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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 | |
6c604e0e | 12 | static char sccsid[] = "@(#)redir.c 5.3 (Berkeley) %G%"; |
b87c26db KB |
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" | |
6c604e0e | 27 | #include <sys/types.h> |
b87c26db KB |
28 | #include <signal.h> |
29 | #include <fcntl.h> | |
30 | #include <errno.h> | |
6c604e0e | 31 | #include <unistd.h> |
b87c26db KB |
32 | |
33 | ||
34 | #define EMPTY -2 /* marks an unused slot in redirtab */ | |
35 | #define PIPESIZE 4096 /* amount of buffering in a pipe */ | |
36 | ||
37 | ||
38 | MKINIT | |
39 | struct redirtab { | |
40 | struct redirtab *next; | |
41 | short renamed[10]; | |
42 | }; | |
43 | ||
44 | ||
45 | MKINIT struct redirtab *redirlist; | |
46 | ||
47 | ||
48 | #ifdef __STDC__ | |
49 | STATIC void openredirect(union node *, char *); | |
50 | STATIC int openhere(union node *); | |
51 | #else | |
52 | STATIC void openredirect(); | |
53 | STATIC int openhere(); | |
54 | #endif | |
55 | ||
56 | ||
57 | ||
58 | /* | |
59 | * Process a list of redirection commands. If the REDIR_PUSH flag is set, | |
60 | * old file descriptors are stashed away so that the redirection can be | |
61 | * undone by calling popredir. If the REDIR_BACKQ flag is set, then the | |
62 | * standard output, and the standard error if it becomes a duplicate of | |
63 | * stdout, is saved in memory. | |
64 | */ | |
65 | ||
66 | void | |
67 | redirect(redir, flags) | |
68 | union node *redir; | |
69 | int flags; | |
70 | { | |
71 | union node *n; | |
72 | struct redirtab *sv; | |
73 | int i; | |
74 | int fd; | |
75 | char memory[10]; /* file descriptors to write to memory */ | |
76 | ||
77 | for (i = 10 ; --i >= 0 ; ) | |
78 | memory[i] = 0; | |
79 | memory[1] = flags & REDIR_BACKQ; | |
80 | if (flags & REDIR_PUSH) { | |
81 | sv = ckmalloc(sizeof (struct redirtab)); | |
82 | for (i = 0 ; i < 10 ; i++) | |
83 | sv->renamed[i] = EMPTY; | |
84 | sv->next = redirlist; | |
85 | redirlist = sv; | |
86 | } | |
87 | for (n = redir ; n ; n = n->nfile.next) { | |
88 | fd = n->nfile.fd; | |
89 | if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { | |
90 | INTOFF; | |
91 | if ((i = copyfd(fd, 10)) != EMPTY) { | |
92 | sv->renamed[fd] = i; | |
93 | close(fd); | |
94 | } | |
95 | INTON; | |
96 | if (i == EMPTY) | |
97 | error("Out of file descriptors"); | |
98 | } else { | |
99 | close(fd); | |
100 | } | |
101 | openredirect(n, memory); | |
102 | } | |
103 | if (memory[1]) | |
104 | out1 = &memout; | |
105 | if (memory[2]) | |
106 | out2 = &memout; | |
107 | } | |
108 | ||
109 | ||
110 | STATIC void | |
111 | openredirect(redir, memory) | |
112 | union node *redir; | |
113 | char memory[10]; | |
114 | { | |
115 | int fd = redir->nfile.fd; | |
116 | char *fname; | |
117 | int f; | |
118 | ||
119 | /* | |
120 | * We suppress interrupts so that we won't leave open file | |
121 | * descriptors around. This may not be such a good idea because | |
122 | * an open of a device or a fifo can block indefinitely. | |
123 | */ | |
124 | INTOFF; | |
125 | memory[fd] = 0; | |
126 | switch (redir->nfile.type) { | |
127 | case NFROM: | |
128 | fname = redir->nfile.expfname; | |
129 | if ((f = open(fname, O_RDONLY)) < 0) | |
130 | error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); | |
131 | movefd: | |
132 | if (f != fd) { | |
133 | copyfd(f, fd); | |
134 | close(f); | |
135 | } | |
136 | break; | |
137 | case NTO: | |
138 | fname = redir->nfile.expfname; | |
139 | #ifdef O_CREAT | |
140 | if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) | |
141 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
142 | #else | |
143 | if ((f = creat(fname, 0666)) < 0) | |
144 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
145 | #endif | |
146 | goto movefd; | |
147 | case NAPPEND: | |
148 | fname = redir->nfile.expfname; | |
149 | #ifdef O_APPEND | |
150 | if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) | |
