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_path[PATH_MAX]        = "/sys/kernel/tracing";
17
18static void __tracing_path_set(const char *tracing, const char *mountpoint)
19{
20	snprintf(tracing_path, sizeof(tracing_path), "%s/%s",
21		 mountpoint, tracing);
22}
23
24static const char *tracing_path_tracefs_mount(void)
25{
26	const char *mnt;
27
28	mnt = tracefs__mount();
29	if (!mnt)
30		return NULL;
31
32	__tracing_path_set("", mnt);
33
34	return tracing_path;
35}
36
37static const char *tracing_path_debugfs_mount(void)
38{
39	const char *mnt;
40
41	mnt = debugfs__mount();
42	if (!mnt)
43		return NULL;
44
45	__tracing_path_set("tracing/", mnt);
46
47	return tracing_path;
48}
49
50const char *tracing_path_mount(void)
51{
52	const char *mnt;
53
54	mnt = tracing_path_tracefs_mount();
55	if (mnt)
56		return mnt;
57
58	mnt = tracing_path_debugfs_mount();
59
60	return mnt;
61}
62
63void tracing_path_set(const char *mntpt)
64{
65	__tracing_path_set("tracing/", mntpt);
66}
67
68char *get_tracing_file(const char *name)
69{
70	char *file;
71
72	if (asprintf(&file, "%s/%s", tracing_path_mount(), name) < 0)
73		return NULL;
74
75	return file;
76}
77
78void put_tracing_file(char *file)
79{
80	free(file);
81}
82
83char *get_events_file(const char *name)
84{
85	char *file;
86
87	if (asprintf(&file, "%s/events/%s", tracing_path_mount(), name) < 0)
88		return NULL;
89
90	return file;
91}
92
93void put_events_file(char *file)
94{
95	free(file);
96}
97
98DIR *tracing_events__opendir(void)
99{
100	DIR *dir = NULL;
101	char *path = get_tracing_file("events");
102
103	if (path) {
104		dir = opendir(path);
105		put_events_file(path);
106	}
107
108	return dir;
109}
110
111int tracing_events__scandir_alphasort(struct dirent ***namelist)
112{
113	char *path = get_tracing_file("events");
114	int ret;
115
116	if (!path) {
117		*namelist = NULL;
118		return 0;
119	}
120
121	ret = scandir(path, namelist, NULL, alphasort);
122	put_events_file(path);
123
124	return ret;
125}
126
127int tracing_path__strerror_open_tp(int err, char *buf, size_t size,
128				   const char *sys, const char *name)
129{
130	char sbuf[128];
131	char filename[PATH_MAX];
132
133	snprintf(filename, PATH_MAX, "%s/%s", sys, name ?: "*");
134
135	switch (err) {
136	case ENOENT:
137		/*
138		 * We will get here if we can't find the tracepoint, but one of
139		 * debugfs or tracefs is configured, which means you probably
140		 * want some tracepoint which wasn't compiled in your kernel.
141		 * - jirka
142		 */
143		if (debugfs__configured() || tracefs__configured()) {
144			/* sdt markers */
145			if (!strncmp(filename, "sdt_", 4)) {
146				snprintf(buf, size,
147					"Error:\tFile %s/events/%s not found.\n"
148					"Hint:\tSDT event cannot be directly recorded on.\n"
149					"\tPlease first use 'perf probe %s:%s' before recording it.\n",
150					tracing_path, filename, sys, name);
151			} else {
152				snprintf(buf, size,
153					 "Error:\tFile %s/events/%s not found.\n"
154					 "Hint:\tPerhaps this kernel misses some CONFIG_ setting to enable this feature?.\n",
155					 tracing_path, filename);
156			}
157			break;
158		}
159		snprintf(buf, size, "%s",
160			 "Error:\tUnable to find debugfs/tracefs\n"
161			 "Hint:\tWas your kernel compiled with debugfs/tracefs support?\n"
162			 "Hint:\tIs the debugfs/tracefs filesystem mounted?\n"
163			 "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'");
164		break;
165	case EACCES: {
166		snprintf(buf, size,
167			 "Error:\tNo permissions to read %s/events/%s\n"
168			 "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
169			 tracing_path, filename, tracing_path_mount());
170	}
171		break;
172	default:
173		snprintf(buf, size, "%s", str_error_r(err, sbuf, sizeof(sbuf)));
174		break;
175	}
176
177	return 0;
178}
179