diff options
Diffstat (limited to 'elf/dl-runtime.c')
| -rw-r--r-- | elf/dl-runtime.c | 320 |
1 files changed, 52 insertions, 268 deletions
diff --git a/elf/dl-runtime.c b/elf/dl-runtime.c index ee2b8b5f6c..a0aecda2e8 100644 --- a/elf/dl-runtime.c +++ b/elf/dl-runtime.c @@ -1,5 +1,5 @@ /* On-demand PLT fixup for shared objects. - Copyright (C) 1995-2006, 2007 Free Software Foundation, Inc. + Copyright (C) 1995-2002, 2003, 2004 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -22,12 +22,8 @@ #include <alloca.h> #include <stdlib.h> #include <unistd.h> -#include <sys/param.h> #include <ldsodefs.h> -#include <sysdep-cancel.h> #include "dynamic-link.h" -#include <tls.h> - #if (!defined ELF_MACHINE_NO_RELA && !defined ELF_MACHINE_PLT_REL) \ || ELF_MACHINE_NO_REL @@ -55,15 +51,15 @@ function. */ #ifndef ELF_MACHINE_NO_PLT -DL_FIXUP_VALUE_TYPE -__attribute ((noinline)) ARCH_FIXUP_ATTRIBUTE -_dl_fixup ( +static ElfW(Addr) +__attribute ((used, noinline)) ARCH_FIXUP_ATTRIBUTE +fixup ( # ifdef ELF_MACHINE_RUNTIME_FIXUP_ARGS - ELF_MACHINE_RUNTIME_FIXUP_ARGS, + ELF_MACHINE_RUNTIME_FIXUP_ARGS, # endif - /* GKM FIXME: Fix trampoline to pass bounds so we can do - without the `__unbounded' qualifier. */ - struct link_map *__unbounded l, ElfW(Word) reloc_offset) + /* GKM FIXME: Fix trampoline to pass bounds so we can do + without the `__unbounded' qualifier. */ + struct link_map *__unbounded l, ElfW(Word) reloc_offset) { const ElfW(Sym) *const symtab = (const void *) D_PTR (l, l_info[DT_SYMTAB]); @@ -74,7 +70,7 @@ _dl_fixup ( const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (reloc->r_info)]; void *const rel_addr = (void *)(l->l_addr + reloc->r_offset); lookup_t result; - DL_FIXUP_VALUE_TYPE value; + ElfW(Addr) value; /* Sanity check that we're really looking at a PLT relocation. */ assert (ELFW(R_TYPE)(reloc->r_info) == ELF_MACHINE_JMP_SLOT); @@ -84,6 +80,8 @@ _dl_fixup ( if (__builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0) { const struct r_found_version *version = NULL; + // XXX Why exactly do we have the differentiation of the flags here? + int flags = DL_LOOKUP_ADD_DEPENDENCY; if (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL) { @@ -93,35 +91,27 @@ _dl_fixup ( version = &l->l_versions[ndx]; if (version->hash == 0) version = NULL; + else + flags = 0; } - /* We need to keep the scope around so do some locking. This is - not necessary for objects which cannot be unloaded or when - we are not using any threads (yet). */ - int flags = DL_LOOKUP_ADD_DEPENDENCY; - if (!RTLD_SINGLE_THREAD_P) - THREAD_GSCOPE_SET_FLAG (); - - result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym, l->l_scope, - version, ELF_RTYPE_CLASS_PLT, flags, NULL); - - /* We are done with the global scope. */ - if (!RTLD_SINGLE_THREAD_P) - THREAD_GSCOPE_RESET_FLAG (); + result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym, + l->l_scope, version, ELF_RTYPE_CLASS_PLT, + DL_LOOKUP_ADD_DEPENDENCY, NULL); /* Currently result contains the base load address (or link map) of the object that defines sym. Now add in the symbol offset. */ - value = DL_FIXUP_MAKE_VALUE (result, - sym ? (LOOKUP_VALUE_ADDRESS (result) - + sym->st_value) : 0); + value = (sym ? LOOKUP_VALUE_ADDRESS (result) + sym->st_value : 0); } else { /* We already found the symbol. The module (and therefore its load address) is also known. */ - value = DL_FIXUP_MAKE_VALUE (l, l->l_addr + sym->st_value); + value = l->l_addr + sym->st_value; +#ifdef DL_LOOKUP_RETURNS_MAP result = l; +#endif } /* And now perhaps the relocation addend. */ @@ -137,45 +127,45 @@ _dl_fixup ( #if !defined PROF && !defined ELF_MACHINE_NO_PLT && !