/* $NetBSD: reloc.c,v 1.9 1999/02/22 17:06:11 pk Exp $ */ /* * Copyright 1996 John D. Polstra. * Copyright 1996 Matt Thomas * 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. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by John Polstra. * 4. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. */ /* * Dynamic linker for ELF. * * John Polstra . */ #include #include #include #include #include #include #include #include #include #include #include #include "debug.h" #include "rtld.h" #if defined(__alpha__) || defined(__powerpc__) || defined(__i386__) /* * XXX: These don't work for the alpha and i386; don't know about powerpc * The alpha and the i386 avoid the problem by compiling everything PIC. * These relocation are supposed to be writing the address of the * function to be called on the bss.rel or bss.rela segment, but: * - st_size == 0 * - on the i386 at least the call instruction is a direct call * not an indirect call. */ static int _rtld_do_copy_relocation( const Obj_Entry *dstobj, const Elf_RelA *rela) { void *dstaddr = (void *) (dstobj->relocbase + rela->r_offset); const Elf_Sym *dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info); const char *name = dstobj->strtab + dstsym->st_name; unsigned long hash = _rtld_elf_hash(name); size_t size = dstsym->st_size; const void *srcaddr; const Elf_Sym *srcsym; Obj_Entry *srcobj; for (srcobj = dstobj->next; srcobj != NULL; srcobj = srcobj->next) if ((srcsym = _rtld_symlook_obj(name, hash, srcobj, false)) != NULL) break; if (srcobj == NULL) { _rtld_error("Undefined symbol \"%s\" referenced from COPY" " relocation in %s", name, dstobj->path); return -1; } srcaddr = (const void *) (srcobj->relocbase + srcsym->st_value); memcpy(dstaddr, srcaddr, size); #ifdef RTLD_DEBUG_RELOC dbg("COPY %s %s %s --> src=%p dst=%p *dst= %p size %d", dstobj->path, srcobj->path, name, (void *)srcaddr, (void *)dstaddr, (void *)*(long *)dstaddr, size); #endif return 0; } #endif /* __alpha__ || __powerpc__ || __i386__ */ /* * Process the special R_xxx_COPY relocations in the main program. These * copy data from a shared object into a region in the main program's BSS * segment. * * Returns 0 on success, -1 on failure. */ int _rtld_do_copy_relocations( const Obj_Entry *dstobj) { assert(dstobj->mainprog); /* COPY relocations are invalid elsewhere */ #if defined(__alpha__) || defined(__powerpc__) || defined(__i386__) if (dstobj->rel != NULL) { const Elf_Rel *rel; for (rel = dstobj->rel; rel < dstobj->rellim; ++rel) { if (ELF_R_TYPE(rel->r_info) == R_TYPE(COPY)) { Elf_RelA ourrela; ourrela.r_info = rel->r_info; ourrela.r_offset = rel->r_offset; ourrela.r_addend = 0; if (_rtld_do_copy_relocation(dstobj, &ourrela) < 0) return -1; } } } if (dstobj->rela != NULL) { const Elf_RelA *rela; for (rela = dstobj->rela; rela < dstobj->relalim; ++rela) { if (ELF_R_TYPE(rela->r_info) == R_TYPE(COPY)) { if (_rtld_do_copy_relocation(dstobj, rela) < 0) return -1; } } } #endif /* __alpha__ || __powerpc__ || __i386__ */ return 0; } #ifdef __sparc__ /* * The following table holds for each relocation type: * - the width in bits of the memory location the relocation * applies to (not currently used) * - the number of bits the relocation value must be shifted to the * right (i.e. discard least significant bits) to fit into * the appropriate field in the instruction word. * - flags indicating whether * * the relocation involves a symbol * * the relocation is relative to the current position * * the relocation is for a GOT entry * * the relocation is relative to the load address * */ #define _RF_S 0x80000000 /* Resolve symbol */ #define _RF_A 0x40000000 /* Use addend */ #define _RF_P 0x20000000 /* Location relative */ #define _RF_G 0x10000000 /* GOT offset */ #define _RF_B 0x08000000 /* Load address relative */ #define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */ #define _RF_RS(s) ( (s) & 0xff) /* right shift */ static int reloc_target_flags[] = { 0, /* NONE */ _RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */ _RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */ _RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */ _RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */ _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */ _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */ _RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */ _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */ _RF_SZ(32) | _RF_RS(0), /* COPY */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_DAT */ _RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */ _RF_A| _RF_SZ(32) | _RF_RS(0), /* RELATIVE */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* UA_32 */ /*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PLT32 */ /*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HIPLT22 */ /*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */ /*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */ /*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PCPLT22 */ /*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PCPLT32 */ _RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 10 */ _RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 11 */ _RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 64 */ _RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* OLO10 */ _RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HH22 */ _RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HM10 */ _RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LM22 */ _RF_S|_RF_A|_RF_P|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* WDISP16 */ _RF_S|_RF_A|_RF_P|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* WDISP19 */ /*unknown*/ _RF_SZ(32) | _RF_RS(0), /* GLOB_JMP */ /*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 7 */ /*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 5 */ /*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 6 */ }; #define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0) #define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0) #define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff) #define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff) static int reloc_target_bitmask[] = { #define _BM(x) (~(-(1ULL << (x)))) 0, /* NONE */ _BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */ _BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */ _BM(30), _BM(22), /* WDISP30, WDISP22 */ _BM(22), _BM(22), /* HI22, _22 */ _BM(13), _BM(10), /* RELOC_13, _LO10 */ _BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */ _BM(10), _BM(22), /* _PC10, _PC22 */ _BM(30), 0, /* _WPLT30, _COPY */ -1, -1, _BM(22), /* _GLOB_DAT, JMP_SLOT, _RELATIVE */ _BM(32), _BM(32), /* _UA32, PLT32 */ _BM(22), _BM(10), /* _HIPLT22, LOPLT10 */ _BM(32), _BM(22), _BM(10), /* _PCPLT32, _PCPLT22, _PCPLT10 */ _BM(10), _BM(11), -1, /* _10, _11, _64 */ _BM(10), _BM(22), /* _OLO10, _HH22 */ _BM(10), _BM(22), /* _HM10, _LM22 */ _BM(16), _BM(19), /* _WDISP16, _WDISP19 */ -1, /* GLOB_JMP */ _BM(7), _BM(5), _BM(6) /* _7, _5, _6 */ #undef _BM }; #define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t]) static int _rtld_relocate_nonplt_object( const Obj_Entry *obj, const Elf_RelA *rela) { Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset); Elf_Word type, value, mask; type = ELF_R_TYPE(rela->r_info); if (type == R_TYPE(NONE)) return (0); /* * We use the fact that relocation types are an `enum' * Note: R_SPARC_6 is currently numerically largest. */ if (type > R_TYPE(6)) return (-1); value = rela->r_addend; if (RELOC_RESOLVE_SYMBOL(type)) { const Elf_Sym *def; const Obj_Entry *defobj; /* Find the symbol */ def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false); if (def == NULL) return (-1); /* Add in the symbol's absolute address */ value += (Elf_Word)(defobj->relocbase + def->st_value); } if (RELOC_PC_RELATIVE(type)) { value -= (Elf_Word)where; } mask = RELOC_VALUE_BITMASK(type); value >>= RELOC_VALUE_RIGHTSHIFT(type); value &= mask; /* We ignore alignment restrictions here */ *where &= ~mask; *where |= value; return (0); } static int __rtld_relocate_plt_object( const Obj_Entry *obj, const Elf_RelA *rela, bool bind_now, caddr_t *addrp) { const Elf_Sym *def; const Obj_Entry *defobj; Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset); Elf_Addr value; if (bind_now == 0 && obj->pltgot != NULL) return (0); /* Fully resolve procedure addresses now */ assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)); def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, true); if (def == NULL) return (-1); value = (Elf_Addr) (defobj->relocbase + def->st_value); #ifdef RTLD_DEBUG_RELOC dbg("bind now %d/fixup in %s --> old=%p new=%p", (int)bind_now, defobj->strtab + def->st_name, (void *)*where, (void *)value); #endif /* * At the PLT entry pointed at by `where', we now construct * a direct transfer to the now fully resolved function * address. The resulting code in the jump slot is: * * sethi %hi(addr), %g1 * jmp %g1+%lo(addr) * nop ! delay slot */ #define SETHI 0x03000000 #define JMP 0x81c06000 #define NOP 0x01000000 where[0] = SETHI | ((value >> 10) & 0x003fffff); where[1] = JMP | (value & 0x000003ff); where[2] = NOP; if (addrp != NULL) *addrp = (caddr_t)value; return (0); } #define _rtld_relocate_plt_object(obj, rela, bind_now) \ __rtld_relocate_plt_object(obj, rela, bind_now, NULL) caddr_t _rtld_bind( const Obj_Entry *obj, Elf_Word reloff) { const Elf_RelA *rela; Elf_RelA ourrela; caddr_t addr; if (obj->pltrel != NULL) { const Elf_Rel *rel; rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); ourrela.r_info = rel->r_info; ourrela.r_offset = rel->r_offset; rela = &ourrela; } else { rela = (const Elf_RelA *) ((caddr_t) obj->pltrela + reloff); } if (__rtld_relocate_plt_object(obj, rela, true, &addr) < 0) _rtld_die(); return (addr); return *(caddr_t *)(obj->relocbase + rela->r_offset); } #else /* __sparc__ */ static int _rtld_relocate_nonplt_object( const Obj_Entry *obj, const Elf_RelA *rela) { Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset); switch (ELF_R_TYPE(rela->r_info)) { case R_TYPE(NONE): break; #ifdef __i386__ case R_TYPE(GOT32): { const Elf_Sym *def; const Obj_Entry *defobj; def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false); if (def == NULL) return -1; if (*where != (Elf_Addr) (defobj->relocbase + def->st_value)) *where = (Elf_Addr) (defobj->relocbase + def->st_value); #ifdef RTLD_DEBUG_RELOC dbg("GOT32 %s in %s --> %p in %s", defobj->strtab + def->st_name, obj->path, (void *)*where, defobj->path); #endif break; } case R_TYPE(PC32): /* * I don't think the dynamic linker should ever see this * type of relocation. But the binutils-2.6 tools sometimes * generate