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, long *callno,
9 unsigned long args[6], unsigned int maxargs,
10 unsigned long *sp, unsigned long *pc)
11{
12 struct pt_regs *regs;
13
14 if (!try_get_task_stack(target)) {
15
16 *sp = *pc = 0;
17 *callno = -1;
18 return 0;
19 }
20
21 regs = task_pt_regs(target);
22 if (unlikely(!regs)) {
23 put_task_stack(target);
24 return -EAGAIN;
25 }
26
27 *sp = user_stack_pointer(regs);
28 *pc = instruction_pointer(regs);
29
30 *callno = syscall_get_nr(target, regs);
31 if (*callno != -1L && maxargs > 0)
32 syscall_get_arguments(target, regs, 0, maxargs, args);
33
34 put_task_stack(target);
35 return 0;
36}
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63
64int task_current_syscall(struct task_struct *target, long *callno,
65 unsigned long args[6], unsigned int maxargs,
66 unsigned long *sp, unsigned long *pc)
67{
68 long state;
69 unsigned long ncsw;
70
71 if (unlikely(maxargs > 6))
72 return -EINVAL;
73
74 if (target == current)
75 return collect_syscall(target, callno, args, maxargs, sp, pc);
76
77 state = 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, callno, args, maxargs, sp, pc)) ||
84 unlikely(wait_task_inactive(target, state) != ncsw))
85 return -EAGAIN;
86
87 return 0;
88}
89