Annotation of src/usr.bin/nm/elf.c, Revision 1.37
1.37 ! guenther 1: /* $OpenBSD: elf.c,v 1.36 2017/12/09 06:39:04 deraadt Exp $ */
1.1 mickey 2:
3: /*
4: * Copyright (c) 2003 Michael Shalayeff
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: *
16: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19: * IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
20: * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21: * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22: * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24: * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
25: * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
26: * THE POSSIBILITY OF SUCH DAMAGE.
27: */
28:
1.10 mickey 29: #include <sys/mman.h>
30: #include <unistd.h>
31: #include <a.out.h>
1.35 mpi 32: #include <elf.h>
1.10 mickey 33: #include <errno.h>
34: #include <err.h>
1.26 millert 35: #include <stdint.h>
1.10 mickey 36: #include <stdio.h>
37: #include <stdlib.h>
38: #include <string.h>
39: #include <ctype.h>
1.33 miod 40: #include "util.h"
1.10 mickey 41: #include "elfuncs.h"
42:
43: #if ELFSIZE == 32
1.1 mickey 44: #define swap_addr swap32
45: #define swap_off swap32
46: #define swap_sword swap32
47: #define swap_word swap32
48: #define swap_sxword swap32
49: #define swap_xword swap32
50: #define swap_half swap16
51: #define swap_quarter swap16
1.10 mickey 52: #define elf_fix_header elf32_fix_header
53: #define elf_load_shdrs elf32_load_shdrs
54: #define elf_fix_shdrs elf32_fix_shdrs
55: #define elf_fix_sym elf32_fix_sym
56: #define elf_size elf32_size
1.14 kettenis 57: #define elf_symloadx elf32_symloadx
1.10 mickey 58: #define elf_symload elf32_symload
59: #define elf2nlist elf32_2nlist
60: #define elf_shn2type elf32_shn2type
61: #elif ELFSIZE == 64
1.1 mickey 62: #define swap_addr swap64
63: #define swap_off swap64
64: #ifdef __alpha__
65: #define swap_sword swap64
66: #define swap_word swap64
67: #else
68: #define swap_sword swap32
69: #define swap_word swap32
70: #endif
71: #define swap_sxword swap64
72: #define swap_xword swap64
73: #define swap_half swap64
74: #define swap_quarter swap16
1.10 mickey 75: #define elf_fix_header elf64_fix_header
76: #define elf_load_shdrs elf64_load_shdrs
77: #define elf_fix_shdrs elf64_fix_shdrs
78: #define elf_fix_sym elf64_fix_sym
79: #define elf_size elf64_size
1.14 kettenis 80: #define elf_symloadx elf64_symloadx
1.10 mickey 81: #define elf_symload elf64_symload
82: #define elf2nlist elf64_2nlist
83: #define elf_shn2type elf64_shn2type
1.1 mickey 84: #else
85: #error "Unsupported ELF class"
86: #endif
87:
1.9 mickey 88: #define ELF_SDATA ".sdata"
1.20 uwe 89: #define ELF_TDATA ".tdata"
1.3 mickey 90: #define ELF_SBSS ".sbss"
1.20 uwe 91: #define ELF_TBSS ".tbss"
1.6 mickey 92: #define ELF_PLT ".plt"
1.3 mickey 93:
1.11 mickey 94: #ifndef SHN_MIPS_ACOMMON
95: #define SHN_MIPS_ACOMMON SHN_LOPROC + 0
96: #endif
97: #ifndef SHN_MIPS_TEXT
98: #define SHN_MIPS_TEXT SHN_LOPROC + 1
99: #endif
100: #ifndef SHN_MIPS_DATA
