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15637ed4 RG |
1 | /*- |
2 | * Copyright (c) 1991 The Regents of the University of California. | |
3 | * 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. | |
15637ed4 RG |
35 | */ |
36 | ||
37 | #ifndef lint | |
78ed81a3 | 38 | /*static char sccsid[] = "from: @(#)redir.c 5.1 (Berkeley) 3/7/91";*/ |
39 | static char rcsid[] = "redir.c,v 1.5 1993/08/01 18:58:01 mycroft Exp"; | |
15637ed4 RG |
40 | #endif /* not lint */ |
41 | ||
42 | /* | |
43 | * Code for dealing with input/output redirection. | |
44 | */ | |
45 | ||
46 | #include "shell.h" | |
47 | #include "nodes.h" | |
48 | #include "jobs.h" | |
49 | #include "expand.h" | |
50 | #include "redir.h" | |
51 | #include "output.h" | |
52 | #include "memalloc.h" | |
53 | #include "error.h" | |
54 | #include <signal.h> | |
55 | #include <fcntl.h> | |
56 | #include <errno.h> | |
57 | ||
58 | ||
59 | #define EMPTY -2 /* marks an unused slot in redirtab */ | |
60 | #define PIPESIZE 4096 /* amount of buffering in a pipe */ | |
61 | ||
62 | ||
63 | MKINIT | |
64 | struct redirtab { | |
65 | struct redirtab *next; | |
66 | short renamed[10]; | |
67 | }; | |
68 | ||
69 | ||
70 | MKINIT struct redirtab *redirlist; | |
71 | ||
72 | /* We keep track of whether or not fd0 has been redirected. This is for | |
73 | background commands, where we want to redirect fd0 to /dev/null only | |
74 | if it hasn't already been redirected. */ | |
75 | int fd0_redirected = 0; | |
76 | ||
77 | #ifdef __STDC__ | |
78 | STATIC void openredirect(union node *, char *); | |
79 | STATIC int openhere(union node *); | |
80 | #else | |
81 | STATIC void openredirect(); | |
82 | STATIC int openhere(); | |
83 | #endif | |
84 | ||
85 | ||
86 | ||
87 | /* | |
88 | * Process a list of redirection commands. If the REDIR_PUSH flag is set, | |
89 | * old file descriptors are stashed away so that the redirection can be | |
90 | * undone by calling popredir. If the REDIR_BACKQ flag is set, then the | |
91 | * standard output, and the standard error if it becomes a duplicate of | |
92 | * stdout, is saved in memory. | |
93 | */ | |
94 | ||
95 | void | |
96 | redirect(redir, flags) | |
97 | union node *redir; | |
98 | int flags; | |
99 | { | |
100 | union node *n; | |
101 | struct redirtab *sv; | |
102 | int i; | |
103 | int fd; | |
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; | |
118 | if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { | |
119 | INTOFF; | |
120 | if ((i = copyfd(fd, 10)) != EMPTY) { | |
121 | sv->renamed[fd] = i; | |
122 | close(fd); | |
123 | } | |
124 | INTON; | |
125 | if (i == EMPTY) | |
126 | error("Out of file descriptors"); | |
127 | } else { | |
128 | close(fd); | |
129 | } | |
130 | if (fd == 0) | |
131 | fd0_redirected++; | |
132 | openredirect(n, memory); | |
133 | } | |
134 | if (memory[1]) | |
135 | out1 = &memout; | |
136 | if (memory[2]) | |
137 | out2 = &memout; | |
138 | } | |
139 | ||
140 | ||
141 | STATIC void | |
142 | openredirect(redir, memory) | |
143 | union node *redir; | |
144 | char memory[10]; | |
145 | { | |
146 | int fd = redir->nfile.fd; | |
147 | char *fname; | |
148 | int f; | |
149 | ||
150 | /* | |
151 | * We suppress interrupts so that we won't leave open file | |
152 | * descriptors around. This may not be such a good idea because | |
153 | * an open of a device or a fifo can block indefinitely. | |
154 | */ | |
155 | INTOFF; | |
156 | memory[fd] = 0; | |
157 | switch (redir->nfile.type) { | |
158 | case NFROM: | |
159 | fname = redir->nfile.expfname; | |
160 | if ((f = open(fname, O_RDONLY)) < 0) | |
161 | error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); | |
162 | movefd: | |
163 | if (f != fd) { | |
164 | copyfd(f, fd); | |
165 | close(f); | |
166 | } | |
167 | break; | |
168 | case NTO: | |
169 | fname = redir->nfile.expfname; | |
170 | #ifdef O_CREAT | |
171 | if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) | |
172 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
173 | #else | |
174 | if ((f = creat(fname, 0666)) < 0) | |
175 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
176 | #endif | |
177 | goto movefd; | |
178 | case NAPPEND: | |
179 | fname = redir->nfile.expfname; | |
180 | #ifdef O_APPEND | |
181 | if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) | |
182 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
183 | #else | |
184 | if ((f = open(fname, O_WRONLY)) < 0 | |
185 | && (f = creat(fname, 0666)) < 0) | |
