Start implementation of IsoFilesystem for reading ISO images.
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Vreixo Formoso
310
src/fs_image.c
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310
src/fs_image.c
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/*
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* Copyright (c) 2007 Vreixo Formoso
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*
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* This file is part of the libisofs project; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation. See COPYING file for details.
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*/
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/*
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* Filesystem/FileSource implementation to access an ISO image, using an
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* IsoDataSource to read image data.
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*/
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#include "fs_image.h"
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#include "error.h"
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#include "ecma119.h"
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#include <stdlib.h>
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#include <string.h>
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/**
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* Should the RR extensions be read?
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*/
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enum read_rr_ext {
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RR_EXT_NO = 0, /*< Do not use RR extensions */
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RR_EXT_110 = 1, /*< RR extensions conforming version 1.10 */
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RR_EXT_112 = 2 /*< RR extensions conforming version 1.12 */
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};
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/**
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* Private data for the image IsoFilesystem
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*/
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typedef struct
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{
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/** DataSource from where data will be read */
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IsoDataSource *src;
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/**
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* Counter of the times the filesystem has been openned still pending of
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* close. It is used to keep track of when we need to actually open or
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* close the IsoDataSource.
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*/
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unsigned int open_count;
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uid_t uid; /**< Default uid when no RR */
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gid_t gid; /**< Default uid when no RR */
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mode_t mode; /**< Default mode when no RR (only permissions) */
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struct libiso_msgs *messenger;
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char *input_charset; /**< Input charset for RR names */
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/**
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* Will be filled with the block lba of the extend for the root directory,
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* as read from the PVM
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*/
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uint32_t iso_root_block;
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/**
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* If we need to read RR extensions. i.e., if the image contains RR
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* extensions, and the user wants to read them.
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*/
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enum read_rr_ext rr;
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/**
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* The function used to read the name from a directoy record. For ISO,
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* the name is in US-ASCII. For Joliet, in UCS-2BE. Thus, we need
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* different functions for both.
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*/
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char *(*get_name)(const char *, size_t);
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/**
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* Joliet and RR version 1.10 does not have file serial numbers,
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* we need to generate it. TODO what is this for?!?!?!
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*/
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//ino_t ino;
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/**
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* Bytes skipped within the System Use field of a directory record, before
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* the beginning of the SUSP system user entries. See IEEE 1281, SUSP. 5.3.
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*/
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uint8_t len_skp;
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/* Volume attributes */
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char *volset_id;
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char *volume_id; /**< Volume identifier. */
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char *publisher_id; /**< Volume publisher. */
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char *data_preparer_id; /**< Volume data preparer. */
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char *system_id; /**< Volume system identifier. */
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char *application_id; /**< Volume application id */
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char *copyright_file_id;
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char *abstract_file_id;
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char *biblio_file_id;
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/* extension information */
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/**
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* RR version being used in image.
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* 0 no RR extension, 1 RRIP 1.10, 2 RRIP 1.12
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*/
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unsigned int rr_version : 2;
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/**
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* Number of blocks of the volume, as reported in the PVM.
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*/
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uint32_t nblocks;
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//TODO el-torito information
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} _ImageFsData;
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static
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int ifs_fs_open(IsoImageFilesystem *fs)
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{
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_ImageFsData *data;
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if (fs == NULL || fs->fs.data == NULL) {
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return ISO_NULL_POINTER;
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}
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data = (_ImageFsData*)fs->fs.data;
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if (data->open_count == 0) {
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/* we need to actually open the data source */
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int res = data->src->open(data->src);
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if (res < 0) {
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return res;
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}
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}
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++data->open_count;
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return ISO_SUCCESS;
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}
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static
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int ifs_fs_close(IsoImageFilesystem *fs)
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{
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_ImageFsData *data;
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if (fs == NULL || fs->fs.data == NULL) {
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return ISO_NULL_POINTER;
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}
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data = (_ImageFsData*)fs->fs.data;
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if (--data->open_count == 0) {
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/* we need to actually close the data source */
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return data->src->close(data->src);
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}
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return ISO_SUCCESS;
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}
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static
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void ifs_fs_free(IsoFilesystem *fs)
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{
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IsoImageFilesystem *ifs;
