cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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tracing_path.c (3652B)

      1// SPDX-License-Identifier: GPL-2.0
      2#ifndef _GNU_SOURCE
      3# define _GNU_SOURCE
      4#endif
      5
      6#include <stdio.h>
      7#include <stdlib.h>
      8#include <string.h>
      9#include <linux/string.h>
     10#include <errno.h>
     11#include <unistd.h>
     12#include "fs.h"
     13
     14#include "tracing_path.h"
     15
     16static char tracing_mnt[PATH_MAX]  = "/sys/kernel/debug";
     17static char tracing_path[PATH_MAX]        = "/sys/kernel/debug/tracing";
     18static char tracing_events_path[PATH_MAX] = "/sys/kernel/debug/tracing/events";
     19
     20static void __tracing_path_set(const char *tracing, const char *mountpoint)
     21{
     22	snprintf(tracing_mnt, sizeof(tracing_mnt), "%s", mountpoint);
     23	snprintf(tracing_path, sizeof(tracing_path), "%s/%s",
     24		 mountpoint, tracing);
     25	snprintf(tracing_events_path, sizeof(tracing_events_path), "%s/%s%s",
     26		 mountpoint, tracing, "events");
     27}
     28
     29static const char *tracing_path_tracefs_mount(void)
     30{
     31	const char *mnt;
     32
     33	mnt = tracefs__mount();
     34	if (!mnt)
     35		return NULL;
     36
     37	__tracing_path_set("", mnt);
     38
     39	return tracing_path;
     40}
     41
     42static const char *tracing_path_debugfs_mount(void)
     43{
     44	const char *mnt;
     45
     46	mnt = debugfs__mount();
     47	if (!mnt)
     48		return NULL;
     49
     50	__tracing_path_set("tracing/", mnt);
     51
     52	return tracing_path;
     53}
     54
     55const char *tracing_path_mount(void)
     56{
     57	const char *mnt;
     58
     59	mnt = tracing_path_tracefs_mount();
     60	if (mnt)
     61		return mnt;
     62
     63	mnt = tracing_path_debugfs_mount();
     64
     65	return mnt;
     66}
     67
     68void tracing_path_set(const char *mntpt)
     69{
     70	__tracing_path_set("tracing/", mntpt);
     71}
     72
     73char *get_tracing_file(const char *name)
     74{
     75	char *file;
     76
     77	if (asprintf(&file, "%s/%s", tracing_path_mount(), name) < 0)
     78		return NULL;
     79
     80	return file;
     81}
     82
     83void put_tracing_file(char *file)
     84{
     85	free(file);
     86}
     87
     88char *get_events_file(const char *name)
     89{
     90	char *file;
     91
     92	if (asprintf(&file, "%s/events/%s", tracing_path_mount(), name) < 0)
     93		return NULL;
     94
     95	return file;
     96}
     97
     98void put_events_file(char *file)
     99{
    100	free(file);
    101}
    102
    103DIR *tracing_events__opendir(void)
    104{
    105	DIR *dir = NULL;
    106	char *path = get_tracing_file("events");
    107
    108	if (path) {
    109		dir = opendir(path);
    110		put_events_file(path);
    111	}
    112
    113	return dir;
    114}
    115
    116int tracing_path__strerror_open_tp(int err, char *buf, size_t size,
    117				   const char *sys, const char *name)
    118{
    119	char sbuf[128];
    120	char filename[PATH_MAX];
    121
    122	snprintf(filename, PATH_MAX, "%s/%s", sys, name ?: "*");
    123
    124	switch (err) {
    125	case ENOENT:
    126		/*
    127		 * We will get here if we can't find the tracepoint, but one of
    128		 * debugfs or tracefs is configured, which means you probably
    129		 * want some tracepoint which wasn't compiled in your kernel.
    130		 * - jirka
    131		 */
    132		if (debugfs__configured() || tracefs__configured()) {
    133			/* sdt markers */
    134			if (!strncmp(filename, "sdt_", 4)) {
    135				snprintf(buf, size,
    136					"Error:\tFile %s/%s not found.\n"
    137					"Hint:\tSDT event cannot be directly recorded on.\n"
    138					"\tPlease first use 'perf probe %s:%s' before recording it.\n",
    139					tracing_events_path, filename, sys, name);
    140			} else {
    141				snprintf(buf, size,
    142					 "Error:\tFile %s/%s not found.\n"
    143					 "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n",
    144					 tracing_events_path, filename);
    145			}
    146			break;
    147		}
    148		snprintf(buf, size, "%s",
    149			 "Error:\tUnable to find debugfs/tracefs\n"
    150			 "Hint:\tWas your kernel compiled with debugfs/tracefs support?\n"
    151			 "Hint:\tIs the debugfs/tracefs filesystem mounted?\n"
    152			 "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'");
    153		break;
    154	case EACCES: {
    155		snprintf(buf, size,
    156			 "Error:\tNo permissions to read %s/%s\n"
    157			 "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
    158			 tracing_events_path, filename, tracing_path_mount());
    159	}
    160		break;
    161	default:
    162		snprintf(buf, size, "%s", str_error_r(err, sbuf, sizeof(sbuf)));
    163		break;
    164	}
    165
    166	return 0;
    167}