GNU Linux-libre 4.19.211-gnu1
[releases.git] / tools / perf / util / vdso.c
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
28 struct 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
36 struct 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
44 static 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
68 static 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
105 void 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
124 static 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
138 static 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 = map_groups__first(thread->mg);
143
144         for (; map ; map = map_groups__next(map)) {
145                 struct dso *dso = map->dso;
146                 if (!dso || dso->long_name[0] != '/')
147                         continue;
148                 dso_type = dso__type(dso, machine);
149                 if (dso_type != DSO__TYPE_UNKNOWN)
150                         break;
151         }
152
153         return dso_type;
154 }
155
156 #if BITS_PER_LONG == 64
157
158 static int vdso__do_copy_compat(FILE *f, int fd)
159 {
160         char buf[4096];
161         size_t count;
162
163         while (1) {
164                 count = fread(buf, 1, sizeof(buf), f);
165                 if (ferror(f))
166                         return -errno;
167                 if (feof(f))
168                         break;
169                 if (count && writen(fd, buf, count) != (ssize_t)count)
170                         return -errno;
171         }
172
173         return 0;
174 }
175
176 static int vdso__copy_compat(const char *prog, int fd)
177 {
178         FILE *f;
179         int err;
180
181         f = popen(prog, "r");
182         if (!f)
183                 return -errno;
184
185         err = vdso__do_copy_compat(f, fd);
186
187         if (pclose(f) == -1)
188                 return -errno;
189
190         return err;
191 }
192
193 static int vdso__create_compat_file(const char *prog, char *temp_name)
194 {
195         int fd, err;
196
197         fd = mkstemp(temp_name);
198         if (fd < 0)
199                 return -errno;
200
201         err = vdso__copy_compat(prog, fd);
202
203         if (close(fd) == -1)
204                 return -errno;
205
206         return err;
207 }
208
209 static const char *vdso__get_compat_file(struct vdso_file *vdso_file)
210 {
211         int err;
212
213         if (vdso_file->found)
214                 return vdso_file->temp_file_name;
215
216         if (vdso_file->error)
217                 return NULL;
218
219         err = vdso__create_compat_file(vdso_file->read_prog,
220                                        vdso_file->temp_file_name);
221         if (err) {
222                 pr_err("%s failed, error %d\n", vdso_file->read_prog, err);
223                 vdso_file->error = true;
224                 return NULL;
225         }
226
227         vdso_file->found = true;
228
229         return vdso_file->temp_file_name;
230 }
231
232 static struct dso *__machine__findnew_compat(struct machine *machine,
233                                              struct vdso_file *vdso_file)
234 {
235         const char *file_name;
236         struct dso *dso;
237
238         dso = __dsos__find(&machine->dsos, vdso_file->dso_name, true);
239         if (dso)
240                 goto out;
241
242         file_name = vdso__get_compat_file(vdso_file);
243         if (!file_name)
244                 goto out;
245
246         dso = __machine__addnew_vdso(machine, vdso_file->dso_name, file_name);
247 out:
248         return dso;
249 }
250
251 static int __machine__findnew_vdso_compat(struct machine *machine,
252                                           struct thread *thread,
253                                           struct vdso_info *vdso_info,
254                                           struct dso **dso)
255 {
256         enum dso_type dso_type;
257
258         dso_type = machine__thread_dso_type(machine, thread);
259
260 #ifndef HAVE_PERF_READ_VDSO32
261         if (dso_type == DSO__TYPE_32BIT)
262                 return 0;
263 #endif
264 #ifndef HAVE_PERF_READ_VDSOX32
265         if (dso_type == DSO__TYPE_X32BIT)
266                 return 0;
267 #endif
268
269         switch (dso_type) {
270         case DSO__TYPE_32BIT:
271                 *dso = __machine__findnew_compat(machine, &vdso_info->vdso32);
272                 return 1;
273         case DSO__TYPE_X32BIT:
274                 *dso = __machine__findnew_compat(machine, &vdso_info->vdsox32);
275                 return 1;
276         case DSO__TYPE_UNKNOWN:
277         case DSO__TYPE_64BIT:
278         default:
279                 return 0;
280         }
281 }
282
283 #endif
284
285 static struct dso *machine__find_vdso(struct machine *machine,
286                                       struct thread *thread)
287 {
288         struct dso *dso = NULL;
289         enum dso_type dso_type;
290
291         dso_type = machine__thread_dso_type(machine, thread);
292         switch (dso_type) {
293         case DSO__TYPE_32BIT:
294                 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO32, true);
295                 if (!dso) {
296                         dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO,
297                                            true);
298                         if (dso && dso_type != dso__type(dso, machine))
299                                 dso = NULL;
300                 }
301                 break;
302         case DSO__TYPE_X32BIT:
303                 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSOX32, true);
304                 break;
305         case DSO__TYPE_64BIT:
306         case DSO__TYPE_UNKNOWN:
307         default:
308                 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
309                 break;
310         }
311
312         return dso;
313 }
314
315 struct dso *machine__findnew_vdso(struct machine *machine,
316                                   struct thread *thread)
317 {
318         struct vdso_info *vdso_info;
319         struct dso *dso = NULL;
320
321         down_write(&machine->dsos.lock);
322         if (!machine->vdso_info)
323                 machine->vdso_info = vdso_info__new();
324
325         vdso_info = machine->vdso_info;
326         if (!vdso_info)
327                 goto out_unlock;
328
329         dso = machine__find_vdso(machine, thread);
330         if (dso)
331                 goto out_unlock;
332
333 #if BITS_PER_LONG == 64
334         if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso))
335                 goto out_unlock;
336 #endif
337
338         dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
339         if (!dso) {
340                 char *file;
341
342                 file = get_file(&vdso_info->vdso);
343                 if (file)
344                         dso = __machine__addnew_vdso(machine, DSO__NAME_VDSO, file);
345         }
346
347 out_unlock:
348         dso__get(dso);
349         up_write(&machine->dsos.lock);
350         return dso;
351 }
352
353 bool dso__is_vdso(struct dso *dso)
354 {
355         return !strcmp(dso->short_name, DSO__NAME_VDSO) ||
356                !strcmp(dso->short_name, DSO__NAME_VDSO32) ||
357                !strcmp(dso->short_name, DSO__NAME_VDSOX32);
358 }