[lttngtop.git] / src / lttngtop.c

/*
 * Copyright (C) 2013 Julien Desfossez
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License Version 2 as
 * published by the Free Software Foundation;
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#define _GNU_SOURCE
#include <config.h>
#include <stdio.h>
#include <stdint.h>
#include <babeltrace/babeltrace.h>
#include <babeltrace/ctf/events.h>
#include <babeltrace/ctf/callbacks.h>
#include <babeltrace/ctf/iterator.h>
#include <fcntl.h>
#include <pthread.h>
#include <popt.h>
#include <stdlib.h>
#include <ftw.h>
#include <dirent.h>
#include <ctype.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <fts.h>
#include <assert.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <lttng/lttng.h>
#ifdef LTTNGTOP_MMAP_LIVE
#include <lttng/lttngtop-helper.h>
#include <babeltrace/lttngtopmmappacketseek.h>
#include "mmap-live.h"
#endif /* LTTNGTOP_MMAP_LIVE */

#include "lttngtoptypes.h"
#include "cputop.h"
#include "iostreamtop.h"
#include "cursesdisplay.h"
#include "common.h"
#include "network-live.h"

#define NET_URL_PREFIX  "net://"
#define NET4_URL_PREFIX "net4://"
#define NET6_URL_PREFIX "net6://"

#define DEFAULT_FILE_ARRAY_SIZE 1

const char *opt_input_path;
int opt_textdump;
int opt_child;
int opt_begin;

int quit = 0;

struct lttngtop *copy;
pthread_t display_thread;
pthread_t timer_thread;

unsigned long refresh_display = 1 * NSEC_PER_SEC;
unsigned long last_display_update = 0;
unsigned long last_event_ts = 0;

/* list of FDs available for being read with snapshots */
struct bt_mmap_stream_list mmap_list;
GPtrArray *lttng_consumer_stream_array;
int sessiond_metadata, consumerd_metadata;
struct lttng_consumer_local_data *ctx = NULL;
/* list of snapshots currently not consumed */
GPtrArray *available_snapshots;
sem_t metadata_available;
int reload_trace = 0;

uint64_t prev_ts = 0;

enum {
        OPT_NONE = 0,
        OPT_HELP,
        OPT_TEXTDUMP,
        OPT_PID,
        OPT_CHILD,
        OPT_HOSTNAME,
        OPT_RELAY_HOSTNAME,
        OPT_KPROBES,
        OPT_BEGIN,
};

static struct poptOption long_options[] = {
        /* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
        { "help", 'h', POPT_ARG_NONE, NULL, OPT_HELP, NULL, NULL },
        { "textdump", 't', POPT_ARG_NONE, NULL, OPT_TEXTDUMP, NULL, NULL },
        { "child", 'f', POPT_ARG_NONE, NULL, OPT_CHILD, NULL, NULL },
        { "begin", 'b', POPT_ARG_NONE, NULL, OPT_BEGIN, NULL, NULL },
        { "pid", 'p', POPT_ARG_STRING, &opt_tid, OPT_PID, NULL, NULL },
        { "hostname", 'n', POPT_ARG_STRING, &opt_hostname, OPT_HOSTNAME, NULL, NULL },
        { "relay-hostname", 'r', POPT_ARG_STRING, &opt_relay_hostname,
                OPT_RELAY_HOSTNAME, NULL, NULL },
        { "kprobes", 'k', POPT_ARG_STRING, &opt_kprobes, OPT_KPROBES, NULL, NULL },
        { NULL, 0, 0, NULL, 0, NULL, NULL },
};

#ifdef LTTNGTOP_MMAP_LIVE
static void handle_textdump_sigterm(int signal)
{
        quit = 1;
        lttng_destroy_session("test");
}
#endif

void *refresh_thread(void *p)
{
        while (1) {
                if (quit) {
                        sem_post(&pause_sem);
                        sem_post(&timer);
                        sem_post(&end_trace_sem);
                        sem_post(&goodtodisplay);
                        sem_post(&goodtoupdate);
                        pthread_exit(0);
                }
                if (!opt_input_path) {
#ifdef LTTNGTOP_MMAP_LIVE 
                        mmap_live_flush(mmap_list);
#endif
                }
                sem_wait(&pause_sem);
                sem_post(&pause_sem);
                sem_post(&timer);
                sleep(refresh_display/NSEC_PER_SEC);
        }
}

void *ncurses_display(void *p)
{
        unsigned int current_display_index = 0;

        sem_wait(&bootstrap);
        /*
         * Prevent the 1 second delay when we hit ESC
         */
        ESCDELAY = 0;
        init_ncurses();

        while (1) {
                sem_wait(&timer);
                sem_wait(&goodtodisplay);
                sem_wait(&pause_sem);

                if (quit) {
                        sem_post(&pause_sem);
                        sem_post(&timer);
                        reset_ncurses();
                        pthread_exit(0);
                }

