forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
88 lines
2.7 KiB
88 lines
2.7 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
#include <linux/ptrace.h> |
|
#include <linux/sched.h> |
|
#include <linux/sched/task_stack.h> |
|
#include <linux/export.h> |
|
#include <asm/syscall.h> |
|
|
|
static int collect_syscall(struct task_struct *target, struct syscall_info *info) |
|
{ |
|
unsigned long args[6] = { }; |
|
struct pt_regs *regs; |
|
|
|
if (!try_get_task_stack(target)) { |
|
/* Task has no stack, so the task isn't in a syscall. */ |
|
memset(info, 0, sizeof(*info)); |
|
info->data.nr = -1; |
|
return 0; |
|
} |
|
|
|
regs = task_pt_regs(target); |
|
if (unlikely(!regs)) { |
|
put_task_stack(target); |
|
return -EAGAIN; |
|
} |
|
|
|
info->sp = user_stack_pointer(regs); |
|
info->data.instruction_pointer = instruction_pointer(regs); |
|
|
|
info->data.nr = syscall_get_nr(target, regs); |
|
if (info->data.nr != -1L) |
|
syscall_get_arguments(target, regs, args); |
|
|
|
info->data.args[0] = args[0]; |
|
info->data.args[1] = args[1]; |
|
info->data.args[2] = args[2]; |
|
info->data.args[3] = args[3]; |
|
info->data.args[4] = args[4]; |
|
info->data.args[5] = args[5]; |
|
|
|
put_task_stack(target); |
|
return 0; |
|
} |
|
|
|
/** |
|
* task_current_syscall - Discover what a blocked task is doing. |
|
* @target: thread to examine |
|
* @info: structure with the following fields: |
|
* .sp - filled with user stack pointer |
|
* .data.nr - filled with system call number or -1 |
|
* .data.args - filled with @maxargs system call arguments |
|
* .data.instruction_pointer - filled with user PC |
|
* |
|
* If @target is blocked in a system call, returns zero with @info.data.nr |
|
* set to the call's number and @info.data.args filled in with its |
|
* arguments. Registers not used for system call arguments may not be available |
|
* and it is not kosher to use &struct user_regset calls while the system |
|
* call is still in progress. Note we may get this result if @target |
|
* has finished its system call but not yet returned to user mode, such |
|
* as when it's stopped for signal handling or syscall exit tracing. |
|
* |
|
* If @target is blocked in the kernel during a fault or exception, |
|
* returns zero with *@info.data.nr set to -1 and does not fill in |
|
* @info.data.args. If so, it's now safe to examine @target using |
|
* &struct user_regset get() calls as long as we're sure @target won't return |
|
* to user mode. |
|
* |
|
* Returns -%EAGAIN if @target does not remain blocked. |
|
*/ |
|
int task_current_syscall(struct task_struct *target, struct syscall_info *info) |
|
{ |
|
long state; |
|
unsigned long ncsw; |
|
|
|
if (target == current) |
|
return collect_syscall(target, info); |
|
|
|
state = target->state; |
|
if (unlikely(!state)) |
|
return -EAGAIN; |
|
|
|
ncsw = wait_task_inactive(target, state); |
|
if (unlikely(!ncsw) || |
|
unlikely(collect_syscall(target, info)) || |
|
unlikely(wait_task_inactive(target, state) != ncsw)) |
|
return -EAGAIN; |
|
|
|
return 0; |
|
}
|
|
|