freebsd-nq/bin/sh/redir.c
Peter Wemm aa9caaf657 Merge of 4.4-Lite2 sh source, plus some gcc -Wall cleaning. This is a
merge of parallel duplicate work by Steve Price and myself. :-]

There are some changes to the build that are my fault...  mkinit.c was
trying (poorly) to duplicate some of the work that make(1) is designed to
do.  The Makefile hackery is my fault too, the depend list was incomplete
because of some explicit OBJS+= entries, so mkdep wasn't picking up their
source file #includes.

This closes a pile of /bin/sh PR's, but not all of them..

Submitted by: Steve Price <steve@bonsai.hiwaay.net>, peter
1996-09-01 10:22:36 +00:00

351 lines
8.1 KiB
C

/*-
* 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.
*
* $Id: redir.c,v 1.4 1995/10/21 00:47:31 joerg Exp $
*/
#ifndef lint
static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95";
#endif /* not lint */
#include <sys/types.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"
#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;
STATIC void openredirect __P((union node *, char[10 ]));
STATIC int openhere __P((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(redir, flags)
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 */
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 ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
n->ndup.dupfd == fd)
continue; /* redirect from/to myself */
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 = 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() {
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 from;
int to;
{
int newfd;
newfd = fcntl(from, F_DUPFD, to);
if (newfd < 0 && errno == EMFILE)
return EMPTY;
if (newfd < 0)
error("%d: %s", from, strerror(errno));
return newfd;
}