input.c revision 21673 
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. 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.
35 *
36 *	$FreeBSD: head/bin/sh/input.c 21673 1997-01-14 07:20:47Z jkh $
37 */
38
39#ifndef lint
40static char const sccsid[] = "@(#)input.c	8.3 (Berkeley) 6/9/95";
41#endif /* not lint */
42
43#include <stdio.h>	/* defines BUFSIZ */
44#include <fcntl.h>
45#include <errno.h>
46#include <unistd.h>
47#include <stdlib.h>
48#include <string.h>
49
50/*
51 * This file implements the input routines used by the parser.
52 */
53
54#include "shell.h"
55#include "redir.h"
56#include "syntax.h"
57#include "input.h"
58#include "output.h"
59#include "options.h"
60#include "memalloc.h"
61#include "error.h"
62#include "alias.h"
63#include "parser.h"
64#include "myhistedit.h"
65
66#define EOF_NLEFT -99		/* value of parsenleft when EOF pushed back */
67
68MKINIT
69struct strpush {
70	struct strpush *prev;	/* preceding string on stack */
71	char *prevstring;
72	int prevnleft;
73	int prevlleft;
74	struct alias *ap;	/* if push was associated with an alias */
75};
76
77/*
78 * The parsefile structure pointed to by the global variable parsefile
79 * contains information about the current file being read.
80 */
81
82MKINIT
83struct parsefile {
84	struct parsefile *prev;	/* preceding file on stack */
85	int linno;		/* current line */
86	int fd;			/* file descriptor (or -1 if string) */
87	int nleft;		/* number of chars left in this line */
88	int lleft;		/* number of lines left in this buffer */
89	char *nextc;		/* next char in buffer */
90	char *buf;		/* input buffer */
91	struct strpush *strpush; /* for pushing strings at this level */
92	struct strpush basestrpush; /* so pushing one is fast */
93};
94
95
96int plinno = 1;			/* input line number */
97MKINIT int parsenleft;		/* copy of parsefile->nleft */
98MKINIT int parselleft;		/* copy of parsefile->lleft */
99char *parsenextc;		/* copy of parsefile->nextc */
100MKINIT struct parsefile basepf;	/* top level input file */
101char basebuf[BUFSIZ];		/* buffer for top level input file */
102struct parsefile *parsefile = &basepf;	/* current input file */
103int init_editline = 0;		/* editline library initialized? */
104int whichprompt;		/* 1 == PS1, 2 == PS2 */
105
106EditLine *el;			/* cookie for editline package */
107
108STATIC void pushfile __P((void));
109static int pread __P((void));
110
111#ifdef mkinit
112INCLUDE "input.h"
113INCLUDE "error.h"
114
115INIT {
116	extern char basebuf[];
117
118	basepf.nextc = basepf.buf = basebuf;
119}
120
121RESET {
122	if (exception != EXSHELLPROC)
123		parselleft = parsenleft = 0;	/* clear input buffer */
124	popallfiles();
125}
126
127SHELLPROC {
128	popallfiles();
129}
130#endif
131
132
133/*
134 * Read a line from the script.
135 */
136
137char *
138pfgets(line, len)
139	char *line;
140	int len;
141{
142	register char *p = line;
143	int nleft = len;
144	int c;
145
146	while (--nleft > 0) {
147		c = pgetc_macro();
148		if (c == PEOF) {
149			if (p == line)
150				return NULL;
151			break;
152		}
153		*p++ = c;
154		if (c == '\n')
155			break;
156	}
157	*p = '\0';
158	return line;
159}
160
161
162
163/*
164 * Read a character from the script, returning PEOF on end of file.
165 * Nul characters in the input are silently discarded.
