diff options
Diffstat (limited to 'elf')
| -rw-r--r-- | elf/Makefile | 2 | ||||
| -rw-r--r-- | elf/dladdr.c | 88 | ||||
| -rw-r--r-- | elf/dlfcn.h | 10 |
3 files changed, 99 insertions, 1 deletions
diff --git a/elf/Makefile b/elf/Makefile index 8f34a9cfd2..354fbbcc70 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -25,7 +25,7 @@ routines := init-first extra-libs = libelf libdl libelf-routines := elf_hash -libdl-routines := dlopen dlclose dlsym dlerror +libdl-routines := dlopen dlclose dlsym dlerror dladdr libdl-inhibit-o = $(filter-out .so,$(object-suffixes)) # Build only shared. rtld-routines := rtld $(addprefix dl-,minimal load lookup object reloc \ diff --git a/elf/dladdr.c b/elf/dladdr.c new file mode 100644 index 0000000000..166952ac46 --- /dev/null +++ b/elf/dladdr.c @@ -0,0 +1,88 @@ +/* dladdr -- Locate the shared object symbol nearest a given address. +Copyright (C) 1996 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 Library General Public License as +published by the Free Software Foundation; either version 2 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 +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#include <stddef.h> +#include <link.h> +#include <dlfcn.h> +#include <setjmp.h> + + +int +dladdr (void *address, Dl_info *info) +{ + const Elf32_Addr addr = (Elf32_Addr) address; + struct link_map *l, *match; + const Elf32_Sym *symtab, *matchsym; + const char *strtab; + Elf32_Word symidx; + + /* Find the highest-addressed object that ADDRESS is not below. */ + match = NULL; + for (l = _dl_loaded; l; l = l->l_next) + if (addr >= l->l_addr && !match || match->l_addr < l->l_addr) + match = l; + + if (match) + { + /* We know ADDRESS lies within MATCH if in any shared object. + Make sure it isn't past the end of MATCH's segments. */ + size_t n = match->l_phnum; + do + --n; + while (match->l_phdr[n].p_type != PT_LOAD); + if (addr >= (match->l_addr + + match->l_phdr[n].p_vaddr + match->l_phdr[n].p_memsz)) + /* Off the end of the highest-addressed shared object. */ + return 0; + } + else + return 0; + + /* Now we know what object the address lies in. */ + info->dli_fname = match->l_name; + info->dli_fbase = (void *) match->l_addr; + + symtab = ((void *) match->l_addr + match->l_info[DT_SYMTAB]->d_un.d_ptr); + strtab = ((void *) match->l_addr + match->l_info[DT_STRTAB]->d_un.d_ptr); + + /* We assume that the string table follows the symbol table, because + there is no way in ELF to know the size of the dynamic symbol table!! */ + for (matchsym = NULL; (void *) symtab < (void *) strtab; ++symtab) + if (addr >= match->l_addr + symtab->st_value && !matchsym || + matchsym->st_value < symtab->st_value && + ELF32_ST_BIND (symtab->st_info) == STB_GLOBAL || + ELF32_ST_BIND (symtab->st_info) == STB_WEAK) + matchsym = symtab; + + if (matchsym) + { + /* We found a symbol close by. Fill in its name and exact address. */ + info->dli_sname = strtab + matchsym->st_name; + info->dli_saddr = (void *) (match->l_addr + matchsym->st_value); + } + else + { + /* No symbol matches. We return only the containing object. */ + info->dli_sname = NULL; + info->dli_saddr = NULL; + } + + return 1; +} + diff --git a/elf/dlfcn.h b/elf/dlfcn.h index 8d19b8b847..b26a38fb68 100644 --- a/elf/dlfcn.h +++ b/elf/dlfcn.h @@ -48,5 +48,15 @@ extern void *dlsym (void *__handle, const char *__name); the error string so that a following call returns null. */ extern char *dlerror (void); +/* Fill in *INFO with the following information about ADDRESS. + Returns 0 iff no shared object's segments contain that address. */ +typedef struct + { + const char *dli_fname; /* File name of defining object. */ + void *dli_fbase; /* Load address of that object. */ + const char *dli_sname; /* Name of nearest symbol. */ + void *dli_saddr; /* Exact value of nearest symbol. */ + } Dl_info; +extern int dladdr (void *__address, Dl_info *__info); #endif /* dlfcn.h */ |