This change only affects strings passed to -c, when the -s option is not used. The approach is to check if there may be additional data in the string after parsing each command. If there is none, use the EV_EXIT flag so that a fork may be omitted in specific cases. If there are empty lines after the command, the check will not see the end and forks will not be omitted. The same thing seems to happen in bash. Example: sh -c 'ps lT' No longer shows a shell process waiting for ps to finish. PR: bin/113860 Reviewed by: stefanf Approved by: ed (mentor)
538 lines
11 KiB
C
538 lines
11 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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* Kenneth Almquist.
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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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* 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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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)input.c 8.3 (Berkeley) 6/9/95";
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#endif
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#endif /* not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <stdio.h> /* defines BUFSIZ */
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#include <fcntl.h>
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#include <errno.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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/*
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* This file implements the input routines used by the parser.
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*/
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#include "shell.h"
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#include "redir.h"
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#include "syntax.h"
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#include "input.h"
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#include "output.h"
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#include "options.h"
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#include "memalloc.h"
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#include "error.h"
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#include "alias.h"
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#include "parser.h"
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#include "myhistedit.h"
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#include "trap.h"
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#define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */
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MKINIT
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struct strpush {
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struct strpush *prev; /* preceding string on stack */
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char *prevstring;
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int prevnleft;
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int prevlleft;
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struct alias *ap; /* if push was associated with an alias */
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};
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/*
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* The parsefile structure pointed to by the global variable parsefile
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* contains information about the current file being read.
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*/
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MKINIT
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struct parsefile {
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struct parsefile *prev; /* preceding file on stack */
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int linno; /* current line */
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int fd; /* file descriptor (or -1 if string) */
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int nleft; /* number of chars left in this line */
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int lleft; /* number of lines left in this buffer */
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char *nextc; /* next char in buffer */
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char *buf; /* input buffer */
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struct strpush *strpush; /* for pushing strings at this level */
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struct strpush basestrpush; /* so pushing one is fast */
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};
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int plinno = 1; /* input line number */
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MKINIT int parsenleft; /* copy of parsefile->nleft */
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MKINIT int parselleft; /* copy of parsefile->lleft */
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char *parsenextc; /* copy of parsefile->nextc */
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MKINIT struct parsefile basepf; /* top level input file */
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char basebuf[BUFSIZ]; /* buffer for top level input file */
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STATIC struct parsefile *parsefile = &basepf; /* current input file */
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int init_editline = 0; /* editline library initialized? */
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int whichprompt; /* 1 == PS1, 2 == PS2 */
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EditLine *el; /* cookie for editline package */
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STATIC void pushfile(void);
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static int preadfd(void);
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#ifdef mkinit
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INCLUDE "input.h"
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INCLUDE "error.h"
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INIT {
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extern char basebuf[];
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basepf.nextc = basepf.buf = basebuf;
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}
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RESET {
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if (exception != EXSHELLPROC)
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parselleft = parsenleft = 0; /* clear input buffer */
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popallfiles();
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}
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SHELLPROC {
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popallfiles();
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}
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#endif
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/*
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* Read a line from the script.
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*/
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char *
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pfgets(char *line, int len)
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{
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char *p = line;
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int nleft = len;
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int c;
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while (--nleft > 0) {
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c = pgetc_macro();
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if (c == PEOF) {
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if (p == line)
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return NULL;
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break;
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}
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*p++ = c;
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if (c == '\n')
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break;
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}
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*p = '\0';
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return line;
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}
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/*
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* Read a character from the script, returning PEOF on end of file.
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* Nul characters in the input are silently discarded.
