Annotation of src/usr.bin/nm/elf.c, Revision 1.24
1.24 ! deraadt 1: /* $OpenBSD: elf.c,v 1.23 2013/11/26 13:19:07 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>
32: #include <elf_abi.h>
33: #include <errno.h>
34: #include <err.h>
35: #include <stdio.h>
36: #include <stdlib.h>
37: #include <string.h>
1.24 ! deraadt 38: #include <limits.h>
1.10 mickey 39: #include <ctype.h>
40: #include "elfuncs.h"
41: #include "util.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
1.13 grange 54: #define elf_load_phdrs elf32_load_phdrs
1.10 mickey 55: #define elf_fix_shdrs elf32_fix_shdrs
56: #define elf_fix_phdrs elf32_fix_phdrs
57: #define elf_fix_sym elf32_fix_sym
58: #define elf_size elf32_size
1.14 kettenis 59: #define elf_symloadx elf32_symloadx
1.10 mickey 60: #define elf_symload elf32_symload
61: #define elf2nlist elf32_2nlist
62: #define elf_shn2type elf32_shn2type
63: #elif ELFSIZE == 64
1.1 mickey 64: #define swap_addr swap64
65: #define swap_off swap64
66: #ifdef __alpha__
67: #define swap_sword swap64
68: #define swap_word swap64
69: #else
70: #define swap_sword swap32
71: #define swap_word swap32
72: #endif
73: #define swap_sxword swap64
74: #define swap_xword swap64
75: #define swap_half swap64
76: #define swap_quarter swap16
1.10 mickey 77: #define elf_fix_header elf64_fix_header
78: #define elf_load_shdrs elf64_load_shdrs
1.13 grange 79: #define elf_load_phdrs elf64_load_phdrs
1.10 mickey 80: #define elf_fix_shdrs elf64_fix_shdrs
81: #define elf_fix_phdrs elf64_fix_phdrs
82: #define elf_fix_sym elf64_fix_sym
83: #define elf_size elf64_size
1.14 kettenis 84: #define elf_symloadx elf64_symloadx
1.10 mickey 85: #define elf_symload elf64_symload
86: #define elf2nlist elf64_2nlist
87: #define elf_shn2type elf64_shn2type
1.1 mickey 88: #else
89: #error "Unsupported ELF class"
90: #endif
91:
1.9 mickey 92: #define ELF_SDATA ".sdata"
1.20 uwe 93: #define ELF_TDATA ".tdata"
1.3 mickey 94: #define ELF_SBSS ".sbss"
1.20 uwe 95: #define ELF_TBSS ".tbss"
1.6 mickey 96: #define ELF_PLT ".plt"
1.3 mickey 97:
1.11 mickey 98: #ifndef SHN_MIPS_ACOMMON
99: #define SHN_MIPS_ACOMMON SHN_LOPROC + 0
100: #endif
101: #ifndef SHN_MIPS_TEXT
102: #define SHN_MIPS_TEXT SHN_LOPROC + 1
103: #endif
104: #ifndef SHN_MIPS_DATA
105: #define SHN_MIPS_DATA SHN_LOPROC + 2
106: #endif
107: #ifndef SHN_MIPS_SUNDEFINED
108: #define SHN_MIPS_SUNDEFINED SHN_LOPROC + 4
109: #endif
110: #ifndef SHN_MIPS_SCOMMON
111: #define SHN_MIPS_SCOMMON SHN_LOPROC + 3
112: #endif
113:
114: #ifndef STT_PARISC_MILLI
115: #define STT_PARISC_MILLI STT_LOPROC + 0
116: #endif
117:
1.22 deraadt 118: int elf_shn2type(Elf_Ehdr *, u_int, const char *);
119: int elf2nlist(Elf_Sym *, Elf_Ehdr *, Elf_Shdr *, char *, struct nlist *);
120:
1.1 mickey 121: int
122: elf_fix_header(Elf_Ehdr *eh)
123: {
124: /* nothing to do */
125: if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