166 */
167
168int
169pgetc()
170{
171	return pgetc_macro();
172}
173
174
175static int
176pread()
177{
178	int nr;
179	parsenextc = parsefile->buf;
180
181retry:
182	if (parsefile->fd == 0 && el) {
183		const char *rl_cp;
184
185		rl_cp = el_gets(el, &nr);
186		if (rl_cp == NULL)
187			nr = 0;
188		else {
189			/* XXX - BUFSIZE should redesign so not necessary */
190			(void) strcpy(parsenextc, rl_cp);
191		}
192	} else {
193		nr = read(parsefile->fd, parsenextc, BUFSIZ - 1);
194	}
195
196	if (nr <= 0) {
197                if (nr < 0) {
198                        if (errno == EINTR)
199                                goto retry;
200                        if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
201                                int flags = fcntl(0, F_GETFL, 0);
202                                if (flags >= 0 && flags & O_NONBLOCK) {
203                                        flags &=~ O_NONBLOCK;
204                                        if (fcntl(0, F_SETFL, flags) >= 0) {
205						out2str("sh: turning off NDELAY mode\n");
206                                                goto retry;
207                                        }
208                                }
209                        }
210                }
211                nr = -1;
212	}
213	return nr;
214}
215
216/*
217 * Refill the input buffer and return the next input character:
218 *
219 * 1) If a string was pushed back on the input, pop it;
220 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
221 *    from a string so we can't refill the buffer, return EOF.
222 * 3) If there is more in this buffer, use it else call read to fill it.
223 * 4) Process input up to the next newline, deleting nul characters.
224 */
225
226int
227preadbuffer()
228{
229	char *p, *q;
230	int more;
231	int something;
232	extern EditLine *el;
233	char savec;
234
235	if (parsefile->strpush) {
236		popstring();
237		if (--parsenleft >= 0)
238			return (*parsenextc++);
239	}
240	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
241		return PEOF;
242	flushout(&output);
243	flushout(&errout);
244
245again:
246	if (parselleft <= 0) {
247		if ((parselleft = pread()) == -1) {
248			parselleft = parsenleft = EOF_NLEFT;
249			return PEOF;
250		}
251	}
252
253	q = p = parsenextc;
254
255	/* delete nul characters */
256	something = 0;
257	for (more = 1; more;) {
258		switch (*p) {
259		case '\0':
260			p++;	/* Skip nul */
261			goto check;
262
263		case '\t':
264		case ' ':
265			break;
266
267		case '\n':
268			parsenleft = q - parsenextc;
269			more = 0; /* Stop processing here */
270			break;
271
272		default:
273			something = 1;
274			break;
275		}
276
277		*q++ = *p++;
278check:
279		if (--parselleft <= 0) {
280			parsenleft = q - parsenextc - 1;
281			if (parsenleft < 0)
282				goto again;
283			*q = '\0';
284			more = 0;
285		}
286	}
287
288	savec = *q;
289	*q = '\0';
290
291#ifndef NO_HISTORY
292	if (parsefile->fd == 0 && hist && something) {
293		INTOFF;
294		history(hist, whichprompt == 1 ? H_ENTER : H_ADD, 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 * Undo the last call to pgetc.  Only one character may be pushed back.
311 * PEOF may be pushed back.
312 */
313
314void
315pungetc() {
316	parsenleft++;
317	parsenextc--;
318}
319
320/*
321 * Push a string back onto the input at this current parsefile level.
322 * We handle aliases this way.