it. */ { const Elf_Sym *def; const Obj_Entry *defobj; def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false); if (def == NULL) return -1; *where += (Elf_Addr) (defobj->relocbase + def->st_value) - (Elf_Addr) where; #ifdef RTLD_DEBUG_RELOC dbg("PC32 %s in %s --> %p in %s", defobj->strtab + def->st_name, obj->path, (void *)*where, defobj->path); #endif break; } case R_TYPE(32): { const Elf_Sym *def; const Obj_Entry *defobj; def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false); if (def == NULL) return -1; *where += (Elf_Addr)(defobj->relocbase + def->st_value); #ifdef RTLD_DEBUG_RELOC dbg("32 %s in %s --> %p in %s", defobj->strtab + def->st_name, obj->path, (void *)*where, defobj->path); #endif break; } #endif /* __i386__ */ #ifdef __alpha__ case R_ALPHA_REFQUAD: { const Elf_Sym *def; const Obj_Entry *defobj; Elf_Addr tmp_value; def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false); if (def == NULL) return -1; tmp_value = (Elf_Addr) (defobj->relocbase + def->st_value) + *where + rela->r_addend; if (*where != tmp_value) *where = tmp_value; #ifdef RTLD_DEBUG_RELOC dbg("REFQUAD %s in %s --> %p in %s", defobj->strtab + def->st_name, obj->path, (void *)*where, defobj->path); #endif break; } #endif /* __alpha__ */ #if defined(__i386__) || defined(__alpha__) case R_TYPE(GLOB_DAT): { const Elf_Sym *def; const Obj_Entry *defobj; def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false); if (def == NULL) return -1; if (*where != (Elf_Addr) (defobj->relocbase + def->st_value)) *where = (Elf_Addr) (defobj->relocbase + def->st_value); #ifdef RTLD_DEBUG_RELOC dbg("GLOB_DAT %s in %s --> %p in %s", defobj->strtab + def->st_name, obj->path, (void *)*where, defobj->path); #endif break; } case R_TYPE(RELATIVE): { extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; extern Elf_Dyn _DYNAMIC; if (obj != &_rtld_objself || (caddr_t)where < (caddr_t)_GLOBAL_OFFSET_TABLE_ || (caddr_t)where >= (caddr_t)&_DYNAMIC) { *where += (Elf_Addr) obj->relocbase; #ifdef RTLD_DEBUG_RELOC dbg("RELATIVE in %s --> %p", obj->path, (void *)*where); #endif } #ifdef RTLD_DEBUG_RELOC else dbg("RELATIVE in %s stays at %p", obj->path, (void *)*where); #endif break; } case R_TYPE(COPY): { /* * These are deferred until all other relocations have * been done. All we do here is make sure that the COPY * relocation is not in a shared library. They are allowed * only in executable files. */ if (!obj->mainprog) { _rtld_error("%s: Unexpected R_COPY relocation in shared library", obj->path); return -1; } #ifdef RTLD_DEBUG_RELOC dbg("COPY (avoid in main)"); #endif break; } #endif /* __i386__ || __alpha__ */ #ifdef __mips__ case R_TYPE(REL32): { /* 32-bit PC-relative reference */ const Elf_Sym *def; const Obj_Entry *defobj; def = obj->symtab + ELF_R_SYM(rela->r_info); if (ELF_SYM_BIND(def->st_info) == Elf_estb_local && (ELF_SYM_TYPE(def->st_info) == Elf_estt_section || ELF_SYM_TYPE(def->st_info) == Elf_estt_notype)) { *where += (Elf_Addr) obj->relocbase; #ifdef RTLD_DEBUG_RELOC dbg("REL32 in %s --> %p", obj->path, (void *)*where); #endif } else { /* XXX maybe do something re: bootstrapping? */ def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false); if (def == NULL) return -1; *where += (Elf_Addr)(defobj->relocbase + def->st_value); #ifdef RTLD_DEBUG_RELOC dbg("REL32 %s in %s --> %p in %s", defobj->strtab + def->st_name, obj->path, (void *)*where, defobj->path); #endif } break; } #endif /* mips */ #ifdef __powerpc__ case R_TYPE(32): /* word32 S + A */ case R_TYPE(GLOB_DAT): { /* word32 S + A */ const