summaryrefslogtreecommitdiffstats
path: root/arch/um/kernel/ptrace.c
blob: db55a017e9b91fb1ea2a5b9d33be7e710684491e (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
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
/*
 * 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 "asm/uaccess.h"
#ifdef CONFIG_PROC_MM
#include "proc_mm.h"
#endif
#include "skas_ptrace.h"

static inline void set_singlestepping(struct task_struct *child, int on)
{
	if (on)
		child->ptrace |= PT_DTRACE;
	else
		child->ptrace &= ~PT_DTRACE;
	child->thread.singlestep_syscall = 0;

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

/*
 * Called by kernel/ptrace.c when detaching..
 */
void ptrace_disable(struct task_struct *child)
{
	set_singlestepping(child,0);
}

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, long addr, long data)
{
	int i, ret;
	unsigned long __user *p = (void __user *)(unsigned long)data;

	switch (request) {
	/* read word at location addr. */
	case PTRACE_PEEKTEXT:
	case PTRACE_PEEKDATA:
		ret = generic_ptrace_peekdata(child, addr, data);
		break;

	/* 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. */
	case PTRACE_POKETEXT:
	case PTRACE_POKEDATA:
		ret = generic_ptrace_pokedata(child, addr, data);
		break;

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

	/* continue and stop at next (return from) syscall */
	case PTRACE_SYSCALL:
	/* restart after signal. */
	case PTRACE_CONT: {
		ret = -EIO;
		if (!valid_signal(data))
			break;

		set_singlestepping(child, 0);
		if (request == PTRACE_SYSCALL)
			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		else clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		child->exit_code = data;
		wake_up_process(child);
		ret = 0;
		break;
	}

/*
 * make the child exit.  Best I can do is send it a sigkill.
 * perhaps it should be put in the status that it wants to
 * exit.
 */
	case PTRACE_KILL: {
		ret = 0;
		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
			break;

		set_singlestepping(child, 0);
		child->exit_code = SIGKILL;
		wake_up_process(child);
		break;
	}

	case PTRACE_SINGLESTEP: {  /* set the trap flag. */
		ret = -EIO;
		if (!valid_signal(data))
			break;
		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		set_singlestepping(child, 1);
		child->exit_code = data;
		/* give it a chance to run. */
		wake_up_process(child);
		ret = 0;
		break;
	}

#ifdef PTRACE_GETREGS
	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
		if (!access_ok(VERIFY_WRITE, 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(VERIFY_READ, 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
#ifdef PTRACE_GETFPREGS
	case PTRACE_GETFPREGS: /* Get the child FPU state. */
		ret = get_fpregs(data, child);
		break;
#endif
#ifdef PTRACE_SETFPREGS
	case PTRACE_SETFPREGS: /* Set the child FPU state. */
	        ret = set_fpregs(data, child);
		break;
#endif
#ifdef PTRACE_GETFPXREGS
	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
		ret = get_fpxregs(data, child);
		break;
#endif
#ifdef PTRACE_SETFPXREGS
	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
		ret = set_fpxregs(data, child);
		break;
#endif
	case PTRACE_GET_THREAD_AREA:
		ret = ptrace_get_thread_area(child, addr,
					     (struct user_desc __user *) data);
		break;

	case PTRACE_SET_THREAD_AREA:
		ret = ptrace_set_thread_area(child, addr,
					     (struct user_desc __user *) data);
		break;

	case PTRACE_FAULTINFO: {
		/*
		 * Take the info from thread->arch->faultinfo,
		 * but transfer max. sizeof(struct ptrace_faultinfo).
		 * On i386, ptrace_faultinfo is smaller!
		 */
		ret = copy_to_user(p, &child->thread.arch.faultinfo,
				   sizeof(struct ptrace_faultinfo));
		if (ret)
			break;
		break;
	}

#ifdef PTRACE_LDT
	case PTRACE_LDT: {
		struct ptrace_ldt ldt;

		if (copy_from_user(&ldt, p, sizeof(ldt))) {
			ret = -EIO;
			break;
		}

		/*
		 * This one is confusing, so just punt and return -EIO for
		 * now
		 */
		ret = -EIO;
		break;
	}
#endif
#ifdef CONFIG_PROC_MM
	case PTRACE_SWITCH_MM: {
		struct mm_struct *old = child->mm;
		struct mm_struct *new = proc_mm_get_mm(data);

		if (IS_ERR(new)) {
			ret = PTR_ERR(new);
			break;
		}

		atomic_inc(&new->mm_users);
		child->mm = new;
		child->active_mm = new;
		mmput(old);
		ret = 0;
		break;
	}
#endif
#ifdef PTRACE_ARCH_PRCTL
	case PTRACE_ARCH_PRCTL:
		/* XXX Calls ptrace on the host - needs some SMP thinking */
		ret = arch_prctl(child, data, (void *) addr);
		break;
#endif
	default:
		ret = ptrace_request(child, request, addr, data);
		break;
	}

	return ret;
}

void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
		  int error_code)
{
	struct siginfo info;

	memset(&info, 0, sizeof(info));
	info.si_signo = SIGTRAP;
	info.si_code = TRAP_BRKPT;

	/* User-mode eip? */
	info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;

	/* Send us the fakey SIGTRAP */
	force_sig_info(SIGTRAP, &info, tsk);
}

/*
 * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 */
void syscall_trace(struct uml_pt_regs *regs, int entryexit)
{
	int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
	int tracesysgood;

	if (unlikely(current->audit_context)) {
		if (!entryexit)
			audit_syscall_entry(HOST_AUDIT_ARCH,
					    UPT_SYSCALL_NR(regs),
					    UPT_SYSCALL_ARG1(regs),
					    UPT_SYSCALL_ARG2(regs),
					    UPT_SYSCALL_ARG3(regs),
					    UPT_SYSCALL_ARG4(regs));
		else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
					UPT_SYSCALL_RET(regs));
	}

	/* Fake a debug trap */
	if (is_singlestep)
		send_sigtrap(current, regs, 0);

	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		return;

	if (!(current->ptrace & PT_PTRACED))
		return;

	/*
	 * the 0x80 provides a way for the tracing parent to distinguish
	 * between a syscall stop and SIGTRAP delivery
	 */
	tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
	ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));

	if (entryexit) /* force do_signal() --> is_syscall() */
		set_thread_flag(TIF_SIGPENDING);

	/*
	 * this isn't the same as continuing with a signal, but it will do
	 * for normal use.  strace only continues with a signal if the
	 * stopping signal is not SIGTRAP.  -brl
	 */
	if (current->exit_code) {
		send_sig(current->exit_code, current, 1);
		current->exit_code = 0;
	}
}