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// SPDX-License-Identifier: GPL-2.0
#ifndef _GNU_SOURCE
# define _GNU_SOURCE
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <linux/string.h>
#include <errno.h>
#include <unistd.h>
#include "fs.h"
#include "tracing_path.h"
char tracing_mnt[PATH_MAX] = "/sys/kernel/debug";
char tracing_path[PATH_MAX] = "/sys/kernel/debug/tracing";
char tracing_events_path[PATH_MAX] = "/sys/kernel/debug/tracing/events";
static void __tracing_path_set(const char *tracing, const char *mountpoint)
{
snprintf(tracing_mnt, sizeof(tracing_mnt), "%s", mountpoint);
snprintf(tracing_path, sizeof(tracing_path), "%s/%s",
mountpoint, tracing);
snprintf(tracing_events_path, sizeof(tracing_events_path), "%s/%s%s",
mountpoint, tracing, "events");
}
static const char *tracing_path_tracefs_mount(void)
{
const char *mnt;
mnt = tracefs__mount();
if (!mnt)
return NULL;
__tracing_path_set("", mnt);
return mnt;
}
static const char *tracing_path_debugfs_mount(void)
{
const char *mnt;
mnt = debugfs__mount();
if (!mnt)
return NULL;
__tracing_path_set("tracing/", mnt);
return mnt;
}
const char *tracing_path_mount(void)
{
const char *mnt;
mnt = tracing_path_tracefs_mount();
if (mnt)
return mnt;
mnt = tracing_path_debugfs_mount();
return mnt;
}
void tracing_path_set(const char *mntpt)
{
__tracing_path_set("tracing/", mntpt);
}
char *get_tracing_file(const char *name)
{
char *file;
if (asprintf(&file, "%s/%s", tracing_path, name) < 0)
return NULL;
return file;
}
void put_tracing_file(char *file)
{
free(file);
}
int tracing_path__strerror_open_tp(int err, char *buf, size_t size,
const char *sys, const char *name)
{
char sbuf[128];
char filename[PATH_MAX];
snprintf(filename, PATH_MAX, "%s/%s", sys, name ?: "*");
switch (err) {
case ENOENT:
/*
* We will get here if we can't find the tracepoint, but one of
* debugfs or tracefs is configured, which means you probably
* want some tracepoint which wasn't compiled in your kernel.
* - jirka
*/
if (debugfs__configured() || tracefs__configured()) {
/* sdt markers */
if (!strncmp(filename, "sdt_", 4)) {
snprintf(buf, size,
"Error:\tFile %s/%s not found.\n"
"Hint:\tSDT event cannot be directly recorded on.\n"
"\tPlease first use 'perf probe %s:%s' before recording it.\n",
tracing_events_path, filename, sys, name);
} else {
snprintf(buf, size,
"Error:\tFile %s/%s not found.\n"
"Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n",
tracing_events_path, filename);
}
break;
}
snprintf(buf, size, "%s",
"Error:\tUnable to find debugfs/tracefs\n"
"Hint:\tWas your kernel compiled with debugfs/tracefs support?\n"
"Hint:\tIs the debugfs/tracefs filesystem mounted?\n"
"Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'");
break;
case EACCES: {
snprintf(buf, size,
"Error:\tNo permissions to read %s/%s\n"
"Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
tracing_events_path, filename, tracing_mnt);
}
break;
default:
snprintf(buf, size, "%s", str_error_r(err, sbuf, sizeof(sbuf)));
break;
}
return 0;
}
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