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- /* -*- 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 <http://www.gnu.org/licenses/>. */
- /*
- * 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 <sysdeps/generic/ldsodefs.h>
- #include <elf/elf.h>
- #include <bits/dlfcn.h>
- #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;
- }
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