330bc8582d
trying to open files rather than giving up when it encounters an error. ENOENT errors are not reported. As a result, files that are moved away then recreated are not at risk of being 'lost' to tail. Files that are recreated and temporarily have unreadable permissions will be shown when they are fixed. This behaviour is consistent with the GNU version of tail but without the verbiage that goes with the GNU version. This change also fixes error messages accompanying -f and -F. They no longer report problems with (null)! MFC after: 3 weeks
120 lines
3.5 KiB
C
120 lines
3.5 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Edward Sze-Tyan Wang.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#ifndef lint
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static const char sccsid[] = "@(#)misc.c 8.1 (Berkeley) 6/6/93";
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#endif
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <err.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "extern.h"
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void
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ierr(const char *fname)
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{
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warn("%s", fname);
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rval = 1;
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}
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void
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oerr()
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{
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err(1, "stdout");
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}
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/*
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* Print `len' bytes from the file associated with `mip', starting at
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* absolute file offset `startoff'. May move map window.
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*/
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int
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mapprint(struct mapinfo *mip, off_t startoff, off_t len)
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{
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int n;
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while (len > 0) {
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if (startoff < mip->mapoff || startoff >= mip->mapoff +
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(off_t)mip->maplen) {
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if (maparound(mip, startoff) != 0)
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return (1);
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}
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n = (mip->mapoff + mip->maplen) - startoff;
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if (n > len)
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n = len;
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WR(mip->start + (startoff - mip->mapoff), n);
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startoff += n;
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len -= n;
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}
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return (0);
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}
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/*
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* Move the map window so that it contains the byte at absolute file
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* offset `offset'. The start of the map window will be TAILMAPLEN
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* aligned.
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*/
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int
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maparound(struct mapinfo *mip, off_t offset)
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{
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if (mip->start != NULL && munmap(mip->start, mip->maplen) != 0)
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return (1);
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mip->mapoff = offset & ~((off_t)TAILMAPLEN - 1);
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mip->maplen = TAILMAPLEN;
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if ((off_t)mip->maplen > mip->maxoff - mip->mapoff)
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mip->maplen = mip->maxoff - mip->mapoff;
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if (mip->maplen <= 0)
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abort();
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if ((mip->start = mmap(NULL, mip->maplen, PROT_READ, MAP_SHARED,
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mip->fd, mip->mapoff)) == MAP_FAILED)
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return (1);
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return (0);
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}
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