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 "map.h" 15 #include "symbol.h" 16 #include "machine.h" 17 #include "thread.h" 18 #include "linux/string.h" 19 #include "debug.h" 20 21 /* 22 * Include definition of find_map() also used in perf-read-vdso.c for 23 * building perf-read-vdso32 and perf-read-vdsox32. 24 */ 25 #include "find-map.c" 26 27 #define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX" 28 29 struct vdso_file { 30 bool found; 31 bool error; 32 char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)]; 33 const char *dso_name; 34 const char *read_prog; 35 }; 36 37 struct vdso_info { 38 struct vdso_file vdso; 39 #if BITS_PER_LONG == 64 40 struct vdso_file vdso32; 41 struct vdso_file vdsox32; 42 #endif 43 }; 44 45 static struct vdso_info *vdso_info__new(void) 46 { 47 static const struct vdso_info vdso_info_init = { 48 .vdso = { 49 .temp_file_name = VDSO__TEMP_FILE_NAME, 50 .dso_name = DSO__NAME_VDSO, 51 }, 52 #if BITS_PER_LONG == 64 53 .vdso32 = { 54 .temp_file_name = VDSO__TEMP_FILE_NAME, 55 .dso_name = DSO__NAME_VDSO32, 56 .read_prog = "perf-read-vdso32", 57 }, 58 .vdsox32 = { 59 .temp_file_name = VDSO__TEMP_FILE_NAME, 60 .dso_name = DSO__NAME_VDSOX32, 61 .read_prog = "perf-read-vdsox32", 62 }, 63 #endif 64 }; 65 66 return memdup(&vdso_info_init, sizeof(vdso_info_init)); 67 } 68 69 static char *get_file(struct vdso_file *vdso_file) 70 { 71 char *vdso = NULL; 72 char *buf = NULL; 73 void *start, *end; 74 size_t size; 75 int fd; 76 77 if (vdso_file->found) 78 return vdso_file->temp_file_name; 79 80 if (vdso_file->error || find_map(&start, &end, VDSO__MAP_NAME)) 81 return NULL; 82 83 size = end - start; 84 85 buf = memdup(start, size); 86 if (!buf) 87 return NULL; 88 89 fd = mkstemp(vdso_file->temp_file_name); 90 if (fd < 0) 91 goto out; 92 93 if (size == (size_t) write(fd, buf, size)) 94 vdso = vdso_file->temp_file_name; 95 96 close(fd); 97 98 out: 99 free(buf); 100 101 vdso_file->found = (vdso != NULL); 102 vdso_file->error = !vdso_file->found; 103 return vdso; 104 } 105 106 void machine__exit_vdso(struct machine *machine) 107 { 108 struct vdso_info *vdso_info = machine->vdso_info; 109 110 if (!vdso_info) 111 return; 112 113 if (vdso_info->vdso.found) 114 unlink(vdso_info->vdso.temp_file_name); 115 #if BITS_PER_LONG == 64 116 if (vdso_info->vdso32.found) 117 unlink(vdso_info->vdso32.temp_file_name); 118 if (vdso_info->vdsox32.found) 119 unlink(vdso_info->vdsox32.temp_file_name); 120 #endif 121 122 zfree(&machine->vdso_info); 123 } 124 125 static struct dso *__machine__addnew_vdso(struct machine *machine, const char *short_name, 126 const char *long_name) 127 { 128 struct dso *dso; 129 130 dso = dso__new(short_name); 131 if (dso != NULL) { 132 __dsos__add(&machine->dsos, dso); 133 dso__set_long_name(dso, long_name, false); 134 } 135 136 return dso; 137 } 138 139 static enum dso_type machine__thread_dso_type(struct machine *machine, 140 struct thread *thread) 141 { 142 enum dso_type dso_type = DSO__TYPE_UNKNOWN; 143 struct map *map = map_groups__first(thread->mg); 144 145 for (; map ; map = map_groups__next(map)) { 146 struct dso *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 down_write(&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 up_write(&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