[babeltrace.git] / src / plugins / ctf / fs-src / data-stream-file.cpp

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright 2016-2017 Philippe Proulx <pproulx@efficios.com>
 * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 * Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
 */

#define BT_COMP_LOG_SELF_COMP (self_comp)
#define BT_LOG_OUTPUT_LEVEL (log_level)
#define BT_LOG_TAG "PLUGIN/SRC.CTF.FS/DS"
#include "logging/comp-logging.h"

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <glib.h>
#include <inttypes.h>
#include "compat/mman.h"
#include "compat/endian.h"
#include <babeltrace2/babeltrace.h>
#include "common/common.h"
#include "file.hpp"
#include "metadata.hpp"
#include "../common/msg-iter/msg-iter.hpp"
#include "common/assert.h"
#include "data-stream-file.hpp"
#include <string.h>

static inline
size_t remaining_mmap_bytes(struct ctf_fs_ds_file *ds_file)
{
        BT_ASSERT_DBG(ds_file->mmap_len >= ds_file->request_offset_in_mapping);
        return ds_file->mmap_len - ds_file->request_offset_in_mapping;
}

/*
 * Return true if `offset_in_file` is in the current mapping.
 */

static
bool offset_ist_mapped(struct ctf_fs_ds_file *ds_file, off_t offset_in_file)
{
        return offset_in_file >= ds_file->mmap_offset_in_file &&
                offset_in_file < (ds_file->mmap_offset_in_file + ds_file->mmap_len);
}

static
enum ctf_msg_iter_medium_status ds_file_munmap(
                struct ctf_fs_ds_file *ds_file)
{
        enum ctf_msg_iter_medium_status status;
        bt_self_component *self_comp = ds_file->self_comp;
        bt_logging_level log_level = ds_file->log_level;

        BT_ASSERT(ds_file);

        if (!ds_file->mmap_addr) {
                status = CTF_MSG_ITER_MEDIUM_STATUS_OK;
                goto end;
        }

        if (bt_munmap(ds_file->mmap_addr, ds_file->mmap_len)) {
                BT_COMP_LOGE_ERRNO("Cannot memory-unmap file",
                        ": address=%p, size=%zu, file_path=\"%s\", file=%p",
                        ds_file->mmap_addr, ds_file->mmap_len,
                        ds_file->file ? ds_file->file->path->str : "NULL",
                        ds_file->file ? ds_file->file->fp : NULL);
                status = CTF_MSG_ITER_MEDIUM_STATUS_ERROR;
                goto end;
        }

        ds_file->mmap_addr = NULL;

        status = CTF_MSG_ITER_MEDIUM_STATUS_OK;
end:
        return status;
}

/*
 * mmap a region of `ds_file` such that `requested_offset_in_file` is in the
 * mapping.  If the currently mmap-ed region already contains
 * `requested_offset_in_file`, the mapping is kept.
 *
 * Set `ds_file->requested_offset_in_mapping` based on `request_offset_in_file`,
 * such that the next call to `request_bytes` will return bytes starting at that
 * position.
 *
 * `requested_offset_in_file` must be a valid offset in the file.
 */
static
enum ctf_msg_iter_medium_status ds_file_mmap(
                struct ctf_fs_ds_file *ds_file, off_t requested_offset_in_file)
{
        enum ctf_msg_iter_medium_status status;
        bt_self_component *self_comp = ds_file->self_comp;
        bt_logging_level log_level = ds_file->log_level;

        /* Ensure the requested offset is in the file range. */
        BT_ASSERT(requested_offset_in_file >= 0);
        BT_ASSERT(requested_offset_in_file < ds_file->file->size);

        /*
         * If the mapping already contains the requested offset, just adjust
         * requested_offset_in_mapping.
         */
        if (offset_ist_mapped(ds_file, requested_offset_in_file)) {
                ds_file->request_offset_in_mapping =
                        requested_offset_in_file - ds_file->mmap_offset_in_file;
                status = CTF_MSG_ITER_MEDIUM_STATUS_OK;
                goto end;
        }

        /* Unmap old region */
        status = ds_file_munmap(ds_file);
        if (status != CTF_MSG_ITER_MEDIUM_STATUS_OK) {
                goto end;
        }

        /*
         * Compute a mapping that has the required alignment properties and
         * contains `requested_offset_in_file`.
         */
        ds_file->request_offset_in_mapping =
                requested_offset_in_file % bt_mmap_get_offset_align_size(ds_file->log_level);
        ds_file->mmap_offset_in_file =
                requested_offset_in_file - ds_file->request_offset_in_mapping;
        ds_file->mmap_len = MIN(ds_file->file->size - ds_file->mmap_offset_in_file,
                ds_file->mmap_max_len);

