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//==========================================================================

//

//      e2fs.c

//

//      RedBoot support for second extended filesystem

//

//==========================================================================

// ####ECOSGPLCOPYRIGHTBEGIN####                                            

// -------------------------------------------                              

// This file is part of eCos, the Embedded Configurable Operating System.   

// Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2008 Free Software Foundation, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under    

// the terms of the GNU General Public License as published by the Free     

// Software Foundation; either version 2 or (at your option) any later      

// version.                                                                 

//

// eCos 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 eCos; if not, write to the Free Software Foundation, Inc.,    

// 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.            

//

// As a special exception, if other files instantiate templates or use      

// macros or inline functions from this file, or you compile this file      

// and link it with other works to produce a work based on this file,       

// this file does not by itself cause the resulting work to be covered by   

// the GNU General Public License. However the source code for this file    

// must still be made available in accordance with section (3) of the GNU   

// General Public License v2.                                               

//

// This exception does not invalidate any other reasons why a work based    

// on this file might be covered by the GNU General Public License.         

// -------------------------------------------                              

// ####ECOSGPLCOPYRIGHTEND####                                              

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    msalter

// Contributors: msalter

// Date:         2001-07-14

// Purpose:      

// Description:  

//              

// This code is part of RedBoot (tm).

//

//####DESCRIPTIONEND####

//

//==========================================================================

#include <redboot.h>

#include <fs/disk.h>

#include <fs/e2fs.h>

#define DEBUG_E2FS 0

#if DEBUG_E2FS > 4

static void dump_sb(struct e2fs_super_block *s);

static void dump_inode(struct e2fs_inode *i);

#endif

static void *e2fs_open(partition_t *p, const char *path);

static int  e2fs_read(void *fp, char *buf, cyg_uint32 nbytes);

// This structure is the only thing exported by this module.

// These filesystem function pointers are attached to disk

// partitions in the generic disk handling code.

//

fs_funs_t redboot_e2fs_funs = {

    e2fs_open,

    e2fs_read

};

// A single block buffer to be shared carefully.

static cyg_uint32 blockbuf[E2FS_MAX_BLOCK_SIZE/sizeof(cyg_uint32)];

#define __READ_BLOCK(n)                                          \

  PARTITION_READ(e2fs->part, E2FS_BLOCK_TO_SECTOR(e2fs, (n)),    \

                      blockbuf, e2fs->blocksize/SECTOR_SIZE)

// Get a group descriptor. Returns non-zero for success.

//

static int

e2fs_get_gdesc(e2fs_desc_t *e2fs, cyg_uint32 group_nr, e2fs_group_t *gdesc)

{

    cyg_uint32 sec_nr;

    if (group_nr < e2fs->gdesc_first ||

        group_nr >= (e2fs->gdesc_first + E2FS_GDESC_CACHE_SIZE)) {

        // cache miss

        sec_nr = E2FS_BLOCK_TO_SECTOR(e2fs, e2fs->gdesc_block);

        sec_nr += (group_nr / E2FS_GDESC_PER_SECTOR);

#if DEBUG_E2FS > 2

        diag_printf("%s: group[%d] cache miss, sec_nr[%d]\n",

                    __FUNCTION__, group_nr, sec_nr);

#endif

        if (!PARTITION_READ(e2fs->part, sec_nr, (cyg_uint32 *)e2fs->gdesc_cache,

                            sizeof(e2fs->gdesc_cache)/SECTOR_SIZE))

            return 0;

        e2fs->gdesc_first = (group_nr / E2FS_GDESC_CACHE_SIZE) * E2FS_GDESC_CACHE_SIZE;

    }

    *gdesc = e2fs->gdesc_cache[group_nr - e2fs->gdesc_first];

    return 1;

}

// Read the requested inode from disk. Return non-zero if successful

//

static int

e2fs_get_inode(e2fs_desc_t *e2fs, int ino, e2fs_inode_t *ip)

{

    cyg_uint32 offset, sec_nr, buf[SECTOR_SIZE/sizeof(cyg_uint32)];

    e2fs_group_t gdesc;

    // get descriptor for group which this inode belongs to

    if (!e2fs_get_gdesc(e2fs, (ino - 1) / e2fs->inodes_per_group, &gdesc))

        return 0;

    if (gdesc.inode_table == 0)

        return 0;

    // byte offset within group inode table

    offset = ((ino - 1) % e2fs->inodes_per_group) * sizeof(struct e2fs_inode);

    // figure out which sector holds the inode

    sec_nr = E2FS_BLOCK_TO_SECTOR(e2fs, SWAB_LE32(gdesc.inode_table));

    sec_nr += offset / SECTOR_SIZE;

