input.c revision 1.40 
1/*	$NetBSD: input.c,v 1.40 2007/02/15 12:02:59 rillig Exp $	*/
2
3/*-
4 * Copyright (c) 1991, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Kenneth Almquist.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <sys/cdefs.h>
36#ifndef lint
37#if 0
38static char sccsid[] = "@(#)input.c	8.3 (Berkeley) 6/9/95";
39#else
40__RCSID("$NetBSD: input.c,v 1.40 2007/02/15 12:02:59 rillig Exp $");
41#endif
42#endif /* not lint */
43
44#include <stdio.h>	/* defines BUFSIZ */
45#include <fcntl.h>
46#include <errno.h>
47#include <unistd.h>
48#include <stdlib.h>
49#include <string.h>
50
51/*
52 * This file implements the input routines used by the parser.
53 */
54
55#include "shell.h"
56#include "redir.h"
57#include "syntax.h"
58#include "input.h"
59#include "output.h"
60#include "options.h"
61#include "memalloc.h"
62#include "error.h"
63#include "alias.h"
64#include "parser.h"
65#include "myhistedit.h"
66
67#define EOF_NLEFT -99		/* value of parsenleft when EOF pushed back */
68
69MKINIT
70struct strpush {
71	struct strpush *prev;	/* preceding string on stack */
72	char *prevstring;
73	int prevnleft;
74	int prevlleft;
75	struct alias *ap;	/* if push was associated with an alias */
76};
77
78/*
79 * The parsefile structure pointed to by the global variable parsefile
80 * contains information about the current file being read.
81 */
82
83MKINIT
84struct parsefile {
85	struct parsefile *prev;	/* preceding file on stack */
86	int linno;		/* current line */
87	int fd;			/* file descriptor (or -1 if string) */
88	int nleft;		/* number of chars left in this line */
89	int lleft;		/* number of chars left in this buffer */
90	char *nextc;		/* next char in buffer */
91	char *buf;		/* input buffer */
92	struct strpush *strpush; /* for pushing strings at this level */
93	struct strpush basestrpush; /* so pushing one is fast */
94};
95
96
97int plinno = 1;			/* input line number */
98int parsenleft;			/* copy of parsefile->nleft */
99MKINIT int parselleft;		/* copy of parsefile->lleft */
100char *parsenextc;		/* copy of parsefile->nextc */
101MKINIT struct parsefile basepf;	/* top level input file */
102MKINIT char basebuf[BUFSIZ];	/* buffer for top level input file */
103struct parsefile *parsefile = &basepf;	/* current input file */
104int init_editline = 0;		/* editline library initialized? */
105int whichprompt;		/* 1 == PS1, 2 == PS2 */
106
107EditLine *el;			/* cookie for editline package */
108
109STATIC void pushfile(void);
110static int preadfd(void);
111
112#ifdef mkinit
113INCLUDE <stdio.h>
114INCLUDE "input.h"
115INCLUDE "error.h"
116
117INIT {
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(char *line, int len)
139{
140	char *p = line;
141	int nleft = len;
142	int c;
143
144	while (--nleft > 0) {
145		c = pgetc_macro();
146		if (c == PEOF) {
147			if (p == line)
148				return NULL;
149			break;
150		}
151		*p++ = c;
152		if (c == '\n')
153			break;
154	}
155	*p = '\0';
156	return line;
157}
158
159
160
161/*
162 * Read a character from the script, returning PEOF on end of file.
163 * Nul characters in the input are silently discarded.
164 */
165
166int
167pgetc(void)
168{
169	return pgetc_macro();
170}
171
172
173static int
174preadfd(void)
175{
176	int nr;
177	char *buf =  parsefile->buf;
178	parsenextc = buf;
179
180retry:
181#ifndef SMALL
182	if (parsefile->fd == 0 && el) {
183		static const char *rl_cp;
184		static int el_len;
185
186		if (rl_cp == NULL)
187			rl_cp = el_gets(el, &el_len);
188		if (rl_cp == NULL)
189			nr = 0;
190		else {
191			nr = el_len;
192			if (nr > BUFSIZ - 8)
193				nr = BUFSIZ - 8;
194			memcpy(buf, rl_cp, nr);
195			if (nr != el_len) {
196				el_len -= nr;
197				rl_cp += nr;
198			} else
199				rl_cp = 0;
200		}
201
202	} else
203#endif
204		nr = read(parsefile->fd, buf, BUFSIZ - 8);
205
206
207	if (nr <= 0) {
208                if (nr < 0) {
209                        if (errno == EINTR)
210                                goto retry;
211                        if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
212                                int flags = fcntl(0, F_GETFL, 0);
213                                if (flags >= 0 && flags & O_NONBLOCK) {
214                                        flags &=~ O_NONBLOCK;
215                                        if (fcntl(0, F_SETFL, flags) >= 0) {
216						out2str("sh: turning off NDELAY mode\n");
217                                                goto retry;
218                                        }
219                                }
220                        }
221                }
222                nr = -1;
223	}
224	return nr;
225}
226
227/*
228 * Refill the input buffer and return the next input character:
229 *
230 * 1) If a string was pushed back on the input, pop it;
231 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
232 *    from a string so we can't refill the buffer, return EOF.
