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
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
*/
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/ftrace.h>
#include <asm/siginfo.h>
#include <asm/signal.h>
#include <asm/unistd.h>
#include <frame_kern.h>
#include <kern_util.h>
#include <os.h>
EXPORT_SYMBOL(block_signals);
EXPORT_SYMBOL(unblock_signals);
void block_signals_trace(void)
{
block_signals();
if (current_thread_info())
trace_hardirqs_off();
}
void unblock_signals_trace(void)
{
if (current_thread_info())
trace_hardirqs_on();
unblock_signals();
}
void um_trace_signals_on(void)
{
if (current_thread_info())
trace_hardirqs_on();
}
void um_trace_signals_off(void)
{
if (current_thread_info())
trace_hardirqs_off();
}
/*
* OK, we're invoking a handler
*/
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
sigset_t *oldset = sigmask_to_save();
int singlestep = 0;
unsigned long sp;
int err;
if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
singlestep = 1;
/* Did we come from a system call? */
if (PT_REGS_SYSCALL_NR(regs) >= 0) {
/* If so, check system call restarting.. */
switch (PT_REGS_SYSCALL_RET(regs)) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
PT_REGS_SYSCALL_RET(regs) = -EINTR;
break;
case -ERESTARTSYS:
if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
PT_REGS_SYSCALL_RET(regs) = -EINTR;
break;
}
fallthrough;
case -ERESTARTNOINTR:
PT_REGS_RESTART_SYSCALL(regs);
PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
break;
}
}
sp = PT_REGS_SP(regs);
if ((ksig->ka.sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
sp = current->sas_ss_sp + current->sas_ss_size;
#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
if (!(ksig->ka.sa.sa_flags & SA_SIGINFO))
err = setup_signal_stack_sc(sp, ksig, regs, oldset);
else
#endif
err = setup_signal_stack_si(sp, ksig, regs, oldset);
signal_setup_done(err, ksig, singlestep);
}
void do_signal(struct pt_regs *regs)
{
struct ksignal ksig;
int handled_sig = 0;
while (get_signal(&ksig)) {
handled_sig = 1;
/* Whee! Actually deliver the signal. */
handle_signal(&ksig, regs);
}
/* Did we come from a system call? */
if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
/* Restart the system call - no handlers present */
switch (PT_REGS_SYSCALL_RET(regs)) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
PT_REGS_RESTART_SYSCALL(regs);
break;
case -ERESTART_RESTARTBLOCK:
PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
PT_REGS_RESTART_SYSCALL(regs);
break;
}
}
/*
* This closes a way to execute a system call on the host. If
* you set a breakpoint on a system call instruction and singlestep
* from it, the tracing thread used to PTRACE_SINGLESTEP the process
* rather than PTRACE_SYSCALL it, allowing the system call to execute
* on the host. The tracing thread will check this flag and
* PTRACE_SYSCALL if necessary.
*/
if (current->ptrace & PT_DTRACE)
current->thread.singlestep_syscall =
is_syscall(PT_REGS_IP(¤t->thread.regs));
/*
* if there's no signal to deliver, we just put the saved sigmask
* back
*/
if (!handled_sig)
restore_saved_sigmask();
}
|