126: return (0);
127:
128: eh->e_type = swap16(eh->e_type);
129: eh->e_machine = swap16(eh->e_machine);
130: eh->e_version = swap32(eh->e_version);
131: eh->e_entry = swap_addr(eh->e_entry);
132: eh->e_phoff = swap_off(eh->e_phoff);
133: eh->e_shoff = swap_off(eh->e_shoff);
134: eh->e_flags = swap32(eh->e_flags);
135: eh->e_ehsize = swap16(eh->e_ehsize);
136: eh->e_phentsize = swap16(eh->e_phentsize);
137: eh->e_phnum = swap16(eh->e_phnum);
138: eh->e_shentsize = swap16(eh->e_shentsize);
139: eh->e_shnum = swap16(eh->e_shnum);
140: eh->e_shstrndx = swap16(eh->e_shstrndx);
141:
142: return (1);
143: }
144:
1.10 mickey 145: Elf_Shdr *
146: elf_load_shdrs(const char *name, FILE *fp, off_t foff, Elf_Ehdr *head)
147: {
148: Elf_Shdr *shdr;
149:
150: elf_fix_header(head);
151:
1.18 deraadt 152: if ((shdr = calloc(head->e_shentsize, head->e_shnum)) == NULL) {
1.10 mickey 153: warn("%s: malloc shdr", name);
154: return (NULL);
155: }
156:
157: if (fseeko(fp, foff + head->e_shoff, SEEK_SET)) {
158: warn("%s: fseeko", name);
159: free(shdr);
160: return (NULL);
161: }
162:
163: if (fread(shdr, head->e_shentsize, head->e_shnum, fp) != head->e_shnum) {
164: warnx("%s: premature EOF", name);
165: free(shdr);
166: return (NULL);
167: }
168:
169: elf_fix_shdrs(head, shdr);
170: return (shdr);
1.13 grange 171: }
172:
173: Elf_Phdr *
174: elf_load_phdrs(const char *name, FILE *fp, off_t foff, Elf_Ehdr *head)
175: {
176: Elf_Phdr *phdr;
177:
1.18 deraadt 178: if ((phdr = calloc(head->e_phentsize, head->e_phnum)) == NULL) {
1.13 grange 179: warn("%s: malloc phdr", name);
180: return (NULL);
181: }
182:
183: if (fseeko(fp, foff + head->e_phoff, SEEK_SET)) {
184: warn("%s: fseeko", name);
185: free(phdr);
186: return (NULL);
187: }
188:
189: if (fread(phdr, head->e_phentsize, head->e_phnum, fp) != head->e_phnum) {
190: warnx("%s: premature EOF", name);
191: free(phdr);
192: return (NULL);
193: }
194:
195: elf_fix_phdrs(head, phdr);
196: return (phdr);
1.10 mickey 197: }
198:
1.1 mickey 199: int
200: elf_fix_shdrs(Elf_Ehdr *eh, Elf_Shdr *shdr)
201: {
202: int i;
203:
204: /* nothing to do */
205: if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
206: return (0);
207:
208: for (i = eh->e_shnum; i--; shdr++) {
209: shdr->sh_name = swap32(shdr->sh_name);
210: shdr->sh_type = swap32(shdr->sh_type);
211: shdr->sh_flags = swap_xword(shdr->sh_flags);
212: shdr->sh_addr = swap_addr(shdr->sh_addr);
213: shdr->sh_offset = swap_off(shdr->sh_offset);
214: shdr->sh_size = swap_xword(shdr->sh_size);
215: shdr->sh_link = swap32(shdr->sh_link);
216: shdr->sh_info = swap32(shdr->sh_info);
217: shdr->sh_addralign = swap_xword(shdr->sh_addralign);
218: shdr->sh_entsize = swap_xword(shdr->sh_entsize);
219: }
220:
221: return (1);
222: }
223:
224: int
225: elf_fix_phdrs(Elf_Ehdr *eh, Elf_Phdr *phdr)
226: {
227: int i;
228:
229: /* nothing to do */
