path: root/tapset/signal.stp

// Signal tapset
// Copyright (C) 2006 IBM Corp.
// Copyright (C) 2006 Intel Corporation.
//
// This file is part of systemtap, and is free software.  You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.
//
//   Note : Since there are so many signals sent to processes at any give
//          point, it's better to filter the information according to the
//          requirements.  For example, filter only for a particular signal
//          (if sig==2) or filter only for a particular process
//          (if pid_name==stap).
//


/* probe signal.send
 *
 * Fires when a signal is sent to a process.
 *
 * Context:
 *  The signal's sender.
 *
 * Arguments:
 *  sig - the number of the signal
 *  sig_name - a string representation of the signal
 *  task - a task handle to the signal recipient
 *  shared - indicates whether this signal is shared by the thread group
 */
probe signal.send = _signal.send.*
{
    sig=$sig
    sig_name = _signal_name($sig)
    sig_pid = task_pid(task)
    pid_name = task_execname(task)

    if (sinfo == 2)
        si_code ="SIGSTOP or SIGKILL"
    else if (sinfo > 0)
        si_code="SI_KERNEL (SIGFPE, SIGSEGV, SIGTRAP, SIGCHLD, SIGPOLL)"
    else if (sinfo <= 0)
        si_code="SI_USER or SI_TIMER or SI_ASYNCIO"
}

probe _signal.send.part1 = kernel.function("__group_send_sig_info")
{
    name = "__group_send_sig_info"
    task = $p
    sinfo = $info
    shared = 1
    send2queue = 0
}

probe _signal.send.part2 = kernel.function("send_group_sigqueue")
{
    name = "send_group_sigqueue"
    task = $p
    sinfo = $q->info
    shared = 1
    send2queue = 1
}

probe _signal.send.part3 = kernel.function("send_sigqueue")
{
    name = "send_sigqueue"
    task = $p
    sinfo = $q->info
    shared = 0
    send2queue = 1
}

probe _signal.send.part4 = kernel.function("specific_send_sig_info")
{
    name = "specific_send_sig_info"
    task = $t
    sinfo = $info
    shared = 0
    send2queue = 0
}

/* probe signal.send.return
 */
probe signal.send.return = _signal.send.*.return
{
    retstr = returnstr(1)
}

/* 
 * Return values for "__group_send_sig_info" and "specific_send_sig_info"
 *
 * - return 0 if  the signal is sucessfully sent to a process, 
 *   which means the following:
 *     <1> the signal is ignored by receiving process
 *     <2> this is a non-RT signal and we already have one queued
 *     <3> the signal is successfully added into the sigqueue of 
 *        receiving process
 *
 * - return -EAGAIN if the sigqueue is overflow the signal was RT
 *   and sent by user using something other than kill()
 *
 */
probe _signal.send.part1.return = kernel.function("__group_send_sig_info").return
{
    name = "__group_send_sig_info"
    shared = 1
    send2queue = 0
}

probe _signal.send.part4.return = kernel.function("specific_send_sig_info").return
{
    name = "specific_send_sig_info"
    shared = 0
    send2queue = 0
}

/*
 * - return 0 if the signal is either sucessfully added into the 
 *   sigqueue of receiving process or a SI_TIMER entry is already
 *   queued so just increment the overrun count
 *
 * - return 1 if this signal is ignored by receiving process
 *
 */
probe _signal.send.part2.return = kernel.function("send_group_sigqueue").return
{
    name = "send_group_sigqueue"
    shared = 1
    send2queue = 1
}

/*
 * - return 0 if the signal is either sucessfully added into the 
 *   sigqueue of receiving process or a SI_TIMER entry is already
 *   queued so just increment the overrun count
 *
 * - return 1 if this signal is ignored by receiving process
 *
 * - return -1 if the task is marked exiting, so posix_timer_event
 *   can redirect it to the group leader
 *
 */

probe _signal.send.part3.return = kernel.function("send_sigqueue").return
{
    name = "send_sigqueueu"
    shared = 0
    send2queue = 1
}

