trace.c revision e99af270a60891e68d465c4cd97dbe29cd1a05e4 
1/*
2 * This file is part of ltrace.
3 * Copyright (C) 2010 Edgar E. Iglesias
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation; either version 2 of the
8 * License, or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
18 * 02110-1301 USA
19 */
20
21#if HAVE_CONFIG_H
22#include "config.h"
23#endif
24
25#include <sys/types.h>
26#include <sys/wait.h>
27#include <signal.h>
28#include <sys/ptrace.h>
29#include <asm/ptrace.h>
30#include <elf.h>
31
32#include "proc.h"
33#include "common.h"
34
35#if (!defined(PTRACE_PEEKUSER) && defined(PTRACE_PEEKUSR))
36# define PTRACE_PEEKUSER PTRACE_PEEKUSR
37#endif
38
39#if (!defined(PTRACE_POKEUSER) && defined(PTRACE_POKEUSR))
40# define PTRACE_POKEUSER PTRACE_POKEUSR
41#endif
42
43void get_arch_dep(Process *proc)
44{
45}
46
47/* Returns 1 if syscall, 2 if sysret, 0 otherwise.
48 */
49#define SYSCALL_INSN   0xe93d
50int syscall_p(Process *proc, int status, int *sysnum)
51{
52	if (WIFSTOPPED(status)
53	    && WSTOPSIG(status) == (SIGTRAP | proc->tracesysgood)) {
54		long pc = (long)get_instruction_pointer(proc);
55		unsigned int insn =
56		    (int)ptrace(PTRACE_PEEKTEXT, proc->pid, pc - sizeof(long),
57				0);
58
59		if ((insn >> 16) == SYSCALL_INSN) {
60			*sysnum =
61			    (int)ptrace(PTRACE_PEEKUSER, proc->pid,
62					sizeof(long) * PT_R9, 0);
63			if (proc->callstack_depth > 0
64			    && proc->callstack[proc->callstack_depth -
65					       1].is_syscall) {
66				return 2;
67			}
68			return 1;
69		}
70	}
71	return 0;
72}
73
74long gimme_arg(enum tof type, Process *proc, int arg_num,
75	       struct arg_type_info *info)
76{
77	int pid = proc->pid;
78
79	if (arg_num == -1) {	/* return value */
80		return ptrace(PTRACE_PEEKUSER, pid, PT_R10 * 4, 0);
81	} else if (arg_num < 6) {
82		int pt_arg[6] =
83			{
84				PT_ORIG_R10, PT_R11, PT_R12, PT_R13, PT_MOF,
85				PT_SRP
86			};
87		return ptrace(PTRACE_PEEKUSER, pid, pt_arg[arg_num] * 4, 0);
88	} else {
89		return ptrace(PTRACE_PEEKDATA, pid,
90			      proc->stack_pointer + 4 * (arg_num - 6), 0);
91	}
92	return 0;
93}
94