                copy = g_ptr_array_index(copies, current_display_index);
                assert(copy);
                display(current_display_index++);

                sem_post(&goodtoupdate);
                sem_post(&pause_sem);
        }
}

void print_fields(struct bt_ctf_event *event)
{
        unsigned int cnt, i;
        const struct bt_definition *const * list;
        const struct bt_declaration *l;
        const struct bt_definition *scope;
        enum ctf_type_id type;
        const char *str;

        scope = bt_ctf_get_top_level_scope(event, BT_EVENT_FIELDS);

        bt_ctf_get_field_list(event, scope, &list, &cnt);
        for (i = 0; i < cnt; i++) {
                if (i != 0)
                        printf(", ");
                printf("%s = ", bt_ctf_field_name(list[i]));
                l = bt_ctf_get_decl_from_def(list[i]);
                type = bt_ctf_field_type(l);
                if (type == CTF_TYPE_INTEGER) {
                        if (bt_ctf_get_int_signedness(l) == 0)
                                printf("%" PRIu64 "", bt_ctf_get_uint64(list[i]));
                        else
                                printf("%" PRId64 "", bt_ctf_get_int64(list[i]));
                } else if (type == CTF_TYPE_STRING) {
                        printf("%s", bt_ctf_get_string(list[i]));
                } else if (type == CTF_TYPE_ARRAY) {
                        str = bt_ctf_get_char_array(list[i]);
                        if (!bt_ctf_field_get_error() && str)
                                printf("%s", str);
                }
        }
}

/*
 * hook on each event to check the timestamp and refresh the display if
 * necessary
 */
enum bt_cb_ret print_timestamp(struct bt_ctf_event *call_data, void *private_data)
{
        unsigned long timestamp;
        uint64_t delta;
        struct tm start;
        uint64_t ts_nsec_start;
        int pid, cpu_id, tid, ret, lookup;
        const struct bt_definition *scope;
        const char *hostname, *procname;
        struct cputime *cpu;
        char *from_syscall = NULL;

        timestamp = bt_ctf_get_timestamp(call_data);

        /* can happen in network live when tracing is idle */
        if (timestamp < last_event_ts)
                goto end_stop;

        last_event_ts = timestamp;

        start = format_timestamp(timestamp);
        ts_nsec_start = timestamp % NSEC_PER_SEC;

        pid = get_context_pid(call_data);
        if (pid == -1ULL && opt_tid) {
                goto error;
        }

        tid = get_context_tid(call_data);
        
        hostname = get_context_hostname(call_data);
        if (opt_child)
                lookup = pid;
        else
                lookup = tid;
        if (opt_tid || opt_hostname || opt_exec_name) {
                if (!lookup_filter_tid_list(lookup)) {
                        /* To display when a process of ours in getting scheduled in */
                        if (strcmp(bt_ctf_event_name(call_data), "sched_switch") == 0) {
                                int next_tid;

                                scope = bt_ctf_get_top_level_scope(call_data,
                                                BT_EVENT_FIELDS);
                                next_tid = bt_ctf_get_int64(bt_ctf_get_field(call_data,
                                                        scope, "_next_tid"));
                                if (bt_ctf_field_get_error()) {
                                        fprintf(stderr, "Missing next_tid field\n");
                                        goto error;
                                }
                                if (!lookup_filter_tid_list(next_tid)) {
                                        goto end;
                                }
                        } else {
                                goto end;
                        }
                }
        }

        cpu_id = get_cpu_id(call_data);
        procname = get_context_comm(call_data);
        if (strncmp(bt_ctf_event_name(call_data), "sys_", 4) == 0) {
                cpu = get_cpu(cpu_id);
                cpu->current_syscall = g_new0(struct syscall, 1);
                cpu->current_syscall->name = strdup(bt_ctf_event_name(call_data));
                cpu->current_syscall->ts_start = timestamp;
        } else if ((strncmp(bt_ctf_event_name(call_data), "exit_syscall", 12)) == 0) {
                struct tm start_ts;

                cpu = get_cpu(cpu_id);
                if (cpu->current_syscall) {
                        delta = timestamp - cpu->current_syscall->ts_start;
                        start_ts = format_timestamp(cpu->current_syscall->ts_start);
                        ret = asprintf(&from_syscall, " [from %02d:%02d:%02d.%09" PRIu64
                                        " (+%" PRIu64 ".%09" PRIu64 ") (cpu %d) %s]\n",
                                        start_ts.tm_hour, start_ts.tm_min, start_ts.tm_sec,
                                        cpu->current_syscall->ts_start % NSEC_PER_SEC,
                                        delta / NSEC_PER_SEC, delta % NSEC_PER_SEC,
                                        cpu_id, cpu->current_syscall->name);
                        if (ret < 0) {
                                goto error;
                        }
                        free(cpu->current_syscall->name);
                        g_free(cpu->current_syscall);
                        cpu->current_syscall = NULL;
                }
        }

