TASK_CURRENT_SYSCALL(9) Machine State TASK_CURRENT_SYSCALL(9)NAMEtask_current_syscall - Discover what a blocked task is doing.
SYNOPSIS
int task_current_syscall(struct task_struct * target, long * callno,
unsigned long args[6], unsigned int maxargs,
unsigned long * sp, unsigned long * pc);
ARGUMENTS
target
thread to examine
callno
filled with system call number or -1
args[6]
filled with maxargs system call arguments
maxargs
number of elements in args to fill
sp
filled with user stack pointer
pc
filled with user PC
DESCRIPTION
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).
Kernel Hackers Manual 2.6. November 2013 TASK_CURRENT_SYSCALL(9)
