common/fs/pcfs.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * Basic file system reading code for standalone I/O system.
 * Simulates a primitive UNIX I/O system (read(), write(), open(), etc).
 * Does not support writes.
 */

/*
 * WARNING:
 * This is currently used by installgrub for creating bootable floppy.
 * The special part is diskread_callback/fileread_callback for gathering
 * fileblock list.
 */

#include <sys/param.h>
#include <sys/sysmacros.h>
#include <sys/vnode.h>
#include <sys/fs/pc_label.h>
#include <sys/bootvfs.h>
#include <sys/filep.h>
#include "pcfilep.h"

#if defined(_BOOT)
#include "../common/util.h"
#elif   defined(_KERNEL)
#include <sys/sunddi.h>
#else
#include <stdio.h>
#include <strings.h>
#include <ctype.h>
#endif

#if defined(_BOOT)
#define dprintf if (bootrd_debug) printf
#elif   defined(_KERNEL)
#define printf  kobj_printf
#define dprintf if (bootrd_debug) kobj_printf

/* PRINTLIKE */
extern void kobj_printf(char *, ...);
#else
#define dprintf if (bootrd_debug) printf
#endif

#define FI_STARTCLUST(fp)   (*(ushort_t *)(fp)->fi_buf)
#define FI_LENGTH(fp)       (*(long *)((fp)->fi_buf + 4))

extern int bootrd_debug;
extern void *bkmem_alloc(size_t);
extern void bkmem_free(void *, size_t);

/*
 * NOTE: The fileread_callback is set by the calling program
 * during a file read. diskread_callback is set to fileread_callback
 * only if reading a file block. It needs to be NULL while reading
 * cluster blocks.
 */
extern int (*diskread_callback)(int, int);
extern int (*fileread_callback)(int, int);

/*
 *  Local prototypes
 */
static int lookuppn(char *, _dir_entry_p);
static fileid_t *find_fp(int);
static void *readblock(int, int);
static int fat_map(int, int);
static int cluster_valid(long, int);
static int fat_ctodb(int, int);

static int bpcfs_mountroot(char *str);
static int bpcfs_unmountroot(void);
static int bpcfs_open(char *str, int flags);
static int bpcfs_close(int fd);
static void bpcfs_closeall(void);
static ssize_t bpcfs_read(int fdesc, char *buf, size_t count);
static off_t bpcfs_lseek(int fdesc, off_t addr, int whence);

static fileid_t *head;
static _fat_controller_p pcfsp;

/* cache the cluster */
static int nsec_cache;
static int nsec_start;
static char *cluster_cache;

/*ARGSUSED*/
static int
bpcfs_mountroot(char *str)
{
    int ncluster;
    if (pcfsp != NULL)
        return (0); /* already mounted */

    pcfsp = bkmem_alloc(sizeof (_fat_controller_t));
    head = (fileid_t *)bkmem_alloc(sizeof (fileid_t));
    head->fi_back = head->fi_forw = head;
    head->fi_filedes = 0;
    head->fi_taken = 0;

    /* read of first floppy sector */
    head->fi_blocknum = 0;
    head->fi_count = SECSIZ;
    head->fi_memp = (caddr_t)pcfsp->f_sector;
    if (diskread(head)) {
        printf("failed to read first sector\n");
        bkmem_free(pcfsp, sizeof (*pcfsp));
        pcfsp = NULL;
        return (-1);
    }

    if (pcfsp->f_bpb.bs_spc == 0) {
        printf("invalid bios paramet block\n");
        return (-1);
    }

    pcfsp->f_rootsec =
        (pcfsp->f_bpb.bs_num_fats * ltohs(pcfsp->f_bpb.bs_spf)) +
        ltohs(pcfsp->f_bpb.bs_resv_sectors);
    pcfsp->f_rootlen =
        ltohs(pcfsp->f_bpb.bs_num_root_entries) *
        sizeof (_dir_entry_t) / SECSIZ;
    pcfsp->f_adjust = 0;
    pcfsp->f_dclust = CLUSTER_ROOTDIR;
    pcfsp->f_filesec = pcfsp->f_rootsec + pcfsp->f_rootlen;
    pcfsp->f_nxtfree = CLUSTER_FIRST;

    /* figure out the number of clusters in this partition */
    ncluster = (((ulong_t)ltohs(pcfsp->f_bpb.bs_siv) ?
        (ulong_t)ltohs(pcfsp->f_bpb.bs_siv) :
        (ulong_t)ltohi(pcfsp->f_bpb.bs_siv)) -
        pcfsp->f_filesec) / (ulong_t)pcfsp->f_bpb.bs_spc;
    pcfsp->f_16bit = ncluster >= CLUSTER_MAX_12;
    pcfsp->f_ncluster = ncluster;