        if (prev_ts == 0)
                prev_ts = timestamp;
        delta = timestamp - prev_ts;
        prev_ts = timestamp;

        printf("%02d:%02d:%02d.%09" PRIu64 " (+%" PRIu64 ".%09" PRIu64 ") %s%s"
                        "(cpu %d) [%s (%d/%d)] %s (",
                        start.tm_hour, start.tm_min, start.tm_sec,
                        ts_nsec_start, delta / NSEC_PER_SEC,
                        delta % NSEC_PER_SEC, (hostname) ? hostname : "",
                        (hostname) ? " ": "", cpu_id, procname, pid, tid,
                        bt_ctf_event_name(call_data));
        print_fields(call_data);
        printf(")%s", (from_syscall) ? from_syscall : "\n");

        free(from_syscall);

end:
        return BT_CB_OK;
error:
        return BT_CB_ERROR_STOP;
end_stop:
        return BT_CB_OK_STOP;
}

enum bt_cb_ret handle_kprobes(struct bt_ctf_event *call_data, void *private_data)
{
        int i;
        struct kprobes *kprobe;

        /* for kprobes */
        for (i = 0; i < lttngtop.kprobes_table->len; i++) {
                kprobe = g_ptr_array_index(lttngtop.kprobes_table, i);
                if (strcmp(bt_ctf_event_name(call_data), kprobe->probe_name) == 0) {
                        kprobe->count++;
                }
        }

        return BT_CB_OK;
}

/*
 * hook on each event to check the timestamp and refresh the display if
 * necessary
 */
enum bt_cb_ret check_timestamp(struct bt_ctf_event *call_data, void *private_data)
{
        unsigned long timestamp;

        timestamp = bt_ctf_get_timestamp(call_data);
        if (timestamp == -1ULL)
                goto error;

        /* can happen in network live when tracing is idle */
        if (timestamp < last_event_ts)
                goto end_stop;

        last_event_ts = timestamp;

        if (last_display_update == 0)
                last_display_update = timestamp;

        if (timestamp - last_display_update >= refresh_display) {
                sem_wait(&goodtoupdate);
                g_ptr_array_add(copies, get_copy_lttngtop(last_display_update,
                                        timestamp));
                sem_post(&goodtodisplay);
                sem_post(&bootstrap);
                last_display_update = timestamp;
        }
        return BT_CB_OK;

error:
        fprintf(stderr, "check_timestamp callback error\n");
        return BT_CB_ERROR_STOP;

end_stop:
        return BT_CB_OK_STOP;
}

/*
 * get_perf_counter : get or create and return a perf_counter struct for
 * either a process or a cpu (only one of the 2 parameters mandatory)
 */
struct perfcounter *get_perf_counter(const char *name, struct processtop *proc,
                struct cputime *cpu)
{
        struct perfcounter *ret;
        GHashTable *table;

        if (proc)
                table = proc->perf;
        else if (cpu)
                table = cpu->perf;
        else
                goto error;

        ret = g_hash_table_lookup(table, (gpointer) name);
        if (ret)
                goto end;

        ret = g_new0(struct perfcounter, 1);
        /* by default, make it visible in the UI */
        ret->visible = 1;
        g_hash_table_insert(table, (gpointer) strdup(name), ret);

end:
        return ret;

error:
        return NULL;
}

void update_perf_value(struct processtop *proc, struct cputime *cpu,
                const char *name, int value)
{
        struct perfcounter *cpu_perf, *process_perf;

        cpu_perf = get_perf_counter(name, NULL, cpu);
        if (cpu_perf->count < value) {
                process_perf = get_perf_counter(name, proc, NULL);
                process_perf->count += value - cpu_perf->count;
                cpu_perf->count = value;
        }
}

void extract_perf_counter_scope(const struct bt_ctf_event *event,
                const struct bt_definition *scope,
                struct processtop *proc,
                struct cputime *cpu)
{
        struct bt_definition const * const *list = NULL;
        const struct bt_definition *field;
        unsigned int count;
        struct perfcounter *perfcounter;
        GHashTableIter iter;
        gpointer key;
        int ret;

        if (!scope)
                goto end;

        ret = bt_ctf_get_field_list(event, scope, &list, &count);
        if (ret < 0)
                goto end;

        if (count == 0)
                goto end;

        g_hash_table_iter_init(&iter, global_perf_liszt);
        while (g_hash_table_iter_next (&iter, &key, (gpointer) &perfcounter)) {
                field = bt_ctf_get_field(event, scope, (char *) key);
                if (field) {
                        int value = bt_ctf_get_uint64(field);
                        if (bt_ctf_field_get_error())
                                continue;
                        update_perf_value(proc, cpu, (char *) key, value);
                }
        }

end:
        return;
}

void update_perf_counter(struct processtop *proc, const struct bt_ctf_event *event)
{
        struct cputime *cpu;
        const struct bt_definition *scope;