151 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
152 | #else | |
153 | if ((f = open(fname, O_WRONLY)) < 0 | |
154 | && (f = creat(fname, 0666)) < 0) | |
155 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); | |
6c604e0e | 156 | lseek(f, (off_t)0, 2); |
b87c26db KB |
157 | #endif |
158 | goto movefd; | |
159 | case NTOFD: | |
160 | case NFROMFD: | |
161 | if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ | |
162 | if (memory[redir->ndup.dupfd]) | |
163 | memory[fd] = 1; | |
164 | else | |
165 | copyfd(redir->ndup.dupfd, fd); | |
166 | } | |
167 | break; | |
168 | case NHERE: | |
169 | case NXHERE: | |
170 | f = openhere(redir); | |
171 | goto movefd; | |
172 | default: | |
173 | abort(); | |
174 | } | |
175 | INTON; | |
176 | } | |
177 | ||
178 | ||
179 | /* | |
180 | * Handle here documents. Normally we fork off a process to write the | |
181 | * data to a pipe. If the document is short, we can stuff the data in | |
182 | * the pipe without forking. | |
183 | */ | |
184 | ||
185 | STATIC int | |
186 | openhere(redir) | |
187 | union node *redir; | |
188 | { | |
189 | int pip[2]; | |
190 | int len; | |
191 | ||
192 | if (pipe(pip) < 0) | |
193 | error("Pipe call failed"); | |
194 | if (redir->type == NHERE) { | |
195 | len = strlen(redir->nhere.doc->narg.text); | |
196 | if (len <= PIPESIZE) { | |
197 | xwrite(pip[1], redir->nhere.doc->narg.text, len); | |
198 | goto out; | |
199 | } | |
200 | } | |
201 | if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { | |
202 | close(pip[0]); | |
203 | signal(SIGINT, SIG_IGN); | |
204 | signal(SIGQUIT, SIG_IGN); | |
205 | signal(SIGHUP, SIG_IGN); | |
206 | #ifdef SIGTSTP | |
207 | signal(SIGTSTP, SIG_IGN); | |
208 | #endif | |
209 | signal(SIGPIPE, SIG_DFL); | |
210 | if (redir->type == NHERE) | |
211 | xwrite(pip[1], redir->nhere.doc->narg.text, len); | |
212 | else | |
213 | expandhere(redir->nhere.doc, pip[1]); | |
214 | _exit(0); | |
215 | } | |
216 | out: | |
217 | close(pip[1]); | |
218 | return pip[0]; | |
219 | } | |
220 | ||
221 | ||
222 | ||
223 | /* | |
224 | * Undo the effects of the last redirection. | |
225 | */ | |
226 | ||
227 | void | |
228 | popredir() { | |
229 | register struct redirtab *rp = redirlist; | |
230 | int i; | |
231 | ||
232 | for (i = 0 ; i < 10 ; i++) { | |
233 | if (rp->renamed[i] != EMPTY) { | |
234 | close(i); | |
235 | if (rp->renamed[i] >= 0) { | |
236 | copyfd(rp->renamed[i], i); | |
237 | close(rp->renamed[i]); | |
238 | } | |
239 | } | |
240 | } | |
241 | INTOFF; | |
242 | redirlist = rp->next; | |
243 | ckfree(rp); | |
244 | INTON; | |
245 | } | |
246 | ||
247 | ||
248 | ||
249 | /* | |
250 | * Undo all redirections. Called on error or interrupt. | |
251 | */ | |
252 | ||
253 | #ifdef mkinit | |
254 | ||
255 | INCLUDE "redir.h" | |
256 | ||
257 | RESET { | |
258 | while (redirlist) | |
259 | popredir(); | |
260 | } | |
261 | ||
262 | SHELLPROC { | |
263 | clearredir(); | |
264 | } | |
265 | ||
266 | #endif | |
267 | ||
268 | ||
269 | /* | |
270 | * Discard all saved file descriptors. | |
271 | */ | |
272 | ||
273 | void | |
274 | clearredir() { | |
275 | register struct redirtab *rp; | |
276 | int i; | |
277 | ||
278 | for (rp = redirlist ; rp ; rp = rp->next) { | |
279 | for (i = 0 ; i < 10 ; i++) { | |
280 | if (rp->renamed[i] >= 0) { | |
281 | close(rp->renamed[i]); | |
282 | } | |
283 | rp->renamed[i] = EMPTY; | |
284 | } | |
285 | } | |
286 | } | |
287 | ||
288 | ||
289 | ||
290 | /* | |
83be9114 | 291 | * Copy a file descriptor to be >= to. Returns -1 |
b87c26db KB |
292 | * if the source file descriptor is closed, EMPTY if there are no unused |
293 | * file descriptors left. | |
294 | */ | |
295 | ||
296 | int | |
297 | copyfd(from, to) { | |
b87c26db KB |
298 | int newfd; |
299 | ||
300 | newfd = fcntl(from, F_DUPFD, to); | |
301 | if (newfd < 0 && errno == EMFILE) | |
302 | return EMPTY; | |
303 | return newfd; | |
b87c26db | 304 | } |