breakpoint.c revision c0ab28673d03bdf8f264556bde0d3806ea062322 
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 <sys/types.h>
27
28#include "config.h"
29#include "breakpoint.h"
30#include "debug.h"
31#include "proc.h"
32
33void
34arch_enable_breakpoint(pid_t pid, struct breakpoint *sbp)
35{
36	unsigned int i, j;
37	const unsigned char break_insn[] = BREAKPOINT_VALUE;
38	const unsigned char thumb_break_insn[] = THUMB_BREAKPOINT_VALUE;
39
40	debug(1, "arch_enable_breakpoint(%d,%p)", pid, sbp->addr);
41
42	for (i = 0; i < 1 + ((BREAKPOINT_LENGTH - 1) / sizeof(long)); i++) {
43		union _ { long l; unsigned char b[SIZEOF_LONG]; };
44		union _ orig, current;
45		unsigned char *bytes = current.b;
46		for (j = 0; j < sizeof(long); j++) {
47			orig.b[j] = sbp->orig_value[i * sizeof(long) + j];
48		}
49		current.l = ptrace(PTRACE_PEEKTEXT, pid, sbp->addr + i * sizeof(long), 0);
50
51		debug(2, "current = 0x%lx, orig_value = 0x%lx, thumb_mode = %d",
52		      current.l, orig.l, sbp->arch.thumb_mode);
53		for (j = 0; j < sizeof(long) && i * sizeof(long) + j < BREAKPOINT_LENGTH; j++) {
54
55			sbp->orig_value[i * sizeof(long) + j] = bytes[j];
56			if (!sbp->arch.thumb_mode) {
57				bytes[j] = break_insn[i * sizeof(long) + j];
58			}
59			else if (j < THUMB_BREAKPOINT_LENGTH) {
60				bytes[j] = thumb_break_insn[i * sizeof(long) + j];
61			}
62		}
63		ptrace(PTRACE_POKETEXT, pid, sbp->addr + i * sizeof(long), current.l);
64	}
65}
66
67void
68arch_disable_breakpoint(pid_t pid, const struct breakpoint *sbp)
69{
70	unsigned int i, j;
71
72	debug(1, "arch_disable_breakpoint(%d,%p)", pid, sbp->addr);
73
74	for (i = 0; i < 1 + ((BREAKPOINT_LENGTH - 1) / sizeof(long)); i++) {
75		union _ { long l; unsigned char b[SIZEOF_LONG]; };
76		union _ orig, current;
77		unsigned char *bytes = current.b;
78		for (j = 0; j < sizeof(long); j++) {
79			orig.b[j] = sbp->orig_value[i * sizeof(long) + j];
80		}
81		current.l = ptrace(PTRACE_PEEKTEXT, pid, sbp->addr + i * sizeof(long), 0);
82
83		debug(2, "current = 0x%lx, orig_value = 0x%lx, thumb_mode = %d",
84		      current.l, orig.l, sbp->arch.thumb_mode);
85		for (j = 0; j < sizeof(long) && i * sizeof(long) + j < BREAKPOINT_LENGTH; j++) {
86			bytes[j] = sbp->orig_value[i * sizeof(long) + j];
87		}
88		ptrace(PTRACE_POKETEXT, pid, sbp->addr + i * sizeof(long), current.l);
89	}
90}
91
92int
93arch_breakpoint_init(struct Process *proc, struct breakpoint *sbp)
94{
95	/* XXX That uintptr_t cast is there temporarily until
96	 * target_address_t becomes integral type.  */
97	int thumb_mode = ((uintptr_t)sbp->addr) & 1;
98	if (thumb_mode)
99		sbp->addr = (void *)((uintptr_t)sbp->addr & ~1);
100	sbp->arch.thumb_mode = thumb_mode | proc->thumb_mode;
101	/* XXX This doesn't seem like it belongs here.  */
102	proc->thumb_mode = 0;
103	return 0;
104}
105
106void
107arch_breakpoint_destroy(struct breakpoint *sbp)
108{
109}
110
111int
112arch_breakpoint_clone(struct breakpoint *retp, struct breakpoint *sbp)
113{
114	retp->arch.thumb_mode = sbp->arch.thumb_mode;
115	return 0;
116}
117