xref: /dragonfly/bin/sh/input.c (revision e65bc1c3) 
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. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  * @(#)input.c	8.3 (Berkeley) 6/9/95
33  * $FreeBSD: head/bin/sh/input.c 245676 2013-01-19 22:12:08Z jilles $
34  */
35 
36 #include <stdio.h>	/* defines BUFSIZ */
37 #include <fcntl.h>
38 #include <errno.h>
39 #include <unistd.h>
40 #include <stdlib.h>
41 #include <string.h>
42 
43 /*
44  * This file implements the input routines used by the parser.
45  */
46 
47 #include "shell.h"
48 #include "redir.h"
49 #include "syntax.h"
50 #include "input.h"
51 #include "output.h"
52 #include "options.h"
53 #include "memalloc.h"
54 #include "error.h"
55 #include "alias.h"
56 #include "parser.h"
57 #include "myhistedit.h"
58 #include "trap.h"
59 
60 #define EOF_NLEFT -99		/* value of parsenleft when EOF pushed back */
61 
62 struct strpush {
63 	struct strpush *prev;	/* preceding string on stack */
64 	char *prevstring;
65 	int prevnleft;
66 	int prevlleft;
67 	struct alias *ap;	/* if push was associated with an alias */
68 };
69 
70 /*
71  * The parsefile structure pointed to by the global variable parsefile
72  * contains information about the current file being read.
73  */
74 
75 struct parsefile {
76 	struct parsefile *prev;	/* preceding file on stack */
77 	int linno;		/* current line */
78 	int fd;			/* file descriptor (or -1 if string) */
79 	int nleft;		/* number of chars left in this line */
80 	int lleft;		/* number of lines left in this buffer */
81 	char *nextc;		/* next char in buffer */
82 	char *buf;		/* input buffer */
83 	struct strpush *strpush; /* for pushing strings at this level */
84 	struct strpush basestrpush; /* so pushing one is fast */
85 };
86 
87 
88 int plinno = 1;			/* input line number */
89 int parsenleft;			/* copy of parsefile->nleft */
90 MKINIT int parselleft;		/* copy of parsefile->lleft */
91 char *parsenextc;		/* copy of parsefile->nextc */
92 static char basebuf[BUFSIZ + 1];/* buffer for top level input file */
93 static struct parsefile basepf = {	/* top level input file */
94 	.nextc = basebuf,
95 	.buf = basebuf
96 };
97 static struct parsefile *parsefile = &basepf;	/* current input file */
98 int whichprompt;		/* 1 == PS1, 2 == PS2 */
99 
100 EditLine *el;			/* cookie for editline package */
101 
102 static void pushfile(void);
103 static int preadfd(void);
104 static void popstring(void);
105 
106 #ifdef mkinit
107 INCLUDE <stdio.h>
108 INCLUDE "input.h"
109 INCLUDE "error.h"
110 
111 RESET {
112 	popallfiles();
113 	parselleft = parsenleft = 0;	/* clear input buffer */
114 }
115 #endif
116 
117 
118 /*
119  * Read a line from the script.
120  */
121 
122 char *
123 pfgets(char *line, int len)
124 {
125 	char *p = line;
126 	int nleft = len;
127 	int c;
128 
129 	while (--nleft > 0) {
130 		c = pgetc_macro();
131 		if (c == PEOF) {
132 			if (p == line)
133 				return NULL;
134 			break;
135 		}
136 		*p++ = c;
137 		if (c == '\n')
138 			break;
139 	}
140 	*p = '\0';
141 	return line;
142 }
143 
144 
145 
146 /*
147  * Read a character from the script, returning PEOF on end of file.
148  * Nul characters in the input are silently discarded.
149  */
150 
151 int
152 pgetc(void)
153 {
154 	return pgetc_macro();
155 }
156 
157 
158 static int
159 preadfd(void)
160 {
161 	int nr;
162 	parsenextc = parsefile->buf;
163 
164 #ifndef NO_HISTORY
165 	if (el != NULL && gotwinch) {
166 		gotwinch = 0;
167 		el_resize(el);
168 	}
169 #endif
170 retry:
171 #ifndef NO_HISTORY
172 	if (parsefile->fd == 0 && el) {
173 		static const char *rl_cp;
174 		static int el_len;
175 
176 		if (rl_cp == NULL)
177 			rl_cp = el_gets(el, &el_len);
178 		if (rl_cp == NULL)
179 			nr = el_len == 0 ? 0 : -1;
180 		else {
181 			nr = el_len;
182 			if (nr > BUFSIZ)
183 				nr = BUFSIZ;
184 			memcpy(parsenextc, rl_cp, nr);
185 			if (nr != el_len) {
186 				el_len -= nr;
187 				rl_cp += nr;
188 			} else
189 				rl_cp = NULL;
190 		}
191 	} else
192 #endif
193 		nr = read(parsefile->fd, parsenextc, BUFSIZ);
194 
195 	if (nr <= 0) {
196                 if (nr < 0) {
197                         if (errno == EINTR)
198                                 goto retry;
199                         if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
200                                 int flags = fcntl(0, F_GETFL, 0);
201                                 if (flags >= 0 && flags & O_NONBLOCK) {
202                                         flags &=~ O_NONBLOCK;
203                                         if (fcntl(0, F_SETFL, flags) >= 0) {
204 						out2fmt_flush("sh: turning off NDELAY mode\n");
205                                                 goto retry;
206                                         }
207                                 }
208                         }
209                 }
210                 nr = -1;
211 	}
212 	return nr;
213 }
214 
215 /*
216  * Refill the input buffer and return the next input character:
217  *
218  * 1) If a string was pushed back on the input, pop it;
219  * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
220  *    from a string so we can't refill the buffer, return EOF.