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*/
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int
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pgetc(void)
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{
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return pgetc_macro();
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}
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static int
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preadfd(void)
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{
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int nr;
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parsenextc = parsefile->buf;
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#ifndef NO_HISTORY
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if (el != NULL && gotwinch) {
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gotwinch = 0;
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el_resize(el);
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}
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#endif
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retry:
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#ifndef NO_HISTORY
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if (parsefile->fd == 0 && el) {
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static const char *rl_cp;
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static int el_len;
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if (rl_cp == NULL)
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rl_cp = el_gets(el, &el_len);
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if (rl_cp == NULL)
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nr = 0;
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else {
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nr = el_len;
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if (nr > BUFSIZ - 1)
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nr = BUFSIZ - 1;
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memcpy(parsenextc, rl_cp, nr);
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if (nr != el_len) {
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el_len -= nr;
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rl_cp += nr;
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} else
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rl_cp = NULL;
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}
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} else
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#endif
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nr = read(parsefile->fd, parsenextc, BUFSIZ - 1);
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if (nr <= 0) {
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if (nr < 0) {
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if (errno == EINTR)
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goto retry;
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if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
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int flags = fcntl(0, F_GETFL, 0);
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if (flags >= 0 && flags & O_NONBLOCK) {
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flags &=~ O_NONBLOCK;
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if (fcntl(0, F_SETFL, flags) >= 0) {
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out2str("sh: turning off NDELAY mode\n");
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goto retry;
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}
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}
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}
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}
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nr = -1;
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}
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return nr;
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}
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/*
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* Refill the input buffer and return the next input character:
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*
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* 1) If a string was pushed back on the input, pop it;
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* 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
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* from a string so we can't refill the buffer, return EOF.
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* 3) If there is more in this buffer, use it else call read to fill it.
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* 4) Process input up to the next newline, deleting nul characters.
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*/
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int
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preadbuffer(void)
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{
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char *p, *q;
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int more;
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int something;
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char savec;
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if (parsefile->strpush) {
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popstring();
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if (--parsenleft >= 0)
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return (*parsenextc++);
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}
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if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
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return PEOF;
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flushout(&output);
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flushout(&errout);
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again:
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if (parselleft <= 0) {
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if ((parselleft = preadfd()) == -1) {
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parselleft = parsenleft = EOF_NLEFT;
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return PEOF;
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}
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}
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q = p = parsenextc;
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/* delete nul characters */
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something = 0;
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for (more = 1; more;) {
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switch (*p) {
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case '\0':
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p++; /* Skip nul */
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goto check;
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case '\t':
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case ' ':
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break;
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case '\n':
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parsenleft = q - parsenextc;
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more = 0; /* Stop processing here */
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break;
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default:
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something = 1;
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break;
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}
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*q++ = *p++;
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check:
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if (--parselleft <= 0) {
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parsenleft = q - parsenextc - 1;
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if (parsenleft < 0)
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goto again;
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*q = '\0';
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more = 0;
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}
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}
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savec = *q;
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*q = '\0';
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#ifndef NO_HISTORY
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if (parsefile->fd == 0 && hist && something) {
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HistEvent he;
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INTOFF;
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history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
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parsenextc);
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INTON;
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}
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#endif
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if (vflag) {
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out2str(parsenextc);
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flushout(out2);
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}
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*q = savec;
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return *parsenextc++;
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}
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/*
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* Returns if we are certain we are at EOF. Does not cause any more input
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* to be read from the outside world.
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*/
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int
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preadateof(void)
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{
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if (parsenleft > 0)
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return 0;
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if (parsefile->strpush)
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return 0;
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if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
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return 1;
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return 0;
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}
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/*
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* Undo the last call to pgetc. Only one character may be pushed back.
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* PEOF may be pushed back.
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*/
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void
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pungetc(void)
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{
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parsenleft++;
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parsenextc--;
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}
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/*
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* Push a string back onto the input at this current parsefile level.
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* We handle aliases this way.
