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input.c revision 1.36 
      1 /*	$NetBSD: input.c,v 1.36 2002/09/27 18:56:52 christos 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. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #ifndef lint
     41 #if 0
     42 static char sccsid[] = "@(#)input.c	8.3 (Berkeley) 6/9/95";
     43 #else
     44 __RCSID("$NetBSD: input.c,v 1.36 2002/09/27 18:56:52 christos Exp $");
     45 #endif
     46 #endif /* not lint */
     47 
     48 #include <stdio.h>	/* defines BUFSIZ */
     49 #include <fcntl.h>
     50 #include <errno.h>
     51 #include <unistd.h>
     52 #include <stdlib.h>
     53 #include <string.h>
     54 
     55 /*
     56  * This file implements the input routines used by the parser.
     57  */
     58 
     59 #include "shell.h"
     60 #include "redir.h"
     61 #include "syntax.h"
     62 #include "input.h"
     63 #include "output.h"
     64 #include "options.h"
     65 #include "memalloc.h"
     66 #include "error.h"
     67 #include "alias.h"
     68 #include "parser.h"
     69 #include "myhistedit.h"
     70 
     71 #define EOF_NLEFT -99		/* value of parsenleft when EOF pushed back */
     72 
     73 MKINIT
     74 struct strpush {
     75 	struct strpush *prev;	/* preceding string on stack */
     76 	char *prevstring;
     77 	int prevnleft;
     78 	int prevlleft;
     79 	struct alias *ap;	/* if push was associated with an alias */
     80 };
     81 
     82 /*
     83  * The parsefile structure pointed to by the global variable parsefile
     84  * contains information about the current file being read.
     85  */
     86 
     87 MKINIT
     88 struct parsefile {
     89 	struct parsefile *prev;	/* preceding file on stack */
     90 	int linno;		/* current line */
     91 	int fd;			/* file descriptor (or -1 if string) */
     92 	int nleft;		/* number of chars left in this line */
     93 	int lleft;		/* number of chars left in this buffer */
     94 	char *nextc;		/* next char in buffer */
     95 	char *buf;		/* input buffer */
     96 	struct strpush *strpush; /* for pushing strings at this level */
     97 	struct strpush basestrpush; /* so pushing one is fast */
     98 };
     99 
    100 
    101 int plinno = 1;			/* input line number */
    102 int parsenleft;			/* copy of parsefile->nleft */
    103 MKINIT int parselleft;		/* copy of parsefile->lleft */
    104 char *parsenextc;		/* copy of parsefile->nextc */
    105 MKINIT struct parsefile basepf;	/* top level input file */
    106 MKINIT char basebuf[BUFSIZ];	/* buffer for top level input file */
    107 struct parsefile *parsefile = &basepf;	/* current input file */
    108 int init_editline = 0;		/* editline library initialized? */
    109 int whichprompt;		/* 1 == PS1, 2 == PS2 */
    110 
    111 EditLine *el;			/* cookie for editline package */
    112 
    113 STATIC void pushfile __P((void));
    114 static int preadfd __P((void));
    115 
    116 #ifdef mkinit
    117 INCLUDE <stdio.h>
    118 INCLUDE "input.h"
    119 INCLUDE "error.h"
    120 
    121 INIT {
    122 	basepf.nextc = basepf.buf = basebuf;
    123 }
    124 
    125 RESET {
    126 	if (exception != EXSHELLPROC)
    127 		parselleft = parsenleft = 0;	/* clear input buffer */
    128 	popallfiles();
    129 }
    130 
    131 SHELLPROC {
    132 	popallfiles();
    133 }
    134 #endif
    135 
    136 
    137 /*
    138  * Read a line from the script.
    139  */
    140 
    141 char *
    142 pfgets(line, len)
    143 	char *line;
    144 	int len;
    145 {
    146 	char *p = line;
    147 	int nleft = len;
    148 	int c;
    149 
    150 	while (--nleft > 0) {
    151 		c = pgetc_macro();
    152 		if (c == PEOF) {
    153 			if (p == line)
    154 				return NULL;
    155 			break;
    156 		}
    157 		*p++ = c;
    158 		if (c == '\n')
    159 			break;
    160 	}
    161 	*p = '\0';
    162 	return line;
    163 }
    164 
    165 
    166 
    167 /*
    168  * Read a character from the script, returning PEOF on end of file.
    169  * Nul characters in the input are silently discarded.
