trace-event-python.c

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/*
 * trace-event-python.  Feed trace events to an embedded Python interpreter.
 *
 * Copyright (C) 2010 Tom Zanussi <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <Python.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include "../../perf.h"
#include "../evsel.h"
#include "../util.h"
#include "../event.h"
#include "../thread.h"
#include "../trace-event.h"
#include "../evsel.h"

PyMODINIT_FUNC initperf_trace_context(void);

#define FTRACE_MAX_EVENT                \
    ((1 << (sizeof(unsigned short) * 8)) - 1)

struct event_format *events[FTRACE_MAX_EVENT];

#define MAX_FIELDS  64
#define N_COMMON_FIELDS 7

extern struct scripting_context *scripting_context;

static char *cur_field_name;
static int zero_flag_atom;

static PyObject *main_module, *main_dict;

static void handler_call_die(const char *handler_name)
{
    PyErr_Print();
    Py_FatalError("problem in Python trace event handler");
}

static void define_value(enum print_arg_type field_type,
             const char *ev_name,
             const char *field_name,
             const char *field_value,
             const char *field_str)
{
    const char *handler_name = "define_flag_value";
    PyObject *handler, *t, *retval;
    unsigned long long value;
    unsigned n = 0;

    if (field_type == PRINT_SYMBOL)
        handler_name = "define_symbolic_value";

    t = PyTuple_New(4);
    if (!t)
        Py_FatalError("couldn't create Python tuple");

    value = eval_flag(field_value);

    PyTuple_SetItem(t, n++, PyString_FromString(ev_name));
    PyTuple_SetItem(t, n++, PyString_FromString(field_name));
    PyTuple_SetItem(t, n++, PyInt_FromLong(value));
    PyTuple_SetItem(t, n++, PyString_FromString(field_str));

    handler = PyDict_GetItemString(main_dict, handler_name);
    if (handler && PyCallable_Check(handler)) {
        retval = PyObject_CallObject(handler, t);
        if (retval == NULL)
            handler_call_die(handler_name);
    }

    Py_DECREF(t);
}

static void define_values(enum print_arg_type field_type,
              struct print_flag_sym *field,
              const char *ev_name,
              const char *field_name)
{
    define_value(field_type, ev_name, field_name, field->value,
             field->str);

    if (field->next)
        define_values(field_type, field->next, ev_name, field_name);
}

static void define_field(enum print_arg_type field_type,
             const char *ev_name,
             const char *field_name,
             const char *delim)
{
    const char *handler_name = "define_flag_field";
    PyObject *handler, *t, *retval;
    unsigned n = 0;

    if (field_type == PRINT_SYMBOL)
        handler_name = "define_symbolic_field";

    if (field_type == PRINT_FLAGS)
        t = PyTuple_New(3);
    else
        t = PyTuple_New(2);
    if (!t)
        Py_FatalError("couldn't create Python tuple");

    PyTuple_SetItem(t, n++, PyString_FromString(ev_name));
    PyTuple_SetItem(t, n++, PyString_FromString(field_name));
    if (field_type == PRINT_FLAGS)
        PyTuple_SetItem(t, n++, PyString_FromString(delim));

    handler = PyDict_GetItemString(main_dict, handler_name);
    if (handler && PyCallable_Check(handler)) {
        retval = PyObject_CallObject(handler, t);
        if (retval == NULL)
            handler_call_die(handler_name);
    }

