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_events__scandir_alphasort(struct dirent ***namelist)
117{
118	char *path = get_tracing_file("events");
119	int ret;
120
121	if (!path) {
122		*namelist = NULL;
123		return 0;
124	}
125
126	ret = scandir(path, namelist, NULL, alphasort);
127	put_events_file(path);
128
129	return ret;
130}
131
132int tracing_path__strerror_open_tp(int err, char *buf, size_t size,
133				   const char *sys, const char *name)
134{
135	char sbuf[128];
136	char filename[PATH_MAX];
137
138	snprintf(filename, PATH_MAX, "%s/%s", sys, name ?: "*");
139
140	switch (err) {
141	case ENOENT:
142		/*
143		 * We will get here if we can't find the tracepoint, but one of
144		 * debugfs or tracefs is configured, which means you probably
145		 * want some tracepoint which wasn't compiled in your kernel.
146		 * - jirka
147		 */
148		if (debugfs__configured() || tracefs__configured()) {
149			/* sdt markers */
150			if (!strncmp(filename, "sdt_", 4)) {
151				snprintf(buf, size,
152					"Error:\tFile %s/%s not found.\n"
153					"Hint:\tSDT event cannot be directly recorded on.\n"
154					"\tPlease first use 'perf probe %s:%s' before recording it.\n",
155					tracing_events_path, filename, sys, name);
156			} else {
157				snprintf(buf, size,
158					 "Error:\tFile %s/%s not found.\n"
159					 "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n",
160					 tracing_events_path, filename);
161			}
162			break;
163		}
164		snprintf(buf, size, "%s",
165			 "Error:\tUnable to find debugfs/tracefs\n"
166			 "Hint:\tWas your kernel compiled with debugfs/tracefs support?\n"
167			 "Hint:\tIs the debugfs/tracefs filesystem mounted?\n"
168			 "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'");
169		break;
170	case EACCES: {
171		snprintf(buf, size,
172			 "Error:\tNo permissions to read %s/%s\n"
173			 "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
174			 tracing_events_path, filename, tracing_path_mount());
175	}
176		break;
177	default:
178		snprintf(buf, size, "%s", str_error_r(err, sbuf, sizeof(sbuf)));
179		break;
180	}
181
182	return 0;
183}