2 * Copyright (c) 2000, Boris Popov
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by Boris Popov.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #include <sys/param.h>
36 #include <sys/linker.h>
43 #include <machine/elf.h>
53 struct elf_file *ef_efile;
58 void* ef_fpage; /* First block of the file */
59 int ef_fplen; /* length of first block */
60 Elf_Dyn* ef_dyn; /* Symbol table etc. */
61 Elf_Hashelt ef_nbuckets;
62 Elf_Hashelt ef_nchains;
63 Elf_Hashelt* ef_buckets;
64 Elf_Hashelt* ef_chains;
65 Elf_Hashelt* ef_hashtab;
72 Elf_Phdr * ef_segs[MAXSEGS];
74 Elf_Rel * ef_rel; /* relocation table */
75 int ef_relsz; /* number of entries */
76 Elf_Rela * ef_rela; /* relocation table */
77 int ef_relasz; /* number of entries */
80 static void ef_print_phdr(Elf_Phdr *);
81 static u_long ef_get_offset(elf_file_t, Elf_Off);
82 static int ef_parse_dynamic(elf_file_t);
84 static int ef_get_type(elf_file_t ef);
85 static int ef_close(elf_file_t ef);
86 static int ef_read(elf_file_t ef, Elf_Off offset, size_t len, void* dest);
87 static int ef_read_entry(elf_file_t ef, Elf_Off offset, size_t len, void **ptr);
88 static int ef_seg_read(elf_file_t ef, Elf_Off offset, size_t len, void *dest);
89 static int ef_seg_read_rel(elf_file_t ef, Elf_Off offset, size_t len,
91 static int ef_seg_read_string(elf_file_t ef, Elf_Off offset, size_t len,
93 static int ef_seg_read_entry(elf_file_t ef, Elf_Off offset, size_t len,
95 static int ef_seg_read_entry_rel(elf_file_t ef, Elf_Off offset, size_t len,
97 static Elf_Addr ef_symaddr(elf_file_t ef, Elf_Size symidx);
98 static int ef_lookup_set(elf_file_t ef, const char *name, long *startp,
99 long *stopp, long *countp);
100 static int ef_lookup_symbol(elf_file_t ef, const char* name, Elf_Sym** sym);
102 static struct elf_file_ops ef_file_ops = {
111 ef_seg_read_entry_rel,
118 ef_print_phdr(Elf_Phdr *phdr)
121 if ((phdr->p_flags & PF_W) == 0) {
122 printf("text=0x%lx ", (long)phdr->p_filesz);
124 printf("data=0x%lx", (long)phdr->p_filesz);
125 if (phdr->p_filesz < phdr->p_memsz)
126 printf("+0x%lx", (long)(phdr->p_memsz - phdr->p_filesz));
132 ef_get_offset(elf_file_t ef, Elf_Off off)
137 for (i = 0; i < ef->ef_nsegs; i++) {
139 if (off >= ph->p_vaddr && off < ph->p_vaddr + ph->p_memsz) {
140 return ph->p_offset + (off - ph->p_vaddr);
147 ef_get_type(elf_file_t ef)
150 return (ef->ef_type);
154 * next three functions copied from link_elf.c
157 elf_hash(const char *name)
159 const unsigned char *p = (const unsigned char *) name;
165 if ((g = h & 0xf0000000) != 0)
173 ef_lookup_symbol(elf_file_t ef, const char* name, Elf_Sym** sym)
175 unsigned long symnum;
180 /* First, search hashed global symbols */
181 hash = elf_hash(name);
182 symnum = ef->ef_buckets[hash % ef->ef_nbuckets];
184 while (symnum != STN_UNDEF) {
185 if (symnum >= ef->ef_nchains) {
186 warnx("ef_lookup_symbol: file %s have corrupted symbol table\n",
191 symp = ef->ef_symtab + symnum;
192 if (symp->st_name == 0) {
193 warnx("ef_lookup_symbol: file %s have corrupted symbol table\n",
198 strp = ef->ef_strtab + symp->st_name;
200 if (strcmp(name, strp) == 0) {
201 if (symp->st_shndx != SHN_UNDEF ||
202 (symp->st_value != 0 &&
203 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) {
210 symnum = ef->ef_chains[symnum];
217 ef_lookup_set(elf_file_t ef, const char *name, long *startp, long *stopp,
224 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */
225 setsym = malloc(len);
229 /* get address of first entry */
