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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 $
010f7689 38 * $DragonFly: src/bin/sh/redir.c,v 1.4 2007/01/06 03:44:04 pavalos 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)
010f7689 178 error("cannot open %s: %s", fname, strerror(errno));
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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;
984263bc 188 if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0)
010f7689 189 error("cannot create %s: %s", fname, strerror(errno));
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190 goto movefd;
191 case NTO:
192 fname = redir->nfile.expfname;
193 if (Cflag && stat(fname, &sb) != -1 && S_ISREG(sb.st_mode))
194 error("cannot create %s: %s", fname,
010f7689 195 strerror(EEXIST));
984263bc 196 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
010f7689 197 error("cannot create %s: %s", fname, strerror(errno));
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198 goto movefd;
199 case NCLOBBER:
200 fname = redir->nfile.expfname;
201 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
010f7689 202 error("cannot create %s: %s", fname, strerror(errno));
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203 goto movefd;
204 case NAPPEND:
205 fname = redir->nfile.expfname;
984263bc 206 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
010f7689 207 error("cannot create %s: %s", fname, strerror(errno));
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208 goto movefd;
209 case NTOFD:
210 case NFROMFD:
211 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
212 if (memory[redir->ndup.dupfd])
213 memory[fd] = 1;
214 else {
215 close(fd);
216 copyfd(redir->ndup.dupfd, fd);
217 }
218 } else
219 close(fd);
220 break;
221 case NHERE:
222 case NXHERE:
223 f = openhere(redir);
224 goto movefd;
225 default:
226 abort();
227 }
228 INTON;
229}
230
231
232/*
233 * Handle here documents. Normally we fork off a process to write the
234 * data to a pipe. If the document is short, we can stuff the data in
235 * the pipe without forking.
236 */
237
238STATIC int
239openhere(union node *redir)
240{
241 int pip[2];
242 int len = 0;
243
244 if (pipe(pip) < 0)
245 error("Pipe call failed: %s", strerror(errno));
246 if (redir->type == NHERE) {
247 len = strlen(redir->nhere.doc->narg.text);
248 if (len <= PIPESIZE) {
249 xwrite(pip[1], redir->nhere.doc->narg.text, len);
250 goto out;
251 }
252 }
253 if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
254 close(pip[0]);
255 signal(SIGINT, SIG_IGN);
256 signal(SIGQUIT, SIG_IGN);
257 signal(SIGHUP, SIG_IGN);
984263bc 258 signal(SIGTSTP, SIG_IGN);
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259 signal(SIGPIPE, SIG_DFL);
260 if (redir->type == NHERE)
261 xwrite(pip[1], redir->nhere.doc->narg.text, len);
262 else
263 expandhere(redir->nhere.doc, pip[1]);
264 _exit(0);
265 }
266out:
267 close(pip[1]);
268 return pip[0];
269}
270
271
272
273/*
274 * Undo the effects of the last redirection.
275 */
276
277void
278popredir(void)
279{
280 struct redirtab *rp = redirlist;
281 int i;
282
283 for (i = 0 ; i < 10 ; i++) {
284 if (rp->renamed[i] != EMPTY) {
285 if (i == 0)
286 fd0_redirected--;
287 close(i);
288 if (rp->renamed[i] >= 0) {
289 copyfd(rp->renamed[i], i);
290 close(rp->renamed[i]);
291 }
292 }
293 }
294 INTOFF;
295 redirlist = rp->next;
296 ckfree(rp);
297 INTON;
298}
299
300/*
301 * Undo all redirections. Called on error or interrupt.
302 */
303
304#ifdef mkinit
305
306INCLUDE "redir.h"
307
308RESET {
309 while (redirlist)
310 popredir();
311}
312
313SHELLPROC {
314 clearredir();
315}
316
317#endif
318
319/* Return true if fd 0 has already been redirected at least once. */
320int
321fd0_redirected_p(void)
322{
323 return fd0_redirected != 0;
324}
325
326/*
327 * Discard all saved file descriptors.
328 */
329
330void
331clearredir(void)
332{
333 struct redirtab *rp;
334 int i;
335
336 for (rp = redirlist ; rp ; rp = rp->next) {
337 for (i = 0 ; i < 10 ; i++) {
338 if (rp->renamed[i] >= 0) {
339 close(rp->renamed[i]);
340 }
341 rp->renamed[i] = EMPTY;
342 }
343 }
344}
345
346
347
348/*
349 * Copy a file descriptor to be >= to. Returns -1
350 * if the source file descriptor is closed, EMPTY if there are no unused
351 * file descriptors left.
352 */
353
354int
355copyfd(int from, int to)
356{
357 int newfd;
358
359 newfd = fcntl(from, F_DUPFD, to);
360 if (newfd < 0) {
361 if (errno == EMFILE)
362 return EMPTY;
363 else
364 error("%d: %s", from, strerror(errno));
365 }
366 return newfd;
367}