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-rw-r--r--stand/libsa/dosfs.c868
1 files changed, 868 insertions, 0 deletions
diff --git a/stand/libsa/dosfs.c b/stand/libsa/dosfs.c
new file mode 100644
index 000000000000..68762842eaee
--- /dev/null
+++ b/stand/libsa/dosfs.c
@@ -0,0 +1,868 @@
+/*
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+/*
+ * Readonly filesystem for Microsoft FAT12/FAT16/FAT32 filesystems,
+ * also supports VFAT.
+ */
+
+#include <sys/types.h>
+#include <string.h>
+#include <stddef.h>
+
+#include "stand.h"
+
+#include "dosfs.h"
+
+
+static int dos_open(const 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);
+static int dos_readdir(struct open_file *fd, struct dirent *d);
+
+struct fs_ops dosfs_fsops = {
+ "dosfs",
+ dos_open,
+ dos_close,
+ dos_read,
+ null_write,
+ dos_seek,
+ dos_stat,
+ dos_readdir
+};
+
+#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 */
+#define FATBLKSZ 0x20000 /* size of block in the FAT cache buffer */
+
+/* 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 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 off_t fsize(DOS_FS *, DOS_DE *);
+static int fatcnt(DOS_FS *, u_int);
+static int fatget(DOS_FS *, u_int *);
+static int fatend(u_int, u_int);
+static int ioread(DOS_FS *, u_int, void *, size_t);
+static int ioget(struct open_file *, daddr_t, void *, size_t);
+
+static int
+dos_read_fatblk(DOS_FS *fs, struct open_file *fd, u_int blknum)
+{
+ int err;
+ size_t io_size;
+ daddr_t offset_in_fat, max_offset_in_fat;
+
+ offset_in_fat = ((daddr_t)blknum) * FATBLKSZ;
+ max_offset_in_fat = secbyt(fs->spf);
+ io_size = FATBLKSZ;
+ if (offset_in_fat > max_offset_in_fat)
+ offset_in_fat = max_offset_in_fat;
+ if (offset_in_fat + io_size > max_offset_in_fat)
+ io_size = ((size_t)(max_offset_in_fat - offset_in_fat));
+
+ if (io_size != 0) {
+ err = ioget(fd, fs->lsnfat + bytsec(offset_in_fat),
+ fs->fatbuf, io_size);
+ if (err != 0) {
+ fs->fatbuf_blknum = ((u_int)(-1));
+ return (err);
+ }
+ }
+ if (io_size < FATBLKSZ)
+ memset(fs->fatbuf + io_size, 0, FATBLKSZ - io_size);
+
+ fs->fatbuf_blknum = blknum;
+ return (0);
+}
+
+/*
+ * Mount DOS filesystem
+ */
+static int
+dos_mount(DOS_FS *fs, struct open_file *fd)
+{
+ int err;
+ u_char *buf;
+
+ bzero(fs, sizeof(DOS_FS));
+ fs->fd = fd;
+
+ if ((buf = malloc(secbyt(1))) == NULL)
+ return (errno);
+ if ((err = ioget(fs->fd, 0, buf, secbyt(1))) ||
+ (err = parsebs(fs, (DOS_BS *)buf))) {
+ free(buf);
+ return (err);
+ }
+ free(buf);
+
+ if ((fs->fatbuf = malloc(FATBLKSZ)) == NULL)
+ return (errno);
+ err = dos_read_fatblk(fs, fd, 0);
+ if (err != 0) {
+ free(fs->fatbuf);
+ return (err);
+ }
+
+ fs->root = dot[0];
+ fs->root.name[0] = ' ';
+ if (fs->fatsz == 32) {
+ fs->root.clus[0] = fs->rdcl & 0xff;
+ fs->root.clus[1] = (fs->rdcl >> 8) & 0xff;
+ fs->root.dex.h_clus[0] = (fs->rdcl >> 16) & 0xff;
+ fs->root.dex.h_clus[1] = (fs->rdcl >> 24) & 0xff;
+ }
+ return (0);
+}
+
+/*
+ * Unmount mounted filesystem
+ */
+static int
+dos_unmount(DOS_FS *fs)
+{
+ if (fs->links)
+ return (EBUSY);
+ free(fs->fatbuf);
+ free(fs);
+ return (0);
+}
+
+/*
+ * Open DOS file
+ */
+static int
+dos_open(const char *path, struct open_file *fd)
+{
+ DOS_DE *de;
+ DOS_FILE *f;
+ DOS_FS *fs;
+ u_int size, clus;
+ int err;
+
+ /* Allocate mount structure, associate with open */
+ if ((fs = malloc(sizeof(DOS_FS))) == NULL)
+ return (errno);
+ if ((err = dos_mount(fs, fd))) {
+ free(fs);
+ return (err);
+ }
+
+ if ((err = namede(fs, path, &de))) {
+ dos_unmount(fs);
+ return (err);
+ }
+
+ clus = stclus(fs->fatsz, de);
+ size = cv4(de->size);
+
+ if ((!(de->attr & FA_DIR) && (!clus != !size)) ||
+ ((de->attr & FA_DIR) && size) ||
+ (clus && !okclus(fs, clus))) {
+ dos_unmount(fs);
+ return (EINVAL);
+ }
+ if ((f = malloc(sizeof(DOS_FILE))) == NULL) {
+ err = errno;
+ dos_unmount(fs);
+ return (err);
+ }
+ bzero(f, sizeof(DOS_FILE));
+ f->fs = fs;
+ fs->links++;
+ f->de = *de;
+ fd->f_fsdata = (void *)f;
+ return (0);
+}
+
+/*
+ * Read from file
+ */
+static int
+dos_read(struct open_file *fd, void *buf, size_t nbyte, size_t *resid)
+{
+ off_t size;
+ u_int nb, off, clus, c, cnt, n;
+ DOS_FILE *f = (DOS_FILE *)fd->f_fsdata;
+ int err = 0;
+
+ /*
+ * as ioget() can be called *a lot*, use twiddle here.
