Don't use the symbol name to lookup the symbol value when we can use

the symbol index defined by the relocation. The elf_lookup() support
function is to be used by elf_reloc() when symbol lookups need to be
done. The elf_lookup() function operates on the symbol index and
will do a symbol name based lookup when such is required, otherwise
it uses the symbol index directly. This solves the problem seen on
ia64 where the symbol hash table does not contain local symbols and
a symbol name based lookup would fail for those symbols.

Don't pass the symbol name to elf_reloc(), as it isn't used any more.

1 files changed, 55 insertions, 8 deletions

diff --git a/sys/kern/link_elf_obj.c b/sys/kern/link_elf_obj.c
index 8eb7681..dd59405 100644
--- a/sys/kern/link_elf_obj.c
+++ b/sys/kern/link_elf_obj.c
@@ -904,8 +904,8 @@ relocate_file(elf_file_t ef)
     if (rel) {
 	rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize);
 	while (rel < rellim) {
-	    symname = symbol_name(ef, rel->r_info);
-	    if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) {
+	    if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL)) {
+		symname = symbol_name(ef, rel->r_info);
 		printf("link_elf: symbol %s undefined\n", symname);
 		return ENOENT;
 	    }
@@ -918,8 +918,8 @@ relocate_file(elf_file_t ef)
     if (rela) {
 	relalim = (const Elf_Rela *)((const char *)ef->rela + ef->relasize);
 	while (rela < relalim) {
-	    symname = symbol_name(ef, rela->r_info);
-	    if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) {
+	    if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA)) {
+		symname = symbol_name(ef, rela->r_info);
 		printf("link_elf: symbol %s undefined\n", symname);
 		return ENOENT;
 	    }
@@ -932,8 +932,8 @@ relocate_file(elf_file_t ef)
     if (rel) {
 	rellim = (const Elf_Rel *)((const char *)ef->pltrel + ef->pltrelsize);
 	while (rel < rellim) {
-	    symname = symbol_name(ef, rel->r_info);
-	    if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL, symname)) {
+	    if (elf_reloc(&ef->lf, rel, ELF_RELOC_REL)) {
+		symname = symbol_name(ef, rel->r_info);
 		printf("link_elf: symbol %s undefined\n", symname);
 		return ENOENT;
 	    }
@@ -946,8 +946,8 @@ relocate_file(elf_file_t ef)
     if (rela) {
 	relalim = (const Elf_Rela *)((const char *)ef->pltrela + ef->pltrelasize);
 	while (rela < relalim) {
-	    symname = symbol_name(ef, rela->r_info);
-	    if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA, symname)) {
+	    if (elf_reloc(&ef->lf, rela, ELF_RELOC_RELA)) {
+		symname = symbol_name(ef, rela->r_info);
 		printf("link_elf: symbol %s undefined\n", symname);
 		return ENOENT;
 	    }
@@ -1190,3 +1190,50 @@ link_elf_get_gp(linker_file_t lf)
 	return (Elf_Addr)ef->got;
 }
 #endif
+
+/*
+ * Symbol lookup function that can be used when the symbol index is known (ie
+ * in relocations). It uses the symbol index instead of doing a fully fledged
+ * hash table based lookup when such is valid. For example for local symbols.
+ * This is not only more efficient, it's also more correct. It's not always
+ * the case that the symbol can be found through the hash table.
+ */
+Elf_Addr
+elf_lookup(linker_file_t lf, Elf_Word symidx, int deps)
+{
+	elf_file_t ef = (elf_file_t)lf;
+	const Elf_Sym *sym;
+	const char *symbol;
+
+	/* Don't even try to lookup the symbol if the index is bogus. */
+	if (symidx >= ef->nchains)
+		return (0);
+
+	sym = ef->symtab + symidx;
+
+	/*
+	 * Don't do a full lookup when the symbol is local. It may even
+	 * fail because it may not be found through the hash table.
+	 */
+	if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
+		/* Force lookup failure when we have an insanity. */
+		if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0)
+			return (0);
+		return ((Elf_Addr)ef->address + sym->st_value);
+	}
+
+	/*
+	 * XXX we can avoid doing a hash table based lookup for global
+	 * symbols as well. This however is not always valid, so we'll
+	 * just do it the hard way for now. Performance tweaks can
+	 * always be added.
+	 */
+
+	symbol = ef->strtab + sym->st_name;
+
+	/* Force a lookup failure if the symbol name is bogus. */
+	if (*symbol == 0)
+		return (0);
+
+	return ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps));
+}