Initial Spring 2016 commit.

userland/sbin/mksfs/disk.c

@@ -0,0 +1,200 @@
+/*
+ * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
+ *	The President and Fellows of Harvard College.
+ *
+ * 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.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``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 UNIVERSITY OR CONTRIBUTORS 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/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <assert.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <err.h>
+
+#include "support.h"
+#include "disk.h"
+
+#define HOSTSTRING "System/161 Disk Image"
+#define BLOCKSIZE  512
+
+#ifndef EINTR
+#define EINTR 0
+#endif
+
+static int fd=-1;
+static uint32_t nblocks;
+
+/*
+ * Open a disk. If we're built for the host OS, check that it's a
+ * System/161 disk image, and then ignore the header block.
+ */
+void
+opendisk(const char *path)
+{
+	struct stat statbuf;
+
+	assert(fd<0);
+	fd = open(path, O_RDWR);
+	if (fd<0) {
+		err(1, "%s", path);
+	}
+	if (fstat(fd, &statbuf)) {
+		err(1, "%s: fstat", path);
+	}
+
+	nblocks = statbuf.st_size / BLOCKSIZE;
+
+#ifdef HOST
+	nblocks--;
+
+	{
+		char buf[64];
+		int len;
+
+		do {
+			len = read(fd, buf, sizeof(buf)-1);
+			if (len < 0 && (errno==EINTR || errno==EAGAIN)) {
+				continue;
+			}
+		} while (0);
+
+		buf[len] = 0;
+		buf[strlen(HOSTSTRING)] = 0;
+
+		if (strcmp(buf, HOSTSTRING)) {
+			errx(1, "%s: Not a System/161 disk image", path);
+		}
+	}
+#endif
+}
+
+/*
+ * Return the block size. (This is fixed, but still...)
+ */
+uint32_t
+diskblocksize(void)
+{
+	assert(fd>=0);
+	return BLOCKSIZE;
+}
+
+/*
+ * Return the device/image size in blocks.
+ */
+uint32_t
+diskblocks(void)
+{
+	assert(fd>=0);
+	return nblocks;
+}
+
+/*
+ * Write a block.
+ */
+void
+diskwrite(const void *data, uint32_t block)
+{
+	const char *cdata = data;
+	uint32_t tot=0;
+	int len;
+
+	assert(fd>=0);
+
+#ifdef HOST
+	// skip over disk file header
+	block++;
+#endif
+
+	if (lseek(fd, block*BLOCKSIZE, SEEK_SET)<0) {
+		err(1, "lseek");
+	}
+
+	while (tot < BLOCKSIZE) {
+		len = write(fd, cdata + tot, BLOCKSIZE - tot);
+		if (len < 0) {
+			if (errno==EINTR || errno==EAGAIN) {
+				continue;
+			}
+			err(1, "write");
+		}
+		if (len==0) {
+			err(1, "write returned 0?");
+		}
+		tot += len;
+	}
+}
+
+/*
+ * Read a block.
+ */
+void
+diskread(void *data, uint32_t block)
+{
+	char *cdata = data;
+	uint32_t tot=0;
+	int len;
+
+	assert(fd>=0);
+
+#ifdef HOST
+	// skip over disk file header
+	block++;
+#endif
+
+	if (lseek(fd, block*BLOCKSIZE, SEEK_SET)<0) {
+		err(1, "lseek");
+	}
+
+	while (tot < BLOCKSIZE) {
+		len = read(fd, cdata + tot, BLOCKSIZE - tot);
+		if (len < 0) {
+			if (errno==EINTR || errno==EAGAIN) {
+				continue;
+			}
+			err(1, "read");
+		}
+		if (len==0) {
+			err(1, "unexpected EOF in mid-sector");
+		}
+		tot += len;
+	}
+}
+
+/*
+ * Close the disk.
+ */
+void
+closedisk(void)
+{
+	assert(fd>=0);
+	if (close(fd)) {
+		err(1, "close");
+	}
+	fd = -1;
+}