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[dragonfly.git] / bin / sh / redir.c
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1/*-
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
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35 *
36 * @(#)redir.c 8.2 (Berkeley) 5/4/95
37 * $FreeBSD: src/bin/sh/redir.c,v 1.12.2.4 2002/08/27 01:36:28 tjr Exp $
f8903466 38 * $DragonFly: src/bin/sh/redir.c,v 1.3 2003/08/24 16:26:00 drhodus Exp $
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39 */
40
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41#include <sys/types.h>
42#include <sys/stat.h>
43#include <signal.h>
44#include <string.h>
45#include <fcntl.h>
46#include <errno.h>
47#include <unistd.h>
48#include <stdlib.h>
49
50/*
51 * Code for dealing with input/output redirection.
52 */
53
54#include "shell.h"
55#include "nodes.h"
56#include "jobs.h"
57#include "expand.h"
58#include "redir.h"
59#include "output.h"
60#include "memalloc.h"
61#include "error.h"
62#include "options.h"
63
64
65#define EMPTY -2 /* marks an unused slot in redirtab */
66#define PIPESIZE 4096 /* amount of buffering in a pipe */
67
68
69MKINIT
70struct redirtab {
71 struct redirtab *next;
72 int renamed[10];
73};
74
75
76MKINIT struct redirtab *redirlist;
77
78/*
79 * We keep track of whether or not fd0 has been redirected. This is for
80 * background commands, where we want to redirect fd0 to /dev/null only
81 * if it hasn't already been redirected.
82*/
f8903466 83STATIC int fd0_redirected = 0;
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84
85STATIC void openredirect(union node *, char[10 ]);
86STATIC int openhere(union node *);
87
88
89/*
90 * Process a list of redirection commands. If the REDIR_PUSH flag is set,
91 * old file descriptors are stashed away so that the redirection can be
92 * undone by calling popredir. If the REDIR_BACKQ flag is set, then the
93 * standard output, and the standard error if it becomes a duplicate of
94 * stdout, is saved in memory.
95 */
96
97void
98redirect(union node *redir, int flags)
99{
100 union node *n;
101 struct redirtab *sv = NULL;
102 int i;
103 int fd;
104 int try;
105 char memory[10]; /* file descriptors to write to memory */
106
107 for (i = 10 ; --i >= 0 ; )
108 memory[i] = 0;
109 memory[1] = flags & REDIR_BACKQ;
110 if (flags & REDIR_PUSH) {
111 sv = ckmalloc(sizeof (struct redirtab));
112 for (i = 0 ; i < 10 ; i++)
113 sv->renamed[i] = EMPTY;
114 sv->next = redirlist;
115 redirlist = sv;
116 }
117 for (n = redir ; n ; n = n->nfile.next) {
118 fd = n->nfile.fd;
119 try = 0;
120 if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
121 n->ndup.dupfd == fd)
122 continue; /* redirect from/to same file descriptor */
123
124 if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
125 INTOFF;
126again:
127 if ((i = fcntl(fd, F_DUPFD, 10)) == -1) {
128 switch (errno) {
129 case EBADF:
130 if (!try) {
131 openredirect(n, memory);
132 try++;
133 goto again;
134 }
135 /* FALLTHROUGH*/
136 default:
137 INTON;
138 error("%d: %s", fd, strerror(errno));
139 break;
140 }
141 }
142 if (!try) {
143 sv->renamed[fd] = i;
144 }
145 INTON;
146 }
147 if (fd == 0)
148 fd0_redirected++;
149 if (!try)
150 openredirect(n, memory);
151 }
152 if (memory[1])
153 out1 = &memout;
154 if (memory[2])
155 out2 = &memout;
156}
157
158
159STATIC void
160openredirect(union node *redir, char memory[10])
161{
162 struct stat sb;
163 int fd = redir->nfile.fd;
164 char *fname;
165 int f;
166
167 /*
168 * We suppress interrupts so that we won't leave open file
169 * descriptors around. This may not be such a good idea because
170 * an open of a device or a fifo can block indefinitely.