        BT_ASSERT(ds_file->mmap_len > 0);

        ds_file->mmap_addr = bt_mmap((void *) 0, ds_file->mmap_len,
                        PROT_READ, MAP_PRIVATE, fileno(ds_file->file->fp),
                        ds_file->mmap_offset_in_file, ds_file->log_level);
        if (ds_file->mmap_addr == MAP_FAILED) {
                BT_COMP_LOGE("Cannot memory-map address (size %zu) of file \"%s\" (%p) at offset %jd: %s",
                                ds_file->mmap_len, ds_file->file->path->str,
                                ds_file->file->fp, (intmax_t) ds_file->mmap_offset_in_file,
                                strerror(errno));
                status = CTF_MSG_ITER_MEDIUM_STATUS_ERROR;
                goto end;
        }

        status = CTF_MSG_ITER_MEDIUM_STATUS_OK;

end:
        return status;
}

/*
 * Change the mapping of the file to read the region that follows the current
 * mapping.
 *
 * If the file hasn't been mapped yet, then everything (mmap_offset_in_file,
 * mmap_len, request_offset_in_mapping) should have the value 0, which will
 * result in the beginning of the file getting mapped.
 *
 * return _EOF if the current mapping is the end of the file.
 */

static
enum ctf_msg_iter_medium_status ds_file_mmap_next(
                struct ctf_fs_ds_file *ds_file)
{
        enum ctf_msg_iter_medium_status status;

        /*
         * If we're called, it's because more bytes are requested but we have
         * given all the bytes of the current mapping.
         */
        BT_ASSERT(ds_file->request_offset_in_mapping == ds_file->mmap_len);

        /*
         * If the current mapping coincides with the end of the file, there is
         * no next mapping.
         */
        if (ds_file->mmap_offset_in_file + ds_file->mmap_len == ds_file->file->size) {
                status = CTF_MSG_ITER_MEDIUM_STATUS_EOF;
                goto end;
        }

        status = ds_file_mmap(ds_file,
                ds_file->mmap_offset_in_file + ds_file->mmap_len);

end:
        return status;
}

static
enum ctf_msg_iter_medium_status medop_request_bytes(
                size_t request_sz, uint8_t **buffer_addr,
                size_t *buffer_sz, void *data)
{
        enum ctf_msg_iter_medium_status status =
                CTF_MSG_ITER_MEDIUM_STATUS_OK;
        struct ctf_fs_ds_file *ds_file = (struct ctf_fs_ds_file *) data;
        bt_self_component *self_comp = ds_file->self_comp;
        bt_logging_level log_level = ds_file->log_level;

        BT_ASSERT(request_sz > 0);

        /*
         * Check if we have at least one memory-mapped byte left. If we don't,
         * mmap the next file.
         */
        if (remaining_mmap_bytes(ds_file) == 0) {
                /* Are we at the end of the file? */
                if (ds_file->mmap_offset_in_file >= ds_file->file->size) {
                        BT_COMP_LOGD("Reached end of file \"%s\" (%p)",
                                ds_file->file->path->str, ds_file->file->fp);
                        status = CTF_MSG_ITER_MEDIUM_STATUS_EOF;
                        goto end;
                }

                status = ds_file_mmap_next(ds_file);
                switch (status) {
                case CTF_MSG_ITER_MEDIUM_STATUS_OK:
                        break;
                case CTF_MSG_ITER_MEDIUM_STATUS_EOF:
                        goto end;
                default:
                        BT_COMP_LOGE("Cannot memory-map next region of file \"%s\" (%p)",
                                        ds_file->file->path->str,
                                        ds_file->file->fp);
                        goto error;
                }
        }

        BT_ASSERT(remaining_mmap_bytes(ds_file) > 0);
        *buffer_sz = MIN(remaining_mmap_bytes(ds_file), request_sz);

