// User context unwind tapset
// Copyright (C) 2009-2019 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.

/**
 * sfunction print_ubacktrace - Print stack back trace for current user-space task.
 *
 * Equivalent to print_ustack(ubacktrace()), except that deeper stack
 * nesting may be supported.  Returns nothing.  See print_backtrace()
 * for kernel 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 print_ubacktrace () %{ /* pragma:unwind */ /* pragma:symbols */
/* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */
    _stp_stack_user_print(CONTEXT, _STP_SYM_FULL);
%}

/**
 * sfunction print_ubacktrace - Print stack back trace for current user-space task.
 * @pc: override PC
 * @sp: override SP
 * @fp: override FP
 *
 * Equivalent to print_ubacktrace(), but it performs the backtrace
 * using the pc, sp, and fp provided.  Useful 
 *
 * 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 (pc:long, sp:long, fp:long) %{ /* pragma:unwind */ /* pragma:symbols */
/* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */
    unsigned long saved_pc, saved_sp, saved_fp;

    if (_stp_get_uregs(CONTEXT) == NULL) {
        _stp_stack_user_print(CONTEXT, _STP_SYM_FULLER); /* expecting a failure message */
        STAP_RETURN();
    }

    saved_pc = REG_IP(CONTEXT->uregs);
    saved_sp = REG_SP(CONTEXT->uregs);
    SET_REG_IP(CONTEXT->uregs, STAP_ARG_pc);
    REG_SP(CONTEXT->uregs) = STAP_ARG_sp;
#if defined REG_FP
    saved_fp = REG_FP(CONTEXT->uregs);
    REG_FP(CONTEXT->uregs) = STAP_ARG_fp;
#elif defined REG_LINK
    saved_fp = REG_LINK(CONTEXT->uregs);
    REG_LINK(CONTEXT->uregs) = STAP_ARG_fp;
#endif

    CONTEXT->uwcache_user.state = uwcache_uninitialized;
    _stp_stack_user_print(CONTEXT, _STP_SYM_FULL);
    CONTEXT->uwcache_user.state = uwcache_uninitialized;

    SET_REG_IP(CONTEXT->uregs, saved_pc);
    REG_SP(CONTEXT->uregs) = saved_sp;
#if defined REG_FP
    REG_FP(CONTEXT->uregs) = saved_fp;
#elif defined REG_LINK
    REG_LINK(CONTEXT->uregs) = saved_fp;
#endif
%}

/**
 * sfunction sprint_ubacktrace - Return stack back trace for current user-space task as string.
 *
 * 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 () %{ /* pragma:unwind */ /* pragma:symbols */
/* pure */ /* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */
    _stp_stack_user_sprint (STAP_RETVALUE, MAXSTRINGLEN, CONTEXT,
			    _STP_SYM_SIMPLE);
%}

/**
 * sfunction print_ubacktrace_brief- Print stack back trace for current user-space task.
 *
 * 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 () %{ /* pragma:unwind */ /* pragma:symbols */
/* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */
    _stp_stack_user_print(CONTEXT, _STP_SYM_BRIEF);
%}

/**
 * sfunction print_ubacktrace_fileline - Print stack back trace for current user-space task.
 *
 * Equivalent to print_ubacktrace(), but output for each symbol is
 * longer including file names and line numbers.
 *
 * 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_fileline () %{ /* pragma:unwind */ /* pragma:symbols */
/* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */ /* pragma:lines */
    _stp_stack_user_print(CONTEXT, _STP_SYM_FULLER);
%}

/**
 * sfunction print_ubacktrace - Print stack back trace for current user-space task.
 * @pc: override PC
 * @sp: override SP
 * @fp: override FP
 *
 * Equivalent to print_ubacktrace_fileline(), but it performs the backtrace
 * using the pc, sp, and fp passed in.
 *
 * 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_fileline (pc:long, sp:long, fp:long) %{ /* pragma:unwind */ /* pragma:symbols */
/* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */ /* pragma:lines */
    unsigned long saved_pc, saved_sp, saved_fp;

    if (_stp_get_uregs(CONTEXT) == NULL) {
        _stp_stack_user_print(CONTEXT, _STP_SYM_FULLER); /* expecting a failure message */
        STAP_RETURN();
    }

    saved_pc = REG_IP(CONTEXT->uregs);
    saved_sp = REG_SP(CONTEXT->uregs);
    SET_REG_IP(CONTEXT->uregs, STAP_ARG_pc);
    REG_SP(CONTEXT->uregs) = STAP_ARG_sp;
#if defined REG_FP
    saved_fp = REG_FP(CONTEXT->uregs);
    REG_FP(CONTEXT->uregs) = STAP_ARG_fp;
#elif defined REG_LINK
    saved_fp = REG_LINK(CONTEXT->uregs);
    REG_LINK(CONTEXT->uregs) = STAP_ARG_fp;
#endif

    CONTEXT->uwcache_user.state = uwcache_uninitialized;
    _stp_stack_user_print(CONTEXT, _STP_SYM_FULLER);
    CONTEXT->uwcache_user.state = uwcache_uninitialized;

    SET_REG_IP(CONTEXT->uregs, saved_pc);
    REG_SP(CONTEXT->uregs) = saved_sp;
#if defined REG_FP
    REG_FP(CONTEXT->uregs) = saved_fp;
#elif defined REG_LINK
    REG_LINK(CONTEXT->uregs) = saved_fp;
#endif
%}

/**
 * sfunction ubacktrace - Hex backtrace of current user-space task stack.
 *
 * 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.  See backtrace() for kernel traceback.
 *
 * 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 () %{ /* pragma:unwind */
/* pure */ /* myproc-unprivileged */ /* pragma:uprobes */ /* pragma:vma */
    _stp_stack_user_sprint (STAP_RETVALUE, MAXSTRINGLEN, CONTEXT,
			    _STP_SYM_NONE);
%}