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*/
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void
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pushstring(char *s, int len, void *ap)
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{
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struct strpush *sp;
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INTOFF;
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/*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
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if (parsefile->strpush) {
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sp = ckmalloc(sizeof (struct strpush));
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sp->prev = parsefile->strpush;
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parsefile->strpush = sp;
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} else
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sp = parsefile->strpush = &(parsefile->basestrpush);
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sp->prevstring = parsenextc;
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sp->prevnleft = parsenleft;
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sp->prevlleft = parselleft;
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sp->ap = (struct alias *)ap;
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if (ap)
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((struct alias *)ap)->flag |= ALIASINUSE;
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parsenextc = s;
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parsenleft = len;
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INTON;
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}
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void
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popstring(void)
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{
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struct strpush *sp = parsefile->strpush;
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INTOFF;
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parsenextc = sp->prevstring;
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parsenleft = sp->prevnleft;
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parselleft = sp->prevlleft;
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/*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
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if (sp->ap)
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sp->ap->flag &= ~ALIASINUSE;
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parsefile->strpush = sp->prev;
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if (sp != &(parsefile->basestrpush))
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ckfree(sp);
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INTON;
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}
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/*
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* Set the input to take input from a file. If push is set, push the
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* old input onto the stack first.
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*/
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void
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setinputfile(char *fname, int push)
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{
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int fd;
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int fd2;
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INTOFF;
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if ((fd = open(fname, O_RDONLY)) < 0)
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error("Can't open %s: %s", fname, strerror(errno));
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if (fd < 10) {
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fd2 = fcntl(fd, F_DUPFD, 10);
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close(fd);
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if (fd2 < 0)
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error("Out of file descriptors");
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fd = fd2;
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}
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setinputfd(fd, push);
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INTON;
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}
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/*
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* Like setinputfile, but takes an open file descriptor. Call this with
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* interrupts off.
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*/
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void
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setinputfd(int fd, int push)
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{
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(void)fcntl(fd, F_SETFD, FD_CLOEXEC);
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if (push) {
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pushfile();
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parsefile->buf = ckmalloc(BUFSIZ);
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}
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if (parsefile->fd > 0)
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close(parsefile->fd);
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parsefile->fd = fd;
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if (parsefile->buf == NULL)
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parsefile->buf = ckmalloc(BUFSIZ);
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parselleft = parsenleft = 0;
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plinno = 1;
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}
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/*
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* Like setinputfile, but takes input from a string.
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*/
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void
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setinputstring(char *string, int push)
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{
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INTOFF;
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if (push)
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pushfile();
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parsenextc = string;
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parselleft = parsenleft = strlen(string);
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parsefile->buf = NULL;
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plinno = 1;
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INTON;
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}
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/*
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* To handle the "." command, a stack of input files is used. Pushfile
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* adds a new entry to the stack and popfile restores the previous level.
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*/
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STATIC void
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pushfile(void)
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{
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struct parsefile *pf;
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parsefile->nleft = parsenleft;
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parsefile->lleft = parselleft;
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parsefile->nextc = parsenextc;
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parsefile->linno = plinno;
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pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
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pf->prev = parsefile;
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pf->fd = -1;
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pf->strpush = NULL;
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pf->basestrpush.prev = NULL;
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parsefile = pf;
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}
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void
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popfile(void)
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{
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struct parsefile *pf = parsefile;
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INTOFF;
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if (pf->fd >= 0)
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close(pf->fd);
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if (pf->buf)
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ckfree(pf->buf);
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while (pf->strpush)
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popstring();
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parsefile = pf->prev;
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ckfree(pf);
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parsenleft = parsefile->nleft;
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parselleft = parsefile->lleft;
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parsenextc = parsefile->nextc;
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plinno = parsefile->linno;
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INTON;
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}
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/*
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* Return to top level.
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*/
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void
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popallfiles(void)
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{
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while (parsefile != &basepf)
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popfile();
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}
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/*
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* Close the file(s) that the shell is reading commands from. Called
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* after a fork is done.
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*/
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void
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closescript(void)
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{
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popallfiles();
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if (parsefile->fd > 0) {
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close(parsefile->fd);
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parsefile->fd = 0;
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}
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}
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