        cpu = get_cpu(get_cpu_id(event));

        scope = bt_ctf_get_top_level_scope(event, BT_STREAM_EVENT_CONTEXT);
        extract_perf_counter_scope(event, scope, proc, cpu);

        scope = bt_ctf_get_top_level_scope(event, BT_STREAM_PACKET_CONTEXT);
        extract_perf_counter_scope(event, scope, proc, cpu);

        scope = bt_ctf_get_top_level_scope(event, BT_EVENT_CONTEXT);
        extract_perf_counter_scope(event, scope, proc, cpu);
}

enum bt_cb_ret fix_process_table(struct bt_ctf_event *call_data,
                void *private_data)
{
        int pid, tid, ppid, vpid, vtid, vppid;
        char *comm, *hostname;
        struct processtop *parent, *child;
        unsigned long timestamp;

        timestamp = bt_ctf_get_timestamp(call_data);
        if (timestamp == -1ULL)
                goto error;

        pid = get_context_pid(call_data);
        if (pid == -1ULL) {
                goto error;
        }

        tid = get_context_tid(call_data);
        if (tid == -1ULL) {
                goto error;
        }
        ppid = get_context_ppid(call_data);
        if (ppid == -1ULL) {
                goto error;
        }
        vpid = get_context_vpid(call_data);
        if (pid == -1ULL) {
                vpid = -1;
        }
        vtid = get_context_vtid(call_data);
        if (tid == -1ULL) {
                vtid = -1;
        }
        vppid = get_context_vppid(call_data);
        if (ppid == -1ULL) {
                vppid = -1;
        }
        comm = get_context_comm(call_data);
        if (!comm) {
                goto error;
        }
        /* optional */
        hostname = get_context_hostname(call_data);

        /* find or create the current process */
        child = find_process_tid(&lttngtop, tid, comm);
        if (!child)
                child = add_proc(&lttngtop, tid, comm, timestamp, hostname);
        if (!child)
                goto end;
        update_proc(child, pid, tid, ppid, vpid, vtid, vppid, comm, hostname);

        if (pid != tid) {
                /* find or create the parent */
                parent = find_process_tid(&lttngtop, pid, comm);
                if (!parent) {
                        parent = add_proc(&lttngtop, pid, comm, timestamp, hostname);
                        if (parent)
                                parent->pid = pid;
                }

                /* attach the parent to the current process */
                child->threadparent = parent;
                add_thread(parent, child);
        }

        update_perf_counter(child, call_data);

end:
        return BT_CB_OK;

error:
        return BT_CB_ERROR_STOP;
}

void init_lttngtop()
{
        copies = g_ptr_array_new();
        global_perf_liszt = g_hash_table_new(g_str_hash, g_str_equal);
        global_filter_list = g_hash_table_new(g_str_hash, g_str_equal);
        global_host_list = g_hash_table_new(g_str_hash, g_str_equal);
        tid_filter_list = g_hash_table_new(g_str_hash,
                        g_str_equal);

        sem_init(&goodtodisplay, 0, 0);
        sem_init(&goodtoupdate, 0, 1);
        sem_init(&timer, 0, 1);
        sem_init(&bootstrap, 0, 0);
        sem_init(&pause_sem, 0, 1);
        sem_init(&end_trace_sem, 0, 0);

        reset_global_counters();
        lttngtop.nbproc = 0;
        lttngtop.nbthreads = 0;
        lttngtop.nbfiles = 0;

        lttngtop.process_hash_table = g_hash_table_new(g_direct_hash,
                        g_direct_equal);
        lttngtop.process_table = g_ptr_array_new();
        lttngtop.files_table = g_ptr_array_new();
        lttngtop.cpu_table = g_ptr_array_new();

        toggle_filter = -1;
}

void usage(FILE *fp)
{
        fprintf(fp, "LTTngTop %s\n\n", VERSION);
        fprintf(fp, "Usage : lttngtop [OPTIONS] TRACE\n");
        fprintf(fp, "  TRACE                    Path to the trace to analyse (-r for network live tracing, nothing for mmap live streaming)\n");
        fprintf(fp, "  -h, --help               This help message\n");
        fprintf(fp, "  -t, --textdump           Display live events in text-only\n");
        fprintf(fp, "  -p, --pid                Comma-separated list of PIDs to display\n");
        fprintf(fp, "  -f, --child              Follow threads associated with selected PIDs\n");
        fprintf(fp, "  -n, --hostname           Comma-separated list of hostnames to display (require hostname context in trace)\n");
        fprintf(fp, "  -k, --kprobes            Comma-separated list of kprobes to insert (same format as lttng enable-event)\n");
        fprintf(fp, "  -r, --relay-hostname     Network live streaming : hostname of the lttng-relayd (default port)\n");
        fprintf(fp, "  -b, --begin              Network live streaming : read the trace for the beginning of the recording\n");
}

