input.c revision 218306 
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 * 4. 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
33#ifndef lint
34#if 0
35static char sccsid[] = "@(#)input.c	8.3 (Berkeley) 6/9/95";
36#endif
37#endif /* not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: head/bin/sh/input.c 218306 2011-02-04 22:47:55Z jilles $");
40
41#include <stdio.h>	/* defines BUFSIZ */
42#include <fcntl.h>
43#include <errno.h>
44#include <unistd.h>
45#include <stdlib.h>
46#include <string.h>
47
48/*
49 * This file implements the input routines used by the parser.
50 */
51
52#include "shell.h"
53#include "redir.h"
54#include "syntax.h"
55#include "input.h"
56#include "output.h"
57#include "options.h"
58#include "memalloc.h"
59#include "error.h"
60#include "alias.h"
61#include "parser.h"
62#include "myhistedit.h"
63#include "trap.h"
64
65#define EOF_NLEFT -99		/* value of parsenleft when EOF pushed back */
66
67MKINIT
68struct strpush {
69	struct strpush *prev;	/* preceding string on stack */
70	char *prevstring;
71	int prevnleft;
72	int prevlleft;
73	struct alias *ap;	/* if push was associated with an alias */
74};
75
76/*
77 * The parsefile structure pointed to by the global variable parsefile
78 * contains information about the current file being read.
79 */
80
81MKINIT
82struct parsefile {
83	struct parsefile *prev;	/* preceding file on stack */
84	int linno;		/* current line */
85	int fd;			/* file descriptor (or -1 if string) */
86	int nleft;		/* number of chars left in this line */
87	int lleft;		/* number of lines left in this buffer */
88	char *nextc;		/* next char in buffer */
89	char *buf;		/* input buffer */
90	struct strpush *strpush; /* for pushing strings at this level */
91	struct strpush basestrpush; /* so pushing one is fast */
92};
93
94
95int plinno = 1;			/* input line number */
96int parsenleft;			/* copy of parsefile->nleft */
97MKINIT int parselleft;		/* copy of parsefile->lleft */
98char *parsenextc;		/* copy of parsefile->nextc */
99MKINIT struct parsefile basepf;	/* top level input file */
100char basebuf[BUFSIZ];		/* buffer for top level input file */
101static struct parsefile *parsefile = &basepf;	/* current input file */
102int init_editline = 0;		/* editline library initialized? */
103int whichprompt;		/* 1 == PS1, 2 == PS2 */
104
105EditLine *el;			/* cookie for editline package */
106
107static void pushfile(void);
108static int preadfd(void);
109
110#ifdef mkinit
111INCLUDE "input.h"
112INCLUDE "error.h"
113
114MKINIT char basebuf[];
115
116INIT {
117	basepf.nextc = basepf.buf = basebuf;
118}
119
120RESET {
121	popallfiles();
122	parselleft = parsenleft = 0;	/* clear input buffer */
123}
124#endif
125
126
127/*
128 * Read a line from the script.
129 */
130
131char *
132pfgets(char *line, int len)
133{
134	char *p = line;
135	int nleft = len;
136	int c;
137
138	while (--nleft > 0) {
139		c = pgetc_macro();
140		if (c == PEOF) {
141			if (p == line)
142				return NULL;
143			break;
144		}
145		*p++ = c;
146		if (c == '\n')
147			break;
148	}
149	*p = '\0';
150	return line;
151}
152
153
154
155/*
156 * Read a character from the script, returning PEOF on end of file.
157 * Nul characters in the input are silently discarded.
