diff options
Diffstat (limited to 'newlib/libc/sys/linux/dl/dl-reloc.c')
| -rw-r--r-- | newlib/libc/sys/linux/dl/dl-reloc.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/newlib/libc/sys/linux/dl/dl-reloc.c b/newlib/libc/sys/linux/dl/dl-reloc.c new file mode 100644 index 000000000..94163143e --- /dev/null +++ b/newlib/libc/sys/linux/dl/dl-reloc.c @@ -0,0 +1,213 @@ +/* Relocate a shared object and resolve its references to other loaded objects. + Copyright (C) 1995,96,97,98,99,2000,2001 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 + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <errno.h> +#include <libintl.h> +#include <stdlib.h> +#include <unistd.h> +#include <ldsodefs.h> +#include <sys/mman.h> +#include <sys/param.h> +#include <sys/types.h> +#include "dynamic-link.h" + +/* Statistics function. */ +unsigned long int _dl_num_cache_relocations; + + +void +_dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[], + int lazy, int consider_profiling) +{ + struct textrels + { + caddr_t start; + size_t len; + int prot; + struct textrels *next; + } *textrels = NULL; + /* Initialize it to make the compiler happy. */ + const char *errstring = NULL; + + if (l->l_relocated) + return; + + /* If DT_BIND_NOW is set relocate all references in this object. We + do not do this if we are profiling, of course. */ + if (!consider_profiling + && __builtin_expect (l->l_info[DT_BIND_NOW] != NULL, 0)) + lazy = 0; + + if (__builtin_expect (_dl_debug_mask & DL_DEBUG_RELOC, 0)) + _dl_printf ("\nrelocation processing: %s%s\n", + l->l_name[0] ? l->l_name : _dl_argv[0], lazy ? " (lazy)" : ""); + + /* DT_TEXTREL is now in level 2 and might phase out at some time. + But we rewrite the DT_FLAGS entry to a DT_TEXTREL entry to make + testing easier and therefore it will be available at all time. */ + if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0)) + { + /* Bletch. We must make read-only segments writable + long enough to relocate them. */ + const ElfW(Phdr) *ph; + for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph) + if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0) + { + struct textrels *newp; + + newp = (struct textrels *) alloca (sizeof (*newp)); + newp->len = (((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1) + & ~(_dl_pagesize - 1)) + - (ph->p_vaddr & ~(_dl_pagesize - 1))); + newp->start = ((ph->p_vaddr & ~(_dl_pagesize - 1)) + + (caddr_t) l->l_addr); + + if (mprotect (newp->start, newp->len, PROT_READ|PROT_WRITE) < 0) + { + errstring = N_("cannot make segment writable for relocation"); + call_error: + _dl_signal_error (errno, l->l_name, NULL, errstring); + } + +#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7 + newp->prot = (PF_TO_PROT + >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf; +#else + newp->prot = 0; + if (ph->p_flags & PF_R) + newp->prot |= PROT_READ; + if (ph->p_flags & PF_W) + newp->prot |= PROT_WRITE; + if (ph->p_flags & PF_X) + newp->prot |= PROT_EXEC; +#endif + newp->next = textrels; + textrels = newp; + } + } + + { + /* Do the actual relocation of the object's GOT and other data. */ + + /* String table object symbols. */ + const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]); + + /* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */ +#define RESOLVE_MAP(ref, version, r_type) \ + (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \ + ? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0) \ + && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class) \ + ? (++_dl_num_cache_relocations, \ + (*ref) = l->l_lookup_cache.ret, \ + l->l_lookup_cache.value) \ + : ({ lookup_t _lr; \ + int _tc = elf_machine_type_class (r_type); \ + l->l_lookup_cache.type_class = _tc; \ + l->l_lookup_cache.sym = (*ref); \ + _lr = ((version) != NULL && (version)->hash != 0 \ + ? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \ + l, (ref), scope, \ + (version), _tc, 0) \ + : _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), \ + scope, _tc, 0)); \ + l->l_lookup_cache.ret = (*ref); \ + l->l_lookup_cache.value = _lr; })) \ + : l) +#define RESOLVE(ref, version, r_type) \ + (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \ + ? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0) \ + && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class) \ + ? (++_dl_num_cache_relocations, \ + (*ref) = l->l_lookup_cache.ret, \ + l->l_lookup_cache.value) \ + : ({ lookup_t _lr; \ + int _tc = elf_machine_type_class (r_type); \ + l->l_lookup_cache.type_class = _tc; \ + l->l_lookup_cache.sym = (*ref); \ + _lr = ((version) != NULL && (version)->hash != 0 \ + ? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \ + l, (ref), scope, \ + (version), _tc, 0) \ + : _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), \ + scope, _tc, 0)); \ + l->l_lookup_cache.ret = (*ref); \ + l->l_lookup_cache.value = _lr; })) \ + : l->l_addr) + +#include "dynamic-link.h" + + ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling); + + if (__builtin_expect (consider_profiling, 0)) + { + /* Allocate the array which will contain the already found + relocations. If the shared object lacks a PLT (for example + if it only contains lead function) the l_info[DT_PLTRELSZ] + will be NULL. */ + if (l->l_info[DT_PLTRELSZ] == NULL) + { + errstring = N_("%s: profiler found no PLTREL in object %s\n"); + fatal: + _dl_fatal_printf (errstring, + _dl_argv[0] ?: "<program name unknown>", + l->l_name); + } + + l->l_reloc_result = + (ElfW(Addr) *) calloc (sizeof (ElfW(Addr)), + l->l_info[DT_PLTRELSZ]->d_un.d_val); + if (l->l_reloc_result == NULL) + { + errstring = N_("\ +%s: profiler out of memory shadowing PLTREL of %s\n"); + goto fatal; + } + } + } + + /* Mark the object so we know this work has been done. */ + l->l_relocated = 1; + + /* Undo the segment protection changes. */ + while (__builtin_expect (textrels != NULL, 0)) + { + if (mprotect (textrels->start, textrels->len, textrels->prot) < 0) + { + errstring = N_("cannot restore segment prot after reloc"); + goto call_error; + } + + textrels = textrels->next; + } +} + + +void +internal_function +_dl_reloc_bad_type (struct link_map *map, unsigned int type, int plt) +{ + /* XXX We cannot translate these messages. */ + static const char msg[2][32] = { "unexpected reloc type", + "unexpected PLT reloc type" }; + char msgbuf[sizeof (msg[0])]; + + strcpy (msgbuf, msg[plt]); + + _dl_signal_error (0, map->l_name, NULL, msgbuf); +} |