*
*/
-#include <stdio.h>
-#include <string.h>
-#include <fcntl.h>
-#include <limits.h>
-#include "trace.h"
+#include "qemu/osdep.h"
#include "trace/control.h"
+#include "trace/ftrace.h"
int trace_marker_fd;
-static int find_debugfs(char *debugfs)
+static int find_mount(char *mount_point, const char *fstype)
{
char type[100];
FILE *fp;
+ int ret = 0;
fp = fopen("/proc/mounts", "r");
if (fp == NULL) {
}
while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
- debugfs, type) == 2) {
- if (strcmp(type, "debugfs") == 0) {
+ mount_point, type) == 2) {
+ if (strcmp(type, fstype) == 0) {
+ ret = 1;
break;
}
}
fclose(fp);
- if (strcmp(type, "debugfs") != 0) {
- return 0;
- }
- return 1;
+ return ret;
}
bool ftrace_init(void)
{
- char debugfs[PATH_MAX];
+ char mount_point[PATH_MAX];
char path[PATH_MAX];
- int debugfs_found;
+ int tracefs_found;
int trace_fd = -1;
+ const char *subdir = "";
- debugfs_found = find_debugfs(debugfs);
- if (debugfs_found) {
- snprintf(path, PATH_MAX, "%s/tracing/tracing_on", debugfs);
+ tracefs_found = find_mount(mount_point, "tracefs");
+ if (!tracefs_found) {
+ tracefs_found = find_mount(mount_point, "debugfs");
+ subdir = "/tracing";
+ }
+
+ if (tracefs_found) {
+ if (snprintf(path, PATH_MAX, "%s%s/tracing_on", mount_point, subdir)
+ >= sizeof(path)) {
+ fprintf(stderr, "Using tracefs mountpoint would exceed PATH_MAX\n");
+ return false;
+ }
trace_fd = open(path, O_WRONLY);
if (trace_fd < 0) {
+ if (errno == EACCES) {
+ trace_marker_fd = open("/dev/null", O_WRONLY);
+ if (trace_marker_fd != -1) {
+ return true;
+ }
+ }
perror("Could not open ftrace 'tracing_on' file");
return false;
} else {
}
close(trace_fd);
}
- snprintf(path, PATH_MAX, "%s/tracing/trace_marker", debugfs);
+ if (snprintf(path, PATH_MAX, "%s%s/trace_marker", mount_point, subdir)
+ >= sizeof(path)) {
+ fprintf(stderr, "Using tracefs mountpoint would exceed PATH_MAX\n");
+ return false;
+ }
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");
+ fprintf(stderr, "tracefs is not mounted\n");
return false;
}