lib/libproc/proc_sym.c

   1 /*-
   2  * Copyright (c) 2010 The FreeBSD Foundation
   3  * Copyright (c) 2008 John Birrell (jb@freebsd.org)
   4  * All rights reserved.
   5  *
   6  * Portions of this software were developed by Rui Paulo under sponsorship
   7  * from the FreeBSD Foundation.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  *
  30  * $FreeBSD$
  31  */
  32
  33 #include <sys/types.h>
  34 #include <sys/user.h>
  35
  36 #include <assert.h>
  37 #include <err.h>
  38 #include <stdio.h>
  39 #include <libgen.h>
  40 #include <string.h>
  41 #include <stdlib.h>
  42 #include <fcntl.h>
  43 #include <string.h>
  44 #include <unistd.h>
  45 #include <libutil.h>
  46
  47 #include "_libproc.h"
  48
  49 #ifndef NO_CXA_DEMANGLE
  50 extern char *__cxa_demangle(const char *, char *, size_t *, int *);
  51 #endif /* NO_CXA_DEMANGLE */
  52
  53 static void     proc_rdl2prmap(rd_loadobj_t *, prmap_t *);
  54
  55 static void
  56 demangle(const char *symbol, char *buf, size_t len)
  57 {
  58 #ifndef NO_CXA_DEMANGLE
  59         char *dembuf;
  60
  61         if (symbol[0] == '_' && symbol[1] == 'Z' && symbol[2]) {
  62                 dembuf = __cxa_demangle(symbol, NULL, NULL, NULL);
  63                 if (!dembuf)
  64                         goto fail;
  65                 strlcpy(buf, dembuf, len);
  66                 free(dembuf);
  67                 return;
  68         }
  69 fail:
  70 #endif /* NO_CXA_DEMANGLE */
  71         strlcpy(buf, symbol, len);
  72 }
  73
  74 static void
  75 proc_rdl2prmap(rd_loadobj_t *rdl, prmap_t *map)
  76 {
  77         map->pr_vaddr = rdl->rdl_saddr;
  78         map->pr_size = rdl->rdl_eaddr - rdl->rdl_saddr;
  79         map->pr_offset = rdl->rdl_offset;
  80         map->pr_mflags = 0;
  81         if (rdl->rdl_prot & RD_RDL_R)
  82                 map->pr_mflags |= MA_READ;
  83         if (rdl->rdl_prot & RD_RDL_W)
  84                 map->pr_mflags |= MA_WRITE;
  85         if (rdl->rdl_prot & RD_RDL_X)
  86                 map->pr_mflags |= MA_EXEC;
  87         strlcpy(map->pr_mapname, rdl->rdl_path,
  88             sizeof(map->pr_mapname));
  89 }
  90
  91 char *
  92 proc_objname(struct proc_handle *p, uintptr_t addr, char *objname,
  93     size_t objnamesz)
  94 {
  95         size_t i;
  96         rd_loadobj_t *rdl;
  97
  98         for (i = 0; i < p->nobjs; i++) {
  99                 rdl = &p->rdobjs[i];
 100                 if (addr >= rdl->rdl_saddr && addr < rdl->rdl_eaddr) {
 101                         strlcpy(objname, rdl->rdl_path, objnamesz);
 102                         return (objname);
 103                 }
 104         }
 105         return (NULL);
 106 }
 107
 108 prmap_t *
 109 proc_obj2map(struct proc_handle *p, const char *objname)
 110 {
 111         size_t i;
 112         prmap_t *map;
 113         rd_loadobj_t *rdl;
 114         char path[MAXPATHLEN];
 115
 116         rdl = NULL;
 117         for (i = 0; i < p->nobjs; i++) {
 118                 basename_r(p->rdobjs[i].rdl_path, path);
 119                 if (strcmp(path, objname) == 0) {
 120                         rdl = &p->rdobjs[i];
 121                         break;
 122                 }
 123         }
 124         if (rdl == NULL && strcmp(objname, "a.out") == 0 && p->rdexec != NULL)
 125                 rdl = p->rdexec;
 126         else
 127                 return (NULL);
 128
 129         if ((map = malloc(sizeof(*map))) == NULL)
 130                 return (NULL);
 131         proc_rdl2prmap(rdl, map);
 132         return (map);
 133 }
 134
 135 int
 136 proc_iter_objs(struct proc_handle *p, proc_map_f *func, void *cd)
 137 {
 138         size_t i;
 139         rd_loadobj_t *rdl;
 140         prmap_t map;
 141         char path[MAXPATHLEN];
 142         char last[MAXPATHLEN];
 143
 144         if (p->nobjs == 0)
 145                 return (-1);
 146         memset(last, 0, sizeof(last));
 147         for (i = 0; i < p->nobjs; i++) {
 148                 rdl = &p->rdobjs[i];
 149                 proc_rdl2prmap(rdl, &map);
 150                 basename_r(rdl->rdl_path, path);
 151                 /*
 152                  * We shouldn't call the callback twice with the same object.
