Initial Spring 2016 commit.

userland/testbin/sparsefile/Makefile

@@ -0,0 +1,11 @@
+# Makefile for sparsefile
+
+TOP=../../..
+.include "$(TOP)/mk/os161.config.mk"
+
+PROG=sparsefile
+SRCS=sparsefile.c
+BINDIR=/testbin
+
+.include "$(TOP)/mk/os161.prog.mk"
+

userland/testbin/sparsefile/sparsefile.c

@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2014
+ *	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.
+ */
+
+/*
+ * Create a sparse file by writing one byte to the end of it.
+ *
+ * Should work on emufs (emu0:) once the basic system calls are done,
+ * and should work on SFS when the file system assignment is
+ * done. Sufficiently small files should work on SFS even before that
+ * assignment.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <err.h>
+
+int
+main(int argc, char *argv[])
+{
+	const char *filename;
+	int size;
+	int fd;
+	int r;
+	char byte;
+
+	if (argc != 3) {
+		errx(1, "Usage: sparsefile <filename> <size>");
+	}
+
+	filename = argv[1];
+	size = atoi(argv[2]);
+	byte = '\n';
+
+	if (size == 0) {
+		err(1, "Sparse files of length zero are not meaningful");
+	}
+
+	printf("Creating a sparse file of size %d\n", size);
+
+	fd = open(filename, O_WRONLY|O_CREAT|O_TRUNC);
+	if (fd < 0) {
+		err(1, "%s: create", filename);
+	}
+
+	if (lseek(fd, size-1, SEEK_SET) == -1) {
+		err(1, "%s: lseek", filename);
+	}
+	r = write(fd, &byte, 1);
+	if (r < 0) {
+		err(1, "%s: write", filename);
+	}
+	else if (r != 1) {
+		errx(1, "%s: write: Unexpected result count %d", filename, r);
+	}
+
+	close(fd);
+
+	return 0;
+}