__BOUNDED_POINTERS__ -DL_FIXUP_VALUE_TYPE -__attribute ((noinline)) ARCH_FIXUP_ATTRIBUTE -_dl_profile_fixup ( +static ElfW(Addr) +__attribute ((used, noinline)) ARCH_FIXUP_ATTRIBUTE +profile_fixup ( #ifdef ELF_MACHINE_RUNTIME_FIXUP_ARGS - ELF_MACHINE_RUNTIME_FIXUP_ARGS, + ELF_MACHINE_RUNTIME_FIXUP_ARGS, #endif - struct link_map *l, ElfW(Word) reloc_offset, - ElfW(Addr) retaddr, void *regs, long int *framesizep) + struct link_map *l, ElfW(Word) reloc_offset, ElfW(Addr) retaddr) { void (*mcount_fct) (ElfW(Addr), ElfW(Addr)) = INTUSE(_dl_mcount); + ElfW(Addr) *resultp; + lookup_t result; + ElfW(Addr) value; /* This is the address in the array where we store the result of previous relocations. */ - struct reloc_result *reloc_result - = &l->l_reloc_result[reloc_offset / sizeof (PLTREL)]; - DL_FIXUP_VALUE_TYPE *resultp = &reloc_result->addr; + resultp = &l->l_reloc_result[reloc_offset / sizeof (PLTREL)]; - DL_FIXUP_VALUE_TYPE value = *resultp; - if (DL_FIXUP_VALUE_CODE_ADDR (value) == 0) + value = *resultp; + if (value == 0) { /* This is the first time we have to relocate this object. */ const ElfW(Sym) *const symtab = (const void *) D_PTR (l, l_info[DT_SYMTAB]); - const char *strtab = (const char *) D_PTR (l, l_info[DT_STRTAB]); + const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]); const PLTREL *const reloc = (const void *) (D_PTR (l, l_info[DT_JMPREL]) + reloc_offset); - const ElfW(Sym) *refsym = &symtab[ELFW(R_SYM) (reloc->r_info)]; - const ElfW(Sym) *defsym = refsym; - lookup_t result; + const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (reloc->r_info)]; /* Sanity check that we're really looking at a PLT relocation. */ assert (ELFW(R_TYPE)(reloc->r_info) == ELF_MACHINE_JMP_SLOT); /* Look up the target symbol. If the symbol is marked STV_PROTECTED don't look in the global scope. */ - if (__builtin_expect (ELFW(ST_VISIBILITY) (refsym->st_other), 0) == 0) + if (__builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0) { const struct r_found_version *version = NULL; + // XXX Why exactly do we have the differentiation of the flags here? + int flags = DL_LOOKUP_ADD_DEPENDENCY; if (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL) { @@ -185,208 +175,38 @@ _dl_profile_fixup ( version = &l->l_versions[ndx]; if (version->hash == 0) version = NULL; + else + flags = 0; } - /* We need to keep the scope around so do some locking. This is - not necessary for objects which cannot be unloaded or when - we are not using any threads (yet). */ - int flags = DL_LOOKUP_ADD_DEPENDENCY; - if (!RTLD_SINGLE_THREAD_P) - THREAD_GSCOPE_SET_FLAG (); - - result = _dl_lookup_symbol_x (strtab + refsym->st_name, l, - &defsym, l->l_scope, version, - ELF_RTYPE_CLASS_PLT, flags, NULL); - - /* We are done with the global scope. */ - if (!RTLD_SINGLE_THREAD_P) - THREAD_GSCOPE_RESET_FLAG (); + result = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym, + l->l_scope, version, + ELF_RTYPE_CLASS_PLT, + DL_LOOKUP_ADD_DEPENDENCY, NULL); /* Currently result contains the base load address (or link map) of the object that defines sym. Now add in the symbol offset. */ - value = DL_FIXUP_MAKE_VALUE (result, - defsym != NULL - ? LOOKUP_VALUE_ADDRESS (result) - + defsym->st_value : 0); + value = (sym ? LOOKUP_VALUE_ADDRESS (result) + sym->st_value : 0); } else { /* We already found the symbol. The module (and therefore its load address) is