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// tapset for begin/end/error/never
// Copyright (C) 2005-2010 Red Hat Inc.
// Copyright (C) 2005-2007 Intel Corporation.
// Copyright (C) 2008 James.Bottomley@HansenPartnership.com
//
// 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.
#include "session.h"
#include "tapsets.h"
#include "translate.h"
#include "util.h"
#include <algorithm>
#include <string>
using namespace std;
using namespace __gnu_cxx;
static const string TOK_BEGIN("begin");
static const string TOK_END("end");
static const string TOK_ERROR("error");
static const string TOK_NEVER("never");
// ------------------------------------------------------------------------
// begin/end/error probes are run right during registration / deregistration
// ------------------------------------------------------------------------
enum be_t { BEGIN, END, ERROR };
struct be_derived_probe: public derived_probe
{
be_t type;
int64_t priority;
be_derived_probe (probe* p, probe_point* l, be_t t, int64_t pr):
derived_probe (p, l), type (t), priority (pr) {}
void join_group (systemtap_session& s);
static inline bool comp(be_derived_probe const *a,
be_derived_probe const *b)
{
// This allows the BEGIN/END/ERROR probes to intermingle.
// But that's OK - they're always treversed with a nested
// "if (type==FOO)" conditional.
return a->priority < b->priority;
}
// No assertion need be emitted, since these probes are allowed for
// unprivileged users.
void emit_unprivileged_assertion (translator_output*) {}
void print_dupe_stamp(ostream& o) { print_dupe_stamp_unprivileged (o); }
bool needs_global_locks () { return false; }
// begin/end probes don't need locks around global variables, since
// they aren't run concurrently with any other probes
};
struct be_derived_probe_group: public generic_dpg<be_derived_probe>
{
public:
void emit_module_decls (systemtap_session& s);
void emit_module_init (systemtap_session& s);
void emit_module_exit (systemtap_session& s);
};
struct be_builder: public derived_probe_builder
{
be_t type;
be_builder(be_t t) : type(t) {}
virtual void build(systemtap_session &,
probe * base,
probe_point * location,
literal_map_t const & parameters,
vector<derived_probe *> & finished_results)
{
int64_t priority;
if ((type == BEGIN && !get_param(parameters, TOK_BEGIN, priority)) ||
(type == END && !get_param(parameters, TOK_END, priority)) ||
(type == ERROR && !get_param(parameters, TOK_ERROR, priority)))
priority = 0;
finished_results.push_back
(new be_derived_probe(base, location, type, priority));
}
};
void
be_derived_probe::join_group (systemtap_session& s)
{
if (! s.be_derived_probes)
s.be_derived_probes = new be_derived_probe_group ();
s.be_derived_probes->enroll (this);
}
void
be_derived_probe_group::emit_module_decls (systemtap_session& s)
{
if (probes.empty()) return;
map<be_t, const char *> states;
states[BEGIN] = "STAP_SESSION_STARTING";
states[END] = "STAP_SESSION_STOPPING";
states[ERROR] = "STAP_SESSION_ERROR";
s.op->newline() << "/* ---- begin/end/error probes ---- */";
// NB: We emit the table in sorted order here, so we don't have to
// store the priority numbers as integers and sort at run time.