    170  */
    171 
    172 int
    173 pgetc()
    174 {
    175 	return pgetc_macro();
    176 }
    177 
    178 
    179 static int
    180 preadfd()
    181 {
    182 	int nr;
    183 	char *buf =  parsefile->buf;
    184 	parsenextc = buf;
    185 
    186 retry:
    187 #ifndef SMALL
    188 	if (parsefile->fd == 0 && el) {
    189 		const char *rl_cp;
    190 
    191 		rl_cp = el_gets(el, &nr);
    192 		if (rl_cp == NULL)
    193 			nr = 0;
    194 		else {
    195 			/* XXX - BUFSIZE should redesign so not necessary */
    196 			(void) strcpy(buf, rl_cp);
    197 		}
    198 	} else
    199 #endif
    200 		nr = read(parsefile->fd, buf, BUFSIZ - 1);
    201 
    202 
    203 	if (nr <= 0) {
    204                 if (nr < 0) {
    205                         if (errno == EINTR)
    206                                 goto retry;
    207                         if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
    208                                 int flags = fcntl(0, F_GETFL, 0);
    209                                 if (flags >= 0 && flags & O_NONBLOCK) {
    210                                         flags &=~ O_NONBLOCK;
    211                                         if (fcntl(0, F_SETFL, flags) >= 0) {
    212 						out2str("sh: turning off NDELAY mode\n");
    213                                                 goto retry;
    214                                         }
    215                                 }
    216                         }
    217                 }
    218                 nr = -1;
    219 	}
    220 	return nr;
    221 }
    222 
    223 /*
    224  * Refill the input buffer and return the next input character:
    225  *
    226  * 1) If a string was pushed back on the input, pop it;
    227  * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
    228  *    from a string so we can't refill the buffer, return EOF.
    229  * 3) If the is more stuff in this buffer, use it else call read to fill it.
    230  * 4) Process input up to the next newline, deleting nul characters.
    231  */
    232 
    233 int
    234 preadbuffer()
    235 {
    236 	char *p, *q;
    237 	int more;
    238 	int something;
    239 	char savec;
    240 
    241 	if (parsefile->strpush) {
    242 		popstring();
    243 		if (--parsenleft >= 0)
    244 			return (*parsenextc++);
    245 	}
    246 	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
    247 		return PEOF;
    248 	flushout(&output);
    249 	flushout(&errout);
    250 
    251 again:
    252 	if (parselleft <= 0) {
    253 		if ((parselleft = preadfd()) == -1) {
    254 			parselleft = parsenleft = EOF_NLEFT;
    255 			return PEOF;
    256 		}
    257 	}
    258 
    259 	q = p = parsenextc;
    260 
    261 	/* delete nul characters */
    262 	something = 0;
    263 	for (more = 1; more;) {
    264 		switch (*p) {
    265 		case '\0':
    266 			p++;	/* Skip nul */
    267 			goto check;
    268 
    269 		case '\t':
    270 		case ' ':
    271 			break;
    272 
    273 		case '\n':
    274 			parsenleft = q - parsenextc;
    275 			more = 0; /* Stop processing here */
    276 			break;
    277 
    278 		default:
    279 			something = 1;
    280 			break;
    281 		}
    282 
    283 		*q++ = *p++;
    284 check:
    285 		if (--parselleft <= 0) {
    286 			parsenleft = q - parsenextc - 1;
    287 			if (parsenleft < 0)
    288 				goto again;
    289 			*q = '\0';
    290 			more = 0;
    291 		}
    292 	}
    293 
    294 	savec = *q;
    295 	*q = '\0';
    296 
    297 #ifndef SMALL
    298 	if (parsefile->fd == 0 && hist && something) {
    299 		HistEvent he;
    300 		INTOFF;
    301 		history(hist, &he, whichprompt == 1? H_ENTER : H_APPEND,
    302 		    parsenextc);
    303 		INTON;
    304 	}
    305 #endif
    306 
    307 	if (vflag) {
    308 		out2str(parsenextc);
    309 		flushout(out2);
    310 	}
    311 
    312 	*q = savec;
    313 
    314 	return *parsenextc++;
    315 }
    316 
    317 /*
    318  * Undo the last call to pgetc.  Only one character may be pushed back.
    319  * PEOF may be pushed back.
    320  */
    321 
    322 void
    323 pungetc() {
    324 	parsenleft++;
    325 	parsenextc--;
    326 }
    327 
    328 /*
    329  * Push a string back onto the input at this current parsefile level.
    330  * We handle aliases this way.
    331  */
    332 void
    333 pushstring(s, len, ap)
    334 	char *s;
    335 	int len;
    336 	void *ap;
    337 	{
    338 	struct strpush *sp;
    339 
    340 	INTOFF;
    341 /*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
    342 	if (parsefile->strpush) {
    343 		sp = ckmalloc(sizeof (struct strpush));
    344 		sp->prev = parsefile->strpush;
    345 		parsefile->strpush = sp;
    346 	} else
    347 		sp = parsefile->strpush = &(parsefile->basestrpush);
    348 	sp->prevstring = parsenextc;
    349 	sp->prevnleft = parsenleft;
    350 	sp->prevlleft = parselleft;
    351 	sp->ap = (struct alias *)ap;
    352 	if (ap)
    353 		((struct alias *)ap)->flag |= ALIASINUSE;
    354 	parsenextc = s;
    355 	parsenleft = len;
    356 	INTON;
    357 }
    358 
    359 void
    360 popstring()
    361 {
    362 	struct strpush *sp = parsefile->strpush;
    363 
    364 	INTOFF;
    365 	parsenextc = sp->prevstring;
    366 	parsenleft = sp->prevnleft;
    367 	parselleft = sp->prevlleft;
    368 /*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
    369 	if (sp->ap)
    370 		sp->ap->flag &= ~ALIASINUSE;
    371 	parsefile->strpush = sp->prev;
    372 	if (sp != &(parsefile->basestrpush))
    373 		ckfree(sp);
    374 	INTON;
    375 }
    376 
    377 /*
    378  * Set the input to take input from a file.  If push is set, push the
    379  * old input onto the stack first.
