From 266180eb985e14fa9f77cfd3b41e9211e9986162 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Mon, 10 Jun 1996 10:18:47 +0000 Subject: Mon Jun 10 06:14:03 1996 Roland McGrath * sysdeps/mach/hurd/dl-sysdep.c (__open): Define this instead of open. (__close, __mmap): Likewise define with __ names now. Mon Jun 10 05:13:18 1996 Roland McGrath * elf/dl-support.c: New file. * elf/Makefile (CFLAGS-dl-support.c): New variable. (routines, elide-routines.so): Add dl-support. * elf/dl-minimal.c (_dl_pagesize): Remove common defn. * elf/dl-load.c (_dl_pagesize): Define it here. (_dl_map_object_from_fd): Initialize it if zero. * elf/link.h (_dl_pagesize): Remove const. Sun Jun 9 04:04:26 1996 Roland McGrath * elf/Makefile (routines): Add dl-symbol. * elf/dl-lookup.c (_dl_symbol_value): Moved to ... * elf/dl-symbol.c: New file. * elf/elf.h (Elf32_Xword, Elf32_Sxword): New types. (Elf32_Section, Elf64_Section): New types, 16 bits. (Elf32_Sym, Elf64_Sym): Use it. * elf/dl-deps.c (_dl_open): Moved to ... * elf/dl-open.c: New file. * Makefile (routines): Add dl-open. * elf/Makefile (dl-routines): New variable. (routines): Add $(dl-routines). (elide-routines.so): New variable, set to $(dl-routines). (libdl-inhibit-o): Variable removed; build all flavors of -ldl. (rtld-routines): All but rtld, dl-sysdep, and dl-minimal moved to $(dl-routines). * elf/dl-lookup.c (_dl_lookup_symbol): Remove magic symbol grokage. * elf/dladdr.c: Use ELFW(ST_BIND) in place of ELF32_ST_BIND. * elf/dl-load.c (open_path): Use __ names for open and close. Avoid using strdup. (_dl_map_object): Likewise. (_dl_map_object_from_fd): Use __ names for mmap, munmap, and mprotect. * elf/dl-minimal.c (malloc): Likewise. * elf/dl-reloc.c (_dl_relocate_object): Likewise. * elf/dl-minimal.c (_dl_pagesize): New variable. (malloc): Use that instead of a static variable. * elf/dl-reloc.c (_dl_relocate_object): Use _dl_pagesize instead of calling getpagesize. * elf/dl-load.c (_dl_map_object_from_fd): Likewise. * elf/link.h: Declare _dl_pagesize. * elf/rtld.c (dl_r_debug): Renamed to _dl_r_debug. * elf/link.h (struct link_map): Use Half for l_phnum instead of Word. * elf/rtld.c (dl_main): Use Half for phdr count arg. (_dl_sysdep_start): Update prototype of DL_MAIN function ptr arg. * elf/dl-load.c (_dl_map_object_from_fd): Use explicit Elf32_Word to extract 4-byte magic number, not ElfW(Word). Match EI_CLASS against native wordsize, either 32 or 64. * elf/elf.h (Elf64_Byte, Elf64_Section): Typedefs removed. In C a char is always a byte, no need for a typedef. Section indices are 16-bit quantities in elf64, which already have a typedef Elf64_Half. Remove partial -lelf implementation. There is now a separately-distributed `libelf' package that implements it. * elf/dl-lookup.c: Don't #include any more. (_dl_elf_hash): New function, moved from libelf.h:elf_hash. (_dl_lookup_symbol): Use it instead of elf_hash. * elf/libelf.h: File removed. * elf/elf_hash.c: File removed. * elf/Makefile (headers): Remove libelf.h. (extra-libs): Remove libelf. (libelf-routines): Variable removed. * elf/Makefile (libdl.so): Remove commands