aboutsummaryrefslogtreecommitdiffstats
path: root/tools/lib/api/fs/tracing_path.c
blob: 5afb11b30fca4e318f88aaf9e7e28b0c2d4107b8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
// 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"

static char tracing_mnt[PATH_MAX]  = "/sys/kernel/debug";
static char tracing_path[PATH_MAX]        = "/sys/kernel/debug/tracing";
static 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 tracing_path;
}

static const char *tracing_path_debugfs_mount(void)
{
	const char *mnt;

	mnt = debugfs__mount();
	if (!mnt)
		return NULL;

	__tracing_path_set("tracing/", mnt);

	return tracing_path;
}

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_mount(), name) < 0)
		return NULL;

	return file;
}

void put_tracing_file(char *file)
{
	free(file);
}

char *get_events_file(const char *name)
{
	char *file;

	if (asprintf(&file, "%s/events/%s", tracing_path_mount(), name) < 0)
		return NULL;

	return file;
}

void put_events_file(char *file)
{
	free(file);
}

DIR *tracing_events__opendir(void)
{
	DIR *dir = NULL;
	char *path = get_tracing_file("events");

	if (path) {
		dir = opendir(path);
		put_events_file(path);
	}

	return dir;
}

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_path_mount());
	}
		break;
	default:
		snprintf(buf, size, "%s", str_error_r(err, sbuf, sizeof(sbuf)));
		break;
	}

	return 0;
}

Privacy Policy