initial population

1 files changed, 982 insertions, 0 deletions

diff --git a/bin/sh/redir.c b/bin/sh/redir.c
new file mode 100644
index 0000000..751cce7
--- /dev/null
+++ b/bin/sh/redir.c
@@ -0,0 +1,982 @@
+/*	$NetBSD: redir.c,v 1.62 2018/11/26 20:03:39 kamil 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 1.62 2018/11/26 20:03:39 kamil Exp $");
+#endif
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/param.h>	/* PIPE_BUF */
+#include <sys/stat.h>
+#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 "builtins.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 "mystring.h"
+#include "error.h"
+#include "show.h"
+
+
+#define EMPTY -2		/* marks an unused slot in redirtab */
+#define CLOSED -1		/* fd was not open before redir */
+#ifndef PIPE_BUF
+# define PIPESIZE 4096		/* amount of buffering in a pipe */
+#else
+# define PIPESIZE PIPE_BUF
+#endif
+
+
+MKINIT
+struct renamelist {
+	struct renamelist *next;
+	int orig;
+	int into;
+};
+
+MKINIT
+struct redirtab {
+	struct redirtab *next;
+	struct renamelist *renamed;
+};
+
+
+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.
+ */
+STATIC int fd0_redirected = 0;
+
+/*
+ * And also where to put internal use fds that should be out of the
+ * way of user defined fds (normally)
+ */
+STATIC int big_sh_fd = 0;
+
+STATIC const struct renamelist *is_renamed(const struct renamelist *, int);
+STATIC void fd_rename(struct redirtab *, int, int);
+STATIC void free_rl(struct redirtab *, int);
+STATIC void openredirect(union node *, char[10], int);
+STATIC int openhere(const union node *);
+STATIC int copyfd(int, int, int);
+STATIC void find_big_fd(void);
+
+
+struct shell_fds {		/* keep track of internal shell fds */
+	struct shell_fds *nxt;
+	void (*cb)(int, int);
+	int fd;
+};
+
+STATIC struct shell_fds *sh_fd_list;
+
+STATIC void renumber_sh_fd(struct shell_fds *);
+STATIC struct shell_fds *sh_fd(int);
+
+STATIC const struct renamelist *
+is_renamed(const struct renamelist *rl, int fd)
+{
+	while (rl != NULL) {
+		if (rl->orig == fd)
+			return rl;
+		rl = rl->next;
+	}
+	return NULL;
+}
+
+STATIC void
+free_rl(struct redirtab *rt, int reset)
+{
+	struct renamelist *rl, *rn = rt->renamed;
+
+	while ((rl = rn) != NULL) {
+		rn = rl->next;
+		if (rl->orig == 0)
+			fd0_redirected--;
+		VTRACE(DBG_REDIR, ("popredir %d%s: %s",
+		    rl->orig, rl->orig==0 ? " (STDIN)" : "",
+		    reset ? "" : "no reset\n"));
+		if (reset) {
+			if (rl->into < 0) {
+				VTRACE(DBG_REDIR, ("closed\n"));
+				close(rl->orig);
+			} else {
+				VTRACE(DBG_REDIR, ("from %d\n", rl->into));
+				movefd(rl->into, rl->orig);
+			}
+		}
+		ckfree(rl);
+	}
+	rt->renamed = NULL;
+}
+
+STATIC void
+fd_rename(struct redirtab *rt, int from, int to)
+{
+	/* XXX someday keep a short list (8..10) of freed renamelists XXX */
+	struct renamelist *rl = ckmalloc(sizeof(struct renamelist));
+
+	rl->next = rt->renamed;
+	rt->renamed = rl;
+
+	rl->orig = from;
+	rl->into = to;
+}
+
+/*
+ * 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;
+	char memory[10];	/* file descriptors to write to memory */
+
+	CTRACE(DBG_REDIR, ("redirect(F=0x%x):%s\n", flags, redir?"":" NONE"));
+	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));
+		sv->renamed = NULL;
+		sv->next = redirlist;
+		redirlist = sv;
+	}
+	for (n = redir ; n ; n = n->nfile.next) {
+		fd = n->nfile.fd;
+		VTRACE(DBG_REDIR, ("redir %d (max=%d) ", fd, max_user_fd));
+		if (fd > max_user_fd)
+			max_user_fd = fd;
+		renumber_sh_fd(sh_fd(fd));
+		if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
+		    n->ndup.dupfd == fd) {
+			/* redirect from/to same file descriptor */
+			/* make sure it stays open */
+			if (fcntl(fd, F_SETFD, 0) < 0)
+				error("fd %d: %s", fd, strerror(errno));
+			VTRACE(DBG_REDIR, ("!cloexec\n"));
+			continue;
+		}
+
+		if ((flags & REDIR_PUSH) && !is_renamed(sv->renamed, fd)) {
+			INTOFF;
+			if (big_sh_fd < 10)