230: if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
231: return (0);
232:
233: for (i = eh->e_phnum; i--; phdr++) {
234: phdr->p_type = swap32(phdr->p_type);
235: phdr->p_flags = swap32(phdr->p_flags);
236: phdr->p_offset = swap_off(phdr->p_offset);
237: phdr->p_vaddr = swap_addr(phdr->p_vaddr);
238: phdr->p_paddr = swap_addr(phdr->p_paddr);
239: phdr->p_filesz = swap_xword(phdr->p_filesz);
240: phdr->p_memsz = swap_xword(phdr->p_memsz);
241: phdr->p_align = swap_xword(phdr->p_align);
242: }
243:
244: return (1);
245: }
246:
247: int
248: elf_fix_sym(Elf_Ehdr *eh, Elf_Sym *sym)
249: {
250: /* nothing to do */
251: if (eh->e_ident[EI_DATA] == ELF_TARG_DATA)
252: return (0);
253:
254: sym->st_name = swap32(sym->st_name);
255: sym->st_shndx = swap16(sym->st_shndx);
256: sym->st_value = swap_addr(sym->st_value);
257: sym->st_size = swap_xword(sym->st_size);
258:
259: return (1);
260: }
261:
1.9 mickey 262: int
1.11 mickey 263: elf_shn2type(Elf_Ehdr *eh, u_int shn, const char *sn)
1.9 mickey 264: {
265: switch (shn) {
266: case SHN_MIPS_SUNDEFINED:
1.11 mickey 267: if (eh->e_machine == EM_MIPS)
268: return (N_UNDF | N_EXT);
269: break;
270:
1.9 mickey 271: case SHN_UNDEF:
272: return (N_UNDF | N_EXT);
1.11 mickey 273:
1.9 mickey 274: case SHN_ABS:
275: return (N_ABS);
1.11 mickey 276:
1.9 mickey 277: case SHN_MIPS_ACOMMON:
1.11 mickey 278: if (eh->e_machine == EM_MIPS)
279: return (N_COMM);
280: break;
281:
1.9 mickey 282: case SHN_MIPS_SCOMMON:
1.11 mickey 283: if (eh->e_machine == EM_MIPS)
284: return (N_COMM);
285: break;
286:
1.9 mickey 287: case SHN_COMMON:
288: return (N_COMM);
1.11 mickey 289:
1.9 mickey 290: case SHN_MIPS_TEXT:
1.11 mickey 291: if (eh->e_machine == EM_MIPS)
292: return (N_TEXT);
293: break;
294:
1.9 mickey 295: case SHN_MIPS_DATA:
1.11 mickey 296: if (eh->e_machine == EM_MIPS)
297: return (N_DATA);
298: break;
299:
1.9 mickey 300: default:
1.20 uwe 301: /* TODO: beyond 8 a table-driven binsearch should be used */
1.9 mickey 302: if (sn == NULL)
303: return (-1);
304: else if (!strcmp(sn, ELF_TEXT))
305: return (N_TEXT);
306: else if (!strcmp(sn, ELF_RODATA))
307: return (N_SIZE);
308: else if (!strcmp(sn, ELF_DATA))
309: return (N_DATA);
310: else if (!strcmp(sn, ELF_SDATA))
311: return (N_DATA);
1.20 uwe 312: else if (!strcmp(sn, ELF_TDATA))
313: return (N_DATA);
1.9 mickey 314: else if (!strcmp(sn, ELF_BSS))
315: return (N_BSS);
316: else if (!strcmp(sn, ELF_SBSS))
317: return (N_BSS);
1.20 uwe 318: else if (!strcmp(sn, ELF_TBSS))
319: return (N_BSS);
1.9 mickey 320: else if (!strncmp(sn, ELF_GOT, sizeof(ELF_GOT) - 1))
321: return (N_DATA);
322: else if (!strncmp(sn, ELF_PLT, sizeof(ELF_PLT) - 1))
323: return (N_DATA);
324: }
1.11 mickey 325:
326: return (-1);
1.9 mickey 327: }
328:
1.1 mickey 329: /*
330: * Devise nlist's type from Elf_Sym.
331: * XXX this task is done as well in libc and kvm_mkdb.
