trace-event-read.c

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/*
 * Copyright (C) 2009, Steven Rostedt <srostedt@redhat.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * 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 <dirent.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 <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

#include "../perf.h"
#include "util.h"
#include "trace-event.h"
#include "debug.h"

static int input_fd;

static ssize_t trace_data_size;
static bool repipe;

static int __do_read(int fd, void *buf, int size)
{
    int rsize = size;

    while (size) {
        int ret = read(fd, buf, size);

        if (ret <= 0)
            return -1;

        if (repipe) {
            int retw = write(STDOUT_FILENO, buf, ret);

            if (retw <= 0 || retw != ret) {
                pr_debug("repiping input file");
                return -1;
            }
        }

        size -= ret;
        buf += ret;
    }

    return rsize;
}

static int do_read(void *data, int size)
{
    int r;

    r = __do_read(input_fd, data, size);
    if (r <= 0) {
        pr_debug("reading input file (size expected=%d received=%d)",
             size, r);
        return -1;
    }

    trace_data_size += r;

    return r;
}

/* If it fails, the next read will report it */
static void skip(int size)
{
    char buf[BUFSIZ];
    int r;

    while (size) {
        r = size > BUFSIZ ? BUFSIZ : size;
        do_read(buf, r);
        size -= r;
    };
}

static unsigned int read4(struct pevent *pevent)
{
    unsigned int data;

    if (do_read(&data, 4) < 0)
        return 0;
    return __data2host4(pevent, data);
}

static unsigned long long read8(struct pevent *pevent)
{
    unsigned long long data;

    if (do_read(&data, 8) < 0)
        return 0;
    return __data2host8(pevent, data);
}

static char *read_string(void)
{
    char buf[BUFSIZ];
    char *str = NULL;
    int size = 0;
    off_t r;
    char c;

    for (;;) {
        r = read(input_fd, &c, 1);
        if (r < 0) {
            pr_debug("reading input file");
            goto out;
        }

        if (!r) {
            pr_debug("no data");
            goto out;
        }

        if (repipe) {
            int retw = write(STDOUT_FILENO, &c, 1);

            if (retw <= 0 || retw != r) {
                pr_debug("repiping input file string");
                goto out;
            }
        }

        buf[size++] = c;

        if (!c)
            break;
    }

    trace_data_size += size;

    str = malloc(size);
    if (str)
        memcpy(str, buf, size);
out:
    return str;
}

static int read_proc_kallsyms(struct pevent *pevent)
{
    unsigned int size;

    size = read4(pevent);
    if (!size)
        return 0;
    /*
     * Just skip it, now that we configure libtraceevent to use the
     * tools/perf/ symbol resolver.
     *
     * We need to skip it so that we can continue parsing old perf.data
     * files, that contains this /proc/kallsyms payload.
     *
     * Newer perf.data files will have just the 4-bytes zeros "kallsyms
     * payload", so that older tools can continue reading it and interpret
     * it as "no kallsyms payload is present".
     */
    lseek(input_fd, size, SEEK_CUR);
    trace_data_size += size;
    return 0;
}

static int read_ftrace_printk(struct pevent *pevent)
{
    unsigned int size;
    char *buf;

    /* it can have 0 size */
    size = read4(pevent);
    if (!size)
        return 0;

    buf = malloc(size + 1);
    if (buf == NULL)
        return -1;

    if (do_read(buf, size) < 0) {
        free(buf);
        return -1;
    }

    buf[size] = '\0';

    parse_ftrace_printk(pevent, buf, size);

    free(buf);
    return 0;
}

static int read_header_files(struct pevent *pevent)
{
    unsigned long long size;
    char *header_page;
    char buf[BUFSIZ];
    int ret = 0;

    if (do_read(buf, 12) < 0)
        return -1;

    if (memcmp(buf, "header_page", 12) != 0) {
        pr_debug("did not read header page");
        return -1;
    }

    size = read8(pevent);

    header_page = malloc(size);
    if (header_page == NULL)
        return -1;

    if (do_read(header_page, size) < 0) {
        pr_debug("did not read header page");
        free(header_page);
        return -1;
    }

    if (!pevent_parse_header_page(pevent, header_page, size,
                      pevent_get_long_size(pevent))) {
        /*
         * The commit field in the page is of type long,
         * use that instead, since it represents the kernel.
         */
        pevent_set_long_size(pevent, pevent->header_page_size_size);
    }
    free(header_page);

    if (do_read(buf, 13) < 0)
        return -1;

    if (memcmp(buf, "header_event", 13) != 0) {
        pr_debug("did not read header event");
        return -1;
    }

    size = read8(pevent);
    skip(size);

    return ret;
}

static int read_ftrace_file(struct pevent *pevent, unsigned long long size)
{
    int ret;
    char *buf;

    buf = malloc(size);
    if (buf == NULL) {
        pr_debug("memory allocation failure\n");
        return -1;
    }