+				find_big_fd();
+			if ((i = fcntl(fd, F_DUPFD, big_sh_fd)) == -1) {
+				switch (errno) {
+				case EBADF:
+					i = CLOSED;
+					break;
+				case EMFILE:
+				case EINVAL:
+					find_big_fd();
+					i = fcntl(fd, F_DUPFD, big_sh_fd);
+					if (i >= 0)
+						break;
+					/* FALLTHRU */
+				default:
+					i = errno;
+					INTON;    /* XXX not needed here ? */
+					error("%d: %s", fd, strerror(i));
+					/* NOTREACHED */
+				}
+			}
+			if (i >= 0)
+				(void)fcntl(i, F_SETFD, FD_CLOEXEC);
+			fd_rename(sv, fd, i);
+			VTRACE(DBG_REDIR, ("saved as %d ", i));
+			INTON;
+		}
+		VTRACE(DBG_REDIR, ("%s\n", fd == 0 ? "STDIN" : ""));
+		if (fd == 0)
+			fd0_redirected++;
+		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)
+{
+	struct stat sb;
+	int fd = redir->nfile.fd;
+	char *fname;
+	int f;
+	int eflags, cloexec;
+
+	/*
+	 * 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;
+	if (fd < 10)
+		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;
+		VTRACE(DBG_REDIR, ("openredirect(< '%s') -> %d [%#x]",
+		    fname, f, eflags));
+		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, 0666)) < 0)
+			goto ecreate;
+		VTRACE(DBG_REDIR, ("openredirect(<> '%s') -> %d", fname, f));
+		break;
+	case NTO:
+		if (Cflag) {
+			fname = redir->nfile.expfname;
+			if ((f = open(fname, O_WRONLY)) == -1) {
+				if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL,
+				    0666)) < 0)
+					goto ecreate;
+			} else if (fstat(f, &sb) == -1) {
+				int serrno = errno;
+				close(f);
+				errno = serrno;
+				goto ecreate;
+			} else if (S_ISREG(sb.st_mode)) {
+				close(f);
+				errno = EEXIST;
+				goto ecreate;
+			}
+			VTRACE(DBG_REDIR, ("openredirect(>| '%s') -> %d",
+			    fname, f));
+			break;
+		}
+		/* FALLTHROUGH */
+	case NCLOBBER:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
+			goto ecreate;
+		VTRACE(DBG_REDIR, ("openredirect(> '%s') -> %d", fname, f));
+		break;
+	case NAPPEND:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
+			goto ecreate;
+		VTRACE(DBG_REDIR, ("openredirect(>> '%s') -> %d", fname, f));
+		break;
+	case NTOFD:
+	case NFROMFD:
+		if (redir->ndup.dupfd >= 0) {	/* if not ">&-" */
+			if (fd < 10 && redir->ndup.dupfd < 10 &&
+			    memory[redir->ndup.dupfd])
+				memory[fd] = 1;
+			else if (copyfd(redir->ndup.dupfd, fd,
+			    (flags & REDIR_KEEP) == 0) < 0)
+				error("Redirect (from %d to %d) failed: %s",
+				    redir->ndup.dupfd, fd, strerror(errno));
+			VTRACE(DBG_REDIR, ("openredirect: %d%c&%d\n", fd,
+			    "<>"[redir->nfile.type==NTOFD], redir->ndup.dupfd));
+		} else {
+			(void) close(fd);
+			VTRACE(DBG_REDIR, ("openredirect: %d%c&-\n", fd,
+			    "<>"[redir->nfile.type==NTOFD]));
+		}
+		INTON;
+		return;
+	case NHERE:
+	case NXHERE:
+		VTRACE(DBG_REDIR, ("openredirect: %d<<...", fd));
+		f = openhere(redir);
+		break;
+	default:
+		abort();
+	}
+
+	cloexec = fd > 2 && (flags & REDIR_KEEP) == 0 && !posix;
+	if (f != fd) {
+		VTRACE(DBG_REDIR, (" -> %d", fd));
+		if (copyfd(f, fd, cloexec) < 0) {
+			int e = errno;
+
+			close(f);
+			error("redirect reassignment (fd %d) failed: %s", fd,
+			    strerror(e));
+		}
+		close(f);
+	} else if (cloexec)
+		(void)fcntl(f, F_SETFD, FD_CLOEXEC);
+	VTRACE(DBG_REDIR, ("%s\n", cloexec ? " cloexec" : ""));
+
+	INTON;
+	return;
+ ecreate:
+	exerrno = 1;
+	error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
+ eopen:
+	exerrno = 1;
+	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(const 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;
+		}
+	}
+	VTRACE(DBG_REDIR, (" forking [%d,%d]\n", pip[0], pip[1]));
+	if (forkshell(NULL, 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);
+	}
+	VTRACE(DBG_REDIR, ("openhere (closing %d)", pip[1]));
+ out:
+	close(pip[1]);
+	VTRACE(DBG_REDIR, (" (pipe fd=%d)", pip[0]));
+	return pip[0];
+}
+
+
+
+/*
+ * Undo the effects of the last redirection.