    Py_DECREF(t);
}

static void define_event_symbols(struct event_format *event,
                 const char *ev_name,
                 struct print_arg *args)
{
    switch (args->type) {
    case PRINT_NULL:
        break;
    case PRINT_ATOM:
        define_value(PRINT_FLAGS, ev_name, cur_field_name, "0",
                 args->atom.atom);
        zero_flag_atom = 0;
        break;
    case PRINT_FIELD:
        if (cur_field_name)
            free(cur_field_name);
        cur_field_name = strdup(args->field.name);
        break;
    case PRINT_FLAGS:
        define_event_symbols(event, ev_name, args->flags.field);
        define_field(PRINT_FLAGS, ev_name, cur_field_name,
                 args->flags.delim);
        define_values(PRINT_FLAGS, args->flags.flags, ev_name,
                  cur_field_name);
        break;
    case PRINT_SYMBOL:
        define_event_symbols(event, ev_name, args->symbol.field);
        define_field(PRINT_SYMBOL, ev_name, cur_field_name, NULL);
        define_values(PRINT_SYMBOL, args->symbol.symbols, ev_name,
                  cur_field_name);
        break;
    case PRINT_HEX:
        define_event_symbols(event, ev_name, args->hex.field);
        define_event_symbols(event, ev_name, args->hex.size);
        break;
    case PRINT_STRING:
        break;
    case PRINT_TYPE:
        define_event_symbols(event, ev_name, args->typecast.item);
        break;
    case PRINT_OP:
        if (strcmp(args->op.op, ":") == 0)
            zero_flag_atom = 1;
        define_event_symbols(event, ev_name, args->op.left);
        define_event_symbols(event, ev_name, args->op.right);
        break;
    default:
        /* gcc warns for these? */
    case PRINT_BSTRING:
    case PRINT_DYNAMIC_ARRAY:
    case PRINT_FUNC:
        /* we should warn... */
        return;
    }

    if (args->next)
        define_event_symbols(event, ev_name, args->next);
}

static inline struct event_format *find_cache_event(struct perf_evsel *evsel)
{
    static char ev_name[256];
    struct event_format *event;
    int type = evsel->attr.config;

    /*
     * XXX: Do we really need to cache this since now we have evsel->tp_format
     * cached already? Need to re-read this "cache" routine that as well calls
     * define_event_symbols() :-\
     */
    if (events[type])
        return events[type];

    events[type] = event = evsel->tp_format;
    if (!event)
        return NULL;

    sprintf(ev_name, "%s__%s", event->system, event->name);

    define_event_symbols(event, ev_name, event->print_fmt.args);

    return event;
}

static void python_process_tracepoint(union perf_event *perf_event
                      __maybe_unused,
                 struct perf_sample *sample,
                 struct perf_evsel *evsel,
                 struct machine *machine __maybe_unused,
                 struct addr_location *al)
{
    PyObject *handler, *retval, *context, *t, *obj, *dict = NULL;
    static char handler_name[256];
    struct format_field *field;
    unsigned long long val;
    unsigned long s, ns;
    struct event_format *event;
    unsigned n = 0;
    int pid;
    int cpu = sample->cpu;
    void *data = sample->raw_data;
    unsigned long long nsecs = sample->time;
    struct thread *thread = al->thread;
    char *comm = thread->comm;

    t = PyTuple_New(MAX_FIELDS);
    if (!t)
        Py_FatalError("couldn't create Python tuple");

    event = find_cache_event(evsel);
    if (!event)
        die("ug! no event found for type %d", (int)evsel->attr.config);

    pid = raw_field_value(event, "common_pid", data);

    sprintf(handler_name, "%s__%s", event->system, event->name);

    handler = PyDict_GetItemString(main_dict, handler_name);
    if (handler && !PyCallable_Check(handler))
        handler = NULL;
    if (!handler) {
        dict = PyDict_New();
        if (!dict)
            Py_FatalError("couldn't create Python dict");
    }
    s = nsecs / NSECS_PER_SEC;
    ns = nsecs - s * NSECS_PER_SEC;

    scripting_context->event_data = data;

    context = PyCObject_FromVoidPtr(scripting_context, NULL);

    PyTuple_SetItem(t, n++, PyString_FromString(handler_name));
    PyTuple_SetItem(t, n++, context);

