/* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */
/* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */
/* Copyright (C) 2014 OSCAR lab, Stony Brook University
This file is part of Graphene Library OS.
Graphene Library OS is free software: you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
Graphene Library OS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see . */
/*
* db_rtld.c
*
* This file contains utilities to load ELF binaries into the memory
* and link them against each other.
* The source code in this file is imported and modified from the GNU C
* Library.
*/
#include "pal_defs.h"
#include "pal_freebsd_defs.h"
#include "pal.h"
#include "pal_internal.h"
#include "pal_freebsd.h"
#include "pal_debug.h"
#include "pal_error.h"
#include "pal_security.h"
#include "pal_rtld.h"
#include "api.h"
#include
#include
#include
#include "elf-x86_64.h"
/* This structure communicates dl state to the debugger. The debugger
normally finds it via the DT_DEBUG entry in the dynamic section, but in
a statically-linked program there is no dynamic section for the debugger
to examine and it looks for this particular symbol name. */
struct r_debug pal_r_debug =
{ 1, NULL, &pal_r_debug_state, RT_CONSISTENT, };
extern __typeof(pal_r_debug) r_debug
__attribute ((alias ("pal_r_debug")));
/* This function exists solely to have a breakpoint set on it by the
debugger. The debugger is supposed to find this function's address by
examining the r_brk member of struct r_debug, but GDB 4.15 in fact looks
for this particular symbol name in the PT_INTERP file. */
/* The special symbol name is set as breakpoint in gdb */
void __attribute__((noinline))
pal_r_debug_state (struct r_debug * rd, struct link_gdb_map * map)
{
if (pal_sec.r_debug_state)
pal_sec.r_debug_state(rd, map);
asm volatile ("" ::: "memory");
}
extern __typeof(pal_r_debug_state) r_debug_state
__attribute ((alias ("pal_r_debug_state")));
void _DkDebugAddMap (struct link_map * map)
{
struct r_debug * dbg = pal_sec.r_debug ? : &pal_r_debug;
int len = map->l_name ? strlen(map->l_name) + 1 : 0;
struct link_map ** prev = &dbg->r_map, * last = NULL,
* tmp = *prev;
while (tmp) {
if (tmp->l_addr == map->l_addr &&
tmp->l_ld == map->l_ld &&
!memcmp(tmp->l_name, map->l_name, len))
return;
last = tmp;
tmp = *(prev = &last->l_next);
}
struct link_gdb_map * m = malloc(sizeof(struct link_gdb_map) + len);
if (!m)
return;
if (len) {
m->l_name = (char *) m + sizeof(struct link_gdb_map);
memcpy((void *) m->l_name, map->l_name, len);
} else {
m->l_name = NULL;
}
m->l_addr = map->l_addr;
m->l_ld = map->l_real_ld;
dbg->r_state = RT_ADD;
pal_r_debug_state(dbg, m);
*prev = (struct link_map *) m;
m->l_prev = last;
m->l_next = NULL;
dbg->r_state = RT_CONSISTENT;
pal_r_debug_state(dbg, NULL);
}
void _DkDebugDelMap (struct link_map * map)
{
struct r_debug * dbg = pal_sec.r_debug ? : &pal_r_debug;
int len = map->l_name ? strlen(map->l_name) + 1 : 0;
struct link_gdb_map ** prev = (void *) &dbg->r_map;
struct link_gdb_map * last = NULL;
struct link_gdb_map * t = (void *) dbg->r_map, * m = NULL;
while (t) {
if (t->l_addr == map->l_addr &&
t->l_ld == map->l_ld &&
!memcmp(t->l_name, map->l_name, len)) {
m = t;
break;
}
last = t;
prev = (void *) last->l_next;
t = *prev;
}
if (!m)
return;
dbg->r_state = RT_DELETE;
pal_r_debug_state(dbg, m);
if (last)
last->l_next = m->l_next;
else
dbg->r_map = m->l_next;
if (m->l_next)
m->l_next->l_prev = (void *) last;
free(m);
dbg->r_state = RT_CONSISTENT;
pal_r_debug_state(dbg, NULL);
}
extern void setup_elf_hash (struct link_map *map);
void setup_pal_map (struct link_map * pal_map)
{
const ElfW(Ehdr) * header = (void *) pal_map->l_addr;
pal_map->l_real_ld = pal_map->l_ld = (void *) elf_machine_dynamic();
pal_map->l_type = OBJECT_RTLD;
pal_map->l_entry = header->e_entry;
pal_map->l_phdr = (void *) (pal_map->l_addr + header->e_phoff);
pal_map->l_phnum = header->e_phnum;
setup_elf_hash(pal_map);
_DkDebugAddMap(pal_map);
pal_map->l_prev = pal_map->l_next = NULL;
loaded_maps = pal_map;
}
ElfW(Addr) resolve_rtld (const char * sym_name)
{
/* We are not using this, because in Linux we can rely on
rtld_map to directly lookup symbols */
return 0;
}