4783843fdc
the non-vfork case. Having said that, it would be nice if pipelines of simple commands were vforked too. Right now they are not. Explain that setpgid() might fail because we are doing it both in the parent and the child case, because we don't know which one will come first. Suspending a pipeline prints %1 Suspended n times where n is the number of processes, but that was there before. It is easy to fix, but I'll leave the code alone for now.
393 lines
8.6 KiB
C
393 lines
8.6 KiB
C
/* $NetBSD: redir.c,v 1.26 2002/09/28 01:25:02 christos Exp $ */
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/*-
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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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* 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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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95";
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#else
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__RCSID("$NetBSD: redir.c,v 1.26 2002/09/28 01:25:02 christos Exp $");
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#endif
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#endif /* not lint */
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#include <sys/types.h>
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#include <sys/param.h> /* PIPE_BUF */
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#include <signal.h>
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#include <string.h>
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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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/*
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* Code for dealing with input/output redirection.
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*/
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#include "main.h"
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#include "shell.h"
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#include "nodes.h"
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#include "jobs.h"
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#include "options.h"
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#include "expand.h"
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#include "redir.h"
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#include "output.h"
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#include "memalloc.h"
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#include "error.h"
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#define EMPTY -2 /* marks an unused slot in redirtab */
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#ifndef PIPE_BUF
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# define PIPESIZE 4096 /* amount of buffering in a pipe */
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#else
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# define PIPESIZE PIPE_BUF
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#endif
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MKINIT
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struct redirtab {
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struct redirtab *next;
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short renamed[10];
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};
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MKINIT struct redirtab *redirlist;
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/*
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* We keep track of whether or not fd0 has been redirected. This is for
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* background commands, where we want to redirect fd0 to /dev/null only
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* if it hasn't already been redirected.
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*/
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int fd0_redirected = 0;
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STATIC void openredirect __P((union node *, char[10 ]));
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STATIC int openhere __P((union node *));
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/*
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* Process a list of redirection commands. If the REDIR_PUSH flag is set,
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* old file descriptors are stashed away so that the redirection can be
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* undone by calling popredir. If the REDIR_BACKQ flag is set, then the
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* standard output, and the standard error if it becomes a duplicate of
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* stdout, is saved in memory.
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*/
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void
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redirect(redir, flags)
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union node *redir;
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int flags;
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{
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union node *n;
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struct redirtab *sv = NULL;
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int i;
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int fd;
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int try;
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char memory[10]; /* file descriptors to write to memory */
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for (i = 10 ; --i >= 0 ; )
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memory[i] = 0;
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memory[1] = flags & REDIR_BACKQ;
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if (flags & REDIR_PUSH) {
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/* We don't have to worry about REDIR_VFORK here, as
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* flags & REDIR_PUSH is never true if REDIR_VFORK is set.
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*/
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sv = ckmalloc(sizeof (struct redirtab));
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for (i = 0 ; i < 10 ; i++)
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sv->renamed[i] = EMPTY;
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sv->next = redirlist;
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redirlist = sv;
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}
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for (n = redir ; n ; n = n->nfile.next) {
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fd = n->nfile.fd;
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try = 0;
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if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
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n->ndup.dupfd == fd)
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continue; /* redirect from/to same file descriptor */
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if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
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INTOFF;
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again:
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if ((i = fcntl(fd, F_DUPFD, 10)) == -1) {
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switch (errno) {
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case EBADF:
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if (!try) {
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openredirect(n, memory);
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try++;
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goto again;
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}
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/* FALLTHROUGH*/
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default:
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INTON;
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error("%d: %s", fd, strerror(errno));
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/* NOTREACHED */
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}
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}
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if (!try) {
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sv->renamed[fd] = i;
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close(fd);
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}
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INTON;
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} else {
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close(fd);
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}
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if (fd == 0)
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fd0_redirected++;
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if (!try)
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openredirect(n, memory);
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}
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if (memory[1])
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out1 = &memout;
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if (memory[2])
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out2 = &memout;
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}
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STATIC void
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openredirect(redir, memory)
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union node *redir;
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char memory[10];
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{
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int fd = redir->nfile.fd;
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char *fname;
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int f;
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int flags = O_WRONLY|O_CREAT|O_TRUNC;
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/*
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* We suppress interrupts so that we won't leave open file
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* descriptors around. This may not be such a good idea because
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* an open of a device or a fifo can block indefinitely.
