systemtap-common 1.6-1ubuntu1 / usr / share / systemtap / tapset / ucontext-unwind.stp

// User context unwind tapset
// Copyright (C) 2009-2011 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.

%{
#ifndef STP_NEED_UNWIND_DATA
#define STP_NEED_UNWIND_DATA 1
#endif
#ifndef STP_NEED_SYMBOL_DATA
#define STP_NEED_SYMBOL_DATA 1
#endif
%}

/**
 * sfunction print_ubacktrace - Print stack back trace for current task. EXPERIMENTAL!
 *
 * Equivalent to print_ustack(ubacktrace()), except that deeper stack
 * nesting may be supported.  Returns nothing.
 *
 * Note: To get (full) backtraces for user space applications and shared
 * shared libraries not mentioned in the current script run stap with
 * -d /path/to/exe-or-so and/or add --ldd to load all needed unwind data.
 */
function print_ubacktrace () %{
/* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */
  /* use task_pt_regs, CONTEXT->regs might be kernel regs, or not set. */
  if (current->mm)
    {
      struct pt_regs *uregs;
      int valid;
      if (CONTEXT->regs && (CONTEXT->regflags & _STP_REGS_USER_FLAG))
	{
	  uregs = CONTEXT->regs;
	  valid = 1;
	}
      else
	{
	  uregs = task_pt_regs(current);
	  valid = _stp_task_pt_regs_valid(current, uregs);
	}

      if (uregs)
	{
	  _stp_stack_print(uregs, _STP_SYM_FULL, CONTEXT->pi, MAXTRACE,
			   current, &CONTEXT->uwcontext, CONTEXT->ri, valid);
	  return;
	}
    }

    _stp_printf("<no ubacktrace: %s>\n", CONTEXT->probe_point);
%}

/**
 * sfunction sprint_ubacktrace - Return stack back trace for current task as string. EXPERIMENTAL!
 *
 * Returns a simple backtrace for the current task. One line per
 * address. Includes the symbol name (or hex address if symbol
 * couldn't be resolved) and module name (if found). Includes the
 * offset from the start of the function if found, otherwise the
 * offset will be added to the module (if found, between
 * brackets). Returns the backtrace as string (each line terminated by
 * a newline character).  Note that the returned stack will be
 * truncated to MAXSTRINGLEN, to print fuller and richer stacks use
 * print_ubacktrace(). Equivalent to sprint_ustack(ubacktrace()),
 * but more efficient (no need to translate between hex strings and
 * final backtrace string).
 *
 * Note: To get (full) backtraces for user space applications and shared
 * shared libraries not mentioned in the current script run stap with
 * -d /path/to/exe-or-so and/or add --ldd to load all needed unwind data.
 */
function sprint_ubacktrace:string () %{
/* pure */ /* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */
  /* use task_pt_regs, CONTEXT->regs might be kernel regs, or not set. */
  if (current->mm)
    {
      struct pt_regs *uregs;
      int valid;
      if (CONTEXT->regs && (CONTEXT->regflags & _STP_REGS_USER_FLAG))
	{
	  uregs = CONTEXT->regs;
	  valid = 1;
	}
      else
	{
	  uregs = task_pt_regs(current);
	  valid = _stp_task_pt_regs_valid(current, uregs);
	}

      if (uregs)
	{
	  _stp_stack_sprint (THIS->__retvalue, MAXSTRINGLEN, _STP_SYM_SIMPLE,
			     uregs, CONTEXT->pi, MAXTRACE,
			     current, &CONTEXT->uwcontext, CONTEXT->ri, valid);
	  return;
	}
    }

    strlcpy (THIS->__retvalue, "", MAXSTRINGLEN);
%}

/**
 * sfunction print_ubacktrace_brief- Print stack back trace for current task. EXPERIMENTAL!
 *
 * Equivalent to print_ubacktrace(), but output for each symbol is
 * shorter (just name and offset, or just the hex address of no symbol
 * could be found).
 *
 * Note: To get (full) backtraces for user space applications and shared
 * shared libraries not mentioned in the current script run stap with
 * -d /path/to/exe-or-so and/or add --ldd to load all needed unwind data.
 */
function print_ubacktrace_brief () %{
/* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */
  /* use task_pt_regs, CONTEXT->regs might be kernel regs, or not set. */
  if (current->mm)
    {
      struct pt_regs *uregs;
      int valid;
      if (CONTEXT->regs && (CONTEXT->regflags & _STP_REGS_USER_FLAG))
	{
	  uregs = CONTEXT->regs;
	  valid = 1;
	}
      else
	{
	  uregs = task_pt_regs(current);
	  valid = _stp_task_pt_regs_valid(current, uregs);
	}

      if (uregs)
	{
	  _stp_stack_print(uregs, _STP_SYM_BRIEF, CONTEXT->pi, MAXTRACE,
			   current, &CONTEXT->uwcontext, CONTEXT->ri, valid);
	  return;
	}
    }

    _stp_printf("<no ubacktrace: %s>\n", CONTEXT->probe_point);
%}

/**
 * sfunction ubacktrace - Hex backtrace of current task stack. EXPERIMENTAL!
 *
 * Return a string of hex addresses that are a backtrace of the 
 * stack of the current task.  Output may be truncated as per maximum
 * string length. Returns empty string when current probe point cannot
 * determine user backtrace.
 *
 * Note: To get (full) backtraces for user space applications and shared
 * shared libraries not mentioned in the current script run stap with
 * -d /path/to/exe-or-so and/or add --ldd to load all needed unwind data.
 */
function ubacktrace:string () %{
/* pure */ /* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */
  /* use task_pt_regs, CONTEXT->regs might be kernel regs, or not set. */
  if (current->mm)
    {
      struct pt_regs *uregs;
      int valid;
      if (CONTEXT->regs && (CONTEXT->regflags & _STP_REGS_USER_FLAG))
	{
	  uregs = CONTEXT->regs;
	  valid = 1;
	}
      else
	{
	  uregs = task_pt_regs(current);
	  valid = _stp_task_pt_regs_valid(current, uregs);
	}

      if (uregs)
	{
	  _stp_stack_sprint (THIS->__retvalue, MAXSTRINGLEN, _STP_SYM_NONE,
			     uregs, CONTEXT->pi, MAXTRACE,
			     current, &CONTEXT->uwcontext, CONTEXT->ri, valid);
	  return;
	}
    }

    strlcpy (THIS->__retvalue, "", MAXSTRINGLEN);
%}