    // and the offset within that sector.

    offset %= SECTOR_SIZE;

#if DEBUG_E2FS > 0x08

    diag_printf("%s: ino[%d], sec_nr[%d] offset[%d]\n", __FUNCTION__,

                ino, sec_nr, offset);

#endif

    if (!PARTITION_READ(e2fs->part, sec_nr, buf, 1))

        return 0;

    *ip = *(e2fs_inode_t *)((char *)buf + offset);

#if DEBUG_E2FS > 0

    diag_printf("%s: inode size[%d]\n", __FUNCTION__, SWAB_LE32(ip->size));

#endif

    return 1;

}

// Mount an e2fs filesystem on the given partition.

// Return 0 if successful.

//

static int

e2fs_mount(partition_t *part, e2fs_desc_t *e2fs)

{

    int sb_block = 1;

    union {

        cyg_uint32  sb_buf[E2FS_MIN_BLOCK_SIZE/sizeof(cyg_uint32)];

        struct e2fs_super_block sbdata;

    } sbdata_union;

    struct e2fs_super_block *sb=&sbdata_union.sbdata;

    e2fs->part = part;

    if (!PARTITION_READ(part, sb_block*(E2FS_MIN_BLOCK_SIZE/SECTOR_SIZE),

                        &sbdata_union.sb_buf[0], E2FS_MIN_BLOCK_SIZE/SECTOR_SIZE))

        return -1;

    if (SWAB_LE16(sb->magic) != E2FS_SUPER_MAGIC) {

        diag_printf("ext2_mount: bad magic 0x%x\n", SWAB_LE16(sb->magic));

        return -1;

    }

    // save some stuff for easy access

    e2fs->blocksize = E2FS_BLOCK_SIZE(sb);

    e2fs->nr_ind_blocks = (e2fs)->blocksize / sizeof(cyg_uint32);

    e2fs->nr_dind_blocks = e2fs->nr_ind_blocks * ((e2fs)->blocksize / sizeof(cyg_uint32));

    e2fs->nr_tind_blocks = e2fs->nr_dind_blocks * ((e2fs)->blocksize / sizeof(cyg_uint32));

    e2fs->blocks_per_group = SWAB_LE32(sb->blocks_per_group);

    e2fs->ngroups = (SWAB_LE32(sb->blocks_count) + e2fs->blocks_per_group - 1) /

                     e2fs->blocks_per_group;

    e2fs->inodes_per_group = SWAB_LE32(sb->inodes_per_group);

    // Find the group descriptors which follow superblock

    e2fs->gdesc_block = ((sb_block * E2FS_MIN_BLOCK_SIZE) / e2fs->blocksize) + 1;

    e2fs->gdesc_first = 0; // cache group 0 initially

    if (!PARTITION_READ(part, E2FS_BLOCK_TO_SECTOR(e2fs,e2fs->gdesc_block),

                        (cyg_uint32 *)e2fs->gdesc_cache, 1))

        return -1;

#if DEBUG_E2FS > 1

    diag_printf("E2FS superblock:\n");

    diag_printf("   [%d] inodes\n", SWAB_LE32(sb->inodes_count));

    diag_printf("   [%d] blocks\n", SWAB_LE32(sb->blocks_count));

    diag_printf("   [%d] blocksize\n", e2fs->blocksize);

    diag_printf("   [%d] blocks per group\n", e2fs->blocks_per_group);

    diag_printf("   [%d] ngroups\n", e2fs->ngroups);

#endif

#if DEBUG_E2FS > 4

    dump_sb(sb);

#endif

    return 0;

}

// Convert a block index into inode data into a block_nr.

// If successful, store block number in pblknr and return non-zero.

//

// NB: This needs some block/sector caching to be speedier. But

//     that takes memory and speed is not too bad now for files

//     small enough to avoid double and triple indirection.

//

static int

e2fs_inode_block(e2fs_desc_t *e2fs, e2fs_inode_t *inode,

                 cyg_uint32 bindex, cyg_uint32 *pblknr)

{

    if (bindex < E2FS_NR_DIR_BLOCKS) {

        *pblknr = SWAB_LE32(inode->block[bindex]);

        return 1;

    }

    bindex -= E2FS_NR_DIR_BLOCKS;

    if (bindex < e2fs->nr_ind_blocks) {

        // Indirect block

        if (!__READ_BLOCK(SWAB_LE32(inode->block[E2FS_IND_BLOCK])))

            return 0;

        *pblknr = SWAB_LE32(blockbuf[bindex]);

        return 1;

