/* $OpenBSD: rtld_machine.c,v 1.39 2007/05/05 15:21:21 drahn Exp $ */ /* * Copyright (c) 1999 Dale Rahn * Copyright (c) 2001 Niklas Hallqvist * Copyright (c) 2001 Artur Grabowski * * 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. * * 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. */ /*- * Copyright (c) 2000 Eduardo Horvath. * Copyright (c) 1999 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Paul Kranenburg. * * 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 the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND 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 FOUNDATION OR 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. */ #define _DYN_LOADER #include #include #include #include #include #include #include "syscall.h" #include "archdep.h" #include "resolve.h" /* * 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_U 0x04000000 /* Unaligned */ #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_S| _RF_SZ(32) | _RF_RS(0), /* COPY */ _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* GLOB_DAT */ _RF_S| _RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */ _RF_A| _RF_B| _RF_SZ(64) | _RF_RS(0), /* RELATIVE */ _RF_S|_RF_A| _RF_U| _RF_SZ(32) | _RF_RS(0), /* UA_32 */ _RF_A| _RF_SZ(32) | _RF_RS(0), /* PLT32 */ _RF_A| _RF_SZ(32) | _RF_RS(10), /* HIPLT22 */ _RF_A| _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */ _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT32 */ _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PCPLT22 */ _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT10 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 10 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 11 */ _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* 64 */ _RF_S|_RF_A|/*extra*/ _RF_SZ(32) | _RF_RS(0), /* OLO10 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(42), /* HH22 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(32), /* HM10 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* LM22 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(42), /* PC_HH22 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(32), /* PC_HM10 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC_LM22 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP16 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP19 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_JMP */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 7 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 5 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 6 */ _RF_S|_RF_A|_RF_P| _RF_SZ(64) | _RF_RS(0), /* DISP64 */ _RF_A| _RF_SZ(64) | _RF_RS(0), /* PLT64 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HIX22 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LOX10 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(22), /* H44 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(12), /* M44 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* L44 */ _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* REGISTER */ _RF_S|_RF_A| _RF_U| _RF_SZ(64) | _RF_RS(0), /* UA64 */ _RF_S|_RF_A| _RF_U| _RF_SZ(16) | _RF_RS(0), /* UA16 */ }; #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_BASE_RELATIVE(t) ((reloc_target_flags[t] & _RF_B) != 0) #define RELOC_UNALIGNED(t) ((reloc_target_flags[t] & _RF_U) != 0) #define RELOC_USE_ADDEND(t) ((reloc_target_flags[t] & _RF_A) != 