usr/dash/redir.c

/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1997-2005
 *	Herbert Xu <herbert@gondor.apana.org.au>.  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/stat.h>
#include <sys/types.h>
#include <sys/param.h>	/* PIPE_BUF */
#include <signal.h>
#include <string.h>
#include <fcntl.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 REALLY_CLOSED -3	/* fd that was closed and still is */
#define EMPTY -2		/* marks an unused slot in redirtab */
#define CLOSED -1		/* fd opened for redir needs to be closed */

#ifndef PIPE_BUF
# define PIPESIZE 4096		/* amount of buffering in a pipe */
#else
# define PIPESIZE PIPE_BUF
#endif


MKINIT
struct redirtab {
	struct redirtab *next;
	int renamed[10];
	int nullredirs;
};


MKINIT struct redirtab *redirlist;
MKINIT int nullredirs;

STATIC int openredirect(union node *);
#ifdef notyet
STATIC void dupredirect(union node *, int, char[10]);
#else
STATIC void dupredirect(union node *, int);
#endif
STATIC int openhere(union node *);
STATIC int noclobberopen(const char *);


/*
 * 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;
	int i;
	int fd;
	int newfd;
	int *p;
#if notyet
	char memory[10];	/* file descriptors to write to memory */

	for (i = 10 ; --i >= 0 ; )
		memory[i] = 0;
	memory[1] = flags & REDIR_BACKQ;
#endif
	nullredirs++;
	if (!redir) {
		return;
	}
	sv = NULL;
	INTOFF;
	if (likely(flags & REDIR_PUSH)) {
		struct redirtab *q;
		q = ckmalloc(sizeof (struct redirtab));
		q->next = redirlist;
		redirlist = q;
		q->nullredirs = nullredirs - 1;
		for (i = 0 ; i < 10 ; i++)
			q->renamed[i] = EMPTY;
		nullredirs = 0;
		sv = q;
	}
	n = redir;
	do {
		newfd = openredirect(n);
		if (newfd < -1)
			continue;

		fd = n->nfile.fd;

		if (sv) {
			p = &sv->renamed[fd];
			i = *p;

			if (likely(i == EMPTY)) {
				i = CLOSED;
				if (fd != newfd) {
					i = savefd(fd, fd);
					fd = -1;
				}
			}

			if (i == newfd)
				/* Can only happen if i == newfd == CLOSED */
				i = REALLY_CLOSED;

			*p = i;
		}

		if (fd == newfd)
			continue;

#ifdef notyet
		dupredirect(n, newfd, memory);
#else
		dupredirect(n, newfd);
#endif
	} while ((n = n->nfile.next));
	INTON;
#ifdef notyet
	if (memory[1])
		out1 = &memout;
	if (memory[2])
		out2 = &memout;
#endif
	if (flags & REDIR_SAVEFD2 && sv->renamed[2] >= 0)
		preverrout.fd = sv->renamed[2];
}


STATIC int
openredirect(union node *redir)
{
	char *fname;
	int f;

	switch (redir->nfile.type) {
	case NFROM:
		fname = redir->nfile.expfname;
		if ((f = open64(fname, O_RDONLY)) < 0)
			goto eopen;
		break;
	case NFROMTO:
		fname = redir->nfile.expfname;
		if ((f = open64(fname, O_RDWR|O_CREAT, 0666)) < 0)
			goto ecreate;
		break;
	case NTO:
		/* Take care of noclobber mode. */
		if (Cflag) {
			fname = redir->nfile.expfname;
			if ((f = noclobberopen(fname)) < 0)
				goto ecreate;
			break;
		}
		/* FALLTHROUGH */
	case NCLOBBER:
		fname = redir->nfile.expfname;
		if ((f = open64(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
			goto ecreate;
		break;
	case NAPPEND:
		fname = redir->nfile.expfname;
		if ((f = open64(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
			goto ecreate;
		break;
	case NTOFD:
	case NFROMFD:
		f = redir->ndup.dupfd;
		if (f == redir->nfile.fd)
			f = -2;
		break;
	default:
#ifdef DEBUG
		abort();
#endif
		/* Fall through to eliminate warning. */
	case NHERE:
	case NXHERE:
		f = openhere(redir);
		break;
	}

	return f;
ecreate:
	sh_error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
eopen:
	sh_error("cannot open %s: %s", fname, errmsg(errno, E_OPEN));
}


