Index: head/bin/echo/echo.c
===================================================================
--- head/bin/echo/echo.c	(revision 121009)
+++ head/bin/echo/echo.c	(revision 121010)
@@ -1,92 +1,141 @@
 /*
  * Copyright (c) 1989, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
  * 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. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgement:
  *	This product includes software developed by the University of
  *	California, Berkeley and its contributors.
  * 4. 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 REGENTS 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 REGENTS 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.
  */
 
 #if 0
 #ifndef lint
 static char const copyright[] =
 "@(#) Copyright (c) 1989, 1993\n\
 	The Regents of the University of California.  All rights reserved.\n";
 #endif /* not lint */
 
 #ifndef lint
 static char sccsid[] = "@(#)echo.c	8.1 (Berkeley) 5/31/93";
 #endif /* not lint */
 #endif
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <unistd.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
-/* ARGSUSED */
+/*
+ * Report an error and exit.
+ * Use it instead of err(3) to avoid linking-in stdio.
+ */
+static void
+errexit(const char *prog, const char *reason)
+{
+	char *errstr = strerror(errno);
+	write(STDERR_FILENO, prog, strlen(prog));
+	write(STDERR_FILENO, ": ", 2);
+	write(STDERR_FILENO, reason, strlen(reason));
+	write(STDERR_FILENO, ": ", 2);
+	write(STDERR_FILENO, errstr, strlen(errstr));
+	write(STDERR_FILENO, "\n", 1);
+	exit(1);
+}
+	
 int
-main(int argc __unused, char *argv[])
+main(int argc, char *argv[])
 {
 	int nflag;	/* if not set, output a trailing newline. */
+	int veclen;	/* number of writev arguments. */
+	struct iovec *iov, *vp; /* Elements to write, current element. */
+	char space[] = " ";
+	char newline[] = "\n";
+	char *progname = argv[0];
 
 	/* This utility may NOT do getopt(3) option parsing. */
 	if (*++argv && !strcmp(*argv, "-n")) {
 		++argv;
+		--argc;
 		nflag = 1;
-	}
-	else
+	} else
 		nflag = 0;
 
+	veclen = (argc >= 2) ? (argc - 2) * 2 + 1 : 0;
+
+	if ((vp = iov = malloc((veclen + 1) * sizeof(struct iovec))) == NULL)
+		errexit(progname, "malloc");
+
 	while (argv[0] != NULL) {
 		size_t len;
 		
 		len = strlen(argv[0]);
 
 		/*
 		 * If the next argument is NULL then this is this
 		 * the last argument, therefore we need to check
 		 * for a trailing \c.
 		 */
 		if (argv[1] == NULL) {
 			/* is there room for a '\c' and is there one? */
 			if (len >= 2 &&
 			    argv[0][len - 2] == '\\' &&
 			    argv[0][len - 1] == 'c') {
 				/* chop it and set the no-newline flag. */
 				len -= 2;
 				nflag = 1;
 			}
 		}
-		write(STDOUT_FILENO, argv[0], len);
-		if (*++argv)
-			write(STDOUT_FILENO, " ", 1);
+		vp->iov_base = *argv;
+		vp++->iov_len = len;
+		if (*++argv) {
+			vp->iov_base = space;
+			vp++->iov_len = 1;
+		}
 	}
-	if (!nflag)
-		write(STDOUT_FILENO, "\n", 1);
+	if (!nflag) {
+		veclen++;
+		vp->iov_base = newline;
+		vp++->iov_len = 1;
+	}
+	/* assert(veclen == (vp - iov)); */
+	while (veclen) {
+		int nwrite;
+
+		nwrite = (veclen > IOV_MAX) ? IOV_MAX : veclen;
+		if (writev(STDOUT_FILENO, iov, nwrite) == -1)
+			errexit(progname, "write");
+		iov += nwrite;
+		veclen -= nwrite;
+	}
 	return 0;
 }