also known. */ - value = DL_FIXUP_MAKE_VALUE (l, l->l_addr + refsym->st_value); + value = l->l_addr + sym->st_value; +#ifdef DL_LOOKUP_RETURNS_MAP result = l; +#endif } /* And now perhaps the relocation addend. */ value = elf_machine_plt_value (l, reloc, value); -#ifdef SHARED - /* Auditing checkpoint: we have a new binding. Provide the - auditing libraries the possibility to change the value and - tell us whether further auditing is wanted. */ - if (defsym != NULL && GLRO(dl_naudit) > 0) - { - reloc_result->bound = result; - /* Compute index of the symbol entry in the symbol table of - the DSO with the definition. */ - reloc_result->boundndx = (defsym - - (ElfW(Sym) *) D_PTR (result, - l_info[DT_SYMTAB])); - - /* Determine whether any of the two participating DSOs is - interested in auditing. */ - if ((l->l_audit_any_plt | result->l_audit_any_plt) != 0) - { - unsigned int altvalue = 0; - struct audit_ifaces *afct = GLRO(dl_audit); - /* Synthesize a symbol record where the st_value field is - the result. */ - ElfW(Sym) sym = *defsym; - sym.st_value = DL_FIXUP_VALUE_ADDR (value); - - /* Keep track whether there is any interest in tracing - the call in the lower two bits. */ - assert (DL_NNS * 2 <= sizeof (reloc_result->flags) * 8); - assert ((LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT) == 3); - reloc_result->enterexit = LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT; - - const char *strtab2 = (const void *) D_PTR (result, - l_info[DT_STRTAB]); - - for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) - { - /* XXX Check whether both DSOs must request action or - only one */ - if ((l->l_audit[cnt].bindflags & LA_FLG_BINDFROM) != 0 - && (result->l_audit[cnt].bindflags & LA_FLG_BINDTO) != 0) - { - unsigned int flags = altvalue; - if (afct->symbind != NULL) - { - uintptr_t new_value - = afct->symbind (&sym, reloc_result->boundndx, - &l->l_audit[cnt].cookie, - &result->l_audit[cnt].cookie, - &flags, - strtab2 + defsym->st_name); - if (new_value != (uintptr_t) sym.st_value) - { - altvalue = LA_SYMB_ALTVALUE; - sym.st_value = new_value; - } - } - - /* Remember the results for every audit library and - store a summary in the first two bits. */ - reloc_result->enterexit - &= flags & (LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT); - reloc_result->enterexit - |= ((flags & (LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT)) - << ((cnt + 1) * 2)); - } - else - /* If the bind flags say this auditor is not interested, - set the bits manually. */ - reloc_result->enterexit - |= ((LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT) - << ((cnt + 1) * 2)); - - afct = afct->next; - } - - reloc_result->flags = altvalue; - value = DL_FIXUP_ADDR_VALUE (sym.st_value); - } - else - /* Set all bits since this symbol binding is not interesting. */ - reloc_result->enterexit = (1u << DL_NNS) - 1; - } -#endif - /* Store the result for later runs. */ if (__builtin_expect (! GLRO(dl_bind_not), 1)) *resultp = value; } - /* By default we do not call the pltexit function. */ - long int framesize = -1; - -#ifdef SHARED - /* Auditing checkpoint: report the PLT entering and allow the - auditors to change the value. */ - if (DL_FIXUP_VALUE_CODE_ADDR (value) != 0 && GLRO(dl_naudit) > 0 - /* Don't do anything if no auditor wants to intercept this call. */ - && (reloc_result->enterexit & LA_SYMB_NOPLTENTER) == 0) - { - ElfW(Sym) *defsym = ((ElfW(Sym) *) D_PTR (reloc_result->bound, - l_info[DT_SYMTAB]) - + reloc_result->boundndx); - - /* Set