 153                  * To do that we are assuming the fact that if there are
 154                  * repeated object names (i.e. different mappings for the
 155                  * same object) they occur next to each other.
 156                  */
 157                 if (strcmp(path, last) == 0)
 158                         continue;
 159                 (*func)(cd, &map, path);
 160                 strlcpy(last, path, sizeof(last));
 161         }
 162
 163         return (0);
 164 }
 165
 166 prmap_t *
 167 proc_addr2map(struct proc_handle *p, uintptr_t addr)
 168 {
 169         size_t i;
 170         int cnt, lastvn = 0;
 171         prmap_t *map;
 172         rd_loadobj_t *rdl;
 173         struct kinfo_vmentry *kves, *kve;
 174
 175         /*
 176          * If we don't have a cache of listed objects, we need to query
 177          * it ourselves.
 178          */
 179         if (p->nobjs == 0) {
 180                 if ((kves = kinfo_getvmmap(p->pid, &cnt)) == NULL)
 181                         return (NULL);
 182                 for (i = 0; i < (size_t)cnt; i++) {
 183                         kve = kves + i;
 184                         if (kve->kve_type == KVME_TYPE_VNODE)
 185                                 lastvn = i;
 186                         if (addr >= kve->kve_start && addr < kve->kve_end) {
 187                                 if ((map = malloc(sizeof(*map))) == NULL) {
 188                                         free(kves);
 189                                         return (NULL);
 190                                 }
 191                                 map->pr_vaddr = kve->kve_start;
 192                                 map->pr_size = kve->kve_end - kve->kve_start;
 193                                 map->pr_offset = kve->kve_offset;
 194                                 map->pr_mflags = 0;
 195                                 if (kve->kve_protection & KVME_PROT_READ)
 196                                         map->pr_mflags |= MA_READ;
 197                                 if (kve->kve_protection & KVME_PROT_WRITE)
 198                                         map->pr_mflags |= MA_WRITE;
 199                                 if (kve->kve_protection & KVME_PROT_EXEC)
 200                                         map->pr_mflags |= MA_EXEC;
 201                                 if (kve->kve_flags & KVME_FLAG_COW)
 202                                         map->pr_mflags |= MA_COW;
 203                                 if (kve->kve_flags & KVME_FLAG_NEEDS_COPY)
 204                                         map->pr_mflags |= MA_NEEDS_COPY;
 205                                 if (kve->kve_flags & KVME_FLAG_NOCOREDUMP)
 206                                         map->pr_mflags |= MA_NOCOREDUMP;
 207                                 strlcpy(map->pr_mapname, kves[lastvn].kve_path,
 208                                     sizeof(map->pr_mapname));
 209                                 free(kves);
 210                                 return (map);
 211                         }
 212                 }
 213                 free(kves);
 214                 return (NULL);
 215         }
 216
 217         for (i = 0; i < p->nobjs; i++) {
 218                 rdl = &p->rdobjs[i];
 219                 if (addr >= rdl->rdl_saddr && addr < rdl->rdl_eaddr) {
 220                         if ((map = malloc(sizeof(*map))) == NULL)
 221                                 return (NULL);
 222                         proc_rdl2prmap(rdl, map);
 223                         return (map);
 224                 }
 225         }
 226         return (NULL);
 227 }
 228
 229 int
 230 proc_addr2sym(struct proc_handle *p, uintptr_t addr, char *name,
 231     size_t namesz, GElf_Sym *symcopy)
 232 {
 233         Elf *e;
 234         Elf_Scn *scn, *dynsymscn = NULL, *symtabscn = NULL;
 235         Elf_Data *data;
 236         GElf_Shdr shdr;
 237         GElf_Sym sym;
 238         GElf_Ehdr ehdr;
 239         int fd, error = -1;
 240         size_t i;
 241         uint64_t rsym;
 242         prmap_t *map;
 243         char *s;
 244         unsigned long symtabstridx = 0, dynsymstridx = 0;
 245
 246         if ((map = proc_addr2map(p, addr)) == NULL)
 247                 return (-1);
 248         if ((fd = open(map->pr_mapname, O_RDONLY, 0)) < 0) {
 249                 DPRINTF("ERROR: open %s failed", map->pr_mapname);
 250                 goto err0;
 251         }
 252         if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
 253                 DPRINTFX("ERROR: elf_begin() failed: %s", elf_errmsg(-1));
 254                 goto err1;
 255         }
 256         if (gelf_getehdr(e, &ehdr) == NULL) {
 257                 DPRINTFX("ERROR: gelf_getehdr() failed: %s", elf_errmsg(-1));
 258                 goto err2;
 259         }
 260         /*
 261          * Find the index of the STRTAB and SYMTAB sections to locate
 262          * symbol names.
