auto import from //depot/cupcake/@135843
diff --git a/sh/redir.c b/sh/redir.c
new file mode 100644
index 0000000..5c4c286
--- /dev/null
+++ b/sh/redir.c
@@ -0,0 +1,389 @@
+/* $NetBSD: redir.c,v 1.29 2004/07/08 03:57:33 christos Exp $ */
+
+/*-
+ * Copyright (c) 1991, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * 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.
+ * 3. 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>
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95";
+#else
+__RCSID("$NetBSD: redir.c,v 1.29 2004/07/08 03:57:33 christos Exp $");
+#endif
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/param.h> /* PIPE_BUF */
+#include <signal.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+/*
+ * Code for dealing with input/output redirection.
+ */
+
+#include "main.h"
+#include "shell.h"
+#include "nodes.h"
+#include "jobs.h"
+#include "options.h"
+#include "expand.h"
+#include "redir.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+
+
+#define EMPTY -2 /* marks an unused slot in redirtab */
+#ifndef PIPE_BUF
+# define PIPESIZE 4096 /* amount of buffering in a pipe */
+#else
+# define PIPESIZE PIPE_BUF
+#endif
+
+#define signal bsd_signal
+
+MKINIT
+struct redirtab {
+ struct redirtab *next;
+ short renamed[10];
+};
+
+
+MKINIT struct redirtab *redirlist;
+
+/*
+ * We keep track of whether or not fd0 has been redirected. This is for
+ * background commands, where we want to redirect fd0 to /dev/null only
+ * if it hasn't already been redirected.
+*/
+int fd0_redirected = 0;
+
+STATIC void openredirect(union node *, char[10], int);
+STATIC int openhere(union node *);
+
+
+/*
+ * Process a list of redirection commands. If the REDIR_PUSH flag is set,
+ * old file descriptors are stashed away so that the redirection can be
+ * undone by calling popredir. If the REDIR_BACKQ flag is set, then the
+ * standard output, and the standard error if it becomes a duplicate of
+ * stdout, is saved in memory.
+ */
+
+void
+redirect(union node *redir, int flags)
+{
+ union node *n;
+ struct redirtab *sv = NULL;
+ int i;
+ int fd;
+ int try;
+ char memory[10]; /* file descriptors to write to memory */
+
+ for (i = 10 ; --i >= 0 ; )
+ memory[i] = 0;
+ memory[1] = flags & REDIR_BACKQ;
+ if (flags & REDIR_PUSH) {
+ /* We don't have to worry about REDIR_VFORK here, as
+ * flags & REDIR_PUSH is never true if REDIR_VFORK is set.
+ */
+ sv = ckmalloc(sizeof (struct redirtab));
+ for (i = 0 ; i < 10 ; i++)
+ sv->renamed[i] = EMPTY;
+ sv->next = redirlist;
+ redirlist = sv;
+ }
+ for (n = redir ; n ; n = n->nfile.next) {
+ fd = n->nfile.fd;
+ try = 0;
+ if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
+ n->ndup.dupfd == fd)
+ continue; /* redirect from/to same file descriptor */
+
+ if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
+ INTOFF;
+again:
+ if ((i = fcntl(fd, F_DUPFD, 10)) == -1) {
+ switch (errno) {
+ case EBADF:
+ if (!try) {
+ openredirect(n, memory, flags);
+ try++;
+ goto again;
+ }
+ /* FALLTHROUGH*/
+ default:
+ INTON;
+ error("%d: %s", fd, strerror(errno));
+ /* NOTREACHED */
+ }
+ }
+ if (!try) {
+ sv->renamed[fd] = i;
+ close(fd);
+ }
+ INTON;
+ } else {
+ close(fd);
+ }
+ if (fd == 0)
+ fd0_redirected++;
+ if (!try)
+ openredirect(n, memory, flags);
+ }
+ if (memory[1])
+ out1 = &memout;
+ if (memory[2])
+ out2 = &memout;
+}
+
+
+STATIC void
+openredirect(union node *redir, char memory[10], int flags)
+{
+ int fd = redir->nfile.fd;
+ char *fname;
+ int f;
+ int oflags = O_WRONLY|O_CREAT|O_TRUNC, eflags;
+
+ /*
+ * We suppress interrupts so that we won't leave open file
+ * descriptors around. This may not be such a good idea because
+ * an open of a device or a fifo can block indefinitely.