from this target. The implicit rule commands are correct, this explicit rule just serves to add some dependencies. * elf/dl-lookup.c (_dl_lookup_symbol): Use ELFW(ST_TYPE) in place of ELF32_ST_TYPE. Likewise ST_BIND. * elf/do-rel.h (elf_dynamic_do_rel): Likewise R_SYM. * elf/link.h (ElfW): New macro for wordsize-independent ElfXX_* type naming. (ELFW): New macro, likewise for ELFXX_* macro naming. (_ElfW, _ElfW_1): New macros, subroutines of ElfW and ELF. Sat Jun 8 20:52:38 1996 Roland McGrath * elf/link.h, elf/do-rel.h, elf/dynamic-link.h, elf/dl-deps.c, elf/dl-init.c, elf/dl-load.c, elf/dl-lookup.c, elf/dl-reloc.c, elf/dl-runtime.c, elf/dladdr.c, elf/dlclose.c, elf/dlsym.c, elf/linux-compat.c, elf/rtld.c: Change all uses of `Elf32_XXX' to `ElfW(XXX)' for wordsize-independence. Sat Jun 8 20:50:42 1996 Richard Henderson * elf/elf.h: Move Elf64_* types in parity with Elf32 counterparts. (Elf64_auxv_t): New type. (EM_ALPHA, R_ALPHA_*): New macros for elf64-alpha format. --- elf/dl-lookup.c | 103 +++++++++++++++++++++++--------------------------------- 1 file changed, 43 insertions(+), 60 deletions(-) (limited to 'elf/dl-lookup.c') diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index 1049639..0674253 100644 --- a/elf/dl-lookup.c +++ b/elf/dl-lookup.c @@ -18,27 +18,48 @@ not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include -#include #include #include + +/* This is the hashing function specified by the ELF ABI. */ +static inline unsigned +_dl_elf_hash (const char *name) +{ + unsigned long int hash = 0; + while (*name != '\0') + { + unsigned long int hi; + hash = (hash << 4) + *name++; + hi = hash & 0xf0000000; + if (hi != 0) + { + hash ^= hi >> 24; + /* The ELF ABI says `hash &= ~hi', but this is equivalent + in this case and on some machines one insn instead of two. */ + hash ^= hi; + } + } + return hash; +} + /* Search loaded objects' symbol tables for a definition of the symbol UNDEF_NAME. The chosen value can't be RELOC_ADDR. If NOPLT is nonzero, then a PLT entry cannot satisfy the reference; some different binding must be found. */ -Elf32_Addr -_dl_lookup_symbol (const char *undef_name, const Elf32_Sym **ref, +ElfW(Addr) +_dl_lookup_symbol (const char *undef_name, const ElfW(Sym) **ref, struct link_map *symbol_scope[2], const char *reference_name, - Elf32_Addr reloc_addr, + ElfW(Addr) reloc_addr, int noplt) { - unsigned long int hash = elf_hash (undef_name); + const unsigned long int hash = _dl_elf_hash (undef_name); struct { - Elf32_Addr a; - const Elf32_Sym *s; + ElfW(Addr) a; + const ElfW(Sym) *s; } weak_value = { 0, NULL }; size_t i; struct link_map **scope, *map; @@ -48,9 +69,9 @@ _dl_lookup_symbol (const char *undef_name, const Elf32_Sym **ref, if (*scope) for (i = 0; i < (*scope)->l_nsearchlist; ++i) { - const Elf32_Sym *symtab; + const ElfW(Sym) *symtab; const char *strtab; - Elf32_Word symidx; + ElfW(Word) symidx; map = (*scope)->l_searchlist[i]; @@ -63,7 +84,7 @@ _dl_lookup_symbol (const char *undef_name, const Elf32_Sym **ref, symidx != STN_UNDEF; symidx = map->l_chain[symidx]) { - const Elf32_Sym *sym = &symtab[symidx]; + const