This is libstand; a support library for standalone executables (eg. bootstrap

modules).
Obtained from: NetBSD, with some architectural changes and many additions.

1 files changed, 660 insertions, 0 deletions

diff --git a/lib/libstand/dosfs.c b/lib/libstand/dosfs.c
new file mode 100644
index 0000000..90aa728
--- /dev/null
+++ b/lib/libstand/dosfs.c
@@ -0,0 +1,660 @@
+/*
+ * Copyright (c) 1996, 1998 Robert Nordier
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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(S) 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.
+ */
+
+/*
+ * Readonly filesystem for Microsoft FAT12/FAT16/FAT32 filesystems,
+ * also supports VFAT.
+ */
+
+#include <sys/types.h>
+#include <string.h>
+#include <stddef.h>
+
+#include "stand.h"
+
+#if 0
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#endif
+
+#include "dosfs.h"
+
+
+static int	dos_open(char *path, struct open_file *fd);
+static int	dos_close(struct open_file *fd);
+static int	dos_read(struct open_file *fd, void *buf, size_t size, size_t *resid);
+static off_t	dos_seek(struct open_file *fd, off_t offset, int whence);
+static int	dos_stat(struct open_file *fd, struct stat *sb);
+
+struct fs_ops dos_fsops = {
+    "dosfs", dos_open, dos_close, dos_read, null_write, dos_seek, dos_stat
+};
+
+#define SECSIZ  512             /* sector size */
+#define SSHIFT    9             /* SECSIZ shift */
+#define DEPSEC   16             /* directory entries per sector */
+#define DSHIFT    4             /* DEPSEC shift */
+#define LOCLUS    2             /* lowest cluster number */
+
+/* DOS "BIOS Parameter Block" */
+typedef struct {
+    u_char secsiz[2];           /* sector size */
+    u_char spc;                 /* sectors per cluster */
+    u_char ressec[2];           /* reserved sectors */
+    u_char fats;                /* FATs */
+    u_char dirents[2];          /* root directory entries */
+    u_char secs[2];             /* total sectors */
+    u_char media;               /* media descriptor */
+    u_char spf[2];              /* sectors per FAT */
+    u_char spt[2];              /* sectors per track */
+    u_char heads[2];            /* drive heads */
+    u_char hidsec[4];           /* hidden sectors */
+    u_char lsecs[4];            /* huge sectors */
+    u_char lspf[4];             /* huge sectors per FAT */
+    u_char xflg[2];             /* flags */
+    u_char vers[2];             /* filesystem version */
+    u_char rdcl[4];             /* root directory start cluster */
+    u_char infs[2];             /* filesystem info sector */
+    u_char bkbs[2];             /* backup boot sector */
+} DOS_BPB;
+
+/* Initial portion of DOS boot sector */
+typedef struct {
+    u_char jmp[3];              /* usually 80x86 'jmp' opcode */
+    u_char oem[8];              /* OEM name and version */
+    DOS_BPB bpb;                /* BPB */
+} DOS_BS;
+
+/* Supply missing "." and ".." root directory entries */
+static const char *const dotstr[2] = {".", ".."};
+static DOS_DE dot[2] = {
+    {".       ", "   ", FA_DIR, {0, 0, {0, 0}, {0, 0}, {0, 0}, {0, 0}},
+     {0, 0}, {0x21, 0}, {0, 0}, {0, 0, 0, 0}},
+    {"..      ", "   ", FA_DIR, {0, 0, {0, 0}, {0, 0}, {0, 0}, {0, 0}},
+     {0, 0}, {0x21, 0}, {0, 0}, {0, 0, 0, 0}}
+};
+
+/* The usual conversion macros to avoid multiplication and division */
+#define bytsec(n)      ((n) >> SSHIFT)
+#define secbyt(s)      ((s) << SSHIFT)