230 snprintf(setsym, len, "%s%s", "__start_set_", name);
231 error = ef_lookup_symbol(ef, setsym, &sym);
234 *startp = sym->st_value;
236 /* get address of last entry */
237 snprintf(setsym, len, "%s%s", "__stop_set_", name);
238 error = ef_lookup_symbol(ef, setsym, &sym);
241 *stopp = sym->st_value;
243 /* and the number of entries */
244 *countp = (*stopp - *startp) / sizeof(void *);
252 ef_symaddr(elf_file_t ef, Elf_Size symidx)
256 if (symidx >= ef->ef_nchains)
258 sym = ef->ef_symtab + symidx;
260 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL &&
261 sym->st_shndx != SHN_UNDEF && sym->st_value != 0)
262 return (sym->st_value);
267 ef_parse_dynamic(elf_file_t ef)
270 Elf_Hashelt hashhdr[2];
271 /* int plttype = DT_REL;*/
280 rel_off = rela_off = 0;
281 rel_sz = rela_sz = 0;
282 rel_entry = rela_entry = 0;
283 for (dp = ef->ef_dyn; dp->d_tag != DT_NULL; dp++) {
286 error = ef_read(ef, ef_get_offset(ef, dp->d_un.d_ptr),
287 sizeof(hashhdr), hashhdr);
289 warnx("can't read hash header (%lx)",
290 ef_get_offset(ef, dp->d_un.d_ptr));
293 ef->ef_nbuckets = hashhdr[0];
294 ef->ef_nchains = hashhdr[1];
295 error = ef_read_entry(ef, -1,
296 (hashhdr[0] + hashhdr[1]) * sizeof(Elf_Hashelt),
297 (void**)&ef->ef_hashtab);
299 warnx("can't read hash table");
302 ef->ef_buckets = ef->ef_hashtab;
303 ef->ef_chains = ef->ef_buckets + ef->ef_nbuckets;
306 ef->ef_stroff = dp->d_un.d_ptr;
309 ef->ef_strsz = dp->d_un.d_val;
312 ef->ef_symoff = dp->d_un.d_ptr;
315 if (dp->d_un.d_val != sizeof(Elf_Sym))
320 warnx("second DT_REL entry ignored");
321 rel_off = dp->d_un.d_ptr;
325 warnx("second DT_RELSZ entry ignored");
326 rel_sz = dp->d_un.d_val;
330 warnx("second DT_RELENT entry ignored");
331 rel_entry = dp->d_un.d_val;
335 warnx("second DT_RELA entry ignored");
336 rela_off = dp->d_un.d_ptr;
340 warnx("second DT_RELASZ entry ignored");
341 rela_sz = dp->d_un.d_val;
345 warnx("second DT_RELAENT entry ignored");
346 rela_entry = dp->d_un.d_val;
350 if (ef->ef_symoff == 0) {
351 warnx("%s: no .dynsym section found\n", ef->ef_name);
354 if (ef->ef_stroff == 0) {
355 warnx("%s: no .dynstr section found\n", ef->ef_name);
358 if (ef_read_entry(ef, ef_get_offset(ef, ef->ef_symoff),
359 ef->ef_nchains * sizeof(Elf_Sym),
360 (void**)&ef->ef_symtab) != 0) {
362 warnx("%s: can't load .dynsym section (0x%lx)",
363 ef->ef_name, (long)ef->ef_symoff);
366 if (ef_read_entry(ef, ef_get_offset(ef, ef->ef_stroff), ef->ef_strsz,
367 (void**)&ef->ef_strtab) != 0) {
368 warnx("can't load .dynstr section");
372 if (rel_entry == 0) {
373 warnx("%s: no DT_RELENT for DT_REL", ef->ef_name);
376 if (rel_entry != sizeof(Elf_Rel)) {
377 warnx("%s: inconsistent DT_RELENT value",
381 if (rel_sz % rel_entry != 0) {
382 warnx("%s: inconsistent values for DT_RELSZ and "
383 "DT_RELENT", ef->ef_name);
386 if (ef_read_entry(ef, ef_get_offset(ef, rel_off), rel_sz,
387 (void **)&ef->ef_rel) != 0) {
388 warnx("%s: cannot load DT_REL section", ef->ef_name);
391 ef->ef_relsz = rel_sz / rel_entry;
393 warnx("%s: %d REL entries", ef->ef_name,
397 if (rela_entry == 0) {
398 warnx("%s: no DT_RELAENT for DT_RELA", ef->ef_name);
401 if (rela_entry != sizeof(Elf_Rela)) {
402 warnx("%s: inconsistent DT_RELAENT value",
406 if (rela_sz % rela_entry != 0) {
407 warnx("%s: inconsistent values for DT_RELASZ and "
408 "DT_RELAENT", ef->ef_name);
411 if (ef_read_entry(ef, ef_get_offset(ef, rela_off), rela_sz,
412 (void **)&ef->ef_rela) != 0) {
413 warnx("%s: cannot load DT_RELA section", ef->ef_name);
