summaryrefslogtreecommitdiff
path: root/arch/um/kernel/ptrace.c
blob: 5f47422401e1e98d634d12882bd098a9c77a6207 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include <linux/audit.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/tracehook.h>
#include <linux/uaccess.h>
#include <asm/ptrace-abi.h>

void user_enable_single_step(struct task_struct *child)
{
	child->ptrace |= PT_DTRACE;
	child->thread.singlestep_syscall = 0;

#ifdef SUBARCH_SET_SINGLESTEPPING
	SUBARCH_SET_SINGLESTEPPING(child, 1);
#endif
}

void user_disable_single_step(struct task_struct *child)
{
	child->ptrace &= ~PT_DTRACE;
	child->thread.singlestep_syscall = 0;

#ifdef SUBARCH_SET_SINGLESTEPPING
	SUBARCH_SET_SINGLESTEPPING(child, 0);
#endif
}

/*
 * Called by kernel/ptrace.c when detaching..
 */
void ptrace_disable(struct task_struct *child)
{
	user_disable_single_step(child);
}

extern int peek_user(struct task_struct * child, long addr, long data);
extern int poke_user(struct task_struct * child, long addr, long data);

long arch_ptrace(struct task_struct *child, long request,
		 unsigned long addr, unsigned long data)
{
	int i, ret;
	unsigned long __user *p = (void __user *)data;
	void __user *vp = p;

	switch (request) {
	/* read the word at location addr in the USER area. */
	case PTRACE_PEEKUSR:
		ret = peek_user(child, addr, data);
		break;

	/* write the word at location addr in the USER area */
	case PTRACE_POKEUSR:
		ret = poke_user(child, addr, data);
		break;

	case PTRACE_SYSEMU:
	case PTRACE_SYSEMU_SINGLESTEP:
		ret = -EIO;
		break;

#ifdef PTRACE_GETREGS
	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
		if (!access_ok(p, MAX_REG_OFFSET)) {
			ret = -EIO;
			break;
		}
		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
			__put_user(getreg(child, i), p);
			p++;
		}
		ret = 0;
		break;
	}
#endif
#ifdef PTRACE_SETREGS
	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
		unsigned long tmp = 0;
		if (!access_ok(p, MAX_REG_OFFSET)) {
			ret = -EIO;
			break;
		}
		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
			__get_user(tmp, p);
			putreg(child, i, tmp);
			p++;
		}
		ret = 0;
		break;
	}
#endif
	case PTRACE_GET_THREAD_AREA:
		ret = ptrace_get_thread_area(child, addr, vp);
		break;

	case PTRACE_SET_THREAD_AREA:
		ret = ptrace_set_thread_area(child, addr, vp);
		break;

	default:
		ret = ptrace_request(child, request, addr, data);
		if (ret == -EIO)
			ret = subarch_ptrace(child, request, addr, data);
		break;
	}

	return ret;
}

static void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
		  int error_code)
{
	/* Send us the fake SIGTRAP */
	force_sig_fault(SIGTRAP, TRAP_BRKPT,
			/* User-mode eip? */
			UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL, tsk);
}

/*
 * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 */
int syscall_trace_enter(struct pt_regs *regs)
{
	audit_syscall_entry(UPT_SYSCALL_NR(&regs->regs),
			    UPT_SYSCALL_ARG1(&regs->regs),
			    UPT_SYSCALL_ARG2(&regs->regs),
			    UPT_SYSCALL_ARG3(&regs->regs),
			    UPT_SYSCALL_ARG4(&regs->regs));

	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		return 0;

	return tracehook_report_syscall_entry(regs);
}

void syscall_trace_leave(struct pt_regs *regs)
{
	int ptraced = current->ptrace;

	audit_syscall_exit(regs);

	/* Fake a debug trap */
	if (ptraced & PT_DTRACE)
		send_sigtrap(current, &regs->regs, 0);

	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		return;

	tracehook_report_syscall_exit(regs, 0);
	/* force do_signal() --> is_syscall() */
	if (ptraced & PT_PTRACED)
		set_thread_flag(TIF_SIGPENDING);
}