path: root/tapset/signal.stp

// Signal tapset
// Copyright (C) 2006 IBM Corp.
// Copyright (C) 2006 Intel Corporation.
// Copyright (C) 2008 Red Hat, Inc.
//
// 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
 *  sig_pid - pid of the signal recipient process
 *  pid_name - name of the signal recipient process
 *  si_code - indicates the signal type.
 *  task - a task handle to the signal recipient
 *  sinfo - the address of siginfo struct.
 *  shared - indicates whether this signal is shared by the thread group
 *  send2queue- indicates whether this signal is sent to an existing sigqueue
 *  name - name of the function used to send out this signal
 */
probe signal.send = _signal.send.*
{
    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"
}

%( kernel_v <= "2.6.25" %?
probe _signal.send.part1 = kernel.function("__group_send_sig_info")
{
    name = "__group_send_sig_info"
    sig = $sig
    task = $p
    sinfo = $info
    shared = 1
    send2queue = 0
}

probe _signal.send.part2 = kernel.function("send_group_sigqueue")
{
    name = "send_group_sigqueue"
    sig = $sig
    task = $p
    sinfo = 0 # $q->info
    shared = 1
    send2queue = 1
}

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

%( kernel_v > "2.6.25" %?
probe _signal.send.part1 = kernel.function("send_signal")
{
    name = "__group_send_sig_info"
    sig = $sig
    task = $t
    sinfo = $info
    shared = 1
    send2queue = 0
}

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

probe _signal.send.part3 = kernel.function("send_sigqueue")
{
    name = "send_sigqueue"
%( kernel_v >=  "2.6.26" %?
    task = $t
    sig = $q->info->si_signo
%:
    task = $p
    sig = $sig
%)
    sinfo = 0 # $q->info
    shared = 0
    send2queue = 1
}

/* 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
}

%( kernel_v <= "2.6.25" %?
/*
 * - 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_sigqueue"
    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.
 *
 * Argument:
 *  sig_pid: pid of the process to be woke up
 *  pid_name: name of the process to be woke up
 *  resume: indicate whether to wake up a task in STOPPED or
            TRACED state
 *  state_mask: a string representation indicates the mask
 *              of task states that can be woken
 */
probe signal.wakeup = kernel.function("signal_wake_up")
{
    sig_pid = $t->pid
    pid_name = kernel_string($t->comm)
    resume   = $resume
    if (resume == 0) {
        state_mask = "TASK_INTERRUPTIBLE"
    } else {
        state_mask = "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 = $sig
    sig_name = _signal_name($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 = _signal.force_segv.*
{
}

probe _signal.force_segv.part1 = kernel.function("force_sigsegv")
{
    sig_pid = $p->pid
    pid_name = kernel_string($p->comm)
    sig = $sig
    sig_name = _signal_name($sig)
}

probe _signal.force_segv.part2 = kernel.function("force_sigsegv_info") ?
{
    sig_pid = pid()
    pid_name = execname()
    sig = $sig
    sig_name = _signal_name($sig)
}

probe signal.force_segv.return =
		kernel.function("force_sigsegv").return,
		kernel.function("force_sigsegv_info").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 = $sig
    sig_name = _signal_name($sig)
    sig_pid = $p->pid
    pid_name = kernel_string($p->comm)
    sigqueue_addr = $q
}

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")
{
    sigset_add=$set
    sigset_size=$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
 *  sinfo  : address of siginfo table.
 *  ka_addr : Address of the k_sigaction table associated with the signal
 *  oldset_addr : Address of a bit mask array of blocked signals
 *  regs   : Address in the Kernel Mode stack area
 *
 */
probe signal.handle = kernel.function("handle_signal")
{
    sig = $sig
    sig_name = _signal_name($sig)
    sinfo = $info
    sig_code = $info->si_code
    ka_addr = $ka
    oldset_addr =$oldset
    regs = $regs

    // Check whether the signal is a User Mode or Kernel mode Signal.

    if (sinfo == 0 && sig_code <= 0)
        sig_mode = "User Mode Signal"
    else if (sinfo >=  1)
        sig_mode = "Kernel Mode Signal"
}

