trace-event-info.c

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/*
 * Copyright (C) 2008,2009, Steven Rostedt <[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; version 2 of the License (not later!)
 *
 * 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 "util.h"
#include <dirent.h>
#include <mntent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <pthread.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdbool.h>
#include <linux/list.h>
#include <linux/kernel.h>

#include "../perf.h"
#include "trace-event.h"
#include "debugfs.h"
#include "evsel.h"

#define VERSION "0.5"

#define TRACE_CTRL  "tracing_on"
#define TRACE       "trace"
#define AVAILABLE   "available_tracers"
#define CURRENT     "current_tracer"
#define ITER_CTRL   "trace_options"
#define MAX_LATENCY "tracing_max_latency"

unsigned int page_size;

static const char *output_file = "trace.info";
static int output_fd;

struct event_list {
    struct event_list *next;
    const char *event;
};

struct events {
    struct events *sibling;
    struct events *children;
    struct events *next;
    char *name;
};


static void *malloc_or_die(unsigned int size)
{
    void *data;

    data = malloc(size);
    if (!data)
        die("malloc");
    return data;
}

static const char *find_debugfs(void)
{
    const char *path = debugfs_mount(NULL);

    if (!path)
        die("Your kernel not support debugfs filesystem");

    return path;
}

/*
 * Finds the path to the debugfs/tracing
 * Allocates the string and stores it.
 */
static const char *find_tracing_dir(void)
{
    static char *tracing;
    static int tracing_found;
    const char *debugfs;

    if (tracing_found)
        return tracing;

    debugfs = find_debugfs();

    tracing = malloc_or_die(strlen(debugfs) + 9);

    sprintf(tracing, "%s/tracing", debugfs);

    tracing_found = 1;
    return tracing;
}

static char *get_tracing_file(const char *name)
{
    const char *tracing;
    char *file;

    tracing = find_tracing_dir();
    if (!tracing)
        return NULL;

    file = malloc_or_die(strlen(tracing) + strlen(name) + 2);

    sprintf(file, "%s/%s", tracing, name);
    return file;
}

static void put_tracing_file(char *file)
{
    free(file);
}

static ssize_t calc_data_size;

static ssize_t write_or_die(const void *buf, size_t len)
{
    int ret;

    if (calc_data_size) {
        calc_data_size += len;
        return len;
    }

    ret = write(output_fd, buf, len);
    if (ret < 0)
        die("writing to '%s'", output_file);

    return ret;
}

int bigendian(void)
{
    unsigned char str[] = { 0x1, 0x2, 0x3, 0x4, 0x0, 0x0, 0x0, 0x0};
    unsigned int *ptr;

    ptr = (unsigned int *)(void *)str;
    return *ptr == 0x01020304;
}

/* unfortunately, you can not stat debugfs or proc files for size */
static void record_file(const char *file, size_t hdr_sz)
{
    unsigned long long size = 0;
    char buf[BUFSIZ], *sizep;
    off_t hdr_pos = lseek(output_fd, 0, SEEK_CUR);
    int r, fd;

    fd = open(file, O_RDONLY);
    if (fd < 0)
        die("Can't read '%s'", file);

    /* put in zeros for file size, then fill true size later */
    if (hdr_sz)
        write_or_die(&size, hdr_sz);

    do {
        r = read(fd, buf, BUFSIZ);
        if (r > 0) {
            size += r;
            write_or_die(buf, r);
        }
    } while (r > 0);
    close(fd);

    /* ugh, handle big-endian hdr_size == 4 */
    sizep = (char*)&size;
    if (bigendian())
        sizep += sizeof(u64) - hdr_sz;

    if (hdr_sz && pwrite(output_fd, sizep, hdr_sz, hdr_pos) < 0)
        die("writing to %s", output_file);
}

static void read_header_files(void)
{
    char *path;
    struct stat st;

    path = get_tracing_file("events/header_page");
    if (stat(path, &st) < 0)
        die("can't read '%s'", path);

    write_or_die("header_page", 12);
    record_file(path, 8);
    put_tracing_file(path);

    path = get_tracing_file("events/header_event");
    if (stat(path, &st) < 0)
        die("can't read '%s'", path);

