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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 | * %sccs.include.redist.c% | |
9 | */ | |
10 | ||
11 | #ifndef lint | |
12 | static char sccsid[] = "@(#)redir.c 5.1 (Berkeley) %G%"; | |
13 | #endif /* not lint */ | |
14 | ||
15 | /* | |
16 | * Code for dealing with input/output redirection. | |
17 | */ | |
18 | ||
19 | #include "shell.h" | |
20 | #include "nodes.h" | |
21 | #include "jobs.h" | |
22 | #include "expand.h" | |
23 | #include "redir.h" | |
24 | #include "output.h" | |
25 | #include "memalloc.h" | |
26 | #include "error.h" | |
27 | #include <signal.h> | |
28 | #include <fcntl.h> | |
29 | #include <errno.h> | |
30 | ||
31 | ||
32 | #define EMPTY -2 /* marks an unused slot in redirtab */ | |
33 | #define PIPESIZE 4096 /* amount of buffering in a pipe */ | |
34 | ||
35 | ||
36 | MKINIT | |
37 | struct redirtab { | |
38 | struct redirtab *next; | |
39 | short renamed[10]; | |
40 | }; | |
41 | ||
42 | ||
43 | MKINIT struct redirtab *redirlist; | |
44 | ||
45 | ||
46 | #ifdef __STDC__ | |
47 | STATIC void openredirect(union node *, char *); | |
48 | STATIC int openhere(union node *); | |
49 | #else | |
50 | STATIC void openredirect(); | |
51 | STATIC int openhere(); | |
52 | #endif | |
53 | ||
54 | ||
55 | ||
56 | /* | |
57 | * Process a list of redirection commands. If the REDIR_PUSH flag is set, | |
58 | * old file descriptors are stashed away so that the redirection can be | |
59 | * undone by calling popredir. If the REDIR_BACKQ flag is set, then the | |
60 | * standard output, and the standard error if it becomes a duplicate of | |
61 | * stdout, is saved in memory. | |
62 | */ | |
63 | ||
64 | void | |
65 | redirect(redir, flags) | |
66 | union node *redir; | |
67 | int flags; | |
68 | { | |
69 | union node *n; | |
70 | struct redirtab *sv; | |
71 | int i; | |
72 | int fd; | |
73 | char memory[10]; /* file descriptors to write to memory */ | |
74 | ||
75 | for (i = 10 ; --i >= 0 ; ) | |
76 | memory[i] = 0; | |
77 | memory[1] = flags & REDIR_BACKQ; | |
78 | if (flags & REDIR_PUSH) { | |
79 | sv = ckmalloc(sizeof (struct redirtab)); | |
80 | for (i = 0 ; i < 10 ; i++) | |
81 | sv->renamed[i] = EMPTY; | |
82 | sv->next = redirlist; | |
83 | redirlist = sv; | |
84 | } | |
85 | for (n = redir ; n ; n = n->nfile.next) { | |
86 | fd = n->nfile.fd; | |
87 | if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { | |
88 | INTOFF; | |
89 | if ((i = copyfd(fd, 10)) != EMPTY) { | |
90 | sv->renamed[fd] = i; | |
91 | close(fd); | |
92 | } | |
93 | INTON; | |
94 | if (i == EMPTY) | |
95 | error("Out of file descriptors"); | |
96 | } else { | |
97 | close(fd); | |
98 | } | |
99 | openredirect(n, memory); | |
100 | } | |
101 | if (memory[1]) | |
102 | out1 = &memout; | |
103 | if (memory[2]) | |
104 | out2 = &memout; | |
105 | } | |
106 | ||
107 | ||
108 | STATIC void | |
109 | openredirect(redir, memory) | |
110 | union node *redir; | |
111 | char memory[10]; | |
112 | { | |
113 | int fd = redir->nfile.fd; | |
114 | char *fname; | |
115 | int f; | |
116 | ||
117 | /* | |
118 | * We suppress interrupts so that we won't leave open file | |
119 | * descriptors around. This may not be such a good idea because | |
120 | * an open of a device or a fifo can block indefinitely. | |
121 | */ | |
122 | INTOFF; | |
123 | memory[fd] = 0; | |
124 | switch (redir->nfile.type) { | |
125 | case NFROM: | |
126 | fname = redir->nfile.expfname; | |
127 | if ((f = open(fname, O_RDONLY)) < 0) | |
128 | error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); | |
129 | movefd: | |
130 | if (f != fd) { | |
131 | copyfd(f, fd); | |
132 | close(f); | |
133 | } | |
134 | break; | |
135 | case NTO: | |
136 | fname = redir->nfile.expfname; | |
137 | #ifdef O_CREAT | |
138 | if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) | |
139 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
140 | #else | |
141 | if ((f = creat(fname, 0666)) < 0) | |
142 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
143 | #endif | |
144 | goto movefd; | |
145 | case NAPPEND: | |
146 | fname = redir->nfile.expfname; | |
147 | #ifdef O_APPEND | |
148 | if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) | |
149 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
150 | #else | |
151 | if ((f = open(fname, O_WRONLY)) < 0 | |