+ */
+
+void
+popredir(void)
+{
+	struct redirtab *rp = redirlist;
+
+	INTOFF;
+	free_rl(rp, 1);
+	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(void)
+{
+	return fd0_redirected != 0;
+}
+
+/*
+ * Discard all saved file descriptors.
+ */
+
+void
+clearredir(int vforked)
+{
+	struct redirtab *rp;
+	struct renamelist *rl;
+
+	for (rp = redirlist ; rp ; rp = rp->next) {
+		if (!vforked)
+			free_rl(rp, 0);
+		else for (rl = rp->renamed; rl; rl = rl->next)
+			if (rl->into >= 0)
+				close(rl->into);
+	}
+}
+
+
+
+/*
+ * Copy a file descriptor to be == to.
+ * cloexec indicates if we want close-on-exec or not.
+ * Returns -1 if any error occurs.
+ */
+
+STATIC int
+copyfd(int from, int to, int cloexec)
+{
+	int newfd;
+
+	if (cloexec && to > 2)
+		newfd = dup3(from, to, O_CLOEXEC);
+	else
+		newfd = dup2(from, to);
+
+	return newfd;
+}
+
+/*
+ * rename fd from to be fd to (closing from).
+ * close-on-exec is never set on 'to' (unless
+ * from==to and it was set on from) - ie: a no-op
+ * returns to (or errors() if an error occurs).
+ *
+ * This is mostly used for rearranging the
+ * results from pipe().
+ */
+int
+movefd(int from, int to)
+{
+	if (from == to)
+		return to;
+
+	(void) close(to);
+	if (copyfd(from, to, 0) != to) {
+		int e = errno;
+
+		(void) close(from);
+		error("Unable to make fd %d: %s", to, strerror(e));
+	}
+	(void) close(from);
+
+	return to;
+}
+
+STATIC void
+find_big_fd(void)
+{
+	int i, fd;
+	static int last_start = 3; /* aim to keep sh fd's under 20 */
+
+	if (last_start < 10)
+		last_start++;
+
+	for (i = (1 << last_start); i >= 10; i >>= 1) {
+		if ((fd = fcntl(0, F_DUPFD, i - 1)) >= 0) {
+			close(fd);
+			break;
+		}
+	}
+
+	fd = (i / 5) * 4;
+	if (fd < 10)
+		fd = 10;
+
+	big_sh_fd = fd;
+}
+
+/*
+ * If possible, move file descriptor fd out of the way
+ * of expected user fd values.   Returns the new fd
+ * (which may be the input fd if things do not go well.)
+ * Always set close-on-exec on the result, and close
+ * the input fd unless it is to be our result.
