201 lines
4.0 KiB
C
201 lines
4.0 KiB
C
/*
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* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
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* The President and Fellows of Harvard College.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <assert.h>
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#include <stdint.h>
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#include <string.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <err.h>
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#include "support.h"
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#include "disk.h"
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#define HOSTSTRING "System/161 Disk Image"
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#define BLOCKSIZE 512
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#ifndef EINTR
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#define EINTR 0
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#endif
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static int fd=-1;
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static uint32_t nblocks;
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/*
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* Open a disk. If we're built for the host OS, check that it's a
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* System/161 disk image, and then ignore the header block.
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*/
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void
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opendisk(const char *path)
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{
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struct stat statbuf;
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assert(fd<0);
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fd = open(path, O_RDWR);
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if (fd<0) {
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err(1, "%s", path);
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}
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if (fstat(fd, &statbuf)) {
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err(1, "%s: fstat", path);
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}
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nblocks = statbuf.st_size / BLOCKSIZE;
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#ifdef HOST
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nblocks--;
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{
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char buf[64];
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int len;
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do {
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len = read(fd, buf, sizeof(buf)-1);
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if (len < 0 && (errno==EINTR || errno==EAGAIN)) {
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continue;
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}
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} while (0);
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buf[len] = 0;
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buf[strlen(HOSTSTRING)] = 0;
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if (strcmp(buf, HOSTSTRING)) {
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errx(1, "%s: Not a System/161 disk image", path);
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}
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}
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#endif
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}
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/*
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* Return the block size. (This is fixed, but still...)
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*/
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uint32_t
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diskblocksize(void)
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{
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assert(fd>=0);
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return BLOCKSIZE;
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}
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/*
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* Return the device/image size in blocks.
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*/
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uint32_t
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diskblocks(void)
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{
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assert(fd>=0);
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return nblocks;
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}
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/*
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* Write a block.
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*/
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void
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diskwrite(const void *data, uint32_t block)
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{
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const char *cdata = data;
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uint32_t tot=0;
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int len;
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assert(fd>=0);
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#ifdef HOST
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// skip over disk file header
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block++;
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#endif
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if (lseek(fd, block*BLOCKSIZE, SEEK_SET)<0) {
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err(1, "lseek");
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}
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while (tot < BLOCKSIZE) {
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len = write(fd, cdata + tot, BLOCKSIZE - tot);
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if (len < 0) {
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if (errno==EINTR || errno==EAGAIN) {
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continue;
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}
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err(1, "write");
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}
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if (len==0) {
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err(1, "write returned 0?");
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}
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tot += len;
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}
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}
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/*
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* Read a block.
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*/
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void
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diskread(void *data, uint32_t block)
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{
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char *cdata = data;
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uint32_t tot=0;
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int len;
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assert(fd>=0);
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#ifdef HOST
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// skip over disk file header
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block++;
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#endif
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if (lseek(fd, block*BLOCKSIZE, SEEK_SET)<0) {
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err(1, "lseek");
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}
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while (tot < BLOCKSIZE) {
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len = read(fd, cdata + tot, BLOCKSIZE - tot);
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if (len < 0) {
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if (errno==EINTR || errno==EAGAIN) {
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continue;
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}
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err(1, "read");
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}
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if (len==0) {
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err(1, "unexpected EOF in mid-sector");
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}
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tot += len;
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}
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}
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/*
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* Close the disk.
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*/
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void
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closedisk(void)
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{
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assert(fd>=0);
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if (close(fd)) {
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err(1, "close");
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}
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fd = -1;
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}
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