    /* cache the cluster */
    if (pcfsp->f_16bit)
        nsec_cache = (((ncluster << 1) + 511) >> 9);
    else
        nsec_cache = (ncluster + ((ncluster + 1) >> 1) + 511) >> 9;
    cluster_cache = bkmem_alloc(nsec_cache * SECSIZ);
    if (cluster_cache == NULL) {
        printf("bpcfs_mountroot: out of memory\n");
        bkmem_free(pcfsp, sizeof (*pcfsp));
        pcfsp = NULL;
        return (-1);
    }

    head->fi_blocknum = nsec_start =
        ltohs(pcfsp->f_bpb.bs_resv_sectors) + pcfsp->f_adjust;
    head->fi_count = nsec_cache * SECSIZ;
    head->fi_memp = cluster_cache;
    if (diskread(head)) {
        printf("bpcfs_mountroot: failed to read cluster\n");
        bkmem_free(pcfsp, sizeof (*pcfsp));
        pcfsp = NULL;
        return (-1);
    }
    dprintf("read cluster sectors %d starting at %d\n",
        nsec_cache, nsec_start);
    return (0);
}

static int
bpcfs_unmountroot(void)
{
    if (pcfsp == NULL)
        return (-1);

    (void) bpcfs_closeall();

    return (0);
}

/*
 * Open a file.
 */
/*ARGSUSED*/
int
bpcfs_open(char *str, int flags)
{
    static int filedes = 1;

    fileid_t *filep;
    _dir_entry_t d;

    dprintf("open %s\n", str);
    filep = (fileid_t *)bkmem_alloc(sizeof (fileid_t));
    filep->fi_back = head->fi_back;
    filep->fi_forw = head;
    head->fi_back->fi_forw = filep;
    head->fi_back = filep;
    filep->fi_filedes = filedes++;
    filep->fi_taken = 1;
    filep->fi_path = (char *)bkmem_alloc(strlen(str) + 1);
    (void) strcpy(filep->fi_path, str);

    if (lookuppn(str, &d)) {
        (void) bpcfs_close(filep->fi_filedes);
        return (-1);
    }

    filep->fi_offset = 0;
    FI_STARTCLUST(filep) = d.d_cluster;
    FI_LENGTH(filep) = d.d_size;
    dprintf("file %s size = %ld\n", str, d.d_size);
    return (filep->fi_filedes);
}

int
bpcfs_close(int fd)
{
    fileid_t *filep;

    dprintf("close %d\n", fd);
    if (!(filep = find_fp(fd)))
        return (-1);

    if (filep->fi_taken == 0 || filep == head) {
        printf("File descripter %d no allocated!\n", fd);
        return (-1);
    }

    /* unlink and deallocate node */
    filep->fi_forw->fi_back = filep->fi_back;
    filep->fi_back->fi_forw = filep->fi_forw;
    bkmem_free(filep->fi_path, strlen(filep->fi_path) + 1);
    bkmem_free((char *)filep, sizeof (fileid_t));
    dprintf("close done\n");
    return (0);
}

static void
bpcfs_closeall(void)
{
    fileid_t *filep;

    while ((filep = head->fi_forw) != head)
        if (filep->fi_taken && bpcfs_close(filep->fi_filedes))
            printf("Filesystem may be inconsistent.\n");

    bkmem_free(pcfsp, sizeof (*pcfsp));
    bkmem_free(head, sizeof (fileid_t));
    pcfsp = NULL;
    head = NULL;
}

static ssize_t
bpcfs_read(int fd, caddr_t b, size_t c)
{
    ulong_t sector;
    uint_t count = 0, xfer, i;
    char *block;
    ulong_t off, blk;
    int rd, spc;
    fileid_t *fp;

    dprintf("bpcfs_read: fd = %d, buf = %p, size = %d\n",
        fd, (void *)b, c);
    fp = find_fp(fd);
    if (fp == NULL) {
        printf("invalid file descriptor %d\n", fd);
        return (-1);
    }

    spc = pcfsp->f_bpb.bs_spc;
    off = fp->fi_offset;
    blk = FI_STARTCLUST(fp);
    rd = blk == CLUSTER_ROOTDIR ? 1 : 0;

    spc = pcfsp->f_bpb.bs_spc;
    off = fp->fi_offset;
    blk = FI_STARTCLUST(fp);
    rd = (blk == CLUSTER_ROOTDIR) ? 1 : 0;

    if ((c = MIN(FI_LENGTH(fp) - off, c)) == 0)
        return (0);