    write_or_die("header_event", 13);
    record_file(path, 8);
    put_tracing_file(path);
}

static bool name_in_tp_list(char *sys, struct tracepoint_path *tps)
{
    while (tps) {
        if (!strcmp(sys, tps->name))
            return true;
        tps = tps->next;
    }

    return false;
}

static void copy_event_system(const char *sys, struct tracepoint_path *tps)
{
    struct dirent *dent;
    struct stat st;
    char *format;
    DIR *dir;
    int count = 0;
    int ret;

    dir = opendir(sys);
    if (!dir)
        die("can't read directory '%s'", sys);

    while ((dent = readdir(dir))) {
        if (dent->d_type != DT_DIR ||
            strcmp(dent->d_name, ".") == 0 ||
            strcmp(dent->d_name, "..") == 0 ||
            !name_in_tp_list(dent->d_name, tps))
            continue;
        format = malloc_or_die(strlen(sys) + strlen(dent->d_name) + 10);
        sprintf(format, "%s/%s/format", sys, dent->d_name);
        ret = stat(format, &st);
        free(format);
        if (ret < 0)
            continue;
        count++;
    }

    write_or_die(&count, 4);

    rewinddir(dir);
    while ((dent = readdir(dir))) {
        if (dent->d_type != DT_DIR ||
            strcmp(dent->d_name, ".") == 0 ||
            strcmp(dent->d_name, "..") == 0 ||
            !name_in_tp_list(dent->d_name, tps))
            continue;
        format = malloc_or_die(strlen(sys) + strlen(dent->d_name) + 10);
        sprintf(format, "%s/%s/format", sys, dent->d_name);
        ret = stat(format, &st);

        if (ret >= 0)
            record_file(format, 8);

        free(format);
    }
    closedir(dir);
}

static void read_ftrace_files(struct tracepoint_path *tps)
{
    char *path;

    path = get_tracing_file("events/ftrace");

    copy_event_system(path, tps);

    put_tracing_file(path);
}

static bool system_in_tp_list(char *sys, struct tracepoint_path *tps)
{
    while (tps) {
        if (!strcmp(sys, tps->system))
            return true;
        tps = tps->next;
    }

    return false;
}

static void read_event_files(struct tracepoint_path *tps)
{
    struct dirent *dent;
    struct stat st;
    char *path;
    char *sys;
    DIR *dir;
    int count = 0;
    int ret;

    path = get_tracing_file("events");

    dir = opendir(path);
    if (!dir)
        die("can't read directory '%s'", path);

    while ((dent = readdir(dir))) {
        if (dent->d_type != DT_DIR ||
            strcmp(dent->d_name, ".") == 0 ||
            strcmp(dent->d_name, "..") == 0 ||
            strcmp(dent->d_name, "ftrace") == 0 ||
            !system_in_tp_list(dent->d_name, tps))
            continue;
        count++;
    }

    write_or_die(&count, 4);

    rewinddir(dir);
    while ((dent = readdir(dir))) {
        if (dent->d_type != DT_DIR ||
            strcmp(dent->d_name, ".") == 0 ||
            strcmp(dent->d_name, "..") == 0 ||
            strcmp(dent->d_name, "ftrace") == 0 ||
            !system_in_tp_list(dent->d_name, tps))
            continue;
        sys = malloc_or_die(strlen(path) + strlen(dent->d_name) + 2);
        sprintf(sys, "%s/%s", path, dent->d_name);
        ret = stat(sys, &st);
        if (ret >= 0) {
            write_or_die(dent->d_name, strlen(dent->d_name) + 1);
            copy_event_system(sys, tps);
        }
        free(sys);
    }

    closedir(dir);
    put_tracing_file(path);
}

static void read_proc_kallsyms(void)
{
    unsigned int size;
    const char *path = "/proc/kallsyms";
    struct stat st;
    int ret;

    ret = stat(path, &st);
    if (ret < 0) {
        /* not found */
        size = 0;
        write_or_die(&size, 4);
        return;
    }
    record_file(path, 4);
}

static void read_ftrace_printk(void)
{
    unsigned int size;
    char *path;
    struct stat st;
    int ret;