    if (handler) {
        PyTuple_SetItem(t, n++, PyInt_FromLong(cpu));
        PyTuple_SetItem(t, n++, PyInt_FromLong(s));
        PyTuple_SetItem(t, n++, PyInt_FromLong(ns));
        PyTuple_SetItem(t, n++, PyInt_FromLong(pid));
        PyTuple_SetItem(t, n++, PyString_FromString(comm));
    } else {
        PyDict_SetItemString(dict, "common_cpu", PyInt_FromLong(cpu));
        PyDict_SetItemString(dict, "common_s", PyInt_FromLong(s));
        PyDict_SetItemString(dict, "common_ns", PyInt_FromLong(ns));
        PyDict_SetItemString(dict, "common_pid", PyInt_FromLong(pid));
        PyDict_SetItemString(dict, "common_comm", PyString_FromString(comm));
    }
    for (field = event->format.fields; field; field = field->next) {
        if (field->flags & FIELD_IS_STRING) {
            int offset;
            if (field->flags & FIELD_IS_DYNAMIC) {
                offset = *(int *)(data + field->offset);
                offset &= 0xffff;
            } else
                offset = field->offset;
            obj = PyString_FromString((char *)data + offset);
        } else { /* FIELD_IS_NUMERIC */
            val = read_size(event, data + field->offset,
                    field->size);
            if (field->flags & FIELD_IS_SIGNED) {
                if ((long long)val >= LONG_MIN &&
                    (long long)val <= LONG_MAX)
                    obj = PyInt_FromLong(val);
                else
                    obj = PyLong_FromLongLong(val);
            } else {
                if (val <= LONG_MAX)
                    obj = PyInt_FromLong(val);
                else
                    obj = PyLong_FromUnsignedLongLong(val);
            }
        }
        if (handler)
            PyTuple_SetItem(t, n++, obj);
        else
            PyDict_SetItemString(dict, field->name, obj);

    }
    if (!handler)
        PyTuple_SetItem(t, n++, dict);

    if (_PyTuple_Resize(&t, n) == -1)
        Py_FatalError("error resizing Python tuple");

    if (handler) {
        retval = PyObject_CallObject(handler, t);
        if (retval == NULL)
            handler_call_die(handler_name);
    } else {
        handler = PyDict_GetItemString(main_dict, "trace_unhandled");
        if (handler && PyCallable_Check(handler)) {

            retval = PyObject_CallObject(handler, t);
            if (retval == NULL)
                handler_call_die("trace_unhandled");
        }
        Py_DECREF(dict);
    }

    Py_DECREF(t);
}

static void python_process_general_event(union perf_event *perf_event
                     __maybe_unused,
                     struct perf_sample *sample,
                     struct perf_evsel *evsel,
                     struct machine *machine __maybe_unused,
                     struct addr_location *al)
{
    PyObject *handler, *retval, *t, *dict;
    static char handler_name[64];
    unsigned n = 0;
    struct thread *thread = al->thread;

    /*
     * Use the MAX_FIELDS to make the function expandable, though
     * currently there is only one item for the tuple.
     */
    t = PyTuple_New(MAX_FIELDS);
    if (!t)
        Py_FatalError("couldn't create Python tuple");

    dict = PyDict_New();
    if (!dict)
        Py_FatalError("couldn't create Python dictionary");

    snprintf(handler_name, sizeof(handler_name), "%s", "process_event");

    handler = PyDict_GetItemString(main_dict, handler_name);
    if (!handler || !PyCallable_Check(handler))
        goto exit;

    PyDict_SetItemString(dict, "ev_name", PyString_FromString(perf_evsel__name(evsel)));
    PyDict_SetItemString(dict, "attr", PyString_FromStringAndSize(
            (const char *)&evsel->attr, sizeof(evsel->attr)));
    PyDict_SetItemString(dict, "sample", PyString_FromStringAndSize(
            (const char *)sample, sizeof(*sample)));
    PyDict_SetItemString(dict, "raw_buf", PyString_FromStringAndSize(
            (const char *)sample->raw_data, sample->raw_size));
    PyDict_SetItemString(dict, "comm",
            PyString_FromString(thread->comm));
    if (al->map) {
        PyDict_SetItemString(dict, "dso",
            PyString_FromString(al->map->dso->name));
    }
    if (al->sym) {
        PyDict_SetItemString(dict, "symbol",
            PyString_FromString(al->sym->name));
    }