 263          */
 264         scn = NULL;
 265         while ((scn = elf_nextscn(e, scn)) != NULL) {
 266                 gelf_getshdr(scn, &shdr);
 267                 switch (shdr.sh_type) {
 268                 case SHT_SYMTAB:
 269                         symtabscn = scn;
 270                         symtabstridx = shdr.sh_link;
 271                         break;
 272                 case SHT_DYNSYM:
 273                         dynsymscn = scn;
 274                         dynsymstridx = shdr.sh_link;
 275                         break;
 276                 default:
 277                         break;
 278                 }
 279         }
 280         /*
 281          * Iterate over the Dynamic Symbols table to find the symbol.
 282          * Then look up the string name in STRTAB (.dynstr)
 283          */
 284         if ((data = elf_getdata(dynsymscn, NULL)) == NULL) {
 285                 DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1));
 286                 goto symtab;
 287         }
 288         i = 0;
 289         while (gelf_getsym(data, i++, &sym) != NULL) {
 290                 /*
 291                  * Calculate the address mapped to the virtual memory
 292                  * by rtld.
 293                  */
 294                 if (ehdr.e_type != ET_EXEC)
 295                         rsym = map->pr_vaddr + sym.st_value;
 296                 else
 297                         rsym = sym.st_value;
 298                 if (addr >= rsym && addr < rsym + sym.st_size) {
 299                         s = elf_strptr(e, dynsymstridx, sym.st_name);
 300                         if (s) {
 301                                 demangle(s, name, namesz);
 302                                 memcpy(symcopy, &sym, sizeof(sym));
 303                                 /*
 304                                  * DTrace expects the st_value to contain
 305                                  * only the address relative to the start of
 306                                  * the function.
 307                                  */
 308                                 symcopy->st_value = rsym;
 309                                 error = 0;
 310                                 goto out;
 311                         }
 312                 }
 313         }
 314 symtab:
 315         /*
 316          * Iterate over the Symbols Table to find the symbol.
 317          * Then look up the string name in STRTAB (.dynstr)
 318          */
 319         if ((data = elf_getdata(symtabscn, NULL)) == NULL) {
 320                 DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1));
 321                 goto err2;
 322         }
 323         i = 0;
 324         while (gelf_getsym(data, i++, &sym) != NULL) {
 325                 /*
 326                  * Calculate the address mapped to the virtual memory
 327                  * by rtld.
 328                  */
 329                 if (ehdr.e_type != ET_EXEC)
 330                         rsym = map->pr_vaddr + sym.st_value;
 331                 else
 332                         rsym = sym.st_value;
 333                 if (addr >= rsym && addr < rsym + sym.st_size) {
 334                         s = elf_strptr(e, symtabstridx, sym.st_name);
 335                         if (s) {
 336                                 demangle(s, name, namesz);
 337                                 memcpy(symcopy, &sym, sizeof(sym));
 338                                 /*
 339                                  * DTrace expects the st_value to contain
 340                                  * only the address relative to the start of
 341                                  * the function.
 342                                  */
 343                                 symcopy->st_value = rsym;
 344                                 error = 0;
 345                                 goto out;
 346                         }
 347                 }
 348         }
 349 out:
 350 err2:
 351         elf_end(e);
 352 err1:
 353         close(fd);
 354 err0:
 355         free(map);
 356         return (error);
 357 }
 358
 359 prmap_t *
 360 proc_name2map(struct proc_handle *p, const char *name)
 361 {
 362         size_t i;
 363         int cnt;
 364         prmap_t *map;
 365         char tmppath[MAXPATHLEN];
 366         struct kinfo_vmentry *kves, *kve;
 367         rd_loadobj_t *rdl;
 368
 369         /*
 370          * If we haven't iterated over the list of loaded objects,
 371          * librtld_db isn't yet initialized and it's very likely
 372          * that librtld_db called us. We need to do the heavy
 373          * lifting here to find the symbol librtld_db is looking for.
