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1// SPDX-License-Identifier: GPL-2.0
2#include <errno.h>
3#include <unistd.h>
4#include <stdio.h>
5#include <string.h>
6#include <sys/types.h>
7#include <sys/stat.h>
8#include <fcntl.h>
9#include <stdlib.h>
10#include <linux/kernel.h>
11
12#include "vdso.h"
13#include "util.h"
14#include "symbol.h"
15#include "machine.h"
16#include "thread.h"
17#include "linux/string.h"
18#include "debug.h"
19
20/*
21 * Include definition of find_vdso_map() also used in perf-read-vdso.c for
22 * building perf-read-vdso32 and perf-read-vdsox32.
23 */
24#include "find-vdso-map.c"
25
26#define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX"
27
28struct vdso_file {
29 bool found;
30 bool error;
31 char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)];
32 const char *dso_name;
33 const char *read_prog;
34};
35
36struct vdso_info {
37 struct vdso_file vdso;
38#if BITS_PER_LONG == 64
39 struct vdso_file vdso32;
40 struct vdso_file vdsox32;
41#endif
42};
43
44static struct vdso_info *vdso_info__new(void)
45{
46 static const struct vdso_info vdso_info_init = {
47 .vdso = {
48 .temp_file_name = VDSO__TEMP_FILE_NAME,
49 .dso_name = DSO__NAME_VDSO,
50 },
51#if BITS_PER_LONG == 64
52 .vdso32 = {
53 .temp_file_name = VDSO__TEMP_FILE_NAME,
54 .dso_name = DSO__NAME_VDSO32,
55 .read_prog = "perf-read-vdso32",
56 },
57 .vdsox32 = {
58 .temp_file_name = VDSO__TEMP_FILE_NAME,
59 .dso_name = DSO__NAME_VDSOX32,
60 .read_prog = "perf-read-vdsox32",
61 },
62#endif
63 };
64
65 return memdup(&vdso_info_init, sizeof(vdso_info_init));
66}
67
68static char *get_file(struct vdso_file *vdso_file)
69{
70 char *vdso = NULL;
71 char *buf = NULL;
72 void *start, *end;
73 size_t size;
74 int fd;
75
76 if (vdso_file->found)
77 return vdso_file->temp_file_name;
78
79 if (vdso_file->error || find_vdso_map(&start, &end))
80 return NULL;
81
82 size = end - start;
83
84 buf = memdup(start, size);
85 if (!buf)
86 return NULL;
87
88 fd = mkstemp(vdso_file->temp_file_name);
89 if (fd < 0)
90 goto out;
91
92 if (size == (size_t) write(fd, buf, size))
93 vdso = vdso_file->temp_file_name;
94
95 close(fd);
96
97 out:
98 free(buf);
99
100 vdso_file->found = (vdso != NULL);
101 vdso_file->error = !vdso_file->found;
102 return vdso;
103}
104
105void machine__exit_vdso(struct machine *machine)
106{
107 struct vdso_info *vdso_info = machine->vdso_info;
108
109 if (!vdso_info)
110 return;
111
112 if (vdso_info->vdso.found)
113 unlink(vdso_info->vdso.temp_file_name);
114#if BITS_PER_LONG == 64
115 if (vdso_info->vdso32.found)
116 unlink(vdso_info->vdso32.temp_file_name);
117 if (vdso_info->vdsox32.found)
118 unlink(vdso_info->vdsox32.temp_file_name);
119#endif
120
121 zfree(&machine->vdso_info);
122}
123
124static struct dso *__machine__addnew_vdso(struct machine *machine, const char *short_name,
125 const char *long_name)
126{
127 struct dso *dso;
128
129 dso = dso__new(short_name);
130 if (dso != NULL) {
131 __dsos__add(&machine->dsos, dso);
132 dso__set_long_name(dso, long_name, false);
133 }
134
135 return dso;
136}
137
138static enum dso_type machine__thread_dso_type(struct machine *machine,
139 struct thread *thread)
140{
141 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
142 struct map *map;
143 struct dso *dso;
144
