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Filename : logging.stp
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// logging tapset
// Copyright (C) 2005-2018 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 log - Send a line to the common trace buffer
 *
 * @msg: The formatted message string
 *
 * Description: This function logs data. log sends the
 * message immediately to staprun and to the bulk transport
 * (relayfs) if it is being used. If the last character given
 * is not a newline, then one is added. This function is not 
 * as efficient as printf and should be used only for urgent
 * messages. 
 */
function log (msg:string)
%( runtime != "bpf" %?
   %{ /* unprivileged */ /* unmodified-fnargs */
	STAP_PRINTF ("%s\n", STAP_ARG_msg);
   %}
%:
   { /* unprivileged */ /* bpf */
     printf("%s\n", msg)
   }
%)

/**
 * sfunction warn - Send a line to the warning stream
 *
 * @msg: The formatted message string
 *
 * Description: This function sends a warning message immediately to 
 * staprun. It is also sent over the bulk transport (relayfs) if it is
 * being used. If the last characater is not a newline, the one is added.
 */
function warn (msg:string)
%( runtime != "bpf" %?
   %{ /* unprivileged */ /* unmodified-fnargs */
        _stp_warn ("%s", STAP_ARG_msg);
   %}
%:
   { /* unprivileged */ /* bpf */
     // TODO: _stp_warn intelligently determines whether msg has a newline
     printf("WARNING: %s\n", msg)
   }
%)


/**
 * sfunction exit - Start shutting down probing script.
 *
 * Description: This only enqueues a request to start
 * shutting down the script.  New probes will not fire
 * (except "end" probes), but all currently   
 * running ones may complete their work.
 */
function exit ()
%( runtime != "bpf" %?
  %{ /* unprivileged */
     atomic_set (session_state(), STAP_SESSION_STOPPING);
     _stp_exit ();
  %}
%:
  { /* unprivileged */ /* bpf */
    _set_exit_status()
    printf("")
  }
%)


%(systemtap_v >= "4.0" %?
/**
 * sfunction abort - Immediately shutting down probing script.
 *
 * Description: This is similar to exit() but immediately aborts
 * the current probe handler instead of waiting for its
 * completion. Probe handlers already running on *other* CPU cores,
 * however, will still continue to their completion. Unlike error(),
 * this function call cannot be caught by 'try ... catch'.
 */
function abort ()
%( runtime != "bpf" %?
  %{ /* unprivileged */
     atomic_set (session_state(), STAP_SESSION_STOPPING);
     _stp_exit ();
     CONTEXT->aborted = 1;
     CONTEXT->last_stmt = NULL;
  %}
%:
  { /* unprivileged */ /* bpf */
    _set_exit_status()
    printf("ERROR: abort() not supported in eBPF backend\n")
    exit()  /* TODO: need to abort the execution flow immediately -- could be handled with a special assembly operation */
  }
%)
%)


/**
 * sfunction error - Send an error message
 *
 * @msg: The formatted message string
 *
 * Description: An implicit end-of-line is added.  staprun prepends
 * the string "ERROR:".  Sending an error message aborts the currently
 * running probe.  Depending on the MAXERRORS parameter, it may
 * trigger an exit().
 */
function error (msg:string)
%( runtime != "bpf" %?
  %{ /* unprivileged */ /* unmodified-fnargs */
     /* NB: we used to reuse msg[] for an assignment to last_error; this
      is clearer & safer. */
     strlcpy (CONTEXT->error_buffer, STAP_ARG_msg, MAXSTRINGLEN);
     CONTEXT->last_error = CONTEXT->error_buffer;
     CONTEXT->last_stmt = NULL;
  %}
%:
   { /* unprivileged */ /* bpf */
     // TODO: should communicate an 'error' exit status
     printf("ERROR: %s\n", msg)
     exit() // TODO: should support MAXERRORS, probe error {}
   }
%)
// NOTE: The 'error' statement in the eBPF assembler in bpf-translate.cxx
// should be kept up-to-date with the behaviour of this function.

/**
 * sfunction assert - evaluate assertion
 *
 * @expression: The expression to evaluate
 *
 * Description: This function checks the expression and aborts the
 * current running probe if expression evaluates to zero. Uses error()
 * and may be caught by try{} catch{}. A default message will be
 * displayed.
 */
function assert(expression:long) { /* bpf */ /* unprivileged */
    if (!expression) {
        error("Assertion failed")
    }
}

/**
 * sfunction assert - evaluate assertion
 *
 * @expression: The expression to evaluate
 * @msg: The formatted message string
 *
 * Description: This function checks the expression and aborts the
 * current running probe if expression evaluates to zero. Uses error()
 * and may be caught by try{} catch{}. The specified message will be
 * displayed.
 */
function assert(expression:long, msg:string) { /* bpf */ /* unprivileged */
    if (!expression) {
        error(msg)
    }
}

function stp_print_binary(n:long, arg1:long, arg2:long, arg3:long, arg4:long) %{
	_stp_print_binary (STAP_ARG_n, STAP_ARG_arg1, STAP_ARG_arg2, STAP_ARG_arg3, STAP_ARG_arg4);
%}