    path = get_tracing_file("printk_formats");
    ret = stat(path, &st);
    if (ret < 0) {
        /* not found */
        size = 0;
        write_or_die(&size, 4);
        goto out;
    }
    record_file(path, 4);

out:
    put_tracing_file(path);
}

static struct tracepoint_path *
get_tracepoints_path(struct list_head *pattrs)
{
    struct tracepoint_path path, *ppath = &path;
    struct perf_evsel *pos;
    int nr_tracepoints = 0;

    list_for_each_entry(pos, pattrs, node) {
        if (pos->attr.type != PERF_TYPE_TRACEPOINT)
            continue;
        ++nr_tracepoints;
        ppath->next = tracepoint_id_to_path(pos->attr.config);
        if (!ppath->next)
            die("%s\n", "No memory to alloc tracepoints list");
        ppath = ppath->next;
    }

    return nr_tracepoints > 0 ? path.next : NULL;
}

static void
put_tracepoints_path(struct tracepoint_path *tps)
{
    while (tps) {
        struct tracepoint_path *t = tps;

        tps = tps->next;
        free(t->name);
        free(t->system);
        free(t);
    }
}

bool have_tracepoints(struct list_head *pattrs)
{
    struct perf_evsel *pos;

    list_for_each_entry(pos, pattrs, node)
        if (pos->attr.type == PERF_TYPE_TRACEPOINT)
            return true;

    return false;
}

static void tracing_data_header(void)
{
    char buf[20];

    /* just guessing this is someone's birthday.. ;) */
    buf[0] = 23;
    buf[1] = 8;
    buf[2] = 68;
    memcpy(buf + 3, "tracing", 7);

    write_or_die(buf, 10);

    write_or_die(VERSION, strlen(VERSION) + 1);

    /* save endian */
    if (bigendian())
        buf[0] = 1;
    else
        buf[0] = 0;

    read_trace_init(buf[0], buf[0]);

    write_or_die(buf, 1);

    /* save size of long */
    buf[0] = sizeof(long);
    write_or_die(buf, 1);

    /* save page_size */
    page_size = sysconf(_SC_PAGESIZE);
    write_or_die(&page_size, 4);
}

struct tracing_data *tracing_data_get(struct list_head *pattrs,
                      int fd, bool temp)
{
    struct tracepoint_path *tps;
    struct tracing_data *tdata;

    output_fd = fd;

    tps = get_tracepoints_path(pattrs);
    if (!tps)
        return NULL;

    tdata = malloc_or_die(sizeof(*tdata));
    tdata->temp = temp;
    tdata->size = 0;

    if (temp) {
        int temp_fd;

        snprintf(tdata->temp_file, sizeof(tdata->temp_file),
             "/tmp/perf-XXXXXX");
        if (!mkstemp(tdata->temp_file))
            die("Can't make temp file");

        temp_fd = open(tdata->temp_file, O_RDWR);
        if (temp_fd < 0)
            die("Can't read '%s'", tdata->temp_file);

        /*
         * Set the temp file the default output, so all the
         * tracing data are stored into it.
         */
        output_fd = temp_fd;
    }

    tracing_data_header();
    read_header_files();
    read_ftrace_files(tps);
    read_event_files(tps);
    read_proc_kallsyms();
    read_ftrace_printk();

    /*
     * All tracing data are stored by now, we can restore
     * the default output file in case we used temp file.
     */
    if (temp) {
        tdata->size = lseek(output_fd, 0, SEEK_CUR);
        close(output_fd);
        output_fd = fd;
    }

    put_tracepoints_path(tps);
    return tdata;
}

void tracing_data_put(struct tracing_data *tdata)
{
    if (tdata->temp) {
        record_file(tdata->temp_file, 0);
        unlink(tdata->temp_file);
    }

    free(tdata);
}

int read_tracing_data(int fd, struct list_head *pattrs)
{
    struct tracing_data *tdata;

    /*
     * We work over the real file, so we can write data
     * directly, no temp file is needed.
     */
    tdata = tracing_data_get(pattrs, fd, false);
    if (!tdata)
        return -ENOMEM;

    tracing_data_put(tdata);
    return 0;
}