+ */
+int
+to_upper_fd(int fd)
+{
+	int i;
+
+	VTRACE(DBG_REDIR|DBG_OUTPUT, ("to_upper_fd(%d)", fd));
+	if (big_sh_fd < 10)
+		find_big_fd();
+	do {
+		i = fcntl(fd, F_DUPFD_CLOEXEC, big_sh_fd);
+		if (i >= 0) {
+			if (fd != i)
+				close(fd);
+			VTRACE(DBG_REDIR|DBG_OUTPUT, ("-> %d\n", i));
+			return i;
+		}
+		if (errno != EMFILE && errno != EINVAL)
+			break;
+		find_big_fd();
+	} while (big_sh_fd > 10);
+
+	/*
+	 * If we wanted to move this fd to some random high number
+	 * we certainly do not intend to pass it through exec, even
+	 * if the reassignment failed.
+	 */
+	(void)fcntl(fd, F_SETFD, FD_CLOEXEC);
+	VTRACE(DBG_REDIR|DBG_OUTPUT, (" fails ->%d\n", fd));
+	return fd;
+}
+
+void
+register_sh_fd(int fd, void (*cb)(int, int))
+{
+	struct shell_fds *fp;
+
+	fp = ckmalloc(sizeof (struct shell_fds));
+	if (fp != NULL) {
+		fp->nxt = sh_fd_list;
+		sh_fd_list = fp;
+
+		fp->fd = fd;
+		fp->cb = cb;
+	}
+}
+
+void
+sh_close(int fd)
+{
+	struct shell_fds **fpp, *fp;
+
+	fpp = &sh_fd_list;
+	while ((fp = *fpp) != NULL) {
+		if (fp->fd == fd) {
+			*fpp = fp->nxt;
+			ckfree(fp);
+			break;
+		}
+		fpp = &fp->nxt;
+	}
+	(void)close(fd);
+}
+
+STATIC struct shell_fds *
+sh_fd(int fd)
+{
+	struct shell_fds *fp;
+
+	for (fp = sh_fd_list; fp != NULL; fp = fp->nxt)
+		if (fp->fd == fd)
+			return fp;
+	return NULL;
+}
+
+STATIC void
+renumber_sh_fd(struct shell_fds *fp)
+{
+	int to;
+
+	if (fp == NULL)
+		return;
+
+#ifndef	F_DUPFD_CLOEXEC
+#define	F_DUPFD_CLOEXEC	F_DUPFD
+#define	CLOEXEC(fd)	(fcntl((fd), F_SETFD, fcntl((fd),F_GETFD) | FD_CLOEXEC))
+#else
+#define	CLOEXEC(fd)
+#endif
+
+	/*
+	 * if we have had a collision, and the sh fd was a "big" one
+	 * try moving the sh fd base to a higher number (if possible)
+	 * so future sh fds are less likely to be in the user's sights
+	 * (incl this one when moved)
+	 */
+	if (fp->fd >= big_sh_fd)
+		find_big_fd();
+
+	to = fcntl(fp->fd, F_DUPFD_CLOEXEC, big_sh_fd);
+	if (to == -1)
+		to = fcntl(fp->fd, F_DUPFD_CLOEXEC, big_sh_fd/2);
+	if (to == -1)
+		to = fcntl(fp->fd, F_DUPFD_CLOEXEC, fp->fd + 1);
+	if (to == -1)
+		to = fcntl(fp->fd, F_DUPFD_CLOEXEC, 10);
+	if (to == -1)
+		to = fcntl(fp->fd, F_DUPFD_CLOEXEC, 3);
+	if (to == -1)
+		error("insufficient file descriptors available");
+	CLOEXEC(to);
+
+	if (fp->fd == to)	/* impossible? */
+		return;
+
+	(*fp->cb)(fp->fd, to);
+	(void)close(fp->fd);
+	fp->fd = to;
+}
+
+static const struct flgnames {
+	const char *name;
+	uint16_t minch;
+	uint32_t value;
+} nv[] = {
+#ifdef O_APPEND
+	{ "append",	2,	O_APPEND 	},
+#endif
+#ifdef O_ASYNC
+	{ "async",	2,	O_ASYNC		},
+#endif
+#ifdef O_SYNC
+	{ "sync",	2,	O_SYNC		},
+#endif
+#ifdef O_NONBLOCK
+	{ "nonblock",	3,	O_NONBLOCK	},
+#endif
+#ifdef O_FSYNC
+	{ "fsync",	2,	O_FSYNC		},
+#endif
+#ifdef O_DSYNC
+	{ "dsync",	2,	O_DSYNC		},
+#endif