/*
 * Parse probe options.
 * Shamelessly stolen from lttng-tools :
 * src/bin/lttng/commands/enable_events.c
 */
static struct kprobes *parse_probe_opts(char *opt)
{
        char s_hex[19];
        char name[LTTNG_SYMBOL_NAME_LEN];
        struct kprobes *kprobe;
        int ret;

        /*
        kprobe->probe_addr = 0;
        kprobe->probe_offset = 0;
        asprintf(&kprobe->probe_name, "probe_sys_open");
        asprintf(&kprobe->symbol_name, "sys_open");
        */

        if (opt == NULL) {
                kprobe = NULL;
                goto end;
        }

        kprobe = g_new0(struct kprobes, 1);

        /* Check for symbol+offset */
        ret = sscanf(opt, "%[^'+']+%s", name, s_hex);
        if (ret == 2) {
                ret = asprintf(&kprobe->probe_name, "probe_%s", name);
                ret = asprintf(&kprobe->symbol_name, "%s", name);

                if (strlen(s_hex) == 0) {
                        fprintf(stderr, "Invalid probe offset %s", s_hex);
                        ret = -1;
                        goto end;
                }
                kprobe->probe_offset = strtoul(s_hex, NULL, 0);
                kprobe->probe_addr = 0;
                goto end;
        }

        /* Check for symbol */
        if (isalpha(name[0])) {
                ret = sscanf(opt, "%s", name);
                if (ret == 1) {
                        ret = asprintf(&kprobe->probe_name, "probe_%s", name);
                        ret = asprintf(&kprobe->symbol_name, "%s", name);
                        kprobe->probe_offset = 0;
                        kprobe->probe_addr = 0;
                        goto end;
                }
        }

        /* Check for address */
        ret = sscanf(opt, "%s", s_hex);
        if (ret > 0) {
                if (strlen(s_hex) == 0) {
                        fprintf(stderr, "Invalid probe address %s", s_hex);
                        ret = -1;
                        goto end;
                }
                ret = asprintf(&kprobe->probe_name, "probe_%s", s_hex);
                kprobe->probe_offset = 0;
                kprobe->probe_addr = strtoul(s_hex, NULL, 0);
                goto end;
        }

        /* No match */
        kprobe = NULL;

end:
        return kprobe;
}

/*
 * Return 0 if caller should continue, < 0 if caller should return
 * error, > 0 if caller should exit without reporting error.
 */
static int parse_options(int argc, char **argv)
{
        poptContext pc;
        int opt, ret = 0;
        char *tmp_str;
        int *tid;
        int i;

        remote_live = 0;

        pc = poptGetContext(NULL, argc, (const char **) argv, long_options, 0);
        poptReadDefaultConfig(pc, 0);

        while ((opt = poptGetNextOpt(pc)) != -1) {
                switch (opt) {
                        case OPT_HELP:
                                usage(stdout);
                                ret = 1;    /* exit cleanly */
                                goto end;
                        case OPT_TEXTDUMP:
                                opt_textdump = 1;
                                break;
                        case OPT_CHILD:
                                opt_child = 1;
                                break;
                        case OPT_PID:
                                toggle_filter = 1;
                                tmp_str = strtok(opt_tid, ",");
                                while (tmp_str) {
                                        tid = malloc(sizeof(int));
                                        *tid = atoi(tmp_str);
                                        g_hash_table_insert(tid_filter_list,
                                                        (gpointer) tid, tid);
                                        tmp_str = strtok(NULL, ",");
                                }
                                break;
                        case OPT_BEGIN:
                                /* start reading the live trace from the beginning */
                                opt_begin = 1;
                                break;
                        case OPT_HOSTNAME:
                                toggle_filter = 1;
                                tmp_str = strtok(opt_hostname, ",");
                                while (tmp_str) {
                                        add_hostname_list(tmp_str, 1);
                                        tmp_str = strtok(NULL, ",");
                                }
                                break;
                        case OPT_RELAY_HOSTNAME:
                                remote_live = 1;
                                break;
                        case OPT_KPROBES:
                                lttngtop.kprobes_table = g_ptr_array_new();
                                tmp_str = strtok(opt_kprobes, ",");
                                while (tmp_str) {
                                        struct kprobes *kprobe;

                                        kprobe = parse_probe_opts(tmp_str);
                                        if (kprobe) {
                                                g_ptr_array_add(
                                                        lttngtop.kprobes_table,
                                                        kprobe);
                                        } else {
                                                ret = -EINVAL;
                                                goto end;
                                        }
                                        tmp_str = strtok(NULL, ",");
                                }
                                break;
                        default:
                                ret = -EINVAL;
                                goto end;
                }
        }

        opt_exec_name = NULL;
        opt_exec_argv = NULL;
        for (i = 0; i < argc; i++) {
                if (argv[i][0] == '-' && argv[i][1] == '-') {
                        opt_exec_name = argv[i + 1];
                        opt_exec_argv = &argv[i + 1];
                        break;
                }
        }
        if (!opt_exec_name) {
                opt_input_path = poptGetArg(pc);
        }

end:
        if (pc) {
                poptFreeContext(pc);
        }
        return ret;
}

void iter_trace(struct bt_context *bt_ctx)
{
        struct bt_ctf_iter *iter;
        struct bt_iter_pos begin_pos;
        struct kprobes *kprobe;
        const struct bt_ctf_event *event;
        int i;
        int ret = 0;

        begin_pos.type = BT_SEEK_BEGIN;
        iter = bt_ctf_iter_create(bt_ctx, &begin_pos, NULL);