up the sym parameter. */ - ElfW(Sym) sym = *defsym; - sym.st_value = DL_FIXUP_VALUE_ADDR (value); - - /* Get the symbol name. */ - const char *strtab = (const void *) D_PTR (reloc_result->bound, - l_info[DT_STRTAB]); - const char *symname = strtab + sym.st_name; - - /* Keep track of overwritten addresses. */ - unsigned int altvalue = reloc_result->flags; - - struct audit_ifaces *afct = GLRO(dl_audit); - for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) - { - if (afct->ARCH_LA_PLTENTER != NULL - && (reloc_result->enterexit - & (LA_SYMB_NOPLTENTER << (2 * (cnt + 1)))) == 0) - { - unsigned int flags = altvalue; - long int new_framesize = -1; - uintptr_t new_value - = afct->ARCH_LA_PLTENTER (&sym, reloc_result->boundndx, - &l->l_audit[cnt].cookie, - &reloc_result->bound->l_audit[cnt].cookie, - regs, &flags, symname, - &new_framesize); - if (new_value != (uintptr_t) sym.st_value) - { - altvalue = LA_SYMB_ALTVALUE; - sym.st_value = new_value; - } - - /* Remember the results for every audit library and - store a summary in the first two bits. */ - reloc_result->enterexit - |= ((flags & (LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT)) - << (2 * (cnt + 1))); - - if ((reloc_result->enterexit & (LA_SYMB_NOPLTEXIT - << (2 * (cnt + 1)))) - == 0 && new_framesize != -1 && framesize != -2) - { - /* If this is the first call providing information, - use it. */ - if (framesize == -1) - framesize = new_framesize; - /* If two pltenter calls provide conflicting information, - use the larger value. */ - else if (new_framesize != framesize) - framesize = MAX (new_framesize, framesize); - } - } - - afct = afct->next; - } - - value = DL_FIXUP_ADDR_VALUE (sym.st_value); - } -#endif - - /* Store the frame size information. */ - *framesizep = framesize; - - (*mcount_fct) (retaddr, DL_FIXUP_VALUE_CODE_ADDR (value)); + (*mcount_fct) (retaddr, value); return value; } @@ -394,45 +214,9 @@ _dl_profile_fixup ( #endif /* PROF && ELF_MACHINE_NO_PLT */ -#include <stdio.h> -void -ARCH_FIXUP_ATTRIBUTE -_dl_call_pltexit (struct link_map *l, ElfW(Word) reloc_offset, - const void *inregs, void *outregs) -{ -#ifdef SHARED - /* This is the address in the array where we store the result of previous - relocations. */ - // XXX Maybe the bound information must be stored on the stack since - // XXX with bind_not a new value could have been stored in the meantime. - struct reloc_result *reloc_result - = &l->l_reloc_result[reloc_offset / sizeof (PLTREL)]; - ElfW(Sym) *defsym = ((ElfW(Sym) *) D_PTR (reloc_result->bound, - l_info[DT_SYMTAB]) - + reloc_result->boundndx); - - /* Set up the sym parameter. */ - ElfW(Sym) sym = *defsym; - - /* Get the symbol name. */ - const char *strtab = (const void *) D_PTR (reloc_result->bound, - l_info[DT_STRTAB]); - const char *symname = strtab + sym.st_name; - - struct audit_ifaces *afct = GLRO(dl_audit); - for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) - { - if (afct->ARCH_LA_PLTEXIT != NULL - && (reloc_result->enterexit - & (LA_SYMB_NOPLTEXIT >> (2 * cnt))) == 0) - { - afct->ARCH_LA_PLTEXIT (&sym, reloc_result->boundndx, - &l->l_audit[cnt].cookie, - &reloc_result->bound->l_audit[cnt].cookie, - inregs, outregs, symname); - } +/* This macro is defined in dl-machine.h to define the entry point called + by the PLT. The `fixup' function above does the real work, but a little + more twiddling is needed to get the stack right and jump to the address + finally resolved. */ - afct = afct->next; - } -#endif -} +ELF_MACHINE_RUNTIME_TRAMPOLINE |