    380  */
    381 
    382 void
    383 setinputfile(fname, push)
    384 	const char *fname;
    385 	int push;
    386 {
    387 	int fd;
    388 	int fd2;
    389 
    390 	INTOFF;
    391 	if ((fd = open(fname, O_RDONLY)) < 0)
    392 		error("Can't open %s", fname);
    393 	if (fd < 10) {
    394 		fd2 = copyfd(fd, 10);
    395 		close(fd);
    396 		if (fd2 < 0)
    397 			error("Out of file descriptors");
    398 		fd = fd2;
    399 	}
    400 	setinputfd(fd, push);
    401 	INTON;
    402 }
    403 
    404 
    405 /*
    406  * Like setinputfile, but takes an open file descriptor.  Call this with
    407  * interrupts off.
    408  */
    409 
    410 void
    411 setinputfd(fd, push)
    412 	int fd, push;
    413 {
    414 	(void) fcntl(fd, F_SETFD, FD_CLOEXEC);
    415 	if (push) {
    416 		pushfile();
    417 		parsefile->buf = ckmalloc(BUFSIZ);
    418 	}
    419 	if (parsefile->fd > 0)
    420 		close(parsefile->fd);
    421 	parsefile->fd = fd;
    422 	if (parsefile->buf == NULL)
    423 		parsefile->buf = ckmalloc(BUFSIZ);
    424 	parselleft = parsenleft = 0;
    425 	plinno = 1;
    426 }
    427 
    428 
    429 /*
    430  * Like setinputfile, but takes input from a string.
    431  */
    432 
    433 void
    434 setinputstring(string, push)
    435 	char *string;
    436 	int push;
    437 	{
    438 	INTOFF;
    439 	if (push)
    440 		pushfile();
    441 	parsenextc = string;
    442 	parselleft = parsenleft = strlen(string);
    443 	parsefile->buf = NULL;
    444 	plinno = 1;
    445 	INTON;
    446 }
    447 
    448 
    449 
    450 /*
    451  * To handle the "." command, a stack of input files is used.  Pushfile
    452  * adds a new entry to the stack and popfile restores the previous level.
    453  */
    454 
    455 STATIC void
    456 pushfile() {
    457 	struct parsefile *pf;
    458 
    459 	parsefile->nleft = parsenleft;
    460 	parsefile->lleft = parselleft;
    461 	parsefile->nextc = parsenextc;
    462 	parsefile->linno = plinno;
    463 	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
    464 	pf->prev = parsefile;
    465 	pf->fd = -1;
    466 	pf->strpush = NULL;
    467 	pf->basestrpush.prev = NULL;
    468 	parsefile = pf;
    469 }
    470 
    471 
    472 void
    473 popfile() {
    474 	struct parsefile *pf = parsefile;
    475 
    476 	INTOFF;
    477 	if (pf->fd >= 0)
    478 		close(pf->fd);
    479 	if (pf->buf)
    480 		ckfree(pf->buf);
    481 	while (pf->strpush)
    482 		popstring();
    483 	parsefile = pf->prev;
    484 	ckfree(pf);
    485 	parsenleft = parsefile->nleft;
    486 	parselleft = parsefile->lleft;
    487 	parsenextc = parsefile->nextc;
    488 	plinno = parsefile->linno;
    489 	INTON;
    490 }
    491 
    492 
    493 /*
    494  * Return to top level.
    495  */
    496 
    497 void
    498 popallfiles() {
    499 	while (parsefile != &basepf)
    500 		popfile();
    501 }
    502 
    503 
    504 
    505 /*
    506  * Close the file(s) that the shell is reading commands from.  Called
    507  * after a fork is done.
    508  *
    509  * Takes one arg, vfork, which tells it to not modify its global vars
    510  * as it is still running in the parent.
    511  */
    512 
    513 void
    514 closescript(int vforked) {
    515 	if (vforked) {
    516 		struct parsefile *pf;
    517 
    518 		for (pf=parsefile; pf != &basepf; pf=pf->prev)
    519 			close(pf->fd);
    520 		if (parsefile->fd > 0)
    521 			close(parsefile->fd);
    522 		return;
    523 	}
    524 	popallfiles();
    525 	if (parsefile->fd > 0) {
    526 		close(parsefile->fd);
    527 		parsefile->fd = 0;
    528 	}
    529 }
    530