233 * 3) If the is more stuff in this buffer, use it else call read to fill it.
234 * 4) Process input up to the next newline, deleting nul characters.
235 */
236
237int
238preadbuffer(void)
239{
240	char *p, *q;
241	int more;
242	int something;
243	char savec;
244
245	if (parsefile->strpush) {
246		popstring();
247		if (--parsenleft >= 0)
248			return (*parsenextc++);
249	}
250	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
251		return PEOF;
252	flushout(&output);
253	flushout(&errout);
254
255again:
256	if (parselleft <= 0) {
257		if ((parselleft = preadfd()) == -1) {
258			parselleft = parsenleft = EOF_NLEFT;
259			return PEOF;
260		}
261	}
262
263	q = p = parsenextc;
264
265	/* delete nul characters */
266	something = 0;
267	for (more = 1; more;) {
268		switch (*p) {
269		case '\0':
270			p++;	/* Skip nul */
271			goto check;
272
273		case '\t':
274		case ' ':
275			break;
276
277		case '\n':
278			parsenleft = q - parsenextc;
279			more = 0; /* Stop processing here */
280			break;
281
282		default:
283			something = 1;
284			break;
285		}
286
287		*q++ = *p++;
288check:
289		if (--parselleft <= 0) {
290			parsenleft = q - parsenextc - 1;
291			if (parsenleft < 0)
292				goto again;
293			*q = '\0';
294			more = 0;
295		}
296	}
297
298	savec = *q;
299	*q = '\0';
300
301#ifndef SMALL
302	if (parsefile->fd == 0 && hist && something) {
303		HistEvent he;
304		INTOFF;
305		history(hist, &he, whichprompt == 1? H_ENTER : H_APPEND,
306		    parsenextc);
307		INTON;
308	}
309#endif
310
311	if (vflag) {
312		out2str(parsenextc);
313		flushout(out2);
314	}
315
316	*q = savec;
317
318	return *parsenextc++;
319}
320
321/*
322 * Undo the last call to pgetc.  Only one character may be pushed back.
323 * PEOF may be pushed back.
324 */
325
326void
327pungetc(void)
328{
329	parsenleft++;
330	parsenextc--;
331}
332
333/*
334 * Push a string back onto the input at this current parsefile level.
335 * We handle aliases this way.
336 */
337void
338pushstring(char *s, int len, void *ap)
339{
340	struct strpush *sp;
341
342	INTOFF;
343/*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
344	if (parsefile->strpush) {
345		sp = ckmalloc(sizeof (struct strpush));
346		sp->prev = parsefile->strpush;
347		parsefile->strpush = sp;
348	} else
349		sp = parsefile->strpush = &(parsefile->basestrpush);
350	sp->prevstring = parsenextc;
351	sp->prevnleft = parsenleft;
352	sp->prevlleft = parselleft;
353	sp->ap = (struct alias *)ap;
354	if (ap)
355		((struct alias *)ap)->flag |= ALIASINUSE;
356	parsenextc = s;
357	parsenleft = len;
358	INTON;
359}
360
361void
362popstring(void)
363{
364	struct strpush *sp = parsefile->strpush;
365
366	INTOFF;
367	parsenextc = sp->prevstring;
368	parsenleft = sp->prevnleft;
369	parselleft = sp->prevlleft;
370/*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
371	if (sp->ap)
372		sp->ap->flag &= ~ALIASINUSE;
373	parsefile->strpush = sp->prev;
374	if (sp != &(parsefile->basestrpush))
375		ckfree(sp);
376	INTON;
377}
378
379/*
380 * Set the input to take input from a file.  If push is set, push the
381 * old input onto the stack first.