    }

    bindex -= e2fs->nr_ind_blocks;

    if (bindex < e2fs->nr_dind_blocks) {

        // Double indirect block

        if (!__READ_BLOCK(SWAB_LE32(inode->block[E2FS_DIND_BLOCK])))

            return 0;

        if (!__READ_BLOCK(SWAB_LE32(blockbuf[bindex / e2fs->nr_ind_blocks])))

            return 0;

        *pblknr  = SWAB_LE32(blockbuf[bindex % e2fs->nr_ind_blocks]);

        return 1;

    }

    bindex -= e2fs->nr_dind_blocks;

    // Triple indirect block

    if (!__READ_BLOCK(SWAB_LE32(inode->block[E2FS_TIND_BLOCK])))

        return 0;

    if (!__READ_BLOCK(SWAB_LE32(blockbuf[bindex / e2fs->nr_dind_blocks])))

        return 0;

    bindex %= e2fs->nr_dind_blocks;

    if (!__READ_BLOCK(SWAB_LE32(blockbuf[bindex / e2fs->nr_ind_blocks])))

        return 0;

    *pblknr = SWAB_LE32(blockbuf[bindex % e2fs->nr_ind_blocks]);

    return 1;

}

// search a single directory block in memory looking for an

// entry with the given name. Return pointer to entry if

// found, NULL if not.

//

static e2fs_dir_entry_t *

search_dir_block(e2fs_desc_t *e2fs, cyg_uint32 *blkbuf,

                 const char *name, int namelen)

{

    e2fs_dir_entry_t *dir;

    cyg_uint16 reclen, len;

    cyg_uint32 offset;

#if DEBUG_E2FS > 0

    diag_dump_buf(blkbuf, e2fs->blocksize);

#endif

    offset = 0;

    while (offset < e2fs->blocksize) {

        dir = (e2fs_dir_entry_t *)((char *)blkbuf + offset);

        reclen = SWAB_LE16(dir->reclen);

        offset += reclen;

        len = dir->namelen;

        // terminate on anything which doesn't make sense

        if (reclen < 8 || (len + 8) > reclen || offset > (e2fs->blocksize + 1))

            return NULL;

        if (dir->inode && len == namelen && !strncmp(dir->name, name, len))

            return dir;

    }

    return NULL;

}

// Look in the given directory for an entry with the given name.

// If found, return a pointer to that entry. Return NULL if not

// found.

//

static e2fs_dir_entry_t *

e2fs_dir_lookup(e2fs_desc_t *e2fs, cyg_uint32  dir_ino,

                const char  *name, int         namelen)

{

    e2fs_inode_t inode;

    e2fs_dir_entry_t *dir;

    cyg_uint32 nblocks, last_block_size, i, block_nr, nbytes;

#if DEBUG_E2FS > 0

    diag_printf("%s: looking for %s [%d] in ino[%d]\n",

                __FUNCTION__, name, namelen, dir_ino);

#endif

    if (!e2fs_get_inode(e2fs, dir_ino, &inode)) {

#if DEBUG_E2FS > 0

        diag_printf("%s: e2fs_get_inode [%d] failed\n", __FUNCTION__, dir_ino);

#endif

        return NULL;

    }

    nbytes = SWAB_LE32(inode.size);

    nblocks = (nbytes + e2fs->blocksize - 1) / e2fs->blocksize;

    last_block_size = nbytes % e2fs->blocksize;

    if (last_block_size == 0)

        last_block_size = e2fs->blocksize;

    for (i = 0; i < nblocks; i++) {

        if (!e2fs_inode_block(e2fs, &inode, i, &block_nr))

            return NULL;

        if (block_nr) {

            if (!__READ_BLOCK(block_nr))

                return NULL;

        } else

            memset(blockbuf, 0, e2fs->blocksize);

        dir = search_dir_block(e2fs, blockbuf, name, namelen);

        if (dir != NULL)

            return dir;

    }

    return NULL;

}

typedef struct ino_info {

    cyg_uint32  ino;

    cyg_uint32  parent_ino;

    cyg_uint8   filetype;

} ino_info_t;

static int e2fs_inode_lookup(e2fs_desc_t *e2fs, cyg_uint32 dir_ino,

                             const char *pathname, ino_info_t *info);

// Starting from the given directory, find the inode number, filetype, and

// parent inode for the file pointed to by the given symbolic link inode.

// If successful, fills out ino_info_t and return true.

