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- /* vi: set sw=4 ts=4: */
- /* ARM ELF shared library loader suppport
- *
- * Copyright (C) 2001-2004 Erik Andersen
- *
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. The name of the above contributors may not be
- * used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
- #if defined (__SUPPORT_LD_DEBUG__)
- static const char *_dl_reltypes_tab[] =
- {
- [0] "R_ARM_NONE", "R_ARM_PC24", "R_ARM_ABS32", "R_ARM_REL32",
- [4] "R_ARM_PC13", "R_ARM_ABS16", "R_ARM_ABS12", "R_ARM_THM_ABS5",
- [8] "R_ARM_ABS8", "R_ARM_SBREL32","R_ARM_THM_PC22", "R_ARM_THM_PC8",
- [12] "R_ARM_AMP_VCALL9", "R_ARM_SWI24", "R_ARM_THM_SWI8", "R_ARM_XPC25",
- [16] "R_ARM_THM_XPC22",
- [20] "R_ARM_COPY", "R_ARM_GLOB_DAT","R_ARM_JUMP_SLOT", "R_ARM_RELATIVE",
- [24] "R_ARM_GOTOFF", "R_ARM_GOTPC", "R_ARM_GOT32", "R_ARM_PLT32",
- [32] "R_ARM_ALU_PCREL_7_0","R_ARM_ALU_PCREL_15_8","R_ARM_ALU_PCREL_23_15","R_ARM_LDR_SBREL_11_0",
- [36] "R_ARM_ALU_SBREL_19_12","R_ARM_ALU_SBREL_27_20",
- [100] "R_ARM_GNU_VTENTRY","R_ARM_GNU_VTINHERIT","R_ARM_THM_PC11","R_ARM_THM_PC9",
- [249] "R_ARM_RXPC25", "R_ARM_RSBREL32", "R_ARM_THM_RPC22", "R_ARM_RREL32",
- [253] "R_ARM_RABS22", "R_ARM_RPC24", "R_ARM_RBASE",
- };
- static const char *
- _dl_reltypes(int type)
- {
- static char buf[22];
- const char *str;
- if (type >= (sizeof (_dl_reltypes_tab)/sizeof(_dl_reltypes_tab[0])) ||
- NULL == (str = _dl_reltypes_tab[type]))
- {
- str =_dl_simple_ltoa( buf, (unsigned long)(type));
- }
- return str;
- }
- static
- void debug_sym(Elf32_Sym *symtab,char *strtab,int symtab_index)
- {
- if(_dl_debug_symbols)
- {
- if(symtab_index){
- _dl_dprintf(_dl_debug_file, "\n%s\tvalue=%x\tsize=%x\tinfo=%x\tother=%x\tshndx=%x",
- strtab + symtab[symtab_index].st_name,
- symtab[symtab_index].st_value,
- symtab[symtab_index].st_size,
- symtab[symtab_index].st_info,
- symtab[symtab_index].st_other,
- symtab[symtab_index].st_shndx);
- }
- }
- }
- static void debug_reloc(Elf32_Sym *symtab,char *strtab, ELF_RELOC *rpnt)
- {
- if(_dl_debug_reloc)
- {
- int symtab_index;
- const char *sym;
- symtab_index = ELF32_R_SYM(rpnt->r_info);
- sym = symtab_index ? strtab + symtab[symtab_index].st_name : "sym=0x0";
- #ifdef ELF_USES_RELOCA
- _dl_dprintf(_dl_debug_file, "\n%s\toffset=%x\taddend=%x %s",
- _dl_reltypes(ELF32_R_TYPE(rpnt->r_info)),
- rpnt->r_offset,
- rpnt->r_addend,
- sym);
- #else
- _dl_dprintf(_dl_debug_file, "\n%s\toffset=%x %s",
- _dl_reltypes(ELF32_R_TYPE(rpnt->r_info)),
- rpnt->r_offset,
- sym);
- #endif
- }
- }
- #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. */
- extern int _dl_linux_resolve(void);
- unsigned long _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)
- {
- int reloc_type;
- ELF_RELOC *this_reloc;
- char *strtab;
- char *symname;
- Elf32_Sym *symtab;
- ELF_RELOC *rel_addr;
- int symtab_index;
- char *new_addr;
- char **got_addr;
- unsigned long instr_addr;
- rel_addr = (ELF_RELOC *) tpnt->dynamic_info[DT_JMPREL];
- 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];
- strtab = (char *) tpnt->dynamic_info[DT_STRTAB];
- symname = strtab + symtab[symtab_index].st_name;
- if (unlikely(reloc_type != R_ARM_JUMP_SLOT)) {
- _dl_dprintf(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;
- /* Get the address of the GOT entry */
- new_addr = _dl_find_hash(symname, tpnt->symbol_scope,
- tpnt, ELF_RTYPE_CLASS_PLT);
- if (unlikely(!new_addr)) {
- _dl_dprintf(2, "%s: can't resolve symbol '%s'\n",
- _dl_progname, symname);
- _dl_exit(1);
- };
- #if defined (__SUPPORT_LD_DEBUG__)
- if ((unsigned long) got_addr < 0x40000000)
- {
- if (_dl_debug_bindings)
- {
- _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);
- if(_dl_debug_detail) _dl_dprintf(_dl_debug_file,
- "\tpatch %x ==> %x @ %x", *got_addr, new_addr, got_addr);
- }
- }
- if (!_dl_debug_nofixups) {
- *got_addr = new_addr;
- }
- #else
- *got_addr = new_addr;
- #endif
- return (unsigned long) new_addr;
- }
- static int
- _dl_parse(struct elf_resolve *tpnt, struct dyn_elf *scope,
- unsigned long rel_addr, unsigned long rel_size,
- int (*reloc_fnc) (struct elf_resolve *tpnt, struct dyn_elf *scope,
- ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab))
- {
- int i;
- char *strtab;
- int goof = 0;
- Elf32_Sym *symtab;
- ELF_RELOC *rpnt;
- int symtab_index;
