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
|
#include <linux/kernel.h>
#include <linux/ftrace.h>
#include <asm/syscall.h>
#include "trace_output.h"
#include "trace.h"
static atomic_t refcount;
/* Our two options */
enum {
TRACE_SYSCALLS_OPT_TYPES = 0x1,
};
static struct tracer_opt syscalls_opts[] = {
{ TRACER_OPT(syscall_arg_type, TRACE_SYSCALLS_OPT_TYPES) },
{ }
};
static struct tracer_flags syscalls_flags = {
.val = 0, /* By default: no args types */
.opts = syscalls_opts
};
enum print_line_t
print_syscall_enter(struct trace_iterator *iter, int flags)
{
struct trace_seq *s = &iter->seq;
struct trace_entry *ent = iter->ent;
struct syscall_trace_enter *trace;
struct syscall_metadata *entry;
int i, ret, syscall;
trace_assign_type(trace, ent);
syscall = trace->nr;
entry = syscall_nr_to_meta(syscall);
if (!entry)
goto end;
ret = trace_seq_printf(s, "%s(", entry->name);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
for (i = 0; i < entry->nb_args; i++) {
/* parameter types */
if (syscalls_flags.val & TRACE_SYSCALLS_OPT_TYPES) {
ret = trace_seq_printf(s, "%s ", entry->types[i]);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
/* parameter values */
ret = trace_seq_printf(s, "%s: %lx%s ", entry->args[i],
trace->args[i],
i == entry->nb_args - 1 ? ")" : ",");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
end:
trace_seq_printf(s, "\n");
return TRACE_TYPE_HANDLED;
}
enum print_line_t
print_syscall_exit(struct trace_iterator *iter, int flags)
{
struct trace_seq *s = &iter->seq;
struct trace_entry *ent = iter->ent;
struct syscall_trace_exit *trace;
int syscall;
struct syscall_metadata *entry;
int ret;
trace_assign_type(trace, ent);
syscall = trace->nr;
entry = syscall_nr_to_meta(syscall);
if (!entry) {
trace_seq_printf(s, "\n");
return TRACE_TYPE_HANDLED;
}
ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
trace->ret);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
return TRACE_TYPE_HANDLED;
}
void start_ftrace_syscalls(void)
{
unsigned long flags;
struct task_struct *g, *t;
/* Don't enable the flag on the tasks twice */
if (atomic_inc_return(&refcount) != 1)
return;
arch_init_ftrace_syscalls();
read_lock_irqsave(&tasklist_lock, flags);
do_each_thread(g, t) {
set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
} while_each_thread(g, t);
read_unlock_irqrestore(&tasklist_lock, flags);
}
void stop_ftrace_syscalls(void)
{
unsigned long flags;
struct task_struct *g, *t;
/* There are perhaps still some users */
if (atomic_dec_return(&refcount))
return;
read_lock_irqsave(&tasklist_lock, flags);
do_each_thread(g, t) {
clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
} while_each_thread(g, t);
read_unlock_irqrestore(&tasklist_lock, flags);
}
void ftrace_syscall_enter(struct pt_regs *regs)
{
struct syscall_trace_enter *entry;
struct syscall_metadata *sys_data;
struct ring_buffer_event *event;
int size;
int syscall_nr;
int cpu;
syscall_nr = syscall_get_nr(current, regs);
cpu = raw_smp_processor_id();
sys_data = syscall_nr_to_meta(syscall_nr);
if (!sys_data)
return;
size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
event = trace_current_buffer_lock_reserve(TRACE_SYSCALL_ENTER, size,
0, 0);
if (!event)
return;
entry = ring_buffer_event_data(event);
entry->nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
trace_current_buffer_unlock_commit(event, 0, 0);
trace_wake_up();
}
void ftrace_syscall_exit(struct pt_regs *regs)
{
struct syscall_trace_exit *entry;
struct syscall_metadata *sys_data;
struct ring_buffer_event *event;
int syscall_nr;
int cpu;
syscall_nr = syscall_get_nr(current, regs);
cpu = raw_smp_processor_id();
sys_data = syscall_nr_to_meta(syscall_nr);
if (!sys_data)
return;
event = trace_current_buffer_lock_reserve(TRACE_SYSCALL_EXIT,
sizeof(*entry), 0, 0);
if (!event)
return;
entry = ring_buffer_event_data(event);
entry->nr = syscall_nr;
entry->ret = syscall_get_return_value(current, regs);
trace_current_buffer_unlock_commit(event, 0, 0);
trace_wake_up();
}
static int init_syscall_tracer(struct trace_array *tr)
{
start_ftrace_syscalls();
return 0;
}
static void reset_syscall_tracer(struct trace_array *tr)
{
stop_ftrace_syscalls();
tracing_reset_online_cpus(tr);
}
static struct trace_event syscall_enter_event = {
.type = TRACE_SYSCALL_ENTER,
.trace = print_syscall_enter,
};
static struct trace_event syscall_exit_event = {
.type = TRACE_SYSCALL_EXIT,
.trace = print_syscall_exit,
};
static struct tracer syscall_tracer __read_mostly = {
.name = "syscall",
.init = init_syscall_tracer,
.reset = reset_syscall_tracer,
.flags = &syscalls_flags,
};
__init int register_ftrace_syscalls(void)
{
int ret;
ret = register_ftrace_event(&syscall_enter_event);
if (!ret) {
printk(KERN_WARNING "event %d failed to register\n",
syscall_enter_event.type);
WARN_ON_ONCE(1);
}
ret = register_ftrace_event(&syscall_exit_event);
if (!ret) {
printk(KERN_WARNING "event %d failed to register\n",
syscall_exit_event.type);
WARN_ON_ONCE(1);
}
return register_tracer(&syscall_tracer);
}
device_initcall(register_ftrace_syscalls);
|