//

static int

e2fs_follow_symlink(e2fs_desc_t *e2fs, cyg_uint32 dir_ino, cyg_uint32 sym_ino, ino_info_t *info)

{

#define MAX_SYMLINK_NAME 255

    char symlink[MAX_SYMLINK_NAME+1];

    int  pathlen;

    cyg_uint32 block_nr;

    e2fs_inode_t inode;

    if (!e2fs_get_inode(e2fs, sym_ino, &inode)) {

#if DEBUG_E2FS > 0

        diag_printf("%s: e2fs_get_inode [%d] failed\n", __FUNCTION__, sym_ino);

#endif

        return 0;

    }

    pathlen = SWAB_LE32(inode.size);

    if (pathlen > MAX_SYMLINK_NAME)

        return 0;

    if (inode.blocks) {

        if (!e2fs_inode_block(e2fs, &inode, 0, &block_nr))

            return 0;

        if (block_nr) {

            if (!PARTITION_READ(e2fs->part, E2FS_BLOCK_TO_SECTOR(e2fs, block_nr),

                                blockbuf, e2fs->blocksize/SECTOR_SIZE))

                return 0;

            memcpy(symlink, blockbuf, pathlen);

        } else

            return 0;

    } else {

        // small enough path to fit in inode struct

        memcpy(symlink, (char *)&inode.block[0], pathlen);

    }

    symlink[pathlen] = 0;

    return e2fs_inode_lookup(e2fs, dir_ino, symlink, info);

}

// Starting from the given directory, find the inode number, filetype, and

// parent inode for the given file pathname.

// If successful, fills out ino_info_t and return true.

//

static int

e2fs_inode_lookup(e2fs_desc_t *e2fs, cyg_uint32 dir_ino, const char *pathname, ino_info_t *info)

{

    int len, pathlen;

    const char *p;

    e2fs_dir_entry_t *dir = NULL;

    if (!pathname || (pathlen = strlen(pathname)) == 0)

        return 0;

    if (*pathname == '/') {

        if (--pathlen == 0) {

            info->ino = info->parent_ino = E2FS_ROOT_INO;

            info->filetype = E2FS_FTYPE_DIR;

            return 1;

        }

        ++pathname;

        dir_ino = E2FS_ROOT_INO;

    }

    while (pathlen) {

        // find next delimiter in path.

        for (p = pathname, len = 0; len < pathlen; len++, p++) {

            // skip delimiter if found.

            if (*p == '/') {

                ++p;

                --pathlen;

                break;

            }

        }

        dir = e2fs_dir_lookup(e2fs, dir_ino, pathname, len);

        if (dir == NULL)

            return 0;

        pathlen -= len;

        pathname = p;

        switch (dir->filetype) {

          case E2FS_FTYPE_SYMLINK:

            // follow the symbolic link (this will cause recursion)

            if (!e2fs_follow_symlink(e2fs, dir_ino, SWAB_LE32(dir->inode), info))

                return 0;

            if (pathlen == 0)

                return 1;

            // must be a dir if we want to continue

            if (info->filetype != E2FS_FTYPE_DIR)

                return 0;

            dir_ino = info->ino;

            break;

          case E2FS_FTYPE_DIR:

            if (pathlen)

                dir_ino = SWAB_LE32(dir->inode);

            break;

          case E2FS_FTYPE_REG_FILE:

            if (pathlen)

                return 0;  // regular file embedded in middle of path

            break;

          case E2FS_FTYPE_UNKNOWN:

          case E2FS_FTYPE_CHRDEV:

          case E2FS_FTYPE_BLKDEV:

          case E2FS_FTYPE_FIFO:

          case E2FS_FTYPE_SOCK:

          default:

            return 0;

        }

    }

    info->ino = SWAB_LE32(dir->inode);

    info->parent_ino = dir_ino;

    info->filetype = dir->filetype;

    return 1;

}

struct read_info {

    e2fs_desc_t  e2fs_desc;

    e2fs_inode_t inode;

    cyg_uint32   fsize;

    cyg_uint32   fpos;

};

static void *

e2fs_open(partition_t *p, const char *filepath)

{

    static struct read_info rinfo;

    ino_info_t    ino_info;

    // mount partition

    if (e2fs_mount(p, &rinfo.e2fs_desc) != 0) {

        diag_printf("mount failed.\n");

        return NULL;

    }

    // find file inode

    if (!e2fs_inode_lookup(&rinfo.e2fs_desc, E2FS_ROOT_INO, filepath, &ino_info)) {

        diag_printf("%s: e2fs_inode_lookup failed\n", __FUNCTION__);

        return NULL;

    }

    // read inode

    if (!e2fs_get_inode(&rinfo.e2fs_desc, ino_info.ino, &rinfo.inode)) {

        diag_printf("%s: e2fs_get_inode failed for ino[%d]\n", __FUNCTION__, ino_info.ino);

        return NULL;

