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 "dso.h"
14#include <internal/lib.h>
15#include "map.h"
16#include "symbol.h"
17#include "machine.h"
18#include "thread.h"
19#include "linux/string.h"
20#include <linux/zalloc.h>
21#include "debug.h"
22
23/*
24 * Include definition of find_map() also used in perf-read-vdso.c for
25 * building perf-read-vdso32 and perf-read-vdsox32.
26 */
27#include "find-map.c"
28
29#define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX"
30
31struct vdso_file {
32 bool found;
33 bool error;
34 char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)];
35 const char *dso_name;
36 const char *read_prog;
37};
38
39struct vdso_info {
40 struct vdso_file vdso;
41#if BITS_PER_LONG == 64
42 struct vdso_file vdso32;
43 struct vdso_file vdsox32;
44#endif
45};
46
47static struct vdso_info *vdso_info__new(void)
48{
49 static const struct vdso_info vdso_info_init = {
50 .vdso = {
51 .temp_file_name = VDSO__TEMP_FILE_NAME,
52 .dso_name = DSO__NAME_VDSO,
53 },
54#if BITS_PER_LONG == 64
55 .vdso32 = {
56 .temp_file_name = VDSO__TEMP_FILE_NAME,
57 .dso_name = DSO__NAME_VDSO32,
58 .read_prog = "perf-read-vdso32",
59 },
60 .vdsox32 = {
61 .temp_file_name = VDSO__TEMP_FILE_NAME,
62 .dso_name = DSO__NAME_VDSOX32,
63 .read_prog = "perf-read-vdsox32",
64 },
65#endif
66 };
67
68 return memdup(&vdso_info_init, sizeof(vdso_info_init));
69}
70
71static char *get_file(struct vdso_file *vdso_file)
72{
73 char *vdso = NULL;
74 char *buf = NULL;
75 void *start, *end;
76 size_t size;
77 int fd;
78
79 if (vdso_file->found)
80 return vdso_file->temp_file_name;
81
82 if (vdso_file->error || find_map(start: &start, end: &end, VDSO__MAP_NAME))
83 return NULL;
84
85 size = end - start;
86
87 buf = memdup(start, size);
88 if (!buf)
89 return NULL;
90
91 fd = mkstemp(vdso_file->temp_file_name);
92 if (fd < 0)
93 goto out;
94
95 if (size == (size_t) write(fd, buf, size))
96 vdso = vdso_file->temp_file_name;
97
98 close(fd);
99
100 out:
101 free(buf);
102
103 vdso_file->found = (vdso != NULL);
104 vdso_file->error = !vdso_file->found;
105 return vdso;
106}
107
108void machine__exit_vdso(struct machine *machine)
109{
110 struct vdso_info *vdso_info = machine->vdso_info;
111
112 if (!vdso_info)
113 return;
114
115 if (vdso_info->vdso.found)
116 unlink(vdso_info->vdso.temp_file_name);
117#if BITS_PER_LONG == 64
118 if (vdso_info->vdso32.found)
119 unlink(vdso_info->vdso32.temp_file_name);
120 if (vdso_info->vdsox32.found)
121 unlink(vdso_info->vdsox32.temp_file_name);
122#endif
123
124 zfree(&machine->vdso_info);
125}
126
127static struct dso *__machine__addnew_vdso(struct machine *machine, const char *short_name,
128 const char *long_name)
129{
130 struct dso *dso;
131
132 dso = dso__new(name: short_name);
133 if (dso != NULL) {
134 __dsos__add(dsos: &machine->dsos, dso);
135 dso__set_long_name(dso, name: long_name, name_allocated: false);
136 }
137
138 return dso;
139}
140
141struct machine__thread_dso_type_maps_cb_args {
142 struct machine *machine;
143 enum dso_type dso_type;
144};
145
146static int machine__thread_dso_type_maps_cb(struct map *map, void *data)
147{
148 struct machine__thread_dso_type_maps_cb_args *args = data;
149 struct dso *dso = map__dso(map);
150
151 if (!dso || dso__long_name(dso)[0] != '/')
152 return 0;
153
154 args->dso_type = dso__type(dso, machine: args->machine);
155 return (args->dso_type != DSO__TYPE_UNKNOWN) ? 1 : 0;
156}
157
158static enum dso_type machine__thread_dso_type(struct machine *machine,
159 struct thread *thread)
160{
161 struct machine__thread_dso_type_maps_cb_args args = {
162 .machine = machine,
163 .dso_type = DSO__TYPE_UNKNOWN,
164 };
165
166 maps__for_each_map(maps: thread__maps(thread), cb: machine__thread_dso_type_maps_cb, data: &args);
167
168 return args.dso_type;
169}
170
171#if BITS_PER_LONG == 64
172
173static int vdso__do_copy_compat(FILE *f, int fd)
174{
175 char buf[4096];
176 size_t count;
177
178 while (1) {
179 count = fread(buf, 1, sizeof(buf), f);
180 if (ferror(f))
181 return -errno;
182 if (feof(f))
183 break;
184 if (count && writen(fd, buf, count) != (ssize_t)count)
185 return -errno;
186 }
187
188 return 0;
189}
190
191static int vdso__copy_compat(const char *prog, int fd)
192{
193 FILE *f;