        BT_ASSERT(ds_file->mmap_addr);
        *buffer_addr = ((uint8_t *) ds_file->mmap_addr) + ds_file->request_offset_in_mapping;

        ds_file->request_offset_in_mapping += *buffer_sz;
        goto end;

error:
        status = CTF_MSG_ITER_MEDIUM_STATUS_ERROR;

end:
        return status;
}

static
bt_stream *medop_borrow_stream(bt_stream_class *stream_class, int64_t stream_id,
                void *data)
{
        struct ctf_fs_ds_file *ds_file = (struct ctf_fs_ds_file *) data;
        bt_stream_class *ds_file_stream_class;
        bt_stream *stream = NULL;

        ds_file_stream_class = bt_stream_borrow_class(
                ds_file->stream);

        if (stream_class != ds_file_stream_class) {
                /*
                 * Not supported: two packets described by two different
                 * stream classes within the same data stream file.
                 */
                goto end;
        }

        stream = ds_file->stream;

end:
        return stream;
}

static
enum ctf_msg_iter_medium_status medop_seek(off_t offset, void *data)
{
        struct ctf_fs_ds_file *ds_file = (struct ctf_fs_ds_file *) data;

        BT_ASSERT(offset >= 0);
        BT_ASSERT(offset < ds_file->file->size);

        return ds_file_mmap(ds_file, offset);
}

BT_HIDDEN
struct ctf_msg_iter_medium_ops ctf_fs_ds_file_medops = {
        medop_request_bytes,
        medop_seek,
        nullptr,
        medop_borrow_stream,
};

struct ctf_fs_ds_group_medops_data {
        /* Weak, set once at creation time. */
        struct ctf_fs_ds_file_group *ds_file_group;

        /*
         * Index (as in element rank) of the index entry of ds_file_groups'
         * index we will read next (so, the one after the one we are reading
         * right now).
         */
        guint next_index_entry_index;

        /*
         * File we are currently reading.  Changes whenever we switch to
         * reading another data file.
         *
         * Owned by this.
         */
        struct ctf_fs_ds_file *file;

        /* Weak, for context / logging / appending causes. */
        bt_self_message_iterator *self_msg_iter;
        bt_logging_level log_level;
};

static
enum ctf_msg_iter_medium_status medop_group_request_bytes(
                size_t request_sz,
                uint8_t **buffer_addr,
                size_t *buffer_sz,
                void *void_data)
{
        struct ctf_fs_ds_group_medops_data *data = (struct ctf_fs_ds_group_medops_data *)  void_data;

        /* Return bytes from the current file. */
        return medop_request_bytes(request_sz, buffer_addr, buffer_sz, data->file);
}

static
bt_stream *medop_group_borrow_stream(
                bt_stream_class *stream_class,
                int64_t stream_id,
                void *void_data)
{
        struct ctf_fs_ds_group_medops_data *data = (struct ctf_fs_ds_group_medops_data *) void_data;

        return medop_borrow_stream(stream_class, stream_id, data->file);
}

/*
 * Set `data->file` to prepare it to read the packet described
 * by `index_entry`.
 */

static
enum ctf_msg_iter_medium_status ctf_fs_ds_group_medops_set_file(
                struct ctf_fs_ds_group_medops_data *data,
                struct ctf_fs_ds_index_entry *index_entry,
                bt_self_message_iterator *self_msg_iter,
                bt_logging_level log_level)
{
        enum ctf_msg_iter_medium_status status;

        BT_ASSERT(data);
        BT_ASSERT(index_entry);

        /* Check if that file is already the one mapped. */
        if (!data->file || strcmp(index_entry->path, data->file->file->path->str) != 0) {
                /* Destroy the previously used file. */
                ctf_fs_ds_file_destroy(data->file);

                /* Create the new file. */
                data->file = ctf_fs_ds_file_create(
                        data->ds_file_group->ctf_fs_trace,
                        self_msg_iter,
                        data->ds_file_group->stream,
                        index_entry->path,
                        log_level);
                if (!data->file) {
                        BT_MSG_ITER_LOGE_APPEND_CAUSE(self_msg_iter,
                                "failed to create ctf_fs_ds_file.");
                        status = CTF_MSG_ITER_MEDIUM_STATUS_ERROR;
                        goto end;
                }
        }

        /*
         * Ensure the right portion of the file will be returned on the next
         * request_bytes call.
         */
        status = ds_file_mmap(data->file, index_entry->offset);
        if (status != CTF_MSG_ITER_MEDIUM_STATUS_OK) {
                goto end;
        }

        status = CTF_MSG_ITER_MEDIUM_STATUS_OK;

end:
        return status;
}

static
enum ctf_msg_iter_medium_status medop_group_switch_packet(void *void_data)
{
        struct ctf_fs_ds_group_medops_data *data = (struct ctf_fs_ds_group_medops_data *) void_data;
        struct ctf_fs_ds_index_entry *index_entry;
        enum ctf_msg_iter_medium_status status;