332: */
333: int
334: elf2nlist(Elf_Sym *sym, Elf_Ehdr *eh, Elf_Shdr *shdr, char *shstr, struct nlist *np)
335: {
1.9 mickey 336: u_char stt;
1.1 mickey 337: const char *sn;
1.9 mickey 338: int type;
1.1 mickey 339:
340: if (sym->st_shndx < eh->e_shnum)
341: sn = shstr + shdr[sym->st_shndx].sh_name;
342: else
1.9 mickey 343: sn = NULL;
1.6 mickey 344: #if 0
345: {
346: extern char *stab;
1.21 miod 347: printf("%d:%s %d %d %s\n", sym->st_shndx, sn? sn : "",
348: ELF_ST_TYPE(sym->st_info), ELF_ST_BIND(sym->st_info),
349: stab + sym->st_name);
1.6 mickey 350: }
351: #endif
1.9 mickey 352:
353: switch (stt = ELF_ST_TYPE(sym->st_info)) {
1.1 mickey 354: case STT_NOTYPE:
1.9 mickey 355: case STT_OBJECT:
1.20 uwe 356: case STT_TLS:
1.11 mickey 357: type = elf_shn2type(eh, sym->st_shndx, sn);
1.9 mickey 358: if (type < 0) {
359: if (sn == NULL)
360: np->n_other = '?';
361: else
362: np->n_type = stt == STT_NOTYPE? N_COMM : N_DATA;
363: } else {
364: /* a hack for .rodata check (; */
365: if (type == N_SIZE) {
1.1 mickey 366: np->n_type = N_DATA;
1.8 mickey 367: np->n_other = 'r';
1.9 mickey 368: } else
369: np->n_type = type;
1.8 mickey 370: }
1.21 miod 371: if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
372: np->n_other = 'W';
1.8 mickey 373: break;
374:
1.1 mickey 375: case STT_FUNC:
1.11 mickey 376: type = elf_shn2type(eh, sym->st_shndx, NULL);
1.9 mickey 377: np->n_type = type < 0? N_TEXT : type;
1.1 mickey 378: if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
379: np->n_type = N_INDR;
380: np->n_other = 'W';
1.14 kettenis 381: } else if (sn != NULL && *sn != 0 &&
1.9 mickey 382: strcmp(sn, ELF_INIT) &&
1.6 mickey 383: strcmp(sn, ELF_TEXT) &&
384: strcmp(sn, ELF_FINI)) /* XXX GNU compat */
1.1 mickey 385: np->n_other = '?';
386: break;
387:
1.8 mickey 388: case STT_SECTION:
1.11 mickey 389: type = elf_shn2type(eh, sym->st_shndx, NULL);
1.9 mickey 390: if (type < 0)
1.8 mickey 391: np->n_other = '?';
1.9 mickey 392: else
393: np->n_type = type;
1.1 mickey 394: break;
395:
396: case STT_FILE:
397: np->n_type = N_FN | N_EXT;
398: break;
399:
400: case STT_PARISC_MILLI:
1.11 mickey 401: if (eh->e_machine == EM_PARISC)
402: np->n_type = N_TEXT;
403: else
404: np->n_other = '?';
1.1 mickey 405: break;
1.11 mickey 406:
1.1 mickey 407: default:
408: np->n_other = '?';
409: break;
410: }
411: if (np->n_type != N_UNDF && ELF_ST_BIND(sym->st_info) != STB_LOCAL) {
412: np->n_type |= N_EXT;
413: if (np->n_other)
1.23 deraadt 414: np->n_other = toupper((unsigned char)np->n_other);
1.10 mickey 415: }
416:
417: return (0);
418: }
419:
420: int
421: elf_size(Elf_Ehdr *head, Elf_Shdr *shdr,
422: u_long *ptext, u_long *pdata, u_long *pbss)
423: {
424: int i;
425:
426: *ptext = *pdata = *pbss = 0;
427:
428: for (i = 0; i < head->e_shnum; i++) {
429: if (!(shdr[i].sh_flags & SHF_ALLOC))
430: ;
431: else if (shdr[i].sh_flags & SHF_EXECINSTR ||
432: !(shdr[i].sh_flags & SHF_WRITE))
433: *ptext += shdr[i].sh_size;
434: else if (shdr[i].sh_type == SHT_NOBITS)
435: *pbss += shdr[i].sh_size;
436: else
437: *pdata += shdr[i].sh_size;
438: }
439:
440: return (0);
441: }
442:
443: int
1.14 kettenis 444: elf_symloadx(const char *name, FILE *fp, off_t foff, Elf_Ehdr *eh,
445: Elf_Shdr *shdr, char *shstr, struct nlist **pnames,
446: struct nlist ***psnames, size_t *pstabsize, int *pnrawnames,
447: const char *strtab, const char *symtab)
1.10 mickey 448: {
