sh: Sync with FreeBSD
[dragonfly.git] / bin / sh / redir.c
CommitLineData
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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
99512ac4 37 * $FreeBSD: src/bin/sh/redir.c,v 1.34 2011/02/04 22:47:55 jilles Exp $
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38 */
39
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40#include <sys/types.h>
41#include <sys/stat.h>
42#include <signal.h>
43#include <string.h>
44#include <fcntl.h>
45#include <errno.h>
46#include <unistd.h>
47#include <stdlib.h>
48
49/*
50 * Code for dealing with input/output redirection.
51 */
52
53#include "shell.h"
54#include "nodes.h"
55#include "jobs.h"
56#include "expand.h"
57#include "redir.h"
58#include "output.h"
59#include "memalloc.h"
60#include "error.h"
61#include "options.h"
62
63
64#define EMPTY -2 /* marks an unused slot in redirtab */
99512ac4 65#define CLOSED -1 /* fd was not open before redir */
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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*/
99512ac4 83static int fd0_redirected = 0;
984263bc 84
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85static void openredirect(union node *, char[10 ]);
86static int openhere(union node *);
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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;
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104 char memory[10]; /* file descriptors to write to memory */
105
106 for (i = 10 ; --i >= 0 ; )
107 memory[i] = 0;
108 memory[1] = flags & REDIR_BACKQ;
109 if (flags & REDIR_PUSH) {
110 sv = ckmalloc(sizeof (struct redirtab));
111 for (i = 0 ; i < 10 ; i++)
112 sv->renamed[i] = EMPTY;
113 sv->next = redirlist;
114 redirlist = sv;
115 }
116 for (n = redir ; n ; n = n->nfile.next) {
117 fd = n->nfile.fd;
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118 if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
119 n->ndup.dupfd == fd)
120 continue; /* redirect from/to same file descriptor */
121
122 if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
123 INTOFF;
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124 if ((i = fcntl(fd, F_DUPFD, 10)) == -1) {
125 switch (errno) {
126 case EBADF:
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127 i = CLOSED;
128 break;
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129 default:
130 INTON;
131 error("%d: %s", fd, strerror(errno));
132 break;
133 }
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134 } else
135 (void)fcntl(i, F_SETFD, FD_CLOEXEC);
136 sv->renamed[fd] = i;
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137 INTON;
138 }
139 if (fd == 0)
140 fd0_redirected++;
99512ac4 141 openredirect(n, memory);
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142 }
143 if (memory[1])
144 out1 = &memout;
145 if (memory[2])
146 out2 = &memout;
147}
148
149
99512ac4 150static void
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151openredirect(union node *redir, char memory[10])
152{
153 struct stat sb;
154 int fd = redir->nfile.fd;
155 char *fname;
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156 int f = 0;
157 int e;
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158
159 /*
160 * We suppress interrupts so that we won't leave open file
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161 * descriptors around. Because the signal handler remains
162 * installed and we do not use system call restart, interrupts
163 * will still abort blocking opens such as fifos (they will fail
164 * with EINTR). There is, however, a race condition if an interrupt
165 * arrives after INTOFF and before open blocks.
