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
31 struct 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
39 struct 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
vdso_info__new(void)47 static 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
get_file(struct vdso_file * vdso_file)71 static 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, &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
machine__exit_vdso(struct machine * machine)108 void 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
__machine__addnew_vdso(struct machine * machine,const char * short_name,const char * long_name)127 static 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(short_name);
133 if (dso != NULL) {
134 __dsos__add(&machine->dsos, dso);
135 dso__set_long_name(dso, long_name, false);
136 }
137
138 return dso;
139 }
140
machine__thread_dso_type(struct machine * machine,struct thread * thread)141 static enum dso_type machine__thread_dso_type(struct machine *machine,
142 struct thread *thread)
143 {
144 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
145 struct map *map;
146
147 maps__for_each_entry(thread->maps, map) {
148 struct dso *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
159 #if BITS_PER_LONG == 64
160
vdso__do_copy_compat(FILE * f,int fd)161 static int vdso__do_copy_compat(FILE *f, int fd)
162 {
163 char buf[4096];
164 size_t count;
165
166 while (1) {
167 count = fread(buf, 1, sizeof(buf), f);
168 if (ferror(f))
169 return -errno;
170 if (feof(f))
171 break;
172 if (count && writen(fd, buf, count) != (ssize_t)count)
173 return -errno;
174 }
175
176 return 0;
177 }
178
vdso__copy_compat(const char * prog,int fd)179 static int vdso__copy_compat(const char *prog, int fd)
180 {
181 FILE *f;
182 int err;
183
184 f = popen(prog, "r");
185 if (!f)
186 return -errno;
187
188 err = vdso__do_copy_compat(f, fd);
189
190 if (pclose(f) == -1)
191 return -errno;
192
193 return err;
194 }
195
vdso__create_compat_file(const char * prog,char * temp_name)196 static int vdso__create_compat_file(const char *prog, char *temp_name)
197 {
198 int fd, err;
199
200 fd = mkstemp(temp_name);
201 if (fd < 0)
202 return -errno;
203
204 err = vdso__copy_compat(prog, fd);
205
206 if (close(fd) == -1)
207 return -errno;
208
209 return err;
210 }
211
vdso__get_compat_file(struct vdso_file * vdso_file)212 static const char *vdso__get_compat_file(struct vdso_file *vdso_file)
213 {
214 int err;
215
216 if (vdso_file->found)
217 return vdso_file->temp_file_name;
218
219 if (vdso_file->error)
220 return NULL;
221
222 err = vdso__create_compat_file(vdso_file->read_prog,
223 vdso_file->temp_file_name);
224 if (err) {
225 pr_err("%s failed, error %d\n", vdso_file->read_prog, err);
226 vdso_file->error = true;
227 return NULL;
228 }
229
230 vdso_file->found = true;
231
232 return vdso_file->temp_file_name;
233 }
234
__machine__findnew_compat(struct machine * machine,struct vdso_file * vdso_file)235 static struct dso *__machine__findnew_compat(struct machine *machine,
236 struct vdso_file *vdso_file)
237 {
238 const char *file_name;
239 struct dso *dso;
240
241 dso = __dsos__find(&machine->dsos, vdso_file->dso_name, true);
242 if (dso)
243 goto out;
244
245 file_name = vdso__get_compat_file(vdso_file);
246 if (!file_name)
247 goto out;
248
249 dso = __machine__addnew_vdso(machine, vdso_file->dso_name, file_name);
250 out:
251 return dso;
252 }
253
__machine__findnew_vdso_compat(struct machine * machine,struct thread * thread,struct vdso_info * vdso_info,struct dso ** dso)254 static int __machine__findnew_vdso_compat(struct machine *machine,
255 struct thread *thread,
256 struct vdso_info *vdso_info,
257 struct dso **dso)
258 {
259 enum dso_type dso_type;
260
261 dso_type = machine__thread_dso_type(machine, thread);
262
263 #ifndef HAVE_PERF_READ_VDSO32
264 if (dso_type == DSO__TYPE_32BIT)
265 return 0;
266 #endif
267 #ifndef HAVE_PERF_READ_VDSOX32
268 if (dso_type == DSO__TYPE_X32BIT)
269 return 0;
270 #endif
271
272 switch (dso_type) {
273 case DSO__TYPE_32BIT:
274 *dso = __machine__findnew_compat(machine, &vdso_info->vdso32);
275 return 1;
276 case DSO__TYPE_X32BIT:
277 *dso = __machine__findnew_compat(machine, &vdso_info->vdsox32);
278 return 1;
279 case DSO__TYPE_UNKNOWN:
280 case DSO__TYPE_64BIT:
281 default:
282 return 0;
283 }
284 }
285
286 #endif
287
machine__find_vdso(struct machine * machine,struct thread * thread)288 static struct dso *machine__find_vdso(struct machine *machine,
289 struct thread *thread)
290 {
291 struct dso *dso = NULL;
292 enum dso_type dso_type;
293
294 dso_type = machine__thread_dso_type(machine, thread);
295 switch (dso_type) {
296 case DSO__TYPE_32BIT:
297 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO32, true);
298 if (!dso) {
299 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO,
300 true);
301 if (dso && dso_type != dso__type(dso, machine))
302 dso = NULL;
303 }
304 break;
305 case DSO__TYPE_X32BIT:
306 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSOX32, true);
307 break;
308 case DSO__TYPE_64BIT:
309 case DSO__TYPE_UNKNOWN:
310 default:
311 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
312 break;
313 }
314
315 return dso;
316 }
317
machine__findnew_vdso(struct machine * machine,struct thread * thread)318 struct dso *machine__findnew_vdso(struct machine *machine,
319 struct thread *thread)
320 {
321 struct vdso_info *vdso_info;
322 struct dso *dso = NULL;
323
324 down_write(&machine->dsos.lock);
325 if (!machine->vdso_info)
326 machine->vdso_info = vdso_info__new();
327
328 vdso_info = machine->vdso_info;
329 if (!vdso_info)
330 goto out_unlock;
331
332 dso = machine__find_vdso(machine, thread);
333 if (dso)
334 goto out_unlock;
335
336 #if BITS_PER_LONG == 64
337 if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso))
338 goto out_unlock;
339 #endif
340
341 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
342 if (!dso) {
343 char *file;
344
345 file = get_file(&vdso_info->vdso);
346 if (file)
347 dso = __machine__addnew_vdso(machine, DSO__NAME_VDSO, file);
348 }
349
350 out_unlock:
351 dso__get(dso);
352 up_write(&machine->dsos.lock);
353 return dso;
354 }
355
dso__is_vdso(struct dso * dso)356 bool dso__is_vdso(struct dso *dso)
357 {
358 return !strcmp(dso->short_name, DSO__NAME_VDSO) ||
359 !strcmp(dso->short_name, DSO__NAME_VDSO32) ||
360 !strcmp(dso->short_name, DSO__NAME_VDSOX32);
361 }
362