        /* If we have gone through all index entries, we are done. */
        if (data->next_index_entry_index >=
                data->ds_file_group->index->entries->len) {
                status = CTF_MSG_ITER_MEDIUM_STATUS_EOF;
                goto end;
        }

        /*
         * Otherwise, look up the next index entry / packet and prepare it
         *  for reading.
         */
        index_entry = (struct ctf_fs_ds_index_entry *) g_ptr_array_index(
                data->ds_file_group->index->entries,
                data->next_index_entry_index);

        status = ctf_fs_ds_group_medops_set_file(
                data, index_entry, data->self_msg_iter, data->log_level);
        if (status != CTF_MSG_ITER_MEDIUM_STATUS_OK) {
                goto end;
        }

        data->next_index_entry_index++;

        status = CTF_MSG_ITER_MEDIUM_STATUS_OK;
end:
        return status;
}

BT_HIDDEN
void ctf_fs_ds_group_medops_data_destroy(
                struct ctf_fs_ds_group_medops_data *data)
{
        if (!data) {
                goto end;
        }

        ctf_fs_ds_file_destroy(data->file);

        g_free(data);

end:
        return;
}

enum ctf_msg_iter_medium_status ctf_fs_ds_group_medops_data_create(
                struct ctf_fs_ds_file_group *ds_file_group,
                bt_self_message_iterator *self_msg_iter,
                bt_logging_level log_level,
                struct ctf_fs_ds_group_medops_data **out)
{
        struct ctf_fs_ds_group_medops_data *data;
        enum ctf_msg_iter_medium_status status;

        BT_ASSERT(self_msg_iter);
        BT_ASSERT(ds_file_group);
        BT_ASSERT(ds_file_group->index);
        BT_ASSERT(ds_file_group->index->entries->len > 0);

        data = g_new0(struct ctf_fs_ds_group_medops_data, 1);
        if (!data) {
                BT_MSG_ITER_LOGE_APPEND_CAUSE(self_msg_iter,
                        "Failed to allocate a struct ctf_fs_ds_group_medops_data");
                status = CTF_MSG_ITER_MEDIUM_STATUS_MEMORY_ERROR;
                goto error;
        }

        data->ds_file_group = ds_file_group;
        data->self_msg_iter = self_msg_iter;
        data->log_level = log_level;

        /*
         * No need to prepare the first file.  ctf_msg_iter will call
         * switch_packet before reading the first packet, it will be
         * done then.
         */

        *out = data;
        status = CTF_MSG_ITER_MEDIUM_STATUS_OK;
        goto end;

error:
        ctf_fs_ds_group_medops_data_destroy(data);

end:
        return status;
}

void ctf_fs_ds_group_medops_data_reset(struct ctf_fs_ds_group_medops_data *data)
{
        data->next_index_entry_index = 0;
}

struct ctf_msg_iter_medium_ops ctf_fs_ds_group_medops = {
        .request_bytes = medop_group_request_bytes,

        /*
         * We don't support seeking using this medops.  It would probably be
         * possible, but it's not needed at the moment.
         */
        .seek = NULL,

        .switch_packet = medop_group_switch_packet,
        .borrow_stream = medop_group_borrow_stream,
};

static
struct ctf_fs_ds_index_entry *ctf_fs_ds_index_entry_create(
                bt_self_component *self_comp, bt_logging_level log_level)
{
        struct ctf_fs_ds_index_entry *entry;

        entry = g_new0(struct ctf_fs_ds_index_entry, 1);
        if (!entry) {
                BT_COMP_LOGE_APPEND_CAUSE(self_comp, "Failed to allocate a ctf_fs_ds_index_entry.");
                goto end;
        }

        entry->packet_seq_num = UINT64_MAX;

end:
        return entry;
}

static
int convert_cycles_to_ns(struct ctf_clock_class *clock_class,
                uint64_t cycles, int64_t *ns)
{
        return bt_util_clock_cycles_to_ns_from_origin(cycles,
                        clock_class->frequency, clock_class->offset_seconds,
                        clock_class->offset_cycles, ns);
}