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166 */
167 INTOFF;
168 memory[fd] = 0;
169 switch (redir->nfile.type) {
170 case NFROM:
171 fname = redir->nfile.expfname;
172 if ((f = open(fname, O_RDONLY)) < 0)
010f7689 173 error("cannot open %s: %s", fname, strerror(errno));
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174movefd:
175 if (f != fd) {
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176 if (dup2(f, fd) == -1) {
177 e = errno;
178 close(f);
179 error("%d: %s", fd, strerror(e));
180 }
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181 close(f);
182 }
183 break;
184 case NFROMTO:
185 fname = redir->nfile.expfname;
984263bc 186 if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0)
010f7689 187 error("cannot create %s: %s", fname, strerror(errno));
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188 goto movefd;
189 case NTO:
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190 if (Cflag) {
191 fname = redir->nfile.expfname;
192 if (stat(fname, &sb) == -1) {
193 if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0666)) < 0)
194 error("cannot create %s: %s", fname, strerror(errno));
195 } else if (!S_ISREG(sb.st_mode)) {
196 if ((f = open(fname, O_WRONLY, 0666)) < 0)
197 error("cannot create %s: %s", fname, strerror(errno));
198 if (fstat(f, &sb) != -1 && S_ISREG(sb.st_mode)) {
199 close(f);
200 error("cannot create %s: %s", fname,
201 strerror(EEXIST));
202 }
203 } else
204 error("cannot create %s: %s", fname,
205 strerror(EEXIST));
206 goto movefd;
207 }
208 /* FALLTHROUGH */
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209 case NCLOBBER:
210 fname = redir->nfile.expfname;
211 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0)
010f7689 212 error("cannot create %s: %s", fname, strerror(errno));
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213 goto movefd;
214 case NAPPEND:
215 fname = redir->nfile.expfname;
984263bc 216 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
010f7689 217 error("cannot create %s: %s", fname, strerror(errno));
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218 goto movefd;
219 case NTOFD:
220 case NFROMFD:
221 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
222 if (memory[redir->ndup.dupfd])
223 memory[fd] = 1;
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224 else {
225 if (dup2(redir->ndup.dupfd, fd) < 0)
226 error("%d: %s", redir->ndup.dupfd,
227 strerror(errno));
228 }
996bd0d6 229 } else {
984263bc 230 close(fd);
996bd0d6 231 }
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232 break;
233 case NHERE:
234 case NXHERE:
235 f = openhere(redir);
236 goto movefd;
237 default:
238 abort();
239 }
240 INTON;
241}
242
243
244/*
245 * Handle here documents. Normally we fork off a process to write the
246 * data to a pipe. If the document is short, we can stuff the data in
247 * the pipe without forking.
248 */
249
99512ac4 250static int
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251openhere(union node *redir)
252{
253 int pip[2];
254 int len = 0;
255
256 if (pipe(pip) < 0)
257 error("Pipe call failed: %s", strerror(errno));
258 if (redir->type == NHERE) {
259 len = strlen(redir->nhere.doc->narg.text);
260 if (len <= PIPESIZE) {
261 xwrite(pip[1], redir->nhere.doc->narg.text, len);
262 goto out;
263 }
264 }
2038fb68 265 if (forkshell(NULL, NULL, FORK_NOJOB) == 0) {
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266 close(pip[0]);
267 signal(SIGINT, SIG_IGN);
268 signal(SIGQUIT, SIG_IGN);
269 signal(SIGHUP, SIG_IGN);
984263bc 270 signal(SIGTSTP, SIG_IGN);
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271 signal(SIGPIPE, SIG_DFL);
272 if (redir->type == NHERE)
273 xwrite(pip[1], redir->nhere.doc->narg.text, len);
274 else
275 expandhere(redir->nhere.doc, pip[1]);
276 _exit(0);
277 }
278out:
279 close(pip[1]);
280 return pip[0];
281}
282
283
284
285/*
286 * Undo the effects of the last redirection.
287 */
288
289void
290popredir(void)
291{
292 struct redirtab *rp = redirlist;
293 int i;
294
295 for (i = 0 ; i < 10 ; i++) {
296 if (rp->renamed[i] != EMPTY) {
297 if (i == 0)
298 fd0_redirected--;
984263bc 299 if (rp->renamed[i] >= 0) {
996bd0d6 300 dup2(rp->renamed[i], i);
984263bc 301 close(rp->renamed[i]);
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302 } else {
303 close(i);
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304 }
305 }
306 }
307 INTOFF;
308 redirlist = rp->next;
309 ckfree(rp);
310 INTON;
311}
312
313/*
314 * Undo all redirections. Called on error or interrupt.
315 */
316
317#ifdef mkinit
318
319INCLUDE "redir.h"
320
321RESET {
322 while (redirlist)
323 popredir();
324}
325
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326#endif
327
328/* Return true if fd 0 has already been redirected at least once. */
329int
330fd0_redirected_p(void)
331{
332 return fd0_redirected != 0;
333}
334
335/*
336 * Discard all saved file descriptors.
337 */
338
339void
340clearredir(void)
341{
342 struct redirtab *rp;
343 int i;
344
345 for (rp = redirlist ; rp ; rp = rp->next) {
346 for (i = 0 ; i < 10 ; i++) {
347 if (rp->renamed[i] >= 0) {
348 close(rp->renamed[i]);
349 }
350 rp->renamed[i] = EMPTY;
351 }
352 }
353}