1 files changed, 119 insertions, 0 deletions
diff --git a/text_cmds/tail/misc.c b/text_cmds/tail/misc.c
new file mode 100644
index 0000000..584e3d1
--- /dev/null
+++ b/text_cmds/tail/misc.c
@@ -0,0 +1,119 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Edward Sze-Tyan Wang.
+ *
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+
+__FBSDID("$FreeBSD$");
+
+#ifndef lint
+static const char sccsid[] = "@(#)misc.c	8.1 (Berkeley) 6/6/93";
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+#include <err.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "extern.h"
+
+void
+ierr()
+{
+	warn("%s", fname);
+	rval = 1;
+}
+
+void
+oerr()
+{
+	err(1, "stdout");
+}
+
+/*
+ * Print `len' bytes from the file associated with `mip', starting at
+ * absolute file offset `startoff'. May move map window.
+ */
+int
+mapprint(struct mapinfo *mip, off_t startoff, off_t len)
+{
+	int n;
+
+	while (len > 0) {
+		if (startoff < mip->mapoff || startoff >= mip->mapoff +
+		    (off_t)mip->maplen) {
+			if (maparound(mip, startoff) != 0)
+				return (1);
+		}
+		n = (mip->mapoff + mip->maplen) - startoff;
+		if (n > len)
+			n = len;
+		WR(mip->start + (startoff - mip->mapoff), n);
+		startoff += n;
+		len -= n;
+	}
+	return (0);
+}
+
+/*
+ * Move the map window so that it contains the byte at absolute file
+ * offset `offset'. The start of the map window will be TAILMAPLEN
+ * aligned.
+ */
+int
+maparound(struct mapinfo *mip, off_t offset)
+{
+
+	if (mip->start != NULL && munmap(mip->start, mip->maplen) != 0)
+		return (1);
+
+	mip->mapoff = offset & ~((off_t)TAILMAPLEN - 1);
+	mip->maplen = TAILMAPLEN;
+	if ((off_t)mip->maplen > mip->maxoff - mip->mapoff)
+		mip->maplen = mip->maxoff - mip->mapoff;
+	if (mip->maplen <= 0)
+		abort();
+	if ((mip->start = mmap(NULL, mip->maplen, PROT_READ, MAP_SHARED,
+	     mip->fd, mip->mapoff)) == MAP_FAILED)
+		return (1);
+
+	return (0);
+}