 374          */
 375         if (p->nobjs == 0) {
 376                 if ((kves = kinfo_getvmmap(proc_getpid(p), &cnt)) == NULL)
 377                         return (NULL);
 378                 for (i = 0; i < (size_t)cnt; i++) {
 379                         kve = kves + i;
 380                         basename_r(kve->kve_path, tmppath);
 381                         if (strcmp(tmppath, name) == 0) {
 382                                 map = proc_addr2map(p, kve->kve_start);
 383                                 free(kves);
 384                                 return (map);
 385                         }
 386                 }
 387                 free(kves);
 388                 return (NULL);
 389         }
 390         if ((name == NULL || strcmp(name, "a.out") == 0) &&
 391             p->rdexec != NULL) {
 392                 map = proc_addr2map(p, p->rdexec->rdl_saddr);
 393                 return (map);
 394         }
 395         for (i = 0; i < p->nobjs; i++) {
 396                 rdl = &p->rdobjs[i];
 397                 basename_r(rdl->rdl_path, tmppath);
 398                 if (strcmp(tmppath, name) == 0) {
 399                         if ((map = malloc(sizeof(*map))) == NULL)
 400                                 return (NULL);
 401                         proc_rdl2prmap(rdl, map);
 402                         return (map);
 403                 }
 404         }
 405
 406         return (NULL);
 407 }
 408
 409 int
 410 proc_name2sym(struct proc_handle *p, const char *object, const char *symbol,
 411     GElf_Sym *symcopy)
 412 {
 413         Elf *e;
 414         Elf_Scn *scn, *dynsymscn = NULL, *symtabscn = NULL;
 415         Elf_Data *data;
 416         GElf_Shdr shdr;
 417         GElf_Sym sym;
 418         GElf_Ehdr ehdr;
 419         int fd, error = -1;
 420         size_t i;
 421         prmap_t *map;
 422         char *s;
 423         unsigned long symtabstridx = 0, dynsymstridx = 0;
 424
 425         if ((map = proc_name2map(p, object)) == NULL) {
 426                 DPRINTFX("ERROR: couldn't find object %s", object);
 427                 goto err0;
 428         }
 429         if ((fd = open(map->pr_mapname, O_RDONLY, 0)) < 0) {
 430                 DPRINTF("ERROR: open %s failed", map->pr_mapname);
 431                 goto err0;
 432         }
 433         if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
 434                 DPRINTFX("ERROR: elf_begin() failed: %s", elf_errmsg(-1));
 435                 goto err1;
 436         }
 437         if (gelf_getehdr(e, &ehdr) == NULL) {
 438                 DPRINTFX("ERROR: gelf_getehdr() failed: %s", elf_errmsg(-1));
 439                 goto err2;
 440         }
 441         /*
 442          * Find the index of the STRTAB and SYMTAB sections to locate
 443          * symbol names.
 444          */
 445         scn = NULL;
 446         while ((scn = elf_nextscn(e, scn)) != NULL) {
 447                 gelf_getshdr(scn, &shdr);
 448                 switch (shdr.sh_type) {
 449                 case SHT_SYMTAB:
 450                         symtabscn = scn;
 451                         symtabstridx = shdr.sh_link;
 452                         break;
 453                 case SHT_DYNSYM:
 454                         dynsymscn = scn;
 455                         dynsymstridx = shdr.sh_link;
 456                         break;
 457                 default:
 458                         break;
 459                 }
 460         }
 461         /*
 462          * Iterate over the Dynamic Symbols table to find the symbol.
 463          * Then look up the string name in STRTAB (.dynstr)
 464          */
 465         if ((data = elf_getdata(dynsymscn, NULL))) {
 466                 i = 0;
 467                 while (gelf_getsym(data, i++, &sym) != NULL) {
 468                         s = elf_strptr(e, dynsymstridx, sym.st_name);
 469                         if (s && strcmp(s, symbol) == 0) {
 470                                 memcpy(symcopy, &sym, sizeof(sym));
 471                                 if (ehdr.e_type != ET_EXEC)
 472                                         symcopy->st_value += map->pr_vaddr;
 473                                 error = 0;
 474                                 goto out;
 475                         }
 476                 }
 477         }
 478         /*
 479          * Iterate over the Symbols Table to find the symbol.