+ */
+ INTOFF;
+ memory[fd] = 0;
+ switch (redir->nfile.type) {
+ case NFROM:
+ fname = redir->nfile.expfname;
+ if (flags & REDIR_VFORK)
+ eflags = O_NONBLOCK;
+ else
+ eflags = 0;
+ if ((f = open(fname, O_RDONLY|eflags)) < 0)
+ goto eopen;
+ if (eflags)
+ (void)fcntl(f, F_SETFL, fcntl(f, F_GETFL, 0) & ~eflags);
+ break;
+ case NFROMTO:
+ fname = redir->nfile.expfname;
+ if ((f = open(fname, O_RDWR|O_CREAT|O_TRUNC, 0666)) < 0)
+ goto ecreate;
+ break;
+ case NTO:
+ if (Cflag)
+ oflags |= O_EXCL;
+ /* FALLTHROUGH */
+ case NCLOBBER:
+ fname = redir->nfile.expfname;
+ if ((f = open(fname, oflags, 0666)) < 0)
+ goto ecreate;
+ break;
+ case NAPPEND:
+ fname = redir->nfile.expfname;
+ if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
+ goto ecreate;
+ break;
+ case NTOFD:
+ case NFROMFD:
+ if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
+ if (memory[redir->ndup.dupfd])
+ memory[fd] = 1;
+ else
+ copyfd(redir->ndup.dupfd, fd);
+ }
+ INTON;
+ return;
+ case NHERE:
+ case NXHERE:
+ f = openhere(redir);
+ break;
+ default:
+ abort();
+ }
+
+ if (f != fd) {
+ copyfd(f, fd);
+ close(f);
+ }
+ INTON;
+ return;
+ecreate:
+ error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
+eopen:
+ error("cannot open %s: %s", fname, errmsg(errno, E_OPEN));
+}
+
+
+/*
+ * Handle here documents. Normally we fork off a process to write the
+ * data to a pipe. If the document is short, we can stuff the data in
+ * the pipe without forking.
+ */
+
+STATIC int
+openhere(union node *redir)
+{
+ int pip[2];
+ int len = 0;
+
+ if (pipe(pip) < 0)
+ error("Pipe call failed");
+ if (redir->type == NHERE) {
+ len = strlen(redir->nhere.doc->narg.text);
+ if (len <= PIPESIZE) {
+ xwrite(pip[1], redir->nhere.doc->narg.text, len);
+ goto out;
+ }
+ }
+ if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
+ close(pip[0]);
+ signal(SIGINT, SIG_IGN);
+ signal(SIGQUIT, SIG_IGN);
+ signal(SIGHUP, SIG_IGN);
+#ifdef SIGTSTP
+ signal(SIGTSTP, SIG_IGN);
+#endif
+ signal(SIGPIPE, SIG_DFL);
+ if (redir->type == NHERE)
+ xwrite(pip[1], redir->nhere.doc->narg.text, len);
+ else
+ expandhere(redir->nhere.doc, pip[1]);
+ _exit(0);
+ }
+out:
+ close(pip[1]);
+ return pip[0];
+}
+
+
+
+/*
+ * Undo the effects of the last redirection.
+ */
+
+void
+popredir(void)
+{
+ struct redirtab *rp = redirlist;
+ int i;
+
+ for (i = 0 ; i < 10 ; i++) {
+ if (rp->renamed[i] != EMPTY) {
+ if (i == 0)
+ fd0_redirected--;
+ close(i);
+ if (rp->renamed[i] >= 0) {
+ copyfd(rp->renamed[i], i);
+ close(rp->renamed[i]);
+ }
+ }
+ }
+ INTOFF;
+ redirlist = rp->next;
+ ckfree(rp);
+ INTON;
+}
+
+/*
+ * Undo all redirections. Called on error or interrupt.
+ */
+
+#ifdef mkinit
+
+INCLUDE "redir.h"
+
+RESET {
+ while (redirlist)
+ popredir();
+}
+
+SHELLPROC {
+ clearredir(0);
+}
+
+#endif
+
+/* Return true if fd 0 has already been redirected at least once. */
+int
+fd0_redirected_p () {
+ return fd0_redirected != 0;
+}
+
+/*
+ * Discard all saved file descriptors.
+ */
+
+void
+clearredir(vforked)
+ int vforked;
+{
+ struct redirtab *rp;
+ int i;
+
+ for (rp = redirlist ; rp ; rp = rp->next) {
+ for (i = 0 ; i < 10 ; i++) {
+ if (rp->renamed[i] >= 0) {
+ close(rp->renamed[i]);
+ }
+ if (!vforked)
+ rp->renamed[i] = EMPTY;
+ }
+ }
+}
+
+
+
+/*
+ * Copy a file descriptor to be >= to. Returns -1
+ * if the source file descriptor is closed, EMPTY if there are no unused
+ * file descriptors left.
+ */
+
+int
+copyfd(int from, int to)
+{
+ int newfd;
+
+ newfd = fcntl(from, F_DUPFD, to);
+ if (newfd < 0) {
+ if (errno == EMFILE)
+ return EMPTY;
+ else
+ error("%d: %s", from, strerror(errno));
+ }
+ return newfd;
+}