input.c revision 90111 
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
37#ifndef lint
38#if 0
39static char sccsid[] = "@(#)input.c	8.3 (Berkeley) 6/9/95";
40#endif
41static const char rcsid[] =
42  "$FreeBSD: head/bin/sh/input.c 90111 2002-02-02 06:50:57Z imp $";
43#endif /* not lint */
44
45#include <stdio.h>	/* defines BUFSIZ */
46#include <fcntl.h>
47#include <errno.h>
48#include <unistd.h>
49#include <stdlib.h>
50#include <string.h>
51
52/*
53 * This file implements the input routines used by the parser.
54 */
55
56#include "shell.h"
57#include "redir.h"
58#include "syntax.h"
59#include "input.h"
60#include "output.h"
61#include "options.h"
62#include "memalloc.h"
63#include "error.h"
64#include "alias.h"
65#include "parser.h"
66#include "myhistedit.h"
67
68#define EOF_NLEFT -99		/* value of parsenleft when EOF pushed back */
69
70MKINIT
71struct strpush {
72	struct strpush *prev;	/* preceding string on stack */
73	char *prevstring;
74	int prevnleft;
75	int prevlleft;
76	struct alias *ap;	/* if push was associated with an alias */
77};
78
79/*
80 * The parsefile structure pointed to by the global variable parsefile
81 * contains information about the current file being read.
82 */
83
84MKINIT
85struct parsefile {
86	struct parsefile *prev;	/* preceding file on stack */
87	int linno;		/* current line */
88	int fd;			/* file descriptor (or -1 if string) */
89	int nleft;		/* number of chars left in this line */
90	int lleft;		/* number of lines left in this buffer */
91	char *nextc;		/* next char in buffer */
92	char *buf;		/* input buffer */
93	struct strpush *strpush; /* for pushing strings at this level */
94	struct strpush basestrpush; /* so pushing one is fast */
95};
96
97
98int plinno = 1;			/* input line number */
99MKINIT int parsenleft;		/* copy of parsefile->nleft */
100MKINIT int parselleft;		/* copy of parsefile->lleft */
101char *parsenextc;		/* copy of parsefile->nextc */
102MKINIT struct parsefile basepf;	/* top level input file */
103char basebuf[BUFSIZ];		/* buffer for top level input file */
104struct parsefile *parsefile = &basepf;	/* current input file */
105int init_editline = 0;		/* editline library initialized? */
106int whichprompt;		/* 1 == PS1, 2 == PS2 */
107
108EditLine *el;			/* cookie for editline package */
109
110STATIC void pushfile(void);
111static int preadfd(void);
112
113#ifdef mkinit
114INCLUDE "input.h"
115INCLUDE "error.h"
116
117INIT {
118	extern char basebuf[];
119
120	basepf.nextc = basepf.buf = basebuf;
121}
122
123RESET {
124	if (exception != EXSHELLPROC)
125		parselleft = parsenleft = 0;	/* clear input buffer */
126	popallfiles();
127}
128
129SHELLPROC {
130	popallfiles();
131}
132#endif
133
134
135/*
136 * Read a line from the script.
137 */
138
139char *
140pfgets(char *line, int len)
141{
142	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(void)
170{
171	return pgetc_macro();
172}
173
174
175static int
176preadfd(void)
177{
178	int nr;
179	parsenextc = parsefile->buf;
180
181retry:
182#ifndef NO_HISTORY
183	if (parsefile->fd == 0 && el) {
184		const char *rl_cp;
185
186		rl_cp = el_gets(el, &nr);
187		if (rl_cp == NULL)
188			nr = 0;
189		else {
190			/* XXX - BUFSIZE should redesign so not necessary */
191			(void) strcpy(parsenextc, rl_cp);
192		}
193	} else
194#endif
195		nr = read(parsefile->fd, parsenextc, BUFSIZ - 1);
196
197	if (nr <= 0) {
198                if (nr < 0) {
199                        if (errno == EINTR)
200                                goto retry;
201                        if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
202                                int flags = fcntl(0, F_GETFL, 0);
203                                if (flags >= 0 && flags & O_NONBLOCK) {
204                                        flags &=~ O_NONBLOCK;
205                                        if (fcntl(0, F_SETFL, flags) >= 0) {
206						out2str("sh: turning off NDELAY mode\n");
207                                                goto retry;
208                                        }
209                                }
210                        }
211                }
212                nr = -1;
213	}
214	return nr;
215}
216
217/*
218 * Refill the input buffer and return the next input character:
219 *
220 * 1) If a string was pushed back on the input, pop it;
221 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
222 *    from a string so we can't refill the buffer, return EOF.