/* probe signal.checkperm
 *
 *  check permissions for sending the signal
 *
 */
probe signal.checkperm = kernel.function("check_kill_permission")
{
    sig = $sig
    task = $t
    sinfo = $info
    name = "signal.checkperm"

    sig_name = _signal_name($sig)
    sig_pid = task_pid(task)
    pid_name = task_execname(task)

    if (sinfo == 2)
        si_code ="SIGSTOP or SIGKILL"
    else if (sinfo > 0)
        si_code="SI_KERNEL (SIGFPE, SIGSEGV, SIGTRAP, SIGCHLD, SIGPOLL)"
    else if (sinfo <= 0)
        si_code="SI_USER or SI_TIMER or SI_ASYNCIO"
}  

probe signal.checkperm.return = kernel.function("check_kill_permission").return
{
    name = "signal.checkperm"
    retstr = returnstr(1)
}
	

/* probe signal.wakeup
 *
 * Wake up the process for new active signals.
 *
 */
probe signal.wakeup = kernel.function("signal_wake_up")
{
    sig_pid = $t->pid
    pid_name = kernel_string($t->comm)
    state   = $resume
    if (state == 0) {
        sig_state = "TASK_INTERRUPTIBLE"
    } else {
        sig_state = "TASK_INTERRUPTIBLE | TASK_STOPPED | TASK_TRACED"
    }
}


/* probe signal.ignored
 *
 *  Checks whether the signal is ignored or not.
 *
 */
probe signal.check_ignored = kernel.function("sig_ignored")
{
    sig_pid = $t->pid
    pid_name = kernel_string($t->comm)
    sig_info = $sig
    sig_name = _signal_name($sig)
}

probe signal.check_ignored.return = kernel.function("sig_ignored").return
{
    name = "sig_ignored"
    retstr = returnstr(1)
}


/* probe signal.handle_stop
 *
 *  For now, just comment it out since at the time handle_stop_signal()
 *  is called, it doesn't know whether current signal is STOP/COUNT. 
 *  So the calling of handle_stop_signal() doesn't mean that the Kernel
 *  is now processing the STOP/COUNT signal
 *
 */
/*
probe signal.handle_stop = kernel.function("handle_stop_signal")
{
    sig_pid = $p->pid
    pid_name = kernel_string($p->comm)
    sig_info = $sig
    sig_name = _signal_name($sig)
}
*/


/* probe signal.force_segv
 *
 *  Forces SIGSEGV when there are some issues while handling signals for the process.
 *
 */
probe signal.force_segv = kernel.function("force_sigsegv")
{
    sig_pid = $p->pid
    pid_name = kernel_string($p->comm)
    sig_info = $sig
    sig_name = _signal_name($sig)
}

probe signal.force_segv.return = kernel.function("force_sigsegv").return
{
    name = "force_sigsegv"
    retstr = returnstr(1)
}


/* probe signal.syskill
 *
 *  To kill a process, Pass the pid and signal to kill the process.
 *
 */
probe signal.syskill = syscall.kill
{
    sig_name = _signal_name($sig)
}

probe signal.syskill.return = syscall.kill.return
{
}


/* probe signal.sys_tgkill
 *
 *  Sends a signal to one specific thread.
 *
 */
probe signal.systgkill = syscall.tgkill
{
    sig_name = _signal_name($sig)
}

probe signal.systgkill.return = syscall.tgkill.return
{
}


/* probe signal.sys_tkill
 *
 *  Sends a signal to one specific task.
 *
 */
probe signal.systkill = syscall.tkill
{
    sig_name = _signal_name($sig)
}

probe signal.systkill.return = syscall.tkill.return
{
}


/* probe signal.send_sig_queue
 *
 * Queue signal to a process.
 *
 */
probe signal.send_sig_queue =
        kernel.function("send_sigqueue"),
        kernel.function("send_group_sigqueue")
{
    sig_info = $sig
    sig_name = _signal_name($sig)
    sig_pid = $p->pid
    pid_name = kernel_string($p->comm)
    user_id = $q->uid
    nos_process = $q->processes
    nos_pending_sig = $q->sigpending
}

probe signal.send_sig_queue.return =
        kernel.function("send_sigqueue").return,
        kernel.function("send_group_sigqueue").return
{
    retstr = returnstr(1)
}


