1
2#include <linux/ptrace.h>
3#include <linux/sched.h>
4#include <linux/sched/task_stack.h>
5#include <linux/export.h>
6#include <asm/syscall.h>
7
8static int collect_syscall(struct task_struct *target, struct syscall_info *info)
9{
10 unsigned long args[6] = { };
11 struct pt_regs *regs;
12
13 if (!try_get_task_stack(target)) {
14
15 memset(info, 0, sizeof(*info));
16 info->data.nr = -1;
17 return 0;
18 }
19
20 regs = task_pt_regs(target);
21 if (unlikely(!regs)) {
22 put_task_stack(target);
23 return -EAGAIN;
24 }
25
26 info->sp = user_stack_pointer(regs);
27 info->data.instruction_pointer = instruction_pointer(regs);
28
29 info->data.nr = syscall_get_nr(target, regs);
30 if (info->data.nr != -1L)
31 syscall_get_arguments(target, regs, args);
32
33 info->data.args[0] = args[0];
34 info->data.args[1] = args[1];
35 info->data.args[2] = args[2];
36 info->data.args[3] = args[3];
37 info->data.args[4] = args[4];
38 info->data.args[5] = args[5];
39
40 put_task_stack(target);
41 return 0;
42}
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69int task_current_syscall(struct task_struct *target, struct syscall_info *info)
70{
71 unsigned long ncsw;
72 unsigned int state;
73
74 if (target == current)
75 return collect_syscall(target, info);
76
77 state = READ_ONCE(target->__state);
78 if (unlikely(!state))
79 return -EAGAIN;
80
81 ncsw = wait_task_inactive(target, state);
82 if (unlikely(!ncsw) ||
83 unlikely(collect_syscall(target, info)) ||
84 unlikely(wait_task_inactive(target, state) != ncsw))
85 return -EAGAIN;
86
87 return 0;
88}
89