bool ftrace_init(void)
{
char debugfs[PATH_MAX];
char path[PATH_MAX];
int debugfs_found;
int trace_fd = -1;
debugfs_found = find_debugfs(debugfs);
if (debugfs_found) {
snprintf(path, PATH_MAX, "%s/tracing/tracing_on", debugfs);
trace_fd = open(path, O_WRONLY);
if (trace_fd < 0) {
perror("Could not open ftrace 'tracing_on' file");
return false;
} else {
if (write(trace_fd, "1", 1) < 0) {
perror("Could not write to 'tracing_on' file");
close(trace_fd);
return false;
}
close(trace_fd);
}
snprintf(path, PATH_MAX, "%s/tracing/trace_marker", debugfs);
trace_marker_fd = open(path, O_WRONLY);
if (trace_marker_fd < 0) {
perror("Could not open ftrace 'trace_marker' file");
return false;
}
} else {
fprintf(stderr, "debugfs is not mounted\n");
return false;
}
return true;
}
int main(int argc, char **argv)
{
const char *dfs = find_debugfs();
if (!dfs)
die("could not find debugfs");
return 0;
}
/*
* Finds the path to the debugfs/tracing
* Allocates the string and stores it.
*/
static const char *find_tracing_dir(void)
{
static char *tracing;
static int tracing_found;
const char *debugfs;
if (tracing_found)
return tracing;
debugfs = find_debugfs();
tracing = malloc_or_die(strlen(debugfs) + 9);
sprintf(tracing, "%s/tracing", debugfs);
tracing_found = 1;
return tracing;
}
static const char *find_trace(void)
{
static char t[MAX_PATH + 1];
if (t[0] != '\0')
return t;
const char *mt = getenv("T");
if (mt)
strcpy(t, mt);
if (t[0] != '\0')
return t;
const char *d = find_debugfs();
if (!d)
return NULL;
strcpy(t, d);
strcat(t, "/trace/trace");
return t;
}
/*
* Finds the path to the debugfs/tracing
* Allocates the string and stores it.
*/
const char *find_tracing_dir(void)
{
const char *tracing_dir = "";
static char *tracing;
static int tracing_found;
const char *debugfs;
if (tracing_found)
return tracing;
debugfs = find_tracefs();
if (!debugfs) {
tracing_dir = "/tracing";
debugfs = find_debugfs();
if (!debugfs)
return NULL;
}
if (asprintf(&tracing, "%s%s", debugfs, tracing_dir) < 0)
return NULL;
tracing_found = 1;
return tracing;
}
