22da50cfc8
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
215 lines
5.5 KiB
C
215 lines
5.5 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[] = "@(#)read.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 <err.h>
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#include <errno.h>
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#include <fcntl.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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/*
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* bytes -- read bytes to an offset from the end and display.
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*
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* This is the function that reads to a byte offset from the end of the input,
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* storing the data in a wrap-around buffer which is then displayed. If the
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* rflag is set, the data is displayed in lines in reverse order, and this
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* routine has the usual nastiness of trying to find the newlines. Otherwise,
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* it is displayed from the character closest to the beginning of the input to
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* the end.
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*/
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int
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bytes(FILE *fp, const char *fn, off_t off)
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{
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int ch, len, tlen;
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char *ep, *p, *t;
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int wrap;
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char *sp;
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if ((sp = p = malloc(off)) == NULL)
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err(1, "malloc");
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for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) {
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*p = ch;
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if (++p == ep) {
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wrap = 1;
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p = sp;
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}
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}
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if (ferror(fp)) {
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ierr(fn);
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free(sp);
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return 1;
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}
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if (rflag) {
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for (t = p - 1, len = 0; t >= sp; --t, ++len)
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if (*t == '\n' && len) {
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WR(t + 1, len);
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len = 0;
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}
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if (wrap) {
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tlen = len;
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for (t = ep - 1, len = 0; t >= p; --t, ++len)
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if (*t == '\n') {
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if (len) {
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WR(t + 1, len);
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len = 0;
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}
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if (tlen) {
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WR(sp, tlen);
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tlen = 0;
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}
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}
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if (len)
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WR(t + 1, len);
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if (tlen)
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WR(sp, tlen);
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}
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} else {
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if (wrap && (len = ep - p))
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WR(p, len);
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len = p - sp;
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if (len)
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WR(sp, len);
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}
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free(sp);
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return 0;
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}
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/*
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* lines -- read lines to an offset from the end and display.
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*
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* This is the function that reads to a line offset from the end of the input,
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* storing the data in an array of buffers which is then displayed. If the
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* rflag is set, the data is displayed in lines in reverse order, and this
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* routine has the usual nastiness of trying to find the newlines. Otherwise,
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* it is displayed from the line closest to the beginning of the input to
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* the end.
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*/
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int
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lines(FILE *fp, const char *fn, off_t off)
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{
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struct {
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int blen;
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u_int len;
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char *l;
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} *llines;
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int ch, rc;
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char *p, *sp;
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int blen, cnt, recno, wrap;
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if ((llines = malloc(off * sizeof(*llines))) == NULL)
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err(1, "malloc");
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bzero(llines, off * sizeof(*llines));
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p = sp = NULL;
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blen = cnt = recno = wrap = 0;
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rc = 0;
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while ((ch = getc(fp)) != EOF) {
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if (++cnt > blen) {
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if ((sp = realloc(sp, blen += 1024)) == NULL)
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err(1, "realloc");
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p = sp + cnt - 1;
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}
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*p++ = ch;
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if (ch == '\n') {
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if ((int)llines[recno].blen < cnt) {
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llines[recno].blen = cnt + 256;
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if ((llines[recno].l = realloc(llines[recno].l,
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llines[recno].blen)) == NULL)
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err(1, "realloc");
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}
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bcopy(sp, llines[recno].l, llines[recno].len = cnt);
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cnt = 0;
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p = sp;
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if (++recno == off) {
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wrap = 1;
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recno = 0;
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}
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}
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}
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if (ferror(fp)) {
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ierr(fn);
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rc = 1;
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goto done;
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}
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if (cnt) {
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llines[recno].l = sp;
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sp = NULL;
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llines[recno].len = cnt;
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if (++recno == off) {
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wrap = 1;
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recno = 0;
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}
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}
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if (rflag) {
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for (cnt = recno - 1; cnt >= 0; --cnt)
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WR(llines[cnt].l, llines[cnt].len);
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if (wrap)
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for (cnt = off - 1; cnt >= recno; --cnt)
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WR(llines[cnt].l, llines[cnt].len);
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} else {
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if (wrap)
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for (cnt = recno; cnt < off; ++cnt)
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WR(llines[cnt].l, llines[cnt].len);
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for (cnt = 0; cnt < recno; ++cnt)
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WR(llines[cnt].l, llines[cnt].len);
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}
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done:
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for (cnt = 0; cnt < off; cnt++)
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free(llines[cnt].l);
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free(sp);
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free(llines);
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return (rc);
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}
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