1
2#include <unistd.h>
3#include <stdio.h>
4#include <string.h>
5#include <sys/types.h>
6#include <sys/stat.h>
7#include <fcntl.h>
8#include <stdlib.h>
9#include <linux/kernel.h>
10
11#include "vdso.h"
12#include "util.h"
13#include "symbol.h"
14#include "machine.h"
15#include "thread.h"
16#include "linux/string.h"
17#include "debug.h"
18
19/*
20 * Include definition of find_vdso_map() also used in perf-read-vdso.c for
21 * building perf-read-vdso32 and perf-read-vdsox32.
22 */
23#include "find-vdso-map.c"
24
25#define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX"
26
27struct vdso_file {
28	bool found;
29	bool error;
30	char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)];
31	const char *dso_name;
32	const char *read_prog;
33};
34
35struct vdso_info {
36	struct vdso_file vdso;
37#if BITS_PER_LONG == 64
38	struct vdso_file vdso32;
39	struct vdso_file vdsox32;
40#endif
41};
42
43static struct vdso_info *vdso_info__new(void)
44{
45	static const struct vdso_info vdso_info_init = {
46		.vdso    = {
47			.temp_file_name = VDSO__TEMP_FILE_NAME,
48			.dso_name = DSO__NAME_VDSO,
49		},
50#if BITS_PER_LONG == 64
51		.vdso32  = {
52			.temp_file_name = VDSO__TEMP_FILE_NAME,
53			.dso_name = DSO__NAME_VDSO32,
54			.read_prog = "perf-read-vdso32",
55		},
56		.vdsox32  = {
57			.temp_file_name = VDSO__TEMP_FILE_NAME,
58			.dso_name = DSO__NAME_VDSOX32,
59			.read_prog = "perf-read-vdsox32",
60		},
61#endif
62	};
63
64	return memdup(&vdso_info_init, sizeof(vdso_info_init));
65}
66
67static char *get_file(struct vdso_file *vdso_file)
68{
69	char *vdso = NULL;
70	char *buf = NULL;
71	void *start, *end;
72	size_t size;
73	int fd;
74
75	if (vdso_file->found)
76		return vdso_file->temp_file_name;
77
78	if (vdso_file->error || find_vdso_map(&start, &end))
79		return NULL;
80
81	size = end - start;
82
83	buf = memdup(start, size);
84	if (!buf)
85		return NULL;
86
87	fd = mkstemp(vdso_file->temp_file_name);
88	if (fd < 0)
89		goto out;
90
91	if (size == (size_t) write(fd, buf, size))
92		vdso = vdso_file->temp_file_name;
93
94	close(fd);
95
96 out:
97	free(buf);
98
99	vdso_file->found = (vdso != NULL);
100	vdso_file->error = !vdso_file->found;
101	return vdso;
102}
103
104void vdso__exit(struct machine *machine)
105{
106	struct vdso_info *vdso_info = machine->vdso_info;
107
108	if (!vdso_info)
109		return;
110
111	if (vdso_info->vdso.found)
112		unlink(vdso_info->vdso.temp_file_name);
113#if BITS_PER_LONG == 64
114	if (vdso_info->vdso32.found)
115		unlink(vdso_info->vdso32.temp_file_name);
116	if (vdso_info->vdsox32.found)
117		unlink(vdso_info->vdsox32.temp_file_name);
118#endif
119
120	zfree(&machine->vdso_info);
121}
122
123static struct dso *vdso__new(struct machine *machine, const char *short_name,
124			     const char *long_name)
125{
126	struct dso *dso;
127
128	dso = dso__new(short_name);
129	if (dso != NULL) {
130		dsos__add(&machine->user_dsos, dso);
131		dso__set_long_name(dso, long_name, false);
132	}
133
134	return dso;
135}
136
137#if BITS_PER_LONG == 64
138
139static enum dso_type machine__thread_dso_type(struct machine *machine,
140					      struct thread *thread)
141{
142	enum dso_type dso_type = DSO__TYPE_UNKNOWN;
143	struct map *map;
144	struct dso *dso;
145
146	map = map_groups__first(thread->mg, MAP__FUNCTION);
147	for (; map ; map = map_groups__next(map)) {
148		dso = map->dso;
149		if (!dso || dso->long_name[0] != '/')
150			continue;
151		dso_type = dso__type(dso, machine);
152		if (dso_type != DSO__TYPE_UNKNOWN)
153			break;
154	}
155
156	return dso_type;
157}
158
159static int vdso__do_copy_compat(FILE *f, int fd)
