path: root/tapset/context.stp

// context tapset
// Copyright (C) 2005-2009 Red Hat Inc.
// 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.
// <tapsetdescription>
// Context functions provide additional information about where an event occurred. These functions can 
//provide information such as a backtrace to where the event occured and the current register values for the 
//processor.
// </tapsetdescription>

%{
#include <asm/processor.h>

#if defined(__powerpc64__)
#if !defined(task_pt_regs)
#define task_pt_regs(tsk)       ((struct pt_regs *)(tsk)->thread.regs)
#endif
#endif
%}

/**
 * sfunction print_regs - Print a register dump.
 */
function print_regs () %{
	if (CONTEXT->regs) {
		_stp_print_regs (CONTEXT->regs);
	}
%}

/**
 * sfunction execname - Returns the execname of a target process (or group of processes).
 */
function execname:string () %{ /* pure */
	strlcpy (THIS->__retvalue, current->comm, MAXSTRINGLEN);
%}

/**
 * sfunction pid - Returns the ID of a target process.
 */
function pid:long () %{ /* pure */
	THIS->__retvalue = current->tgid;
%}

/**
 * sfunction tid - Returns the thread ID of a target process.
 */
function tid:long () %{ /* pure */
	THIS->__retvalue = current->pid;
%}

/**
 * sfunction ppid - Returns the process ID of a target process's parent process.
 */
function ppid:long () %{ /* pure */
#if defined(STAPCONF_REAL_PARENT)
	THIS->__retvalue = current->real_parent->tgid;
#else
	THIS->__retvalue = current->parent->tgid;
#endif
%}

/**
 * sfunction pgrp - Returns the process group ID of the current process.
 */
function pgrp:long () %{ /* pure */
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 24)
	struct signal_struct *ss = kread( &(current->signal) );
	THIS->__retvalue = kread ( &(ss->pgrp) );
	CATCH_DEREF_FAULT();
#else
	THIS->__retvalue = task_pgrp_nr_ns(current, &init_pid_ns);
#endif
%}

/**
 * sfunction sid - Returns the session ID of the current process.
 * 
 * The session ID of a process is the process group ID of the session
 * leader. Session ID is stored in the signal_struct since Kernel 2.6.0.
 */
function sid:long () %{ /* pure */
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 24)
	struct signal_struct *ss = kread( &(current->signal) );
	THIS->__retvalue = kread ( &(ss->session) );
	CATCH_DEREF_FAULT();
#else
	THIS->__retvalue = task_session_nr_ns(current, &init_pid_ns);
#endif
%}

/**
 * sfunction pexecname - Returns the execname of a target process's parent process.
 */
function pexecname:string () %{ /* pure */
#if defined(STAPCONF_REAL_PARENT)
	strlcpy (THIS->__retvalue, current->real_parent->comm, MAXSTRINGLEN);
#else
	strlcpy (THIS->__retvalue, current->parent->comm, MAXSTRINGLEN);
#endif
%}

/**
 * sfunction gid - Returns the group ID of a target process.
 */
function gid:long () %{ /* pure */
#ifdef STAPCONF_TASK_UID
	THIS->__retvalue = current->gid;		
#else
	THIS->__retvalue = current_gid();	
#endif
%}

/**
 * sfunction egid - Returns the effective gid of a target process.
 */
function egid:long () %{ /* pure */
#ifdef STAPCONF_TASK_UID
	THIS->__retvalue = current->egid;		
#else
	THIS->__retvalue = current_egid();	
#endif
%}

/**
 * sfunction uid - Returns the user ID of a target process.
 */
function uid:long () %{ /* pure */
#ifdef STAPCONF_TASK_UID
	THIS->__retvalue = current->uid;		
#else
	THIS->__retvalue = current_uid();	
#endif
%}

/**
 * sfunction euid - Return the effective uid of a target process.
 */
function euid:long () %{ /* pure */
#ifdef STAPCONF_TASK_UID
	THIS->__retvalue = current->euid;		
#else
	THIS->__retvalue = current_euid();	
#endif
%}

// cpuid() is not documented
function cpuid:long () %{ /* pure */
	THIS->__retvalue = smp_processor_id();
%}