+#ifdef O_RSYNC
+	{ "rsync",	2,	O_RSYNC		},
+#endif
+#ifdef O_ALT_IO
+	{ "altio",	2,	O_ALT_IO	},
+#endif
+#ifdef O_DIRECT
+	{ "direct",	2,	O_DIRECT	},
+#endif
+#ifdef O_NOSIGPIPE
+	{ "nosigpipe",	3,	O_NOSIGPIPE	},
+#endif
+#ifdef O_CLOEXEC
+	{ "cloexec",	2,	O_CLOEXEC	},
+#endif
+	{ 0, 0, 0 }
+};
+#define ALLFLAGS (O_APPEND|O_ASYNC|O_SYNC|O_NONBLOCK|O_DSYNC|O_RSYNC|\
+    O_ALT_IO|O_DIRECT|O_NOSIGPIPE|O_CLOEXEC)
+
+static int
+getflags(int fd, int p)
+{
+	int c, f;
+
+	if (sh_fd(fd) != NULL) {
+		if (!p)
+			return -1;
+		error("Can't get status for fd=%d (%s)", fd,
+		    "Bad file descriptor");			/*XXX*/
+	}
+
+	if ((c = fcntl(fd, F_GETFD)) == -1) {
+		if (!p)
+			return -1;
+		error("Can't get status for fd=%d (%s)", fd, strerror(errno));
+	}
+	if ((f = fcntl(fd, F_GETFL)) == -1) {
+		if (!p)
+			return -1;
+		error("Can't get flags for fd=%d (%s)", fd, strerror(errno));
+	}
+	if (c & FD_CLOEXEC)
+		f |= O_CLOEXEC;
+	return f & ALLFLAGS;
+}
+
+static void
+printone(int fd, int p, int verbose, int pfd)
+{
+	int f = getflags(fd, p);
+	const struct flgnames *fn;
+
+	if (f == -1)
+		return;
+
+	if (pfd)
+		outfmt(out1, "%d: ", fd);
+	for (fn = nv; fn->name; fn++) {
+		if (f & fn->value) {
+			outfmt(out1, "%s%s", verbose ? "+" : "", fn->name);
+			f &= ~fn->value;
+		} else if (verbose)
+			outfmt(out1, "-%s", fn->name);
+		else
+			continue;
+		if (f || (verbose && fn[1].name))
+			outfmt(out1, ",");
+	}
+	if (verbose && f)		/* f should be normally be 0 */
+		outfmt(out1, " +%#x", f);
+	outfmt(out1, "\n");
+}
+
+static void
+parseflags(char *s, int *p, int *n)
+{
+	int *v, *w;
+	const struct flgnames *fn;
+	size_t len;
+
+	*p = 0;
+	*n = 0;
+	for (s = strtok(s, ","); s; s = strtok(NULL, ",")) {
+		switch (*s++) {
+		case '+':
+			v = p;
+			w = n;
+			break;
+		case '-':
+			v = n;
+			w = p;
+			break;
+		default:
+			error("Missing +/- indicator before flag %s", s-1);
+		}
+
+		len = strlen(s);
+		for (fn = nv; fn->name; fn++)
+			if (len >= fn->minch && strncmp(s,fn->name,len) == 0) {
+				*v |= fn->value;
+				*w &=~ fn->value;
+				break;
+			}
+		if (fn->name == 0)
+			error("Bad flag `%s'", s);
+	}
+}
+
+static void
+setone(int fd, int pos, int neg, int verbose)
+{
+	int f = getflags(fd, 1);
+	int n, cloexec;
+
+	if (f == -1)
+		return;
+
+	cloexec = -1;
+	if ((pos & O_CLOEXEC) && !(f & O_CLOEXEC))
+		cloexec = FD_CLOEXEC;
+	if ((neg & O_CLOEXEC) && (f & O_CLOEXEC))
+		cloexec = 0;
+
+	if (cloexec != -1 && fcntl(fd, F_SETFD, cloexec) == -1)
+		error("Can't set status for fd=%d (%s)", fd, strerror(errno));
+
+	pos &= ~O_CLOEXEC;
+	neg &= ~O_CLOEXEC;
+	f &= ~O_CLOEXEC;
+	n = f;
+	n |= pos;
+	n &= ~neg;
+	if (n != f && fcntl(fd, F_SETFL, n) == -1)
+		error("Can't set flags for fd=%d (%s)", fd, strerror(errno));
+	if (verbose)
+		printone(fd, 1, verbose, 1);
+}
+
+int
