Import /usr/src/bin/sh from FreeBSD 12.1-RELEASE

1 files changed, 365 insertions, 0 deletions

diff --git a/bin/1sh/redir.c b/bin/1sh/redir.c
new file mode 100644
index 00000000..494c88cd
--- /dev/null
+++ b/bin/1sh/redir.c
@@ -0,0 +1,365 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * 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.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)redir.c	8.2 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: releng/12.1/bin/sh/redir.c 326025 2017-11-20 19:49:47Z pfg $");
+
+#include <sys/types.h>
+#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 "shell.h"
+#include "nodes.h"
+#include "jobs.h"
+#include "expand.h"
+#include "redir.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "options.h"
+
+
+#define EMPTY -2		/* marks an unused slot in redirtab */
+#define CLOSED -1		/* fd was not open before redir */
+
+
+struct redirtab {
+	struct redirtab *next;
+	int renamed[10];
+	int fd0_redirected;
+	unsigned int empty_redirs;
+};
+
+
+static 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;
+
+/* Number of redirtabs that have not been allocated. */
+static unsigned int empty_redirs = 0;
+
+static void openredirect(union node *, char[10 ]);
+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.
+*
+ * We suppress interrupts so that we won't leave open file
+ * descriptors around.  Because the signal handler remains
+ * installed and we do not use system call restart, interrupts
+ * will still abort blocking opens such as fifos (they will fail
+ * with EINTR). There is, however, a race condition if an interrupt
+ * arrives after INTOFF and before open blocks.
+ */
+
+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 */
+
+	INTOFF;
+	for (i = 10 ; --i >= 0 ; )
+		memory[i] = 0;
+	memory[1] = flags & REDIR_BACKQ;
+	if (flags & REDIR_PUSH) {
+		empty_redirs++;
+		if (redir != NULL) {
+			sv = ckmalloc(sizeof (struct redirtab));
+			for (i = 0 ; i < 10 ; i++)
+				sv->renamed[i] = EMPTY;
+			sv->fd0_redirected = fd0_redirected;
+			sv->empty_redirs = empty_redirs - 1;
+			sv->next = redirlist;
+			redirlist = sv;
+			empty_redirs = 0;
+		}
+	}
+	for (n = redir ; n ; n = n->nfile.next) {
+		fd = n->nfile.fd;
+		if (fd == 0)
+			fd0_redirected = 1;
+		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;
+			if ((i = fcntl(fd, F_DUPFD_CLOEXEC, 10)) == -1) {
+				switch (errno) {
+				case EBADF:
+					i = CLOSED;
+					break;
+				default:
+					INTON;
+					error("%d: %s", fd, strerror(errno));
+					break;
+				}
+			}
+			sv->renamed[fd] = i;
+			INTON;
+		}
+		openredirect(n, memory);
+		INTON;
+		INTOFF;
+	}
+	if (memory[1])
+		out1 = &memout;
+	if (memory[2])
+		out2 = &memout;
+	INTON;
+}
+
+
+static void
+openredirect(union node *redir, char memory[10])
+{
+	struct stat sb;
+	int fd = redir->nfile.fd;
+	const char *fname;
+	int f;
+	int e;
+
+	memory[fd] = 0;
+	switch (redir->nfile.type) {
+	case NFROM:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_RDONLY)) < 0)
+			error("cannot open %s: %s", fname, strerror(errno));
+		break;
+	case NFROMTO:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0)
+			error("cannot create %s: %s", fname, strerror(errno));
+		break;
+	case NTO:
+		if (Cflag) {
+			fname = redir->nfile.expfname;
+			if (stat(fname, &sb) == -1) {
+				if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0666)) < 0)
+					error("cannot create %s: %s", fname, strerror(errno));
+			} else if (!S_ISREG(sb.st_mode)) {
+				if ((f = open(fname, O_WRONLY, 0666)) < 0)
+					error("cannot create %s: %s", fname, strerror(errno));
+				if (fstat(f, &sb) != -1 && S_ISREG(sb.st_mode)) {
+					close(f);
+					error("cannot create %s: %s", fname,
+					    strerror(EEXIST));
+				}
+			} else
+				error("cannot create %s: %s", fname,
+				    strerror(EEXIST));
+			break;
+		}
+		/* FALLTHROUGH */
+	case NCLOBBER:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
+			error("cannot create %s: %s", fname, strerror(errno));
+		break;
+	case NAPPEND:
+		fname = redir->nfile.expfname;
+		if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
+			error("cannot create %s: %s", fname, strerror(errno));
+		break;
+	case NTOFD:
+	case NFROMFD:
+		if (redir->ndup.dupfd >= 0) {	/* if not ">&-" */
+			if (memory[redir->ndup.dupfd])
+				memory[fd] = 1;
+			else {
+				if (dup2(redir->ndup.dupfd, fd) < 0)
+					error("%d: %s", redir->ndup.dupfd,
+							strerror(errno));
+			}
+		} else {
+			close(fd);
+		}
+		return;
+	case NHERE:
+	case NXHERE:
+		f = openhere(redir);
+		break;
+	default:
+		abort();
+	}
+	if (f != fd) {
+		if (dup2(f, fd) == -1) {
+			e = errno;
+			close(f);
+			error("%d: %s", fd, strerror(e));
+		}
+		close(f);
+	}
+}
+
+
+/*
+ * 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)
+{
+	const char *p;
+	int pip[2];
+	size_t len = 0;
+	int flags;
+	ssize_t written = 0;
+
+	if (pipe(pip) < 0)
+		error("Pipe call failed: %s", strerror(errno));
+
+	if (redir->type == NXHERE)
+		p = redir->nhere.expdoc;
+	else
+		p = redir->nhere.doc->narg.text;
+	len = strlen(p);
+	if (len == 0)
+		goto out;
+	flags = fcntl(pip[1], F_GETFL, 0);
+	if (flags != -1 && fcntl(pip[1], F_SETFL, flags | O_NONBLOCK) != -1) {
+		written = write(pip[1], p, len);
+		if (written < 0)
+			written = 0;
+		if ((size_t)written == len)
+			goto out;
+		fcntl(pip[1], F_SETFL, flags);
+	}
+
+	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);
+		signal(SIGTSTP, SIG_IGN);
+		signal(SIGPIPE, SIG_DFL);
+		xwrite(pip[1], p + written, len - written);
+		_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;
+
+	INTOFF;
+	if (empty_redirs > 0) {
+		empty_redirs--;
+		INTON;
+		return;
+	}
+	for (i = 0 ; i < 10 ; i++) {
+		if (rp->renamed[i] != EMPTY) {
+			if (rp->renamed[i] >= 0) {
+				dup2(rp->renamed[i], i);
+				close(rp->renamed[i]);
+			} else {
+				close(i);
+			}
+		}
+	}
+	fd0_redirected = rp->fd0_redirected;
+	empty_redirs = rp->empty_redirs;
+	redirlist = rp->next;
+	ckfree(rp);
+	INTON;
+}
+
+/* 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(void)
+{
+	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]);
+			}
+			rp->renamed[i] = EMPTY;
+		}
+	}
+}