101: #define SHN_MIPS_DATA SHN_LOPROC + 2
102: #endif
103: #ifndef SHN_MIPS_SUNDEFINED
104: #define SHN_MIPS_SUNDEFINED SHN_LOPROC + 4
105: #endif
106: #ifndef SHN_MIPS_SCOMMON
107: #define SHN_MIPS_SCOMMON SHN_LOPROC + 3
108: #endif
109:
110: #ifndef STT_PARISC_MILLI
111: #define STT_PARISC_MILLI STT_LOPROC + 0
112: #endif
113:
1.37 ! guenther 114:
! 115: static int elf_fix_header(Elf_Ehdr *);
! 116: static int elf_fix_shdrs(Elf_Ehdr *, Elf_Shdr *);
! 117: static int elf_fix_sym(Elf_Ehdr *, Elf_Sym *);
! 118: static int elf_shn2type(Elf_Ehdr *, u_int _shn, const char *_sn);
! 119: static int elf2nlist(Elf_Sym *, Elf_Ehdr *, Elf_Shdr *, char *_shstr,
! 120: struct xnlist *_np);
! 121: static int elf_symloadx(const char *_name, FILE *, off_t, Elf_Ehdr *,
! 122: Elf_Shdr *, char *_shstr, long _shstrsize, struct xnlist **_pnames,
! 123: struct xnlist ***_psnames, size_t *_pstabsize, int *_pnrawnames,
! 124: const char *_strtab, const char *_symtab);
1.22 deraadt 125:
1.1 mickey 126: int
127: elf_fix_header(Elf_Ehdr *eh)
128: {
129: /* nothing to do */
130: if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
131: return (0);
132:
133: eh->e_type = swap16(eh->e_type);
134: eh->e_machine = swap16(eh->e_machine);
135: eh->e_version = swap32(eh->e_version);
136: eh->e_entry = swap_addr(eh->e_entry);
137: eh->e_phoff = swap_off(eh->e_phoff);
138: eh->e_shoff = swap_off(eh->e_shoff);
139: eh->e_flags = swap32(eh->e_flags);
140: eh->e_ehsize = swap16(eh->e_ehsize);
141: eh->e_phentsize = swap16(eh->e_phentsize);
142: eh->e_phnum = swap16(eh->e_phnum);
143: eh->e_shentsize = swap16(eh->e_shentsize);
144: eh->e_shnum = swap16(eh->e_shnum);
145: eh->e_shstrndx = swap16(eh->e_shstrndx);
146:
147: return (1);
148: }
149:
1.10 mickey 150: Elf_Shdr *
151: elf_load_shdrs(const char *name, FILE *fp, off_t foff, Elf_Ehdr *head)
152: {
153: Elf_Shdr *shdr;
154:
155: elf_fix_header(head);
1.29 semarie 156:
157: if (head->e_shnum == 0) {
158: warnx("%s: no section header table", name);
159: return (NULL);
160: }
161:
162: if (head->e_shstrndx >= head->e_shnum) {
163: warnx("%s: inconsistent section header table", name);
164: return (NULL);
165: }
1.10 mickey 166:
1.31 semarie 167: if (head->e_shentsize < sizeof(Elf_Shdr)) {
168: warnx("%s: inconsistent section header size", name);
169: return (NULL);
170: }
171:
172: if ((shdr = calloc(head->e_shnum, head->e_shentsize)) == NULL) {
1.10 mickey 173: warn("%s: malloc shdr", name);
174: return (NULL);
175: }
176:
177: if (fseeko(fp, foff + head->e_shoff, SEEK_SET)) {
178: warn("%s: fseeko", name);
179: free(shdr);
180: return (NULL);
181: }
182:
183: if (fread(shdr, head->e_shentsize, head->e_shnum, fp) != head->e_shnum) {
184: warnx("%s: premature EOF", name);
185: free(shdr);
186: return (NULL);
187: }
188:
189: elf_fix_shdrs(head, shdr);
190: return (shdr);
1.13 grange 191: }
192:
1.1 mickey 193: int
194: elf_fix_shdrs(Elf_Ehdr *eh, Elf_Shdr *shdr)
195: {
196: int i;
197:
198: /* nothing to do */
199: if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
