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