    while (off >= pcfsp->f_bpb.bs_spc * SECSIZ) {
        blk = fat_map(blk, rd);
        off -= pcfsp->f_bpb.bs_spc * SECSIZ;

        if (!cluster_valid(blk, rd)) {
            printf("bpcfs_read: invalid cluster: %ld, %d\n",
                blk, rd);
            return (-1);
        }
    }

    while (count < c) {
        sector = fat_ctodb(blk, rd);
        diskread_callback = fileread_callback;
        for (i = ((off / SECSIZ) % pcfsp->f_bpb.bs_spc); i < spc; i++) {
            xfer = MIN(SECSIZ - (off % SECSIZ), c - count);
            if (xfer == 0)
                break;  /* last sector done */

            block = (char *)readblock(sector + i, 1);
            if (block == NULL) {
                return (-1);
            }
            dprintf("bpcfs_read: read %d bytes\n", xfer);
            if (diskread_callback == NULL)
                (void) bcopy(&block[off % SECSIZ], b, xfer);
            count += xfer;
            off += xfer;
            b += xfer;
        }

        diskread_callback = NULL;
        if (count < c) {
            blk = fat_map(blk, rd);
            if (!cluster_valid(blk, rd)) {
                printf("bpcfs_read: invalid cluster: %ld, %d\n",
                    blk, rd);
                break;
            }
        }
    }

    fp->fi_offset += count;
    return (count);
}

/*
 * This version of seek() only performs absolute seeks (whence == 0).
 */
static off_t
bpcfs_lseek(int fd, off_t addr, int whence)
{
    fileid_t *filep;

    dprintf("lseek %d, off = %lx\n", fd, addr);
    if (!(filep = find_fp(fd)))
        return (-1);

    switch (whence) {
    case SEEK_CUR:
        filep->fi_offset += addr;
        break;
    case SEEK_SET:
        filep->fi_offset = addr;
        break;
    default:
    case SEEK_END:
        printf("lseek(): invalid whence value %d\n", whence);
        break;
    }

    filep->fi_blocknum = addr / DEV_BSIZE;
    filep->fi_count = 0;
    return (0);
}

static fileid_t *
find_fp(int fd)
{
    fileid_t *filep = head;

    if (fd >= 0) {
        while ((filep = filep->fi_forw) != head)
            if (fd == filep->fi_filedes)
                return (filep->fi_taken ? filep : 0);
    }

    return (0);
}

static int
cluster_valid(long c, int rd)
{
    return ((rd && (c == 0)) ? 1 : (c >= CLUSTER_RES_16_0 ? 0 : c));
}

static int
fat_ctodb(int blk, int r)
{
    uint_t s;

    s = r ? blk + pcfsp->f_rootsec + pcfsp->f_adjust :
        ((blk - 2) * pcfsp->f_bpb.bs_spc) +
        pcfsp->f_filesec + pcfsp->f_adjust;

    return (s);
}

static int
fat_map(int blk, int rootdir)
{
    ulong_t sectn, fat_index;
    uchar_t *fp;

    if (rootdir) {
        return (blk > pcfsp->f_rootlen ? CLUSTER_EOF : blk + 1);
    }

    /* ---- Find out what sector this cluster is in ---- */
    fat_index = (pcfsp->f_16bit) ? ((ulong_t)blk << 1) :
        ((ulong_t)blk + ((uint_t)blk >> 1));

    sectn = (fat_index / SECSIZ) + ltohs(pcfsp->f_bpb.bs_resv_sectors)
        + pcfsp->f_adjust;

    /*
     * Read two sectors so that if our fat_index points at the last byte
     * byte we'll have the data needed.  This is only a problem for fat12
     * entries.
     */
    if (!(fp = (uchar_t *)readblock(sectn, 2))) {
        printf("fat_map: bad cluster\n");
        return (CLUSTER_BAD_16);
    }

    fp += (fat_index % SECSIZ);

    if (pcfsp->f_16bit)
        blk = fp[0] | (fp[1] << 8);
    else {
        if (blk & 1)
            blk = ((fp[0] >> 4) & 0xf) | (fp[1] << 4);
        else
            blk = ((fp[1] & 0xf) << 8) | fp[0];

        /*
         * This makes compares easier because we can just compare
         * against one value instead of two.
         */
        if (blk >= CLUSTER_RES_12_0)
            blk |= CLUSTER_RES_16_0;
    }
    return (blk);
}

static int
namecmp(char *pn, char *dn, int cs)
{
    dprintf("namecmp %s, %s, len = %d\n", pn, dn, cs);

