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 "util.h" 14 #include "symbol.h" 15 #include "machine.h" 16 #include "thread.h" 17 #include "linux/string.h" 18 #include "debug.h" 19 20 /* 21 * Include definition of find_vdso_map() also used in perf-read-vdso.c for 22 * building perf-read-vdso32 and perf-read-vdsox32. 23 */ 24 #include "find-vdso-map.c" 25 26 #define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX" 27 28 struct vdso_file { 29 bool found; 30 bool error; 31 char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)]; 32 const char *dso_name; 33 const char *read_prog; 34 }; 35 36 struct vdso_info { 37 struct vdso_file vdso; 38 #if BITS_PER_LONG == 64 39 struct vdso_file vdso32; 40 struct vdso_file vdsox32; 41 #endif 42 }; 43 44 static struct vdso_info *vdso_info__new(void) 45 { 46 static const struct vdso_info vdso_info_init = { 47 .vdso = { 48 .temp_file_name = VDSO__TEMP_FILE_NAME, 49 .dso_name = DSO__NAME_VDSO, 50 }, 51 #if BITS_PER_LONG == 64 52 .vdso32 = { 53 .temp_file_name = VDSO__TEMP_FILE_NAME, 54 .dso_name = DSO__NAME_VDSO32, 55 .read_prog = "perf-read-vdso32", 56 }, 57 .vdsox32 = { 58 .temp_file_name = VDSO__TEMP_FILE_NAME, 59 .dso_name = DSO__NAME_VDSOX32, 60 .read_prog = "perf-read-vdsox32", 61 }, 62 #endif 63 }; 64 65 return memdup(&vdso_info_init, sizeof(vdso_info_init)); 66 } 67 68 static char *get_file(struct vdso_file *vdso_file) 69 { 70 char *vdso = NULL; 71 char *buf = NULL; 72 void *start, *end; 73 size_t size; 74 int fd; 75 76 if (vdso_file->found) 77 return vdso_file->temp_file_name; 78 79 if (vdso_file->error || find_vdso_map(&start, &end)) 80 return NULL; 81 82 size = end - start; 83 84 buf = memdup(start, size); 85 if (!buf) 86 return NULL; 87 88 fd = mkstemp(vdso_file->temp_file_name); 89 if (fd < 0) 90 goto out; 91 92 if (size == (size_t) write(fd, buf, size)) 93 vdso = vdso_file->temp_file_name; 94 95 close(fd); 96 97 out: 98 free(buf); 99 100 vdso_file->found = (vdso != NULL); 101 vdso_file->error = !vdso_file->found; 102 return vdso; 103 } 104 105 void machine__exit_vdso(struct machine *machine) 106 { 107 struct vdso_info *vdso_info = machine->vdso_info; 108 109 if (!vdso_info) 110 return; 111 112 if (vdso_info->vdso.found) 113 unlink(vdso_info->vdso.temp_file_name); 114 #if BITS_PER_LONG == 64 115 if (vdso_info->vdso32.found) 116 unlink(vdso_info->vdso32.temp_file_name); 117 if (vdso_info->vdsox32.found) 118 unlink(vdso_info->vdsox32.temp_file_name); 119 #endif 120 121 zfree(&machine->vdso_info); 122 } 123 124 static struct dso *__machine__addnew_vdso(struct machine *machine, const char *short_name, 125 const char *long_name) 126 { 127 struct dso *dso; 128 129 dso = dso__new(short_name); 130 if (dso != NULL) { 131 __dsos__add(&machine->dsos, dso); 132 dso__set_long_name(dso, long_name, false); 133 } 134 135 return dso; 136 } 137 138 static enum dso_type machine__thread_dso_type(struct machine *machine, 139 struct thread *thread) 140 { 141 enum dso_type dso_type = DSO__TYPE_UNKNOWN; 142 struct map *map; 143 struct dso *dso; 144 145 map = map_groups__first(thread->mg, MAP__FUNCTION); 146 for (; map ; map = map_groups__next(map)) { 147 dso = map->dso; 148 if (!dso || dso->long_name[0] != '/') 149 continue; 150 dso_type = dso__type(dso, machine); 151 if (dso_type != DSO__TYPE_UNKNOWN) 152 break; 153 } 154 155 return dso_type; 156 } 157 158 #if BITS_PER_LONG == 64 159 160 static int vdso__do_copy_compat(FILE *f, int fd) 161 { 162 char buf[4096]; 163 size_t count; 164 165 while (1) { 166 count = fread(buf, 1, sizeof(buf), f); 167 if (ferror(f)) 168 return -errno; 169 if (feof(f)) 170 break; 171 if (count && writen(fd, buf, count) != (ssize_t)count) 172 return -errno; 173 } 174 175 return 0; 176 } 177 178 static int vdso__copy_compat(const char *prog, int fd) 179 { 180 FILE *f; 181 int err; 182 183 f = popen(prog, "r"); 184 if (!f) 185 return -errno; 186 187 err = vdso__do_copy_compat(f, fd); 188 189 if (pclose(f) == -1) 190 return -errno; 191 192 return