ElfW(Sym) *sym = &symtab[symidx]; if (sym->st_value == 0 || /* No value. */ /* Cannot resolve to the location being filled in. */ @@ -71,7 +92,7 @@ _dl_lookup_symbol (const char *undef_name, const Elf32_Sym **ref, (noplt && sym->st_shndx == SHN_UNDEF)) /* Reject PLT. */ continue; - switch (ELF32_ST_TYPE (sym->st_info)) + switch (ELFW(ST_TYPE) (sym->st_info)) { case STT_NOTYPE: case STT_FUNC: @@ -86,7 +107,7 @@ _dl_lookup_symbol (const char *undef_name, const Elf32_Sym **ref, /* Not the symbol we are looking for. */ continue; - switch (ELF32_ST_BIND (sym->st_info)) + switch (ELFW(ST_BIND) (sym->st_info)) { case STB_GLOBAL: /* Global definition. Just what we need. */ @@ -108,41 +129,15 @@ _dl_lookup_symbol (const char *undef_name, const Elf32_Sym **ref, } } - if (weak_value.s == NULL && ELF32_ST_BIND ((*ref)->st_info) != STB_WEAK) + if (weak_value.s == NULL && ELFW(ST_BIND) ((*ref)->st_info) != STB_WEAK) { - /* The symbol was not defined by any object in scope. To allow - access to dynamic linker functionality without using -ldl and - thereby brining the dynamic linker's symbols into scope, we - recognize a few magical symbol names and resolve them to the - addresses of functions inside the dynamic linker. */ - - struct magic - { - unsigned long int hash; - const char *name; - Elf32_Addr value; - }; - static struct magic magic[] = - { - { 0xd6a2a5e, "_GNU_libc_dl_open", (Elf32_Addr) &_dl_open }, -/* { 0x69ef845, "_GNU_libc_dl_close", (Elf32_Addr) &_dl_close },*/ - { 0xae4d63c, "_GNU_libc_dl_symbol", (Elf32_Addr) &_dl_symbol_value }, - { 0, NULL, 0 } - }; - struct magic *m; - - for (m = magic; m->hash; ++m) - if (hash == m->hash && !strcmp (undef_name, m->name)) - return m->value; - - { - const char msg[] = "undefined symbol: "; - char buf[sizeof msg + strlen (undef_name)]; - memcpy (buf, msg, sizeof msg - 1); - memcpy (&buf[sizeof msg - 1], undef_name, - sizeof buf - sizeof msg + 1); - _dl_signal_error (0, reference_name, buf); - } + /* We could find no value for a strong reference. */ + const char msg[] = "undefined symbol: "; + char buf[sizeof msg + strlen (undef_name)]; + memcpy (buf, msg, sizeof msg - 1); + memcpy (&buf[sizeof msg - 1], undef_name, + sizeof buf - sizeof msg + 1); + _dl_signal_error (0, reference_name, buf); } *ref = weak_value.s; @@ -155,23 +150,11 @@ _dl_lookup_symbol (const char *undef_name, const Elf32_Sym **ref, void _dl_setup_hash (struct link_map *map) { - Elf32_Word *hash = (void *) map->l_addr + map->l_info[DT_HASH]->d_un.d_ptr; - Elf32_Word nchain; + ElfW(Word) *hash = (void *) map->l_addr + map->l_info[DT_HASH]->d_un.d_ptr; + ElfW(Word) nchain; map->l_nbuckets = *hash++; nchain = *hash++; map->l_buckets = hash; hash += map->l_nbuckets; map->l_chain = hash; } - -/* Look up symbol NAME in MAP's scope and return its run-time address. */ - -Elf32_Addr -_dl_symbol_value (struct link_map *map, const char *name) -{ - Elf32_Addr loadbase; - const Elf32_Sym *ref = NULL; - struct link_map *scope[2] = { map, NULL }; - loadbase = _dl_lookup_symbol (name, &ref, scope, map->l_name, 0, 0); - return loadbase + ref->st_value; -} -- cgit v1.1