+#define entsec(e)      ((e) >> DSHIFT)
+#define bytblk(fs, n)  ((n) >> (fs)->bshift)
+#define blkbyt(fs, b)  ((b) << (fs)->bshift)
+#define secblk(fs, s)  ((s) >> ((fs)->bshift - SSHIFT))
+#define blksec(fs, b)  ((b) << ((fs)->bshift - SSHIFT))
+
+/* Convert cluster number to offset within filesystem */
+#define blkoff(fs, b) (secbyt((fs)->lsndta) + blkbyt(fs, (b) - LOCLUS))
+
+/* Convert cluster number to logical sector number */
+#define blklsn(fs, b)  ((fs)->lsndta + blksec(fs, (b) - LOCLUS))
+
+/* Convert cluster number to offset within FAT */
+#define fatoff(sz, c)  ((sz) == 12 ? (c) + ((c) >> 1) :  \
+                        (sz) == 16 ? (c) << 1 :          \
+			(c) << 2)
+
+/* Does cluster number reference a valid data cluster? */
+#define okclus(fs, c)  ((c) >= LOCLUS && (c) <= (fs)->xclus)
+
+/* Get start cluster from directory entry */
+#define stclus(sz, de)  ((sz) != 32 ? cv2((de)->clus) :          \
+                         ((u_int)cv2((de)->dex.h_clus) << 16) |  \
+			 cv2((de)->clus))
+    
+static int dosunmount(DOS_FS *);
+static int parsebs(DOS_FS *, DOS_BS *);
+static int namede(DOS_FS *, const char *, DOS_DE **);
+static int lookup(DOS_FS *, u_int, const char *, DOS_DE **);
+static void cp_xdnm(u_char *, DOS_XDE *);
+static void cp_sfn(u_char *, DOS_DE *);
+static int fatget(DOS_FS *, u_int *);
+static int fatend(u_int, u_int);
+static int ioread(DOS_FS *, u_int, void *, u_int);
+static int iobuf(DOS_FS *, u_int);
+static int ioget(struct open_file *, u_int, void *, u_int);
+
+/*
+ * Mount DOS filesystem
+ */
+static int
+dos_mount(DOS_FS *fs, struct open_file *fd)
+{
+    int err;
+
+    bzero(fs, sizeof(DOS_FS));
+    fs->fd = fd;
+    if ((err = !(fs->buf = alloc(SECSIZ)) ? errno : 0) ||
+        (err = ioget(fs->fd, 0, fs->buf, 1)) ||
+        (err = parsebs(fs, (DOS_BS *)fs->buf))) {
+        (void)dosunmount(fs);
+        return(err);
+    }
+    return 0;
+}
+
+/*
+ * Unmount mounted filesystem
+ */
+static int
+dos_unmount(DOS_FS *fs)
+{
+    int err;
+
+    if (fs->links)
+        return(EBUSY);
+    if ((err = dosunmount(fs)))
+        return(err);
+    return 0;
+}
+
+/*
+ * Common code shared by dos_mount() and dos_unmount()
+ */
+static int
+dosunmount(DOS_FS *fs)
+{
+    if (fs->buf)
+        free(fs->buf, 0);
+    free(fs, 0);
+    return(0);
+}
+
+/*
+ * Open DOS file
+ */
+static int
+dos_open(char *path, struct open_file *fd)
+{
+    DOS_DE *de;
+    DOS_FILE *f;
+    DOS_FS *fs;
+    u_int size, clus;
+    int err = 0;
+
+    /* Allocate mount structure, associate with open */
+    fs = alloc(sizeof(DOS_FS));
+    
+    if ((err = dos_mount(fs, fd)))
+	goto out;
+
+    if ((err = namede(fs, path, &de)))
+	goto out;
+
+    /* XXX we need to be able to open directories */
+    if (de->attr & FA_DIR) {
+        err = EISDIR;
+	goto out;
+    }
+    clus = stclus(fs->fatsz, de);
+    size = cv4(de->size);
+    if (!clus ^ !size || (clus && !okclus(fs, clus))) {
+        err = EINVAL;
+	goto out;
+    }
+    f = alloc(sizeof(DOS_FILE));
+    bzero(f, sizeof(DOS_FILE));
+    f->fs = fs;
+    fs->links++;
+    f->de = *de;
+    fd->f_fsdata = (void *)f;
+
+ out:
+    return(err);
+}
+
+/*
+ * Read from file
+ */
+static int
+dos_read(struct open_file *fd, void *buf, size_t nbyte, size_t *resid)
+{
+    u_int nb, off, clus, c, cnt, n;
+    DOS_FILE *f = (DOS_FILE *)fd->f_fsdata;
+    int err = 0;
+
+    nb = (u_int)nbyte;
+    if (nb > (n = cv4(f->de.size) - f->offset))
