summaryrefslogtreecommitdiffstats
path: root/tools/perf/util/vdso.c
blob: cffcda448c2820c7d51074188db8a90f901cea0c (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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <linux/kernel.h>

#include "vdso.h"
#include "util.h"
#include "symbol.h"
#include "machine.h"
#include "thread.h"
#include "linux/string.h"
#include "debug.h"

/*
 * Include definition of find_vdso_map() also used in perf-read-vdso.c for
 * building perf-read-vdso32 and perf-read-vdsox32.
 */
#include "find-vdso-map.c"

#define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX"

struct vdso_file {
	bool found;
	bool error;
	char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)];
	const char *dso_name;
	const char *read_prog;
};

struct vdso_info {
	struct vdso_file vdso;
#if BITS_PER_LONG == 64
	struct vdso_file vdso32;
	struct vdso_file vdsox32;
#endif
};

static struct vdso_info *vdso_info__new(void)
{
	static const struct vdso_info vdso_info_init = {
		.vdso    = {
			.temp_file_name = VDSO__TEMP_FILE_NAME,
			.dso_name = DSO__NAME_VDSO,
		},
#if BITS_PER_LONG == 64
		.vdso32  = {
			.temp_file_name = VDSO__TEMP_FILE_NAME,
			.dso_name = DSO__NAME_VDSO32,
			.read_prog = "perf-read-vdso32",
		},
		.vdsox32  = {
			.temp_file_name = VDSO__TEMP_FILE_NAME,
			.dso_name = DSO__NAME_VDSOX32,
			.read_prog = "perf-read-vdsox32",
		},
#endif
	};

	return memdup(&vdso_info_init, sizeof(vdso_info_init));
}

static char *get_file(struct vdso_file *vdso_file)
{
	char *vdso = NULL;
	char *buf = NULL;
	void *start, *end;
	size_t size;
	int fd;

	if (vdso_file->found)
		return vdso_file->temp_file_name;

	if (vdso_file->error || find_vdso_map(&start, &end))
		return NULL;

	size = end - start;

	buf = memdup(start, size);
	if (!buf)
		return NULL;

	fd = mkstemp(vdso_file->temp_file_name);
	if (fd < 0)
		goto out;

	if (size == (size_t) write(fd, buf, size))
		vdso = vdso_file->temp_file_name;

	close(fd);

 out:
	free(buf);

	vdso_file->found = (vdso != NULL);
	vdso_file->error = !vdso_file->found;
	return vdso;
}

void machine__exit_vdso(struct machine *machine)
{
	struct vdso_info *vdso_info = machine->vdso_info;

	if (!vdso_info)
		return;

	if (vdso_info->vdso.found)
		unlink(vdso_info->vdso.temp_file_name);
#if BITS_PER_LONG == 64
	if (vdso_info->vdso32.found)
		unlink(vdso_info->vdso32.temp_file_name);
	if (vdso_info->vdsox32.found)
		unlink(vdso_info->vdsox32.temp_file_name);
#endif

	zfree(&machine->vdso_info);
}

static struct dso *__machine__addnew_vdso(struct machine *machine, const char *short_name,
					  const char *long_name)
{
	struct dso *dso;

	dso = dso__new(short_name);
	if (dso != NULL) {
		__dsos__add(&machine->dsos, dso);
		dso__set_long_name(dso, long_name, false);
	}

	return dso;
}

static enum dso_type machine__thread_dso_type(struct machine *machine,
					      struct thread *thread)
{
	enum dso_type dso_type = DSO__TYPE_UNKNOWN;
	struct map *map;
	struct dso *dso;

	map = map_groups__first(thread->mg, MAP__FUNCTION);
	for (; map ; map = map_groups__next(map)) {
		dso = map->dso;
		if (!dso || dso->long_name[0] != '/')
			continue;
		dso_type = dso__type(dso, machine);
		if (dso_type != DSO__TYPE_UNKNOWN)
			break;
	}

	return dso_type;
}

#if BITS_PER_LONG == 64

static int vdso__do_copy_compat(FILE *f, int fd)
{
	char buf[4096];
	size_t count;

	while (1) {
		count = fread(buf, 1, sizeof(buf), f);
		if (ferror(f))
			return -errno;
		if (feof(f))
			break;
		if (count && writen(fd, buf, count) != (ssize_t)count)
			return -errno;
	}

	return 0;
}

static int vdso__copy_compat(const char *prog, int fd)
{
	FILE *f;
	int err;