382 */
383
384void
385setinputfile(const char *fname, int push)
386{
387	unsigned char magic[4];
388	int fd;
389	int fd2;
390
391	INTOFF;
392	if ((fd = open(fname, O_RDONLY)) < 0)
393		error("Can't open %s", fname);
394
395	/* Since the message "Syntax error: "(" unexpected" is not very
396	 * helpful, we check if the file starts with the ELF magic to
397	 * avoid that message. The first lseek tries to make sure that
398	 * we can later rewind the file.
399	 */
400	if (lseek(fd, 0, SEEK_SET) == 0) {
401		if (read(fd, magic, 4) == 4) {
402			if (memcmp(magic, "\177ELF", 4) == 0)
403				error("Cannot execute ELF binary %s", fname);
404		}
405		if (lseek(fd, 0, SEEK_SET) != 0)
406			error("Cannot rewind the file %s", fname);
407	}
408
409	if (fd < 10) {
410		fd2 = copyfd(fd, 10);
411		close(fd);
412		if (fd2 < 0)
413			error("Out of file descriptors");
414		fd = fd2;
415	}
416	setinputfd(fd, push);
417	INTON;
418}
419
420
421/*
422 * Like setinputfile, but takes an open file descriptor.  Call this with
423 * interrupts off.
424 */
425
426void
427setinputfd(int fd, int push)
428{
429	(void) fcntl(fd, F_SETFD, FD_CLOEXEC);
430	if (push) {
431		pushfile();
432		parsefile->buf = ckmalloc(BUFSIZ);
433	}
434	if (parsefile->fd > 0)
435		close(parsefile->fd);
436	parsefile->fd = fd;
437	if (parsefile->buf == NULL)
438		parsefile->buf = ckmalloc(BUFSIZ);
439	parselleft = parsenleft = 0;
440	plinno = 1;
441}
442
443
444/*
445 * Like setinputfile, but takes input from a string.
446 */
447
448void
449setinputstring(char *string, int push)
450{
451	INTOFF;
452	if (push)
453		pushfile();
454	parsenextc = string;
455	parselleft = parsenleft = strlen(string);
456	parsefile->buf = NULL;
457	plinno = 1;
458	INTON;
459}
460
461
462
463/*
464 * To handle the "." command, a stack of input files is used.  Pushfile
465 * adds a new entry to the stack and popfile restores the previous level.
466 */
467
468STATIC void
469pushfile(void)
470{
471	struct parsefile *pf;
472
473	parsefile->nleft = parsenleft;
474	parsefile->lleft = parselleft;
475	parsefile->nextc = parsenextc;
476	parsefile->linno = plinno;
477	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
478	pf->prev = parsefile;
479	pf->fd = -1;
480	pf->strpush = NULL;
481	pf->basestrpush.prev = NULL;
482	parsefile = pf;
483}
484
485
486void
487popfile(void)
488{
489	struct parsefile *pf = parsefile;
490
491	INTOFF;
492	if (pf->fd >= 0)
493		close(pf->fd);
494	if (pf->buf)
495		ckfree(pf->buf);
496	while (pf->strpush)
497		popstring();
498	parsefile = pf->prev;
499	ckfree(pf);
500	parsenleft = parsefile->nleft;
501	parselleft = parsefile->lleft;
502	parsenextc = parsefile->nextc;
503	plinno = parsefile->linno;
504	INTON;
505}
506
507
508/*
509 * Return to top level.
510 */
511
512void
513popallfiles(void)
514{
515	while (parsefile != &basepf)
516		popfile();
517}
518
519
520
521/*
522 * Close the file(s) that the shell is reading commands from.  Called
523 * after a fork is done.
524 *
525 * Takes one arg, vfork, which tells it to not modify its global vars
526 * as it is still running in the parent.
527 *
528 * This code is (probably) unnecessary as the 'close on exec' flag is
529 * set and should be enough.  In the vfork case it is definitely wrong
530 * to close the fds as another fork() may be done later to feed data
531 * from a 'here' document into a pipe and we don't want to close the
532 * pipe!
533 */
534
535void
536closescript(int vforked)
537{
538	if (vforked)
539		return;
540	popallfiles();
541	if (parsefile->fd > 0) {
542		close(parsefile->fd);
543		parsefile->fd = 0;
544	}
545}
546