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 /* Put dso here because __dsos_add already got it */ 137 dso__put(dso); 138 } 139 140 return dso; 141 } 142 143 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 *map; 148 149 maps__for_each_entry(thread->maps, map) { 150 struct dso *dso = map->dso; 151 if (!dso || dso->long_name[0] != '/') 152 continue; 153 dso_type = dso__type(dso, machine); 154 if (dso_type != DSO__TYPE_UNKNOWN) 155 break; 156 } 157 158 return dso_type; 159 } 160 161 #if BITS_PER_LONG == 64 162 163 static int vdso__do_copy_compat(FILE *f, int fd) 164 { 165 char buf[4096]; 166 size_t count; 167 168 while (1) { 169 count = fread(buf, 1, sizeof(buf), f); 170 if (ferror(f)) 171 return -errno; 172 if (feof(f)) 173 break; 174 if (count && writen(fd, buf, count) != (ssize_t)count) 175 return -errno; 176 } 177 178 return 0; 179 } 180 181 static int vdso__copy_compat(const char *prog, int fd) 182 { 183 FILE *f; 184 int err; 185 186 f = popen(prog, "r"); 187 if (!f) 188 return -errno; 189 190 err = vdso__do_copy_compat(f, fd); 191 192 if (pclose(f) == -1) 193 return -errno; 194 195 return err; 196 } 197 198 static int vdso__create_compat_file(const char *prog, char *temp_name) 199 { 200 int fd, err; 201 202 fd = mkstemp(temp_name); 203 if (fd < 0) 204 return -errno; 205 206 err = vdso__copy_compat(prog, fd); 207 208 if (close(fd) == -1) 209 return -errno; 210 211 return err; 212 } 213 214 static const char *vdso__get_compat_file(struct vdso_file *vdso_file) 215 { 216 int err; 217 218 if (vdso_file->found) 219 return vdso_file->temp_file_name; 220 221 if (vdso_file->error) 222 return NULL; 223 224 err = vdso__create_compat_file(vdso_file->read_prog, 225 vdso_file->temp_file_name); 226 if (err) { 227 pr_err("%s failed, error %d\n", vdso_file->read_prog, err); 228 vdso_file->error = true; 229 return NULL; 230 } 231 232 vdso_file->found = true; 233 234 return vdso_file->temp_file_name; 235 } 236 237 static struct dso *__machine__findnew_compat(struct machine *machine, 238 struct vdso_file *vdso_file) 239 { 240 const char *file_name; 241 struct dso *dso; 242 243 dso = __dsos__find(&machine->dsos, vdso_file->dso_name, true); 244 if (dso) 245 goto out; 246 247 file_name = vdso__get_compat_file(vdso_file); 248 if (!file_name) 249 goto out; 250 251 dso = __machine__addnew_vdso(machine, vdso_file->dso_name, file_name); 252 out: 253 return dso; 254 } 255 256 static int __machine__findnew_vdso_compat(struct machine *machine, 257 struct thread *thread, 258 struct vdso_info *vdso_info, 259 struct dso **dso) 260 { 261 enum dso_type dso_type; 262 263 dso_type = machine__thread_dso_type(machine, thread); 264 265 #ifndef HAVE_PERF_READ_VDSO32 266 if (dso_type == DSO__TYPE_32BIT) 267 return 0; 268 #endif 269 #ifndef HAVE_PERF_READ_VDSOX32 270 if (dso_type == DSO__TYPE_X32BIT) 271 return 0; 272 #endif 273 274 switch (dso_type) { 275 case DSO__TYPE_32BIT: 276 *dso = __machine__findnew_compat(machine, &vdso_info->vdso32); 277 return 1; 278 case DSO__TYPE_X32BIT: 279 *dso = __machine__findnew_compat(machine, &vdso_info->vdsox32); 280 return 1; 281 case DSO__TYPE_UNKNOWN: 282 case DSO__TYPE_64BIT: 283 default: 284 return 0; 285 } 286 } 287 288 #endif 289 290 static struct dso *machine__find_vdso(struct machine *machine, 291 struct thread *thread) 292 { 293 struct dso *dso = NULL; 294 enum dso_type dso_type; 295 296 dso_type = machine__thread_dso_type(machine, thread); 297 switch (dso_type) { 298 case DSO__TYPE_32BIT: 299 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO32, true); 300 if (!dso) { 301 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, 302 true); 303 if (dso && dso_type != dso__type(dso, machine)) 304 dso = NULL; 305 } 306 break; 307 case DSO__TYPE_X32BIT: 308 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSOX32, true); 309 break; 310 case DSO__TYPE_64BIT: 311 case DSO__TYPE_UNKNOWN: 312 default: 313 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true); 314 break; 315 } 316 317 return dso; 318 } 319 320 struct dso *machine__findnew_vdso(struct machine *machine, 321 struct thread *thread) 322 { 323 struct vdso_info *vdso_info; 324 struct dso *dso = NULL; 325 326 down_write(&machine->dsos.lock); 327 if (!machine->vdso_info) 328 machine->vdso_info = vdso_info__new(); 329 330 vdso_info = machine->vdso_info; 331 if (!vdso_info) 332 goto out_unlock; 333 334 dso = machine__find_vdso(machine, thread); 335 if (dso) 336 goto out_unlock; 337 338 #if BITS_PER_LONG == 64 339 if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso)) 340 goto out_unlock; 341 #endif 342 343 dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true); 344 if (!dso) { 345 char *file; 346 347 file = get_file(&vdso_info->vdso); 348 if (file) 349 dso = __machine__addnew_vdso(machine, DSO__NAME_VDSO, file); 350 } 351 352 out_unlock: 353 dso__get(dso); 354 up_write(&machine->dsos.lock); 355 return dso; 356 } 357 358 bool dso__is_vdso(struct dso *dso) 359 { 360 return !strcmp(dso->short_name, DSO__NAME_VDSO) || 361 !strcmp(dso->short_name, DSO__NAME_VDSO32) || 362 !strcmp(dso->short_name, DSO__NAME_VDSOX32); 363 } 364