    PyTuple_SetItem(t, n++, dict);
    if (_PyTuple_Resize(&t, n) == -1)
        Py_FatalError("error resizing Python tuple");

    retval = PyObject_CallObject(handler, t);
    if (retval == NULL)
        handler_call_die(handler_name);
exit:
    Py_DECREF(dict);
    Py_DECREF(t);
}

static void python_process_event(union perf_event *perf_event,
                 struct perf_sample *sample,
                 struct perf_evsel *evsel,
                 struct machine *machine,
                 struct addr_location *al)
{
    switch (evsel->attr.type) {
    case PERF_TYPE_TRACEPOINT:
        python_process_tracepoint(perf_event, sample, evsel,
                      machine, al);
        break;
    /* Reserve for future process_hw/sw/raw APIs */
    default:
        python_process_general_event(perf_event, sample, evsel,
                         machine, al);
    }
}

static int run_start_sub(void)
{
    PyObject *handler, *retval;
    int err = 0;

    main_module = PyImport_AddModule("__main__");
    if (main_module == NULL)
        return -1;
    Py_INCREF(main_module);

    main_dict = PyModule_GetDict(main_module);
    if (main_dict == NULL) {
        err = -1;
        goto error;
    }
    Py_INCREF(main_dict);

    handler = PyDict_GetItemString(main_dict, "trace_begin");
    if (handler == NULL || !PyCallable_Check(handler))
        goto out;

    retval = PyObject_CallObject(handler, NULL);
    if (retval == NULL)
        handler_call_die("trace_begin");

    Py_DECREF(retval);
    return err;
error:
    Py_XDECREF(main_dict);
    Py_XDECREF(main_module);
out:
    return err;
}

/*
 * Start trace script
 */
static int python_start_script(const char *script, int argc, const char **argv)
{
    const char **command_line;
    char buf[PATH_MAX];
    int i, err = 0;
    FILE *fp;

    command_line = malloc((argc + 1) * sizeof(const char *));
    command_line[0] = script;
    for (i = 1; i < argc + 1; i++)
        command_line[i] = argv[i - 1];

    Py_Initialize();

    initperf_trace_context();

    PySys_SetArgv(argc + 1, (char **)command_line);

    fp = fopen(script, "r");
    if (!fp) {
        sprintf(buf, "Can't open python script \"%s\"", script);
        perror(buf);
        err = -1;
        goto error;
    }

    err = PyRun_SimpleFile(fp, script);
    if (err) {
        fprintf(stderr, "Error running python script %s\n", script);
        goto error;
    }

    err = run_start_sub();
    if (err) {
        fprintf(stderr, "Error starting python script %s\n", script);
        goto error;
    }

    free(command_line);

    return err;
error:
    Py_Finalize();
    free(command_line);

    return err;
}

/*
 * Stop trace script
 */
static int python_stop_script(void)
{
    PyObject *handler, *retval;
    int err = 0;

    handler = PyDict_GetItemString(main_dict, "trace_end");
    if (handler == NULL || !PyCallable_Check(handler))
        goto out;

    retval = PyObject_CallObject(handler, NULL);
    if (retval == NULL)
        handler_call_die("trace_end");
    else
        Py_DECREF(retval);
out:
    Py_XDECREF(main_dict);
    Py_XDECREF(main_module);
    Py_Finalize();

    return err;
}

static int python_generate_script(struct pevent *pevent, const char *outfile)
{
    struct event_format *event = NULL;
    struct format_field *f;
    char fname[PATH_MAX];
    int not_first, count;
    FILE *ofp;

    sprintf(fname, "%s.py", outfile);
    ofp = fopen(fname, "w");
    if (ofp == NULL) {
        fprintf(stderr, "couldn't open %s\n", fname);
        return -1;
    }
    fprintf(ofp, "# perf script event handlers, "
        "generated by perf script -g python\n");

    fprintf(ofp, "# Licensed under the terms of the GNU GPL"
        " License version 2\n\n");

    fprintf(ofp, "# The common_* event handler fields are the most useful "
        "fields common to\n");

    fprintf(ofp, "# all events.  They don't necessarily correspond to "
        "the 'common_*' fields\n");

    fprintf(ofp, "# in the format files.  Those fields not available as "
        "handler params can\n");

    fprintf(ofp, "# be retrieved using Python functions of the form "
        "common_*(context).\n");

    fprintf(ofp, "# See the perf-trace-python Documentation for the list "
        "of available functions.\n\n");

    fprintf(ofp, "import os\n");
    fprintf(ofp, "import sys\n\n");

    fprintf(ofp, "sys.path.append(os.environ['PERF_EXEC_PATH'] + \\\n");
    fprintf(ofp, "\t'/scripts/python/Perf-Trace-Util/lib/Perf/Trace')\n");
    fprintf(ofp, "\nfrom perf_trace_context import *\n");
    fprintf(ofp, "from Core import *\n\n\n");

