/usr.bin/tail/misc.c
https://bitbucket.org/freebsd/freebsd-head/ · C · 115 lines · 61 code · 14 blank · 40 comment · 14 complexity · bc249ac6ab19d81539003fddc9e52561 MD5 · raw file
- /*-
- * 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.
- * 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(const char *fname)
- {
- warn("%s", fname);
- rval = 1;
- }
- void
- oerr(void)
- {
- 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);
- }