160{
161	char buf[4096];
162	size_t count;
163
164	while (1) {
165		count = fread(buf, 1, sizeof(buf), f);
166		if (ferror(f))
167			return -errno;
168		if (feof(f))
169			break;
170		if (count && writen(fd, buf, count) != (ssize_t)count)
171			return -errno;
172	}
173
174	return 0;
175}
176
177static int vdso__copy_compat(const char *prog, int fd)
178{
179	FILE *f;
180	int err;
181
182	f = popen(prog, "r");
183	if (!f)
184		return -errno;
185
186	err = vdso__do_copy_compat(f, fd);
187
188	if (pclose(f) == -1)
189		return -errno;
190
191	return err;
192}
193
194static int vdso__create_compat_file(const char *prog, char *temp_name)
195{
196	int fd, err;
197
198	fd = mkstemp(temp_name);
199	if (fd < 0)
200		return -errno;
201
202	err = vdso__copy_compat(prog, fd);
203
204	if (close(fd) == -1)
205		return -errno;
206
207	return err;
208}
209
210static const char *vdso__get_compat_file(struct vdso_file *vdso_file)
211{
212	int err;
213
214	if (vdso_file->found)
215		return vdso_file->temp_file_name;
216
217	if (vdso_file->error)
218		return NULL;
219
220	err = vdso__create_compat_file(vdso_file->read_prog,
221				       vdso_file->temp_file_name);
222	if (err) {
223		pr_err("%s failed, error %d\n", vdso_file->read_prog, err);
224		vdso_file->error = true;
225		return NULL;
226	}
227
228	vdso_file->found = true;
229
230	return vdso_file->temp_file_name;
231}
232
233static struct dso *vdso__findnew_compat(struct machine *machine,
234					struct vdso_file *vdso_file)
235{
236	const char *file_name;
237	struct dso *dso;
238
239	dso = dsos__find(&machine->user_dsos, vdso_file->dso_name, true);
240	if (dso)
241		return dso;
242
243	file_name = vdso__get_compat_file(vdso_file);
244	if (!file_name)
245		return NULL;
246
247	return vdso__new(machine, vdso_file->dso_name, file_name);
248}
249
250static int vdso__dso_findnew_compat(struct machine *machine,
251				    struct thread *thread,
252				    struct vdso_info *vdso_info,
253				    struct dso **dso)
254{
255	enum dso_type dso_type;
256
257	dso_type = machine__thread_dso_type(machine, thread);
258
259#ifndef HAVE_PERF_READ_VDSO32
260	if (dso_type == DSO__TYPE_32BIT)
261		return 0;
262#endif
263#ifndef HAVE_PERF_READ_VDSOX32
264	if (dso_type == DSO__TYPE_X32BIT)
265		return 0;
266#endif
267
268	switch (dso_type) {
269	case DSO__TYPE_32BIT:
270		*dso = vdso__findnew_compat(machine, &vdso_info->vdso32);
271		return 1;
272	case DSO__TYPE_X32BIT:
273		*dso = vdso__findnew_compat(machine, &vdso_info->vdsox32);
274		return 1;
275	case DSO__TYPE_UNKNOWN:
276	case DSO__TYPE_64BIT:
277	default:
278		return 0;
279	}
280}
281
282#endif
283
284struct dso *vdso__dso_findnew(struct machine *machine,
285			      struct thread *thread __maybe_unused)
286{
287	struct vdso_info *vdso_info;
288	struct dso *dso;
289
290	if (!machine->vdso_info)
291		machine->vdso_info = vdso_info__new();
292
293	vdso_info = machine->vdso_info;
294	if (!vdso_info)
295		return NULL;
296
297#if BITS_PER_LONG == 64
298	if (vdso__dso_findnew_compat(machine, thread, vdso_info, &dso))
299		return dso;
300#endif
301
302	dso = dsos__find(&machine->user_dsos, DSO__NAME_VDSO, true);
303	if (!dso) {
304		char *file;
305
306		file = get_file(&vdso_info->vdso);
307		if (!file)
308			return NULL;
309
310		dso = vdso__new(machine, DSO__NAME_VDSO, file);
311	}
312
313	return dso;
314}
315
316bool dso__is_vdso(struct dso *dso)
317{
318	return !strcmp(dso->short_name, DSO__NAME_VDSO) ||
319	       !strcmp(dso->short_name, DSO__NAME_VDSO32) ||
320	       !strcmp(dso->short_name, DSO__NAME_VDSOX32);
321}
322