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*/
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INTOFF;
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memory[fd] = 0;
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switch (redir->nfile.type) {
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case NFROM:
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fname = redir->nfile.expfname;
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if ((f = open(fname, O_RDONLY)) < 0)
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goto eopen;
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break;
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case NFROMTO:
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fname = redir->nfile.expfname;
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if ((f = open(fname, O_RDWR|O_CREAT|O_TRUNC, 0666)) < 0)
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goto ecreate;
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break;
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case NTO:
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if (Cflag)
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flags |= O_EXCL;
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/* FALLTHROUGH */
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case NCLOBBER:
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fname = redir->nfile.expfname;
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if ((f = open(fname, flags, 0666)) < 0)
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goto ecreate;
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break;
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case NAPPEND:
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fname = redir->nfile.expfname;
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if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
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goto ecreate;
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break;
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case NTOFD:
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case NFROMFD:
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if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
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if (memory[redir->ndup.dupfd])
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memory[fd] = 1;
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else
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copyfd(redir->ndup.dupfd, fd);
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}
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INTON;
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return;
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case NHERE:
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case NXHERE:
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f = openhere(redir);
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break;
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default:
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abort();
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}
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if (f != fd) {
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copyfd(f, fd);
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close(f);
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}
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INTON;
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return;
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ecreate:
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error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
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eopen:
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error("cannot open %s: %s", fname, errmsg(errno, E_OPEN));
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}
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/*
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* Handle here documents. Normally we fork off a process to write the
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* data to a pipe. If the document is short, we can stuff the data in
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* the pipe without forking.
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*/
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STATIC int
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openhere(redir)
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union node *redir;
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{
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int pip[2];
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int len = 0;
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if (pipe(pip) < 0)
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error("Pipe call failed");
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if (redir->type == NHERE) {
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len = strlen(redir->nhere.doc->narg.text);
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if (len <= PIPESIZE) {
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xwrite(pip[1], redir->nhere.doc->narg.text, len);
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goto out;
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}
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}
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if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
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close(pip[0]);
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signal(SIGINT, SIG_IGN);
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signal(SIGQUIT, SIG_IGN);
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signal(SIGHUP, SIG_IGN);
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#ifdef SIGTSTP
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signal(SIGTSTP, SIG_IGN);
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#endif
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signal(SIGPIPE, SIG_DFL);
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if (redir->type == NHERE)
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xwrite(pip[1], redir->nhere.doc->narg.text, len);
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else
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expandhere(redir->nhere.doc, pip[1]);
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_exit(0);
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}
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out:
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close(pip[1]);
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return pip[0];
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}
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/*
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* Undo the effects of the last redirection.
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*/
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void
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popredir() {
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struct redirtab *rp = redirlist;
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int i;
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for (i = 0 ; i < 10 ; i++) {
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if (rp->renamed[i] != EMPTY) {
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if (i == 0)
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fd0_redirected--;
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close(i);
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if (rp->renamed[i] >= 0) {
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copyfd(rp->renamed[i], i);
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close(rp->renamed[i]);
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}
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}
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}
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INTOFF;
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redirlist = rp->next;
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ckfree(rp);
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INTON;
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}
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/*
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* Undo all redirections. Called on error or interrupt.
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*/
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#ifdef mkinit
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INCLUDE "redir.h"
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RESET {
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while (redirlist)
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popredir();
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}
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SHELLPROC {
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clearredir(0);
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}
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#endif
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/* Return true if fd 0 has already been redirected at least once. */
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int
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fd0_redirected_p () {
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return fd0_redirected != 0;
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}
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/*
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* Discard all saved file descriptors.
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*/
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void
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clearredir(vforked)
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int vforked;
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{
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struct redirtab *rp;
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int i;
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for (rp = redirlist ; rp ; rp = rp->next) {
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for (i = 0 ; i < 10 ; i++) {
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if (rp->renamed[i] >= 0) {
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close(rp->renamed[i]);
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}
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if (!vforked)
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rp->renamed[i] = EMPTY;
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}
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}
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}
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/*
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* Copy a file descriptor to be >= to. Returns -1
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* if the source file descriptor is closed, EMPTY if there are no unused
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* file descriptors left.
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*/
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int
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copyfd(from, to)
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int from;
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int to;
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{
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int newfd;
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newfd = fcntl(from, F_DUPFD, to);
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if (newfd < 0) {
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if (errno == EMFILE)
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return EMPTY;
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else
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error("%d: %s", from, strerror(errno));
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}
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return newfd;
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}
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