152 | && (f = creat(fname, 0666)) < 0) | |
153 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
154 | lseek(f, 0L, 2); | |
155 | #endif | |
156 | goto movefd; | |
157 | case NTOFD: | |
158 | case NFROMFD: | |
159 | if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ | |
160 | if (memory[redir->ndup.dupfd]) | |
161 | memory[fd] = 1; | |
162 | else | |
163 | copyfd(redir->ndup.dupfd, fd); | |
164 | } | |
165 | break; | |
166 | case NHERE: | |
167 | case NXHERE: | |
168 | f = openhere(redir); | |
169 | goto movefd; | |
170 | default: | |
171 | abort(); | |
172 | } | |
173 | INTON; | |
174 | } | |
175 | ||
176 | ||
177 | /* | |
178 | * Handle here documents. Normally we fork off a process to write the | |
179 | * data to a pipe. If the document is short, we can stuff the data in | |
180 | * the pipe without forking. | |
181 | */ | |
182 | ||
183 | STATIC int | |
184 | openhere(redir) | |
185 | union node *redir; | |
186 | { | |
187 | int pip[2]; | |
188 | int len; | |
189 | ||
190 | if (pipe(pip) < 0) | |
191 | error("Pipe call failed"); | |
192 | if (redir->type == NHERE) { | |
193 | len = strlen(redir->nhere.doc->narg.text); | |
194 | if (len <= PIPESIZE) { | |
195 | xwrite(pip[1], redir->nhere.doc->narg.text, len); | |
196 | goto out; | |
197 | } | |
198 | } | |
199 | if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { | |
200 | close(pip[0]); | |
201 | signal(SIGINT, SIG_IGN); | |
202 | signal(SIGQUIT, SIG_IGN); | |
203 | signal(SIGHUP, SIG_IGN); | |
204 | #ifdef SIGTSTP | |
205 | signal(SIGTSTP, SIG_IGN); | |
206 | #endif | |
207 | signal(SIGPIPE, SIG_DFL); | |
208 | if (redir->type == NHERE) | |
209 | xwrite(pip[1], redir->nhere.doc->narg.text, len); | |
210 | else | |
211 | expandhere(redir->nhere.doc, pip[1]); | |
212 | _exit(0); | |
213 | } | |
214 | out: | |
215 | close(pip[1]); | |
216 | return pip[0]; | |
217 | } | |
218 | ||
219 | ||
220 | ||
221 | /* | |
222 | * Undo the effects of the last redirection. | |
223 | */ | |
224 | ||
225 | void | |
226 | popredir() { | |
227 | register struct redirtab *rp = redirlist; | |
228 | int i; | |
229 | ||
230 | for (i = 0 ; i < 10 ; i++) { | |
231 | if (rp->renamed[i] != EMPTY) { | |
232 | close(i); | |
233 | if (rp->renamed[i] >= 0) { | |
234 | copyfd(rp->renamed[i], i); | |
235 | close(rp->renamed[i]); | |
236 | } | |
237 | } | |
238 | } | |
239 | INTOFF; | |
240 | redirlist = rp->next; | |
241 | ckfree(rp); | |
242 | INTON; | |
243 | } | |
244 | ||
245 | ||
246 | ||
247 | /* | |
248 | * Undo all redirections. Called on error or interrupt. | |
249 | */ | |
250 | ||
251 | #ifdef mkinit | |
252 | ||
253 | INCLUDE "redir.h" | |
254 | ||
255 | RESET { | |
256 | while (redirlist) | |
257 | popredir(); | |
258 | } | |
259 | ||
260 | SHELLPROC { | |
261 | clearredir(); | |
262 | } | |
263 | ||
264 | #endif | |
265 | ||
266 | ||
267 | /* | |
268 | * Discard all saved file descriptors. | |
269 | */ | |
270 | ||
271 | void | |
272 | clearredir() { | |
273 | register struct redirtab *rp; | |
274 | int i; | |
275 | ||
276 | for (rp = redirlist ; rp ; rp = rp->next) { | |
277 | for (i = 0 ; i < 10 ; i++) { | |
278 | if (rp->renamed[i] >= 0) { | |
279 | close(rp->renamed[i]); | |
280 | } | |
281 | rp->renamed[i] = EMPTY; | |
282 | } | |
283 | } | |
284 | } | |
285 | ||
286 | ||
287 | ||
288 | /* | |
289 | * Copy a file descriptor, like the F_DUPFD option of fcntl. Returns -1 | |
290 | * if the source file descriptor is closed, EMPTY if there are no unused | |
291 | * file descriptors left. | |
292 | */ | |
293 | ||
294 | int | |
295 | copyfd(from, to) { | |
296 | #ifdef F_DUPFD | |
297 | int newfd; | |
298 | ||
299 | newfd = fcntl(from, F_DUPFD, to); | |
300 | if (newfd < 0 && errno == EMFILE) | |
301 | return EMPTY; | |
302 | return newfd; | |
303 | #else | |
304 | char toclose[32]; | |
305 | int i; | |
306 | int newfd; | |
307 | int e; | |
308 | ||
309 | for (i = 0 ; i < to ; i++) | |
310 | toclose[i] = 0; | |
311 | INTOFF; | |
312 | while ((newfd = dup(from)) >= 0 && newfd < to) | |
313 | toclose[newfd] = 1; | |
314 | e = errno; | |
315 | for (i = 0 ; i < to ; i++) { | |
316 | if (toclose[i]) | |
317 | close(i); | |
318 | } | |
319 | INTON; | |
320 | if (newfd < 0 && e == EMFILE) | |
321 | return EMPTY; | |
322 | return newfd; | |
323 | #endif | |
324 | } |