416 ef->ef_relasz = rela_sz / rela_entry;
418 warnx("%s: %d RELA entries", ef->ef_name,
425 ef_read(elf_file_t ef, Elf_Off offset, size_t len, void*dest)
429 if (offset != (Elf_Off)-1) {
430 if (lseek(ef->ef_fd, offset, SEEK_SET) == -1)
434 r = read(ef->ef_fd, dest, len);
435 if (r != -1 && (size_t)r == len)
442 ef_read_entry(elf_file_t ef, Elf_Off offset, size_t len, void**ptr)
449 error = ef_read(ef, offset, len, *ptr);
456 ef_seg_read(elf_file_t ef, Elf_Off offset, size_t len, void*dest)
458 u_long ofs = ef_get_offset(ef, offset);
462 warnx("ef_seg_read(%s): zero offset (%lx:%ld)",
463 ef->ef_name, (long)offset, ofs);
466 return ef_read(ef, ofs, len, dest);
470 ef_seg_read_rel(elf_file_t ef, Elf_Off offset, size_t len, void*dest)
472 u_long ofs = ef_get_offset(ef, offset);
479 warnx("ef_seg_read_rel(%s): zero offset (%lx:%ld)",
480 ef->ef_name, (long)offset, ofs);
483 if ((error = ef_read(ef, ofs, len, dest)) != 0)
486 for (r = ef->ef_rel; r < &ef->ef_rel[ef->ef_relsz]; r++) {
487 error = ef_reloc(ef->ef_efile, r, EF_RELOC_REL, 0, offset, len,
492 for (a = ef->ef_rela; a < &ef->ef_rela[ef->ef_relasz]; a++) {
493 error = ef_reloc(ef->ef_efile, a, EF_RELOC_RELA, 0, offset, len,
502 ef_seg_read_string(elf_file_t ef, Elf_Off offset, size_t len, char *dest)
504 u_long ofs = ef_get_offset(ef, offset);
507 if (ofs == 0 || ofs == (Elf_Off)-1) {
509 warnx("ef_seg_read_string(%s): bad offset (%lx:%ld)",
510 ef->ef_name, (long)offset, ofs);
514 r = pread(ef->ef_fd, dest, len, ofs);
517 if (strnlen(dest, len) == len)
524 ef_seg_read_entry(elf_file_t ef, Elf_Off offset, size_t len, void**ptr)
531 error = ef_seg_read(ef, offset, len, *ptr);
538 ef_seg_read_entry_rel(elf_file_t ef, Elf_Off offset, size_t len, void**ptr)
545 error = ef_seg_read_rel(ef, offset, len, *ptr);
552 ef_open(const char *filename, struct elf_file *efile, int verbose)
560 Elf_Phdr *phdr, *phdyn, *phlimit;
562 if (filename == NULL)
564 if ((fd = open(filename, O_RDONLY)) == -1)
567 ef = malloc(sizeof(*ef));
574 efile->ef_ops = &ef_file_ops;
576 bzero(ef, sizeof(*ef));
577 ef->ef_verbose = verbose;
579 ef->ef_name = strdup(filename);
580 ef->ef_efile = efile;
581 hdr = (Elf_Ehdr *)&ef->ef_hdr;
583 res = read(fd, hdr, sizeof(*hdr));
585 if (res != sizeof(*hdr))
589 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
590 hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
591 hdr->e_ident[EI_VERSION] != EV_CURRENT ||
592 hdr->e_version != EV_CURRENT ||
593 hdr->e_machine != ELF_TARG_MACH ||
594 hdr->e_phentsize != sizeof(Elf_Phdr))
596 phlen = hdr->e_phnum * sizeof(Elf_Phdr);
597 if (ef_read_entry(ef, hdr->e_phoff, phlen,
598 (void**)&ef->ef_ph) != 0)
601 phlimit = phdr + hdr->e_phnum;
604 while (phdr < phlimit) {
607 switch (phdr->p_type) {
610 ef->ef_segs[nsegs] = phdr;
624 warnx("Skipping %s: not dynamically-linked",
627 } else if (nsegs > MAXSEGS) {
628 warnx("%s: too many segments", filename);
631 ef->ef_nsegs = nsegs;
632 if (ef_read_entry(ef, phdyn->p_offset,
633 phdyn->p_filesz, (void**)&ef->ef_dyn) != 0) {
634 printf("ef_read_entry failed\n");
637 error = ef_parse_dynamic(ef);
640 if (hdr->e_type == ET_DYN) {
641 ef->ef_type = EFT_KLD;
642 /* pad = (u_int)dest & PAGE_MASK;
644 dest += PAGE_SIZE - pad;*/
646 } else if (hdr->e_type == ET_EXEC) {
647 /* dest = hdr->e_entry;
650 ef->ef_type = EFT_KERNEL;
661 ef_close(elf_file_t ef)
665 free(ef->ef_fpage);*/
668 ef->ef_efile->ef_ops = NULL;
669 ef->ef_efile->ef_ef = NULL;