/* Run an ELF binary on a linux system. Copyright (C) 1993, Eric Youngdale. Copyright (C) 1995, Andreas Schwab. 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. */ /* Adapted to ELF/68k by Andreas Schwab. */ #ifndef VERBOSE_DLINKER #define VERBOSE_DLINKER #endif #ifdef VERBOSE_DLINKER static char *_dl_reltypes[] = { "R_68K_NONE", "R_68K_32", "R_68K_16", "R_68K_8", "R_68K_PC32", "R_68K_PC16", "R_68K_PC8", "R_68K_GOT32", "R_68K_GOT16", "R_68K_GOT8", "R_68K_GOT32O", "R_68K_GOT16O", "R_68K_GOT8O", "R_68K_PLT32", "R_68K_PLT16", "R_68K_PLT8", "R_68K_PLT32O", "R_68K_PLT16O", "R_68K_PLT8O", "R_68K_COPY", "R_68K_GLOB_DAT", "R_68K_JMP_SLOT", "R_68K_RELATIVE", "R_68K_NUM" }; #endif /* 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. */ #include #include #include /*#include */ #include "string.h" #include #include #include #include "hash.h" #include "linuxelf.h" #include "sysdep.h" #include "../syscall.h" #include "../string.h" extern char *_dl_progname; unsigned int _dl_linux_resolver (int dummy1, int dummy2, struct elf_resolve *tpnt, int reloc_entry) { int reloc_type; struct elf32_rela *this_reloc; char *strtab; struct elf32_sym *symtab; char *rel_addr; int symtab_index; char *new_addr; char **got_addr; unsigned int instr_addr; rel_addr = tpnt->loadaddr + tpnt->dynamic_info[DT_JMPREL]; this_reloc = (struct elf32_rela *) (rel_addr + reloc_entry); reloc_type = ELF32_R_TYPE (this_reloc->r_info); symtab_index = ELF32_R_SYM (this_reloc->r_info); symtab = (struct elf32_sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr); strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr); if (reloc_type != R_68K_JMP_SLOT) { _dl_fdprintf (2, "%s: incorrect relocation type in jump relocations\n", _dl_progname); _dl_exit (1); } /* Address of jump instruction to fix up. */ instr_addr = (int) this_reloc->r_offset + (int) tpnt->loadaddr; got_addr = (char **) instr_addr; #ifdef DEBUG _dl_fdprintf (2, "Resolving symbol %s\n", strtab + symtab[symtab_index].st_name); #endif /* Get the address of the GOT entry. */ new_addr = _dl_find_hash (strtab + symtab[symtab_index].st_name, tpnt->symbol_scope, (int) got_addr, tpnt, 0); if (!new_addr) { _dl_fdprintf (2, "%s: can't resolve symbol '%s'\n", _dl_progname, strtab + symtab[symtab_index].st_name); _dl_exit (1); } /* #define DEBUG_LIBRARY */ #ifdef DEBUG_LIBRARY if ((unsigned int) got_addr < 0x40000000) _dl_fdprintf (2, "Calling library function: %s\n", strtab + symtab[symtab_index].st_name); else #endif *got_addr = new_addr; return (unsigned int) new_addr; } void _dl_parse_lazy_relocation_information (struct elf_resolve *tpnt, int rel_addr, int rel_size, int type) { int i; char *strtab; int reloc_type; int symtab_index; struct elf32_sym *symtab; struct elf32_rela *rpnt; unsigned int *reloc_addr; /* Now parse the relocation information. */ rpnt = (struct elf32_rela *) (rel_addr + tpnt->loadaddr); rel_size = rel_size / sizeof (struct elf32_rela); symtab = (struct elf32_sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr); strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr); for (i = 0; i < rel_size; i++, rpnt++) { reloc_addr = (int *) (tpnt->loadaddr + (int) rpnt->r_offset); reloc_type = ELF32_R_TYPE (rpnt->r_info); symtab_index = ELF32_R_SYM (rpnt->r_info); /* When the dynamic linker bootstrapped itself, it resolved some symbols. Make sure we do not do them again. */ if (tpnt->libtype == program_interpreter && (!symtab_index || _dl_symbol (strtab + symtab[symtab_index].st_name))) continue; switch (reloc_type) { case R_68K_NONE: break; case R_68K_JMP_SLOT: *reloc_addr += (unsigned int) tpnt->loadaddr; break; default: _dl_fdprintf (2, "%s: (LAZY) can't handle reloc type ", _dl_progname); #ifdef VERBOSE_DLINKER _dl_fdprintf (2, "%s ", _dl_reltypes[reloc_type]); #endif if (symtab_index) _dl_fdprintf (2, "'%s'", strtab + symtab[symtab_index].st_name); _dl_fdprintf (2, "\n"); _dl_exit (1); } } } int _dl_parse_relocation_information (struct elf_resolve *tpnt, int rel_addr, int rel_size, int type) { int i; char *strtab; int reloc_type; int goof = 0; struct elf32_sym *symtab; struct elf32_rela *rpnt; unsigned int *reloc_addr; unsigned int symbol_addr; int symtab_index; /* Now parse the relocation information */ rpnt = (struct elf32_rela *) (rel_addr + tpnt->loadaddr); rel_size = rel_size / sizeof (struct elf32_rela); symtab = (struct elf32_sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr); strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr); for (i = 0; i < rel_size; i++, rpnt++) { reloc_addr = (int *) (tpnt->loadaddr + (int) rpnt->r_offset); reloc_type = ELF32_R_TYPE (rpnt->r_info); symtab_index = ELF32_R_SYM (rpnt->r_info); symbol_addr = 0; if (tpnt->libtype == program_interpreter && (!symtab_index || _dl_symbol (strtab + symtab[symtab_index].st_name))) continue; if (symtab_index) { symbol_addr = (unsigned int) _dl_find_hash (strtab + symtab[symtab_index].st_name, tpnt->symbol_scope, (int) reloc_addr, reloc_type == R_68K_JMP_SLOT ? tpnt : NULL, 0); /* We want to allow undefined references to weak symbols - this might have been intentional. We should not be linking local symbols here, so all bases should be covered. */ if (!symbol_addr && ELF32_ST_BIND (symtab[symtab_index].st_info) == STB_GLOBAL) { _dl_fdprintf (2, "%s: can't resolve symbol '%s'\n", _dl_progname, strtab + symtab[symtab_index].st_name); goof++; } } switch (reloc_type) { case R_68K_NONE: break; case R_68K_8: *(char *) reloc_addr = symbol_addr + rpnt->r_addend; break; case R_68K_16: *(short *) reloc_addr = symbol_addr + rpnt->r_addend; break; case R_68K_32: *reloc_addr = symbol_addr + rpnt->r_addend; break; case R_68K_PC8: *(char *) reloc_addr = (symbol_addr + rpnt->r_addend - (unsigned int) reloc_addr); break; case R_68K_PC16: *(short *) reloc_addr = (symbol_addr + rpnt->r_addend - (unsigned int) reloc_addr); break; case R_68K_PC32: *reloc_addr = (symbol_addr + rpnt->r_addend - (unsigned int) reloc_addr); break; case R_68K_GLOB_DAT: case R_68K_JMP_SLOT: *reloc_addr = symbol_addr; break; case R_68K_RELATIVE: *reloc_addr = ((unsigned int) tpnt->loadaddr /* Compatibility kludge. */ + (rpnt->r_addend ? : *reloc_addr)); break; case R_68K_COPY: #if 0 /* Do this later. */ _dl_fdprintf (2, "Doing copy"); if (symtab_index) _dl_fdprintf (2, " for symbol %s", strtab + symtab[symtab_index].st_name); _dl_fdprintf (2, "\n"); _dl_memcpy ((void *) symtab[symtab_index].st_value, (void *) symbol_addr, symtab[symtab_index].st_size); #endif break; default: _dl_fdprintf (2, "%s: can't handle reloc type ", _dl_progname); #ifdef VERBOSE_DLINKER _dl_fdprintf (2, "%s ", _dl_reltypes[reloc_type]); #endif if (symtab_index) _dl_fdprintf (2, "'%s'", strtab + symtab[symtab_index].st_name); _dl_fdprintf (2, "\n"); _dl_exit (1); } } return goof; } /* This is done as a separate step, because there are cases where information is first copied and later initialized. This results in the wrong information being copied. Someone at Sun was complaining about a bug in the handling of _COPY by SVr4, and this may in fact be what he was talking about. Sigh. */ /* No, there are cases where the SVr4 linker fails to emit COPY relocs at all. */ int _dl_parse_copy_information (struct dyn_elf *xpnt, int rel_addr, int rel_size, int type) { int i; char *strtab; int reloc_type; int goof = 0; struct elf32_sym *symtab; struct elf32_rela *rpnt; unsigned int *reloc_addr; unsigned int symbol_addr; struct elf_resolve *tpnt; int symtab_index; /* Now parse the relocation information */ tpnt = xpnt->dyn; rpnt = (struct elf32_rela *) (rel_addr + tpnt->loadaddr); rel_size = rel_size / sizeof (struct elf32_rela); symtab = (struct elf32_sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr); strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr); for (i = 0; i < rel_size; i++, rpnt++) { reloc_addr = (int *) (tpnt->loadaddr + (int) rpnt->r_offset); reloc_type = ELF32_R_TYPE (rpnt->r_info); if (reloc_type != R_68K_COPY) continue; symtab_index = ELF32_R_SYM (rpnt->r_info); symbol_addr = 0; if (tpnt->libtype == program_interpreter && (!symtab_index || _dl_symbol (strtab + symtab[symtab_index].st_name))) continue; if (symtab_index) { symbol_addr = (unsigned int) _dl_find_hash (strtab + symtab[symtab_index].st_name, xpnt->next, (int) reloc_addr, NULL, 1); if (!symbol_addr) { _dl_fdprintf (2, "%s: can't resolve symbol '%s'\n", _dl_progname, strtab + symtab[symtab_index].st_name); goof++; } } if (!goof) _dl_memcpy ((void *) symtab[symtab_index].st_value, (void *) symbol_addr, symtab[symtab_index].st_size); } return goof; }