    /* starting char must match */
    while (*pn && *dn) {
        --cs;
        if (toupper(*pn++) != toupper(*dn++))
            return (1);
    }

    dprintf("namecmp: cs = %d\n", cs);
    /* remainder should be either ~# or all spaces */
    if (cs > 0 && *dn == '~')
        return (0);
    while (cs > 0) {
        if (*dn++ != ' ')
            return (1);
        --cs;
    }
    return (0);
}

static int
dircmp(char *name, char *d_name, char *d_ext)
{
    int ret;
    char *sep, *ext;

    sep = (char *)strchr(name, '.');

    if (sep) {
        *sep = '\0';
        ext = sep + 1;
    } else
        ext = "   ";

    if (namecmp(name, d_name, NAMESIZ) || namecmp(ext, d_ext, EXTSIZ))
        ret = 1;
    else
        ret = 0;
    if (sep)
        *sep = '.';
    return (ret);
}

static int
lookup(char *n, _dir_entry_p dp, ulong_t dir_blk)
{
    int spc = pcfsp->f_bpb.bs_spc;
    int rd = (dir_blk == CLUSTER_ROOTDIR ? 1 : 0);
    _dir_entry_p dxp;
    int j, sector;

    dprintf("lookup: name = %s\n", n);

    while (cluster_valid(dir_blk, rd)) {
        sector = fat_ctodb(dir_blk, rd);
        dxp = readblock(sector, 1); /* read one sector */
        if (dxp == NULL)
            return (0);
        for (j = 0; j < DIRENTS * spc; j++, dxp++) {
            dprintf("lookup: dir entry %s.%s;\n",
                dxp->d_name, dxp->d_ext);
            if (dxp->d_name[0] == 0)
                return (0);
            if ((uchar_t)dxp->d_name[0] != 0xE5 &&
                (dxp->d_attr & (DE_LABEL|DE_HIDDEN)) == 0 &&
                dircmp(n, dxp->d_name, dxp->d_ext) == 0) {
                dprintf("lookup: match found\n");
                (void) bcopy(dxp, dp, sizeof (*dp));
                return (1);
            }
        }
        /* next cluster */
        dir_blk = fat_map(dir_blk, rd);
    }

    return (0);
}

static int
lookuppn(char *n, _dir_entry_p dp)
{
    long dir_blk;
    char name[8 + 1 + 3 + 1];   /* <8>.<3>'\0' */
    char *p, *ep;
    _dir_entry_t dd;

    dprintf("lookuppn: path = %s\n", n);
    dir_blk = pcfsp->f_dclust;
    if ((*n == '\\') || (*n == '/')) {
        dir_blk = CLUSTER_ROOTDIR;
        while ((*n == '\\') || (*n == '/'))
            n++;
        if (*n == '\0') {
            (void) bzero(dp, sizeof (*dp));
            dp->d_cluster = CLUSTER_ROOTDIR;
            dp->d_attr = DE_DIRECTORY;
            return (0);
        }
    }

    ep = &name[0] + sizeof (name);
    while (*n) {
        (void) bzero(name, sizeof (name));
        p = &name[0];
        while (*n && (*n != '\\') && (*n != '/'))
            if (p != ep)
                *p++ = *n++;
            else {
                dprintf("return, name %s is too long\n", name);
                return (-1);    /* name is too long */
            }
        while ((*n == '\\') || (*n == '/'))
            n++;
        if (lookup(name, &dd, dir_blk) == 0) {
            dprintf("return, name %s not found\n", name);
            return (-1);
        }
        dprintf("dd = %x:%x:%x attr = %x\n",
            *(int *)&dd, *(((int *)&dd) + 1),
            *(((int *)&dd) + 2), dd.d_attr);
        if (*n && ((dd.d_attr & DE_DIRECTORY) == 0)) {
            dprintf("return, not a directory\n");
            return (-1);
        }

        dir_blk = dd.d_cluster;
    }
    (void) bcopy(&dd, dp, sizeof (dd));
    return (0);
}

static void *
readblock(int sector, int nsec)
{
    if (sector >= nsec_start && sector + nsec <= nsec_start + nsec_cache)
        return (cluster_cache + (sector - nsec_start) * SECSIZ);

    /* read disk sectors */
    head->fi_blocknum = sector;
    head->fi_count = nsec * SECSIZ;
    head->fi_memp = head->fi_buf;
    if (diskread(head)) {
        printf("failed to %d sectors at %d\n", nsec, sector);
        return (NULL);
    }

    return (head->fi_buf);
}

struct boot_fs_ops bpcfs_ops = {
    "boot_pcfs",
    bpcfs_mountroot,
    bpcfs_unmountroot,
    bpcfs_open,
    bpcfs_close,
    bpcfs_read,
    bpcfs_lseek,
    NULL
};