200: return (0);
201:
202: for (i = eh->e_shnum; i--; shdr++) {
203: shdr->sh_name = swap32(shdr->sh_name);
204: shdr->sh_type = swap32(shdr->sh_type);
205: shdr->sh_flags = swap_xword(shdr->sh_flags);
206: shdr->sh_addr = swap_addr(shdr->sh_addr);
207: shdr->sh_offset = swap_off(shdr->sh_offset);
208: shdr->sh_size = swap_xword(shdr->sh_size);
209: shdr->sh_link = swap32(shdr->sh_link);
210: shdr->sh_info = swap32(shdr->sh_info);
211: shdr->sh_addralign = swap_xword(shdr->sh_addralign);
212: shdr->sh_entsize = swap_xword(shdr->sh_entsize);
213: }
214:
215: return (1);
216: }
217:
218: int
219: elf_fix_sym(Elf_Ehdr *eh, Elf_Sym *sym)
220: {
221: /* nothing to do */
222: if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
223: return (0);
224:
225: sym->st_name = swap32(sym->st_name);
226: sym->st_shndx = swap16(sym->st_shndx);
227: sym->st_value = swap_addr(sym->st_value);
228: sym->st_size = swap_xword(sym->st_size);
229:
230: return (1);
231: }
232:
1.9 mickey 233: int
1.11 mickey 234: elf_shn2type(Elf_Ehdr *eh, u_int shn, const char *sn)
1.9 mickey 235: {
236: switch (shn) {
237: case SHN_MIPS_SUNDEFINED:
1.11 mickey 238: if (eh->e_machine == EM_MIPS)
239: return (N_UNDF | N_EXT);
240: break;
241:
1.9 mickey 242: case SHN_UNDEF:
243: return (N_UNDF | N_EXT);
1.11 mickey 244:
1.9 mickey 245: case SHN_ABS:
246: return (N_ABS);
1.11 mickey 247:
1.9 mickey 248: case SHN_MIPS_ACOMMON:
1.11 mickey 249: if (eh->e_machine == EM_MIPS)
250: return (N_COMM);
251: break;
252:
1.9 mickey 253: case SHN_MIPS_SCOMMON:
1.11 mickey 254: if (eh->e_machine == EM_MIPS)
255: return (N_COMM);
256: break;
257:
1.9 mickey 258: case SHN_COMMON:
259: return (N_COMM);
1.11 mickey 260:
1.9 mickey 261: case SHN_MIPS_TEXT:
1.11 mickey 262: if (eh->e_machine == EM_MIPS)
263: return (N_TEXT);
264: break;
265:
1.9 mickey 266: case SHN_MIPS_DATA:
1.11 mickey 267: if (eh->e_machine == EM_MIPS)
268: return (N_DATA);
269: break;
270:
1.9 mickey 271: default:
1.20 uwe 272: /* TODO: beyond 8 a table-driven binsearch should be used */
1.9 mickey 273: if (sn == NULL)
274: return (-1);
275: else if (!strcmp(sn, ELF_TEXT))
276: return (N_TEXT);
277: else if (!strcmp(sn, ELF_RODATA))
1.36 deraadt 278: return (N_SIZE);
279: else if (!strcmp(sn, ELF_OPENBSDRANDOMDATA))
1.9 mickey 280: return (N_SIZE);
281: else if (!strcmp(sn, ELF_DATA))
282: return (N_DATA);
283: else if (!strcmp(sn, ELF_SDATA))
284: return (N_DATA);
1.20 uwe 285: else if (!strcmp(sn, ELF_TDATA))
286: return (N_DATA);
1.9 mickey 287: else if (!strcmp(sn, ELF_BSS))
288: return (N_BSS);
289: else if (!strcmp(sn, ELF_SBSS))
290: return (N_BSS);
1.20 uwe 291: else if (!strcmp(sn, ELF_TBSS))
292: return (N_BSS);
1.9 mickey 293: else if (!strncmp(sn, ELF_GOT, sizeof(ELF_GOT) - 1))
294: return (N_DATA);
295: else if (!strncmp(sn, ELF_PLT, sizeof(ELF_PLT) - 1))
296: return (N_DATA);
297: }
1.11 mickey 298:
299: return (-1);
1.9 mickey 300: }
301:
1.1 mickey 302: /*
1.33 miod 303: * Devise xnlist's type from Elf_Sym.