+fdflagscmd(int argc, char *argv[])
+{
+	char *num;
+	int verbose = 0, ch, pos = 0, neg = 0;
+	char *setflags = NULL;
+
+	optreset = 1; optind = 1; /* initialize getopt */
+	while ((ch = getopt(argc, argv, ":vs:")) != -1)
+		switch ((char)ch) {
+		case 'v':
+			verbose = 1;
+			break;
+		case 's':
+			if (setflags)
+				goto msg;
+			setflags = optarg;
+			break;
+		case '?':
+		default:
+		msg:
+			error("Usage: fdflags [-v] [-s <flags> fd] [fd...]");
+			/* NOTREACHED */
+		}
+
+	argc -= optind, argv += optind;
+
+	if (setflags)
+		parseflags(setflags, &pos, &neg);
+
+	if (argc == 0) {
+		int i;
+
+		if (setflags)
+			goto msg;
+
+		for (i = 0; i <= max_user_fd; i++)
+			printone(i, 0, verbose, 1);
+		return 0;
+	}
+
+	while ((num = *argv++) != NULL) {
+		int fd = number(num);
+
+		while (num[0] == '0' && num[1] != '\0')		/* skip 0's */
+			num++;
+		if (strlen(num) > 5)
+			error("%s too big to be a file descriptor", num);
+
+		if (setflags)
+			setone(fd, pos, neg, verbose);
+		else
+			printone(fd, 1, verbose, argc > 1);
+	}
+	return 0;
+}
+
+#undef MAX		/* in case we inherited them from somewhere */
+#undef MIN
+
+#define	MIN(a,b)	(/*CONSTCOND*/((a)<=(b)) ? (a) : (b))
+#define	MAX(a,b)	(/*CONSTCOND*/((a)>=(b)) ? (a) : (b))
+
+		/* now make the compiler work for us... */
+#define	MIN_REDIR	MIN(MIN(MIN(MIN(NTO,NFROM), MIN(NTOFD,NFROMFD)), \
+		   MIN(MIN(NCLOBBER,NAPPEND), MIN(NHERE,NXHERE))), NFROMTO)
+#define	MAX_REDIR	MAX(MAX(MAX(MAX(NTO,NFROM), MAX(NTOFD,NFROMFD)), \
+		   MAX(MAX(NCLOBBER,NAPPEND), MAX(NHERE,NXHERE))), NFROMTO)
+
+static const char *redir_sym[MAX_REDIR - MIN_REDIR + 1] = {
+	[NTO      - MIN_REDIR]=	">",
+	[NFROM    - MIN_REDIR]=	"<",
+	[NTOFD    - MIN_REDIR]=	">&",
+	[NFROMFD  - MIN_REDIR]=	"<&",
+	[NCLOBBER - MIN_REDIR]=	">|",
+	[NAPPEND  - MIN_REDIR]=	">>",
+	[NHERE    - MIN_REDIR]=	"<<",
+	[NXHERE   - MIN_REDIR]=	"<<",
+	[NFROMTO  - MIN_REDIR]=	"<>",
+};
+
+int
+outredir(struct output *out, union node *n, int sep)
+{
+	if (n == NULL)
+		return 0;
+	if (n->type < MIN_REDIR || n->type > MAX_REDIR ||
+	    redir_sym[n->type - MIN_REDIR] == NULL)
+		return 0;
+
+	if (sep)
+		outc(sep, out);
+
+	/*
+	 * ugly, but all redir node types have "fd" in same slot...
+	 *	(and code other places assumes it as well)
+	 */
+	if ((redir_sym[n->type - MIN_REDIR][0] == '<' && n->nfile.fd != 0) ||
+	    (redir_sym[n->type - MIN_REDIR][0] == '>' && n->nfile.fd != 1))
+		outfmt(out, "%d", n->nfile.fd);
+
+	outstr(redir_sym[n->type - MIN_REDIR], out);
+
+	switch (n->type) {
+	case NHERE:
+		outstr("'...'", out);
+		break;
+	case NXHERE:
+		outstr("...", out);
+		break;
+	case NTOFD:
+	case NFROMFD:
+		if (n->ndup.dupfd < 0)
+			outc('-', out);
+		else
+			outfmt(out, "%d", n->ndup.dupfd);
+		break;
+	default:
+		outstr(n->nfile.expfname, out);
+		break;
+	}
+	return 1;
+}