name != NULL);
  16
  17     TraceEventID i;
  18     for (i = 0; i < trace_event_count(); i++) {
  19         TraceEvent *ev = trace_event_id(i);
  20         if (strcmp(trace_event_get_name(ev), name) == 0) {
  21             return ev;
  22         }
  23     }
  24     return NULL;
  25 }
  26
  27 static bool pattern_glob(const char *pat, const char *ev)
  28 {
  29     while (*pat != '\0' && *ev != '\0') {
  30         if (*pat == *ev) {
  31             pat++;
  32             ev++;
  33         }
  34         else if (*pat == '*') {
  35             if (pattern_glob(pat, ev+1)) {
  36                 return true;
  37             } else if (pattern_glob(pat+1, ev)) {
  38                 return true;
  39             } else {
  40                 return false;
  41             }
  42         } else {
  43             return false;
  44         }
  45     }
  46
  47     while (*pat == '*') {
  48         pat++;
  49     }
  50
  51     if (*pat == '\0' && *ev == '\0') {
  52         return true;
  53     } else {
  54         return false;
  55     }
  56 }
  57
  58 TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
  59 {
  60     assert(pat != NULL);
  61
  62     TraceEventID i;
  63
  64     if (ev == NULL) {
  65         i = -1;
  66     } else {
  67         i = trace_event_get_id(ev);
  68     }
  69     i++;
  70
  71     while (i < trace_event_count()) {
  72         TraceEvent *res = trace_event_id(i);
  73         if (pattern_glob(pat, trace_event_get_name(res))) {
  74             return res;
  75         }
  76         i++;
  77     }
  78
  79     return NULL;
  80 }
  81
  82 void trace_backend_init_events(const char *fname)
  83 {
  84     if (fname == NULL) {
  85         return;
  86     }
  87
  88     FILE *fp = fopen(fname, "r");
  89     if (!fp) {
  90         fprintf(stderr, "error: could not open trace events file '%s': %s\n",
  91                 fname, strerror(errno));
  92         exit(1);
  93     }
  94     char line_buf[1024];
  95     while (fgets(line_buf, sizeof(line_buf), fp)) {
  96         size_t len = strlen(line_buf);
  97         if (len > 1) {              /* skip empty lines */
  98             line_buf[len - 1] = '\0';
  99             if ('#' == line_buf[0]) { /* skip commented lines */
 100                 continue;
 101             }
 102             const bool enable = ('-' != line_buf[0]);
 103             char *line_ptr = enable ? line_buf : line_buf + 1;
 104             if (trace_event_is_pattern(line_ptr)) {
 105                 TraceEvent *ev = NULL;
 106                 while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
 107                     if (trace_event_get_state_static(ev)) {
 108                         trace_event_set_state_dynamic(ev, enable);
 109                     }
 110                 }
 111             } else {
 112                 TraceEvent *ev = trace_event_name(line_ptr);
 113                 if (ev == NULL) {
 114                     fprintf(stderr,
 115                             "error: trace event '%s' does not exist\n", line_ptr);
 116                     exit(1);
 117                 }
 118                 if (!trace_event_get_state_static(ev)) {
 119                     fprintf(stderr,
 120                             "error: trace event '%s' is not traceable\n", line_ptr);
 121                     exit(1);
 122                 }
 123                 trace_event_set_state_dynamic(ev, enable);
 124             }
 125         }
 126     }
 127     if (fclose(fp) != 0) {
 128         fprintf(stderr, "error: closing file '%s': %s\n",
 129                 fname, strerror(errno));
 130         exit(1);
 131     }
 132 }