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- /*
- * Meta ELF shared library loader support.
- *
- * 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.
- *
- * Copyright (C) 2013, Imagination Technologies Ltd.
- *
- * Licensed under LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
- */
- #include "ldso.h"
- /* Defined in resolve.S. */
- extern int _dl_linux_resolve(void);
- static inline unsigned long __get_unaligned_reloc(unsigned long *addr)
- {
- char *rel_addr = (char *)addr;
- unsigned long val;
- val = *rel_addr++ & 0xff;
- val |= (*rel_addr++ << 8) & 0x0000ff00;
- val |= (*rel_addr++ << 16) & 0x00ff0000;
- val |= (*rel_addr++ << 24) & 0xff000000;
- return val;
- }
- static inline void __put_unaligned_reloc(unsigned long *addr,
- unsigned long val)
- {
- char *rel_addr = (char *)addr;
- *rel_addr++ = (val & 0x000000ff);
- *rel_addr++ = ((val & 0x0000ff00) >> 8);
- *rel_addr++ = ((val & 0x00ff0000) >> 16);
- *rel_addr++ = ((val & 0xff000000) >> 24);
- }
- unsigned long
- _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)
- {
- int symtab_index;
- char *strtab;
- char *symname;
- char *new_addr;
- char *rel_addr;
- char **got_addr;
- ElfW(Sym) *symtab;
- ELF_RELOC *this_reloc;
- unsigned long instr_addr;
- rel_addr = (char *)tpnt->dynamic_info[DT_JMPREL];
- this_reloc = (ELF_RELOC *)(intptr_t)(rel_addr + reloc_entry);
- symtab_index = ELF_R_SYM(this_reloc->r_info);
- symtab = (ElfW(Sym) *)(intptr_t)tpnt->dynamic_info[DT_SYMTAB];
- strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
- symname = strtab + symtab[symtab_index].st_name;
- /* Address of the 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, &_dl_loaded_modules->symbol_scope, tpnt,
- ELF_RTYPE_CLASS_PLT, NULL);
- 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 (_dl_debug_bindings) {
- _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);
- if (_dl_debug_detail)
- _dl_dprintf(_dl_debug_file,
- "\n\tpatched: %x ==> %x @ %x\n",
- *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 r_scope_elem *scope,
- unsigned long rel_addr, unsigned long rel_size,
- int (*reloc_fnc)(struct elf_resolve *tpnt, struct r_scope_elem *scope,
- ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab))
- {
- int symtab_index;
- unsigned int i;
- char *strtab;
- ElfW(Sym) *symtab;
- ELF_RELOC *rpnt;
- /* Parse the relocation information. */
- rpnt = (ELF_RELOC *)(intptr_t)rel_addr;
- rel_size /= sizeof(ELF_RELOC);
- symtab = (ElfW(Sym) *)(intptr_t)tpnt->dynamic_info[DT_SYMTAB];
- strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
- for (i = 0; i < rel_size; i++, rpnt++) {
- int res;
- symtab_index = ELF_R_SYM(rpnt->r_info);
- debug_sym(symtab, strtab, symtab_index);
- debug_reloc(symtab, strtab, rpnt);
- /* Pass over to actual relocation function. */
- 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 = ELF_R_TYPE(rpnt->r_info);
- _dl_dprintf(2, "can't handle reloc type %x\n",
- reloc_type);
- _dl_exit(-res);
- } else if (unlikely(res > 0)) {
- _dl_dprintf(2, "can't resolve symbol\n");
- return res;
- }
- }
- return 0;
- }
- static int
- _dl_do_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
- ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
- {
- int reloc_type;
- int symtab_index;
- char *symname = NULL;
- unsigned long *reloc_addr;
- unsigned long symbol_addr;
- #if defined (__SUPPORT_LD_DEBUG__)
- unsigned long old_val = 0;
- #endif
- struct elf_resolve *tls_tpnt = NULL;
- struct symbol_ref sym_ref;
- reloc_addr = (unsigned long *)(tpnt->loadaddr + rpnt->r_offset);
- reloc_type = ELF_R_TYPE(rpnt->r_info);
- symtab_index = ELF_R_SYM(rpnt->r_info);
- symbol_addr = 0;
- sym_ref.sym = &symtab[symtab_index];
- sym_ref.tpnt = NULL;
- if (symtab_index) {