+ * also 4 seems to be good value not to slow loading down too much:
+ * with 270MB file (~540k ioget() calls, twiddle can easily waste 4-5sec.
+ */
+ twiddle(4);
+ nb = (u_int)nbyte;
+ if ((size = fsize(f->fs, &f->de)) == -1)
+ return (EINVAL);
+ if (nb > (n = 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, (c ? blkoff(f->fs, c) :
+ secbyt(f->fs->lsndir)) + off, buf, n)))
+ goto out;
+ f->offset += n;
+ f->c = c;
+ off = 0;
+ buf = (char *)buf + n;
+ cnt -= n;
+ }
+ out:
+ if (resid)
+ *resid = nbyte - nb + 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:
+ errno = EINVAL;
+ return (-1);
+ }
+ off += offset;
+ if (off < 0 || off > size) {
+ errno = EINVAL;
+ 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);
+ 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 = f->de.attr & FA_DIR ? S_IFDIR | 0555 : S_IFREG | 0444;
+ sb->st_nlink = 1;
+ sb->st_uid = 0;
+ sb->st_gid = 0;
+ if ((sb->st_size = fsize(f->fs, &f->de)) == -1)
+ return (EINVAL);
+ return (0);
+}
+
+static int
+dos_checksum(char *name, char *ext)
+{
+ int x, i;
+ char buf[11];
+
+ bcopy(name, buf, 8);
+ bcopy(ext, buf+8, 3);
+ x = 0;
+ for (i = 0; i < 11; i++) {
+ x = ((x & 1) << 7) | (x >> 1);
+ x += buf[i];
+ x &= 0xff;
+ }
+ return (x);
+}
+
+static int
+dos_readdir(struct open_file *fd, struct dirent *d)
+{
+ /* DOS_FILE *f = (DOS_FILE *)fd->f_fsdata; */
+ u_char fn[261];
+ DOS_DIR dd;
+ size_t res;
+ u_int chk, x, xdn;
+ int err;
+
+ x = chk = 0;
+ while (1) {
+ xdn = x;
+ x = 0;
+ err = dos_read(fd, &dd, sizeof(dd), &res);
+ if (err)
+ return (err);
+ if (res == sizeof(dd))
+ return (ENOENT);
+ if (dd.de.name[0] == 0)
+ return (ENOENT);
+
+ /* Skip deleted entries */
+ if (dd.de.name[0] == 0xe5)
+ continue;
+
+ /* Check if directory entry is volume label */
+ if (dd.de.attr & FA_LABEL) {
+ /*
+ * If volume label set, check if the current entry is
+ * extended entry (FA_XDE) for long file names.
+ */
+ if ((dd.de.attr & FA_MASK) == FA_XDE) {
+ /*
+ * Read through all following extended entries
+ * to get the long file name. 0x40 marks the
+ * last entry containing part of long file name.
