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_rb_node *rb_node;
148
149 maps__for_each_entry(thread__maps(thread), rb_node) {
150 struct dso *dso = map__dso(rb_node->map);
151
152 if (!dso || dso->long_name[0] != '/')
153 continue;
154 dso_type = dso__type(dso, machine);
155 if (dso_type != DSO__TYPE_UNKNOWN)
156 break;
157 }
158
159 return dso_type;
160 }
161
162 #if BITS_PER_LONG == 64
163
vdso__do_copy_compat(FILE * f,int fd)164 static int vdso__do_copy_compat(FILE *f, int fd)
165 {
166 char buf[4096];
167 size_t count;
168
169 while (1) {
170 count = fread(buf, 1, sizeof(buf), f);
171 if (ferror(f))
172 return -errno;
173 if (feof(f))
174 break;
175 if (count && writen(fd, buf, count) != (ssize_t)count)
176 return -errno;
177 }
178
179 return 0;
180 }
181
vdso__copy_compat(const char * prog,int fd)182 static int vdso__copy_compat(const char *prog, int fd)
183 {
184 FILE *f;
185 int err;
186
187 f = popen(prog, "r");
188 if (!f)
189 return -errno;
190
191 err = vdso__do_copy_compat(f, fd);
192
193 if (pclose(f) == -1)
194 return -errno;
195
196 return err;
197 }
198
vdso__create_compat_file(const char * prog,char * temp_name)199 static int vdso__create_compat_file(const char *prog, char *temp_name)
200 {
201 int fd, err;
202
203 fd = mkstemp(temp_name);
204 if (fd < 0)
205 return -errno;
206
207 err = vdso__copy_compat(prog, fd);
208
209 if (close(fd) == -1)
210 return -errno;
211
212 return err;
213 }
214
vdso__get_compat_file(struct vdso_file * vdso_file)215 static const char *vdso__get_compat_file(struct vdso_file *vdso_file)
216 {
217 int err;
218
219 if (vdso_file->found)
220 return vdso_file->temp_file_name;
221
222 if (vdso_file->error)
223 return NULL;
224
225 err = vdso__create_compat_file(vdso_file->read_prog,
226 vdso_file->temp_file_name);
227 if (err) {
228 pr_err("%s failed, error %d\n", vdso_file->read_prog, err);
229 vdso_file->error = true;
230 return NULL;
231 }
232
233 vdso_file->found = true;
234
235 return vdso_file->temp_file_name;
236 }
237
__machine__findnew_compat(struct machine * machine,struct vdso_file * vdso_file)238 static struct dso *__machine__findnew_compat(struct machine *machine,
239 struct vdso_file *vdso_file)
240 {
241 const char *file_name;
242 struct dso *dso;
243
244 dso = __dsos__find(&machine->dsos, vdso_file->dso_name, true);
245 if (dso)
246 goto out;
247
248 file_name = vdso__get_compat_file(vdso_file);
249 if (!file_name)
250 goto out;
251
252 dso = __machine__addnew_vdso(machine, vdso_file->dso_name, file_name);
253 out:
254 return dso;
255 }
256
__machine__findnew_vdso_compat(struct machine * machine,struct thread * thread,struct vdso_info * vdso_info,struct dso ** dso)257 static int __machine__findnew_vdso_compat(struct machine *machine,
258 struct thread *thread,
259 struct vdso_info *vdso_info,
260 struct dso **dso)
261 {
262 enum dso_type dso_type;
263
264 dso_type = machine__thread_dso_type(machine, thread);
265
266 #ifndef HAVE_PERF_READ_VDSO32
267 if (dso_type == DSO__TYPE_32BIT)
268 return 0;
269 #endif
270 #ifndef HAVE_PERF_READ_VDSOX32
271 if (dso_type == DSO__TYPE_X32BIT)
272 return 0;
273 #endif
274
275 switch (dso_type) {
276 case DSO__TYPE_32BIT:
277 *dso = __machine__findnew_compat(machine, &vdso_info->vdso32);
278 return 1;
279 case DSO__TYPE_X32BIT:
280 *dso = __machine__findnew_compat(machine, &vdso_info->vdsox32);
281 return 1;
282 case DSO__TYPE_UNKNOWN:
283 case DSO__TYPE_64BIT:
284 default:
285 return 0;
286 }
287 }
288
289 #endif
290
machine__find_vdso(struct machine * machine,struct thread * thread)291 static struct dso *machine__find_vdso(struct machine *machine,
292 struct thread *thread)
293 {
294 struct dso *dso = NULL;
295 enum dso_type dso_type;
296
297 dso_type = machine__thread_dso_type(machine, thread);
298 switch (dso_type) {
299 case DSO__TYPE_32BIT:
300 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO32, true);
301 if (!dso) {
302 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO,
303 true);
304 if (dso && dso_type != dso__type(dso, machine))
305 dso = NULL;
306 }
307 break;
308 case DSO__TYPE_X32BIT:
309 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSOX32, true);
310 break;
311 case DSO__TYPE_64BIT:
312 case DSO__TYPE_UNKNOWN:
313 default:
314 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
315 break;
316 }
317
318 return dso;
319 }
320
machine__findnew_vdso(struct machine * machine,struct thread * thread)321 struct dso *machine__findnew_vdso(struct machine *machine,
322 struct thread *thread)
323 {
324 struct vdso_info *vdso_info;
325 struct dso *dso = NULL;
326
327 down_write(&machine->dsos.lock);
328 if (!machine->vdso_info)
329 machine->vdso_info = vdso_info__new();
330
331 vdso_info = machine->vdso_info;
332 if (!vdso_info)
333 goto out_unlock;
334
335 dso = machine__find_vdso(machine, thread);
336 if (dso)
337 goto out_unlock;
338
339 #if BITS_PER_LONG == 64
340 if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso))
341 goto out_unlock;
342 #endif
343
344 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
345 if (!dso) {
346 char *file;
347
348 file = get_file(&vdso_info->vdso);
349 if (file)
350 dso = __machine__addnew_vdso(machine, DSO__NAME_VDSO, file);
351 }
352
353 out_unlock:
354 dso__get(dso);
355 up_write(&machine->dsos.lock);
356 return dso;
357 }
358
dso__is_vdso(struct dso * dso)359 bool dso__is_vdso(struct dso *dso)
360 {
361 return !strcmp(dso->short_name, DSO__NAME_VDSO) ||
362 !strcmp(dso->short_name, DSO__NAME_VDSO32) ||
363 !strcmp(dso->short_name, DSO__NAME_VDSOX32);
364 }
365