        /* at each event, verify the status of the process table */
        bt_ctf_iter_add_callback(iter, 0, NULL, 0,
                        fix_process_table,
                        NULL, NULL, NULL);
        /* to handle the follow child option */
        bt_ctf_iter_add_callback(iter,
                        g_quark_from_static_string("sched_process_fork"),
                        NULL, 0, handle_sched_process_fork, NULL, NULL, NULL);
        /* to clean up the process table */
        bt_ctf_iter_add_callback(iter,
                        g_quark_from_static_string("sched_process_free"),
                        NULL, 0, handle_sched_process_free, NULL, NULL, NULL);
        if (opt_textdump) {
                bt_ctf_iter_add_callback(iter, 0, NULL, 0,
                                print_timestamp,
                                NULL, NULL, NULL);
        } else {
                /* at each event check if we need to refresh */
                bt_ctf_iter_add_callback(iter, 0, NULL, 0,
                                check_timestamp,
                                NULL, NULL, NULL);
                /* to handle the scheduling events */
                bt_ctf_iter_add_callback(iter,
                                g_quark_from_static_string("sched_switch"),
                                NULL, 0, handle_sched_switch, NULL, NULL, NULL);
                /* to get all the process from the statedumps */
                bt_ctf_iter_add_callback(iter,
                                g_quark_from_static_string(
                                        "lttng_statedump_process_state"),
                                NULL, 0, handle_statedump_process_state,
                                NULL, NULL, NULL);

                /* for IO top */
                bt_ctf_iter_add_callback(iter,
                                g_quark_from_static_string("exit_syscall"),
                                NULL, 0, handle_exit_syscall, NULL, NULL, NULL);
                bt_ctf_iter_add_callback(iter,
                                g_quark_from_static_string("sys_write"),
                                NULL, 0, handle_sys_write, NULL, NULL, NULL);
                bt_ctf_iter_add_callback(iter,
                                g_quark_from_static_string("sys_read"),
                                NULL, 0, handle_sys_read, NULL, NULL, NULL);
                bt_ctf_iter_add_callback(iter,
                                g_quark_from_static_string("sys_open"),
                                NULL, 0, handle_sys_open, NULL, NULL, NULL);
                bt_ctf_iter_add_callback(iter,
                                g_quark_from_static_string("sys_close"),
                                NULL, 0, handle_sys_close, NULL, NULL, NULL);
                bt_ctf_iter_add_callback(iter,
                                g_quark_from_static_string(
                                        "lttng_statedump_file_descriptor"),
                                NULL, 0, handle_statedump_file_descriptor,
                                NULL, NULL, NULL);

                /* for kprobes */
                if (lttngtop.kprobes_table) {
                        for (i = 0; i < lttngtop.kprobes_table->len; i++) {
                                kprobe = g_ptr_array_index(lttngtop.kprobes_table, i);
                                bt_ctf_iter_add_callback(iter,
                                                g_quark_from_static_string(
                                                        kprobe->probe_name),
                                                NULL, 0, handle_kprobes,
                                                NULL, NULL, NULL);
                        }
                }
        }

        if (opt_exec_name) {
                pid_t pid;

                pid = fork();
                if (pid == 0) {
                        execvpe(opt_exec_name, opt_exec_argv, opt_exec_env);
                        exit(EXIT_SUCCESS);
                } else if (pid > 0) {
                        opt_exec_pid = pid;
                        g_hash_table_insert(tid_filter_list,
                                        (gpointer) &pid,
                                        &pid);
                } else {
                        perror("fork");
                        exit(EXIT_FAILURE);
                }
        }

        while ((event = bt_ctf_iter_read_event(iter)) != NULL) {
                if (quit || reload_trace)
                        goto end_iter;
                ret = bt_iter_next(bt_ctf_get_iter(iter));
                if (ret < 0)
                        goto end_iter;
        }