+        nb = n;
+    off = f->offset;
+    if ((clus = stclus(f->fs->fatsz, &f->de)))
+        off &= f->fs->bsize - 1;
+    c = f->c;
+    cnt = nb;
+    while (cnt) {
+        n = 0;
+        if (!c) {
+            if ((c = clus))
+                n = bytblk(f->fs, f->offset);
+        } else if (!off)
+            n++;
+        while (n--) {
+            if ((err = fatget(f->fs, &c)))
+		goto out;
+            if (!okclus(f->fs, c)) {
+		err = EINVAL;
+		goto out;
+	    }
+        }
+        if (!clus || (n = f->fs->bsize - off) > cnt)
+            n = cnt;
+        if ((err = ioread(f->fs, blkoff(f->fs, c) + off, buf, n)))
+	    goto out;
+        f->offset += n;
+        f->c = c;
+        off = 0;
+        buf += n;
+        cnt -= n;
+    }
+ out:
+    if (resid)
+	*resid = cnt;
+    return(err);
+}
+
+/*
+ * Reposition within file
+ */
+static off_t
+dos_seek(struct open_file *fd, off_t offset, int whence)
+{
+    off_t off;
+    u_int size;
+    DOS_FILE *f = (DOS_FILE *)fd->f_fsdata;
+
+    size = cv4(f->de.size);
+    switch (whence) {
+    case SEEK_SET:
+        off = 0;
+        break;
+    case SEEK_CUR:
+        off = f->offset;
+        break;
+    case SEEK_END:
+        off = size;
+        break;
+    default:
+	return(-1);
+    }
+    off += offset;
+    if (off < 0 || off > size)
+        return(-1);
+    f->offset = (u_int)off;
+    f->c = 0;
+    return(off);
+}
+
+/*
+ * Close open file
+ */
+static int
+dos_close(struct open_file *fd)
+{
+    DOS_FILE *f = (DOS_FILE *)fd->f_fsdata;
+    DOS_FS *fs = f->fs;
+
+    f->fs->links--;
+    free(f, 0);
+    dos_unmount(fs);
+    return 0;
+}
+
+/*
+ * Return some stat information on a file.
+ */
+static int
+dos_stat(struct open_file *fd, struct stat *sb)
+{
+    DOS_FILE *f = (DOS_FILE *)fd->f_fsdata;
+
+    /* only important stuff */
+    sb->st_mode = 0444;
+    sb->st_nlink = 1;
+    sb->st_uid = 0;
+    sb->st_gid = 0;
+    sb->st_size = cv4(f->de.size);
+    return (0);
+}
+
+/*
+ * Parse DOS boot sector
+ */
+static int
+parsebs(DOS_FS *fs, DOS_BS *bs)
+{
+    u_int sc;
+
+    if ((bs->jmp[0] != 0x69 &&
+         bs->jmp[0] != 0xe9 &&
+         (bs->jmp[0] != 0xeb || bs->jmp[2] != 0x90)) ||
+        bs->bpb.media < 0xf0)
+        return EINVAL;
+    if (cv2(bs->bpb.secsiz) != SECSIZ)
+        return EINVAL;
+    if (!(fs->spc = bs->bpb.spc) || fs->spc & (fs->spc - 1))
+        return EINVAL;
+    fs->bsize = secbyt(fs->spc);
+    fs->bshift = ffs(fs->bsize) - 1;
+    if ((fs->spf = cv2(bs->bpb.spf))) {
+        if (bs->bpb.fats != 2)
+            return EINVAL;
+        if (!(fs->dirents = cv2(bs->bpb.dirents)))
+            return EINVAL;
+    } else {
+        if (!(fs->spf = cv4(bs->bpb.lspf)))
+            return EINVAL;
+        if (!bs->bpb.fats || bs->bpb.fats > 16)
+            return EINVAL;
+        if ((fs->rdcl = cv4(bs->bpb.rdcl)) < LOCLUS)
+            return EINVAL;
+    }
+    if (!(fs->lsnfat = cv2(bs->bpb.ressec)))
+        return EINVAL;
+    fs->lsndir = fs->lsnfat + fs->spf * bs->bpb.fats;
+    fs->lsndta = fs->lsndir + entsec(fs->dirents);
+    if (!(sc = cv2(bs->bpb.secs)) && !(sc = cv4(bs->bpb.lsecs)))
+        return EINVAL;
+    if (fs->lsndta > sc)
+        return EINVAL;
+    if ((fs->xclus = secblk(fs, sc - fs->lsndta) + 1) < LOCLUS)
+        return EINVAL;
+    fs->fatsz = fs->dirents ? fs->xclus < 0xff6 ? 12 : 16 : 32;
+    sc = (secbyt(fs->spf) << 1) / (fs->fatsz >> 2) - 1;
+    if (fs->xclus > sc)
