[uClibc-cvs] uClibc/ldso/ldso hash.c,1.14,1.15
Erik Andersen
andersen at uclibc.org
Sat Feb 7 12:05:18 UTC 2004
Update of /var/cvs/uClibc/ldso/ldso
In directory nail:/tmp/cvs-serv31632
Modified Files:
hash.c
Log Message:
Joakim Tjernlund writes:
Hi again
All dltest* and test* programs pass for me.
uClibc ld.so resolves according to the OLD weak symbol handling.
I have tried to use the new scheme as well, but that segfaults in all
cases but test3.
Index: hash.c
===================================================================
RCS file: /var/cvs/uClibc/ldso/ldso/hash.c,v
retrieving revision 1.14
retrieving revision 1.15
diff -u -d -r1.14 -r1.15
--- hash.c 19 Aug 2003 13:11:06 -0000 1.14
+++ hash.c 7 Feb 2004 12:05:16 -0000 1.15
@@ -1,12 +1,12 @@
/* vi: set sw=4 ts=4: */
-/* Program to load an ELF binary on a linux system, and run it
+/*
+ * Program to load an ELF binary on a linux system, and run it
* after resolving ELF shared library symbols
*
- * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
+ * Copyright (C) 2004 by Joakim Tjernlund <joakim.tjernlund at lumentis.se>
+ * Copyright (C) 2000-2004 by Erik Andersen <andersen at codpoet.org>
+ * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
* David Engel, Hongjiu Lu and Mitch D'Souza
- * Copyright (C) 2001-2002, Erik Andersen
- *
- * All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -35,10 +35,9 @@
/*
* This is the start of the linked list that describes all of the files present
- * in the system with pointers to all of the symbol, string, and hash tables,
+ * in the system with pointers to all of the symbol, string, and hash tables,
* as well as all of the other good stuff in the binary.
*/
-
struct elf_resolve *_dl_loaded_modules = NULL;
/*
@@ -55,12 +54,9 @@
struct dyn_elf *_dl_handles = NULL;
-/*
- * This is the hash function that is used by the ELF linker to generate
- * the hash table that each executable and library is required to
- * have. We need it to decode the hash table.
- */
-
+/* This is the hash function that is used by the ELF linker to generate the
+ * hash table that each executable and library is required to have. We need
+ * it to decode the hash table. */
unsigned long _dl_elf_hash(const char *name)
{
unsigned long hash = 0;
@@ -75,9 +71,7 @@
return hash;
}
-/*
- * Check to see if a library has already been added to the hash chain.
- */
+/* Check to see if a library has already been added to the hash chain. */
struct elf_resolve *_dl_check_hashed_files(const char *libname)
{
struct elf_resolve *tpnt;
@@ -97,9 +91,8 @@
* We add the relevant info to the symbol chain, so that we can resolve all
* externals properly.
*/
-
-struct elf_resolve *_dl_add_elf_hash_table(const char *libname,
- char *loadaddr, unsigned long *dynamic_info, unsigned long dynamic_addr,
+struct elf_resolve *_dl_add_elf_hash_table(const char *libname,
+ char *loadaddr, unsigned long *dynamic_info, unsigned long dynamic_addr,
unsigned long dynamic_size)
{
unsigned long *hash_addr;
@@ -107,8 +100,7 @@
int i;
if (!_dl_loaded_modules) {
- tpnt = _dl_loaded_modules =
- (struct elf_resolve *) _dl_malloc(sizeof(struct elf_resolve));
+ tpnt = _dl_loaded_modules = (struct elf_resolve *) _dl_malloc(sizeof(struct elf_resolve));
_dl_memset(tpnt, 0, sizeof(struct elf_resolve));
} else {
tpnt = _dl_loaded_modules;
@@ -161,21 +153,18 @@
* This function resolves externals, and this is either called when we process
* relocations or when we call an entry in the PLT table for the first time.
*/
-
-char *_dl_find_hash(const char *name, struct dyn_elf *rpnt1,
+char *_dl_find_hash(const char *name, struct dyn_elf *rpnt1,
struct elf_resolve *f_tpnt, enum caller_type caller_type)
{
struct elf_resolve *tpnt;
int si;
- char *pnt;
int pass;
char *strtab;
Elf32_Sym *symtab;
unsigned long elf_hash_number, hn;
char *weak_result;
- struct elf_resolve *first_def;
struct dyn_elf *rpnt, first;
- char *data_result = 0; /* nakao */
+ const ElfW(Sym) *sym;
weak_result = 0;
elf_hash_number = _dl_elf_hash(name);
@@ -185,7 +174,7 @@
that any shared library data symbols referenced in the executable
will be seen at the same address by the executable, shared libraries
and dynamically loaded code. -Rob Ryan (robr at cmu.edu) */
- if (_dl_symbol_tables && !caller_type && rpnt1) {
+ if (_dl_symbol_tables && rpnt1) {
first = (*_dl_symbol_tables);
first.next = rpnt1;
rpnt1 = (&first);
@@ -222,24 +211,16 @@
if (pass != 0) {
if (rpnt1 == NULL)
break;
- if ((rpnt1->flags & RTLD_GLOBAL) == 0)
- continue;
+ //if ((rpnt1->flags & RTLD_GLOBAL) == 0)
+ //continue;
}
for (rpnt = (rpnt1 ? rpnt1 : _dl_symbol_tables); rpnt; rpnt = rpnt->next) {
tpnt = rpnt->dyn;
- /*
- * The idea here is that if we are using dlsym, we want to
- * first search the entire chain loaded from dlopen, and
- * return a result from that if we found anything. If this
- * fails, then we continue the search into the stuff loaded
- * when the image was activated. For normal lookups, we start
- * with rpnt == NULL, so we should never hit this.
