diff options
Diffstat (limited to 'ldso/ldso/i386/elfinterp.c')
| -rw-r--r-- | ldso/ldso/i386/elfinterp.c | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/ldso/ldso/i386/elfinterp.c b/ldso/ldso/i386/elfinterp.c new file mode 100644 index 000000000..3347882d6 --- /dev/null +++ b/ldso/ldso/i386/elfinterp.c @@ -0,0 +1,321 @@ +/* Run an ELF binary on a linux system. + + Copyright (C) 1993, Eric Youngdale. + + 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. */ + +#ifndef VERBOSE_DLINKER +#define VERBOSE_DLINKER +#endif +#ifdef VERBOSE_DLINKER +static char * _dl_reltypes[] = {"R_386_NONE","R_386_32","R_386_PC32","R_386_GOT32", + "R_386_PLT32","R_386_COPY","R_386_GLOB_DAT", + "R_386_JMP_SLOT","R_386_RELATIVE","R_386_GOTOFF", + "R_386_GOTPC","R_386_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 <sys/types.h> +#include <errno.h> +#include <fcntl.h> +#include <linux/elf.h> + +#include "hash.h" +#include "linuxelf.h" +#include "../string.h" +#include "../syscall.h" + +#define SVR4_COMPATIBILITY + +extern char *_dl_progname; + +extern int _dl_linux_resolve(void); + +unsigned int _dl_linux_resolver(int dummy, int i) +{ + unsigned int * sp; + int reloc_entry; + int reloc_type; + struct elf32_rel * this_reloc; + char * strtab; + struct elf32_sym * symtab; + struct elf32_rel * rel_addr; + struct elf_resolve * tpnt; + int symtab_index; + char * new_addr; + char ** got_addr; + unsigned int instr_addr; + sp = &i; + reloc_entry = sp[1]; + tpnt = (struct elf_resolve *) sp[0]; + + rel_addr = (struct elf32_rel *) (tpnt->dynamic_info[DT_JMPREL] + + tpnt->loadaddr); + + this_reloc = rel_addr + (reloc_entry >> 3); + 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_386_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 { + *got_addr = new_addr; + } +#else + *got_addr = new_addr; +#endif + 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_rel * rpnt; + unsigned int * reloc_addr; + + /* Now parse the relocation information */ + rpnt = (struct elf32_rel *) (rel_addr + tpnt->loadaddr); + rel_size = rel_size / sizeof(struct elf32_rel); + + 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(!symtab_index && tpnt->libtype == program_interpreter) continue; + if(symtab_index && tpnt->libtype == program_interpreter && + _dl_symbol(strtab + symtab[symtab_index].st_name)) + continue; + + switch(reloc_type){ + case R_386_NONE: break; + case R_386_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'\n", + strtab + symtab[symtab_index].st_name); + _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_rel * rpnt; + unsigned int * reloc_addr; + unsigned int symbol_addr; + int symtab_index; + /* Now parse the relocation information */ + + rpnt = (struct elf32_rel *) (rel_addr + tpnt->loadaddr); + rel_size = rel_size / sizeof(struct elf32_rel); + + 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(!symtab_index && tpnt->libtype == program_interpreter) continue; + + if(symtab_index) { + + if(tpnt->libtype == program_interpreter && + _dl_symbol(strtab + symtab[symtab_index].st_name)) + continue; + + symbol_addr = (unsigned int) + _dl_find_hash(strtab + symtab[symtab_index].st_name, + tpnt->symbol_scope, (int) reloc_addr, + (reloc_type == R_386_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_386_NONE: + break; + case R_386_32: + *reloc_addr += symbol_addr; + break; + case R_386_PC32: + *reloc_addr += symbol_addr - (unsigned int) reloc_addr; + break; + case R_386_GLOB_DAT: + case R_386_JMP_SLOT: + *reloc_addr = symbol_addr; + break; + case R_386_RELATIVE: + *reloc_addr += (unsigned int) tpnt->loadaddr; + break; + case R_386_COPY: +#if 0 /* Do this later */ + _dl_fdprintf(2, "Doing copy for symbol "); + if(symtab_index) _dl_fdprintf(2, 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'\n", strtab + symtab[symtab_index].st_name); + _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_rel * 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_rel *) (rel_addr + tpnt->loadaddr); + rel_size = rel_size / sizeof(struct elf32_rel); + + 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_386_COPY) continue; + symtab_index = ELF32_R_SYM(rpnt->r_info); + symbol_addr = 0; + if(!symtab_index && tpnt->libtype == program_interpreter) continue; + if(symtab_index) { + + if(tpnt->libtype == program_interpreter && + _dl_symbol(strtab + symtab[symtab_index].st_name)) + continue; + + 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((char *) symtab[symtab_index].st_value, + (char *) symbol_addr, + symtab[symtab_index].st_size); + }; + return goof; +} + + |