+        fs->xclus = sc;
+    return 0;
+}
+
+/*
+ * Return directory entry from path
+ */
+static int
+namede(DOS_FS *fs, const char *path, DOS_DE **dep)
+{
+    char name[256];
+    DOS_DE *de;
+    char *s;
+    size_t n;
+    int err;
+
+    err = 0;
+    de = dot;
+    if (*path == '/')
+        path++;
+    while (*path) {
+        if (!(s = strchr(path, '/')))
+            s = strchr(path, 0);
+        if ((n = s - path) > 255)
+            return ENAMETOOLONG;
+        memcpy(name, path, n);
+        name[n] = 0;
+        path = s;
+        if (!(de->attr & FA_DIR))
+            return ENOTDIR;
+        if ((err = lookup(fs, stclus(fs->fatsz, de), name, &de)))
+            return err;
+        if (*path == '/')
+            path++;
+    }
+    *dep = de;
+    return 0;
+}
+
+/*
+ * Lookup path segment
+ */
+static int
+lookup(DOS_FS *fs, u_int clus, const char *name, DOS_DE **dep)
+{
+    static DOS_DIR dir[DEPSEC];
+    u_char lfn[261];
+    u_char sfn[13];
+    u_int nsec, lsec, xdn, chk, sec, ent, x;
+    int err, ok, i;
+
+    if (!clus)
+        for (ent = 0; ent < 2; ent++)
+            if (!strcasecmp(name, dotstr[ent])) {
+                *dep = dot + ent;
+                return 0;
+            }
+    if (!clus && fs->fatsz == 32)
+        clus = fs->rdcl;
+    nsec = !clus ? entsec(fs->dirents) : fs->spc;
+    lsec = 0;
+    xdn = chk = 0;
+    for (;;) {
+        if (!clus && !lsec)
+            lsec = fs->lsndir;
+        else if (okclus(fs, clus))
+            lsec = blklsn(fs, clus);
+        else
+            return EINVAL;
+        for (sec = 0; sec < nsec; sec++) {
+            if ((err = ioget(fs->fd, lsec + sec, dir, 1)))
+                return err;
+            for (ent = 0; ent < DEPSEC; ent++) {
+                if (!*dir[ent].de.name)
+                    return ENOENT;
+                if (*dir[ent].de.name != 0xe5)
+                    if ((dir[ent].de.attr & FA_MASK) == FA_XDE) {
+                        x = dir[ent].xde.seq;
+                        if (x & 0x40 || (x + 1 == xdn &&
+                                         dir[ent].xde.chk == chk)) {
+                            if (x & 0x40) {
+                                chk = dir[ent].xde.chk;
+                                x &= ~0x40;
+                            }
+                            if (x >= 1 && x <= 20) {
+                                cp_xdnm(lfn, &dir[ent].xde);
+                                xdn = x;
+                                continue;
+                            }
+                        }
+                    } else if (!(dir[ent].de.attr & FA_LABEL)) {
+                        if ((ok = xdn == 1)) {
+                            for (x = 0, i = 0; i < 11; i++)
+                                x = ((((x & 1) << 7) | (x >> 1)) +
+                                     dir[ent].de.name[i]) & 0xff;
+                            ok = chk == x &&
+                                !strcasecmp(name, (const char *)lfn);
+                        }
+                        if (!ok) {
+                            cp_sfn(sfn, &dir[ent].de);
+                            ok = !strcasecmp(name, (const char *)sfn);
+                        }
+                        if (ok) {
+                            *dep = &dir[ent].de;
+                            return 0;
+                        }
+                    }
+                xdn = 0;
+            }
+        }
+        if (!clus)