err; 193 } 194 195 static int vdso__create_compat_file(const char *prog, char *temp_name) 196 { 197 int fd, err; 198 199 fd = mkstemp(temp_name); 200 if (fd < 0) 201 return -errno; 202 203 err = vdso__copy_compat(prog, fd); 204 205 if (close(fd) == -1) 206 return -errno; 207 208 return err; 209 } 210 211 static const char *vdso__get_compat_file(struct vdso_file *vdso_file) 212 { 213 int err; 214 215 if (vdso_file->found) 216 return vdso_file->temp_file_name; 217 218 if (vdso_file->error) 219 return NULL; 220 221 err = vdso__create_compat_file(vdso_file->read_prog, 222 vdso_file->temp_file_name); 223 if (err) { 224 pr_err("%s failed, error %d\n", vdso_file->read_prog, err); 225 vdso_file->error = true; 226 return NULL; 227 } 228 229 vdso_file->found = true; 230 231 return vdso_file->temp_file_name; 232 } 233 234 static struct dso *__machine__findnew_compat(struct machine *machine, 235 struct vdso_file *vdso_file) 236 { 237 const char *file_name; 238 struct dso *dso; 239 240 dso = __dsos__find(&machine->dsos, vdso_file->dso_name, true); 241 if (dso) 242 goto out; 243 244 file_name = vdso__get_compat_file(vdso_file); 245 if (!file_name) 246 goto out; 247 248 dso = __machine__addnew_vdso(machine, vdso_file->dso_name, file_name); 249 out: 250 return dso; 251 } 252 253 static int __machine__findnew_vdso_compat(struct machine *machine, 254 struct thread *thread, 255 struct vdso_info *vdso_info, 256 struct dso **dso) 257 { 258 enum dso_type dso_type; 259 260 dso_type = machine__thread_dso_type(machine, thread); 261 262 #ifndef HAVE_PERF_READ_VDSO32 263 if (dso_type == DSO__TYPE_32BIT) 264 return 0; 265 #endif 266 #ifndef HAVE_PERF_READ_VDSOX32 267 if (dso_type == DSO__TYPE_X32BIT) 268 return 0; 269 #endif 270 271 switch (dso_type) { 272 case DSO__TYPE_32BIT: 273 *dso = __machine__findnew_compat(machine, &vdso_info->vdso32); 274 return 1; 275 case DSO__TYPE_X32BIT: 276 *dso = __machine__findnew_compat(machine, &vdso_info->vdsox32); 277 return 1; 278 case DSO__TYPE_UNKNOWN: 279 case DSO__TYPE_64BIT: 280 default: 281 return 0; 282 } 283 } 284 285 #endif 286 287 static struct dso *machine__find_vdso(struct machine *machine, 288 struct thread *thread) 289 { 290 struct dso *dso = NULL; 291 enum dso_type dso_type; 292 293 dso_type = machine__thread_dso_type(machine, thread); 294 switch (dso_type) { 295 case DSO__TYPE_32BIT: 296 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO32, true); 297 if (!dso) { 298 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, 299 true); 300 if (dso && dso_type != dso__type(dso, machine)) 301 dso = NULL; 302 } 303 break; 304 case DSO__TYPE_X32BIT: 305 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSOX32, true); 306 break; 307 case DSO__TYPE_64BIT: 308 case DSO__TYPE_UNKNOWN: 309 default: 310 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true); 311 break; 312 } 313 314 return dso; 315 } 316 317 struct dso *machine__findnew_vdso(struct machine *machine, 318 struct thread *thread) 319 { 320 struct vdso_info *vdso_info; 321 struct dso *dso = NULL; 322 323 down_write(&machine->dsos.lock); 324 if (!machine->vdso_info) 325 machine->vdso_info = vdso_info__new(); 326 327 vdso_info = machine->vdso_info; 328 if (!vdso_info) 329 goto out_unlock; 330 331 dso = machine__find_vdso(machine, thread); 332 if (dso) 333 goto out_unlock; 334 335 #if BITS_PER_LONG == 64 336 if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso)) 337 goto out_unlock; 338 #endif 339 340 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true); 341 if (!dso) { 342 char *file; 343 344 file = get_file(&vdso_info->vdso); 345 if (file) 346 dso = __machine__addnew_vdso(machine, DSO__NAME_VDSO, file); 347 } 348 349 out_unlock: 350 dso__get(dso); 351 up_write(&machine->dsos.lock); 352 return dso; 353 } 354 355 bool dso__is_vdso(struct dso *dso) 356 { 357 return !strcmp(dso->short_name, DSO__NAME_VDSO) || 358 !strcmp(dso->short_name, DSO__NAME_VDSO32) || 359 !strcmp(dso->short_name, DSO__NAME_VDSOX32); 360 } 361