input.c revision 127958 
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 127958 2004-04-06 20:06:54Z markm $");
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 */
96MKINIT int 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
114INIT {
115	extern char basebuf[];
116
117	basepf.nextc = basepf.buf = basebuf;
118}
119
120RESET {
121	if (exception != EXSHELLPROC)
122		parselleft = parsenleft = 0;	/* clear input buffer */
123	popallfiles();
124}
125
126SHELLPROC {
127	popallfiles();
128}
129#endif
130
131
132/*
133 * Read a line from the script.
134 */
135
136char *
137pfgets(char *line, int len)
138{
139	char *p = line;
140	int nleft = len;
141	int c;
142
143	while (--nleft > 0) {
144		c = pgetc_macro();
145		if (c == PEOF) {
146			if (p == line)
147				return NULL;
148			break;
149		}
150		*p++ = c;
151		if (c == '\n')
152			break;
153	}
154	*p = '\0';
155	return line;
156}
157
158
159
160/*
161 * Read a character from the script, returning PEOF on end of file.
162 * Nul characters in the input are silently discarded.
163 */
164
165int
166pgetc(void)
167{
168	return pgetc_macro();
169}
170
171
172static int
173preadfd(void)
174{
175	int nr;
176	parsenextc = parsefile->buf;
177
178#ifndef NO_HISTORY
179	if (el != NULL && gotwinch) {
180		gotwinch = 0;
181		el_resize(el);
182	}
183#endif
184retry:
185#ifndef NO_HISTORY
186	if (parsefile->fd == 0 && el) {
187		const char *rl_cp;
188
189		rl_cp = el_gets(el, &nr);
190		if (rl_cp == NULL)
191			nr = 0;
192		else {
193			/* XXX - BUFSIZE should redesign so not necessary */
194			(void) strcpy(parsenextc, rl_cp);
195		}
196	} else
197#endif
198		nr = read(parsefile->fd, parsenextc, BUFSIZ - 1);
199
200	if (nr <= 0) {
201                if (nr < 0) {
202                        if (errno == EINTR)
203                                goto retry;
204                        if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
205                                int flags = fcntl(0, F_GETFL, 0);
206                                if (flags >= 0 && flags & O_NONBLOCK) {
207                                        flags &=~ O_NONBLOCK;
208                                        if (fcntl(0, F_SETFL, flags) >= 0) {
209						out2str("sh: turning off NDELAY mode\n");
210                                                goto retry;
211                                        }
212                                }
213                        }
214                }
215                nr = -1;
216	}
217	return nr;
218}
219
220/*
221 * Refill the input buffer and return the next input character:
222 *
223 * 1) If a string was pushed back on the input, pop it;
224 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
225 *    from a string so we can't refill the buffer, return EOF.
226 * 3) If there is more in this buffer, use it else call read to fill it.
227 * 4) Process input up to the next newline, deleting nul characters.
228 */
229
230int
231preadbuffer(void)
232{
233	char *p, *q;
234	int more;
235	int something;
236	char savec;
237
238	if (parsefile->strpush) {
239		popstring();
240		if (--parsenleft >= 0)
241			return (*parsenextc++);
242	}
243	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
244		return PEOF;
245	flushout(&output);
246	flushout(&errout);
247
248again:
249	if (parselleft <= 0) {
250		if ((parselleft = preadfd()) == -1) {
251			parselleft = parsenleft = EOF_NLEFT;
252			return PEOF;
253		}
254	}
255
256	q = p = parsenextc;
257
258	/* delete nul characters */
259	something = 0;
260	for (more = 1; more;) {
261		switch (*p) {
262		case '\0':
263			p++;	/* Skip nul */
264			goto check;
265
266		case '\t':
267		case ' ':
268			break;
269
270		case '\n':
271			parsenleft = q - parsenextc;
272			more = 0; /* Stop processing here */
273			break;
274
275		default:
276			something = 1;
277			break;
278		}
279
280		*q++ = *p++;
281check:
282		if (--parselleft <= 0) {
283			parsenleft = q - parsenextc - 1;
284			if (parsenleft < 0)
285				goto again;
286			*q = '\0';
287			more = 0;
288		}
289	}
290
291	savec = *q;
292	*q = '\0';
293
294#ifndef NO_HISTORY
295	if (parsefile->fd == 0 && hist && something) {
296		HistEvent he;
297		INTOFF;
298		history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
299		    parsenextc);
300		INTON;
301	}
302#endif
303
304	if (vflag) {
305		out2str(parsenextc);
306		flushout(out2);
307	}
308
309	*q = savec;
310
311	return *parsenextc++;
312}
313
314/*
315 * Undo the last call to pgetc.  Only one character may be pushed back.
