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
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
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
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
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
141 struct machine__thread_dso_type_maps_cb_args {
142 struct machine *machine;
143 enum dso_type dso_type;
144 };
145
146 static int machine__thread_dso_type_maps_cb(struct map *map, void *data)
147 {
148 struct machine__thread_dso_type_maps_cb_args *args = data;
149 struct dso *dso = map__dso(map);
150
151 if (!dso || dso__long_name(dso)[0] != '/')
152 return 0;
153
154 args->dso_type = dso__type(dso, args->machine);
155 return (args->dso_type != DSO__TYPE_UNKNOWN) ? 1 : 0;
156 }
157
158 static enum dso_type machine__thread_dso_type(struct machine *machine,
159 struct thread *thread)
160 {
161 struct machine__thread_dso_type_maps_cb_args args = {
162 .machine = machine,
163 .dso_type = DSO__TYPE_UNKNOWN,
164 };
165
166 maps__for_each_map(thread__maps(thread), machine__thread_dso_type_maps_cb, &args);
167
168 return args.dso_type;
169 }
170
171 #if BITS_PER_LONG == 64
172
173 static int vdso__do_copy_compat(FILE *f, int fd)
174 {
175 char buf[4096];
176 size_t count;
177
178 while (1) {
179 count = fread(buf, 1, sizeof(buf), f);
180 if (ferror(f))
181 return -errno;
182 if (feof(f))
183 break;
184 if (count && writen(fd, buf, count) != (ssize_t)count)
185 return -errno;
186 }
187
188 return 0;
189 }
190
191 static int vdso__copy_compat(const char *prog, int fd)
192 {
193 FILE *f;
194 int err;
195
196 f = popen(prog, "r");
197 if (!f)
198 return -errno;
199
200 err = vdso__do_copy_compat(f, fd);
201
202 if (pclose(f) == -1)
203 return -errno;
204
205 return err;
206 }
207
208 static int vdso__create_compat_file(const char *prog, char *temp_name)
209 {
210 int fd, err;
211
212 fd = mkstemp(temp_name);
213 if (fd < 0)
214 return -errno;
215
216 err = vdso__copy_compat(prog, fd);
217
218 if (close(fd) == -1)
219 return -errno;
220
221 return err;
222 }
223
224 static const char *vdso__get_compat_file(struct vdso_file *vdso_file)
225 {
226 int err;
227
228 if (vdso_file->found)
229 return vdso_file->temp_file_name;
230
231 if (vdso_file->error)
232 return NULL;
233
234 err = vdso__create_compat_file(vdso_file->read_prog,
235 vdso_file->temp_file_name);
236 if (err) {
237 pr_err("%s failed, error %d\n", vdso_file->read_prog, err);
238 vdso_file->error = true;
239 return NULL;
240 }
241
242 vdso_file->found = true;
243
244 return vdso_file->temp_file_name;
245 }
246
247 static struct dso *__machine__findnew_compat(struct machine *machine,
248 struct vdso_file *vdso_file)
249 {
250 const char *file_name;
251 struct dso *dso;
252
253 dso = dsos__find(&machine->dsos, vdso_file->dso_name, true);
254 if (dso)
255 return dso;
256
257 file_name = vdso__get_compat_file(vdso_file);
258 if (!file_name)
259 return NULL;
260
261 return __machine__addnew_vdso(machine, vdso_file->dso_name, file_name);
262 }
263
264 static int __machine__findnew_vdso_compat(struct machine *machine,
265 struct thread *thread,
266 struct vdso_info *vdso_info,
267 struct dso **dso)
268 {
269 enum dso_type dso_type;
270
271 dso_type = machine__thread_dso_type(machine, thread);
272
273 #ifndef HAVE_PERF_READ_VDSO32
274 if (dso_type == DSO__TYPE_32BIT)
275 return 0;
276 #endif
277 #ifndef HAVE_PERF_READ_VDSOX32
278 if (dso_type == DSO__TYPE_X32BIT)
279 return 0;
280 #endif
281
282 switch (dso_type) {
283 case DSO__TYPE_32BIT:
284 *dso = __machine__findnew_compat(machine, &vdso_info->vdso32);
285 return 1;
286 case DSO__TYPE_X32BIT:
287 *dso = __machine__findnew_compat(machine, &vdso_info->vdsox32);
288 return 1;
289 case DSO__TYPE_UNKNOWN:
290 case DSO__TYPE_64BIT:
291 default:
292 return 0;
293 }
294 }
295
296 #endif
297
298 static struct dso *machine__find_vdso(struct machine *machine,
299 struct thread *thread)
300 {
301 struct dso *dso = NULL;
302 enum dso_type dso_type;
303
304 dso_type = machine__thread_dso_type(machine, thread);
305 switch (dso_type) {
306 case DSO__TYPE_32BIT:
307 dso = dsos__find(&machine->dsos, DSO__NAME_VDSO32, true);
308 if (!dso) {
309 dso = dsos__find(&machine->dsos, DSO__NAME_VDSO,
310 true);
311 if (dso && dso_type != dso__type(dso, machine))
312 dso = NULL;
313 }
314 break;
315 case DSO__TYPE_X32BIT:
316 dso = dsos__find(&machine->dsos, DSO__NAME_VDSOX32, true);
317 break;
318 case DSO__TYPE_64BIT:
319 case DSO__TYPE_UNKNOWN:
320 default:
321 dso = dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
322 break;
323 }
324
325 return dso;
326 }
327
328 struct dso *machine__findnew_vdso(struct machine *machine,
329 struct thread *thread)
330 {
331 struct vdso_info *vdso_info;
332 struct dso *dso = NULL;
333 char *file;
334
335 if (!machine->vdso_info)
336 machine->vdso_info = vdso_info__new();
337
338 vdso_info = machine->vdso_info;
339 if (!vdso_info)
340 return NULL;
341
342 dso = machine__find_vdso(machine, thread);
343 if (dso)
344 return dso;
345
346 #if BITS_PER_LONG == 64
347 if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso))
348 return dso;
349 #endif
350
351 dso = dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
352 if (dso)
353 return dso;
354
355 file = get_file(&vdso_info->vdso);
356 if (!file)
357 return NULL;
358
359 return __machine__addnew_vdso(machine, DSO__NAME_VDSO, file);
360 }
361
362 bool dso__is_vdso(struct dso *dso)
363 {
364 return !strcmp(dso__short_name(dso), DSO__NAME_VDSO) ||
365 !strcmp(dso__short_name(dso), DSO__NAME_VDSO32) ||
366 !strcmp(dso__short_name(dso), DSO__NAME_VDSOX32);
367 }
368
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.