1.1 mickey 304: * XXX this task is done as well in libc and kvm_mkdb.
305: */
306: int
1.33 miod 307: elf2nlist(Elf_Sym *sym, Elf_Ehdr *eh, Elf_Shdr *shdr, char *shstr,
308: struct xnlist *np)
1.1 mickey 309: {
1.9 mickey 310: u_char stt;
1.1 mickey 311: const char *sn;
1.9 mickey 312: int type;
1.1 mickey 313:
314: if (sym->st_shndx < eh->e_shnum)
315: sn = shstr + shdr[sym->st_shndx].sh_name;
316: else
1.9 mickey 317: sn = NULL;
1.6 mickey 318: #if 0
319: {
320: extern char *stab;
1.21 miod 321: printf("%d:%s %d %d %s\n", sym->st_shndx, sn? sn : "",
322: ELF_ST_TYPE(sym->st_info), ELF_ST_BIND(sym->st_info),
323: stab + sym->st_name);
1.6 mickey 324: }
325: #endif
1.9 mickey 326:
327: switch (stt = ELF_ST_TYPE(sym->st_info)) {
1.1 mickey 328: case STT_NOTYPE:
1.9 mickey 329: case STT_OBJECT:
1.20 uwe 330: case STT_TLS:
1.11 mickey 331: type = elf_shn2type(eh, sym->st_shndx, sn);
1.9 mickey 332: if (type < 0) {
333: if (sn == NULL)
1.33 miod 334: np->nl.n_other = '?';
1.9 mickey 335: else
1.33 miod 336: np->nl.n_type = stt == STT_NOTYPE ?
337: N_COMM : N_DATA;
1.9 mickey 338: } else {
339: /* a hack for .rodata check (; */
340: if (type == N_SIZE) {
1.33 miod 341: np->nl.n_type = N_DATA;
342: np->nl.n_other = 'r';
1.9 mickey 343: } else
1.33 miod 344: np->nl.n_type = type;
1.8 mickey 345: }
1.21 miod 346: if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
1.33 miod 347: np->nl.n_other = 'W';
1.8 mickey 348: break;
349:
1.1 mickey 350: case STT_FUNC:
1.11 mickey 351: type = elf_shn2type(eh, sym->st_shndx, NULL);
1.33 miod 352: np->nl.n_type = type < 0? N_TEXT : type;
1.1 mickey 353: if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
1.33 miod 354: np->nl.n_other = 'W';
1.14 kettenis 355: } else if (sn != NULL && *sn != 0 &&
1.9 mickey 356: strcmp(sn, ELF_INIT) &&
1.6 mickey 357: strcmp(sn, ELF_TEXT) &&
358: strcmp(sn, ELF_FINI)) /* XXX GNU compat */
1.33 miod 359: np->nl.n_other = '?';
1.1 mickey 360: break;
361:
1.8 mickey 362: case STT_SECTION:
1.11 mickey 363: type = elf_shn2type(eh, sym->st_shndx, NULL);
1.9 mickey 364: if (type < 0)
1.33 miod 365: np->nl.n_other = '?';
1.9 mickey 366: else
1.33 miod 367: np->nl.n_type = type;
1.1 mickey 368: break;
369:
370: case STT_FILE:
1.33 miod 371: np->nl.n_type = N_FN | N_EXT;
1.1 mickey 372: break;
373:
374: case STT_PARISC_MILLI:
1.11 mickey 375: if (eh->e_machine == EM_PARISC)
1.33 miod 376: np->nl.n_type = N_TEXT;
1.11 mickey 377: else
1.33 miod 378: np->nl.n_other = '?';
1.1 mickey 379: break;
1.11 mickey 380:
1.1 mickey 381: default:
1.33 miod 382: np->nl.n_other = '?';
