a [mostly working] elfinterp.c based on i386 / glibc

1 files changed, 324 insertions, 0 deletions

diff --git a/ldso/ldso/x86_64/elfinterp.c b/ldso/ldso/x86_64/elfinterp.c
new file mode 100644
index 000000000..66552d879
--- /dev/null
+++ b/ldso/ldso/x86_64/elfinterp.c
@@ -0,0 +1,324 @@
+/* vi: set sw=4 ts=4: */
+/* x86_64 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)
+{
+	int reloc_type;
+	ELF_RELOC *this_reloc;
+	char *strtab;
+	ElfW(Sym) *symtab;
+	int symtab_index;
+	char *rel_addr;
+	char *new_addr;
+	char **got_addr;
+	ElfW(Addr) instr_addr;
+	char *symname;
+
+	rel_addr = (char *)tpnt->dynamic_info[DT_JMPREL];
+	this_reloc = (ELF_RELOC *)(rel_addr + reloc_entry);
+	reloc_type = ELF_R_TYPE(this_reloc->r_info);
+	symtab_index = ELF_R_SYM(this_reloc->r_info);
+
+	symtab = (ElfW(Sym) *)tpnt->dynamic_info[DT_SYMTAB];
+	strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
+	symname = strtab + symtab[symtab_index].st_name;
+
+	if (unlikely(reloc_type != R_X86_64_JUMP_SLOT)) {
+		_dl_dprintf(2, "%s: Incorrect relocation type in jump relocations\n",
+		            _dl_progname);
+		_dl_exit(1);
+	}
+
+	/* Address of the jump instruction to fix up. */
+	instr_addr = (this_reloc->r_offset + tpnt->loadaddr);
+	got_addr = (char **)instr_addr;
+
+	/* Get the address of the GOT entry. */
+	new_addr = _dl_find_hash(symname, tpnt->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT);
+	if (unlikely(!new_addr)) {
+		_dl_dprintf(2, "%s: Can't resolve symbol '%s'\n", _dl_progname, symname);
+		_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,
+				            "\tpatched: %x ==> %x @ %x\n",
+				            *got_addr, new_addr, got_addr);
+		}
+	}
+	if (!_dl_debug_nofixups)
+#endif
+		*got_addr = new_addr;
+
+	return (unsigned long)new_addr;
+}
+
+static int
+_dl_parse(struct elf_resolve *tpnt, struct dyn_elf *scope,
+	  unsigned long rel_addr, unsigned long rel_size,
+	  int (*reloc_fnc)(struct elf_resolve *tpnt, struct dyn_elf *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 *)rel_addr;
+	rel_size /= sizeof(ELF_RELOC);
+
+	symtab = (ElfW(Sym) *)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);
+
+			_dl_dprintf(2, "can't handle reloc type "
+#if defined (__SUPPORT_LD_DEBUG__)
+				    "%s\n", _dl_reltypes(reloc_type));
+#else
+				    "%x\n", reloc_type);
+#endif
+			_dl_exit(-res);
+		} else if (unlikely(res > 0)) {
+			_dl_dprintf(2, "can't resolve symbol\n");
+			return res;
+		}
+	}
+
+	return 0;
+}
+
+static int
+_dl_do_reloc(struct elf_resolve *tpnt, struct dyn_elf *scope,
+	     ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
+{
+	int reloc_type;
+	int symtab_index;
+	char *symname;
+	ElfW(Addr) *reloc_addr;
+	ElfW(Addr) symbol_addr;
+#if defined (__SUPPORT_LD_DEBUG__)
+	ElfW(Addr) old_val;
+#endif
+
+	reloc_addr = (ElfW(Addr)*)(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;
+	symname = strtab + symtab[symtab_index].st_name;
+
+	if (symtab_index) {
+		symbol_addr = (ElfW(Addr))_dl_find_hash(symname, scope, tpnt,
+							    elf_machine_type_class(reloc_type));
+		/*
+		 * 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_BIND(symtab[symtab_index].st_info) != STB_WEAK)) {
