Initial Spring 2016 commit.

userland/bin/cat/Makefile

@@ -0,0 +1,12 @@
+# Makefile for cat
+
+TOP=../../..
+.include "$(TOP)/mk/os161.config.mk"
+
+PROG=cat
+SRCS=cat.c
+BINDIR=/bin
+
+
+.include "$(TOP)/mk/os161.prog.mk"
+

userland/bin/cat/cat.c

@@ -0,0 +1,120 @@
+/*
+ * 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 <unistd.h>
+#include <string.h>
+#include <err.h>
+
+/*
+ * cat - concatenate and print
+ * Usage: cat [files]
+ */
+
+
+
+/* Print a file that's already been opened. */
+static
+void
+docat(const char *name, int fd)
+{
+	char buf[1024];
+	int len, wr, wrtot;
+
+	/*
+	 * As long as we get more than zero bytes, we haven't hit EOF.
+	 * Zero means EOF. Less than zero means an error occurred.
+	 * We may read less than we asked for, though, in various cases
+	 * for various reasons.
+	 */
+	while ((len = read(fd, buf, sizeof(buf)))>0) {
+		/*
+		 * Likewise, we may actually write less than we attempted
+		 * to. So loop until we're done.
+		 */
+		wrtot = 0;
+		while (wrtot < len) {
+			wr = write(STDOUT_FILENO, buf+wrtot, len-wrtot);
+			if (wr<0) {
+				err(1, "stdout");
+			}
+			wrtot += wr;
+		}
+	}
+	/*
+	 * If we got a read error, print it and exit.
+	 */
+	if (len<0) {
+		err(1, "%s", name);
+	}
+}
+
+/* Print a file by name. */
+static
+void
+cat(const char *file)
+{
+	int fd;
+
+	/*
+	 * "-" means print stdin.
+	 */
+	if (!strcmp(file, "-")) {
+		docat("stdin", STDIN_FILENO);
+		return;
+	}
+
+	/*
+	 * Open the file, print it, and close it.
+	 * Bail out if we can't open it.
+	 */
+	fd = open(file, O_RDONLY);
+	if (fd<0) {
+		err(1, "%s", file);
+	}
+	docat(file, fd);
+	close(fd);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+	if (argc==1) {
+		/* No args - just do stdin */
+		docat("stdin", STDIN_FILENO);
+	}
+	else {
+		/* Print all the files specified on the command line. */
+		int i;
+		for (i=1; i<argc; i++) {
+			cat(argv[i]);
+		}
+	}
+	return 0;
+}