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


/* probe signal.do_action
 *
 * Fires by calling thread to examine and change a signal action
 *
 * int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
 *
 * Argument :-
 *  sig    : Signal number
 *  sigact_addr  : address of the new sigaction struct associated with the signal
 *  oldsigact_addr : address of a previous sigaction struct associated with the signal
 */
probe signal.do_action = kernel.function("do_sigaction")
{
    sig = $sig
    sigact_addr = $act
    oldsigact_addr = $oact
    if(sigact_addr != 0)
    {
        sa_handler = $act->sa->sa_handler
        sa_mask = __get_action_mask($act)
    }
}

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

function __get_action_mask:long(act:long) %{ /* pure */
    int i;
    struct k_sigaction *act = (struct k_sigaction *)((long)THIS->act);
    sigset_t *sigset = &act->sa.sa_mask;
    THIS->__retvalue = kread(&(sigset->sig[0]));
    for (i=1; i<_NSIG_WORDS; ++i) {
        uint64_t part = kread(&(sigset->sig[i]));
        THIS->__retvalue |= part << (_NSIG_BPW*i);
    }
    CATCH_DEREF_FAULT();
%}


/* probe signal.procmask
 *
 * Fires by calling thread to examine and change blocked signals
 *
 * int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
 *
 * Argument :-
 *  how : indicates how to change the blocked signals. Possible
 *        values are SIG_BLOCK=0 for blocking signals, SIG_UNBLOCK=1
 *        for unblocking signals, and SIG_SETMASK=2 for setting
 *        the signal mask
 *  sigset_addr : address of sigset_t to be set
 *  oldsigset_addr : address of the old sigset_t
 *  sigset : the actual sigset to be set
 *
 */
probe signal.procmask = kernel.function("sigprocmask")
{
    how=$how
    sigset_addr = $set
    oldsigset_addr = $oldset
    sigset = get_sigset($set)
}

function get_sigset:long(sigset:long) %{ /* pure */
    int i;
    sigset_t *sigset = (sigset_t *)((long)THIS->sigset);
    THIS->__retvalue = kread(&(sigset->sig[0]));
    for (i=1; i<_NSIG_WORDS; ++i) {
        uint64_t part = kread(&(sigset->sig[i]));
        THIS->__retvalue |= part << (_NSIG_BPW*i);
    }
    CATCH_DEREF_FAULT();
%}

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)
}

function get_sa_flags:long (act:long) %{ /* pure */
	struct k_sigaction *act = (struct k_sigaction *)((long)THIS->act);
	THIS->__retvalue = kread(&act->sa.sa_flags);
	CATCH_DEREF_FAULT();
%}

function get_sa_handler:long (act:long) %{ /* pure */
	struct k_sigaction *act = (struct k_sigaction *)((long)THIS->act);
	THIS->__retvalue = (long)kread(&act->sa.sa_handler);
	CATCH_DEREF_FAULT();
%}

/*
 * sa_mask contains the set of signals to be blocked when executing the
 * signal handler. This function returns a string, delimited by ",".
 *
 * struct task_struct {
 * [...]
 *         struct signal_struct *signal;
 *         struct sighand_struct *sighand;
 * [...]
 * struct sighand_struct {
 *         atomic_t                count;
 *         struct k_sigaction      action[_NSIG];
 * [...]
 * struct k_sigaction {
 *         struct sigaction sa;
 * };
 *
 * struct sigaction {
 * [...]
 *         sigset_t sa_mask;
 * };
 */
function sigset_mask_str:string (mask:long) %{ /* pure */
	int i, len;
	char *str = THIS->__retvalue, tmp[5];
	for (i = 1; i < _NSIG; ++i, THIS->mask >>=1)
		if (THIS->mask & 1) {
			sprintf(tmp, "%u,", i);
			strlcat(str, tmp, MAXSTRINGLEN);
		}
	len = strlen(str);
	if (len) str[len - 1] = '\0';
%}