323 */
324void
325pushstring(s, len, ap)
326	char *s;
327	int len;
328	void *ap;
329	{
330	struct strpush *sp;
331
332	INTOFF;
333/*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
334	if (parsefile->strpush) {
335		sp = ckmalloc(sizeof (struct strpush));
336		sp->prev = parsefile->strpush;
337		parsefile->strpush = sp;
338	} else
339		sp = parsefile->strpush = &(parsefile->basestrpush);
340	sp->prevstring = parsenextc;
341	sp->prevnleft = parsenleft;
342	sp->prevlleft = parselleft;
343	sp->ap = (struct alias *)ap;
344	if (ap)
345		((struct alias *)ap)->flag |= ALIASINUSE;
346	parsenextc = s;
347	parsenleft = len;
348	INTON;
349}
350
351void
352popstring()
353{
354	struct strpush *sp = parsefile->strpush;
355
356	INTOFF;
357	parsenextc = sp->prevstring;
358	parsenleft = sp->prevnleft;
359	parselleft = sp->prevlleft;
360/*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
361	if (sp->ap)
362		sp->ap->flag &= ~ALIASINUSE;
363	parsefile->strpush = sp->prev;
364	if (sp != &(parsefile->basestrpush))
365		ckfree(sp);
366	INTON;
367}
368
369/*
370 * Set the input to take input from a file.  If push is set, push the
371 * old input onto the stack first.
372 */
373
374void
375setinputfile(fname, push)
376	char *fname;
377	int push;
378{
379	int fd;
380	int fd2;
381
382	INTOFF;
383	if ((fd = open(fname, O_RDONLY)) < 0)
384		error("Can't open %s", fname);
385	if (fd < 10) {
386		fd2 = copyfd(fd, 10);
387		close(fd);
388		if (fd2 < 0)
389			error("Out of file descriptors");
390		fd = fd2;
391	}
392	setinputfd(fd, push);
393	INTON;
394}
395
396
397/*
398 * Like setinputfile, but takes an open file descriptor.  Call this with
399 * interrupts off.
400 */
401
402void
403setinputfd(fd, push)
404	int fd, push;
405{
406	if (push) {
407		pushfile();
408		parsefile->buf = ckmalloc(BUFSIZ);
409	}
410	if (parsefile->fd > 0)
411		close(parsefile->fd);
412	parsefile->fd = fd;
413	if (parsefile->buf == NULL)
414		parsefile->buf = ckmalloc(BUFSIZ);
415	parselleft = parsenleft = 0;
416	plinno = 1;
417}
418
419
420/*
421 * Like setinputfile, but takes input from a string.
422 */
423
424void
425setinputstring(string, push)
426	char *string;
427	int push;
428	{
429	INTOFF;
430	if (push)
431		pushfile();
432	parsenextc = string;
433	parselleft = parsenleft = strlen(string);
434	parsefile->buf = NULL;
435	plinno = 1;
436	INTON;
437}
438
439
440
441/*
442 * To handle the "." command, a stack of input files is used.  Pushfile
443 * adds a new entry to the stack and popfile restores the previous level.
444 */
445
446STATIC void
447pushfile() {
448	struct parsefile *pf;
449
450	parsefile->nleft = parsenleft;
451	parsefile->lleft = parselleft;
452	parsefile->nextc = parsenextc;
453	parsefile->linno = plinno;
454	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
455	pf->prev = parsefile;
456	pf->fd = -1;
457	pf->strpush = NULL;
458	pf->basestrpush.prev = NULL;
459	parsefile = pf;
460}
461
462
463void
464popfile() {
465	struct parsefile *pf = parsefile;
466
467	INTOFF;
468	if (pf->fd >= 0)
469		close(pf->fd);
470	if (pf->buf)
471		ckfree(pf->buf);
472	while (pf->strpush)
473		popstring();
474	parsefile = pf->prev;
475	ckfree(pf);
476	parsenleft = parsefile->nleft;
477	parselleft = parsefile->lleft;
478	parsenextc = parsefile->nextc;
479	plinno = parsefile->linno;
480	INTON;
481}
482
483
484/*
485 * Return to top level.
486 */
487
488void
489popallfiles() {
490	while (parsefile != &basepf)
491		popfile();
492}
493
494
495
496/*
497 * Close the file(s) that the shell is reading commands from.  Called
498 * after a fork is done.
499 */
500
501void
502closescript() {
503	popallfiles();
504	if (parsefile->fd > 0) {
505		close(parsefile->fd);
506		parsefile->fd = 0;
507	}
508}
509