1 #include <errno.h> 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 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 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 } 103 104 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 } 122 123 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 } 136 137 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 == 64 158 159 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 } 176 177 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 } 193 194 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 } 209 210 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 } 232 233 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 } 251 252 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 285 286 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 } 315 316 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 } 353 354 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