/*
 * task_struct->blocked signal mask contains the set of signals that are
 * currently blocked.
 *
 * struct task_struct {
 * [...]
 *         sigset_t blocked, real_blocked;
 */
function is_sig_blocked:long (task:long, sig:long) %{ /* pure */
	int i;
	sigset_t blocked;
	struct task_struct *p = (struct task_struct *)((long)THIS->task);
	for (i = 0; i < _NSIG_WORDS; ++i)
		blocked.sig[i] = kread(&p->blocked.sig[i]);
	THIS->__retvalue = sigismember(&blocked, THIS->sig);
	CATCH_DEREF_FAULT();
%}

function sa_flags_str:string (sa_flags:long) %{ /* pure */
	int len;
	char *str = THIS->__retvalue;
	if (THIS->sa_flags & 0x00000001u) strlcat(str, "NOCLDSTOP|", MAXSTRINGLEN);
	if (THIS->sa_flags & 0x00000002u) strlcat(str, "NOCLDWAIT|", MAXSTRINGLEN);
	if (THIS->sa_flags & 0x00000004u) strlcat(str, "SIGINFO|", MAXSTRINGLEN);
	if (THIS->sa_flags & 0x08000000u) strlcat(str, "ONSTACK|", MAXSTRINGLEN);
	if (THIS->sa_flags & 0x10000000u) strlcat(str, "RESTART|", MAXSTRINGLEN);
	if (THIS->sa_flags & 0x40000000u) strlcat(str, "NODEFER|", MAXSTRINGLEN);
	if (THIS->sa_flags & 0x80000000u) strlcat(str, "RESETHAND|", MAXSTRINGLEN);
	if (THIS->sa_flags & 0x04000000) strlcat(str, "RESTORER|", MAXSTRINGLEN);
	len = strlen(str);
	if (len) str[len - 1] = '\0';
%}

function sa_handler_str(handler) {
	if (handler == 0) return "default"; /* SIG_DFL */
	if (handler == 1) return "ignored"; /* SIG_IGN */
	if (handler == -1) return "error"; /* SIG_ERR */
	return sprintf("%p", handler); /* userspace address */
}

/*
 * Signals start from 1 not 0.
 */
global __sig[64]

function signal_str(num) {
    if (!(64 in __sig)) {
	__sig[1] = "HUP"
	__sig[2] = "INT"
	__sig[3] = "QUIT"
	__sig[4] = "ILL"
	__sig[5] = "TRAP"
	__sig[6] = "ABRT" /* or IOT */
	__sig[7] = "BUS"
	__sig[8] = "FPE"
	__sig[9] = "KILL"
	__sig[10] = "USR1"
	__sig[11] = "SEGV"
	__sig[12] = "USR2"
	__sig[13] = "PIPE"
	__sig[14] = "ALRM"
	__sig[15] = "TERM"
	__sig[16] = "STKFLT"
	__sig[17] = "CHLD" /* or CLD */
	__sig[18] = "CONT"
	__sig[19] = "STOP"
	__sig[20] = "TSTP"
	__sig[21] = "TTIN"
	__sig[22] = "TTOU"
	__sig[23] = "URG"
	__sig[24] = "XCPU"
	__sig[25] = "XFSZ"
	__sig[26] = "VTALRM"
	__sig[27] = "PROF"
	__sig[28] = "WINCH"
	__sig[29] = "IO/POLL"
	__sig[30] = "PWR"
	__sig[31] = "SYS" /* or UNUSED */
	__sig[32] = "RTMIN"
	__sig[33] = "RTMIN+1"
	__sig[34] = "RTMIN+2"
	__sig[35] = "RTMIN+3"
	__sig[36] = "RTMIN+4"
	__sig[37] = "RTMIN+5"
	__sig[38] = "RTMIN+6"
	__sig[39] = "RTMIN+7"
	__sig[40] = "RTMIN+8"
	__sig[41] = "RTMIN+9"
	__sig[42] = "RTMIN+10"
	__sig[43] = "RTMIN+11"
	__sig[44] = "RTMIN+12"
	__sig[45] = "RTMIN+13"
	__sig[46] = "RTMIN+14"
	__sig[47] = "RTMIN+15"
	__sig[48] = "RTMIN+16"
	__sig[49] = "RTMIN+17"
	__sig[50] = "RTMIN+18"
	__sig[51] = "RTMIN+19"
	__sig[52] = "RTMIN+20"
	__sig[53] = "RTMIN+21"
	__sig[54] = "RTMIN+22"
	__sig[55] = "RTMIN+23"
	__sig[56] = "RTMIN+24"
	__sig[57] = "RTMIN+25"
	__sig[58] = "RTMIN+26"
	__sig[59] = "RTMIN+27"
	__sig[60] = "RTMIN+28"
	__sig[61] = "RTMIN+29"
	__sig[62] = "RTMIN+30"
	__sig[63] = "RTMIN+31"
	__sig[64] = "RTMIN+32"
    }
    return __sig[num]
}