223 * 3) If there is more in this buffer, use it else call read to fill it.
224 * 4) Process input up to the next newline, deleting nul characters.
225 */
226
227int
228preadbuffer(void)
229{
230	char *p, *q;
231	int more;
232	int something;
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 = preadfd()) == -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		HistEvent he;
294		INTOFF;
295		history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
296		    parsenextc);
297		INTON;
298	}
299#endif
300
301	if (vflag) {
302		out2str(parsenextc);
303		flushout(out2);
304	}
305
306	*q = savec;
307
308	return *parsenextc++;
309}
310
311/*
312 * Undo the last call to pgetc.  Only one character may be pushed back.
313 * PEOF may be pushed back.
314 */
315
316void
317pungetc(void)
318{
319	parsenleft++;
320	parsenextc--;
321}
322
323/*
324 * Push a string back onto the input at this current parsefile level.
325 * We handle aliases this way.
326 */
327void
328pushstring(char *s, int len, 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(void)
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(char *fname, int push)
376{
377	int fd;
378	int fd2;
379
380	INTOFF;
381	if ((fd = open(fname, O_RDONLY)) < 0)
382		error("Can't open %s: %s", fname, strerror(errno));
383	if (fd < 10) {
384		fd2 = copyfd(fd, 10);
385		close(fd);
386		if (fd2 < 0)
387			error("Out of file descriptors");
388		fd = fd2;
389	}
390	setinputfd(fd, push);
391	INTON;
392}
393
394
395/*
396 * Like setinputfile, but takes an open file descriptor.  Call this with
397 * interrupts off.
398 */
399
400void
401setinputfd(int fd, int push)
402{
403	(void)fcntl(fd, F_SETFD, FD_CLOEXEC);
404	if (push) {
405		pushfile();
406		parsefile->buf = ckmalloc(BUFSIZ);
407	}
408	if (parsefile->fd > 0)
409		close(parsefile->fd);
410	parsefile->fd = fd;
411	if (parsefile->buf == NULL)
412		parsefile->buf = ckmalloc(BUFSIZ);
413	parselleft = parsenleft = 0;
414	plinno = 1;
415}
416
417
418/*
419 * Like setinputfile, but takes input from a string.
420 */
421
422void
423setinputstring(char *string, int push)
424{
425	INTOFF;
426	if (push)
427		pushfile();
428	parsenextc = string;
429	parselleft = parsenleft = strlen(string);
430	parsefile->buf = NULL;
431	plinno = 1;
432	INTON;
433}
434
435
436
437/*
438 * To handle the "." command, a stack of input files is used.  Pushfile
439 * adds a new entry to the stack and popfile restores the previous level.
440 */
441
442STATIC void
443pushfile(void)
444{
445	struct parsefile *pf;
446
447	parsefile->nleft = parsenleft;
448	parsefile->lleft = parselleft;
449	parsefile->nextc = parsenextc;
450	parsefile->linno = plinno;
451	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
452	pf->prev = parsefile;
453	pf->fd = -1;
454	pf->strpush = NULL;
455	pf->basestrpush.prev = NULL;
456	parsefile = pf;
457}
458
459
460void
461popfile(void)
462{
463	struct parsefile *pf = parsefile;
464
465	INTOFF;
466	if (pf->fd >= 0)
467		close(pf->fd);
468	if (pf->buf)
469		ckfree(pf->buf);
470	while (pf->strpush)
471		popstring();
472	parsefile = pf->prev;
473	ckfree(pf);
474	parsenleft = parsefile->nleft;
475	parselleft = parsefile->lleft;
476	parsenextc = parsefile->nextc;
477	plinno = parsefile->linno;
478	INTON;
479}
480
481
482/*
483 * Return to top level.
484 */
485
486void
487popallfiles(void)
488{
489	while (parsefile != &basepf)
490		popfile();
491}
492
493
494
495/*
496 * Close the file(s) that the shell is reading commands from.  Called
497 * after a fork is done.
498 */
499
500void
501closescript(void)
502{
503	popallfiles();
504	if (parsefile->fd > 0) {
505		close(parsefile->fd);
506		parsefile->fd = 0;
507	}
508}
509