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/*
* This file is part of ltrace.
* Copyright (C) 2012 Petr Machata, Red Hat Inc.
* Copyright (C) 1998,2004,2008,2009 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 "config.h"
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <sys/ptrace.h>
#include <asm/ptrace.h>
#include "proc.h"
#include "common.h"
#include "output.h"
#include "ptrace.h"
#if (!defined(PTRACE_PEEKUSER) && defined(PTRACE_PEEKUSR))
# define PTRACE_PEEKUSER PTRACE_PEEKUSR
#endif
#if (!defined(PTRACE_POKEUSER) && defined(PTRACE_POKEUSR))
# define PTRACE_POKEUSER PTRACE_POKEUSR
#endif
#define off_r0 ((void *)0)
#define off_r7 ((void *)28)
#define off_ip ((void *)48)
#define off_pc ((void *)60)
void
get_arch_dep(Process *proc) {
proc_archdep *a;
if (!proc->arch_ptr)
proc->arch_ptr = (void *)malloc(sizeof(proc_archdep));
a = (proc_archdep *) (proc->arch_ptr);
a->valid = (ptrace(PTRACE_GETREGS, proc->pid, 0, &a->regs) >= 0);
}
/* Returns 0 if not a syscall,
* 1 if syscall entry, 2 if syscall exit,
* 3 if arch-specific syscall entry, 4 if arch-specific syscall exit,
* -1 on error.
*/
int
syscall_p(Process *proc, int status, int *sysnum) {
if (WIFSTOPPED(status)
&& WSTOPSIG(status) == (SIGTRAP | proc->tracesysgood)) {
/* get the user's pc (plus 8) */
unsigned pc = ptrace(PTRACE_PEEKUSER, proc->pid, off_pc, 0);
pc = pc - 4;
/* fetch the SWI instruction */
unsigned insn = ptrace(PTRACE_PEEKTEXT, proc->pid,
(void *)pc, 0);
int ip = ptrace(PTRACE_PEEKUSER, proc->pid, off_ip, 0);
if (insn == 0xef000000 || insn == 0x0f000000
|| (insn & 0xffff0000) == 0xdf000000) {
/* EABI syscall */
*sysnum = ptrace(PTRACE_PEEKUSER, proc->pid, off_r7, 0);
} else if ((insn & 0xfff00000) == 0xef900000) {
/* old ABI syscall */
*sysnum = insn & 0xfffff;
} else {
/* TODO: handle swi<cond> variations */
/* one possible reason for getting in here is that we
* are coming from a signal handler, so the current
* PC does not point to the instruction just after the
* "swi" one. */
output_line(proc, "unexpected instruction 0x%x at %p",
insn, pc);
return 0;
}
if ((*sysnum & 0xf0000) == 0xf0000) {
/* arch-specific syscall */
*sysnum &= ~0xf0000;
return ip ? 4 : 3;
}
/* ARM syscall convention: on syscall entry, ip is zero;
* on syscall exit, ip is non-zero */
return ip ? 2 : 1;
}
return 0;
}
long
gimme_arg(enum tof type, Process *proc, int arg_num, struct arg_type_info *info)
{
proc_archdep *a = (proc_archdep *) proc->arch_ptr;
if (arg_num == -1) { /* return value */
return ptrace(PTRACE_PEEKUSER, proc->pid, off_r0, 0);
}
/* deal with the ARM calling conventions */
if (type == LT_TOF_FUNCTION || type == LT_TOF_FUNCTIONR) {
if (arg_num < 4) {
if (a->valid && type == LT_TOF_FUNCTION)
return a->regs.uregs[arg_num];
if (a->valid && type == LT_TOF_FUNCTIONR)
return a->func_arg[arg_num];
return ptrace(PTRACE_PEEKUSER, proc->pid,
(void *)(4 * arg_num), 0);
} else {
return ptrace(PTRACE_PEEKDATA, proc->pid,
proc->stack_pointer + 4 * (arg_num - 4),
0);
}
} else if (type == LT_TOF_SYSCALL || type == LT_TOF_SYSCALLR) {
if (arg_num < 5) {
if (a->valid && type == LT_TOF_SYSCALL)
return a->regs.uregs[arg_num];
if (a->valid && type == LT_TOF_SYSCALLR)
return a->sysc_arg[arg_num];
return ptrace(PTRACE_PEEKUSER, proc->pid,
(void *)(4 * arg_num), 0);
} else {
return ptrace(PTRACE_PEEKDATA, proc->pid,
proc->stack_pointer + 4 * (arg_num - 5),
0);
}
} else {
fprintf(stderr, "gimme_arg called with wrong arguments\n");
exit(1);
}
return 0;
}
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