1.1 mickey 383: break;
384: }
1.33 miod 385: if (np->nl.n_type != N_UNDF && ELF_ST_BIND(sym->st_info) != STB_LOCAL) {
386: np->nl.n_type |= N_EXT;
387: if (np->nl.n_other)
388: np->nl.n_other = toupper((unsigned char)np->nl.n_other);
1.10 mickey 389: }
390:
391: return (0);
392: }
393:
394: int
395: elf_size(Elf_Ehdr *head, Elf_Shdr *shdr,
396: u_long *ptext, u_long *pdata, u_long *pbss)
397: {
398: int i;
399:
400: *ptext = *pdata = *pbss = 0;
401:
402: for (i = 0; i < head->e_shnum; i++) {
403: if (!(shdr[i].sh_flags & SHF_ALLOC))
404: ;
405: else if (shdr[i].sh_flags & SHF_EXECINSTR ||
406: !(shdr[i].sh_flags & SHF_WRITE))
407: *ptext += shdr[i].sh_size;
408: else if (shdr[i].sh_type == SHT_NOBITS)
409: *pbss += shdr[i].sh_size;
410: else
411: *pdata += shdr[i].sh_size;
412: }
413:
414: return (0);
415: }
416:
417: int
1.14 kettenis 418: elf_symloadx(const char *name, FILE *fp, off_t foff, Elf_Ehdr *eh,
1.33 miod 419: Elf_Shdr *shdr, char *shstr, long shstrsize, struct xnlist **pnames,
420: struct xnlist ***psnames, size_t *pstabsize, int *pnrawnames,
1.14 kettenis 421: const char *strtab, const char *symtab)
1.10 mickey 422: {
1.14 kettenis 423: long symsize;
1.33 miod 424: struct xnlist *np;
1.10 mickey 425: Elf_Sym sbuf;
426: int i;
427:
428: for (i = 0; i < eh->e_shnum; i++) {
1.30 semarie 429: if (shdr[i].sh_name >= shstrsize) {
430: warnx("%s: corrupt file", name);
431: return (1);
432: }
1.14 kettenis 433: if (!strcmp(shstr + shdr[i].sh_name, strtab)) {
1.10 mickey 434: *pstabsize = shdr[i].sh_size;
1.26 millert 435: if (*pstabsize > SIZE_MAX) {
1.10 mickey 436: warnx("%s: corrupt file", name);
437: return (1);
438: }
439:
440: MMAP(stab, *pstabsize, PROT_READ, MAP_PRIVATE|MAP_FILE,
441: fileno(fp), foff + shdr[i].sh_offset);
1.16 ray 442: if (stab == MAP_FAILED)
1.10 mickey 443: return (1);
444: }
445: }
446: for (i = 0; i < eh->e_shnum; i++) {
1.14 kettenis 447: if (!strcmp(shstr + shdr[i].sh_name, symtab)) {
1.10 mickey 448: symsize = shdr[i].sh_size;
449: if (fseeko(fp, foff + shdr[i].sh_offset, SEEK_SET)) {
450: warn("%s: fseeko", name);
451: if (stab)
452: MUNMAP(stab, *pstabsize);
453: return (1);
454: }
455:
456: *pnrawnames = symsize / sizeof(sbuf);
457: if ((*pnames = calloc(*pnrawnames, sizeof(*np))) == NULL) {
458: warn("%s: malloc names", name);
459: if (stab)
460: MUNMAP(stab, *pstabsize);
1.32 semarie 461: *pnrawnames = 0;
1.10 mickey 462: return (1);
463: }
1.18 deraadt 464: if ((*psnames = calloc(*pnrawnames, sizeof(np))) == NULL) {
1.10 mickey 465: warn("%s: malloc snames", name);
466: if (stab)