        /* block until quit, we reached the end of the trace */
        sem_wait(&end_trace_sem);

end_iter:
        bt_ctf_iter_destroy(iter);
}

/*
 * bt_context_add_traces_recursive: Open a trace recursively
 * (copied from BSD code in converter/babeltrace.c)
 *
 * Find each trace present in the subdirectory starting from the given
 * path, and add them to the context. The packet_seek parameter can be
 * NULL: this specify to use the default format packet_seek.
 *
 * Return: 0 on success, nonzero on failure.
 * Unable to open toplevel: failure.
 * Unable to open some subdirectory or file: warn and continue;
 */
int bt_context_add_traces_recursive(struct bt_context *ctx, const char *path,
                const char *format_str,
                void (*packet_seek)(struct bt_stream_pos *pos,
                        size_t offset, int whence))
{
        FTS *tree;
        FTSENT *node;
        GArray *trace_ids;
        char lpath[PATH_MAX];
        char * const paths[2] = { lpath, NULL };
        int ret = -1;

        if ((strncmp(path, NET4_URL_PREFIX, sizeof(NET4_URL_PREFIX) - 1)) == 0 ||
                        (strncmp(path, NET6_URL_PREFIX, sizeof(NET6_URL_PREFIX) - 1)) == 0 ||
                        (strncmp(path, NET_URL_PREFIX, sizeof(NET_URL_PREFIX) - 1)) == 0) {
                ret = bt_context_add_trace(ctx,
                                path, format_str, packet_seek, NULL, NULL);
                if (ret < 0) {
                        fprintf(stderr, "[warning] [Context] cannot open trace \"%s\" "
                                        "for reading.\n", path);
                        /* Allow to skip erroneous traces. */
                        ret = 1;        /* partial error */
                }
                return ret;
        }
        /*
         * Need to copy path, because fts_open can change it.
         * It is the pointer array, not the strings, that are constant.
         */
        strncpy(lpath, path, PATH_MAX);
        lpath[PATH_MAX - 1] = '\0';

        tree = fts_open(paths, FTS_NOCHDIR | FTS_LOGICAL, 0);
        if (tree == NULL) {
                fprintf(stderr, "[error] [Context] Cannot traverse \"%s\" for reading.\n",
                                path);
                return -EINVAL;
        }

        trace_ids = g_array_new(FALSE, TRUE, sizeof(int));

        while ((node = fts_read(tree))) {
                int dirfd, metafd;

                if (!(node->fts_info & FTS_D))
                        continue;

                dirfd = open(node->fts_accpath, 0);
                if (dirfd < 0) {
                        fprintf(stderr, "[error] [Context] Unable to open trace "
                                "directory file descriptor.\n");
                        ret = dirfd;
                        goto error;
                }
                metafd = openat(dirfd, "metadata", O_RDONLY);
                if (metafd < 0) {
                        close(dirfd);
                        continue;
                } else {
                        int trace_id;

                        ret = close(metafd);
                        if (ret < 0) {
                                perror("close");
                                goto error;
                        }
                        ret = close(dirfd);
                        if (ret < 0) {
                                perror("close");
                                goto error;
                        }

                        trace_id = bt_context_add_trace(ctx,
                                node->fts_accpath, format_str,
                                packet_seek, NULL, NULL);
                        if (trace_id < 0) {
                                fprintf(stderr, "[warning] [Context] opening trace \"%s\" from %s "
                                        "for reading.\n", node->fts_accpath, path);
                                /* Allow to skip erroneous traces. */
                                continue;
                        }
                        g_array_append_val(trace_ids, trace_id);
                }
        }

        g_array_free(trace_ids, TRUE);
        return ret;

error:
        return ret;
}

static int check_field_requirements(const struct bt_ctf_field_decl *const * field_list,
                int field_cnt, int *tid_check, int *pid_check,
                int *procname_check, int *ppid_check)
{
        int j;
        struct perfcounter *global;
        const char *name;

        for (j = 0; j < field_cnt; j++) {
                name = bt_ctf_get_decl_field_name(field_list[j]);
                if (*tid_check == 0) {
                        if (strncmp(name, "tid", 3) == 0)
                                (*tid_check)++;
                }
                if (*pid_check == 0) {
                        if (strncmp(name, "pid", 3) == 0)
                                (*pid_check)++;
                }
                if (*ppid_check == 0) {
                        if (strncmp(name, "ppid", 4) == 0)
                                (*ppid_check)++;
                }
                if (*procname_check == 0) {
                        if (strncmp(name, "procname", 8) == 0)
                                (*procname_check)++;
                }
                if (strncmp(name, "perf_", 5) == 0) {
                        global = g_hash_table_lookup(global_perf_liszt, (gpointer) name);
                        if (!global) {
                                global = g_new0(struct perfcounter, 1);
                                /* by default, sort on the first perf context */
                                if (g_hash_table_size(global_perf_liszt) == 0)
                                        global->sort = 1;
                                global->visible = 1;
                                g_hash_table_insert(global_perf_liszt, (gpointer) strdup(name), global);
                        }
                }
        }

        if (*tid_check == 1 && *pid_check == 1 && *ppid_check == 1 &&
                        *procname_check == 1)
                return 0;

