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Diffstat (limited to 'ldso/ldso/arm/elfinterp.c')
| -rw-r--r-- | ldso/ldso/arm/elfinterp.c | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/ldso/ldso/arm/elfinterp.c b/ldso/ldso/arm/elfinterp.c new file mode 100644 index 000000000..397610bd6 --- /dev/null +++ b/ldso/ldso/arm/elfinterp.c @@ -0,0 +1,374 @@ +/* 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_ARM_NONE", "R_ARM_PC24", "R_ARM_ABS32", "R_ARM_REL32", + "R_ARM_PC13", "R_ARM_ABS16", "R_ARM_ABS12", "R_ARM_THM_ABS5", + "R_ARM_ABS8", "R_ARM_SBREL32", "R_ARM_THM_PC22", "R_ARM_THM_PC8", + "R_ARM_AMP_VCALL9", "R_ARM_SWI24", "R_ARM_THM_SWI8", "R_ARM_XPC25", + "R_ARM_THM_XPC22", "R_ARM_COPY", "R_ARM_GLOB_DAT", "R_ARM_JUMP_SLOT", + "R_ARM_RELATIVE", "R_ARM_GOTOFF", "R_ARM_GOTPC", "R_ARM_GOT32", + "R_ARM_PLT32", "R_ARM_ALU_PCREL_7_0", "R_ARM_ALU_PCREL_15_8", + "R_ARM_ALU_PCREL_23_15", "R_ARM_LDR_SBREL_11_0", "R_ARM_ALU_SBREL_19_12", + "R_ARM_ALU_SBREL_27_20", "R_ARM_GNU_VTENTRY", "R_ARM_GNU_VTINHERIT", + "R_ARM_THM_PC11", "R_ARM_THM_PC9", "R_ARM_RXPC25", "R_ARM_RSBREL32", + "R_ARM_THM_RPC22", "R_ARM_RREL32", "R_ARM_RABS22", "R_ARM_RPC24", + "R_ARM_RBASE", "R_ARM_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 "elf.h" +#include "hash.h" +#include "syscall.h" +#include "string.h" +#include "sysdep.h" + +extern char *_dl_progname; + +extern int _dl_linux_resolve(void); + +unsigned long _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry) +{ + int reloc_type; + Elf32_Rel *this_reloc; + char *strtab; + Elf32_Sym *symtab; + Elf32_Rel *rel_addr; + int symtab_index; + char *new_addr; + char **got_addr; + unsigned long instr_addr; + + rel_addr = (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 = (Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr); + strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr); + + if (reloc_type != R_ARM_JUMP_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 = ((unsigned long) this_reloc->r_offset + + (unsigned long) tpnt->loadaddr); + got_addr = (char **) instr_addr; + +#ifdef DL_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, (unsigned long) 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); + }; +#ifdef DL_DEBUG + if ((unsigned long) 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 long) new_addr; +} + +void _dl_parse_lazy_relocation_information(struct elf_resolve *tpnt, + unsigned long rel_addr, unsigned long rel_size, int type) +{ + int i; + char *strtab; + int reloc_type; + int symtab_index; + Elf32_Sym *symtab; + Elf32_Rel *rpnt; + unsigned long *reloc_addr; + + /* Now parse the relocation information */ + rpnt = (Elf32_Rel *) (rel_addr + tpnt->loadaddr); + rel_size = rel_size / sizeof(Elf32_Rel); + + symtab = + (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 = (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); + + /* 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_ARM_NONE: + break; + case R_ARM_JUMP_SLOT: + *reloc_addr += (unsigned long) 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); + }; + }; +} + +static unsigned long +fix_bad_pc24 (unsigned long *const reloc_addr, unsigned long value) +{ + static void *fix_page; + static unsigned int fix_offset; + unsigned int *fix_address; + if (! fix_page) + { + fix_page = _dl_mmap (NULL, 4096 , PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + fix_offset = 0; + } + + fix_address = (unsigned int *)(fix_page + fix_offset); + fix_address[0] = 0xe51ff004; /* ldr pc, [pc, #-4] */ + fix_address[1] = value; + + fix_offset += 8; + if (fix_offset >= 4096) + fix_page = NULL; + + return (unsigned long)fix_address; +} + + +int _dl_parse_relocation_information(struct elf_resolve *tpnt, + unsigned long rel_addr, unsigned long rel_size, int type) +{ + int i; + char *strtab; + int reloc_type; + int goof = 0; + Elf32_Sym *symtab; + Elf32_Rel *rpnt; + unsigned long *reloc_addr; + unsigned long symbol_addr; + int symtab_index; + + /* Now parse the relocation information */ + + rpnt = (Elf32_Rel *) (rel_addr + tpnt->loadaddr); + rel_size = rel_size / sizeof(Elf32_Rel); + + symtab = (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 = (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; + + if (symtab_index) { + + if (tpnt->libtype == program_interpreter && + _dl_symbol(strtab + symtab[symtab_index].st_name)) + continue; + + symbol_addr = (unsigned long) _dl_find_hash(strtab + symtab[symtab_index].st_name, + tpnt->symbol_scope, (unsigned long) reloc_addr, + (reloc_type == R_ARM_JUMP_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_ARM_NONE: + break; + case R_ARM_ABS32: + *reloc_addr += symbol_addr; + break; + case R_ARM_PC24: + { + unsigned long addend; + long newvalue, topbits; + + addend = *reloc_addr & 0x00ffffff; + if (addend & 0x00800000) addend |= 0xff000000; + + newvalue = symbol_addr - (unsigned long)reloc_addr + (addend << 2); + topbits = newvalue & 0xfe000000; + if (topbits != 0xfe000000 && topbits != 0x00000000) + { + newvalue = fix_bad_pc24(reloc_addr, symbol_addr) + - (unsigned long)reloc_addr + (addend << 2); + topbits = newvalue & 0xfe000000; + if (topbits != 0xfe000000 && topbits != 0x00000000) + { + _dl_fdprintf(2, "R_ARM_PC24 relocation out of range "); + _dl_exit(1); + } + } + newvalue >>= 2; + symbol_addr = (*reloc_addr & 0xff000000) | (newvalue & 0x00ffffff); + *reloc_addr = symbol_addr; + break; + } + case R_ARM_GLOB_DAT: + case R_ARM_JUMP_SLOT: + *reloc_addr = symbol_addr; + break; + case R_ARM_RELATIVE: + *reloc_addr += (unsigned long) tpnt->loadaddr; + break; + case R_ARM_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, unsigned long rel_addr, + unsigned long rel_size, int type) +{ + int i; + char *strtab; + int reloc_type; + int goof = 0; + Elf32_Sym *symtab; + Elf32_Rel *rpnt; + unsigned long *reloc_addr; + unsigned long symbol_addr; + struct elf_resolve *tpnt; + int symtab_index; + + /* Now parse the relocation information */ + + tpnt = xpnt->dyn; + + rpnt = (Elf32_Rel *) (rel_addr + tpnt->loadaddr); + rel_size = rel_size / sizeof(Elf32_Rel); + + symtab = (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 = (unsigned long *) (tpnt->loadaddr + (unsigned long) rpnt->r_offset); + reloc_type = ELF32_R_TYPE(rpnt->r_info); + if (reloc_type != R_ARM_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 long) _dl_find_hash(strtab + + symtab[symtab_index].st_name, xpnt->next, + (unsigned long) 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; +} |