145 map = map_groups__first(thread->mg, MAP__FUNCTION);
146 for (; map ; map = map_groups__next(map)) {
147 dso = map->dso;
148 if (!dso || dso->long_name[0] != '/')
149 continue;
150 dso_type = dso__type(dso, machine);
151 if (dso_type != DSO__TYPE_UNKNOWN)
152 break;
153 }
154
155 return dso_type;
156}
157
158#if BITS_PER_LONG == 64
159
160static int vdso__do_copy_compat(FILE *f, int fd)
161{
162 char buf[4096];
163 size_t count;
164
165 while (1) {
166 count = fread(buf, 1, sizeof(buf), f);
167 if (ferror(f))
168 return -errno;
169 if (feof(f))
170 break;
171 if (count && writen(fd, buf, count) != (ssize_t)count)
172 return -errno;
173 }
174
175 return 0;
176}
177
178static int vdso__copy_compat(const char *prog, int fd)
179{
180 FILE *f;
181 int err;
182
183 f = popen(prog, "r");
184 if (!f)
185 return -errno;
186
187 err = vdso__do_copy_compat(f, fd);
188
189 if (pclose(f) == -1)
190 return -errno;
191
192 return err;
193}
194
195static int vdso__create_compat_file(const char *prog, char *temp_name)
196{
197 int fd, err;
198
199 fd = mkstemp(temp_name);
200 if (fd < 0)
201 return -errno;
202
203 err = vdso__copy_compat(prog, fd);
204
205 if (close(fd) == -1)
206 return -errno;
207
208 return err;
209}
210
211static const char *vdso__get_compat_file(struct vdso_file *vdso_file)
212{
213 int err;
214
215 if (vdso_file->found)
216 return vdso_file->temp_file_name;
217
218 if (vdso_file->error)
219 return NULL;
220
221 err = vdso__create_compat_file(vdso_file->read_prog,
222 vdso_file->temp_file_name);
223 if (err) {
224 pr_err("%s failed, error %d\n", vdso_file->read_prog, err);
225 vdso_file->error = true;
226 return NULL;
227 }
228
229 vdso_file->found = true;
230
231 return vdso_file->temp_file_name;
232}
233
234static struct dso *__machine__findnew_compat(struct machine *machine,
235 struct vdso_file *vdso_file)
236{
237 const char *file_name;
238 struct dso *dso;
239
240 dso = __dsos__find(&machine->dsos, vdso_file->dso_name, true);
241 if (dso)
242 goto out;
243
244 file_name = vdso__get_compat_file(vdso_file);
245 if (!file_name)
246 goto out;
247
248 dso = __machine__addnew_vdso(machine, vdso_file->dso_name, file_name);
249out:
250 return dso;
251}
252
253static int __machine__findnew_vdso_compat(struct machine *machine,
254 struct thread *thread,
255 struct vdso_info *vdso_info,
256 struct dso **dso)
257{
258 enum dso_type dso_type;
259
260 dso_type = machine__thread_dso_type(machine, thread);
261
262#ifndef HAVE_PERF_READ_VDSO32
263 if (dso_type == DSO__TYPE_32BIT)
264 return 0;
265#endif
266#ifndef HAVE_PERF_READ_VDSOX32
267 if (dso_type == DSO__TYPE_X32BIT)
268 return 0;
269#endif
270
271 switch (dso_type) {
272 case DSO__TYPE_32BIT:
273 *dso = __machine__findnew_compat(machine, &vdso_info->vdso32);
274 return 1;
275 case DSO__TYPE_X32BIT:
276 *dso = __machine__findnew_compat(machine, &vdso_info->vdsox32);
277 return 1;
278 case DSO__TYPE_UNKNOWN:
279 case DSO__TYPE_64BIT:
280 default:
281 return 0;
282 }
283}
284
285#endif
286
287static struct dso *machine__find_vdso(struct machine *machine,
288 struct thread *thread)
289{
290 struct dso *dso = NULL;
291 enum dso_type dso_type;
292
293 dso_type = machine__thread_dso_type(machine, thread);
294 switch (dso_type) {
295 case DSO__TYPE_32BIT:
296 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO32, true);