        return -1;
}

/*
 * check_requirements: check if the required context informations are available
 *
 * If each mandatory context information is available for at least in one
 * event, return 0 otherwise return -1.
 */
int check_requirements(struct bt_context *ctx)
{
        unsigned int i, evt_cnt, field_cnt;
        struct bt_ctf_event_decl *const * evt_list;
        const struct bt_ctf_field_decl *const * field_list;
        int tid_check = 0;
        int pid_check = 0;
        int procname_check = 0;
        int ppid_check = 0;
        int ret = 0;

        ret = bt_ctf_get_event_decl_list(0, ctx, &evt_list, &evt_cnt);
        if (ret < 0) {
                goto end;
        }

        for (i = 0; i < evt_cnt; i++) {
                bt_ctf_get_decl_fields(evt_list[i], BT_STREAM_EVENT_CONTEXT,
                                &field_list, &field_cnt);
                ret = check_field_requirements(field_list, field_cnt,
                                &tid_check, &pid_check, &procname_check,
                                &ppid_check);

                bt_ctf_get_decl_fields(evt_list[i], BT_EVENT_CONTEXT,
                                &field_list, &field_cnt);
                ret = check_field_requirements(field_list, field_cnt,
                                &tid_check, &pid_check, &procname_check,
                                &ppid_check);

                bt_ctf_get_decl_fields(evt_list[i], BT_STREAM_PACKET_CONTEXT,
                                &field_list, &field_cnt);
                ret = check_field_requirements(field_list, field_cnt,
                                &tid_check, &pid_check, &procname_check,
                                &ppid_check);
        }

        if (tid_check == 0) {
                ret = -1;
                fprintf(stderr, "[error] missing tid context information\n");
        }
        if (pid_check == 0) {
                ret = -1;
                fprintf(stderr, "[error] missing pid context information\n");
        }
        if (ppid_check == 0) {
                ret = -1;
                fprintf(stderr, "[error] missing ppid context information\n");
        }
        if (procname_check == 0) {
                ret = -1;
                fprintf(stderr, "[error] missing procname context information\n");
        }

end:
        return ret;
}

static void handle_sigchild(int signal)
{
        int status;

        waitpid(opt_exec_pid, &status, 0);
}

int main(int argc, char **argv, char **envp)
{
        int ret;
        struct bt_context *bt_ctx = NULL;

        //babeltrace_verbose = 1;
        init_lttngtop();
        ret = parse_options(argc, argv);
        if (ret < 0) {
                fprintf(stdout, "Error parsing options.\n\n");
                usage(stdout);
                exit(EXIT_FAILURE);
        } else if (ret > 0) {
                exit(EXIT_SUCCESS);
        }

        if (opt_exec_name) {
                opt_exec_env = envp;
                signal(SIGCHLD, handle_sigchild);
        }

        if (!opt_input_path && !remote_live && !opt_exec_name) {
                /* mmap live */
#ifdef LTTNGTOP_MMAP_LIVE
                if (opt_textdump) {
                        signal(SIGTERM, handle_textdump_sigterm);
                        signal(SIGINT, handle_textdump_sigterm);
                }
                mmap_live_loop(bt_ctx);
                pthread_join(timer_thread, NULL);
                quit = 1;
                pthread_join(display_thread, NULL);

                lttng_stop_tracing("test");
                lttng_destroy_session("test");

                goto end;
#else
                fprintf(stderr, "[ERROR] Mmap live support not compiled, specify a "
                                "trace directory or -r <relayd hostname/IP>\n");
                usage(stdout);
                ret = -1;
                goto end;
#endif /* LTTNGTOP_MMAP_LIVE */
        } else if (!opt_input_path && remote_live) {
                /* network live */
                bt_ctx = bt_context_create();
                ret = bt_context_add_traces_recursive(bt_ctx, opt_relay_hostname,
                                "lttng-live", NULL);
                if (ret < 0) {
                        fprintf(stderr, "[error] Opening the trace\n");
                        goto end;
                }
        } else {
                //init_lttngtop();

                bt_ctx = bt_context_create();
                ret = bt_context_add_traces_recursive(bt_ctx, opt_input_path, "ctf", NULL);
                if (ret < 0) {
                        fprintf(stderr, "[error] Opening the trace\n");
                        goto end;
                }

                ret = check_requirements(bt_ctx);
                if (ret < 0) {
                        fprintf(stderr, "[error] some mandatory contexts "
                                        "were missing, exiting.\n");
                        goto end;
                }

                if (!opt_textdump) {
                        pthread_create(&display_thread, NULL, ncurses_display,
                                        (void *) NULL);
                        pthread_create(&timer_thread, NULL, refresh_thread,
                                        (void *) NULL);
                }

                iter_trace(bt_ctx);
        }


        pthread_join(display_thread, NULL);
        quit = 1;
        pthread_join(timer_thread, NULL);

        ret = 0;

end:
        if (bt_ctx)
                bt_context_put(bt_ctx);

        return ret;
}