/* probe signal.pending
 *
 * Used to examine the set of signals that are pending for 
 * delivery to the calling thread
 *
 * long do_sigpending(void __user *set, unsigned long sigsetsize)
 */
probe signal.pending = kernel.function("do_sigpending")
{
    uspace_add=$set
    sset_size=$sigsetsize
}

probe signal.pending.return = kernel.function("do_sigpending").return
{
    retstr = returnstr(1)
}


/* probe signal.handle
 *
 * Used to invoke signals
 *
 * static int handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 *					sigset_t *oldset, struct pt_regs * regs)
 * Argument :-
 *  sig    : Signal number
 *  info   : address of siginfo table.
 *  ka     : Address of the k_sigaction table associated with the signal
 *  oldset : Address of a bit mask array of blocked signals
 *  regs   : Address in the Kernel Mode stack area 
 *  
 */
probe signal.handle = kernel.function("handle_signal")?,
        kernel.inline("handle_signal")?
{
    sig = $sig
    sig_name = _signal_name($sig)
    sinfo_addr = $info
    sig_code = $info->si_code
    sig_stack_add=$ka
    bitmask_add=$oldset
    kernmode_stack_add=$regs

    // Check whether the signal is a User Mode or Kernel mode Signal.
    
    if (sinfo_addr == 0 && sig_code <= 0)
        sig_mode = "User Mode Signal"
    else if (sinfo_addr >=  1)
        sig_mode = "Kernel Mode Signal"
}

probe signal.handle.return = kernel.function("handle_signal").return
{
    retstr = returnstr(1)
}


/* probe signal.do_action
 *
 * Called by sys_sigaction() to copy the new new_ka table into the entry at the sig-1 position.
 *
 * int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
 *
 * Argument :-
 *  sig    : Signal number
 *  act    : Address of the sigaction table associated with the signal
 *  oact   : Address of a previous sigaction table
 *
 */
probe signal.do_action = kernel.function("do_sigaction")
{
    sig = $sig
    sigact_table=$act
    psigact_table=$oact
    if(sigact_table != 0)
    {
         sa_handler = $act->sa->sa_handler
         sa_mask = $act->sa->sa_mask
    }
}

probe signal.do_action.return = kernel.function("do_sigaction").return
{
    retstr = returnstr(1)
}


/* probe signal.procmask
 *
 * Allows processes to modify the set of blocked signals.
 *
 * int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
 *
 * Argument :-
 *  how    : Flag having one of the values (SIG_BLOCK, SIG_UNBLOCK, SIG_SETMASK)
 *  set    : Address of the process address space to a bit array.
 *  oldset : Address of the process address space where the previous bit mask must be stored.
 *
 */
probe signal.procmask = kernel.function("sigprocmask")
{
    stemp=$how
    sigset_addr = $set
    sigoset_addr = $oldset

    sigset = get_sigset($set)
    if (stemp == 0)
        sig_how ="SIG_BLOCK"
    else if (stemp ==  1)
        sig_how="SIG_UNBLOCK"
    else if (stemp == 2)
        sig_how="SIG_SETMASK"
}

function get_sigset:long(sigset:long) %{ /* pure */

    sigset_t *sigset = (sigset_t *)((long)THIS->sigset);

if(_NSIG_BPW == 64)
    THIS->__retvalue = deref(sizeof(sigset_t), sigset);
else if(_NSIG_BPW == 32)
    THIS->__retvalue = deref(sizeof(int), &(sigset->sig[0])) |
        ((u_int64_t)deref(sizeof(int), &(sigset->sig[1])))<<32;

    if(0)  {
deref_fault:
        CONTEXT->last_error = "pointer deref error";
    }
%}

probe signal.procmask.return = kernel.function("sigprocmask").return
{
    retstr = returnstr(1)
}


/*
 * probe signal.flush
 * 
 * Flush all pending signals for a task.
 *
 * void flush_signals(struct task_struct *t)
 *
 */
probe signal.flush = kernel.function("flush_signals")
{
    task = $t
    sig_pid = $t->pid
    pid_name = kernel_string($t->comm)
}