0) #define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff) #define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff) static long 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, _BM(32), -1, /* _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(22), _BM(10), _BM(22), /* _PC_HH22, _PC_HM10, _PC_LM22 */ _BM(16), _BM(19), /* _WDISP16, _WDISP19 */ -1, /* GLOB_JMP */ _BM(7), _BM(5), _BM(6) /* _7, _5, _6 */ -1, -1, /* DISP64, PLT64 */ _BM(22), _BM(13), /* HIX22, LOX10 */ _BM(22), _BM(10), _BM(13), /* H44, M44, L44 */ -1, -1, _BM(16), /* REGISTER, UA64, UA16 */ #undef _BM }; #define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t]) void _dl_reloc_plt(Elf_Word *where, Elf_Addr value, Elf_RelA *rela); void _dl_install_plt(Elf_Word *pltgot, Elf_Addr proc); int _dl_md_reloc(elf_object_t *object, int rel, int relasz) { long i; long numrela; long fails = 0; Elf_Addr loff; Elf_RelA *relas; struct load_list *llist; loff = object->load_offs; numrela = object->Dyn.info[relasz] / sizeof(Elf64_Rela); relas = (Elf64_Rela *)(object->Dyn.info[rel]); if (relas == NULL) return(0); /* * unprotect some segments if we need it. */ if ((object->dyn.textrel == 1) && (rel == DT_REL || rel == DT_RELA)) { for (llist = object->load_list; llist != NULL; llist = llist->next) { if (!(llist->prot & PROT_WRITE)) _dl_mprotect(llist->start, llist->size, llist->prot|PROT_WRITE); } } for (i = 0; i < numrela; i++, relas++) { Elf_Addr *where, value, ooff, mask; Elf_Word type; const Elf_Sym *sym, *this; const char *symn; type = ELF_R_TYPE(relas->r_info); if (type == R_TYPE(NONE)) continue; if (type == R_TYPE(JMP_SLOT) && rel != DT_JMPREL) continue; where = (Elf_Addr *)(relas->r_offset + loff); if (RELOC_USE_ADDEND(type)) value = relas->r_addend; else value = 0; sym = NULL; symn = NULL; if (RELOC_RESOLVE_SYMBOL(type)) { sym = object->dyn.symtab; sym += ELF_R_SYM(relas->r_info); symn = object->dyn.strtab + sym->st_name; if (sym->st_shndx != SHN_UNDEF && ELF_ST_BIND(sym->st_info) == STB_LOCAL) { value += loff; } else { this = NULL; ooff = _dl_find_symbol_bysym(object, ELF_R_SYM(relas->r_info), &this, SYM_SEARCH_ALL|SYM_WARNNOTFOUND| ((type == R_TYPE(JMP_SLOT)) ? SYM_PLT : SYM_NOTPLT), sym, NULL); if (this == NULL) { resolve_failed: if (ELF_ST_BIND(sym->st_info) != STB_WEAK) fails++; continue; } value += (Elf_Addr)(ooff + this->st_value); } } if (type == R_TYPE(JMP_SLOT)) { _dl_reloc_plt((Elf_Word *)where, value, relas); continue; } if (type == R_TYPE(COPY)) { void *dstaddr = where; const void *srcaddr; const Elf_Sym *dstsym = sym, *srcsym = NULL; size_t size = dstsym->st_size; Elf_Addr soff; soff = _dl_find_symbol(symn, &srcsym, SYM_SEARCH_OTHER|SYM_WARNNOTFOUND|SYM_NOTPLT, dstsym, object, NULL); if (srcsym == NULL) goto resolve_failed; srcaddr = (void *)(soff + srcsym->st_value); _dl_bcopy(srcaddr, dstaddr, size); continue; } if (RELOC_PC_RELATIVE(type)) value -= (Elf_Addr)where; if (RELOC_BASE_RELATIVE(type)) value += loff; mask = RELOC_VALUE_BITMASK(type); value >>= RELOC_VALUE_RIGHTSHIFT(type); value &= mask; if (RELOC_UNALIGNED(type)) { /* Handle unaligned relocations. */ Elf_Addr tmp = 0; char *ptr = (char *)where; int i, size = RELOC_TARGET_SIZE(type)/8; /* Read it in one byte at a time. */ for (i=0; i> (8*i)) & 0xff); } else if (RELOC_TARGET_SIZE(type) > 32) { *where &= ~mask; *where |= value; } else { Elf32_Addr *where32 = (Elf32_Addr *)where; *where32 &= ~mask; *where32 |= value; } } /* reprotect the unprotected segments */ if ((object->dyn.textrel == 1) && (rel == DT_REL || rel == DT_RELA)) { for (llist = object->load_list; llist != NULL; llist = llist->next) { if (!