1.14 kettenis 449: long symsize;
1.10 mickey 450: struct nlist *np;
451: Elf_Sym sbuf;
452: int i;
453:
454: for (i = 0; i < eh->e_shnum; i++) {
1.14 kettenis 455: if (!strcmp(shstr + shdr[i].sh_name, strtab)) {
1.10 mickey 456: *pstabsize = shdr[i].sh_size;
457: if (*pstabsize > SIZE_T_MAX) {
458: warnx("%s: corrupt file", name);
459: return (1);
460: }
461:
462: MMAP(stab, *pstabsize, PROT_READ, MAP_PRIVATE|MAP_FILE,
463: fileno(fp), foff + shdr[i].sh_offset);
1.16 ray 464: if (stab == MAP_FAILED)
1.10 mickey 465: return (1);
466: }
467: }
468: for (i = 0; i < eh->e_shnum; i++) {
1.14 kettenis 469: if (!strcmp(shstr + shdr[i].sh_name, symtab)) {
1.10 mickey 470: symsize = shdr[i].sh_size;
471: if (fseeko(fp, foff + shdr[i].sh_offset, SEEK_SET)) {
472: warn("%s: fseeko", name);
473: if (stab)
474: MUNMAP(stab, *pstabsize);
475: return (1);
476: }
477:
478: *pnrawnames = symsize / sizeof(sbuf);
479: if ((*pnames = calloc(*pnrawnames, sizeof(*np))) == NULL) {
480: warn("%s: malloc names", name);
481: if (stab)
482: MUNMAP(stab, *pstabsize);
483: return (1);
484: }
1.18 deraadt 485: if ((*psnames = calloc(*pnrawnames, sizeof(np))) == NULL) {
1.10 mickey 486: warn("%s: malloc snames", name);
487: if (stab)
488: MUNMAP(stab, *pstabsize);
489: free(*pnames);
490: return (1);
491: }
492:
493: for (np = *pnames; symsize > 0; symsize -= sizeof(sbuf)) {
494: if (fread(&sbuf, 1, sizeof(sbuf),
495: fp) != sizeof(sbuf)) {
496: warn("%s: read symbol", name);
497: if (stab)
498: MUNMAP(stab, *pstabsize);
499: free(*pnames);
500: free(*psnames);
501: return (1);
502: }
503:
504: elf_fix_sym(eh, &sbuf);
505:
1.15 mickey 506: if (!sbuf.st_name ||
507: sbuf.st_name > *pstabsize)
1.10 mickey 508: continue;
509:
510: elf2nlist(&sbuf, eh, shdr, shstr, np);
511: np->n_value = sbuf.st_value;
512: np->n_un.n_strx = sbuf.st_name;
513: np++;
514: }
515: *pnrawnames = np - *pnames;
516: }
1.14 kettenis 517: }
1.22 deraadt 518: return (0);
1.14 kettenis 519: }
520:
521: int
522: elf_symload(const char *name, FILE *fp, off_t foff, Elf_Ehdr *eh,
523: Elf_Shdr *shdr, struct nlist **pnames, struct nlist ***psnames,
524: size_t *pstabsize, int *pnrawnames)
525: {
526: long shstrsize;
527: char *shstr;
528:
529: shstrsize = shdr[eh->e_shstrndx].sh_size;
1.17 miod 530: if (shstrsize == 0) {
531: warnx("%s: no name list", name);
532: return (1);
533: }
534:
1.14 kettenis 535: if ((shstr = malloc(shstrsize)) == NULL) {
536: warn("%s: malloc shsrt", name);
537: return (1);
538: }
539:
540: if (fseeko(fp, foff + shdr[eh->e_shstrndx].sh_offset, SEEK_SET)) {
541: warn("%s: fseeko", name);
542: free(shstr);
543: return (1);
544: }
545:
546: if (fread(shstr, 1, shstrsize, fp) != shstrsize) {
547: warnx("%s: premature EOF", name);
548: free(shstr);
549: return(1);
550: }
551:
552: stab = NULL;
553: *pnames = NULL; *psnames = NULL;
554: elf_symloadx(name, fp, foff, eh, shdr, shstr, pnames,
555: psnames, pstabsize, pnrawnames, ELF_STRTAB, ELF_SYMTAB);
556: if (stab == NULL) {
557: elf_symloadx(name, fp, foff, eh, shdr, shstr, pnames,
558: psnames, pstabsize, pnrawnames, ELF_DYNSTR, ELF_DYNSYM);
1.10 mickey 559: }
560:
561: free(shstr);
562: if (stab == NULL) {
563: warnx("%s: no name list", name);
564: if (*pnames)
565: free(*pnames);
566: if (*psnames)
567: free(*psnames);
568: return (1);
1.1 mickey 569: }
570:
571: return (0);
572: }
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