task_current_syscall — Discover what a blocked task is doing.
int task_current_syscall ( | struct task_struct * target, |
| long * callno, | |
| unsigned long args[6], | |
| unsigned int maxargs, | |
| unsigned long * sp, | |
unsigned long * pc); |
targetthread to examine
callnofilled with system call number or -1
args[6]
filled with maxargs system call arguments
maxargs
number of elements in args to fill
spfilled with user stack pointer
pcfilled with user PC
If target is blocked in a system call, returns zero with *callno
set to the the call's number and 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 *callno set to -1 and does not fill in 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.
Returns -EINVAL if maxargs is too large (maximum is six).