BSD 4.4 Lite bin Sources

1 files changed, 343 insertions, 0 deletions

diff --git a/bin/sh/redir.c b/bin/sh/redir.c
new file mode 100644
index 0000000..b91ce5a
--- /dev/null
+++ b/bin/sh/redir.c
@@ -0,0 +1,343 @@
+/*-
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. 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
+static char sccsid[] = "@(#)redir.c	8.1 (Berkeley) 5/31/93";
+#endif /* not lint */
+
+/*
+ * 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 <sys/types.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+
+
+#define EMPTY -2		/* marks an unused slot in redirtab */
+#define PIPESIZE 4096		/* amount of buffering in a pipe */
+
+
+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;
+
+#ifdef __STDC__
+STATIC void openredirect(union node *, char *);
+STATIC int openhere(union node *);
+#else
+STATIC void openredirect();
+STATIC int openhere();
+#endif
+
+
+
+/*
+ * 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(redir, flags)
+	union node *redir;
+	int flags;
+	{
+	union node *n;
+	struct redirtab *sv;
+	int i;
+	int fd;
+	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) {
+		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;
+		if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
+			INTOFF;
+			if ((i = copyfd(fd, 10)) != EMPTY) {
+				sv->renamed[fd] = i;
+				close(fd);
+			}
+			INTON;
+			if (i == EMPTY)
+				error("Out of file descriptors");
+		} else {
+			close(fd);
+		}
+                if (fd == 0)
+                        fd0_redirected++;
+		openredirect(n, memory);
+	}
+	if (memory[1])
+		out1 = &memout;
+	if (memory[2])
+		out2 = &memout;
+}
+
+
+STATIC void
+openredirect(redir, memory)
+	union node *redir;
+	char memory[10];
+	{
+	int fd = redir->nfile.fd;
+	char *fname;
+	int f;
+
+	/*
+	 * 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 ((f = open(fname, O_RDONLY)) < 0)
+			error("cannot open %s: %s", fname, errmsg(errno, E_OPEN));
+movefd:
+		if (f != fd) {
+			copyfd(f, fd);
+			close(f);
+		}
+		break;
+	case NTO:
+		fname = redir->nfile.expfname;
+#ifdef O_CREAT
+		if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
+			error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
+#else
+		if ((f = creat(fname, 0666)) < 0)
+			error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
+#endif
+		goto movefd;
+	case NAPPEND:
+		fname = redir->nfile.expfname;
+#ifdef O_APPEND
+		if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
+			error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
+#else
+		if ((f = open(fname, O_WRONLY)) < 0
+		 && (f = creat(fname, 0666)) < 0)
+			error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
+		lseek(f, (off_t)0, 2);
+#endif
+		goto movefd;
+	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);
+		}
+		break;
+	case NHERE:
+	case NXHERE:
+		f = openhere(redir);
+		goto movefd;
+	default:
+		abort();
+	}
+	INTON;
+}
+
+
+/*
+ * 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(redir)
+	union node *redir;
+	{
+	int pip[2];
+	int len;
+
+	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() {
+	register 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();
+}
+
+#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() {
+	register 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;
+		}
+	}
+}
+
+
+
+/*
+ * 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(from, to) {
+	int newfd;
+
+	newfd = fcntl(from, F_DUPFD, to);
+	if (newfd < 0 && errno == EMFILE)
+		return EMPTY;
+	return newfd;
+}