    fprintf(ofp, "def trace_begin():\n");
    fprintf(ofp, "\tprint \"in trace_begin\"\n\n");

    fprintf(ofp, "def trace_end():\n");
    fprintf(ofp, "\tprint \"in trace_end\"\n\n");

    while ((event = trace_find_next_event(pevent, event))) {
        fprintf(ofp, "def %s__%s(", event->system, event->name);
        fprintf(ofp, "event_name, ");
        fprintf(ofp, "context, ");
        fprintf(ofp, "common_cpu,\n");
        fprintf(ofp, "\tcommon_secs, ");
        fprintf(ofp, "common_nsecs, ");
        fprintf(ofp, "common_pid, ");
        fprintf(ofp, "common_comm,\n\t");

        not_first = 0;
        count = 0;

        for (f = event->format.fields; f; f = f->next) {
            if (not_first++)
                fprintf(ofp, ", ");
            if (++count % 5 == 0)
                fprintf(ofp, "\n\t");

            fprintf(ofp, "%s", f->name);
        }
        fprintf(ofp, "):\n");

        fprintf(ofp, "\t\tprint_header(event_name, common_cpu, "
            "common_secs, common_nsecs,\n\t\t\t"
            "common_pid, common_comm)\n\n");

        fprintf(ofp, "\t\tprint \"");

        not_first = 0;
        count = 0;

        for (f = event->format.fields; f; f = f->next) {
            if (not_first++)
                fprintf(ofp, ", ");
            if (count && count % 3 == 0) {
                fprintf(ofp, "\" \\\n\t\t\"");
            }
            count++;

            fprintf(ofp, "%s=", f->name);
            if (f->flags & FIELD_IS_STRING ||
                f->flags & FIELD_IS_FLAG ||
                f->flags & FIELD_IS_SYMBOLIC)
                fprintf(ofp, "%%s");
            else if (f->flags & FIELD_IS_SIGNED)
                fprintf(ofp, "%%d");
            else
                fprintf(ofp, "%%u");
        }

        fprintf(ofp, "\\n\" %% \\\n\t\t(");

        not_first = 0;
        count = 0;

        for (f = event->format.fields; f; f = f->next) {
            if (not_first++)
                fprintf(ofp, ", ");

            if (++count % 5 == 0)
                fprintf(ofp, "\n\t\t");

            if (f->flags & FIELD_IS_FLAG) {
                if ((count - 1) % 5 != 0) {
                    fprintf(ofp, "\n\t\t");
                    count = 4;
                }
                fprintf(ofp, "flag_str(\"");
                fprintf(ofp, "%s__%s\", ", event->system,
                    event->name);
                fprintf(ofp, "\"%s\", %s)", f->name,
                    f->name);
            } else if (f->flags & FIELD_IS_SYMBOLIC) {
                if ((count - 1) % 5 != 0) {
                    fprintf(ofp, "\n\t\t");
                    count = 4;
                }
                fprintf(ofp, "symbol_str(\"");
                fprintf(ofp, "%s__%s\", ", event->system,
                    event->name);
                fprintf(ofp, "\"%s\", %s)", f->name,
                    f->name);
            } else
                fprintf(ofp, "%s", f->name);
        }

        fprintf(ofp, "),\n\n");
    }

    fprintf(ofp, "def trace_unhandled(event_name, context, "
        "event_fields_dict):\n");

    fprintf(ofp, "\t\tprint ' '.join(['%%s=%%s'%%(k,str(v))"
        "for k,v in sorted(event_fields_dict.items())])\n\n");

    fprintf(ofp, "def print_header("
        "event_name, cpu, secs, nsecs, pid, comm):\n"
        "\tprint \"%%-20s %%5u %%05u.%%09u %%8u %%-20s \" %% \\\n\t"
        "(event_name, cpu, secs, nsecs, pid, comm),\n");

    fclose(ofp);

    fprintf(stderr, "generated Python script: %s\n", fname);

    return 0;
}

struct scripting_ops python_scripting_ops = {
    .name = "Python",
    .start_script = python_start_script,
    .stop_script = python_stop_script,
    .process_event = python_process_event,
    .generate_script = python_generate_script,
};