/*
 * Copyright (C) 2008,2009, 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
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
#define _GNU_SOURCE
#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 <ctype.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 _STR(x) #x
#define STR(x) _STR(x)
#define MAX_PATH 256

#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 die(const char *fmt, ...)
{
        va_list ap;
        int ret = errno;

        if (errno)
                perror("perf");
        else
                ret = -1;

        va_start(ap, fmt);
        fprintf(stderr, "  ");
        vfprintf(stderr, fmt, ap);
        va_end(ap);

        fprintf(stderr, "\n");
        exit(ret);
}

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;

        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;
}