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