(llist->prot & PROT_WRITE)) _dl_mprotect(llist->start, llist->size, llist->prot); } } return (fails); } /* * Instruction templates: */ #define BAA 0x10400000 /* ba,a %xcc, 0 */ #define SETHI 0x03000000 /* sethi %hi(0), %g1 */ #define JMP 0x81c06000 /* jmpl %g1+%lo(0), %g0 */ #define NOP 0x01000000 /* sethi %hi(0), %g0 */ #define OR 0x82806000 /* or %g1, 0, %g1 */ #define XOR 0x82c06000 /* xor %g1, 0, %g1 */ #define MOV71 0x8283a000 /* or %o7, 0, %g1 */ #define MOV17 0x9c806000 /* or %g1, 0, %o7 */ #define CALL 0x40000000 /* call 0 */ #define SLLX 0x8b407000 /* sllx %g1, 0, %g1 */ #define SETHIG5 0x0b000000 /* sethi %hi(0), %g5 */ #define ORG5 0x82804005 /* or %g1, %g5, %g1 */ /* %hi(v) with variable shift */ #define HIVAL(v, s) (((v) >> (s)) & 0x003fffff) #define LOVAL(v) ((v) & 0x000003ff) void _dl_reloc_plt(Elf_Word *where, Elf_Addr value, Elf_RelA *rela) { Elf_Addr offset; /* * At the PLT entry pointed at by `where', we now construct * a direct transfer to the now fully resolved function * address. * * A PLT entry is supposed to start by looking like this: * * sethi %hi(. - .PLT0), %g1 * ba,a %xcc, .PLT1 * nop * nop * nop * nop * nop * nop * * When we replace these entries we start from the second * entry and do it in reverse order so the last thing we * do is replace the branch. That allows us to change this * atomically. * * We now need to find out how far we need to jump. We * have a choice of several different relocation techniques * which are increasingly expensive. */ offset = ((Elf_Addr)where) - value; if (rela->r_addend) { Elf_Addr *ptr = (Elf_Addr *)where; /* * This entry is >32768. Just replace the pointer. */ ptr[0] = value; } else if (offset <= (1L<<20) && offset >= -(1L<<20)) { /* * We're within 1MB -- we can use a direct branch insn. * * We can generate this pattern: * * sethi %hi(. - .PLT0), %g1 * ba,a %xcc, addr * nop * nop * nop * nop * nop * nop * */ where[1] = BAA | ((offset >> 2) &0x3fffff); __asm __volatile("iflush %0+4" : : "r" (where)); } else if (value >= 0 && value < (1L<<32)) { /* * We're withing 32-bits of address zero. * * The resulting code in the jump slot is: * * sethi %hi(. - .PLT0), %g1 * sethi %hi(addr), %g1 * jmp %g1+%lo(addr) * nop * nop * nop * nop * nop * */ where[2] = JMP | LOVAL(value); where[1] = SETHI | HIVAL(value, 10); __asm __volatile("iflush %0+8" : : "r" (where)); __asm __volatile("iflush %0+4" : : "r" (where)); } else if (value <= 0 && value > -(1L<<32)) { /* * We're withing 32-bits of address -1. * * The resulting code in the jump slot is: * * sethi %hi(. - .PLT0), %g1 * sethi %hix(addr), %g1 * xor %g1, %lox(addr), %g1 * jmp %g1 * nop * nop * nop * nop * */ where[3] = JMP; where[2] = XOR | ((~value) & 0x00001fff); where[1] = SETHI | HIVAL(~value, 10); __asm __volatile("iflush %0+12" : : "r" (where)); __asm __volatile("iflush %0+8" : : "r" (where)); __asm __volatile("iflush %0+4" : : "r" (where)); } else if (offset <= (1L<<32) && offset >= -((1L<<32) - 4)) { /* * We're withing 32-bits -- we can use a direct call insn * * The resulting code in the jump slot is: * * sethi %hi(. - .PLT0), %g1 * mov %o7, %g1 * call (.