171 */
172 INTOFF;
173 memory[fd] = 0;
174 switch (redir->nfile.type) {
175 case NFROM:
176 fname = redir->nfile.expfname;
177 if ((f = open(fname, O_RDONLY)) < 0)
178 error("cannot open %s: %s", fname, errmsg(errno, E_OPEN));
179movefd:
180 if (f != fd) {
181 close(fd);
182 copyfd(f, fd);
183 close(f);
184 }
185 break;
186 case NFROMTO:
187 fname = redir->nfile.expfname;
188#ifdef O_CREAT
189 if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0)
190 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
191#else
192 if ((f = open(fname, O_RDWR, 0666)) < 0) {
193 if (errno != ENOENT)
194 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
195 else if ((f = creat(fname, 0666)) < 0)
196 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
197 else {
198 close(f);
199 if ((f = open(fname, O_RDWR)) < 0) {
200 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
201 remove(fname);
202 }
203 }
204 }
205#endif
206 goto movefd;
207 case NTO:
208 fname = redir->nfile.expfname;
209 if (Cflag && stat(fname, &sb) != -1 && S_ISREG(sb.st_mode))
210 error("cannot create %s: %s", fname,
211 errmsg(EEXIST, E_CREAT));
212#ifdef O_CREAT
213 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
214 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
215#else
216 if ((f = creat(fname, 0666)) < 0)
217 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
218#endif
219 goto movefd;
220 case NCLOBBER:
221 fname = redir->nfile.expfname;
222 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
223 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
224 goto movefd;
225 case NAPPEND:
226 fname = redir->nfile.expfname;
227#ifdef O_APPEND
228 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
229 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
230#else
231 if ((f = open(fname, O_WRONLY)) < 0
232 && (f = creat(fname, 0666)) < 0)
233 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
234 lseek(f, (off_t)0, 2);
235#endif
236 goto movefd;
237 case NTOFD:
238 case NFROMFD:
239 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
240 if (memory[redir->ndup.dupfd])
241 memory[fd] = 1;
242 else {
243 close(fd);
244 copyfd(redir->ndup.dupfd, fd);
245 }
246 } else
247 close(fd);
248 break;
249 case NHERE:
250 case NXHERE:
251 f = openhere(redir);
252 goto movefd;
253 default:
254 abort();
255 }
256 INTON;
257}
258
259
260/*
261 * Handle here documents. Normally we fork off a process to write the
262 * data to a pipe. If the document is short, we can stuff the data in
263 * the pipe without forking.
264 */
265
266STATIC int
267openhere(union node *redir)
268{
269 int pip[2];
270 int len = 0;
271
272 if (pipe(pip) < 0)
273 error("Pipe call failed: %s", strerror(errno));
274 if (redir->type == NHERE) {
275 len = strlen(redir->nhere.doc->narg.text);
276 if (len <= PIPESIZE) {
277 xwrite(pip[1], redir->nhere.doc->narg.text, len);
278 goto out;
279 }
280 }
281 if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
282 close(pip[0]);
283 signal(SIGINT, SIG_IGN);
284 signal(SIGQUIT, SIG_IGN);
285 signal(SIGHUP, SIG_IGN);
286#ifdef SIGTSTP
287 signal(SIGTSTP, SIG_IGN);
288#endif
289 signal(SIGPIPE, SIG_DFL);
290 if (redir->type == NHERE)
291 xwrite(pip[1], redir->nhere.doc->narg.text, len);
292 else
293 expandhere(redir->nhere.doc, pip[1]);
294 _exit(0);
295 }
296out:
297 close(pip[1]);
298 return pip[0];
299}
300
301
302
303/*
304 * Undo the effects of the last redirection.
305 */
306
307void
308popredir(void)
309{
310 struct redirtab *rp = redirlist;
311 int i;
312
313 for (i = 0 ; i < 10 ; i++) {
314 if (rp->renamed[i] != EMPTY) {
315 if (i == 0)
316 fd0_redirected--;
317 close(i);
318 if (rp->renamed[i] >= 0) {
319 copyfd(rp->renamed[i], i);
320 close(rp->renamed[i]);
321 }
322 }
323 }
324 INTOFF;
325 redirlist = rp->next;
326 ckfree(rp);
327 INTON;
328}
329
330/*
331 * Undo all redirections. Called on error or interrupt.
332 */
333
334#ifdef mkinit
335
336INCLUDE "redir.h"
337
338RESET {
339 while (redirlist)
340 popredir();
341}
342
343SHELLPROC {
344 clearredir();
345}
346
347#endif
348
349/* Return true if fd 0 has already been redirected at least once. */
350int
351fd0_redirected_p(void)
352{
353 return fd0_redirected != 0;
354}
355
356/*
357 * Discard all saved file descriptors.
358 */
359
360void
361clearredir(void)
362{
363 struct redirtab *rp;
364 int i;
365
366 for (rp = redirlist ; rp ; rp = rp->next) {
367 for (i = 0 ; i < 10 ; i++) {
368 if (rp->renamed[i] >= 0) {
369 close(rp->renamed[i]);
370 }
371 rp->renamed[i] = EMPTY;
372 }
373 }
374}
375
376
377
378/*
379 * Copy a file descriptor to be >= to. Returns -1
380 * if the source file descriptor is closed, EMPTY if there are no unused
381 * file descriptors left.
382 */
383
384int
385copyfd(int from, int to)
386{
387 int newfd;
388
389 newfd = fcntl(from, F_DUPFD, to);
390 if (newfd < 0) {
391 if (errno == EMFILE)
392 return EMPTY;
393 else
394 error("%d: %s", from, strerror(errno));
395 }
396 return newfd;
397}