186 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
187 | lseek(f, 0L, 2); | |
188 | #endif | |
189 | goto movefd; | |
190 | case NTOFD: | |
191 | case NFROMFD: | |
192 | if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ | |
193 | if (memory[redir->ndup.dupfd]) | |
194 | memory[fd] = 1; | |
195 | else | |
196 | copyfd(redir->ndup.dupfd, fd); | |
197 | } | |
198 | break; | |
199 | case NHERE: | |
200 | case NXHERE: | |
201 | f = openhere(redir); | |
202 | goto movefd; | |
203 | default: | |
204 | abort(); | |
205 | } | |
206 | INTON; | |
207 | } | |
208 | ||
209 | ||
210 | /* | |
211 | * Handle here documents. Normally we fork off a process to write the | |
212 | * data to a pipe. If the document is short, we can stuff the data in | |
213 | * the pipe without forking. | |
214 | */ | |
215 | ||
216 | STATIC int | |
217 | openhere(redir) | |
218 | union node *redir; | |
219 | { | |
220 | int pip[2]; | |
221 | int len; | |
222 | ||
223 | if (pipe(pip) < 0) | |
224 | error("Pipe call failed"); | |
225 | if (redir->type == NHERE) { | |
226 | len = strlen(redir->nhere.doc->narg.text); | |
227 | if (len <= PIPESIZE) { | |
228 | xwrite(pip[1], redir->nhere.doc->narg.text, len); | |
229 | goto out; | |
230 | } | |
231 | } | |
232 | if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { | |
233 | close(pip[0]); | |
234 | signal(SIGINT, SIG_IGN); | |
235 | signal(SIGQUIT, SIG_IGN); | |
236 | signal(SIGHUP, SIG_IGN); | |
237 | #ifdef SIGTSTP | |
238 | signal(SIGTSTP, SIG_IGN); | |
239 | #endif | |
240 | signal(SIGPIPE, SIG_DFL); | |
241 | if (redir->type == NHERE) | |
242 | xwrite(pip[1], redir->nhere.doc->narg.text, len); | |
243 | else | |
244 | expandhere(redir->nhere.doc, pip[1]); | |
245 | _exit(0); | |
246 | } | |
247 | out: | |
248 | close(pip[1]); | |
249 | return pip[0]; | |
250 | } | |
251 | ||
252 | ||
253 | ||
254 | /* | |
255 | * Undo the effects of the last redirection. | |
256 | */ | |
257 | ||
258 | void | |
259 | popredir() { | |
260 | register struct redirtab *rp = redirlist; | |
261 | int i; | |
262 | ||
263 | for (i = 0 ; i < 10 ; i++) { | |
264 | if (rp->renamed[i] != EMPTY) { | |
265 | if (i == 0) | |
266 | fd0_redirected--; | |
267 | close(i); | |
268 | if (rp->renamed[i] >= 0) { | |
269 | copyfd(rp->renamed[i], i); | |
270 | close(rp->renamed[i]); | |
271 | } | |
272 | } | |
273 | } | |
274 | INTOFF; | |
275 | redirlist = rp->next; | |
276 | ckfree(rp); | |
277 | INTON; | |
278 | } | |
279 | ||
280 | ||
281 | ||
282 | /* | |
283 | * Undo all redirections. Called on error or interrupt. | |
284 | */ | |
285 | ||
286 | #ifdef mkinit | |
287 | ||
288 | INCLUDE "redir.h" | |
289 | ||
290 | RESET { | |
291 | while (redirlist) | |
292 | popredir(); | |
293 | } | |
294 | ||
295 | SHELLPROC { | |
296 | clearredir(); | |
297 | } | |
298 | ||
299 | #endif | |
300 | ||
301 | ||
302 | /* | |
303 | * Discard all saved file descriptors. | |
304 | */ | |
305 | ||
306 | void | |
307 | clearredir() { | |
308 | register struct redirtab *rp; | |
309 | int i; | |
310 | ||
311 | for (rp = redirlist ; rp ; rp = rp->next) { | |
312 | for (i = 0 ; i < 10 ; i++) { | |
313 | if (rp->renamed[i] >= 0) { | |
314 | close(rp->renamed[i]); | |
315 | } | |
316 | rp->renamed[i] = EMPTY; | |
317 | } | |
318 | } | |
319 | } | |
320 | ||
321 | ||
322 | ||
323 | /* | |
324 | * Copy a file descriptor, like the F_DUPFD option of fcntl. Returns -1 | |
325 | * if the source file descriptor is closed, EMPTY if there are no unused | |
326 | * file descriptors left. | |
327 | */ | |
328 | ||
329 | int | |
330 | copyfd(from, to) { | |
331 | #ifdef F_DUPFD | |
332 | int newfd; | |
333 | ||
334 | newfd = fcntl(from, F_DUPFD, to); | |
335 | if (newfd < 0 && errno == EMFILE) | |
336 | return EMPTY; | |
337 | return newfd; | |
338 | #else | |
339 | char toclose[32]; | |
340 | int i; | |
341 | int newfd; | |
342 | int e; | |
343 | ||
344 | for (i = 0 ; i < to ; i++) | |
345 | toclose[i] = 0; | |
346 | INTOFF; | |
347 | while ((newfd = dup(from)) >= 0 && newfd < to) | |
348 | toclose[newfd] = 1; | |
349 | e = errno; | |
350 | for (i = 0 ; i < to ; i++) { | |
351 | if (toclose[i]) | |
352 | close(i); | |
353 | } | |
354 | INTON; | |
355 | if (newfd < 0 && e == EMFILE) | |
356 | return EMPTY; | |
357 | return newfd; | |
358 | #endif | |
359 | } | |
360 | ||
361 | /* Return true if fd 0 has already been redirected at least once. */ | |
362 | int | |
363 | fd0_redirected_p () { | |
364 | return fd0_redirected != 0; | |
365 | } |