+offset) * mov %g1, %o7 * nop * nop * nop * nop * */ where[3] = MOV17; where[2] = CALL | ((offset >> 4) & 0x3fffffff); where[1] = MOV71; __asm __volatile("iflush %0+12" : : "r" (where)); __asm __volatile("iflush %0+8" : : "r" (where)); __asm __volatile("iflush %0+4" : : "r" (where)); } else if (offset >= 0 && offset < (1L<<44)) { /* * We're withing 44 bits. We can generate this pattern: * * The resulting code in the jump slot is: * * sethi %hi(. - .PLT0), %g1 * sethi %h44(addr), %g1 * or %g1, %m44(addr), %g1 * sllx %g1, 12, %g1 * jmp %g1+%l44(addr) * nop * nop * nop * */ where[4] = JMP | LOVAL(offset); where[3] = SLLX | 12; where[2] = OR | (((offset) >> 12) & 0x00001fff); where[1] = SETHI | HIVAL(offset, 22); __asm __volatile("iflush %0+16" : : "r" (where)); __asm __volatile("iflush %0+12" : : "r" (where)); __asm __volatile("iflush %0+8" : : "r" (where)); __asm __volatile("iflush %0+4" : : "r" (where)); } else if (offset < 0 && offset > -(1L<<44)) { /* * We're withing 44 bits. We can generate this pattern: * * The resulting code in the jump slot is: * * sethi %hi(. - .PLT0), %g1 * sethi %h44(-addr), %g1 * xor %g1, %m44(-addr), %g1 * sllx %g1, 12, %g1 * jmp %g1+%l44(addr) * nop * nop * nop * */ where[4] = JMP | LOVAL(offset); where[3] = SLLX | 12; where[2] = XOR | (((~offset) >> 12) & 0x00001fff); where[1] = SETHI | HIVAL(~offset, 22); __asm __volatile("iflush %0+16" : : "r" (where)); __asm __volatile("iflush %0+12" : : "r" (where)); __asm __volatile("iflush %0+8" : : "r" (where)); __asm __volatile("iflush %0+4" : : "r" (where)); } else { /* * We need to load all 64-bits * * The resulting code in the jump slot is: * * sethi %hi(. - .PLT0), %g1 * sethi %hh(addr), %g1 * sethi %lm(addr), %g5 * or %g1, %hm(addr), %g1 * sllx %g1, 32, %g1 * or %g1, %g5, %g1 * jmp %g1+%lo(addr) * nop * */ where[6] = JMP | LOVAL(value); where[5] = ORG5; where[4] = SLLX | 12; where[3] = OR | LOVAL((value) >> 32); where[2] = SETHIG5 | HIVAL(value, 10); where[1] = SETHI | HIVAL(value, 42); __asm __volatile("iflush %0+24" : : "r" (where)); __asm __volatile("iflush %0+20" : : "r" (where)); __asm __volatile("iflush %0+16" : : "r" (where)); __asm __volatile("iflush %0+12" : : "r" (where)); __asm __volatile("iflush %0+8" : : "r" (where)); __asm __volatile("iflush %0+4" : : "r" (where)); } } /* * Resolve a symbol at run-time. */ Elf_Addr _dl_bind(elf_object_t *object, int index) { Elf_RelA *rela; Elf_Word *addr; Elf_Addr ooff; const Elf_Sym *sym, *this; const char *symn; sigset_t omask, nmask; rela = (Elf_RelA *)(object->Dyn.info[DT_JMPREL]); if (ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)) { /* * XXXX * * The first four PLT entries are reserved. There * is some disagreement whether they should have * associated relocation entries. Both the SPARC * 32-bit and 64-bit ELF specifications say that * they should have relocation entries, but the * 32-bit SPARC binutils do not generate them, * and now the 64-bit SPARC binutils have stopped * generating them too. * * So, to provide binary compatibility, we will * check the first entry, if it is reserved it * should not be of the type JMP_SLOT. If it * is JMP_SLOT, then the 4 reserved entries were * not generated and our index is 4 entries too far. */ index -= 4; } rela += index; sym = object->dyn.symtab; sym += ELF64_R_SYM(rela->r_info); symn = object->dyn.strtab + sym->st_name; addr = (Elf_Word *)(object->load_offs + rela->r_offset); this = NULL; ooff = _dl_find_symbol(symn, &this, SYM_SEARCH_ALL|SYM_WARNNOTFOUND|SYM_PLT, sym, object, NULL); if (this == NULL) { _dl_printf("lazy binding failed!