194 int err;
195
196 f = popen(prog, "r");
197 if (!f)
198 return -errno;
199
200 err = vdso__do_copy_compat(f, fd);
201
202 if (pclose(f) == -1)
203 return -errno;
204
205 return err;
206}
207
208static int vdso__create_compat_file(const char *prog, char *temp_name)
209{
210 int fd, err;
211
212 fd = mkstemp(temp_name);
213 if (fd < 0)
214 return -errno;
215
216 err = vdso__copy_compat(prog, fd);
217
218 if (close(fd) == -1)
219 return -errno;
220
221 return err;
222}
223
224static const char *vdso__get_compat_file(struct vdso_file *vdso_file)
225{
226 int err;
227
228 if (vdso_file->found)
229 return vdso_file->temp_file_name;
230
231 if (vdso_file->error)
232 return NULL;
233
234 err = vdso__create_compat_file(prog: vdso_file->read_prog,
235 temp_name: vdso_file->temp_file_name);
236 if (err) {
237 pr_err("%s failed, error %d\n", vdso_file->read_prog, err);
238 vdso_file->error = true;
239 return NULL;
240 }
241
242 vdso_file->found = true;
243
244 return vdso_file->temp_file_name;
245}
246
247static struct dso *__machine__findnew_compat(struct machine *machine,
248 struct vdso_file *vdso_file)
249{
250 const char *file_name;
251 struct dso *dso;
252
253 dso = dsos__find(dsos: &machine->dsos, name: vdso_file->dso_name, cmp_short: true);
254 if (dso)
255 return dso;
256
257 file_name = vdso__get_compat_file(vdso_file);
258 if (!file_name)
259 return NULL;
260
261 return __machine__addnew_vdso(machine, short_name: vdso_file->dso_name, long_name: file_name);
262}
263
264static int __machine__findnew_vdso_compat(struct machine *machine,
265 struct thread *thread,
266 struct vdso_info *vdso_info,
267 struct dso **dso)
268{
269 enum dso_type dso_type;
270
271 dso_type = machine__thread_dso_type(machine, thread);
272
273#ifndef HAVE_PERF_READ_VDSO32
274 if (dso_type == DSO__TYPE_32BIT)
275 return 0;
276#endif
277#ifndef HAVE_PERF_READ_VDSOX32
278 if (dso_type == DSO__TYPE_X32BIT)
279 return 0;
280#endif
281
282 switch (dso_type) {
283 case DSO__TYPE_32BIT:
284 *dso = __machine__findnew_compat(machine, vdso_file: &vdso_info->vdso32);
285 return 1;
286 case DSO__TYPE_X32BIT:
287 *dso = __machine__findnew_compat(machine, vdso_file: &vdso_info->vdsox32);
288 return 1;
289 case DSO__TYPE_UNKNOWN:
290 case DSO__TYPE_64BIT:
291 default:
292 return 0;
293 }
294}
295
296#endif
297
298static struct dso *machine__find_vdso(struct machine *machine,
299 struct thread *thread)
300{
301 struct dso *dso = NULL;
302 enum dso_type dso_type;
303
304 dso_type = machine__thread_dso_type(machine, thread);
305 switch (dso_type) {
306 case DSO__TYPE_32BIT:
307 dso = dsos__find(dsos: &machine->dsos, DSO__NAME_VDSO32, cmp_short: true);
308 if (!dso) {
309 dso = dsos__find(dsos: &machine->dsos, DSO__NAME_VDSO,
310 cmp_short: true);
311 if (dso && dso_type != dso__type(dso, machine)) {
312 dso__put(dso);
313 dso = NULL;
314 }
315 }
316 break;
317 case DSO__TYPE_X32BIT:
318 dso = dsos__find(dsos: &machine->dsos, DSO__NAME_VDSOX32, cmp_short: true);
319 break;
320 case DSO__TYPE_64BIT:
321 case DSO__TYPE_UNKNOWN:
322 default:
323 dso = dsos__find(dsos: &machine->dsos, DSO__NAME_VDSO, cmp_short: true);
324 break;
325 }
326
327 return dso;
328}
329
330struct dso *machine__findnew_vdso(struct machine *machine,
331 struct thread *thread)
332{
333 struct vdso_info *vdso_info;
334 struct dso *dso = NULL;
335 char *file;
336
337 if (!machine->vdso_info)
338 machine->vdso_info = vdso_info__new();
339
340 vdso_info = machine->vdso_info;
341 if (!vdso_info)
342 return NULL;
343
344 dso = machine__find_vdso(machine, thread);
345 if (dso)
346 return dso;
347
348#if BITS_PER_LONG == 64
349 if (__machine__findnew_vdso_compat(machine, thread, vdso_info, dso: &dso))
350 return dso;
351#endif
352
353 dso = dsos__find(dsos: &machine->dsos, DSO__NAME_VDSO, cmp_short: true);
354 if (dso)
355 return dso;
356
357 file = get_file(f: &vdso_info->vdso);
358 if (!file)
359 return NULL;
360
361 return __machine__addnew_vdso(machine, DSO__NAME_VDSO, long_name: file);
362}
363
364bool dso__is_vdso(struct dso *dso)
365{
366 return !strcmp(dso__short_name(dso), DSO__NAME_VDSO) ||
367 !strcmp(dso__short_name(dso), DSO__NAME_VDSO32) ||
368 !strcmp(dso__short_name(dso), DSO__NAME_VDSOX32);
369}
370

source code of linux/tools/perf/util/vdso.c