221  * 3) If there is more in this buffer, use it else call read to fill it.
222  * 4) Process input up to the next newline, deleting nul characters.
223  */
224 
225 int
226 preadbuffer(void)
227 {
228 	char *p, *q;
229 	int more;
230 	int something;
231 	char savec;
232 
233 	if (parsefile->strpush) {
234 		popstring();
235 		if (--parsenleft >= 0)
236 			return (*parsenextc++);
237 	}
238 	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
239 		return PEOF;
240 	flushout(&output);
241 	flushout(&errout);
242 
243 again:
244 	if (parselleft <= 0) {
245 		if ((parselleft = preadfd()) == -1) {
246 			parselleft = parsenleft = EOF_NLEFT;
247 			return PEOF;
248 		}
249 	}
250 
251 	q = p = parsenextc;
252 
253 	/* delete nul characters */
254 	something = 0;
255 	for (more = 1; more;) {
256 		switch (*p) {
257 		case '\0':
258 			p++;	/* Skip nul */
259 			goto check;
260 
261 		case '\t':
262 		case ' ':
263 			break;
264 
265 		case '\n':
266 			parsenleft = q - parsenextc;
267 			more = 0; /* Stop processing here */
268 			break;
269 
270 		default:
271 			something = 1;
272 			break;
273 		}
274 
275 		*q++ = *p++;
276 check:
277 		if (--parselleft <= 0) {
278 			parsenleft = q - parsenextc - 1;
279 			if (parsenleft < 0)
280 				goto again;
281 			*q = '\0';
282 			more = 0;
283 		}
284 	}
285 
286 	savec = *q;
287 	*q = '\0';
288 
289 #ifndef NO_HISTORY
290 	if (parsefile->fd == 0 && hist && something) {
291 		HistEvent he;
292 		INTOFF;
293 		history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
294 		    parsenextc);
295 		INTON;
296 	}
297 #endif
298 
299 	if (vflag) {
300 		out2str(parsenextc);
301 		flushout(out2);
302 	}
303 
304 	*q = savec;
305 
306 	return *parsenextc++;
307 }
308 
309 /*
310  * Returns if we are certain we are at EOF. Does not cause any more input
311  * to be read from the outside world.
312  */
313 
314 int
315 preadateof(void)
316 {
317 	if (parsenleft > 0)
318 		return 0;
319 	if (parsefile->strpush)
320 		return 0;
321 	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
322 		return 1;
323 	return 0;
324 }
325 
326 /*
327  * Undo the last call to pgetc.  Only one character may be pushed back.
328  * PEOF may be pushed back.
329  */
330 
331 void
332 pungetc(void)
333 {
334 	parsenleft++;
335 	parsenextc--;
336 }
337 
338 /*
339  * Push a string back onto the input at this current parsefile level.
340  * We handle aliases this way.
341  */
342 void
343 pushstring(char *s, int len, struct alias *ap)
344 {
345 	struct strpush *sp;
346 
347 	INTOFF;
348 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
349 	if (parsefile->strpush) {
350 		sp = ckmalloc(sizeof (struct strpush));
351 		sp->prev = parsefile->strpush;
352 		parsefile->strpush = sp;
353 	} else
354 		sp = parsefile->strpush = &(parsefile->basestrpush);
355 	sp->prevstring = parsenextc;
356 	sp->prevnleft = parsenleft;
357 	sp->prevlleft = parselleft;
358 	sp->ap = ap;
359 	if (ap)
360 		ap->flag |= ALIASINUSE;
361 	parsenextc = s;
362 	parsenleft = len;
363 	INTON;
364 }
365 
366 static void
367 popstring(void)
368 {
369 	struct strpush *sp = parsefile->strpush;
370 
371 	INTOFF;
372 	parsenextc = sp->prevstring;
373 	parsenleft = sp->prevnleft;
374 	parselleft = sp->prevlleft;
375 /*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/
376 	if (sp->ap)
377 		sp->ap->flag &= ~ALIASINUSE;
378 	parsefile->strpush = sp->prev;
379 	if (sp != &(parsefile->basestrpush))
380 		ckfree(sp);
381 	INTON;
382 }
383 
384 /*
385  * Set the input to take input from a file.  If push is set, push the
386  * old input onto the stack first.