static
struct ctf_fs_ds_index *build_index_from_idx_file(
                struct ctf_fs_ds_file *ds_file,
                struct ctf_fs_ds_file_info *file_info,
                struct ctf_msg_iter *msg_iter)
{
        int ret;
        gchar *directory = NULL;
        gchar *basename = NULL;
        GString *index_basename = NULL;
        gchar *index_file_path = NULL;
        GMappedFile *mapped_file = NULL;
        gsize filesize;
        const char *mmap_begin = NULL, *file_pos = NULL;
        const struct ctf_packet_index_file_hdr *header = NULL;
        struct ctf_fs_ds_index *index = NULL;
        struct ctf_fs_ds_index_entry *index_entry = NULL, *prev_index_entry = NULL;
        uint64_t total_packets_size = 0;
        size_t file_index_entry_size;
        size_t file_entry_count;
        size_t i;
        struct ctf_stream_class *sc;
        struct ctf_msg_iter_packet_properties props;
        uint32_t version_major, version_minor;
        bt_self_component *self_comp = ds_file->self_comp;
        bt_logging_level log_level = ds_file->log_level;

        BT_COMP_LOGI("Building index from .idx file of stream file %s",
                        ds_file->file->path->str);
        ret = ctf_msg_iter_get_packet_properties(msg_iter, &props);
        if (ret) {
                BT_COMP_LOGI_STR("Cannot read first packet's header and context fields.");
                goto error;
        }

        sc = ctf_trace_class_borrow_stream_class_by_id(ds_file->metadata->tc,
                props.stream_class_id);
        BT_ASSERT(sc);
        if (!sc->default_clock_class) {
                BT_COMP_LOGI_STR("Cannot find stream class's default clock class.");
                goto error;
        }

        /* Look for index file in relative path index/name.idx. */
        basename = g_path_get_basename(ds_file->file->path->str);
        if (!basename) {
                BT_COMP_LOGE("Cannot get the basename of datastream file %s",
                                ds_file->file->path->str);
                goto error;
        }

        directory = g_path_get_dirname(ds_file->file->path->str);
        if (!directory) {
                BT_COMP_LOGE("Cannot get dirname of datastream file %s",
                                ds_file->file->path->str);
                goto error;
        }

        index_basename = g_string_new(basename);
        if (!index_basename) {
                BT_COMP_LOGE_STR("Cannot allocate index file basename string");
                goto error;
        }

        g_string_append(index_basename, ".idx");
        index_file_path = g_build_filename(directory, "index",
                        index_basename->str, NULL);
        mapped_file = g_mapped_file_new(index_file_path, FALSE, NULL);
        if (!mapped_file) {
                BT_COMP_LOGD("Cannot create new mapped file %s",
                                index_file_path);
                goto error;
        }

        /*
         * The g_mapped_file API limits us to 4GB files on 32-bit.
         * Traces with such large indexes have never been seen in the wild,
         * but this would need to be adjusted to support them.
         */
        filesize = g_mapped_file_get_length(mapped_file);
        if (filesize < sizeof(*header)) {
                BT_COMP_LOGW("Invalid LTTng trace index file: "
                        "file size (%zu bytes) < header size (%zu bytes)",
                        filesize, sizeof(*header));
                goto error;
        }

        mmap_begin = g_mapped_file_get_contents(mapped_file);
        header = (struct ctf_packet_index_file_hdr *) mmap_begin;

        file_pos = g_mapped_file_get_contents(mapped_file) + sizeof(*header);
        if (be32toh(header->magic) != CTF_INDEX_MAGIC) {
                BT_COMP_LOGW_STR("Invalid LTTng trace index: \"magic\" field validation failed");
                goto error;
        }

        version_major = be32toh(header->index_major);
        version_minor = be32toh(header->index_minor);
        if (version_major != 1) {
                BT_COMP_LOGW(
                        "Unknown LTTng trace index version: "
                        "major=%" PRIu32 ", minor=%" PRIu32,
                        version_major, version_minor);
                goto error;
        }

        file_index_entry_size = be32toh(header->packet_index_len);
        if (file_index_entry_size < CTF_INDEX_1_0_SIZE) {
                BT_COMP_LOGW("Invalid `packet_index_len` in LTTng trace index file (`packet_index_len` < CTF index 1.0 index entry size): "
                        "packet_index_len=%zu, CTF_INDEX_1_0_SIZE=%zu",
                        file_index_entry_size, CTF_INDEX_1_0_SIZE);
                goto error;
        }

        file_entry_count = (filesize - sizeof(*header)) / file_index_entry_size;
        if ((filesize - sizeof(*header)) % file_index_entry_size) {
                BT_COMP_LOGW("Invalid LTTng trace index: the index's size after the header "
                        "(%zu bytes) is not a multiple of the index entry size "
                        "(%zu bytes)", (filesize - sizeof(*header)),
                        sizeof(*header));
                goto error;
        }