    ret = do_read(buf, size);
    if (ret < 0) {
        pr_debug("error reading ftrace file.\n");
        goto out;
    }

    ret = parse_ftrace_file(pevent, buf, size);
    if (ret < 0)
        pr_debug("error parsing ftrace file.\n");
out:
    free(buf);
    return ret;
}

static int read_event_file(struct pevent *pevent, char *sys,
                unsigned long long size)
{
    int ret;
    char *buf;

    buf = malloc(size);
    if (buf == NULL) {
        pr_debug("memory allocation failure\n");
        return -1;
    }

    ret = do_read(buf, size);
    if (ret < 0) {
        free(buf);
        goto out;
    }

    ret = parse_event_file(pevent, buf, size, sys);
    if (ret < 0)
        pr_debug("error parsing event file.\n");
out:
    free(buf);
    return ret;
}

static int read_ftrace_files(struct pevent *pevent)
{
    unsigned long long size;
    int count;
    int i;
    int ret;

    count = read4(pevent);

    for (i = 0; i < count; i++) {
        size = read8(pevent);
        ret = read_ftrace_file(pevent, size);
        if (ret)
            return ret;
    }
    return 0;
}

static int read_event_files(struct pevent *pevent)
{
    unsigned long long size;
    char *sys;
    int systems;
    int count;
    int i,x;
    int ret;

    systems = read4(pevent);

    for (i = 0; i < systems; i++) {
        sys = read_string();
        if (sys == NULL)
            return -1;

        count = read4(pevent);

        for (x=0; x < count; x++) {
            size = read8(pevent);
            ret = read_event_file(pevent, sys, size);
            if (ret)
                return ret;
        }
    }
    return 0;
}

static int read_saved_cmdline(struct pevent *pevent)
{
    unsigned long long size;
    char *buf;
    int ret;

    /* it can have 0 size */
    size = read8(pevent);
    if (!size)
        return 0;

    buf = malloc(size + 1);
    if (buf == NULL) {
        pr_debug("memory allocation failure\n");
        return -1;
    }

    ret = do_read(buf, size);
    if (ret < 0) {
        pr_debug("error reading saved cmdlines\n");
        goto out;
    }

    parse_saved_cmdline(pevent, buf, size);
    ret = 0;
out:
    free(buf);
    return ret;
}

ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
{
    char buf[BUFSIZ];
    char test[] = { 23, 8, 68 };
    char *version;
    int show_version = 0;
    int show_funcs = 0;
    int show_printk = 0;
    ssize_t size = -1;
    int file_bigendian;
    int host_bigendian;
    int file_long_size;
    int file_page_size;
    struct pevent *pevent = NULL;
    int err;

    repipe = __repipe;
    input_fd = fd;

    if (do_read(buf, 3) < 0)
        return -1;
    if (memcmp(buf, test, 3) != 0) {
        pr_debug("no trace data in the file");
        return -1;
    }

    if (do_read(buf, 7) < 0)
        return -1;
    if (memcmp(buf, "tracing", 7) != 0) {
        pr_debug("not a trace file (missing 'tracing' tag)");
        return -1;
    }

    version = read_string();
    if (version == NULL)
        return -1;
    if (show_version)
        printf("version = %s\n", version);

    if (do_read(buf, 1) < 0) {
        free(version);
        return -1;
    }
    file_bigendian = buf[0];
    host_bigendian = bigendian();

    if (trace_event__init(tevent)) {
        pr_debug("trace_event__init failed");
        goto out;
    }

    pevent = tevent->pevent;

    pevent_set_flag(pevent, PEVENT_NSEC_OUTPUT);
    pevent_set_file_bigendian(pevent, file_bigendian);
    pevent_set_host_bigendian(pevent, host_bigendian);

    if (do_read(buf, 1) < 0)
        goto out;
    file_long_size = buf[0];

    file_page_size = read4(pevent);
    if (!file_page_size)
        goto out;

    pevent_set_long_size(pevent, file_long_size);
    pevent_set_page_size(pevent, file_page_size);

    err = read_header_files(pevent);
    if (err)
        goto out;
    err = read_ftrace_files(pevent);
    if (err)
        goto out;
    err = read_event_files(pevent);
    if (err)
        goto out;
    err = read_proc_kallsyms(pevent);
    if (err)
        goto out;
    err = read_ftrace_printk(pevent);
    if (err)
        goto out;
    if (atof(version) >= 0.6) {
        err = read_saved_cmdline(pevent);
        if (err)
            goto out;
    }

    size = trace_data_size;
    repipe = false;

    if (show_funcs) {
        pevent_print_funcs(pevent);
    } else if (show_printk) {
        pevent_print_printk(pevent);
    }

    pevent = NULL;

out:
    if (pevent)
        trace_event__cleanup(tevent);
    free(version);
    return size;
}