breakpoint.c revision 2b46cfc1127d390eddd9593fe5ce5399c1f68130 
1/*
2 * This file is part of ltrace.
3 *
4 * Copyright (C) 2007 by Instituto Nokia de Tecnologia (INdT)
5 *
6 * Author: Anderson Lizardo <anderson.lizardo@indt.org.br>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * version 2 as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20 * 02110-1301 USA
21 *
22 * Modified from sysdeps/linux-gnu/breakpoint.c and added ARM Thumb support.
23 */
24
25#include <sys/ptrace.h>
26#include "config.h"
27#include "common.h"
28
29void
30arch_enable_breakpoint(pid_t pid, struct breakpoint *sbp)
31{
32	unsigned int i, j;
33	const unsigned char break_insn[] = BREAKPOINT_VALUE;
34	const unsigned char thumb_break_insn[] = THUMB_BREAKPOINT_VALUE;
35
36	debug(1, "arch_enable_breakpoint(%d,%p)", pid, sbp->addr);
37
38	for (i = 0; i < 1 + ((BREAKPOINT_LENGTH - 1) / sizeof(long)); i++) {
39		union _ { long l; unsigned char b[SIZEOF_LONG]; };
40		union _ orig, current;
41		unsigned char *bytes = current.b;
42		for (j = 0; j < sizeof(long); j++) {
43			orig.b[j] = sbp->orig_value[i * sizeof(long) + j];
44		}
45		current.l = ptrace(PTRACE_PEEKTEXT, pid, sbp->addr + i * sizeof(long), 0);
46
47		debug(2, "current = 0x%lx, orig_value = 0x%lx, thumb_mode = %d", current.l, orig.l, sbp->thumb_mode);
48		for (j = 0; j < sizeof(long) && i * sizeof(long) + j < BREAKPOINT_LENGTH; j++) {
49
50			sbp->orig_value[i * sizeof(long) + j] = bytes[j];
51			if (!sbp->thumb_mode) {
52				bytes[j] = break_insn[i * sizeof(long) + j];
53			}
54			else if (j < THUMB_BREAKPOINT_LENGTH) {
55				bytes[j] = thumb_break_insn[i * sizeof(long) + j];
56			}
57		}
58		ptrace(PTRACE_POKETEXT, pid, sbp->addr + i * sizeof(long), current.l);
59	}
60}
61
62void
63arch_disable_breakpoint(pid_t pid, const struct breakpoint *sbp)
64{
65	unsigned int i, j;
66
67	debug(1, "arch_disable_breakpoint(%d,%p)", pid, sbp->addr);
68
69	for (i = 0; i < 1 + ((BREAKPOINT_LENGTH - 1) / sizeof(long)); i++) {
70		union _ { long l; unsigned char b[SIZEOF_LONG]; };
71		union _ orig, current;
72		unsigned char *bytes = current.b;
73		for (j = 0; j < sizeof(long); j++) {
74			orig.b[j] = sbp->orig_value[i * sizeof(long) + j];
75		}
76		current.l = ptrace(PTRACE_PEEKTEXT, pid, sbp->addr + i * sizeof(long), 0);
77
78		debug(2, "current = 0x%lx, orig_value = 0x%lx, thumb_mode = %d", current.l, orig.l, sbp->thumb_mode);
79		for (j = 0; j < sizeof(long) && i * sizeof(long) + j < BREAKPOINT_LENGTH; j++) {
80			bytes[j] = sbp->orig_value[i * sizeof(long) + j];
81		}
82		ptrace(PTRACE_POKETEXT, pid, sbp->addr + i * sizeof(long), current.l);
83	}
84}
85
86int
87arch_breakpoint_init(struct Process *proc, struct breakpoint *sbp)
88{
89	int thumb_mode = (int)addr & 1;
90	if (thumb_mode)
91		addr = (void *)((int)addr & ~1);
92	sbp->arch.thumb_mode = thumb_mode | proc->thumb_mode;
93	proc->thumb_mode = 0;
94	return 0;
95}
96