STATIC void
#ifdef notyet
dupredirect(redir, f, memory)
#else
dupredirect(redir, f)
#endif
	union node *redir;
	int f;
#ifdef notyet
	char memory[10];
#endif
	{
	int fd = redir->nfile.fd;
	int err = 0;

#ifdef notyet
	memory[fd] = 0;
#endif
	if (redir->nfile.type == NTOFD || redir->nfile.type == NFROMFD) {
		/* if not ">&-" */
		if (f >= 0) {
#ifdef notyet
			if (memory[f])
				memory[fd] = 1;
			else
#endif
				if (dup2(f, fd) < 0) {
					err = errno;
					goto err;
				}
			return;
		}
		f = fd;
	} else if (dup2(f, fd) < 0)
		err = errno;

	close(f);
	if (err < 0)
		goto err;

	return;

err:
	sh_error("%d: %s", f, strerror(err));
}


/*
 * 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)
{
	char *p;
	int pip[2];
	size_t len = 0;

	if (pipe(pip) < 0)
		sh_error("Pipe call failed");

	p = redir->nhere.doc->narg.text;
	if (redir->type == NXHERE) {
		expandarg(redir->nhere.doc, NULL, EXP_QUOTED);
		p = stackblock();
	}

	len = strlen(p);
	if (len <= PIPESIZE) {
		xwrite(pip[1], p, 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);
		xwrite(pip[1], p, len);
		_exit(0);
	}
out:
	close(pip[1]);
	return pip[0];
}


/*
 * Undo the effects of the last redirection.
 */

void
popredir(int drop)
{
	struct redirtab *rp;
	int i;

	if (--nullredirs >= 0)
		return;
	INTOFF;
	rp = redirlist;
	for (i = 0 ; i < 10 ; i++) {
		switch (rp->renamed[i]) {
		case CLOSED:
			if (!drop)
				close(i);
			break;
		case EMPTY:
		case REALLY_CLOSED:
			break;
		default:
			if (!drop)
				dup2(rp->renamed[i], i);
			close(rp->renamed[i]);
			break;
		}
	}
	redirlist = rp->next;
	nullredirs = rp->nullredirs;
	ckfree(rp);
	INTON;
}

/*
 * Undo all redirections.  Called on error or interrupt.
 */

#ifdef mkinit

INCLUDE "redir.h"

RESET {
	/*
	 * Discard all saved file descriptors.
	 */
	for (;;) {
		nullredirs = 0;
		if (!redirlist)
			break;
		popredir(0);
	}
}

#endif


/*
 * Move a file descriptor to > 10.  Invokes sh_error on error unless
 * the original file dscriptor is not open.
 */

int
savefd(int from, int ofd)
{
	int newfd;
	int err;

	newfd = fcntl(from, F_DUPFD, 10);
	err = newfd < 0 ? errno : 0;
	if (err != EBADF) {
		close(ofd);
		if (err)
			sh_error("%d: %s", from, strerror(err));
		else
			fcntl(newfd, F_SETFD, FD_CLOEXEC);
	}

	return newfd;
}


/*
 * Open a file in noclobber mode.
 * The code was copied from bash.
 */
int
noclobberopen(fname)
	const char *fname;
{
	int r, fd;
	struct stat64 finfo, finfo2;

	/*
	 * If the file exists and is a regular file, return an error
	 * immediately.
	 */
	r = stat64(fname, &finfo);
	if (r == 0 && S_ISREG(finfo.st_mode)) {
		errno = EEXIST;
		return -1;
	}

	/*
	 * If the file was not present (r != 0), make sure we open it
	 * exclusively so that if it is created before we open it, our open
	 * will fail.  Make sure that we do not truncate an existing file.
	 * Note that we don't turn on O_EXCL unless the stat failed -- if the
	 * file was not a regular file, we leave O_EXCL off.
	 */
	if (r != 0)
		return open64(fname, O_WRONLY|O_CREAT|O_EXCL, 0666);
	fd = open64(fname, O_WRONLY|O_CREAT, 0666);