- */
- if (tpnt->libtype == elf_executable && weak_result != 0) {
- break;
- }
+ /* Don't search the executable when resolving a copy reloc. */
+ if (tpnt->libtype == elf_executable && caller_type == copyrel)
+ continue;
/*
* Avoid calling .urem here.
@@ -247,81 +228,35 @@
do_rem(hn, elf_hash_number, tpnt->nbucket);
symtab = (Elf32_Sym *) (intptr_t) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr);
strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);
- /*
- * This crap is required because the first instance of a
- * symbol on the chain will be used for all symbol references.
- * Thus this instance must be resolved to an address that
- * contains the actual function,
- */
- first_def = NULL;
-
- for (si = tpnt->elf_buckets[hn]; si; si = tpnt->chains[si]) {
- pnt = strtab + symtab[si].st_name;
-
- if (_dl_strcmp(pnt, name) == 0 &&
- symtab[si].st_value != 0)
- {
- if ((ELF32_ST_TYPE(symtab[si].st_info) == STT_FUNC ||
- ELF32_ST_TYPE(symtab[si].st_info) == STT_NOTYPE ||
- ELF32_ST_TYPE(symtab[si].st_info) == STT_OBJECT) &&
- symtab[si].st_shndx != SHN_UNDEF) {
-
- /* Here we make sure that we find a module where the symbol is
- * actually defined.
- */
+ for (si = tpnt->elf_buckets[hn]; si != STN_UNDEF; si = tpnt->chains[si]) {
+ sym = &symtab[si];
- if (f_tpnt) {
- if (!first_def)
- first_def = tpnt;
- if (first_def == f_tpnt
- && symtab[si].st_shndx == 0)
- continue;
- }
+ if (sym->st_value == 0)
+ continue;
+ if (ELF32_ST_TYPE(sym->st_info) > STT_FUNC)
+ continue;
+ if (sym->st_shndx == SHN_UNDEF && caller_type != copyrel)
+ continue;
+ if (_dl_strcmp(strtab + sym->st_name, name) != 0)
+ continue;
- switch (ELF32_ST_BIND(symtab[si].st_info)) {
- case STB_GLOBAL:
- if (tpnt->libtype != elf_executable &&
- ELF32_ST_TYPE(symtab[si].st_info)
- == STT_NOTYPE)
- { /* nakao */
- data_result = (char *)tpnt->loadaddr +
- symtab[si].st_value; /* nakao */
- break; /* nakao */
- } else /* nakao */
- return (char*)tpnt->loadaddr + symtab[si].st_value;
- case STB_WEAK:
- if (!weak_result)
- weak_result = (char *)tpnt->loadaddr + symtab[si].st_value;
- break;
- default: /* Do local symbols need to be examined? */
- break;
- }
- }
-#ifndef __mips__
- /*
- * References to the address of a function from an executable file and
- * the shared objects associated with it might not resolve to the same
- * value. To allow comparisons of function addresses we must resolve
- * to the address of the plt entry of the executable instead of the
- * real function address.
- * see "TIS ELF Specification Version 1.2, Book 3, A-11 (Function
- * Adresses)
- */
- if (resolver != caller_type &&
- NULL==f_tpnt && /*trick: don't handle R_??_JMP_SLOT reloc type*/
- tpnt->libtype == elf_executable &&
- ELF32_ST_TYPE(symtab[si].st_info) == STT_FUNC &&
- symtab[si].st_shndx == SHN_UNDEF)
- {
- return (char*)symtab[si].st_value;
- }
+ switch (ELF32_ST_BIND(sym->st_info)) {
+ case STB_WEAK:
+//Disable this to match current glibc behavior. Of course,
+//this doesn't actually work yet and will cause segfaults...
+#if 1
+ if (!weak_result)
+ weak_result = (char *)tpnt->loadaddr + sym->st_value;
+ break;
#endif
+ case STB_GLOBAL:
+ return (char*)tpnt->loadaddr + sym->st_value;
+ default: /* Local symbols not handled here */
+ break;
}
}
}
}
- if (data_result)
- return data_result; /* nakao */
return weak_result;
}
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