- /* Now parse the relocation information */
- rpnt = (ELF_RELOC *) rel_addr;
- rel_size = rel_size / sizeof(ELF_RELOC);
- symtab = (Elf32_Sym *) tpnt->dynamic_info[DT_SYMTAB];
- strtab = (char *) tpnt->dynamic_info[DT_STRTAB];
- for (i = 0; i < rel_size; i++, rpnt++) {
- int res;
- symtab_index = ELF32_R_SYM(rpnt->r_info);
- #if defined (__SUPPORT_LD_DEBUG__)
- debug_sym(symtab,strtab,symtab_index);
- debug_reloc(symtab,strtab,rpnt);
- #endif
- res = reloc_fnc (tpnt, scope, rpnt, symtab, strtab);
- if (res==0) continue;
- _dl_dprintf(2, "\n%s: ",_dl_progname);
- if (symtab_index)
- _dl_dprintf(2, "symbol '%s': ", strtab + symtab[symtab_index].st_name);
- if (unlikely(res <0))
- {
- int reloc_type = ELF32_R_TYPE(rpnt->r_info);
- #if defined (__SUPPORT_LD_DEBUG__)
- _dl_dprintf(2, "can't handle reloc type %s\n ", _dl_reltypes(reloc_type));
- #else
- _dl_dprintf(2, "can't handle reloc type %x\n", reloc_type);
- #endif
- _dl_exit(-res);
- }
- if (unlikely(res >0))
- {
- _dl_dprintf(2, "can't resolve symbol\n");
- goof += res;
- }
- }
- return goof;
- }
- #if 0
- 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, PAGE_SIZE , 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 >= PAGE_SIZE)
- fix_page = NULL;
- return (unsigned long)fix_address;
- }
- #endif
- static int
- _dl_do_reloc (struct elf_resolve *tpnt,struct dyn_elf *scope,
- ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab)
- {
- int reloc_type;
- int symtab_index;
- unsigned long *reloc_addr;
- unsigned long symbol_addr;
- int goof = 0;
- 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) {
- symbol_addr = (unsigned long) _dl_find_hash(strtab + symtab[symtab_index].st_name,
- scope, tpnt, elf_machine_type_class(reloc_type));
- /*
- * 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_WEAK) {
- _dl_dprintf (2, "%s: can't resolve symbol '%s'\n",
- _dl_progname, strtab + symtab[symtab_index].st_name);
- _dl_exit (1);
- }
- }
- #if defined (__SUPPORT_LD_DEBUG__)
- {
- unsigned long old_val = *reloc_addr;
- #endif
- switch (reloc_type) {
- case R_ARM_NONE:
- break;
- case R_ARM_ABS32:
- *reloc_addr += symbol_addr;
- break;
- case R_ARM_PC24:
- #if 0
- {
- 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 (unlikely(topbits != 0xfe000000 && topbits != 0x00000000))
- {
- _dl_dprintf(2,"symbol '%s': R_ARM_PC24 relocation out of range.",
- symtab[symtab_index].st_name);
- _dl_exit(1);
- }
- }
- newvalue >>= 2;
- symbol_addr = (*reloc_addr & 0xff000000) | (newvalue & 0x00ffffff);
- *reloc_addr = symbol_addr;
- break;
- }
- #else
- _dl_dprintf(2,"R_ARM_PC24: Compile shared libraries with -fPIC!\n");
- _dl_exit(1);
- #endif
- 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:
- _dl_memcpy((void *) reloc_addr,
- (void *) symbol_addr, symtab[symtab_index].st_size);
- break;
- default:
- return -1; /*call _dl_exit(1) */
- }
- #if defined (__SUPPORT_LD_DEBUG__)
- if(_dl_debug_reloc && _dl_debug_detail)
- _dl_dprintf(_dl_debug_file, "\tpatch: %x ==> %x @ %x", old_val, *reloc_addr, reloc_addr);
- }
- #endif
- return goof;
- }
- static int
- _dl_do_lazy_reloc (struct elf_resolve *tpnt, struct dyn_elf *scope,
- ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab)
- {
- int reloc_type;
- unsigned long *reloc_addr;
- reloc_addr = (unsigned long *) (tpnt->loadaddr + (unsigned long) rpnt->r_offset);
- reloc_type = ELF32_R_TYPE(rpnt->r_info);
- #if defined (__SUPPORT_LD_DEBUG__)
- {
- unsigned long old_val = *reloc_addr;
- #endif
- switch (reloc_type) {
- case R_ARM_NONE:
- break;
- case R_ARM_JUMP_SLOT:
- *reloc_addr += (unsigned long) tpnt->loadaddr;
- break;
- default:
- return -1; /*call _dl_exit(1) */
- }
- #if defined (__SUPPORT_LD_DEBUG__)
- if(_dl_debug_reloc && _dl_debug_detail)
- _dl_dprintf(_dl_debug_file, "\tpatch: %x ==> %x @ %x", old_val, *reloc_addr, reloc_addr);
- }
- #endif
- return 0;
- }
- void _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
- unsigned long rel_addr, unsigned long rel_size)
- {
- (void)_dl_parse(rpnt->dyn, NULL, rel_addr, rel_size, _dl_do_lazy_reloc);
- }
- int _dl_parse_relocation_information(struct dyn_elf *rpnt,
- unsigned long rel_addr, unsigned long rel_size)
- {
- return _dl_parse(rpnt->dyn, rpnt->dyn->symbol_scope, rel_addr, rel_size, _dl_do_reloc);
- }
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