	/* If the open failed, return the file descriptor right away. */
	if (fd < 0)
		return fd;

	/*
	 * OK, the open succeeded, but the file may have been changed from a
	 * non-regular file to a regular file between the stat and the open.
	 * We are assuming that the O_EXCL open handles the case where FILENAME
	 * did not exist and is symlinked to an existing file between the stat
	 * and open.
	 */

	/*
	 * If we can open it and fstat the file descriptor, and neither check
	 * revealed that it was a regular file, and the file has not been
	 * replaced, return the file descriptor.
	 */
	 if (fstat64(fd, &finfo2) == 0 && !S_ISREG(finfo2.st_mode) &&
	     finfo.st_dev == finfo2.st_dev && finfo.st_ino == finfo2.st_ino)
	 	return fd;

	/* The file has been replaced.  badness. */
	close(fd);
	errno = EEXIST;
	return -1;
}


int
redirectsafe(union node *redir, int flags)
{
	int err;
	volatile int saveint;
	struct jmploc *volatile savehandler = handler;
	struct jmploc jmploc;

	SAVEINT(saveint);
	if (!(err = setjmp(jmploc.loc) * 2)) {
		handler = &jmploc;
		redirect(redir, flags);
	}
	handler = savehandler;
	if (err && exception != EXERROR)
		longjmp(handler->loc, 1);
	RESTOREINT(saveint);
	return err;
}
1	niro	532	/*-
2			* Copyright (c) 1991, 1993
3			* The Regents of the University of California. All rights reserved.
4			* Copyright (c) 1997-2005
5			* Herbert Xu <herbert@gondor.apana.org.au>. All rights reserved.
6			*
7			* This code is derived from software contributed to Berkeley by
8			* Kenneth Almquist.
9			*
10			* Redistribution and use in source and binary forms, with or without
11			* modification, are permitted provided that the following conditions
12			* are met:
13			* 1. Redistributions of source code must retain the above copyright
14			* notice, this list of conditions and the following disclaimer.
15			* 2. Redistributions in binary form must reproduce the above copyright
16			* notice, this list of conditions and the following disclaimer in the
17			* documentation and/or other materials provided with the distribution.
18			* 3. Neither the name of the University nor the names of its contributors
19			* may be used to endorse or promote products derived from this software
20			* without specific prior written permission.
21			*
22			* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25			* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32			* SUCH DAMAGE.
33			*/
34
35			#include <sys/stat.h>
36			#include <sys/types.h>
37			#include <sys/param.h> /* PIPE_BUF */
38			#include <signal.h>
39			#include <string.h>
40			#include <fcntl.h>
41			#include <unistd.h>
42			#include <stdlib.h>
43
44			/*
45			* Code for dealing with input/output redirection.
46			*/
47
48			#include "main.h"
49			#include "shell.h"
50			#include "nodes.h"
51			#include "jobs.h"
52			#include "options.h"
53			#include "expand.h"
54			#include "redir.h"
55			#include "output.h"
56			#include "memalloc.h"
57			#include "error.h"
58
59
60	niro	815	#define REALLY_CLOSED -3 /* fd that was closed and still is */
61	niro	532	#define EMPTY -2 /* marks an unused slot in redirtab */
62	niro	815	#define CLOSED -1 /* fd opened for redir needs to be closed */
63
64	niro	532	#ifndef PIPE_BUF
65			# define PIPESIZE 4096 /* amount of buffering in a pipe */
66			#else
67			# define PIPESIZE PIPE_BUF
68			#endif
69
70
71			MKINIT
72			struct redirtab {
73			struct redirtab *next;
