qemu/trace/control.c
Lluís Vilanova b1bae816c4 trace: Provide a detailed event control interface
This interface decouples event obtaining from interaction.

Events can be obtained through three different methods:

* identifier
* name
* simple wildcard pattern

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-03-28 14:19:57 +01:00

133 lines
3.4 KiB
C

/*
* Interface for configuring and controlling the state of tracing events.
*
* Copyright (C) 2011-2012 Lluís Vilanova <vilanova@ac.upc.edu>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "trace/control.h"
TraceEvent *trace_event_name(const char *name)
{
assert(name != NULL);
TraceEventID i;
for (i = 0; i < trace_event_count(); i++) {
TraceEvent *ev = trace_event_id(i);
if (strcmp(trace_event_get_name(ev), name) == 0) {
return ev;
}
}
return NULL;
}
static bool pattern_glob(const char *pat, const char *ev)
{
while (*pat != '\0' && *ev != '\0') {
if (*pat == *ev) {
pat++;
ev++;
}
else if (*pat == '*') {
if (pattern_glob(pat, ev+1)) {
return true;
} else if (pattern_glob(pat+1, ev)) {
return true;
} else {
return false;
}
} else {
return false;
}
}
while (*pat == '*') {
pat++;
}
if (*pat == '\0' && *ev == '\0') {
return true;
} else {
return false;
}
}
TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
{
assert(pat != NULL);
TraceEventID i;
if (ev == NULL) {
i = -1;
} else {
i = trace_event_get_id(ev);
}
i++;
while (i < trace_event_count()) {
TraceEvent *res = trace_event_id(i);
if (pattern_glob(pat, trace_event_get_name(res))) {
return res;
}
i++;
}
return NULL;
}
void trace_backend_init_events(const char *fname)
{
if (fname == NULL) {
return;
}
FILE *fp = fopen(fname, "r");
if (!fp) {
fprintf(stderr, "error: could not open trace events file '%s': %s\n",
fname, strerror(errno));
exit(1);
}
char line_buf[1024];
while (fgets(line_buf, sizeof(line_buf), fp)) {
size_t len = strlen(line_buf);
if (len > 1) { /* skip empty lines */
line_buf[len - 1] = '\0';
if ('#' == line_buf[0]) { /* skip commented lines */
continue;
}
const bool enable = ('-' != line_buf[0]);
char *line_ptr = enable ? line_buf : line_buf + 1;
if (trace_event_is_pattern(line_ptr)) {
TraceEvent *ev = NULL;
while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
if (trace_event_get_state_static(ev)) {
trace_event_set_state_dynamic(ev, enable);
}
}
} else {
TraceEvent *ev = trace_event_name(line_ptr);
if (ev == NULL) {
fprintf(stderr,
"error: trace event '%s' does not exist\n", line_ptr);
exit(1);
}
if (!trace_event_get_state_static(ev)) {
fprintf(stderr,
"error: trace event '%s' is not traceable\n", line_ptr);
exit(1);
}
trace_event_set_state_dynamic(ev, enable);
}
}
}
if (fclose(fp) != 0) {
fprintf(stderr, "error: closing file '%s': %s\n",
fname, strerror(errno));
exit(1);
}
}