158 */
159
160int
161pgetc(void)
162{
163	return pgetc_macro();
164}
165
166
167static int
168preadfd(void)
169{
170	int nr;
171	parsenextc = parsefile->buf;
172
173#ifndef NO_HISTORY
174	if (el != NULL && gotwinch) {
175		gotwinch = 0;
176		el_resize(el);
177	}
178#endif
179retry:
180#ifndef NO_HISTORY
181	if (parsefile->fd == 0 && el) {
182		static const char *rl_cp;
183		static int el_len;
184
185		if (rl_cp == NULL)
186			rl_cp = el_gets(el, &el_len);
187		if (rl_cp == NULL)
188			nr = 0;
189		else {
190			nr = el_len;
191			if (nr > BUFSIZ - 1)
192				nr = BUFSIZ - 1;
193			memcpy(parsenextc, rl_cp, nr);
194			if (nr != el_len) {
195				el_len -= nr;
196				rl_cp += nr;
197			} else
198				rl_cp = NULL;
199		}
200	} else
201#endif
202		nr = read(parsefile->fd, parsenextc, BUFSIZ - 1);
203
204	if (nr <= 0) {
205                if (nr < 0) {
206                        if (errno == EINTR)
207                                goto retry;
208                        if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
209                                int flags = fcntl(0, F_GETFL, 0);
210                                if (flags >= 0 && flags & O_NONBLOCK) {
211                                        flags &=~ O_NONBLOCK;
212                                        if (fcntl(0, F_SETFL, flags) >= 0) {
213						out2fmt_flush("sh: turning off NDELAY mode\n");
214                                                goto retry;
215                                        }
216                                }
217                        }
218                }
219                nr = -1;
220	}
221	return nr;
222}
223
224/*
225 * Refill the input buffer and return the next input character:
226 *
227 * 1) If a string was pushed back on the input, pop it;
228 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
229 *    from a string so we can't refill the buffer, return EOF.
230 * 3) If there is more in this buffer, use it else call read to fill it.
231 * 4) Process input up to the next newline, deleting nul characters.
232 */
233
234int
235preadbuffer(void)
236{
237	char *p, *q;
238	int more;
239	int something;
240	char savec;
241
242	if (parsefile->strpush) {
243		popstring();
244		if (--parsenleft >= 0)
245			return (*parsenextc++);
246	}
247	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
248		return PEOF;
249	flushout(&output);
250	flushout(&errout);
251
252again:
253	if (parselleft <= 0) {
254		if ((parselleft = preadfd()) == -1) {
255			parselleft = parsenleft = EOF_NLEFT;
256			return PEOF;
257		}
258	}
259
260	q = p = parsenextc;
261
262	/* delete nul characters */
263	something = 0;
264	for (more = 1; more;) {
265		switch (*p) {
266		case '\0':
267			p++;	/* Skip nul */
268			goto check;
269
270		case '\t':
271		case ' ':
272			break;
273
274		case '\n':
275			parsenleft = q - parsenextc;
276			more = 0; /* Stop processing here */
277			break;
278
279		default:
280			something = 1;
281			break;
282		}
283
284		*q++ = *p++;
285check:
286		if (--parselleft <= 0) {
287			parsenleft = q - parsenextc - 1;
288			if (parsenleft < 0)
289				goto again;
290			*q = '\0';
291			more = 0;
292		}
293	}
294
295	savec = *q;
296	*q = '\0';
297
298#ifndef NO_HISTORY
299	if (parsefile->fd == 0 && hist && something) {
300		HistEvent he;
301		INTOFF;
302		history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
303		    parsenextc);
304		INTON;
305	}
306#endif
307
308	if (vflag) {
309		out2str(parsenextc);
310		flushout(out2);
311	}
312
313	*q = savec;
314
315	return *parsenextc++;
316}
317
318/*
319 * Returns if we are certain we are at EOF. Does not cause any more input
320 * to be read from the outside world.
321 */
322
323int
324preadateof(void)
325{
326	if (parsenleft > 0)
327		return 0;
328	if (parsefile->strpush)
329		return 0;
330	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
331		return 1;
332	return 0;
333}
334
335/*
336 * Undo the last call to pgetc.  Only one character may be pushed back.
337 * PEOF may be pushed back.
338 */
339
340void
341pungetc(void)
342{
343	parsenleft++;
344	parsenextc--;
345}
346
347/*
348 * Push a string back onto the input at this current parsefile level.
349 * We handle aliases this way.
350 */
351void
352pushstring(char *s, int len, void *ap)
353{
354	struct strpush *sp;
355
356	INTOFF;
357/*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
358	if (parsefile->strpush) {
359		sp = ckmalloc(sizeof (struct strpush));
360		sp->prev = parsefile->strpush;
361		parsefile->strpush = sp;
362	} else
363		sp = parsefile->strpush = &(parsefile->basestrpush);
364	sp->prevstring = parsenextc;
365	sp->prevnleft = parsenleft;
366	sp->prevlleft = parselleft;
367	sp->ap = (struct alias *)ap;
368	if (ap)
369		((struct alias *)ap)->flag |= ALIASINUSE;
370	parsenextc = s;
371	parsenleft = len;
372	INTON;
373}
374
375void
376popstring(void)
377{
378	struct strpush *sp = parsefile->strpush;
379
380	INTOFF;
381	parsenextc = sp->prevstring;
382	parsenleft = sp->prevnleft;
383	parselleft = sp->prevlleft;
384/*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/
385	if (sp->ap)
386		sp->ap->flag &= ~ALIASINUSE;
387	parsefile->strpush = sp->prev;
388	if (sp != &(parsefile->basestrpush))
389		ckfree(sp);
390	INTON;
391}
392
393/*
394 * Set the input to take input from a file.  If push is set, push the
395 * old input onto the stack first.