74			int renamed[10];
75			int nullredirs;
76			};
77
78
79			MKINIT struct redirtab *redirlist;
80			MKINIT int nullredirs;
81
82			STATIC int openredirect(union node *);
83			#ifdef notyet
84			STATIC void dupredirect(union node *, int, char[10]);
85			#else
86			STATIC void dupredirect(union node *, int);
87			#endif
88			STATIC int openhere(union node *);
89			STATIC int noclobberopen(const char *);
90
91
92			/*
93			* Process a list of redirection commands. If the REDIR_PUSH flag is set,
94			* old file descriptors are stashed away so that the redirection can be
95			* undone by calling popredir. If the REDIR_BACKQ flag is set, then the
96			* standard output, and the standard error if it becomes a duplicate of
97			* stdout, is saved in memory.
98			*/
99
100			void
101			redirect(union node *redir, int flags)
102			{
103			union node *n;
104			struct redirtab *sv;
105			int i;
106			int fd;
107			int newfd;
108			int *p;
109			#if notyet
110			char memory[10]; /* file descriptors to write to memory */
111
112			for (i = 10 ; --i >= 0 ; )
113			memory[i] = 0;
114			memory[1] = flags & REDIR_BACKQ;
115			#endif
116			nullredirs++;
117			if (!redir) {
118			return;
119			}
120			sv = NULL;
121			INTOFF;
122	niro	815	if (likely(flags & REDIR_PUSH)) {
123	niro	532	struct redirtab *q;
124			q = ckmalloc(sizeof (struct redirtab));
125			q->next = redirlist;
126			redirlist = q;
127			q->nullredirs = nullredirs - 1;
128			for (i = 0 ; i < 10 ; i++)
129			q->renamed[i] = EMPTY;
130			nullredirs = 0;
131			sv = q;
132			}
133			n = redir;
134			do {
135	niro	815	newfd = openredirect(n);
136			if (newfd < -1)
137			continue;
138
139	niro	532	fd = n->nfile.fd;
140
141	niro	815	if (sv) {
142			p = &sv->renamed[fd];
143			i = *p;
144
145			if (likely(i == EMPTY)) {
146			i = CLOSED;
147			if (fd != newfd) {
148	niro	1122	i = savefd(fd, fd);
149	niro	815	fd = -1;
150	niro	532	}
151			}
152	niro	815
153			if (i == newfd)
154			/* Can only happen if i == newfd == CLOSED */
155			i = REALLY_CLOSED;
156
157			*p = i;
158	niro	532	}
159	niro	815
160			if (fd == newfd)
161			continue;
162
163	niro	532	#ifdef notyet
164			dupredirect(n, newfd, memory);
165			#else
166			dupredirect(n, newfd);
167			#endif
168			} while ((n = n->nfile.next));
169			INTON;
170			#ifdef notyet
171			if (memory[1])
172			out1 = &memout;
173			if (memory[2])
174			out2 = &memout;
175			#endif
176	niro	815	if (flags & REDIR_SAVEFD2 && sv->renamed[2] >= 0)
177	niro	532	preverrout.fd = sv->renamed[2];
178			}
179
180
181			STATIC int
182			openredirect(union node *redir)
183			{
184			char *fname;
185			int f;
186
187			switch (redir->nfile.type) {
188			case NFROM:
189			fname = redir->nfile.expfname;
190			if ((f = open64(fname, O_RDONLY)) < 0)
191			goto eopen;
192			break;
193			case NFROMTO:
194			fname = redir->nfile.expfname;
195	niro	1122	if ((f = open64(fname, O_RDWR\|O_CREAT, 0666)) < 0)
196	niro	532	goto ecreate;
197			break;
198			case NTO:
199			/* Take care of noclobber mode. */
200			if (Cflag) {
201			fname = redir->nfile.expfname;
202			if ((f = noclobberopen(fname)) < 0)
203			goto ecreate;
204			break;
205			}
206			/* FALLTHROUGH */
207			case NCLOBBER:
208			fname = redir->nfile.expfname;
209			if ((f = open64(fname, O_WRONLY\|O_CREAT\|O_TRUNC, 0666)) < 0)
210			goto ecreate;
211			break;
212			case NAPPEND:
213			fname = redir->nfile.expfname;
