trace.c revision e99af270a60891e68d465c4cd97dbe29cd1a05e4 
1/*
2 * This file is part of ltrace.
3 * Copyright (C) 2004,2008,2009 Juan Cespedes
4 * Copyright (C) 2006 Ian Wienand
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation; either version 2 of the
9 * License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19 * 02110-1301 USA
20 */
21
22#include "config.h"
23
24#include <stdlib.h>
25#include <sys/types.h>
26#include <sys/wait.h>
27#include <signal.h>
28#include <string.h>
29#include "ptrace.h"
30#include "proc.h"
31#include "common.h"
32
33void
34get_arch_dep(Process *proc) {
35	proc_archdep *a;
36	if (!proc->arch_ptr)
37		proc->arch_ptr = (void *)malloc(sizeof(proc_archdep));
38	a = (proc_archdep *) (proc->arch_ptr);
39	a->valid = (ptrace(PTRACE_GETREGS, proc->pid, &a->regs, 0) >= 0);
40}
41
42/* Returns syscall number if `pid' stopped because of a syscall.
43 * Returns -1 otherwise
44 */
45int
46syscall_p(Process *proc, int status, int *sysnum) {
47	if (WIFSTOPPED(status)
48	    && WSTOPSIG(status) == (SIGTRAP | proc->tracesysgood)) {
49		void *ip = get_instruction_pointer(proc);
50		unsigned int insn;
51		if (ip == (void *)-1)
52			return 0;
53		insn = ptrace(PTRACE_PEEKTEXT, proc->pid, ip, 0);
54		if ((insn & 0xc1f8007f) == 0x81d00010) {
55			*sysnum = ((proc_archdep *) proc->arch_ptr)->regs.u_regs[UREG_G0];
56			if (proc->callstack_depth > 0 &&
57					proc->callstack[proc->callstack_depth - 1].is_syscall &&
58					proc->callstack[proc->callstack_depth - 1].c_un.syscall == *sysnum) {
59				return 2;
60			} else if (*sysnum >= 0) {
61				return 1;
62			}
63		}
64	}
65	return 0;
66}
67
68long
69gimme_arg(enum tof type, Process *proc, int arg_num, struct arg_type_info *info)
70{
71	proc_archdep *a = (proc_archdep *) proc->arch_ptr;
72	if (!a->valid) {
73		fprintf(stderr, "Could not get child registers\n");
74		exit(1);
75	}
76	if (arg_num == -1)	/* return value */
77		return a->regs.u_regs[UREG_G7];
78
79	if (type == LT_TOF_FUNCTION || type == LT_TOF_SYSCALL || arg_num >= 6) {
80		if (arg_num < 6)
81			return ((int *)&a->regs.u_regs[UREG_G7])[arg_num];
82		return ptrace(PTRACE_PEEKTEXT, proc->pid,
83			      proc->stack_pointer + 64 * (arg_num + 1));
84	} else if (type == LT_TOF_FUNCTIONR)
85		return a->func_arg[arg_num];
86	else if (type == LT_TOF_SYSCALLR)
87		return a->sysc_arg[arg_num];
88	else {
89		fprintf(stderr, "gimme_arg called with wrong arguments\n");
90		exit(1);
91	}
92	return 0;
93}
94