297 if (!dso) {
298 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO,
299 true);
300 if (dso && dso_type != dso__type(dso, machine))
301 dso = NULL;
302 }
303 break;
304 case DSO__TYPE_X32BIT:
305 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSOX32, true);
306 break;
307 case DSO__TYPE_64BIT:
308 case DSO__TYPE_UNKNOWN:
309 default:
310 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
311 break;
312 }
313
314 return dso;
315}
316
317struct dso *machine__findnew_vdso(struct machine *machine,
318 struct thread *thread)
319{
320 struct vdso_info *vdso_info;
321 struct dso *dso = NULL;
322
323 down_write(&machine->dsos.lock);
324 if (!machine->vdso_info)
325 machine->vdso_info = vdso_info__new();
326
327 vdso_info = machine->vdso_info;
328 if (!vdso_info)
329 goto out_unlock;
330
331 dso = machine__find_vdso(machine, thread);
332 if (dso)
333 goto out_unlock;
334
335#if BITS_PER_LONG == 64
336 if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso))
337 goto out_unlock;
338#endif
339
340 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
341 if (!dso) {
342 char *file;
343
344 file = get_file(&vdso_info->vdso);
345 if (file)
346 dso = __machine__addnew_vdso(machine, DSO__NAME_VDSO, file);
347 }
348
349out_unlock:
350 dso__get(dso);
351 up_write(&machine->dsos.lock);
352 return dso;
353}
354
355bool dso__is_vdso(struct dso *dso)
356{
357 return !strcmp(dso->short_name, DSO__NAME_VDSO) ||
358 !strcmp(dso->short_name, DSO__NAME_VDSO32) ||
359 !strcmp(dso->short_name, DSO__NAME_VDSOX32);
360}
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 "linux/string.h"
15
16static bool vdso_found;
17static char vdso_file[] = "/tmp/perf-vdso.so-XXXXXX";
18
19static int find_vdso_map(void **start, void **end)
20{
21 FILE *maps;
22 char line[128];
23 int found = 0;
24
25 maps = fopen("/proc/self/maps", "r");
26 if (!maps) {
27 pr_err("vdso: cannot open maps\n");
28 return -1;
29 }
30
31 while (!found && fgets(line, sizeof(line), maps)) {
32 int m = -1;
33
34 /* We care only about private r-x mappings. */
35 if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n",
36 start, end, &m))
37 continue;
38 if (m < 0)
39 continue;
40
41 if (!strncmp(&line[m], VDSO__MAP_NAME,
42 sizeof(VDSO__MAP_NAME) - 1))
43 found = 1;
44 }
45
46 fclose(maps);
47 return !found;
48}
49
50static char *get_file(void)
51{
52 char *vdso = NULL;
53 char *buf = NULL;
54 void *start, *end;
55 size_t size;
56 int fd;
57
58 if (vdso_found)
59 return vdso_file;
60
61 if (find_vdso_map(&start, &end))
62 return NULL;
63
64 size = end - start;
65
66 buf = memdup(start, size);
67 if (!buf)
68 return NULL;
69
70 fd = mkstemp(vdso_file);
71 if (fd < 0)
72 goto out;
73
74 if (size == (size_t) write(fd, buf, size))
75 vdso = vdso_file;
76
77 close(fd);
78
79 out:
80 free(buf);
81
82 vdso_found = (vdso != NULL);
83 return vdso;
84}
85
86void vdso__exit(void)
87{
88 if (vdso_found)
89 unlink(vdso_file);
90}
91
92struct dso *vdso__dso_findnew(struct list_head *head)
93{
94 struct dso *dso = dsos__find(head, VDSO__MAP_NAME, true);
95
96 if (!dso) {
97 char *file;
98
99 file = get_file();
100 if (!file)
101 return NULL;
102
103 dso = dso__new(VDSO__MAP_NAME);
104 if (dso != NULL) {
105 dsos__add(head, dso);
106 dso__set_long_name(dso, file, false);
107 }
108 }
109
110 return dso;
111}