        index = ctf_fs_ds_index_create(ds_file->log_level, ds_file->self_comp);
        if (!index) {
                goto error;
        }

        for (i = 0; i < file_entry_count; i++) {
                struct ctf_packet_index *file_index =
                                (struct ctf_packet_index *) file_pos;
                uint64_t packet_size = be64toh(file_index->packet_size);

                if (packet_size % CHAR_BIT) {
                        BT_COMP_LOGW("Invalid packet size encountered in LTTng trace index file");
                        goto error;
                }

                index_entry = ctf_fs_ds_index_entry_create(
                        ds_file->self_comp, ds_file->log_level);
                if (!index_entry) {
                        BT_COMP_LOGE_APPEND_CAUSE(ds_file->self_comp,
                                "Failed to create a ctf_fs_ds_index_entry.");
                        goto error;
                }

                /* Set path to stream file. */
                index_entry->path = file_info->path->str;

                /* Convert size in bits to bytes. */
                packet_size /= CHAR_BIT;
                index_entry->packet_size = packet_size;

                index_entry->offset = be64toh(file_index->offset);
                if (i != 0 && index_entry->offset < prev_index_entry->offset) {
                        BT_COMP_LOGW("Invalid, non-monotonic, packet offset encountered in LTTng trace index file: "
                                "previous offset=%" PRIu64 ", current offset=%" PRIu64,
                                prev_index_entry->offset, index_entry->offset);
                        goto error;
                }

                index_entry->timestamp_begin = be64toh(file_index->timestamp_begin);
                index_entry->timestamp_end = be64toh(file_index->timestamp_end);
                if (index_entry->timestamp_end < index_entry->timestamp_begin) {
                        BT_COMP_LOGW("Invalid packet time bounds encountered in LTTng trace index file (begin > end): "
                                "timestamp_begin=%" PRIu64 "timestamp_end=%" PRIu64,
                                index_entry->timestamp_begin,
                                index_entry->timestamp_end);
                        goto error;
                }

                /* Convert the packet's bound to nanoseconds since Epoch. */
                ret = convert_cycles_to_ns(sc->default_clock_class,
                                index_entry->timestamp_begin,
                                &index_entry->timestamp_begin_ns);
                if (ret) {
                        BT_COMP_LOGI_STR("Failed to convert raw timestamp to nanoseconds since Epoch during index parsing");
                        goto error;
                }
                ret = convert_cycles_to_ns(sc->default_clock_class,
                                index_entry->timestamp_end,
                                &index_entry->timestamp_end_ns);
                if (ret) {
                        BT_COMP_LOGI_STR("Failed to convert raw timestamp to nanoseconds since Epoch during LTTng trace index parsing");
                        goto error;
                }

                if (version_minor >= 1) {
                        index_entry->packet_seq_num = be64toh(file_index->packet_seq_num);
                }

                total_packets_size += packet_size;
                file_pos += file_index_entry_size;

                prev_index_entry = index_entry;

                /* Give ownership of `index_entry` to `index->entries`. */
                g_ptr_array_add(index->entries, index_entry);
                index_entry = NULL;
        }

        /* Validate that the index addresses the complete stream. */
        if (ds_file->file->size != total_packets_size) {
                BT_COMP_LOGW("Invalid LTTng trace index file; indexed size != stream file size: "
                        "file-size=%" PRIu64 ", total-packets-size=%" PRIu64,
                        ds_file->file->size, total_packets_size);
                goto error;
        }
end:
        g_free(directory);
        g_free(basename);
        g_free(index_file_path);
        if (index_basename) {
                g_string_free(index_basename, TRUE);
        }
        if (mapped_file) {
                g_mapped_file_unref(mapped_file);
        }
        return index;
error:
        ctf_fs_ds_index_destroy(index);
        g_free(index_entry);
        index = NULL;
        goto end;
}

static
int init_index_entry(struct ctf_fs_ds_index_entry *entry,
                struct ctf_fs_ds_file *ds_file,
                struct ctf_msg_iter_packet_properties *props,
                off_t packet_size, off_t packet_offset)
{
        int ret = 0;
        struct ctf_stream_class *sc;
        bt_self_component *self_comp = ds_file->self_comp;
        bt_logging_level log_level = ds_file->log_level;

        sc = ctf_trace_class_borrow_stream_class_by_id(ds_file->metadata->tc,
                props->stream_class_id);
        BT_ASSERT(sc);
        BT_ASSERT(packet_offset >= 0);
        entry->offset = packet_offset;
        BT_ASSERT(packet_size >= 0);
        entry->packet_size = packet_size;

        if (props->snapshots.beginning_clock != UINT64_C(-1)) {
                entry->timestamp_begin = props->snapshots.beginning_clock;