sort(probes.begin(), probes.end(), be_derived_probe::comp);
s.op->newline() << "static struct stap_be_probe {";
s.op->newline(1) << "void (*ph)(struct context*);";
s.op->newline() << "const char* pp;";
s.op->newline() << "int state, type;";
s.op->newline(-1) << "} stap_be_probes[] = {";
s.op->indent(1);
for (unsigned i=0; i < probes.size(); i++)
{
s.op->newline () << "{";
s.op->line() << " .pp="
<< lex_cast_qstring (*probes[i]->sole_location()) << ",";
s.op->line() << " .ph=&" << probes[i]->name << ",";
s.op->line() << " .state=" << states[probes[i]->type] << ",";
s.op->line() << " .type=" << probes[i]->type;
s.op->line() << " },";
}
s.op->newline(-1) << "};";
s.op->newline() << "static void enter_be_probe (struct stap_be_probe *stp) {";
s.op->indent(1);
common_probe_entryfn_prologue (s.op, "stp->state", "stp->pp", false);
s.op->newline() << "(*stp->ph) (c);";
common_probe_entryfn_epilogue (s.op, false);
s.op->newline(-1) << "}";
}
void
be_derived_probe_group::emit_module_init (systemtap_session& s)
{
if (probes.empty()) return;
s.op->newline() << "for (i=0; i<" << probes.size() << "; i++) {";
s.op->newline(1) << "struct stap_be_probe* stp = & stap_be_probes [i];";
s.op->newline() << "if (stp->type == " << BEGIN << ")";
s.op->newline(1) << "enter_be_probe (stp); /* rc = 0 */";
// NB: begin probes that cause errors do not constitute registration
// failures. An error message will probably get printed and if
// MAXERRORS was left at 1, we'll get an stp_exit. The
// error-handling probes will be run during the ordinary
// unregistration phase.
s.op->newline(-2) << "}";
}
void
be_derived_probe_group::emit_module_exit (systemtap_session& s)
{
if (probes.empty()) return;
s.op->newline() << "for (i=0; i<" << probes.size() << "; i++) {";
s.op->newline(1) << "struct stap_be_probe* stp = & stap_be_probes [i];";
s.op->newline() << "if (stp->type == " << END << ")";
s.op->newline(1) << "enter_be_probe (stp);";
s.op->newline(-2) << "}";
s.op->newline() << "for (i=0; i<" << probes.size() << "; i++) {";
s.op->newline(1) << "struct stap_be_probe* stp = & stap_be_probes [i];";
s.op->newline() << "if (stp->type == " << ERROR << ")";
s.op->newline(1) << "enter_be_probe (stp);";
s.op->newline(-2) << "}";
}
// ------------------------------------------------------------------------
// never probes are never run
// ------------------------------------------------------------------------
struct never_derived_probe: public derived_probe
{
never_derived_probe (probe* p): derived_probe (p) {}
never_derived_probe (probe* p, probe_point* l): derived_probe (p, l) {}
void join_group (systemtap_session&) { /* thus no probe_group */ }
void emit_unprivileged_assertion (translator_output*) {}
void print_dupe_stamp(ostream& o) { print_dupe_stamp_unprivileged (o); }
};
struct never_builder: public derived_probe_builder
{
never_builder() {}
virtual void build(systemtap_session &,
probe * base,
probe_point * location,
literal_map_t const &,
vector<derived_probe *> & finished_results)
{
finished_results.push_back(new never_derived_probe(base, location));
}
};
// ------------------------------------------------------------------------
// unified registration for begin/end/error/never
// ------------------------------------------------------------------------
void
register_tapset_been(systemtap_session& s)
{
match_node* root = s.pattern_root;
root->bind(TOK_BEGIN)
->bind_unprivileged()
->bind(new be_builder(BEGIN));
root->bind_num(TOK_BEGIN)
->bind_unprivileged()
->bind(new be_builder(BEGIN));
root->bind(TOK_END)
->bind_unprivileged()
->bind(new be_builder(END));
root->bind_num(TOK_END)
->bind_unprivileged()
->bind(new be_builder(END));
root->bind(TOK_ERROR)
->bind_unprivileged()
->bind(new be_builder(ERROR));
root->bind_num(TOK_ERROR)
->bind_unprivileged()
->bind(new be_builder(ERROR));
root->bind(TOK_NEVER)
->bind_unprivileged()
->bind(new never_builder());
}
/* vim: set sw=2 ts=8 cino=>4,n-2,{2,^-2,t0,(0,u0,w1,M1 : */
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