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