qemu-e2k/trace/control.c
Gerd Hoffmann ddde8acc98 trace: allow disabling events in events file
Disable trace events prefixed with a '-'.  Useful
to enable a group of tracepoints with exceptions,
like this:

  usb_xhci_port_*
  -usb_xhci_port_read

which will enable all xhci port tracepoints except reads.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2012-11-16 13:12:13 +01:00

53 lines
1.4 KiB
C

/*
* Interface for configuring and controlling the state of tracing events.
*
* Copyright (C) 2011 Lluís Vilanova <vilanova@ac.upc.edu>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*/
#include "trace/control.h"
void trace_backend_init_events(const char *fname)
{
int ret;
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;
}
if ('-' == line_buf[0]) {
ret = trace_event_set_state(line_buf+1, false);
} else {
ret = trace_event_set_state(line_buf, true);
}
if (!ret) {
fprintf(stderr,
"error: trace event '%s' does not exist\n", line_buf);
exit(1);
}
}
}
if (fclose(fp) != 0) {
fprintf(stderr, "error: closing file '%s': %s\n",
fname, strerror(errno));
exit(1);
}
}