316 * PEOF may be pushed back.
317 */
318
319void
320pungetc(void)
321{
322	parsenleft++;
323	parsenextc--;
324}
325
326/*
327 * Push a string back onto the input at this current parsefile level.
328 * We handle aliases this way.
329 */
330void
331pushstring(char *s, int len, void *ap)
332{
333	struct strpush *sp;
334
335	INTOFF;
336/*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
337	if (parsefile->strpush) {
338		sp = ckmalloc(sizeof (struct strpush));
339		sp->prev = parsefile->strpush;
340		parsefile->strpush = sp;
341	} else
342		sp = parsefile->strpush = &(parsefile->basestrpush);
343	sp->prevstring = parsenextc;
344	sp->prevnleft = parsenleft;
345	sp->prevlleft = parselleft;
346	sp->ap = (struct alias *)ap;
347	if (ap)
348		((struct alias *)ap)->flag |= ALIASINUSE;
349	parsenextc = s;
350	parsenleft = len;
351	INTON;
352}
353
354void
355popstring(void)
356{
357	struct strpush *sp = parsefile->strpush;
358
359	INTOFF;
360	parsenextc = sp->prevstring;
361	parsenleft = sp->prevnleft;
362	parselleft = sp->prevlleft;
363/*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
364	if (sp->ap)
365		sp->ap->flag &= ~ALIASINUSE;
366	parsefile->strpush = sp->prev;
367	if (sp != &(parsefile->basestrpush))
368		ckfree(sp);
369	INTON;
370}
371
372/*
373 * Set the input to take input from a file.  If push is set, push the
374 * old input onto the stack first.
375 */
376
377void
378setinputfile(char *fname, int push)
379{
380	int fd;
381	int fd2;
382
383	INTOFF;
384	if ((fd = open(fname, O_RDONLY)) < 0)
385		error("Can't open %s: %s", fname, strerror(errno));
386	if (fd < 10) {
387		fd2 = fcntl(fd, F_DUPFD, 10);
388		close(fd);
389		if (fd2 < 0)
390			error("Out of file descriptors");
391		fd = fd2;
392	}
393	setinputfd(fd, push);
394	INTON;
395}
396
397
398/*
399 * Like setinputfile, but takes an open file descriptor.  Call this with
400 * interrupts off.
401 */
402
403void
404setinputfd(int fd, int push)
405{
406	(void)fcntl(fd, F_SETFD, FD_CLOEXEC);
407	if (push) {
408		pushfile();
409		parsefile->buf = ckmalloc(BUFSIZ);
410	}
411	if (parsefile->fd > 0)
412		close(parsefile->fd);
413	parsefile->fd = fd;
414	if (parsefile->buf == NULL)
415		parsefile->buf = ckmalloc(BUFSIZ);
416	parselleft = parsenleft = 0;
417	plinno = 1;
418}
419
420
421/*
422 * Like setinputfile, but takes input from a string.
423 */
424
425void
426setinputstring(char *string, int push)
427{
428	INTOFF;
429	if (push)
430		pushfile();
431	parsenextc = string;
432	parselleft = parsenleft = strlen(string);
433	parsefile->buf = NULL;
434	plinno = 1;
435	INTON;
436}
437
438
439
440/*
441 * To handle the "." command, a stack of input files is used.  Pushfile
442 * adds a new entry to the stack and popfile restores the previous level.
443 */
444
445STATIC void
446pushfile(void)
447{
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(void)
465{
466	struct parsefile *pf = parsefile;
467
468	INTOFF;
469	if (pf->fd >= 0)
470		close(pf->fd);
471	if (pf->buf)
472		ckfree(pf->buf);
473	while (pf->strpush)
474		popstring();
475	parsefile = pf->prev;
476	ckfree(pf);
477	parsenleft = parsefile->nleft;
478	parselleft = parsefile->lleft;
479	parsenextc = parsefile->nextc;
480	plinno = parsefile->linno;
481	INTON;
482}
483
484
485/*
486 * Return to top level.
487 */
488
489void
490popallfiles(void)
491{
492	while (parsefile != &basepf)
493		popfile();
494}
495
496
497
498/*
499 * Close the file(s) that the shell is reading commands from.  Called
500 * after a fork is done.
501 */
502
503void
504closescript(void)
505{
506	popallfiles();
507	if (parsefile->fd > 0) {
508		close(parsefile->fd);
509		parsefile->fd = 0;
510	}
511}
512