Initial import from FreeBSD RELENG_4:
[dragonfly.git] / bin / sh / redir.c
CommitLineData
984263bc
MD
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.
35 */
36
37#ifndef lint
38#if 0
39static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95";
40#endif
41#endif /* not lint */
42#include <sys/cdefs.h>
43__FBSDID("$FreeBSD: src/bin/sh/redir.c,v 1.12.2.4 2002/08/27 01:36:28 tjr Exp $");
44
45#include <sys/types.h>
46#include <sys/stat.h>
47#include <signal.h>
48#include <string.h>
49#include <fcntl.h>
50#include <errno.h>
51#include <unistd.h>
52#include <stdlib.h>
53
54/*
55 * Code for dealing with input/output redirection.
56 */
57
58#include "shell.h"
59#include "nodes.h"
60#include "jobs.h"
61#include "expand.h"
62#include "redir.h"
63#include "output.h"
64#include "memalloc.h"
65#include "error.h"
66#include "options.h"
67
68
69#define EMPTY -2 /* marks an unused slot in redirtab */
70#define PIPESIZE 4096 /* amount of buffering in a pipe */
71
72
73MKINIT
74struct redirtab {
75 struct redirtab *next;
76 int renamed[10];
77};
78
79
80MKINIT struct redirtab *redirlist;
81
82/*
83 * We keep track of whether or not fd0 has been redirected. This is for
84 * background commands, where we want to redirect fd0 to /dev/null only
85 * if it hasn't already been redirected.
86*/
87int fd0_redirected = 0;
88
89STATIC void openredirect(union node *, char[10 ]);
90STATIC int openhere(union node *);
91
92
93/*
94 * Process a list of redirection commands. If the REDIR_PUSH flag is set,
95 * old file descriptors are stashed away so that the redirection can be
96 * undone by calling popredir. If the REDIR_BACKQ flag is set, then the
97 * standard output, and the standard error if it becomes a duplicate of
98 * stdout, is saved in memory.
99 */
100
101void
102redirect(union node *redir, int flags)
103{
104 union node *n;
105 struct redirtab *sv = NULL;
106 int i;
107 int fd;
108 int try;
109 char memory[10]; /* file descriptors to write to memory */
110
111 for (i = 10 ; --i >= 0 ; )
112 memory[i] = 0;
113 memory[1] = flags & REDIR_BACKQ;
114 if (flags & REDIR_PUSH) {
115 sv = ckmalloc(sizeof (struct redirtab));
116 for (i = 0 ; i < 10 ; i++)
117 sv->renamed[i] = EMPTY;
118 sv->next = redirlist;
119 redirlist = sv;
120 }
121 for (n = redir ; n ; n = n->nfile.next) {
122 fd = n->nfile.fd;
123 try = 0;
124 if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
125 n->ndup.dupfd == fd)
126 continue; /* redirect from/to same file descriptor */
127
128 if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
129 INTOFF;
130again:
131 if ((i = fcntl(fd, F_DUPFD, 10)) == -1) {
132 switch (errno) {
133 case EBADF:
134 if (!try) {
135 openredirect(n, memory);
136 try++;
137 goto again;
138 }
139 /* FALLTHROUGH*/
140 default:
141 INTON;
142 error("%d: %s", fd, strerror(errno));
143 break;
144 }
145 }
146 if (!try) {
147 sv->renamed[fd] = i;
148 }
149 INTON;
150 }
151 if (fd == 0)
152 fd0_redirected++;
153 if (!try)
154 openredirect(n, memory);
155 }
156 if (memory[1])
157 out1 = &memout;
158 if (memory[2])
159 out2 = &memout;
160}
161
162
163STATIC void
164openredirect(union node *redir, char memory[10])
165{
166 struct stat sb;
167 int fd = redir->nfile.fd;
168 char *fname;
169 int f;
170
171 /*
172 * We suppress interrupts so that we won't leave open file
173 * descriptors around. This may not be such a good idea because
174 * an open of a device or a fifo can block indefinitely.