                /* Convert the packet's bound to nanoseconds since Epoch. */
                ret = convert_cycles_to_ns(sc->default_clock_class,
                                           props->snapshots.beginning_clock,
                                           &entry->timestamp_begin_ns);
                if (ret) {
                        BT_COMP_LOGI_STR("Failed to convert raw timestamp to nanoseconds since Epoch.");
                        goto end;
                }
        } else {
                entry->timestamp_begin = UINT64_C(-1);
                entry->timestamp_begin_ns = UINT64_C(-1);
        }

        if (props->snapshots.end_clock != UINT64_C(-1)) {
                entry->timestamp_end = props->snapshots.end_clock;

                /* Convert the packet's bound to nanoseconds since Epoch. */
                ret = convert_cycles_to_ns(sc->default_clock_class,
                                           props->snapshots.end_clock,
                                           &entry->timestamp_end_ns);
                if (ret) {
                        BT_COMP_LOGI_STR("Failed to convert raw timestamp to nanoseconds since Epoch.");
                        goto end;
                }
        } else {
                entry->timestamp_end = UINT64_C(-1);
                entry->timestamp_end_ns = UINT64_C(-1);
        }

end:
        return ret;
}

static
struct ctf_fs_ds_index *build_index_from_stream_file(
                struct ctf_fs_ds_file *ds_file,
                struct ctf_fs_ds_file_info *file_info,
                struct ctf_msg_iter *msg_iter)
{
        int ret;
        struct ctf_fs_ds_index *index = NULL;
        enum ctf_msg_iter_status iter_status = CTF_MSG_ITER_STATUS_OK;
        off_t current_packet_offset_bytes = 0;
        bt_self_component *self_comp = ds_file->self_comp;
        bt_logging_level log_level = ds_file->log_level;

        BT_COMP_LOGI("Indexing stream file %s", ds_file->file->path->str);

        index = ctf_fs_ds_index_create(ds_file->log_level, ds_file->self_comp);
        if (!index) {
                goto error;
        }

        while (true) {
                off_t current_packet_size_bytes;
                struct ctf_fs_ds_index_entry *index_entry;
                struct ctf_msg_iter_packet_properties props;

                if (current_packet_offset_bytes < 0) {
                        BT_COMP_LOGE_STR("Cannot get the current packet's offset.");
                        goto error;
                } else if (current_packet_offset_bytes > ds_file->file->size) {
                        BT_COMP_LOGE_STR("Unexpected current packet's offset (larger than file).");
                        goto error;
                } else if (current_packet_offset_bytes == ds_file->file->size) {
                        /* No more data */
                        break;
                }

                iter_status = ctf_msg_iter_seek(msg_iter,
                                current_packet_offset_bytes);
                if (iter_status != CTF_MSG_ITER_STATUS_OK) {
                        goto error;
                }

                iter_status = ctf_msg_iter_get_packet_properties(
                        msg_iter, &props);
                if (iter_status != CTF_MSG_ITER_STATUS_OK) {
                        goto error;
                }

                if (props.exp_packet_total_size >= 0) {
                        current_packet_size_bytes =
                                (uint64_t) props.exp_packet_total_size / 8;
                } else {
                        current_packet_size_bytes = ds_file->file->size;
                }

                if (current_packet_offset_bytes + current_packet_size_bytes >
                                ds_file->file->size) {
                        BT_COMP_LOGW("Invalid packet size reported in file: stream=\"%s\", "
                                        "packet-offset=%jd, packet-size-bytes=%jd, "
                                        "file-size=%jd",
                                        ds_file->file->path->str,
                                        (intmax_t) current_packet_offset_bytes,
                                        (intmax_t) current_packet_size_bytes,
                                        (intmax_t) ds_file->file->size);
                        goto error;
                }

                index_entry = ctf_fs_ds_index_entry_create(
                        ds_file->self_comp, ds_file->log_level);
                if (!index_entry) {
                        BT_COMP_LOGE_APPEND_CAUSE(ds_file->self_comp,
                                "Failed to create a ctf_fs_ds_index_entry.");
                        goto error;
                }

