source: mainline/uspace/srv/fs/minixfs/mfs_ops.c@ b438804

/*
 * Copyright (c) 2011 Maurizio Lombardi
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup fs
 * @{
 */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <fibril_synch.h>
#include <errno.h>
#include "mfs.h"
#include "mfs_utils.h"

static bool check_magic_number(uint16_t magic, bool *native,
                                mfs_version_t *version, bool *longfilenames);
static int mfs_node_core_get(fs_node_t **rfn, struct mfs_instance *inst,
                        fs_index_t index);

static int mfs_node_put(fs_node_t *fsnode);
static int mfs_node_open(fs_node_t *fsnode);
static fs_index_t mfs_index_get(fs_node_t *fsnode);
static unsigned mfs_lnkcnt_get(fs_node_t *fsnode);
static char mfs_plb_get_char(unsigned pos);
static bool mfs_is_directory(fs_node_t *fsnode);
static bool mfs_is_file(fs_node_t *fsnode);
static int mfs_has_children(bool *has_children, fs_node_t *fsnode);
static int mfs_root_get(fs_node_t **rfn, devmap_handle_t handle);
static devmap_handle_t mfs_device_get(fs_node_t *fsnode);
static aoff64_t mfs_size_get(fs_node_t *node);

static
int mfs_node_get(fs_node_t **rfn, devmap_handle_t devmap_handle,
                        fs_index_t index);


static LIST_INITIALIZE(inst_list);
static FIBRIL_MUTEX_INITIALIZE(inst_list_mutex);

libfs_ops_t mfs_libfs_ops = {
        .size_get = mfs_size_get,
        .root_get = mfs_root_get,
        .device_get = mfs_device_get,
        .is_directory = mfs_is_directory,
        .is_file = mfs_is_file,
        .node_get = mfs_node_get,
        .node_put = mfs_node_put,
        .node_open = mfs_node_open,
        .index_get = mfs_index_get,
        .plb_get_char = mfs_plb_get_char,
        .has_children = mfs_has_children,
        .lnkcnt_get = mfs_lnkcnt_get
};

void mfs_mounted(ipc_callid_t rid, ipc_call_t *request)
{
        devmap_handle_t devmap_handle = (devmap_handle_t) IPC_GET_ARG1(*request);
        enum cache_mode cmode;  
        struct mfs_superblock *sb;
        struct mfs3_superblock *sb3;
        struct mfs_sb_info *sbi;
        struct mfs_instance *instance;
        bool native, longnames;
        mfs_version_t version;
        uint16_t magic;

        /* Accept the mount options */
        char *opts;
        int rc = async_data_write_accept((void **) &opts, true, 0, 0, 0, NULL);
        
        if (rc != EOK) {
                mfsdebug("Can't accept async data write\n");
                async_answer_0(rid, rc);
                return;
        }

        /* Check for option enabling write through. */
        if (str_cmp(opts, "wtcache") == 0)
                cmode = CACHE_MODE_WT;
        else
                cmode = CACHE_MODE_WB;

        free(opts);

        /* initialize libblock */
        rc = block_init(devmap_handle, 1024);
        if (rc != EOK) {
                mfsdebug("libblock initialization failed\n");
                async_answer_0(rid, rc);
                return;
        }

        /*Allocate space for generic MFS superblock*/
        sbi = malloc(sizeof(*sbi));

        if (!sbi) {
                async_answer_0(rid, ENOMEM);
                return;
        }

        /*Allocate space for filesystem instance*/
        instance = malloc(sizeof(*instance));

        if (!instance) {
                async_answer_0(rid, ENOMEM);
                return;
        }

        sb = malloc(MFS_SUPERBLOCK_SIZE);

        if (!sb) {
                async_answer_0(rid, ENOMEM);
                return;
        }

        /* Read the superblock */
        rc = block_read_direct(devmap_handle, MFS_SUPERBLOCK << 1, 1, sb);
        if (rc != EOK) {
                block_fini(devmap_handle);
                async_answer_0(rid, rc);
                return;
        }

        sb3 = (struct mfs3_superblock *) sb;

        if (check_magic_number(sb->s_magic, &native, &version, &longnames)) {
                /*This is a V1 or V2 Minix filesystem*/
                magic = sb->s_magic;
                goto recognized;
        }

        if (!check_magic_number(sb3->s_magic, &native, &version, &longnames)) {
                mfsdebug("magic number not recognized\n");
                block_fini(devmap_handle);
                async_answer_0(rid, ENOTSUP);
                return;
        }

        /*This is a V3 Minix filesystem*/

        magic = sb3->s_magic;

recognized:

        mfsdebug("magic number recognized = %04x\n", magic);

