Initial Spring 2016 commit.

userland/testbin/tail/Makefile

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

userland/testbin/tail/tail.c

@@ -0,0 +1,81 @@
+/*
+ * 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.
+ */
+
+/*
+ * tail.c
+ *
+ * 	Outputs a file beginning at a specific location.
+ *	Usage: tail <file> <location>
+ *
+ * This may be useful for testing during the file system assignment.
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <err.h>
+
+#define BUFSIZE 1000
+
+/* Put buffer in data space.  We know that the program should allocate as */
+/* much data space as required, but stack space is tight. */
+
+char buffer[BUFSIZE];
+
+static
+void
+tail(int file, off_t where, const char *filename)
+{
+	int len;
+
+	if (lseek(file, where, SEEK_SET)<0) {
+		err(1, "%s", filename);
+	}
+
+	while ((len = read(file, buffer, sizeof(buffer))) > 0) {
+		write(STDOUT_FILENO, buffer, len);
+	}
+}
+
+int
+main(int argc, char **argv)
+{
+	int file;
+
+	if (argc < 3) {
+		errx(1, "Usage: tail <file> <location>");
+	}
+	file = open(argv[1], O_RDONLY);
+	if (file < 0) {
+		err(1, "%s", argv[1]);
+	}
+	tail(file, atoi(argv[2]), argv[1]);
+	close(file);
+	return 0;
+}
+