                /* Set path to stream file. */
                index_entry->path = file_info->path->str;

                ret = init_index_entry(index_entry, ds_file, &props,
                        current_packet_size_bytes, current_packet_offset_bytes);
                if (ret) {
                        g_free(index_entry);
                        goto error;
                }

                g_ptr_array_add(index->entries, index_entry);

                current_packet_offset_bytes += current_packet_size_bytes;
                BT_COMP_LOGD("Seeking to next packet: current-packet-offset=%jd, "
                        "next-packet-offset=%jd",
                        (intmax_t) (current_packet_offset_bytes - current_packet_size_bytes),
                        (intmax_t) current_packet_offset_bytes);
        }

end:
        return index;

error:
        ctf_fs_ds_index_destroy(index);
        index = NULL;
        goto end;
}

BT_HIDDEN
struct ctf_fs_ds_file *ctf_fs_ds_file_create(
                struct ctf_fs_trace *ctf_fs_trace,
                bt_self_message_iterator *self_msg_iter,
                bt_stream *stream, const char *path,
                bt_logging_level log_level)
{
        int ret;
        const size_t offset_align = bt_mmap_get_offset_align_size(log_level);
        struct ctf_fs_ds_file *ds_file = g_new0(struct ctf_fs_ds_file, 1);

        if (!ds_file) {
                goto error;
        }

        ds_file->log_level = log_level;
        ds_file->self_comp = ctf_fs_trace->self_comp;
        ds_file->self_msg_iter = self_msg_iter;
        ds_file->file = ctf_fs_file_create(log_level, ds_file->self_comp);
        if (!ds_file->file) {
                goto error;
        }

        ds_file->stream = stream;
        bt_stream_get_ref(ds_file->stream);
        ds_file->metadata = ctf_fs_trace->metadata;
        g_string_assign(ds_file->file->path, path);
        ret = ctf_fs_file_open(ds_file->file, "rb");
        if (ret) {
                goto error;
        }

        ds_file->mmap_max_len = offset_align * 2048;

        goto end;

error:
        /* Do not touch "borrowed" file. */
        ctf_fs_ds_file_destroy(ds_file);
        ds_file = NULL;

end:
        return ds_file;
}

BT_HIDDEN
struct ctf_fs_ds_index *ctf_fs_ds_file_build_index(
                struct ctf_fs_ds_file *ds_file,
                struct ctf_fs_ds_file_info *file_info,
                struct ctf_msg_iter *msg_iter)
{
        struct ctf_fs_ds_index *index;
        bt_self_component *self_comp = ds_file->self_comp;
        bt_logging_level log_level = ds_file->log_level;

        index = build_index_from_idx_file(ds_file, file_info, msg_iter);
        if (index) {
                goto end;
        }

        BT_COMP_LOGI("Failed to build index from .index file; "
                "falling back to stream indexing.");
        index = build_index_from_stream_file(ds_file, file_info, msg_iter);
end:
        return index;
}

BT_HIDDEN
struct ctf_fs_ds_index *ctf_fs_ds_index_create(bt_logging_level log_level,
                bt_self_component *self_comp)
{
        struct ctf_fs_ds_index *index = g_new0(struct ctf_fs_ds_index, 1);

        if (!index) {
                BT_COMP_LOG_CUR_LVL(BT_LOG_ERROR, log_level, self_comp,
                        "Failed to allocate index");
                goto error;
        }

        index->entries = g_ptr_array_new_with_free_func((GDestroyNotify) g_free);
        if (!index->entries) {
                BT_COMP_LOG_CUR_LVL(BT_LOG_ERROR, log_level, self_comp,
                        "Failed to allocate index entries.");
                goto error;
        }

        goto end;

error:
        ctf_fs_ds_index_destroy(index);
        index = NULL;
end:
        return index;
}

BT_HIDDEN
void ctf_fs_ds_file_destroy(struct ctf_fs_ds_file *ds_file)
{
        if (!ds_file) {
                return;
        }

        bt_stream_put_ref(ds_file->stream);
        (void) ds_file_munmap(ds_file);

        if (ds_file->file) {
                ctf_fs_file_destroy(ds_file->file);
        }

        g_free(ds_file);
}

BT_HIDDEN
void ctf_fs_ds_index_destroy(struct ctf_fs_ds_index *index)
{
        if (!index) {
                return;
        }

        if (index->entries) {
                g_ptr_array_free(index->entries, TRUE);
        }
        g_free(index);
}