387  */
388 
389 void
390 setinputfile(const char *fname, int push)
391 {
392 	int fd;
393 	int fd2;
394 
395 	INTOFF;
396 	if ((fd = open(fname, O_RDONLY)) < 0)
397 		error("cannot open %s: %s", fname, strerror(errno));
398 	if (fd < 10) {
399 		fd2 = fcntl(fd, F_DUPFD, 10);
400 		close(fd);
401 		if (fd2 < 0)
402 			error("Out of file descriptors");
403 		fd = fd2;
404 	}
405 	setinputfd(fd, push);
406 	INTON;
407 }
408 
409 
410 /*
411  * Like setinputfile, but takes an open file descriptor.  Call this with
412  * interrupts off.
413  */
414 
415 void
416 setinputfd(int fd, int push)
417 {
418 	fcntl(fd, F_SETFD, FD_CLOEXEC);
419 	if (push) {
420 		pushfile();
421 		parsefile->buf = ckmalloc(BUFSIZ + 1);
422 	}
423 	if (parsefile->fd > 0)
424 		close(parsefile->fd);
425 	parsefile->fd = fd;
426 	if (parsefile->buf == NULL)
427 		parsefile->buf = ckmalloc(BUFSIZ + 1);
428 	parselleft = parsenleft = 0;
429 	plinno = 1;
430 }
431 
432 
433 /*
434  * Like setinputfile, but takes input from a string.
435  */
436 
437 void
438 setinputstring(char *string, int push)
439 {
440 	INTOFF;
441 	if (push)
442 		pushfile();
443 	parsenextc = string;
444 	parselleft = parsenleft = strlen(string);
445 	parsefile->buf = NULL;
446 	plinno = 1;
447 	INTON;
448 }
449 
450 
451 
452 /*
453  * To handle the "." command, a stack of input files is used.  Pushfile
454  * adds a new entry to the stack and popfile restores the previous level.
455  */
456 
457 static void
458 pushfile(void)
459 {
460 	struct parsefile *pf;
461 
462 	parsefile->nleft = parsenleft;
463 	parsefile->lleft = parselleft;
464 	parsefile->nextc = parsenextc;
465 	parsefile->linno = plinno;
466 	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
467 	pf->prev = parsefile;
468 	pf->fd = -1;
469 	pf->strpush = NULL;
470 	pf->basestrpush.prev = NULL;
471 	parsefile = pf;
472 }
473 
474 
475 void
476 popfile(void)
477 {
478 	struct parsefile *pf = parsefile;
479 
480 	INTOFF;
481 	if (pf->fd >= 0)
482 		close(pf->fd);
483 	if (pf->buf)
484 		ckfree(pf->buf);
485 	while (pf->strpush)
486 		popstring();
487 	parsefile = pf->prev;
488 	ckfree(pf);
489 	parsenleft = parsefile->nleft;
490 	parselleft = parsefile->lleft;
491 	parsenextc = parsefile->nextc;
492 	plinno = parsefile->linno;
493 	INTON;
494 }
495 
496 
497 /*
498  * Return current file (to go back to it later using popfilesupto()).
499  */
500 
501 struct parsefile *
502 getcurrentfile(void)
503 {
504 	return parsefile;
505 }
506 
507 
508 /*
509  * Pop files until the given file is on top again. Useful for regular
510  * builtins that read shell commands from files or strings.
511  * If the given file is not an active file, an error is raised.
512  */
513 
514 void
515 popfilesupto(struct parsefile *file)
516 {
517 	while (parsefile != file && parsefile != &basepf)
518 		popfile();
519 	if (parsefile != file)
520 		error("popfilesupto() misused");
521 }
522 
523 /*
524  * Return to top level.
525  */
526 
527 void
528 popallfiles(void)
529 {
530 	while (parsefile != &basepf)
531 		popfile();
532 }
533 
534 
535 
536 /*
537  * Close the file(s) that the shell is reading commands from.  Called
538  * after a fork is done.
539  */
540 
541 void
542 closescript(void)
543 {
544 	popallfiles();
545 	if (parsefile->fd > 0) {
546 		close(parsefile->fd);
547 		parsefile->fd = 0;
548 	}
549 }
550