	f = popen(prog, "r");
	if (!f)
		return -errno;

	err = vdso__do_copy_compat(f, fd);

	if (pclose(f) == -1)
		return -errno;

	return err;
}

static int vdso__create_compat_file(const char *prog, char *temp_name)
{
	int fd, err;

	fd = mkstemp(temp_name);
	if (fd < 0)
		return -errno;

	err = vdso__copy_compat(prog, fd);

	if (close(fd) == -1)
		return -errno;

	return err;
}

static const char *vdso__get_compat_file(struct vdso_file *vdso_file)
{
	int err;

	if (vdso_file->found)
		return vdso_file->temp_file_name;

	if (vdso_file->error)
		return NULL;

	err = vdso__create_compat_file(vdso_file->read_prog,
				       vdso_file->temp_file_name);
	if (err) {
		pr_err("%s failed, error %d\n", vdso_file->read_prog, err);
		vdso_file->error = true;
		return NULL;
	}

	vdso_file->found = true;

	return vdso_file->temp_file_name;
}

static struct dso *__machine__findnew_compat(struct machine *machine,
					     struct vdso_file *vdso_file)
{
	const char *file_name;
	struct dso *dso;

	dso = __dsos__find(&machine->dsos, vdso_file->dso_name, true);
	if (dso)
		goto out;

	file_name = vdso__get_compat_file(vdso_file);
	if (!file_name)
		goto out;

	dso = __machine__addnew_vdso(machine, vdso_file->dso_name, file_name);
out:
	return dso;
}

static int __machine__findnew_vdso_compat(struct machine *machine,
					  struct thread *thread,
					  struct vdso_info *vdso_info,
					  struct dso **dso)
{
	enum dso_type dso_type;

	dso_type = machine__thread_dso_type(machine, thread);

#ifndef HAVE_PERF_READ_VDSO32
	if (dso_type == DSO__TYPE_32BIT)
		return 0;
#endif
#ifndef HAVE_PERF_READ_VDSOX32
	if (dso_type == DSO__TYPE_X32BIT)
		return 0;
#endif

	switch (dso_type) {
	case DSO__TYPE_32BIT:
		*dso = __machine__findnew_compat(machine, &vdso_info->vdso32);
		return 1;
	case DSO__TYPE_X32BIT:
		*dso = __machine__findnew_compat(machine, &vdso_info->vdsox32);
		return 1;
	case DSO__TYPE_UNKNOWN:
	case DSO__TYPE_64BIT:
	default:
		return 0;
	}
}

#endif

static struct dso *machine__find_vdso(struct machine *machine,
				      struct thread *thread)
{
	struct dso *dso = NULL;
	enum dso_type dso_type;

	dso_type = machine__thread_dso_type(machine, thread);
	switch (dso_type) {
	case DSO__TYPE_32BIT:
		dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO32, true);
		if (!dso) {
			dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO,
					   true);
			if (dso && dso_type != dso__type(dso, machine))
				dso = NULL;
		}
		break;
	case DSO__TYPE_X32BIT:
		dso = __dsos__find(&machine->dsos, DSO__NAME_VDSOX32, true);
		break;
	case DSO__TYPE_64BIT:
	case DSO__TYPE_UNKNOWN:
	default:
		dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
		break;
	}

	return dso;
}

struct dso *machine__findnew_vdso(struct machine *machine,
				  struct thread *thread)
{
	struct vdso_info *vdso_info;
	struct dso *dso = NULL;

	pthread_rwlock_wrlock(&machine->dsos.lock);
	if (!machine->vdso_info)
		machine->vdso_info = vdso_info__new();

	vdso_info = machine->vdso_info;
	if (!vdso_info)
		goto out_unlock;

	dso = machine__find_vdso(machine, thread);
	if (dso)
		goto out_unlock;

#if BITS_PER_LONG == 64
	if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso))
		goto out_unlock;
#endif

	dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
	if (!dso) {
		char *file;

		file = get_file(&vdso_info->vdso);
		if (file)
			dso = __machine__addnew_vdso(machine, DSO__NAME_VDSO, file);
	}

out_unlock:
	dso__get(dso);
	pthread_rwlock_unlock(&machine->dsos.lock);
	return dso;
}

bool dso__is_vdso(struct dso *dso)
{
	return !strcmp(dso->short_name, DSO__NAME_VDSO) ||
	       !strcmp(dso->short_name, DSO__NAME_VDSO32) ||
	       !strcmp(dso->short_name, DSO__NAME_VDSOX32);
}