 480          * Then look up the string name in STRTAB (.dynstr)
 481          */
 482         if ((data = elf_getdata(symtabscn, NULL))) {
 483                 i = 0;
 484                 while (gelf_getsym(data, i++, &sym) != NULL) {
 485                         s = elf_strptr(e, symtabstridx, sym.st_name);
 486                         if (s && strcmp(s, symbol) == 0) {
 487                                 memcpy(symcopy, &sym, sizeof(sym));
 488                                 if (ehdr.e_type != ET_EXEC)
 489                                         symcopy->st_value += map->pr_vaddr;
 490                                 error = 0;
 491                                 goto out;
 492                         }
 493                 }
 494         }
 495 out:
 496         DPRINTFX("found addr 0x%lx for %s", symcopy->st_value, symbol);
 497 err2:
 498         elf_end(e);
 499 err1:
 500         close(fd);
 501 err0:
 502         free(map);
 503
 504         return (error);
 505 }
 506
 507
 508 int
 509 proc_iter_symbyaddr(struct proc_handle *p, const char *object, int which,
 510     int mask, proc_sym_f *func, void *cd)
 511 {
 512         Elf *e;
 513         int i, fd;
 514         prmap_t *map;
 515         Elf_Scn *scn, *foundscn = NULL;
 516         Elf_Data *data;
 517         GElf_Ehdr ehdr;
 518         GElf_Shdr shdr;
 519         GElf_Sym sym;
 520         unsigned long stridx = -1;
 521         char *s;
 522         int error = -1;
 523
 524         if ((map = proc_name2map(p, object)) == NULL)
 525                 return (-1);
 526         if ((fd = open(map->pr_mapname, O_RDONLY)) < 0) {
 527                 DPRINTF("ERROR: open %s failed", map->pr_mapname);
 528                 goto err0;
 529         }
 530         if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
 531                 DPRINTFX("ERROR: elf_begin() failed: %s", elf_errmsg(-1));
 532                 goto err1;
 533         }
 534         if (gelf_getehdr(e, &ehdr) == NULL) {
 535                 DPRINTFX("ERROR: gelf_getehdr() failed: %s", elf_errmsg(-1));
 536                 goto err2;
 537         }
 538         /*
 539          * Find the section we are looking for.
 540          */
 541         scn = NULL;
 542         while ((scn = elf_nextscn(e, scn)) != NULL) {
 543                 gelf_getshdr(scn, &shdr);
 544                 if (which == PR_SYMTAB &&
 545                     shdr.sh_type == SHT_SYMTAB) {
 546                         foundscn = scn;
 547                         break;
 548                 } else if (which == PR_DYNSYM &&
 549                     shdr.sh_type == SHT_DYNSYM) {
 550                         foundscn = scn;
 551                         break;
 552                 }
 553         }
 554         if (!foundscn)
 555                 return (-1);
 556         stridx = shdr.sh_link;
 557         if ((data = elf_getdata(foundscn, NULL)) == NULL) {
 558                 DPRINTFX("ERROR: elf_getdata() failed: %s", elf_errmsg(-1));
 559                 goto err2;
 560         }
 561         i = 0;
 562         while (gelf_getsym(data, i++, &sym) != NULL) {
 563                 if (GELF_ST_BIND(sym.st_info) == STB_LOCAL &&
 564                     (mask & BIND_LOCAL) == 0)
 565                         continue;
 566                 if (GELF_ST_BIND(sym.st_info) == STB_GLOBAL &&
 567                     (mask & BIND_GLOBAL) == 0)
 568                         continue;
 569                 if (GELF_ST_BIND(sym.st_info) == STB_WEAK &&
 570                     (mask & BIND_WEAK) == 0)
 571                         continue;
 572                 if (GELF_ST_TYPE(sym.st_info) == STT_NOTYPE &&
 573                     (mask & TYPE_NOTYPE) == 0)
 574                         continue;
 575                 if (GELF_ST_TYPE(sym.st_info) == STT_OBJECT &&
 576                     (mask & TYPE_OBJECT) == 0)
 577                         continue;
 578                 if (GELF_ST_TYPE(sym.st_info) == STT_FUNC &&
 579                     (mask & TYPE_FUNC) == 0)
 580                         continue;
 581                 if (GELF_ST_TYPE(sym.st_info) == STT_SECTION &&
 582                     (mask & TYPE_SECTION) == 0)
 583                         continue;
 584                 if (GELF_ST_TYPE(sym.st_info) == STT_FILE &&
 585                     (mask & TYPE_FILE) == 0)
 586                         continue;
 587                 s = elf_strptr(e, stridx, sym.st_name);
 588                 if (ehdr.e_type != ET_EXEC)
 589                         sym.st_value += map->pr_vaddr;
 590                 (*func)(cd, &sym, s);
 591         }
 592         error = 0;
 593 err2:
 594         elf_end(e);
 595 err1:
 596         close(fd);
 597 err0:
 598         free(map);
 599         return (error);
 600 }