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                                 goto out;
 303                         }
 304                 }
 305         }
 306 symtab:
 307         /*
 308          * Iterate over the Symbols Table to find the symbol.
 309          * Then look up the string name in STRTAB (.dynstr)
 310          */
 311         if (symtabscn == NULL)
 312                 goto err2;
 313         if ((data = elf_getdata(symtabscn, NULL)) == NULL) {
 314                 DPRINTF("ERROR: elf_getdata() failed");
 315                 goto err2;
 316         }
 317         i = 0;
 318         while (gelf_getsym(data, i++, &sym) != NULL) {
 319                 /*
 320                  * Calculate the address mapped to the virtual memory
 321                  * by rtld.
 322                  */
 323                 if (ehdr.e_type != ET_EXEC)
 324                         rsym = map->pr_vaddr + sym.st_value;
 325                 else
 326                         rsym = sym.st_value;
 327                 if (addr >= rsym && addr <= (rsym + sym.st_size)) {
 328                         s = elf_strptr(e, symtabstridx, sym.st_name);
 329                         if (s) {
 330                                 if (s[0] == '_' && s[1] == 'Z' && s[2])
 331                                         demangle(s, name, namesz);
 332                                 else
 333                                         strlcpy(name, s, namesz);
 334                                 memcpy(symcopy, &sym, sizeof(sym));
 335                                 /*
 336                                  * DTrace expects the st_value to contain
 337                                  * only the address relative to the start of
 338                                  * the function.
 339                                  */
 340                                 symcopy->st_value = rsym;
 341                                 error = 0;
 342                                 goto out;
 343                         }
 344                 }
 345         }
 346 out:
 347 err2:
 348         elf_end(e);
 349 err1:
 350         close(fd);
 351 err0:
 352         free(map);
 353         return (error);
 354 }
 355
 356 prmap_t *
 357 proc_name2map(struct proc_handle *p, const char *name)
 358 {
 359         size_t i;
 360         int cnt;
 361         prmap_t *map;
 362         char tmppath[MAXPATHLEN];
 363         struct kinfo_vmentry *kves, *kve;
 364         rd_loadobj_t *rdl;
 365
 366         /*
 367          * If we haven't iterated over the list of loaded objects,
 368          * librtld_db isn't yet initialized and it's very likely
 369          * that librtld_db called us. We need to do the heavy
 370          * lifting here to find the symbol librtld_db is looking for.
 371          */
 372         if (p->nobjs == 0) {
 373                 if ((kves = kinfo_getvmmap(proc_getpid(p), &cnt)) == NULL)
 374                         return (NULL);
 375                 for (i = 0; i < (size_t)cnt; i++) {
 376                         kve = kves + i;
 377                         basename_r(kve->kve_path, tmppath);
 378                         if (strcmp(tmppath, name) == 0) {
 379                                 map = proc_addr2map(p, kve->kve_start);
 380                                 free(kves);
 381                                 return (map);
 382                         }
 383                 }
 384                 free(kves);
 385                 return (NULL);
 386         }
 387         if (name == NULL || strcmp(name, "a.out") == 0) {
 388                 map = proc_addr2map(p, p->rdobjs[0].rdl_saddr);
 389                 return (map);
 390         }
 391         for (i = 0; i < p->nobjs; i++) {
 392                 rdl = &p->rdobjs[i];
 393                 basename_r(rdl->rdl_path, tmppath);
 394                 if (strcmp(tmppath, name) == 0) {
 395                         if ((map = malloc(sizeof(*map))) == NULL)
 396                                 return (NULL);
 397                         proc_rdl2prmap(rdl, map);
 398                         return (map);
 399                 }
 400         }
 401
 402         return (NULL);
 403 }
 404
 405 int
 406 proc_name2sym(struct proc_handle *p, const char *object, const char *symbol,
 407     GElf_Sym *symcopy)
 408 {
 409         Elf *e;
 410         Elf_Scn *scn, *dynsymscn = NULL, *symtabscn = NULL;
 411         Elf_Data *data;
 412         GElf_Shdr shdr;
 413         GElf_Sym sym;
 414         GElf_Ehdr ehdr;
 415         int fd, error = -1;
 416         size_t i;
 417         prmap_t *map;
 418         char *s;
 419         unsigned long symtabstridx = 0, dynsymstridx = 0;
 420
 421         if ((map = proc_name2map(p, object)) == NULL) {
 422                 DPRINTF("ERROR: couldn't find object %s", object);
 423                 goto err0;
 424         }
 425         if ((fd = open(map->pr_mapname, O_RDONLY, 0)) < 0) {
 426                 DPRINTF("ERROR: open %s failed", map->pr_mapname);
 427                 goto err0;
 428         }
 429         if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
 430                 warn("ERROR: elf_begin() failed");
 431                 goto err1;
 432         }
 433         if (gelf_getehdr(e, &ehdr) == NULL) {
 434                 warn("ERROR: gelf_getehdr() failed");
 435                 goto err2;
 436         }
 437         /*
 438          * Find the index of the STRTAB and SYMTAB sections to locate
 439          * symbol names.
 440          */
 441         scn = NULL;
 442         while ((scn = elf_nextscn(e, scn)) != NULL) {
 443                 gelf_getshdr(scn, &shdr);
 444                 switch (shdr.sh_type) {
 445                 case SHT_SYMTAB:
 446                         symtabscn = scn;
 447                         symtabstridx = shdr.sh_link;
 448                         break;
 449                 case SHT_DYNSYM:
 450                         dynsymscn = scn;
 451                         dynsymstridx = shdr.sh_link;
 452                         break;
 453                 default:
 454                         break;
 455                 }
 456         }
 457         /*
 458          * Iterate over the Dynamic Symbols table to find the symbol.
