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/*
* This file is part of ltrace.
* Copyright (C) 2012 Petr Machata, Red Hat Inc.
* Copyright (C) 2008,2009 Juan Cespedes
* Copyright (C) 2006 Ian Wienand
*
* This program 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 2 of the
* License, or (at your option) any later version.
*
* This program 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, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include <errno.h>
#include <gelf.h>
#include <stdio.h>
#include <string.h>
#include <sys/ptrace.h>
#include "proc.h"
#include "common.h"
#include "library.h"
/* A bundle is 128 bits. */
#define BUNDLE_SIZE 16
/* The PLT has
*
* - 3 bundles as a header
*
* - The special reserved entry
*
* - Following that, each PLT entry has it's initial code that the GOT
* entry points to. Each PLT entry has one bundle allocated.
*
* - Following that, each PLT entry has two bundles of actual PLT
* code, i.e. load up the address from the GOT and jump to it. This
* is the point we want to insert the breakpoint, as this will be
* captured every time we jump to the PLT entry in the code.
*/
GElf_Addr
arch_plt_sym_val(struct ltelf *lte, size_t ndx, GElf_Rela * rela)
{
/* Find number of entires by removing header and special
* entry, dividing total size by three, since each PLT entry
* will have 3 bundles (1 for inital entry and two for the PLT
* code). */
int entries = (lte->plt_size - 4 * BUNDLE_SIZE) / (3 * BUNDLE_SIZE);
/* Now the point we want to break on is the PLT entry after
* all the header stuff */
unsigned long addr =
lte->plt_addr + (4 * BUNDLE_SIZE) + (BUNDLE_SIZE * entries) +
(2 * ndx * BUNDLE_SIZE);
debug(3, "Found PLT %zd entry at %lx", ndx, addr);
return addr;
}
void *
sym2addr(struct process *proc, struct library_symbol *sym)
{
return sym->enter_addr;
}
int
arch_translate_address_dyn(struct process *proc,
arch_addr_t addr, arch_addr_t *ret)
{
errno = 0;
unsigned long l = ptrace(PTRACE_PEEKTEXT, proc->pid, addr, 0);
if (l == -1UL && errno) {
fprintf(stderr, "dynamic .opd translation of %p: %s\n",
addr, strerror(errno));
return -1;
}
/* XXX The double cast should be removed when
* arch_addr_t becomes integral type. */
*ret = (arch_addr_t)(uintptr_t)l;
return 0;
}
int
arch_translate_address(struct ltelf *lte,
arch_addr_t addr, arch_addr_t *ret)
{
*ret = addr;
return 0;
}
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