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- /* vi: set sw=4 ts=4: */
- /* Run an ELF binary on a linux system.
- Copyright (C) 2002, Steven J. Hill (sjhill@realitydiluted.com)
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
- /* Program to load an ELF binary on a linux system, and run it.
- References to symbols in sharable libraries can be resolved by either
- an ELF sharable library or a linux style of shared library. */
- /* Disclaimer: I have never seen any AT&T source code for SVr4, nor have
- I ever taken any courses on internals. This program was developed using
- information available through the book "UNIX SYSTEM V RELEASE 4,
- Programmers guide: Ansi C and Programming Support Tools", which did
- a more than adequate job of explaining everything required to get this
- working. */
- extern int _dl_linux_resolve(void);
- #define OFFSET_GP_GOT 0x7ff0
- unsigned long _dl_linux_resolver(unsigned long sym_index,
- unsigned long old_gpreg)
- {
- unsigned long *got = (unsigned long *) (old_gpreg - OFFSET_GP_GOT);
- struct elf_resolve *tpnt = (struct elf_resolve *) got[1];
- Elf32_Sym *sym;
- char *strtab;
- unsigned long local_gotno;
- unsigned long gotsym;
- unsigned long value;
- gotsym = tpnt->mips_gotsym;
- local_gotno = tpnt->mips_local_gotno;
- sym = ((Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr)) +
- sym_index;
- strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);
- value = (unsigned long) _dl_find_hash(strtab + sym->st_name,
- tpnt->symbol_scope, tpnt, 1);
- *(got + local_gotno + sym_index - gotsym) = value;
- #ifdef DL_DEBUG
- _dl_dprintf(2, "---RESOLVER---\n");
- _dl_dprintf(2, "SYMTAB INDEX: %i\n", sym_index);
- _dl_dprintf(2, " GOTSYM: %i\n", gotsym);
- _dl_dprintf(2, " LOCAL GOTNO: %i\n", local_gotno);
- _dl_dprintf(2, " VALUE: %x\n", value);
- _dl_dprintf(2, " SYMBOL: %s\n\n", strtab + sym->st_name);
- #endif
- return value;
- }
- void _dl_parse_lazy_relocation_information(struct elf_resolve *tpnt,
- unsigned long rel_addr, unsigned long rel_size, int type)
- {
- /* Nothing to do */
- return;
- }
- int _dl_parse_copy_information(struct dyn_elf *xpnt, unsigned long rel_addr,
- unsigned long rel_size, int type)
- {
- /* Nothing to do */
- return 0;
- }
-
- int _dl_parse_relocation_information(struct elf_resolve *tpnt,
- unsigned long rel_addr, unsigned long rel_size, int type)
- {
- Elf32_Sym *symtab;
- Elf32_Rel *rpnt;
- char *strtab;
- unsigned long *got;
- unsigned long *reloc_addr;
- unsigned long symbol_addr;
- int i, reloc_type, symtab_index;
- /* Now parse the relocation information */
- rel_size = rel_size / sizeof(Elf32_Rel);
- rpnt = (Elf32_Rel *) (rel_addr + tpnt->loadaddr);
- symtab = (Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr);
- strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);
- got = (unsigned long *) (tpnt->dynamic_info[DT_PLTGOT] + tpnt->loadaddr);
- for (i = 0; i < rel_size; i++, rpnt++) {
- reloc_addr = (unsigned long *) (tpnt->loadaddr +
- (unsigned long) rpnt->r_offset);
- reloc_type = ELF32_R_TYPE(rpnt->r_info);
- symtab_index = ELF32_R_SYM(rpnt->r_info);
- symbol_addr = 0;
- if (!symtab_index && tpnt->libtype == program_interpreter)
- continue;
- switch (reloc_type) {
- case R_MIPS_REL32:
- if (symtab_index) {
- if (symtab_index < tpnt->mips_gotsym)
- *reloc_addr +=
- symtab[symtab_index].st_value +
- (unsigned long) tpnt->loadaddr;
- else {
- *reloc_addr += got[symtab_index + tpnt->mips_local_gotno -
- tpnt->mips_gotsym];
- }
- }
- else {
- *reloc_addr += (unsigned long) tpnt->loadaddr;
- }
- break;
- case R_MIPS_NONE:
- break;
- default:
- _dl_dprintf(2, "%s: can't handle reloc type ", _dl_progname);
- if (symtab_index)
- _dl_dprintf(2, "'%s'\n", strtab + symtab[symtab_index].st_name);
- _dl_exit(1);
- };
- };
- return 0;
- }
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