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// kretprobe data tapset
// Copyright (C) 2009 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.
// This is an internally-used tapset for sharing data between kretprobe
// entry / return handlers. See the function
// dwarf_var_expanding_visitor::gen_kretprobe_saved_return
// for details.
//
// Note, invalid calls are silently ignored...
%{
static void *
_kretprobe_data(struct kretprobe_instance *pi, size_t offset, size_t length)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25)
size_t end = offset + length;
if (end > offset && pi && end <= pi->rp->data_size)
return &pi->data[offset];
#endif
return NULL;
}
%}
function _get_kretprobe_long:long(i:long) %{ /* pure */
size_t offset = THIS->i * sizeof(int64_t);
const int64_t *data = _kretprobe_data(CONTEXT->pi, offset, sizeof(int64_t));
THIS->__retvalue = data ? *data : 0;
%}
function _set_kretprobe_long(i:long, value:long) %{ /* impure */
size_t offset = THIS->i * sizeof(int64_t);
int64_t *data = _kretprobe_data(CONTEXT->pi, offset, sizeof(int64_t));
if (data)
*data = THIS->value;
%}
function _get_kretprobe_string:string(i:long) %{ /* pure */
size_t offset = CONTEXT->pi_longs * sizeof(int64_t) +
THIS->i * MAXSTRINGLEN;
const char *data = _kretprobe_data(CONTEXT->pi, offset, MAXSTRINGLEN);
strlcpy(THIS->__retvalue, data ?: "", MAXSTRINGLEN);
%}
function _set_kretprobe_string(i:long, value:string) %{ /* impure */
size_t offset = CONTEXT->pi_longs * sizeof(int64_t) +
THIS->i * MAXSTRINGLEN;
char *data = _kretprobe_data(CONTEXT->pi, offset, MAXSTRINGLEN);
if (data)
strlcpy(data, THIS->value, MAXSTRINGLEN);
%}
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