sh/redir.c - android_system_core - Gitiles

 /*	$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;
 }
	/* $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;
	}