--- /dev/null
+/* vi: set sw=4 ts=4: */
+/* i386 ELF shared library loader suppport
+ *
+ * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
+ * David Engel, Hongjiu Lu and Mitch D'Souza
+ * Copyright (C) 2001-2004 Erik Andersen
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. The name of the above contributors may not be
+ * used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "ldso.h"
+
+/* Program to load an ELF binary on a linux system, and run it.
+ References to symbols in sharable libraries can be resolved by either
+ an ELF sharable library or a linux style of shared library. */
+
+/* Disclaimer: I have never seen any AT&T source code for SVr4, nor have
+ I ever taken any courses on internals. This program was developed using
+ information available through the book "UNIX SYSTEM V RELEASE 4,
+ Programmers guide: Ansi C and Programming Support Tools", which did
+ a more than adequate job of explaining everything required to get this
+ working. */
+
+extern int _dl_linux_resolve(void);
+
+unsigned long
+_dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)
+{
+ ELF_RELOC *this_reloc;
+ char *strtab;
+ ElfW(Sym) *symtab;
+ int symtab_index;
+ char *rel_addr;
+ char *new_addr;
+ char **got_addr;
+ unsigned long instr_addr;
+ char *symname;
+
+ rel_addr = (char *)tpnt->dynamic_info[DT_JMPREL];
+ this_reloc = (ELF_RELOC *)(intptr_t)(rel_addr + reloc_entry);
+ symtab_index = ELF_R_SYM(this_reloc->r_info);
+
+ symtab = (ElfW(Sym) *)(intptr_t)tpnt->dynamic_info[DT_SYMTAB];
+ strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
+ symname = strtab + symtab[symtab_index].st_name;
+
+ /* Address of the jump instruction to fix up. */
+ instr_addr = ((unsigned long)this_reloc->r_offset +
+ (unsigned long)tpnt->loadaddr);
+ got_addr = (char **)instr_addr;
+
+ /* Get the address of the GOT entry. */
+ new_addr = _dl_find_hash(symname, &_dl_loaded_modules->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT, NULL);
+ if (unlikely(!new_addr)) {
+ _dl_dprintf(2, "%s: can't resolve symbol '%s' in lib '%s'.\n", _dl_progname, symname, tpnt->libname);
+ _dl_exit(1);
+ }
+
+#if defined (__SUPPORT_LD_DEBUG__)
+ if ((unsigned long)got_addr < 0x40000000) {
+ if (_dl_debug_bindings) {
+ _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);
+ if (_dl_debug_detail)
+ _dl_dprintf(_dl_debug_file,
+ "\n\tpatched: %x ==> %x @ %x",
+ *got_addr, new_addr, got_addr);
+ }
+ }
+ if (!_dl_debug_nofixups) {
+ *got_addr = new_addr;
+ }
+#else
+ *got_addr = new_addr;
+#endif
+
+ return (unsigned long)new_addr;
+}
+
+static int
+_dl_parse(struct elf_resolve *tpnt, struct r_scope_elem *scope,
+ unsigned long rel_addr, unsigned long rel_size,
+ int (*reloc_fnc)(struct elf_resolve *tpnt, struct r_scope_elem *scope,
+ ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab))
+{
+ unsigned int i;
+ char *strtab;
+ ElfW(Sym) *symtab;
+ ELF_RELOC *rpnt;
+ int symtab_index;
+
+ /* Parse the relocation information. */
+ rpnt = (ELF_RELOC *)(intptr_t)rel_addr;
+ rel_size /= sizeof(ELF_RELOC);
+
+ symtab = (ElfW(Sym) *)(intptr_t)tpnt->dynamic_info[DT_SYMTAB];
+ strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
+
+ for (i = 0; i < rel_size; i++, rpnt++) {
+ int res;
+
+ symtab_index = ELF_R_SYM(rpnt->r_info);
+
+ debug_sym(symtab, strtab, symtab_index);
+ debug_reloc(symtab, strtab, rpnt);
+
+ res = reloc_fnc(tpnt, scope, rpnt, symtab, strtab);
+
+ if (res == 0)
+ continue;
+
+ _dl_dprintf(2, "\n%s: ", _dl_progname);
+
+ if (symtab_index)
+ _dl_dprintf(2, "symbol '%s': ",
+ strtab + symtab[symtab_index].st_name);
+
+ if (unlikely(res < 0)) {
+ int reloc_type = ELF_R_TYPE(rpnt->r_info);
+
+#if defined (__SUPPORT_LD_DEBUG__)
+ _dl_dprintf(2, "can't handle reloc type '%s' in lib '%s'\n",
+ _dl_reltypes(reloc_type), tpnt->libname);
+#else
+ _dl_dprintf(2, "can't handle reloc type %x in lib '%s'\n",
+ reloc_type, tpnt->libname);
+#endif
+ return res;
+ } else if (unlikely(res > 0)) {
+ _dl_dprintf(2, "can't resolve symbol in lib '%s'.\n", tpnt->libname);
+ return res;
+ }
+ }
+
+ return 0;
+}
+
+static int
+_dl_do_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
+ ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
+{
+ int reloc_type;
+ int symtab_index;
+ char *symname;
+ struct elf_resolve *tls_tpnt = NULL;
+ unsigned long *reloc_addr;
+ unsigned long symbol_addr;
+#if defined (__SUPPORT_LD_DEBUG__)
+ unsigned long old_val;
+#endif
+ struct symbol_ref sym_ref;
+
+ reloc_addr = (unsigned long *)(intptr_t)(tpnt->loadaddr + (unsigned long)rpnt->r_offset);
+ reloc_type = ELF_R_TYPE(rpnt->r_info);
+ symtab_index = ELF_R_SYM(rpnt->r_info);
+ symbol_addr = 0;
+ sym_ref.sym = &symtab[symtab_index];
+ sym_ref.tpnt = NULL;
+ symname = strtab + symtab[symtab_index].st_name;
+
+ if (symtab_index) {
+ symbol_addr = (unsigned long)_dl_find_hash(symname, scope, tpnt,
+ elf_machine_type_class(reloc_type), &sym_ref);
+
+ /*
+ * We want to allow undefined references to weak symbols - this
+ * might have been intentional. We should not be linking local
+ * symbols here, so all bases should be covered.