+ */
+ if (dd.xde.seq & 0x40)
+ chk = dd.xde.chk;
+ else if (dd.xde.seq != xdn - 1 || dd.xde.chk != chk)
+ continue;
+ x = dd.xde.seq & ~0x40;
+ if (x < 1 || x > 20) {
+ x = 0;
+ continue;
+ }
+ cp_xdnm(fn, &dd.xde);
+ } else {
+ /* skip only volume label entries */
+ continue;
+ }
+ } else {
+ if (xdn == 1) {
+ x = dos_checksum(dd.de.name, dd.de.ext);
+ if (x == chk)
+ break;
+ } else {
+ cp_sfn(fn, &dd.de);
+ break;
+ }
+ x = 0;
+ }
+ }
+
+ d->d_fileno = (dd.de.clus[1] << 8) + dd.de.clus[0];
+ d->d_reclen = sizeof(*d);
+ d->d_type = (dd.de.attr & FA_DIR) ? DT_DIR : DT_REG;
+ memcpy(d->d_name, fn, sizeof(d->d_name));
+ 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 = &fs->root;
+ while (*path) {
+ while (*path == '/')
+ path++;
+ if (*path == '\0')
+ break;
+ 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);
+ }
+ *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;
+
+ 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, secbyt(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)) {
+ x = dos_checksum(dir[ent].de.name, dir[ent].de.ext);
+ 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;
+}
+
+/*
+ * Return size of file in bytes
+ */
+static off_t
+fsize(DOS_FS *fs, DOS_DE *de)
+{
+ u_long size;
+ u_int c;
+ int n;
+
+ if (!(size = cv4(de->size)) && de->attr & FA_DIR) {
+ if (!(c = cv2(de->clus)))
+ size = fs->dirents * sizeof(DOS_DE);
+ else {
+ if ((n = fatcnt(fs, c)) == -1)
+ return (n);
+ size = blkbyt(fs, n);
+ }
+ }
+ return (size);
+}
+
+/*
+ * Count number of clusters in chain
+ */
+static int
+fatcnt(DOS_FS *fs, u_int c)
+{
+ int n;
+
+ for (n = 0; okclus(fs, c); n++)
+ if (fatget(fs, &c))
+ return (-1);
+ return (fatend(fs->fatsz, c) ? n : -1);
+}
+
+/*
+ * Get next cluster in cluster chain. Use in core fat cache unless
+ * the number of current 128K block in FAT has changed.
+ */
+static int
+fatget(DOS_FS *fs, u_int *c)
+{
+ u_int val_in, val_out, offset, blknum, nbyte;
+ const u_char *p_entry;
+ int err;
+
+ /* check input value to prevent overflow in fatoff() */
+ val_in = *c;
+ if (val_in & 0xf0000000)
+ return (EINVAL);
+
+ /* ensure that current 128K FAT block is cached */
+ offset = fatoff(fs->fatsz, val_in);
+ nbyte = fs->fatsz != 32 ? 2 : 4;
+ if (offset + nbyte > secbyt(fs->spf))
+ return (EINVAL);
+ blknum = offset / FATBLKSZ;
+ offset %= FATBLKSZ;
+ if (offset + nbyte > FATBLKSZ)
+ return (EINVAL);
+ if (blknum != fs->fatbuf_blknum) {
+ err = dos_read_fatblk(fs, fs->fd, blknum);
+ if (err != 0)
+ return (err);
+ }
+ p_entry = fs->fatbuf + offset;
+
+ /* extract cluster number from FAT entry */
+ switch (fs->fatsz) {
+ case 32:
+ val_out = cv4(p_entry);
+ val_out &= 0x0fffffff;
+ break;
+ case 16:
+ val_out = cv2(p_entry);
+ break;
+ case 12:
+ val_out = cv2(p_entry);
+ if (val_in & 1)
+ val_out >>= 4;
+ else
+ val_out &= 0xfff;
+ break;
+ default:
+ return (EINVAL);
+ }
+ *c = val_out;
+ 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, size_t nbyte)
+{
+ char *s;
+ u_int off, n;
+ int err;
+ u_char local_buf[SECSIZ];
+
+ s = buf;
+ if ((off = offset & (SECSIZ - 1))) {
+ offset -= off;
+ if ((n = SECSIZ - off) > nbyte)
+ n = nbyte;
+ if ((err = ioget(fs->fd, bytsec(offset), local_buf, sizeof(local_buf))))
+ return (err);
+ memcpy(s, local_buf + off, n);
+ offset += SECSIZ;
+ s += n;
+ nbyte -= n;
+ }
+ n = nbyte & (SECSIZ - 1);
+ if (nbyte -= n) {
+ if ((err = ioget(fs->fd, bytsec(offset), s, nbyte)))
+ return (err);
+ offset += nbyte;
+ s += nbyte;
+ }
+ if (n) {
+ if ((err = ioget(fs->fd, bytsec(offset), local_buf, sizeof(local_buf))))
+ return (err);
+ memcpy(s, local_buf, n);
+ }
+ return (0);
+}
+
+/*
+ * Sector-based I/O primitive
+ */
+static int
+ioget(struct open_file *fd, daddr_t lsec, void *buf, size_t size)
+{
+ size_t rsize;
+ int rv;
+
+ /* Make sure we get full read or error. */
+ rsize = 0;
+ rv = (fd->f_dev->dv_strategy)(fd->f_devdata, F_READ, lsec,
+ size, buf, &rsize);
+ if ((rv == 0) && (size != rsize))
+ rv = EIO;
+ return (rv);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 12:45:50 +0000