        /*Fill superblock info structure*/

        sbi->fs_version = version;
        sbi->long_names = longnames;
        sbi->native = native;
        sbi->magic = magic;
        sbi->isearch = 0;
        sbi->zsearch = 0;

        if (version == MFS_VERSION_V3) {
                sbi->ninodes = conv32(native, sb3->s_ninodes);
                sbi->ibmap_blocks = conv16(native, sb3->s_ibmap_blocks);
                sbi->zbmap_blocks = conv16(native, sb3->s_zbmap_blocks);
                sbi->firstdatazone = conv16(native, sb3->s_first_data_zone);
                sbi->log2_zone_size = conv16(native, sb3->s_log2_zone_size);
                sbi->max_file_size = conv32(native, sb3->s_max_file_size);
                sbi->nzones = conv32(native, sb3->s_nzones);
                sbi->block_size = conv16(native, sb3->s_block_size);
                sbi->dirsize = MFS3_DIRSIZE;
        } else {
                sbi->ninodes = conv16(native, sb->s_ninodes);
                sbi->ibmap_blocks = conv16(native, sb->s_ibmap_blocks);
                sbi->zbmap_blocks = conv16(native, sb->s_zbmap_blocks);
                sbi->firstdatazone = conv16(native, sb->s_first_data_zone);
                sbi->log2_zone_size = conv16(native, sb->s_log2_zone_size);
                sbi->max_file_size = conv32(native, sb->s_max_file_size);
                sbi->nzones = conv16(native, sb->s_nzones);
                sbi->block_size = MFS_BLOCKSIZE;
                if (version == MFS_VERSION_V2)
                        sbi->nzones = conv32(native, sb->s_nzones2);
                sbi->dirsize = longnames ? MFSL_DIRSIZE : MFS_DIRSIZE;
        }
 
        free(sb);

        rc = block_cache_init(devmap_handle, sbi->block_size, 0, CACHE_MODE_WT);

        if (rc != EOK) {
                block_fini(devmap_handle);
                async_answer_0(rid, EINVAL);
                mfsdebug("block cache initialization failed\n");
                return;
        }

        /*Initialize the instance structure and add it to the list*/
        link_initialize(&instance->link);
        instance->handle = devmap_handle;
        instance->sbi = sbi;

        fibril_mutex_lock(&inst_list_mutex);
        list_append(&instance->link, &inst_list);
        fibril_mutex_unlock(&inst_list_mutex);

        mfsdebug("mount successful\n");

        async_answer_0(rid, EOK);
}

void mfs_mount(ipc_callid_t rid, ipc_call_t *request)
{
        libfs_mount(&mfs_libfs_ops, mfs_reg.fs_handle, rid, request);
}

devmap_handle_t mfs_device_get(fs_node_t *fsnode)
{
        struct mfs_node *node = fsnode->data;
        return node->instance->handle;
}

static aoff64_t mfs_size_get(fs_node_t *node)
{
        assert(node);

        const struct mfs_node *mnode = node->data;
        assert(mnode);
        assert(mnode->ino_i);

        mfsdebug("inode size is %d\n", (int) mnode->ino_i->i_size);

        return mnode->ino_i->i_size;
}

void mfs_stat(ipc_callid_t rid, ipc_call_t *request)
{
        mfsdebug("mfs_stat()\n");
        libfs_stat(&mfs_libfs_ops, mfs_reg.fs_handle, rid, request);
}

static int mfs_node_get(fs_node_t **rfn, devmap_handle_t devmap_handle,
                        fs_index_t index)
{
        int rc;
        struct mfs_instance *instance;

        mfsdebug("mfs_node_get()\n");

        rc = mfs_instance_get(devmap_handle, &instance);

        if (rc != EOK)
                return rc;

        return mfs_node_core_get(rfn, instance, index);
}

static int mfs_node_put(fs_node_t *fsnode)
{
        struct mfs_node *mnode = fsnode->data;

        mfsdebug("mfs_node_put()\n");

        assert(mnode->ino_i);

        if (mnode->ino_i->dirty) {
                /*TODO: Write inode on disk*/
        }

        free(mnode->ino_i);
        free(mnode);

        return EOK;
}

static int mfs_node_open(fs_node_t *fsnode)
{
        /*
         * Opening a file is stateless, nothing
         * to be done here.
         */
        return EOK;
}

static fs_index_t mfs_index_get(fs_node_t *fsnode)
{
        struct mfs_node *mnode = fsnode->data;

        mfsdebug("mfs_index_get()\n");

        assert(mnode->ino_i);
        return mnode->ino_i->index;
}

static unsigned mfs_lnkcnt_get(fs_node_t *fsnode)
{
        unsigned rc;
        struct mfs_node *mnode = fsnode->data;

        assert(mnode);
        assert(mnode->ino_i);

        rc = mnode->ino_i->i_nlinks;
        mfsdebug("mfs_lnkcnt_get(): %u\n", rc);
        return rc;
}

static int mfs_node_core_get(fs_node_t **rfn, struct mfs_instance *inst,
                        fs_index_t index)
{
        fs_node_t *node = NULL;
        struct mfs_node *mnode = NULL;
        int rc;

        const struct mfs_sb_info *sbi = inst->sbi;

        node = malloc(sizeof(fs_node_t));
        if (!node) {
                rc = ENOMEM;
                goto out_err;
        }

        fs_node_initialize(node);

        mnode = malloc(sizeof(*mnode));
        if (!mnode) {
                rc = ENOMEM;
                goto out_err;
        }