+ */
+ if (unlikely(!symbol_addr && (ELF_ST_TYPE(symtab[symtab_index].st_info) != STT_TLS)
+ && ELF_ST_BIND(symtab[symtab_index].st_info) != STB_WEAK))
+ return 1;
+ if (_dl_trace_prelink) {
+ _dl_debug_lookup (symname, tpnt, &symtab[symtab_index],
+ &sym_ref, elf_machine_type_class(reloc_type));
+ }
+ tls_tpnt = sym_ref.tpnt;
+ } else {
+ symbol_addr = symtab[symtab_index].st_value;
+ tls_tpnt = tpnt;
+ }
+
+#if defined (__SUPPORT_LD_DEBUG__)
+ /* Start: aw11: fixed pagefault with empty relocations */
+ if (reloc_type != R_386_NONE) old_val = *reloc_addr; else old_val = 0;
+ /* End: aw11 */
+#endif
+
+ switch (reloc_type) {
+ case R_386_NONE:
+ break;
+ case R_386_32:
+ *reloc_addr += symbol_addr;
+ break;
+ case R_386_PC32:
+ *reloc_addr += symbol_addr - (unsigned long)reloc_addr;
+ break;
+ case R_386_GLOB_DAT:
+ case R_386_JMP_SLOT:
+ *reloc_addr = symbol_addr;
+ break;
+ case R_386_RELATIVE:
+ *reloc_addr += (unsigned long)tpnt->loadaddr;
+ break;
+ case R_386_COPY:
+ if (symbol_addr) {
+#if defined (__SUPPORT_LD_DEBUG__)
+ if (_dl_debug_move)
+ _dl_dprintf(_dl_debug_file,
+ "\n%s move %d bytes from %x to %x",
+ symname, symtab[symtab_index].st_size,
+ symbol_addr, reloc_addr);
+#endif
+
+ _dl_memcpy((char *)reloc_addr,
+ (char *)symbol_addr,
+ symtab[symtab_index].st_size);
+ }
+ break;
+#if defined USE_TLS && USE_TLS
+ case R_386_TLS_DTPMOD32:
+ *reloc_addr = tls_tpnt->l_tls_modid;
+ break;
+ case R_386_TLS_DTPOFF32:
+ /* During relocation all TLS symbols are defined and used.
+ * Therefore the offset is already correct. */
+ *reloc_addr = symbol_addr;
+ break;
+ case R_386_TLS_TPOFF32:
+ /* The offset is positive, backward from the thread pointer. */
+ CHECK_STATIC_TLS((struct link_map*) tls_tpnt);
+ *reloc_addr += tls_tpnt->l_tls_offset - symbol_addr;
+ break;
+ case R_386_TLS_TPOFF:
+ /* The offset is negative, forward from the thread pointer. */
+ CHECK_STATIC_TLS((struct link_map*) tls_tpnt);
+ *reloc_addr += symbol_addr - tls_tpnt->l_tls_offset;
+ break;
+#endif
+ default:
+ return -1;
+ }
+
+#if defined (__SUPPORT_LD_DEBUG__)
+ if (_dl_debug_reloc && _dl_debug_detail)
+ _dl_dprintf(_dl_debug_file, "\n\tpatched: %x ==> %x @ %x\n",
+ old_val, *reloc_addr, reloc_addr);
+#endif
+
+ return 0;
+}
+
+static int
+_dl_do_lazy_reloc(struct elf_resolve *tpnt, struct r_scope_elem *scope,
+ ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
+{
+ int reloc_type;
+ unsigned long *reloc_addr;
+#if defined (__SUPPORT_LD_DEBUG__)
+ unsigned long old_val;
+#endif
+
+ (void)scope;
+ (void)symtab;
+ (void)strtab;
+
+ reloc_addr = (unsigned long *)(intptr_t)(tpnt->loadaddr + (unsigned long)rpnt->r_offset);
+ reloc_type = ELF_R_TYPE(rpnt->r_info);
+
+#if defined (__SUPPORT_LD_DEBUG__)
+ old_val = *reloc_addr;
+#endif
+
+ switch (reloc_type) {
+ case R_386_NONE:
+ break;
+ case R_386_JMP_SLOT:
+ *reloc_addr += (unsigned long)tpnt->loadaddr;
+ break;
+ default:
+ return -1;
+ }
+
+#if defined (__SUPPORT_LD_DEBUG__)
+ if (_dl_debug_reloc && _dl_debug_detail)
+ _dl_dprintf(_dl_debug_file, "\n\tpatched: %x ==> %x @ %x\n",
+ old_val, *reloc_addr, reloc_addr);
+#endif
+
+ return 0;
+}
+
+void
+_dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
+ unsigned long rel_addr,
+ unsigned long rel_size)
+{
+ (void)_dl_parse(rpnt->dyn, NULL, rel_addr, rel_size, _dl_do_lazy_reloc);
+}
+
+int
+_dl_parse_relocation_information(struct dyn_elf *rpnt,
+ struct r_scope_elem *scope,
+ unsigned long rel_addr,
+ unsigned long rel_size)
+{
+ return _dl_parse(rpnt->dyn, scope, rel_addr, rel_size, _dl_do_reloc);
+}