467: MUNMAP(stab, *pstabsize);
468: free(*pnames);
1.32 semarie 469: *pnames = NULL;
470: *pnrawnames = 0;
1.10 mickey 471: return (1);
472: }
473:
474: for (np = *pnames; symsize > 0; symsize -= sizeof(sbuf)) {
475: if (fread(&sbuf, 1, sizeof(sbuf),
476: fp) != sizeof(sbuf)) {
477: warn("%s: read symbol", name);
478: if (stab)
479: MUNMAP(stab, *pstabsize);
480: free(*pnames);
481: free(*psnames);
1.32 semarie 482: *pnames = NULL;
483: *psnames = NULL;
484: *pnrawnames = 0;
1.10 mickey 485: return (1);
486: }
487:
488: elf_fix_sym(eh, &sbuf);
489:
1.15 mickey 490: if (!sbuf.st_name ||
491: sbuf.st_name > *pstabsize)
1.10 mickey 492: continue;
493:
494: elf2nlist(&sbuf, eh, shdr, shstr, np);
1.33 miod 495: np->nl.n_value = sbuf.st_value;
496: np->nl.n_un.n_strx = sbuf.st_name;
497: np->n_size = sbuf.st_size;
1.10 mickey 498: np++;
499: }
500: *pnrawnames = np - *pnames;
501: }
1.14 kettenis 502: }
1.22 deraadt 503: return (0);
1.14 kettenis 504: }
505:
506: int
507: elf_symload(const char *name, FILE *fp, off_t foff, Elf_Ehdr *eh,
1.33 miod 508: Elf_Shdr *shdr, struct xnlist **pnames, struct xnlist ***psnames,
1.14 kettenis 509: size_t *pstabsize, int *pnrawnames)
510: {
511: long shstrsize;
512: char *shstr;
513:
514: shstrsize = shdr[eh->e_shstrndx].sh_size;
1.17 miod 515: if (shstrsize == 0) {
516: warnx("%s: no name list", name);
517: return (1);
518: }
519:
1.14 kettenis 520: if ((shstr = malloc(shstrsize)) == NULL) {
521: warn("%s: malloc shsrt", name);
522: return (1);
523: }
524:
525: if (fseeko(fp, foff + shdr[eh->e_shstrndx].sh_offset, SEEK_SET)) {
526: warn("%s: fseeko", name);
527: free(shstr);
528: return (1);
529: }
530:
531: if (fread(shstr, 1, shstrsize, fp) != shstrsize) {
532: warnx("%s: premature EOF", name);
533: free(shstr);
534: return(1);
535: }
536:
537: stab = NULL;
1.25 miod 538: *pnames = NULL; *psnames = NULL; *pnrawnames = 0;
1.28 guenther 539: if (!dynamic_only) {
1.30 semarie 540: elf_symloadx(name, fp, foff, eh, shdr, shstr, shstrsize, pnames,
1.28 guenther 541: psnames, pstabsize, pnrawnames, ELF_STRTAB, ELF_SYMTAB);
542: }
1.14 kettenis 543: if (stab == NULL) {
1.30 semarie 544: elf_symloadx(name, fp, foff, eh, shdr, shstr, shstrsize, pnames,
1.14 kettenis 545: psnames, pstabsize, pnrawnames, ELF_DYNSTR, ELF_DYNSYM);
1.10 mickey 546: }
547:
548: free(shstr);
549: if (stab == NULL) {
550: warnx("%s: no name list", name);
1.34 mmcc 551: free(*pnames);
552: free(*psnames);
1.10 mickey 553: return (1);
1.1 mickey 554: }
555:
556: return (0);
557: }
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