214			if ((f = open64(fname, O_WRONLY\|O_CREAT\|O_APPEND, 0666)) < 0)
215			goto ecreate;
216			break;
217	niro	815	case NTOFD:
218			case NFROMFD:
219			f = redir->ndup.dupfd;
220			if (f == redir->nfile.fd)
221			f = -2;
222			break;
223	niro	532	default:
224			#ifdef DEBUG
225			abort();
226			#endif
227			/* Fall through to eliminate warning. */
228			case NHERE:
229			case NXHERE:
230			f = openhere(redir);
231			break;
232			}
233
234			return f;
235			ecreate:
236			sh_error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
237			eopen:
238			sh_error("cannot open %s: %s", fname, errmsg(errno, E_OPEN));
239			}
240
241
242			STATIC void
243			#ifdef notyet
244			dupredirect(redir, f, memory)
245			#else
246			dupredirect(redir, f)
247			#endif
248			union node *redir;
249			int f;
250			#ifdef notyet
251			char memory[10];
252			#endif
253			{
254			int fd = redir->nfile.fd;
255	niro	815	int err = 0;
256	niro	532
257			#ifdef notyet
258			memory[fd] = 0;
259			#endif
260			if (redir->nfile.type == NTOFD \|\| redir->nfile.type == NFROMFD) {
261	niro	815	/* if not ">&-" */
262			if (f >= 0) {
263	niro	532	#ifdef notyet
264	niro	815	if (memory[f])
265	niro	532	memory[fd] = 1;
266			else
267			#endif
268	niro	815	if (dup2(f, fd) < 0) {
269			err = errno;
270			goto err;
271			}
272			return;
273	niro	532	}
274	niro	815	f = fd;
275			} else if (dup2(f, fd) < 0)
276			err = errno;
277	niro	532
278	niro	815	close(f);
279			if (err < 0)
280			goto err;
281
282	niro	532	return;
283	niro	815
284			err:
285			sh_error("%d: %s", f, strerror(err));
286	niro	532	}
287
288
289			/*
290			* Handle here documents. Normally we fork off a process to write the
291			* data to a pipe. If the document is short, we can stuff the data in
292			* the pipe without forking.
293			*/
294
295			STATIC int
296			openhere(union node *redir)
297			{
298	niro	1122	char *p;
299	niro	532	int pip[2];
300			size_t len = 0;
301
302			if (pipe(pip) < 0)
303			sh_error("Pipe call failed");
304	niro	1122
305			p = redir->nhere.doc->narg.text;
306			if (redir->type == NXHERE) {
307			expandarg(redir->nhere.doc, NULL, EXP_QUOTED);
308			p = stackblock();
309	niro	532	}
310	niro	1122
311			len = strlen(p);
312			if (len <= PIPESIZE) {
313			xwrite(pip[1], p, len);
314			goto out;
315			}
316
317	niro	532	if (forkshell((struct job )NULL, (union node )NULL, FORK_NOJOB) == 0) {
318			close(pip[0]);
319			signal(SIGINT, SIG_IGN);
320			signal(SIGQUIT, SIG_IGN);
321			signal(SIGHUP, SIG_IGN);
322			#ifdef SIGTSTP
323			signal(SIGTSTP, SIG_IGN);
324			#endif
325			signal(SIGPIPE, SIG_DFL);
326	niro	1122	xwrite(pip[1], p, len);
327	niro	532	_exit(0);
328			}
329			out:
330			close(pip[1]);
331			return pip[0];
332			}
333
334
335
336			/*
337			* Undo the effects of the last redirection.
338			*/
339
340			void
341			popredir(int drop)
342			{
343			struct redirtab *rp;
344			int i;
345
346			if (--nullredirs >= 0)
347			return;
348			INTOFF;
349			rp = redirlist;
350			for (i = 0 ; i < 10 ; i++) {
351	niro	815	switch (rp->renamed[i]) {
352			case CLOSED:
353			if (!drop)
354	niro	532	close(i);
355	niro	815	break;
356			case EMPTY:
357			case REALLY_CLOSED:
358			break;
359			default:
360			if (!drop)
361			dup2(rp->renamed[i], i);
362	niro	532	close(rp->renamed[i]);
363	niro	815	break;
364	niro	532	}
365			}
366			redirlist = rp->next;
367			nullredirs = rp->nullredirs;
368			ckfree(rp);
369			INTON;