/**
 * sfunction cpu - Returns the current cpu number.
 */
function cpu:long () %{ /* pure */
	THIS->__retvalue = smp_processor_id();
%}

/**
 * sfunction pp - Return the probe point associated with the currently running probe handler,
 * including alias and wildcard expansion effects
 * Context:
 * The current probe point. 
 */
function pp:string () %{ /* pure */
	strlcpy (THIS->__retvalue, CONTEXT->probe_point, MAXSTRINGLEN);
%}

/**
 * sfunction registers_valid - Determines validity of <command>register()</command> and <command>u_register()</command> in current context.
 *
 *  Return 1 if register() and u_register() can be used
 *  in the current context, or 0 otherwise.
 *  For example, <command>registers_valid()</command> returns 0
 *  when called from a begin or end probe.
 */
function registers_valid:long () %{ /* pure */
	THIS->__retvalue = (CONTEXT->regs != NULL);
%}

/**
 * sfunction user_mode - Determines if probe point occurs in user-mode.
 *
 * Return 1 if the probe point occurred in user-mode.
 */
function user_mode:long () %{ /* pure */ /* currently a user-mode address? */
  if (CONTEXT->regs) {
#if defined(__i386__) || defined(__x86_64__)
     THIS->__retvalue = (uint64_t) user_mode_vm (CONTEXT->regs);
#else
    THIS->__retvalue = (uint64_t) user_mode (CONTEXT->regs);
#endif
  } else {
    THIS->__retvalue = 0;
  }
%}

/**
 * sfunction is_return - Determines if probe point is a return probe.
 *
 *  Return 1 if the probe point is a return probe.
 *  <emphasis>Deprecated.</emphasis>
 */
function is_return:long () %{ /* pure */
	if (CONTEXT->pi)
		THIS->__retvalue = 1;
	else	
		THIS->__retvalue = 0;	
%}

/**
 * sfunction target - Return the process ID of the target process.
 */
function target:long () %{ /* pure */
        THIS->__retvalue = _stp_target;
%}

///<formalpara id="module_name">
///  <title>module_name:string()</title>
///  <indexterm><primary>module_name</primary></indexterm>
///  <para>
///	<remark>FIXME: need description.</remark>
///  </para>
///</formalpara>
function module_name:string () %{ /* pure */
	strlcpy(THIS->__retvalue, THIS_MODULE->name, MAXSTRINGLEN);
%}

///<formalpara id="stp_pid">
///  <title>stp_pid:long()</title>
///  <indexterm><primary>stp_pid</primary></indexterm>
///  <para>
///	<remark>FIXME: need description.</remark>
///  </para>
///</formalpara>
function stp_pid:long () %{ /* pure */
        THIS->__retvalue = _stp_pid;
%}

/**
 * sfunction stack_size - Return the size of the kernel stack.
 */
function stack_size:long () %{ /* pure */
        THIS->__retvalue = THREAD_SIZE;
%}

/**
 * sfunction stack_used - Returns the amount of kernel stack used.
 *
 * Determines how many bytes are currently used in the kernel stack.
 */
function stack_used:long () %{ /* pure */
	char a;
        THIS->__retvalue = THREAD_SIZE - ((long)&a & (THREAD_SIZE-1));
%}

/**
 * sfunction stack_unused - Returns the amount of kernel stack currently available.
 *
 * Determines how many bytes are currently available in the kernel stack.
 */
function stack_unused:long () %{ /* pure */
	char a;
        THIS->__retvalue = (long)&a & (THREAD_SIZE-1);
%}

/**
 * sfunction uaddr - User space address of current running task. EXPERIMENTAL.
 *
 * Description: Returns the address in userspace that the current
 * task was at when the probe occured. When the current running task
 * isn't a user space thread, or the address cannot be found, zero
 * is returned. Can be used to see where the current task is combined
 * with usymname() or symdata(). Often the task will be in the VDSO
 * where it entered the kernel. FIXME - need VDSO tracking support #10080.
 */
function uaddr:long () %{ /* pure */
  int64_t addr = 0;
  if (current->mm)
    {
      struct pt_regs *uregs;
      uregs = task_pt_regs(current);
      if (uregs)
        addr = (int64_t) REG_IP(uregs);
    }
  THIS->__retvalue = addr;
%}