175 */
176 INTOFF;
177 memory[fd] = 0;
178 switch (redir->nfile.type) {
179 case NFROM:
180 fname = redir->nfile.expfname;
181 if ((f = open(fname, O_RDONLY)) < 0)
182 error("cannot open %s: %s", fname, errmsg(errno, E_OPEN));
183movefd:
184 if (f != fd) {
185 close(fd);
186 copyfd(f, fd);
187 close(f);
188 }
189 break;
190 case NFROMTO:
191 fname = redir->nfile.expfname;
192#ifdef O_CREAT
193 if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0)
194 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
195#else
196 if ((f = open(fname, O_RDWR, 0666)) < 0) {
197 if (errno != ENOENT)
198 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
199 else if ((f = creat(fname, 0666)) < 0)
200 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
201 else {
202 close(f);
203 if ((f = open(fname, O_RDWR)) < 0) {
204 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
205 remove(fname);
206 }
207 }
208 }
209#endif
210 goto movefd;
211 case NTO:
212 fname = redir->nfile.expfname;
213 if (Cflag && stat(fname, &sb) != -1 && S_ISREG(sb.st_mode))
214 error("cannot create %s: %s", fname,
215 errmsg(EEXIST, E_CREAT));
216#ifdef O_CREAT
217 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
218 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
219#else
220 if ((f = creat(fname, 0666)) < 0)
221 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
222#endif
223 goto movefd;
224 case NCLOBBER:
225 fname = redir->nfile.expfname;
226 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
227 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
228 goto movefd;
229 case NAPPEND:
230 fname = redir->nfile.expfname;
231#ifdef O_APPEND
232 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
233 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
234#else
235 if ((f = open(fname, O_WRONLY)) < 0
236 && (f = creat(fname, 0666)) < 0)
237 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT));
238 lseek(f, (off_t)0, 2);
239#endif
240 goto movefd;
241 case NTOFD:
242 case NFROMFD:
243 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
244 if (memory[redir->ndup.dupfd])
245 memory[fd] = 1;
246 else {
247 close(fd);
248 copyfd(redir->ndup.dupfd, fd);
249 }
250 } else
251 close(fd);
252 break;
253 case NHERE:
254 case NXHERE:
255 f = openhere(redir);
256 goto movefd;
257 default:
258 abort();
259 }
260 INTON;
261}
262
263
264/*
265 * Handle here documents. Normally we fork off a process to write the
266 * data to a pipe. If the document is short, we can stuff the data in
267 * the pipe without forking.
268 */
269
270STATIC int
271openhere(union node *redir)
272{
273 int pip[2];
274 int len = 0;
275
276 if (pipe(pip) < 0)
277 error("Pipe call failed: %s", strerror(errno));
278 if (redir->type == NHERE) {
279 len = strlen(redir->nhere.doc->narg.text);
280 if (len <= PIPESIZE) {
281 xwrite(pip[1], redir->nhere.doc->narg.text, len);
282 goto out;
283 }
284 }
285 if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
286 close(pip[0]);
287 signal(SIGINT, SIG_IGN);
288 signal(SIGQUIT, SIG_IGN);
289 signal(SIGHUP, SIG_IGN);
290#ifdef SIGTSTP
291 signal(SIGTSTP, SIG_IGN);
292#endif
293 signal(SIGPIPE, SIG_DFL);
294 if (redir->type == NHERE)
295 xwrite(pip[1], redir->nhere.doc->narg.text, len);
296 else
297 expandhere(redir->nhere.doc, pip[1]);
298 _exit(0);
299 }
300out:
301 close(pip[1]);
302 return pip[0];
303}
304
305
306
307/*
308 * Undo the effects of the last redirection.
309 */
310
311void
312popredir(void)
313{
314 struct redirtab *rp = redirlist;
315 int i;
316
317 for (i = 0 ; i < 10 ; i++) {
318 if (rp->renamed[i] != EMPTY) {
319 if (i == 0)
320 fd0_redirected--;
321 close(i);
322 if (rp->renamed[i] >= 0) {
323 copyfd(rp->renamed[i], i);
324 close(rp->renamed[i]);
325 }
326 }
327 }
328 INTOFF;
329 redirlist = rp->next;
330 ckfree(rp);
331 INTON;
332}
333
334/*
335 * Undo all redirections. Called on error or interrupt.
336 */
337
338#ifdef mkinit
339
340INCLUDE "redir.h"
341
342RESET {
343 while (redirlist)
344 popredir();
345}
346
347SHELLPROC {
348 clearredir();
349}
350
351#endif
352
353/* Return true if fd 0 has already been redirected at least once. */
354int
355fd0_redirected_p(void)
356{
357 return fd0_redirected != 0;
358}
359
360/*
361 * Discard all saved file descriptors.
362 */
363
364void
365clearredir(void)
366{
367 struct redirtab *rp;
368 int i;
369
370 for (rp = redirlist ; rp ; rp = rp->next) {
371 for (i = 0 ; i < 10 ; i++) {
372 if (rp->renamed[i] >= 0) {
373 close(rp->renamed[i]);
374 }
375 rp->renamed[i] = EMPTY;
376 }
377 }
378}
379
380
381
382/*
383 * Copy a file descriptor to be >= to. Returns -1
384 * if the source file descriptor is closed, EMPTY if there are no unused
385 * file descriptors left.
386 */
387
388int
389copyfd(int from, int to)
390{
391 int newfd;
392
393 newfd = fcntl(from, F_DUPFD, to);
394 if (newfd < 0) {
395 if (errno == EMFILE)
396 return EMPTY;
397 else
398 error("%d: %s", from, strerror(errno));
399 }
400 return newfd;
401}