370			}
371
372			/*
373			* Undo all redirections. Called on error or interrupt.
374			*/
375
376			#ifdef mkinit
377
378			INCLUDE "redir.h"
379
380			RESET {
381	niro	815	/*
382			* Discard all saved file descriptors.
383			*/
384	niro	532	for (;;) {
385			nullredirs = 0;
386			if (!redirlist)
387			break;
388	niro	815	popredir(0);
389	niro	532	}
390			}
391
392	niro	815	#endif
393	niro	532
394
395	niro	815
396	niro	532	/*
397	niro	815	* Move a file descriptor to > 10. Invokes sh_error on error unless
398			* the original file dscriptor is not open.
399	niro	532	*/
400
401			int
402	niro	1122	savefd(int from, int ofd)
403	niro	532	{
404			int newfd;
405	niro	815	int err;
406	niro	532
407	niro	815	newfd = fcntl(from, F_DUPFD, 10);
408			err = newfd < 0 ? errno : 0;
409			if (err != EBADF) {
410	niro	1122	close(ofd);
411	niro	815	if (err)
412			sh_error("%d: %s", from, strerror(err));
413	niro	532	else
414	niro	815	fcntl(newfd, F_SETFD, FD_CLOEXEC);
415	niro	532	}
416	niro	815
417	niro	532	return newfd;
418			}
419
420
421			/*
422			* Open a file in noclobber mode.
423			* The code was copied from bash.
424			*/
425			int
426			noclobberopen(fname)
427			const char *fname;
428			{
429			int r, fd;
430			struct stat64 finfo, finfo2;
431
432			/*
433			* If the file exists and is a regular file, return an error
434			* immediately.
435			*/
436			r = stat64(fname, &finfo);
437			if (r == 0 && S_ISREG(finfo.st_mode)) {
438			errno = EEXIST;
439			return -1;
440			}
441
442			/*
443			* If the file was not present (r != 0), make sure we open it
444			* exclusively so that if it is created before we open it, our open
445			* will fail. Make sure that we do not truncate an existing file.
446			* Note that we don't turn on O_EXCL unless the stat failed -- if the
447			* file was not a regular file, we leave O_EXCL off.
448			*/
449			if (r != 0)
450			return open64(fname, O_WRONLY\|O_CREAT\|O_EXCL, 0666);
451			fd = open64(fname, O_WRONLY\|O_CREAT, 0666);
452
453			/* If the open failed, return the file descriptor right away. */
454			if (fd < 0)
455			return fd;
456
457			/*
458			* OK, the open succeeded, but the file may have been changed from a
459			* non-regular file to a regular file between the stat and the open.
460			* We are assuming that the O_EXCL open handles the case where FILENAME
461			* did not exist and is symlinked to an existing file between the stat
462			* and open.
463			*/
464
465			/*
466			* If we can open it and fstat the file descriptor, and neither check
467			* revealed that it was a regular file, and the file has not been
468			* replaced, return the file descriptor.
469			*/
470			if (fstat64(fd, &finfo2) == 0 && !S_ISREG(finfo2.st_mode) &&
471			finfo.st_dev == finfo2.st_dev && finfo.st_ino == finfo2.st_ino)
472			return fd;
473
474			/* The file has been replaced. badness. */
475			close(fd);
476			errno = EEXIST;
477			return -1;
478			}
479
480
481			int
482			redirectsafe(union node *redir, int flags)
483			{
484			int err;
485			volatile int saveint;
486			struct jmploc *volatile savehandler = handler;
487			struct jmploc jmploc;
488
489			SAVEINT(saveint);
490			if (!(err = setjmp(jmploc.loc) * 2)) {
491			handler = &jmploc;
492			redirect(redir, flags);
493			}
494			handler = savehandler;
495			if (err && exception != EXERROR)
496			longjmp(handler->loc, 1);
497			RESTOREINT(saveint);
498			return err;
499			}