/* $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;
}