    }

    rinfo.fsize = SWAB_LE32(rinfo.inode.size);

    rinfo.fpos  = 0;

    return &rinfo;

}

static int

e2fs_read(void *fp, char *buf, cyg_uint32 nbytes)

{

    struct read_info *info = fp;

    e2fs_desc_t *e2fs;

    cyg_uint32 nread = 0, rem, block_nr, bindex, to_read;

    if ((info->fpos + nbytes) > info->fsize)

        nbytes = info->fsize - info->fpos;

    e2fs = &info->e2fs_desc;

    // see if we need to copy leftover data from last read call

    rem = e2fs->blocksize - (info->fpos % e2fs->blocksize);

    if (rem != e2fs->blocksize) {

        char *p = (char *)blockbuf + e2fs->blocksize - rem;

        if (rem > nbytes)

            rem = nbytes;

        memcpy(buf, p, rem);

        nread += rem;

        buf  += rem;

        info->fpos += rem;

    }

    // now loop through blocks if we're not done

    bindex = info->fpos / e2fs->blocksize;

    while (nread < nbytes) {

        if (!e2fs_inode_block(e2fs, &info->inode, bindex, &block_nr))

            return -1;

        if (block_nr) {

            if (!PARTITION_READ(e2fs->part, E2FS_BLOCK_TO_SECTOR(e2fs, block_nr),

                                blockbuf, e2fs->blocksize/SECTOR_SIZE))

                return 0;

        } else

            memset(blockbuf, 0, e2fs->blocksize);

        to_read = nbytes - nread;

        if (to_read > e2fs->blocksize)

            to_read = e2fs->blocksize;

        memcpy(buf, blockbuf, to_read);

        nread += to_read;

        buf += to_read;

        info->fpos += to_read;

        ++bindex;

    }

    return nread;

}

#if DEBUG_E2FS > 4

static void dump_sb(struct e2fs_super_block *s)

{

    diag_printf("inode_count: %d\n", SWAB_LE32(s->inodes_count));

    diag_printf("blocks_count: %d\n", SWAB_LE32(s->blocks_count));

    diag_printf("r_blocks_count: %d\n", SWAB_LE32(s->r_blocks_count));

    diag_printf("free_blocks_count: %d\n", SWAB_LE32(s->free_blocks_count));

    diag_printf("free_inodes_count: %d\n", SWAB_LE32(s->free_inodes_count));

    diag_printf("first_data_block: %d\n", SWAB_LE32(s->first_data_block));

    diag_printf("log_block_size: %d\n", SWAB_LE32(s->log_block_size));

    diag_printf("log_frag_size: %d\n", SWAB_LE32(s->log_frag_size));

    diag_printf("blocks_per_group: %d\n", SWAB_LE32(s->blocks_per_group));

    diag_printf("frags_per_group: %d\n", SWAB_LE32(s->frags_per_group));

    diag_printf("inodes_per_group: %d\n", SWAB_LE32(s->inodes_per_group));

    diag_printf("mnt_count: %d\n", SWAB_LE16(s->mnt_count));

    diag_printf("max_mnt_count: %d\n", SWAB_LE16(s->max_mnt_count));

    diag_printf("magic: %d\n", SWAB_LE16(s->magic));

    diag_printf("state: %d\n", SWAB_LE16(s->state));

    diag_printf("errors: %d\n", SWAB_LE16(s->errors));

    diag_printf("minor_rev_level: %d\n", SWAB_LE16(s->minor_rev_level));

    diag_printf("lastcheck: %d\n", SWAB_LE32(s->lastcheck));

    diag_printf("checkinterval: %d\n", SWAB_LE32(s->checkinterval));

    diag_printf("creator_os: %d\n", SWAB_LE32(s->creator_os));

    diag_printf("rev_level: %d\n", SWAB_LE32(s->rev_level));

}

static void dump_inode(struct e2fs_inode *i)

{

    int j, n;

    diag_printf("mode: %o\n", SWAB_LE16(i->mode));

    diag_printf("uid: %o\n", SWAB_LE16(i->uid));

    diag_printf("size: %d\n", SWAB_LE32(i->size));

    diag_printf("gid: %o\n", SWAB_LE16(i->gid));

    diag_printf("links: %d\n", SWAB_LE16(i->links_count));

    diag_printf("blocks: %d\n", SWAB_LE32(i->blocks));

    n = i->blocks;

    if (n > E2FS_N_BLOCKS)

        n = E2FS_N_BLOCKS;

    for (j = 0; j < n; j++)

        diag_printf("  block: %d\n", SWAB_LE32(i->block[j]));

}

#endif