\n"); *((int *)0) = 0; /* XXX */ } /* if PLT is protected, allow the write */ if (object->plt_size != 0) { sigfillset(&nmask); _dl_sigprocmask(SIG_BLOCK, &nmask, &omask); _dl_thread_bind_lock(0); _dl_mprotect((void*)object->plt_start, object->plt_size, PROT_READ|PROT_WRITE|PROT_EXEC); } _dl_reloc_plt(addr, ooff + this->st_value, rela); /* if PLT is (to be protected), change back to RO/X */ if (object->plt_size != 0) { _dl_mprotect((void*)object->plt_start, object->plt_size, PROT_READ|PROT_EXEC); _dl_thread_bind_lock(1); _dl_sigprocmask(SIG_SETMASK, &omask, NULL); } return ooff + this->st_value; } /* * Install rtld function call into this PLT slot. */ #define SAVE 0x9de3bf50 #define SETHI_l0 0x21000000 #define SETHI_l1 0x23000000 #define OR_l0_l0 0xa0142000 #define SLLX_l0_32_l0 0xa12c3020 #define OR_l0_l1_l0 0xa0140011 #define JMPL_l0_o1 0x93c42000 #define MOV_g1_o0 0x90100001 void _dl_install_plt(Elf_Word *pltgot, Elf_Addr proc) { pltgot[0] = SAVE; pltgot[1] = SETHI_l0 | HIVAL(proc, 42); pltgot[2] = SETHI_l1 | HIVAL(proc, 10); pltgot[3] = OR_l0_l0 | LOVAL((proc) >> 32); pltgot[4] = SLLX_l0_32_l0; pltgot[5] = OR_l0_l1_l0; pltgot[6] = JMPL_l0_o1 | LOVAL(proc); pltgot[7] = MOV_g1_o0; } void _dl_bind_start_0(long, long); void _dl_bind_start_1(long, long); /* * Relocate the Global Offset Table (GOT). */ void _dl_md_reloc_got(elf_object_t *object, int lazy) { Elf_Addr *pltgot = (Elf_Addr *)object->Dyn.info[DT_PLTGOT]; Elf_Word *entry = (Elf_Word *)pltgot; Elf_Addr ooff; Elf_Addr plt_addr; const Elf_Sym *this; if (object->Dyn.info[DT_PLTREL] != DT_RELA) return; object->got_addr = NULL; object->got_size = 0; this = NULL; ooff = _dl_find_symbol("__got_start", &this, SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL); if (this != NULL) object->got_addr = ooff + this->st_value; this = NULL; ooff = _dl_find_symbol("__got_end", &this, SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL); if (this != NULL) object->got_size = ooff + this->st_value - object->got_addr; plt_addr = 0; object->plt_size = 0; this = NULL; ooff = _dl_find_symbol("__plt_start", &this, SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL); if (this != NULL) plt_addr = ooff + this->st_value; this = NULL; ooff = _dl_find_symbol("__plt_end", &this, SYM_SEARCH_OBJ|SYM_NOWARNNOTFOUND|SYM_PLT, NULL, object, NULL); if (this != NULL) object->plt_size = ooff + this->st_value - plt_addr; if (object->got_addr == NULL) object->got_start = NULL; else { object->got_start = ELF_TRUNC(object->got_addr, _dl_pagesz); object->got_size += object->got_addr - object->got_start; object->got_size = ELF_ROUND(object->got_size, _dl_pagesz); } if (plt_addr == NULL) object->plt_start = NULL; else { object->plt_start = ELF_TRUNC(plt_addr, _dl_pagesz); object->plt_size += plt_addr - object->plt_start; object->plt_size = ELF_ROUND(object->plt_size, _dl_pagesz); } if (!lazy) { _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ); } else { _dl_install_plt(&entry[0], (Elf_Addr)&_dl_bind_start_0); _dl_install_plt(&entry[8], (Elf_Addr)&_dl_bind_start_1); pltgot[8] = (Elf_Addr)object; } if (object->got_size != 0) _dl_mprotect((void*)object->got_addr, object->got_size, PROT_READ); if (object->plt_size != 0) _dl_mprotect((void*)object->plt_start, object->plt_size, PROT_READ|PROT_EXEC); }