+			_dl_dprintf(2, "%s: can't resolve symbol '%s'\n", _dl_progname, symname);
+			_dl_exit(1);
+		};
+	}
+
+#if defined (__SUPPORT_LD_DEBUG__)
+	old_val = *reloc_addr;
+#endif
+
+	switch (reloc_type) {
+		case R_X86_64_NONE:
+			break;
+
+		case R_X86_64_64:
+			*reloc_addr = symbol_addr + rpnt->r_addend;
+			break;
+
+		case R_X86_64_PC32:
+			*reloc_addr = symbol_addr + rpnt->r_addend - rpnt->r_offset;
+			break;
+
+		case R_X86_64_GLOB_DAT:
+		case R_X86_64_JUMP_SLOT:
+			*reloc_addr = symbol_addr;
+			break;
+
+		/* handled by elf_machine_relative()
+		case R_X86_64_RELATIVE:
+			*reloc_addr = map->l_addr + rpnt->r_addend;
+			break;
+		*/
+#if 0
+		case R_X86_64_DTPMOD64:
+			break;
+		case R_X86_64_DTPOFF64:
+			*reloc_addr = symbol_addr + rpnt->r_addend;
+			break;
+		case R_X86_64_TPOFF64:
+			*reloc_addr = symbol_addr + rpnt->r_addend;
+			break;
+		case R_X86_64_32:
+			*reloc_addr = symbol_addr + rpnt->r_addend;
+			break;
+
+#endif
+		case R_X86_64_COPY:
+			if (symbol_addr) {
+#if defined (__SUPPORT_LD_DEBUG__)
+				if (_dl_debug_move)
+					_dl_dprintf(_dl_debug_file,
+						    "\t%s move %d bytes from %x to %x\n",
+						    symname, symtab[symtab_index].st_size,
+						    symbol_addr, reloc_addr);
+#endif
+
+				_dl_memcpy((char *)reloc_addr,
+					   (char *)symbol_addr,
+					   symtab[symtab_index].st_size);
+			} else
+				_dl_dprintf(_dl_debug_file, "no symbol_addr to copy !?\n");
+			break;
+
+		default:
+			return -1;	/* Calls _dl_exit(1). */
+	}
+
+#if defined (__SUPPORT_LD_DEBUG__)
+	if (_dl_debug_reloc && _dl_debug_detail)
+		_dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x\n",
+			    old_val, *reloc_addr, reloc_addr);
+#endif
+
+	return 0;
+}
+
+#if 0
+static int
+_dl_do_lazy_reloc(struct elf_resolve *tpnt, struct dyn_elf *scope,
+		  ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
+{
+	int reloc_type;
+	int symtab_index;
+	ElfW(Addr) *reloc_addr;
+#if defined (__SUPPORT_LD_DEBUG__)
+	ElfW(Addr) old_val;
+#endif
+
+	(void)scope;
+	symtab_index = ELF_R_SYM(rpnt->r_info);
+	(void)strtab;
+
+	reloc_addr = (ElfW(Addr)*)(tpnt->loadaddr + 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_X86_64_NONE:
+			break;
+		case R_X86_64_JUMP_SLOT:
+			*reloc_addr = tpnt->loadaddr + symtab[symtab_index].st_value;
+			break;
+		default:
+			_dl_exit(1);
+	}
+
+#if defined (__SUPPORT_LD_DEBUG__)
+	if (_dl_debug_reloc && _dl_debug_detail)
+		_dl_dprintf(_dl_debug_file, "\tpatched_lazy: %x ==> %x @ %x\n",
+			    old_val, *reloc_addr, reloc_addr);
+#endif
+
+	return 0;
+}
+#endif
+
+void
+_dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
+				      unsigned long rel_addr,
+				      unsigned long rel_size)
+{
+	_dl_parse_relocation_information(rpnt, rel_addr, rel_size);
+/*	jump slot isnt working
+	(void)_dl_parse(rpnt->dyn, NULL, rel_addr, rel_size, _dl_do_lazy_reloc);
+*/
+}
+
+int
+_dl_parse_relocation_information(struct dyn_elf *rpnt,
+				 unsigned long rel_addr,
+				 unsigned long rel_size)
+{
+	return _dl_parse(rpnt->dyn, rpnt->dyn->symbol_scope, rel_addr, rel_size, _dl_do_reloc);
+}