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