+            break;
+        if ((err = fatget(fs, &clus)))
+            return err;
+        if (fatend(fs->fatsz, clus))
+            break;
+    }
+    return ENOENT;
+}
+
+/*
+ * Copy name from extended directory entry
+ */
+static void
+cp_xdnm(u_char *lfn, DOS_XDE *xde)
+{
+    static struct {
+        u_int off;
+        u_int dim;
+    } ix[3] = {
+        {offsetof(DOS_XDE, name1), sizeof(xde->name1) / 2},
+        {offsetof(DOS_XDE, name2), sizeof(xde->name2) / 2},
+        {offsetof(DOS_XDE, name3), sizeof(xde->name3) / 2}
+    };
+    u_char *p;
+    u_int n, x, c;
+
+    lfn += 13 * ((xde->seq & ~0x40) - 1);
+    for (n = 0; n < 3; n++)
+        for (p = (u_char *)xde + ix[n].off, x = ix[n].dim; x;
+	     p += 2, x--) {
+            if ((c = cv2(p)) && (c < 32 || c > 127))
+                c = '?';
+            if (!(*lfn++ = c))
+                return;
+        }
+    if (xde->seq & 0x40)
+        *lfn = 0;
+}
+
+/*
+ * Copy short filename
+ */
+static void
+cp_sfn(u_char *sfn, DOS_DE *de)
+{
+    u_char *p;
+    int j, i;
+
+    p = sfn;
+    if (*de->name != ' ') {
+        for (j = 7; de->name[j] == ' '; j--);
+        for (i = 0; i <= j; i++)
+            *p++ = de->name[i];
+        if (*de->ext != ' ') {
+            *p++ = '.';
+            for (j = 2; de->ext[j] == ' '; j--);
+            for (i = 0; i <= j; i++)
+                *p++ = de->ext[i];
+        }
+    }
+    *p = 0;
+    if (*sfn == 5)
+        *sfn = 0xe5;
+}
+
+/*
+ * Get next cluster in cluster chain
+ */
+static int
+fatget(DOS_FS *fs, u_int *c)
+{
+    u_char buf[4];
+    u_int x;
+    int err;
+
+    err = ioread(fs, secbyt(fs->lsnfat) + fatoff(fs->fatsz, *c), buf,
+                 fs->fatsz != 32 ? 2 : 4);
+    if (err)
+        return err;
+    x = fs->fatsz != 32 ? cv2(buf) : cv4(buf);
+    *c = fs->fatsz == 12 ? *c & 1 ? x >> 4 : x & 0xfff : x;
+    return 0;
+}
+
+/*
+ * Is cluster an end-of-chain marker?
+ */
+static int
+fatend(u_int sz, u_int c)
+{
+    return c > (sz == 12 ? 0xff7U : sz == 16 ? 0xfff7U : 0xffffff7);
+}
+
+/*
+ * Offset-based I/O primitive
+ */
+static int
+ioread(DOS_FS *fs, u_int offset, void *buf, u_int nbyte)
+{
+    char *s;
+    u_int off, n;
+    int err;
+
+    s = buf;
+    if ((off = offset & (SECSIZ - 1))) {
+        offset -= off;
+        if ((err = iobuf(fs, bytsec(offset))))
+            return err;
+        offset += SECSIZ;
+        if ((n = SECSIZ - off) > nbyte)
+            n = nbyte;
+        memcpy(s, fs->buf + off, n);
+        s += n;
+        nbyte -= n;
+    }
+    n = nbyte & (SECSIZ - 1);
+    if (nbyte -= n) {
+        if ((err = ioget(fs->fd, bytsec(offset), s, bytsec(nbyte))))
+            return err;
+        offset += nbyte;
+        s += nbyte;
+    }
+    if (n) {
+        if ((err = iobuf(fs, bytsec(offset))))
+            return err;
+        memcpy(s, fs->buf, n);
+    }
+    return 0;
+}
+
+/*
+ * Buffered sector-based I/O primitive
+ */
+static int
+iobuf(DOS_FS *fs, u_int lsec)
+{
+    int err;
+
+    if (fs->bufsec != lsec) {
+        if ((err = ioget(fs->fd, lsec, fs->buf, 1)))
+            return err;
+        fs->bufsec = lsec;
+    }
+    return 0;
+}
+
+/*
+ * Sector-based I/O primitive
+ */
+static int
+ioget(struct open_file *fd, u_int lsec, void *buf, u_int nsec)
+{
+    int	err;
+    
+    if ((err = (fd->f_dev->dv_strategy)(fd->f_devdata, F_READ, lsec, 
+					secbyt(nsec), buf, NULL)))
+	return(err);
+    return(0);
+}