        struct mfs_ino_info *ino_i;

        if (sbi->fs_version == MFS_VERSION_V1) {
                /*Read MFS V1 inode*/
                ino_i = mfs_read_inode_raw(inst, index);
        } else {
                /*Read MFS V2/V3 inode*/
                ino_i = mfs2_read_inode_raw(inst, index);
        }

        if (!ino_i)
                goto out_err;

        ino_i->index = index;
        mnode->ino_i = ino_i;

        mnode->instance = inst;
        node->data = mnode;
        *rfn = node;

        mfsdebug("node_get_core(%d) OK\n", (int) index);

        return EOK;

out_err:
        if (node)
                free(node);
        if (mnode)
                free(mnode);
        return rc;
}

static bool mfs_is_directory(fs_node_t *fsnode)
{
        const struct mfs_node *node = fsnode->data;
        return S_ISDIR(node->ino_i->i_mode);
}

static bool mfs_is_file(fs_node_t *fsnode)
{
        struct mfs_node *node = fsnode->data;
        return S_ISREG(node->ino_i->i_mode);
}

static int mfs_root_get(fs_node_t **rfn, devmap_handle_t handle)
{
        int rc = mfs_node_get(rfn, handle, MFS_ROOT_INO);

        mfsdebug("mfs_root_get %s\n", rc == EOK ? "OK" : "FAIL");
        return rc;
}

void mfs_lookup(ipc_callid_t rid, ipc_call_t *request)
{
        libfs_lookup(&mfs_libfs_ops, mfs_reg.fs_handle, rid, request);
}

static char mfs_plb_get_char(unsigned pos)
{
        return mfs_reg.plb_ro[pos % PLB_SIZE];
}

static int mfs_has_children(bool *has_children, fs_node_t *fsnode)
{
        struct mfs_node *mnode = fsnode->data;
        const struct mfs_ino_info *ino_i = mnode->ino_i;
        const struct mfs_instance *inst = mnode->instance;
        const struct mfs_sb_info *sbi = inst->sbi;
        uint32_t n_dentries = 0;

        *has_children = false;

        if (!S_ISDIR(mnode->ino_i->i_mode))
                goto out;

        struct mfs_dentry_info *d_info;
        n_dentries =  ino_i->i_size / sbi->dirsize;
        
        /* The first two dentries are always . and .. */
        assert(n_dentries >= 2);

        if (n_dentries == 2)
                goto out;

        int i = 2;
        while (1) {
                d_info = read_directory_entry(mnode, i++);

                if (!d_info) {
                        /*Reached the end of the dentries list*/
                        break;
                }

                if (d_info->d_inum) {
                        /*A valid entry has been found*/
                        *has_children = true;
                        free(d_info);
                        break;
                }

                free(d_info);
        }

out:

        if (n_dentries > 2 && !*has_children)
                printf(NAME ": Filesystem corruption detected\n");

        if (*has_children)
                mfsdebug("Has children\n");
        else
                mfsdebug("Has not children\n");

        return EOK;
}

/*
 * Find a filesystem instance given the devmap handle
 */
int mfs_instance_get(devmap_handle_t handle, struct mfs_instance **instance)
{
        link_t *link;
        struct mfs_instance *instance_ptr;

        fibril_mutex_lock(&inst_list_mutex);

        for (link = inst_list.next; link != &inst_list; link = link->next) {
                instance_ptr = list_get_instance(link, struct mfs_instance, link);
                
                if (instance_ptr->handle == handle) {
                        *instance = instance_ptr;
                        fibril_mutex_unlock(&inst_list_mutex);
                        return EOK;
                }
        }

        mfsdebug("Instance not found\n");

        fibril_mutex_unlock(&inst_list_mutex);
        return EINVAL;
}

static bool check_magic_number(uint16_t magic, bool *native,
                                mfs_version_t *version, bool *longfilenames)
{
        bool rc = false;
        *longfilenames = false;

        if (magic == MFS_MAGIC_V1 || magic == MFS_MAGIC_V1R) {
                *native = magic == MFS_MAGIC_V1;
                *version = MFS_VERSION_V1;
                rc = true;
        } else if (magic == MFS_MAGIC_V1L || magic == MFS_MAGIC_V1LR) {
                *native = magic == MFS_MAGIC_V1L;
                *version = MFS_VERSION_V1;
                *longfilenames = true;
                rc = true;
        } else if (magic == MFS_MAGIC_V2 || magic == MFS_MAGIC_V2R) {
                *native = magic == MFS_MAGIC_V2;
                *version = MFS_VERSION_V2;
                rc = true;
        } else if (magic == MFS_MAGIC_V2L || magic == MFS_MAGIC_V2LR) {
                *native = magic == MFS_MAGIC_V2L;
                *version = MFS_VERSION_V2;
                *longfilenames = true;
                rc = true;
        } else if (magic == MFS_MAGIC_V3 || magic == MFS_MAGIC_V3R) {
                *native = magic == MFS_MAGIC_V3;
                *version = MFS_VERSION_V3;
                rc = true;
        }

        return rc;
}

/**
 * @}
 */