- symname = strtab + symtab[symtab_index].st_name;
- symbol_addr = (unsigned long)_dl_find_hash(symname, scope, tpnt,
- elf_machine_type_class(reloc_type), &sym_ref);
- if (!symbol_addr
- && ELF_ST_TYPE(symtab[symtab_index].st_info) != STT_TLS
- && ELF_ST_BIND(symtab[symtab_index].st_info) != STB_WEAK) {
- _dl_dprintf(2, "%s: can't resolve symbol '%s'\n",
- _dl_progname, symname);
- return 1;
- };
- if (_dl_trace_prelink) {
- _dl_debug_lookup(symname, tpnt, &symtab[symtab_index],
- &sym_ref, elf_machine_type_class(reloc_type));
- }
- tls_tpnt = sym_ref.tpnt;
- }
- #if defined (__SUPPORT_LD_DEBUG__)
- if (reloc_type != R_METAG_NONE)
- old_val = __get_unaligned_reloc(reloc_addr);
- #endif
- #if defined USE_TLS && USE_TLS
- /* In case of a TLS reloc, tls_tpnt NULL means we have an 'anonymous'
- symbol. This is the case for a static tls variable, so the lookup
- module is just that one is referencing the tls variable. */
- if (!tls_tpnt)
- tls_tpnt = tpnt;
- #endif
- switch (reloc_type) {
- case R_METAG_NONE:
- break;
- case R_METAG_GLOB_DAT:
- case R_METAG_JMP_SLOT:
- case R_METAG_ADDR32:
- __put_unaligned_reloc(reloc_addr,
- symbol_addr + rpnt->r_addend);
- break;
- case R_METAG_COPY:
- #if defined (__SUPPORT_LD_DEBUG__)
- if (_dl_debug_move)
- _dl_dprintf(_dl_debug_file,
- "\t%s move %d bytes from %x to %x\n",
- symname, symtab[symtab_index].st_size,
- symbol_addr + rpnt->r_addend,
- reloc_addr);
- #endif
- _dl_memcpy((char *)reloc_addr,
- (char *)symbol_addr + rpnt->r_addend,
- symtab[symtab_index].st_size);
- break;
- case R_METAG_RELATIVE:
- __put_unaligned_reloc(reloc_addr,
- (unsigned long)tpnt->loadaddr +
- rpnt->r_addend);
- break;
- #if defined USE_TLS && USE_TLS
- case R_METAG_TLS_DTPMOD:
- *reloc_addr = tls_tpnt->l_tls_modid;
- break;
- case R_METAG_TLS_DTPOFF:
- *reloc_addr = symbol_addr;
- break;
- case R_METAG_TLS_TPOFF:
- CHECK_STATIC_TLS ((struct link_map *) tls_tpnt);
- *reloc_addr = tls_tpnt->l_tls_offset + symbol_addr + rpnt->r_addend;
- break;
- #endif
- default:
- return -1; /* Calls _dl_exit(1). */
- }
- #if defined (__SUPPORT_LD_DEBUG__)
- if (_dl_debug_reloc && _dl_debug_detail && reloc_type != R_METAG_NONE) {
- unsigned long new_val = __get_unaligned_reloc(reloc_addr);
- _dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x\n",
- old_val, new_val, reloc_addr);
- }
- #endif
- return 0;
- }
- static int
- _dl_do_lazy_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
- ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
- {
- int reloc_type;
- unsigned long *reloc_addr;
- #if defined (__SUPPORT_LD_DEBUG__)
- unsigned long old_val;
- #endif
- reloc_addr = (unsigned long *)(tpnt->loadaddr + rpnt->r_offset);
- reloc_type = ELF_R_TYPE(rpnt->r_info);
- #if defined (__SUPPORT_LD_DEBUG__)
- old_val = *reloc_addr;
- #endif
- switch (reloc_type) {
- case R_METAG_NONE:
- break;
- case R_METAG_JMP_SLOT:
- *reloc_addr += (unsigned long)tpnt->loadaddr;
- break;
- default:
- return -1; /* Calls _dl_exit(1). */
- }
- #if defined (__SUPPORT_LD_DEBUG__)
- if (_dl_debug_reloc && _dl_debug_detail)
- _dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x\n",
- old_val, *reloc_addr, reloc_addr);
- #endif
- return 0;
- }
- /* External interface to the generic part of the dynamic linker. */
- void
- _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
- unsigned long rel_addr,
- unsigned long rel_size)
- {
- _dl_parse(rpnt->dyn, NULL, rel_addr, rel_size, _dl_do_lazy_reloc);
- }
- int
- _dl_parse_relocation_information(struct dyn_elf *rpnt,
- struct r_scope_elem *scope,
- unsigned long rel_addr,
- unsigned long rel_size)
- {
- return _dl_parse(rpnt->dyn, scope, rel_addr,
- rel_size, _dl_do_reloc);
- }
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