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_ImageFsData *data;
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ifs = (IsoImageFilesystem*)fs;
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data = (_ImageFsData*) fs->data;
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/* close data source if already openned */
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if (data->open_count > 0) {
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data->src->close(data->src);
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}
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/* free our ref to datasource */
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iso_data_source_unref(data->src);
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/* free volume atts */
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free(data->volset_id);
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free(data->volume_id);
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free(data->publisher_id);
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free(data->data_preparer_id);
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free(data->system_id);
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free(data->application_id);
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free(data->copyright_file_id);
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free(data->abstract_file_id);
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free(data->biblio_file_id);
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free(data->input_charset);
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free(data);
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}
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static
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int read_pvm(_ImageFsData *data, uint32_t block)
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{
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int ret;
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struct ecma119_pri_vol_desc *pvm;
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struct ecma119_dir_record *rootdr;
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unsigned char buffer[BLOCK_SIZE];
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/* read PVM */
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ret = data->src->read_block(data->src, block, buffer);
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if (ret < 0) {
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return ret;
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}
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pvm = (struct ecma119_pri_vol_desc *)buffer;
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/* sanity checks */
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if (pvm->vol_desc_type[0] != 1 || pvm->vol_desc_version[0] != 1
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|| strncmp((char*)pvm->std_identifier, "CD001", 5)
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|| pvm->file_structure_version[0] != 1 ) {
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return ISO_WRONG_PVD;
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}
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/* ok, it is a valid PVD */
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/* fill volume attributes */
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data->volset_id = strcopy((char*)pvm->vol_set_id, 128);
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data->volume_id = strcopy((char*)pvm->volume_id, 32);
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data->publisher_id = strcopy((char*)pvm->publisher_id, 128);
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data->data_preparer_id = strcopy((char*)pvm->data_prep_id, 128);
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data->system_id = strcopy((char*)pvm->system_id, 32);
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data->application_id = strcopy((char*)pvm->application_id, 128);
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data->copyright_file_id = strcopy((char*)pvm->copyright_file_id, 37);
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data->abstract_file_id = strcopy((char*)pvm->abstract_file_id, 37);
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data->biblio_file_id = strcopy((char*)pvm->bibliographic_file_id, 37);
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data->nblocks = iso_read_bb(pvm->vol_space_size, 4, NULL);
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rootdr = (struct ecma119_dir_record*) pvm->root_dir_record;
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data->iso_root_block = iso_read_bb(rootdr->block, 4, NULL);
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/*
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* TODO
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* PVM has other things that could be interesting, but that don't have a
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* member in IsoImage, such as creation date. In a multisession disc, we
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* could keep the creation date and update the modification date, for
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* example.
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*/
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return ISO_SUCCESS;
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}
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int iso_image_filesystem_new(IsoDataSource *src, struct iso_read_opts *opts,
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IsoImageFilesystem **fs)
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{
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int ret;
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IsoImageFilesystem *ifs;
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_ImageFsData *data;
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if (src == NULL || opts == NULL || fs == NULL) {
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return ISO_NULL_POINTER;
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}
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data = calloc(1, sizeof(_ImageFsData));
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if (data == NULL) {
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return ISO_MEM_ERROR;
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}
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ifs = calloc(1, sizeof(IsoImageFilesystem));
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if (ifs == NULL) {
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free(data);
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return ISO_MEM_ERROR;
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}
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/* get our ref to IsoDataSource */
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data->src = src;
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iso_data_source_ref(src);
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data->open_count = 0; //TODO
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/* fill data from opts */
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data->gid = opts->gid;
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data->uid = opts->uid;
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data->mode = opts->mode & ~S_IFMT;
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data->input_charset = strdup("UTF-8"); //TODO strdup(opts->input_charset);
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data->messenger = opts->messenger;
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ifs->open = ifs_fs_open;
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ifs->close = ifs_fs_close;
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ifs->fs.data = data;
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ifs->fs.free = ifs_fs_free;
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/* read Volume Descriptors and ensure it is a valid image */
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/* 1. first, open the filesystem */
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ifs_fs_open(ifs);
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/* 2. read primary volume description */
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ret = read_pvm(data, opts->block + 16);
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if (ret < 0) {
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goto fs_cleanup;
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}
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/* 3. read next volume descriptors */
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// TODO
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/* 4. check if RR extensions are being used */
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//TODO
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//ret = read_root_susp_entries(info, volume->root, data->iso_root_block);
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if (ret < 0) {
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return ret;
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}
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/* select what tree to read */
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//TODO
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/* and finally return. Note that we keep the DataSource opened */
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*fs = ifs;
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return ISO_SUCCESS;
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fs_cleanup: ;
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ifs_fs_free((IsoFilesystem*)ifs);
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free(ifs);
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return ret;
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}
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