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 /* Put dso here because __dsos_add already got it */
137 dso__put(dso);
138 }
139
140 return dso;
141 }
142
machine__thread_dso_type(struct machine * machine,struct thread * thread)143 static enum dso_type machine__thread_dso_type(struct machine *machine,
144 struct thread *thread)
145 {
146 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
147 struct map *map;
148
149 maps__for_each_entry(thread->maps, map) {
150 struct dso *dso = map->dso;
151 if (!dso || dso->long_name[0] != '/')
152 continue;
153 dso_type = dso__type(dso, machine);
154 if (dso_type != DSO__TYPE_UNKNOWN)
155 break;
156 }
157
158 return dso_type;
159 }
160
161 #if BITS_PER_LONG == 64
162
vdso__do_copy_compat(FILE * f,int fd)163 static int vdso__do_copy_compat(FILE *f, int fd)
164 {
165 char buf[4096];
166 size_t count;
167
168 while (1) {
169 count = fread(buf, 1, sizeof(buf), f);
170 if (ferror(f))
171 return -errno;
172 if (feof(f))
173 break;
174 if (count && writen(fd, buf, count) != (ssize_t)count)
175 return -errno;
176 }
177
178 return 0;
179 }
180
vdso__copy_compat(const char * prog,int fd)181 static int vdso__copy_compat(const char *prog, int fd)
182 {
183 FILE *f;
184 int err;
185
186 f = popen(prog, "r");
187 if (!f)
188 return -errno;
189
190 err = vdso__do_copy_compat(f, fd);
191
192 if (pclose(f) == -1)
193 return -errno;
194
195 return err;
196 }
197
vdso__create_compat_file(const char * prog,char * temp_name)198 static int vdso__create_compat_file(const char *prog, char *temp_name)
199 {
200 int fd, err;
201
202 fd = mkstemp(temp_name);
203 if (fd < 0)
204 return -errno;
205
206 err = vdso__copy_compat(prog, fd);
207
208 if (close(fd) == -1)
209 return -errno;
210
211 return err;
212 }
213
vdso__get_compat_file(struct vdso_file * vdso_file)214 static const char *vdso__get_compat_file(struct vdso_file *vdso_file)
215 {
216 int err;
217
218 if (vdso_file->found)
219 return vdso_file->temp_file_name;
220
221 if (vdso_file->error)
222 return NULL;
223
224 err = vdso__create_compat_file(vdso_file->read_prog,
225 vdso_file->temp_file_name);
226 if (err) {
227 pr_err("%s failed, error %d\n", vdso_file->read_prog, err);
228 vdso_file->error = true;
229 return NULL;
230 }
231
232 vdso_file->found = true;
233
234 return vdso_file->temp_file_name;
235 }
236
__machine__findnew_compat(struct machine * machine,struct vdso_file * vdso_file)237 static struct dso *__machine__findnew_compat(struct machine *machine,
238 struct vdso_file *vdso_file)
239 {
240 const char *file_name;
241 struct dso *dso;
242
243 dso = __dsos__find(&machine->dsos, vdso_file->dso_name, true);
244 if (dso)
245 goto out;
246
247 file_name = vdso__get_compat_file(vdso_file);
248 if (!file_name)
249 goto out;
250
251 dso = __machine__addnew_vdso(machine, vdso_file->dso_name, file_name);
252 out:
253 return dso;
254 }
255
__machine__findnew_vdso_compat(struct machine * machine,struct thread * thread,struct vdso_info * vdso_info,struct dso ** dso)256 static int __machine__findnew_vdso_compat(struct machine *machine,
257 struct thread *thread,
258 struct vdso_info *vdso_info,
259 struct dso **dso)
260 {
261 enum dso_type dso_type;
262
263 dso_type = machine__thread_dso_type(machine, thread);
264
265 #ifndef HAVE_PERF_READ_VDSO32
266 if (dso_type == DSO__TYPE_32BIT)
267 return 0;
268 #endif
269 #ifndef HAVE_PERF_READ_VDSOX32
270 if (dso_type == DSO__TYPE_X32BIT)
271 return 0;
272 #endif
273
274 switch (dso_type) {
275 case DSO__TYPE_32BIT:
276 *dso = __machine__findnew_compat(machine, &vdso_info->vdso32);
277 return 1;
278 case DSO__TYPE_X32BIT:
279 *dso = __machine__findnew_compat(machine, &vdso_info->vdsox32);
280 return 1;
281 case DSO__TYPE_UNKNOWN:
282 case DSO__TYPE_64BIT:
283 default:
284 return 0;
285 }
286 }
287
288 #endif
289
machine__find_vdso(struct machine * machine,struct thread * thread)290 static struct dso *machine__find_vdso(struct machine *machine,
291 struct thread *thread)
292 {
293 struct dso *dso = NULL;
294 enum dso_type dso_type;
295
296 dso_type = machine__thread_dso_type(machine, thread);
297 switch (dso_type) {
298 case DSO__TYPE_32BIT:
299 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO32, true);
300 if (!dso) {
301 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO,
302 true);
303 if (dso && dso_type != dso__type(dso, machine))
304 dso = NULL;
305 }
306 break;
307 case DSO__TYPE_X32BIT:
308 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSOX32, true);
309 break;
310 case DSO__TYPE_64BIT:
311 case DSO__TYPE_UNKNOWN:
312 default:
313 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
314 break;
315 }
316
317 return dso;
318 }
319
machine__findnew_vdso(struct machine * machine,struct thread * thread)320 struct dso *machine__findnew_vdso(struct machine *machine,
321 struct thread *thread)
322 {
323 struct vdso_info *vdso_info;
324 struct dso *dso = NULL;
325
326 down_write(&machine->dsos.lock);
327 if (!machine->vdso_info)
328 machine->vdso_info = vdso_info__new();
329
330 vdso_info = machine->vdso_info;
331 if (!vdso_info)
332 goto out_unlock;
333
334 dso = machine__find_vdso(machine, thread);
335 if (dso)
336 goto out_unlock;
337
338 #if BITS_PER_LONG == 64
339 if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso))
340 goto out_unlock;
341 #endif
342
343 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
344 if (!dso) {
345 char *file;
346
347 file = get_file(&vdso_info->vdso);
348 if (file)
349 dso = __machine__addnew_vdso(machine, DSO__NAME_VDSO, file);
350 }
351
352 out_unlock:
353 dso__get(dso);
354 up_write(&machine->dsos.lock);
355 return dso;
356 }
357
dso__is_vdso(struct dso * dso)358 bool dso__is_vdso(struct dso *dso)
359 {
360 return !strcmp(dso->short_name, DSO__NAME_VDSO) ||
361 !strcmp(dso->short_name, DSO__NAME_VDSO32) ||
362 !strcmp(dso->short_name, DSO__NAME_VDSOX32);
363 }
364