396 */
397
398void
399setinputfile(const char *fname, int push)
400{
401	int fd;
402	int fd2;
403
404	INTOFF;
405	if ((fd = open(fname, O_RDONLY)) < 0)
406		error("Can't open %s: %s", fname, strerror(errno));
407	if (fd < 10) {
408		fd2 = fcntl(fd, F_DUPFD, 10);
409		close(fd);
410		if (fd2 < 0)
411			error("Out of file descriptors");
412		fd = fd2;
413	}
414	setinputfd(fd, push);
415	INTON;
416}
417
418
419/*
420 * Like setinputfile, but takes an open file descriptor.  Call this with
421 * interrupts off.
422 */
423
424void
425setinputfd(int fd, int push)
426{
427	(void)fcntl(fd, F_SETFD, FD_CLOEXEC);
428	if (push) {
429		pushfile();
430		parsefile->buf = ckmalloc(BUFSIZ);
431	}
432	if (parsefile->fd > 0)
433		close(parsefile->fd);
434	parsefile->fd = fd;
435	if (parsefile->buf == NULL)
436		parsefile->buf = ckmalloc(BUFSIZ);
437	parselleft = parsenleft = 0;
438	plinno = 1;
439}
440
441
442/*
443 * Like setinputfile, but takes input from a string.
444 */
445
446void
447setinputstring(char *string, int push)
448{
449	INTOFF;
450	if (push)
451		pushfile();
452	parsenextc = string;
453	parselleft = parsenleft = strlen(string);
454	parsefile->buf = NULL;
455	plinno = 1;
456	INTON;
457}
458
459
460
461/*
462 * To handle the "." command, a stack of input files is used.  Pushfile
463 * adds a new entry to the stack and popfile restores the previous level.
464 */
465
466static void
467pushfile(void)
468{
469	struct parsefile *pf;
470
471	parsefile->nleft = parsenleft;
472	parsefile->lleft = parselleft;
473	parsefile->nextc = parsenextc;
474	parsefile->linno = plinno;
475	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
476	pf->prev = parsefile;
477	pf->fd = -1;
478	pf->strpush = NULL;
479	pf->basestrpush.prev = NULL;
480	parsefile = pf;
481}
482
483
484void
485popfile(void)
486{
487	struct parsefile *pf = parsefile;
488
489	INTOFF;
490	if (pf->fd >= 0)
491		close(pf->fd);
492	if (pf->buf)
493		ckfree(pf->buf);
494	while (pf->strpush)
495		popstring();
496	parsefile = pf->prev;
497	ckfree(pf);
498	parsenleft = parsefile->nleft;
499	parselleft = parsefile->lleft;
500	parsenextc = parsefile->nextc;
501	plinno = parsefile->linno;
502	INTON;
503}
504
505
506/*
507 * Return current file (to go back to it later using popfilesupto()).
508 */
509
510struct parsefile *
511getcurrentfile(void)
512{
513	return parsefile;
514}
515
516
517/*
518 * Pop files until the given file is on top again. Useful for regular
519 * builtins that read shell commands from files or strings.
520 * If the given file is not an active file, an error is raised.
521 */
522
523void
524popfilesupto(struct parsefile *file)
525{
526	while (parsefile != file && parsefile != &basepf)
527		popfile();
528	if (parsefile != file)
529		error("popfilesupto() misused");
530}
531
532/*
533 * Return to top level.
534 */
535
536void
537popallfiles(void)
538{
539	while (parsefile != &basepf)
540		popfile();
541}
542
543
544
545/*
546 * Close the file(s) that the shell is reading commands from.  Called
547 * after a fork is done.
548 */
549
550void
551closescript(void)
552{
553	popallfiles();
554	if (parsefile->fd > 0) {
555		close(parsefile->fd);
556		parsefile->fd = 0;
557	}
558}
559