Elf_Sym *def; const Obj_Entry *defobj; Elf_Addr x; def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, false); if (def == NULL) return -1; x = (Elf_Addr)(defobj->relocbase + def->st_value + rela->r_addend); if (*where != x) *where = x; #ifdef RTLD_DEBUG_RELOC dbg("32/GLOB_DAT %s in %s --> %p in %s", defobj->strtab + def->st_name, obj->path, (void *)*where, defobj->path); #endif break; } case R_TYPE(COPY): #ifdef RTLD_DEBUG_RELOC dbg("COPY"); #endif break; case R_TYPE(JMP_SLOT): #ifdef RTLD_DEBUG_RELOC dbg("JMP_SLOT"); #endif break; case R_TYPE(RELATIVE): { /* word32 B + A */ if (obj == &_rtld_objself && *where == (Elf_Addr)obj->relocbase + rela->r_addend) break; /* GOT - already done */ *where = (Elf_Addr)obj->relocbase + rela->r_addend; #ifdef RTLD_DEBUG_RELOC dbg("RELATIVE in %s --> %p", obj->path, (void *)*where); #endif break; } #endif /* __powerpc__ */ default: { const Elf_Sym *def; const Obj_Entry *defobj; def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, true); dbg("sym = %lu, type = %lu, offset = %p, addend = %p, contents = %p, symbol = %s", (u_long)ELF_R_SYM(rela->r_info), (u_long)ELF_R_TYPE(rela->r_info), (void *)rela->r_offset, (void *)rela->r_addend, (void *)*where, def ? defobj->strtab + def->st_name : "??"); _rtld_error("%s: Unsupported relocation type %d in non-PLT relocations\n", obj->path, ELF_R_TYPE(rela->r_info)); return -1; } } return 0; } static int _rtld_relocate_plt_object( const Obj_Entry *obj, const Elf_RelA *rela, bool bind_now) { Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset); Elf_Addr new_value; /* Fully resolve procedure addresses now */ #if defined(__powerpc__) return _rtld_reloc_powerpc_plt(obj, rela, bind_now); #endif #if defined(__alpha__) || defined(__i386__) /* (jrs) */ if (bind_now || obj->pltgot == NULL) { const Elf_Sym *def; const Obj_Entry *defobj; assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)); def = _rtld_find_symdef(_rtld_objlist, rela->r_info, NULL, obj, &defobj, true); if (def == NULL) return -1; new_value = (Elf_Addr) (defobj->relocbase + def->st_value); #ifdef RTLD_DEBUG_RELOC dbg("bind now %d/fixup in %s --> old=%p new=%p", (int)bind_now, defobj->strtab + def->st_name, (void *)*where, (void *)new_value); #endif } else #endif /* __alpha__ (jrs) */ if (!obj->mainprog) { /* Just relocate the GOT slots pointing into the PLT */ new_value = *where + (Elf_Addr) (obj->relocbase); #ifdef RTLD_DEBUG_RELOC dbg("fixup !main in %s --> %p", obj->path, (void *)*where); #endif } else { return 0; } /* * Since this page is probably copy-on-write, let's not write * it unless we really really have to. */ if (*where != new_value) *where = new_value; return 0; } caddr_t _rtld_bind( const Obj_Entry *obj, Elf_Word reloff) { const Elf_RelA *rela; Elf_RelA ourrela; if (obj->pltrel != NULL) { ourrela.r_info = ((const Elf_Rel *) ((caddr_t) obj->pltrel + reloff))->r_info; ourrela.r_offset = ((const Elf_Rel *) ((caddr_t) obj->pltrel + reloff))->r_offset; rela = &ourrela; } else { rela = (const Elf_RelA *) ((caddr_t) obj->pltrela + reloff); } if (__rtld_relocate_plt_object(obj, rela, true) < 0) _rtld_die(); return *(caddr_t *)(obj->relocbase + rela->r_offset); } #endif /* __sparc__ */ /* * Relocate newly-loaded shared objects. The argument is a pointer to * the Obj_Entry for the first such object. All objects from the first * to the end of the list of objects are relocated. Returns 0 on success, * or -1 on failure. */ int _rtld_relocate_objects( Obj_Entry *first, bool bind_now) { Obj_Entry *obj; int ok = 1; for (obj = first; obj != NULL; obj = obj->next) { if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || obj->symtab == NULL || obj->strtab == NULL) { _rtld_error("%s: Shared object has no run-time symbol table", obj->path); return -1; } dbg(" relocating %s (%ld/%ld rel/rela, %ld/%ld plt rel/rela)", obj->path, (long)(obj->rellim - obj->rel), (long)(obj->relalim - obj->rela), (long)(obj->pltrellim - obj->pltrel), (long)(obj->pltrelalim - obj->pltrela)); if (obj->textrel) { /* There are relocations to the write-protected text segment. */ if (mprotect(obj->mapbase, obj->textsize, PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { _rtld_error("%s: Cannot write-enable text segment: %s", obj->path, xstrerror(errno)); return -1; } } if (obj->rel != NULL) { /* Process the non-PLT relocations. */ const Elf_Rel *rel; for (rel = obj->rel; rel < obj->rellim; ++rel) { Elf_RelA ourrela; ourrela.r_info = rel->r_info; ourrela.r_offset = rel->r_offset; #if defined(__mips__) /* rel->r_offset is not valid on mips? */ if (ELF_R_TYPE(ourrela.r_info) == R_TYPE(NONE)) ourrela.r_addend = 0; else #endif ourrela.r_addend = *(Elf_Word *) (obj->relocbase + rel->r_offset); if (_rtld_relocate_nonplt_object(obj, &ourrela) < 0) ok = 0; } } if (obj->rela != NULL) { /* Process the non-PLT relocations. */ const Elf_RelA *rela; for (rela = obj->rela; rela < obj->relalim; ++rela) { if (_rtld_relocate_nonplt_object(obj, rela) < 0) ok = 0; } } if (obj->textrel) { /* Re-protected the text segment. */ if (mprotect(obj->mapbase, obj->textsize, PROT_READ|PROT_EXEC) == -1) { _rtld_error("%s: Cannot write-protect text segment: %s", obj->path, xstrerror(errno)); return -1; } } /* Process the PLT relocations. */ if (obj->pltrel != NULL) { const Elf_Rel *rel; for (rel = obj->pltrel; rel < obj->pltrellim; ++rel) { Elf_RelA ourrela; ourrela.r_info = rel->r_info; ourrela.r_offset = rel->r_offset; ourrela.r_addend = *(Elf_Word *) (obj->relocbase + rel->r_offset); if (_rtld_relocate_plt_object(obj, &ourrela, bind_now) < 0) ok = 0; } } if (obj->pltrela != NULL) { const Elf_RelA *rela; for (rela = obj->pltrela; rela < obj->pltrelalim; ++rela) { if (_rtld_relocate_plt_object(obj, rela, bind_now) < 0) ok = 0; } } if (!ok) return -1; /* Set some sanity-checking numbers in the Obj_Entry. */ obj->magic = RTLD_MAGIC; obj->version = RTLD_VERSION; /* Fill in the dynamic linker entry points. */ obj->dlopen = _rtld_dlopen; obj->dlsym = _rtld_dlsym; obj->dlerror = _rtld_dlerror; obj->dlclose = _rtld_dlclose; /* Set the special PLTGOT entries. */ if (obj->pltgot != NULL) { #if defined(__i386__) obj->pltgot[1] = (Elf_Addr) obj; obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; #endif #if defined(__alpha__) /* This function will be called to perform the relocation. */ obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; /* Identify this shared object */ obj->pltgot[3] = (Elf_Addr) obj; #endif #if defined(__mips__) _rtld_relocate_mips_got(obj); obj->pltgot[0] = (Elf_Addr) &_rtld_bind_start; /* XXX only if obj->pltgot[1] & 0x80000000 ?? */ obj->pltgot[1] |= (Elf_Addr) obj; #endif #if defined(__powerpc__) _rtld_setup_powerpc_plt(obj); #endif #if defined(__sparc__) /* * PLTGOT is the PLT on the sparc. * The first entry holds the call the dynamic linker. * We construct a `call' instruction that transfers * to `_rtld_bind_start()'. * The second entry holds the object identification. * Note: each PLT entry is three words long. */ obj->pltgot[1] = 0x40000000 | ((Elf_Addr)&_rtld_bind_start - (Elf_Addr)&obj->pltgot[1]); obj->pltgot[3] = (Elf_Addr) obj; #endif } } return 0; }