 459          * Then look up the string name in STRTAB (.dynstr)
 460          */
 461         if ((data = elf_getdata(dynsymscn, NULL))) {
 462                 DPRINTF("ERROR: elf_getdata() failed");
 463                 i = 0;
 464                 while (gelf_getsym(data, i++, &sym) != NULL) {
 465                         s = elf_strptr(e, dynsymstridx, sym.st_name);
 466                         if (s && strcmp(s, symbol) == 0) {
 467                                 memcpy(symcopy, &sym, sizeof(sym));
 468                                 symcopy->st_value = map->pr_vaddr + sym.st_value;
 469                                 error = 0;
 470                                 goto out;
 471                         }
 472                 }
 473         }
 474         /*
 475          * Iterate over the Symbols Table to find the symbol.
 476          * Then look up the string name in STRTAB (.dynstr)
 477          */
 478         if (symtabscn == NULL)
 479                 goto err2;
 480         if ((data = elf_getdata(symtabscn, NULL))) {
 481                 i = 0;
 482                 while (gelf_getsym(data, i++, &sym) != NULL) {
 483                         s = elf_strptr(e, symtabstridx, sym.st_name);
 484                         if (s && strcmp(s, symbol) == 0) {
 485                                 memcpy(symcopy, &sym, sizeof(sym));
 486                                 error = 0;
 487                                 goto out;
 488                         }
 489                 }
 490         }
 491 out:
 492 err2:
 493         elf_end(e);
 494 err1:
 495         close(fd);
 496 err0:
 497         free(map);
 498
 499         return (error);
 500 }
 501
 502
 503 int
 504 proc_iter_symbyaddr(struct proc_handle *p, const char *object, int which,
 505     int mask, proc_sym_f *func, void *cd)
 506 {
 507         Elf *e;
 508         int i, fd;
 509         prmap_t *map;
 510         Elf_Scn *scn, *foundscn = NULL;
 511         Elf_Data *data;
 512         GElf_Shdr shdr;
 513         GElf_Sym sym;
 514         unsigned long stridx = -1;
 515         char *s;
 516         int error = -1;
 517
 518         if ((map = proc_name2map(p, object)) == NULL)
 519                 return (-1);
 520         if ((fd = open(map->pr_mapname, O_RDONLY)) < 0) {
 521                 warn("ERROR: open %s failed", map->pr_mapname);
 522                 goto err0;
 523         }
 524         if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
 525                 warn("ERROR: elf_begin() failed");
 526                 goto err1;
 527         }
 528         /*
 529          * Find the section we are looking for.
 530          */
 531         scn = NULL;
 532         while ((scn = elf_nextscn(e, scn)) != NULL) {
 533                 gelf_getshdr(scn, &shdr);
 534                 if (which == PR_SYMTAB &&
 535                     shdr.sh_type == SHT_SYMTAB) {
 536                         foundscn = scn;
 537                         break;
 538                 } else if (which == PR_DYNSYM &&
 539                     shdr.sh_type == SHT_DYNSYM) {
 540                         foundscn = scn;
 541                         break;
 542                 }
 543         }
 544         if (!foundscn)
 545                 return (-1);
 546         stridx = shdr.sh_link;
 547         if ((data = elf_getdata(foundscn, NULL)) == NULL) {
 548                 DPRINTF("ERROR: elf_getdata() failed");
 549                 goto err2;
 550         }
 551         i = 0;
 552         while (gelf_getsym(data, i++, &sym) != NULL) {
 553                 if (GELF_ST_BIND(sym.st_info) == STB_LOCAL &&
 554                     (mask & BIND_LOCAL) == 0)
 555                         continue;
 556                 if (GELF_ST_BIND(sym.st_info) == STB_GLOBAL &&
 557                     (mask & BIND_GLOBAL) == 0)
 558                         continue;
 559                 if (GELF_ST_BIND(sym.st_info) == STB_WEAK &&
 560                     (mask & BIND_WEAK) == 0)
 561                         continue;
 562                 if (GELF_ST_TYPE(sym.st_info) == STT_NOTYPE &&
 563                     (mask & TYPE_NOTYPE) == 0)
 564                         continue;
 565                 if (GELF_ST_TYPE(sym.st_info) == STT_OBJECT &&
 566                     (mask & TYPE_OBJECT) == 0)
 567                         continue;
 568                 if (GELF_ST_TYPE(sym.st_info) == STT_FUNC &&
 569                     (mask & TYPE_FUNC) == 0)
 570                         continue;
 571                 if (GELF_ST_TYPE(sym.st_info) == STT_SECTION &&
 572                     (mask & TYPE_SECTION) == 0)
 573                         continue;
 574                 if (GELF_ST_TYPE(sym.st_info) == STT_FILE &&
 575                     (mask & TYPE_FILE) == 0)
 576                         continue;
 577                 s = elf_strptr(e, stridx, sym.st_name);
 578                 sym.st_value += map->pr_vaddr;
 579                 (*func)(cd, &sym, s);
 580         }
 581         error = 0;
 582 err2:
 583         elf_end(e);
 584 err1:
 585         close(fd);
 586 err0:
 587         free(map);
 588         return (error);
 589 }