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input.c revision 1.38 
      1 /*	$NetBSD: input.c,v 1.38 2003/05/15 13:26:45 dsl 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 1.38 2003/05/15 13:26:45 dsl 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(void);
    114 static int preadfd(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(char *line, int len)
    143 {
    144 	char *p = line;
    145 	int nleft = len;
    146 	int c;
    147 
    148 	while (--nleft > 0) {
    149 		c = pgetc_macro();
    150 		if (c == PEOF) {
    151 			if (p == line)
    152 				return NULL;
    153 			break;
    154 		}
    155 		*p++ = c;
    156 		if (c == '\n')
    157 			break;
    158 	}
    159 	*p = '\0';
    160 	return line;
    161 }
    162 
    163 
    164 
    165 /*
    166  * Read a character from the script, returning PEOF on end of file.
    167  * Nul characters in the input are silently discarded.
    168  */
    169 
    170 int
    171 pgetc(void)
    172 {
    173 	return pgetc_macro();
    174 }
    175 
    176 
    177 static int
    178 preadfd(void)
    179 {
    180 	int nr;
    181 	char *buf =  parsefile->buf;
    182 	parsenextc = buf;
    183 
    184 retry:
    185 #ifndef SMALL
    186 	if (parsefile->fd == 0 && el) {
    187 		static const char *rl_cp;
    188 		static int el_len;
    189 
    190 		if (rl_cp == NULL)
    191 			rl_cp = el_gets(el, &el_len);
    192 		if (rl_cp == NULL)
    193 			nr = 0;
    194 		else {
    195 			nr = el_len;
    196 			if (nr > BUFSIZ - 8)
    197 				nr = BUFSIZ - 8;
    198 			memcpy(buf, rl_cp, nr);
    199 			if (nr != el_len) {
    200 				el_len -= nr;
    201 				rl_cp += nr;
    202 			} else
    203 				rl_cp = 0;
    204 		}
    205 
    206 	} else
    207 #endif
    208 		nr = read(parsefile->fd, buf, BUFSIZ - 8);
    209 
    210 
    211 	if (nr <= 0) {
    212                 if (nr < 0) {
    213                         if (errno == EINTR)
    214                                 goto retry;
    215                         if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
    216                                 int flags = fcntl(0, F_GETFL, 0);
    217                                 if (flags >= 0 && flags & O_NONBLOCK) {
    218                                         flags &=~ O_NONBLOCK;
    219                                         if (fcntl(0, F_SETFL, flags) >= 0) {
    220 						out2str("sh: turning off NDELAY mode\n");
    221                                                 goto retry;
    222                                         }
    223                                 }
    224                         }
    225                 }
    226                 nr = -1;
    227 	}
    228 	return nr;
    229 }
    230 
    231 /*
    232  * Refill the input buffer and return the next input character:
    233  *
    234  * 1) If a string was pushed back on the input, pop it;
    235  * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
    236  *    from a string so we can't refill the buffer, return EOF.
    237  * 3) If the is more stuff in this buffer, use it else call read to fill it.
    238  * 4) Process input up to the next newline, deleting nul characters.
    239  */
    240 
    241 int
    242 preadbuffer(void)
    243 {
    244 	char *p, *q;
    245 	int more;
    246 	int something;
    247 	char savec;
    248 
    249 	if (parsefile->strpush) {
    250 		popstring();
    251 		if (--parsenleft >= 0)
    252 			return (*parsenextc++);
    253 	}
    254 	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
    255 		return PEOF;
    256 	flushout(&output);
    257 	flushout(&errout);
    258 
    259 again:
    260 	if (parselleft <= 0) {
    261 		if ((parselleft = preadfd()) == -1) {
    262 			parselleft = parsenleft = EOF_NLEFT;
    263 			return PEOF;
    264 		}
    265 	}
    266 
    267 	q = p = parsenextc;
    268 
    269 	/* delete nul characters */
    270 	something = 0;
    271 	for (more = 1; more;) {
    272 		switch (*p) {
    273 		case '\0':
    274 			p++;	/* Skip nul */
    275 			goto check;
    276 
    277 		case '\t':
    278 		case ' ':
    279 			break;
    280 
    281 		case '\n':
    282 			parsenleft = q - parsenextc;
    283 			more = 0; /* Stop processing here */
    284 			break;
    285 
    286 		default:
    287 			something = 1;
    288 			break;
    289 		}
    290 
    291 		*q++ = *p++;
    292 check:
    293 		if (--parselleft <= 0) {
    294 			parsenleft = q - parsenextc - 1;
    295 			if (parsenleft < 0)
    296 				goto again;
    297 			*q = '\0';
    298 			more = 0;
    299 		}
    300 	}
    301 
    302 	savec = *q;
    303 	*q = '\0';
    304 
    305 #ifndef SMALL
    306 	if (parsefile->fd == 0 && hist && something) {
    307 		HistEvent he;
    308 		INTOFF;
    309 		history(hist, &he, whichprompt == 1? H_ENTER : H_APPEND,
    310 		    parsenextc);
    311 		INTON;
    312 	}
    313 #endif
    314 
    315 	if (vflag) {
    316 		out2str(parsenextc);
    317 		flushout(out2);
    318 	}
    319 
    320 	*q = savec;
    321 
    322 	return *parsenextc++;
    323 }
    324 
    325 /*
    326  * Undo the last call to pgetc.  Only one character may be pushed back.
    327  * PEOF may be pushed back.
    328  */
    329 
    330 void
    331 pungetc(void)
    332 {
    333 	parsenleft++;
    334 	parsenextc--;
    335 }
    336 
    337 /*
    338  * Push a string back onto the input at this current parsefile level.
    339  * We handle aliases this way.
    340  */
    341 void
    342 pushstring(char *s, int len, void *ap)
    343 {
    344 	struct strpush *sp;
    345 
    346 	INTOFF;
    347 /*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
    348 	if (parsefile->strpush) {
    349 		sp = ckmalloc(sizeof (struct strpush));
    350 		sp->prev = parsefile->strpush;
    351 		parsefile->strpush = sp;
    352 	} else
    353 		sp = parsefile->strpush = &(parsefile->basestrpush);
    354 	sp->prevstring = parsenextc;
    355 	sp->prevnleft = parsenleft;
    356 	sp->prevlleft = parselleft;
    357 	sp->ap = (struct alias *)ap;
    358 	if (ap)
    359 		((struct alias *)ap)->flag |= ALIASINUSE;
    360 	parsenextc = s;
    361 	parsenleft = len;
    362 	INTON;
    363 }
    364 
    365 void
    366 popstring(void)
    367 {
    368 	struct strpush *sp = parsefile->strpush;
    369 
    370 	INTOFF;
    371 	parsenextc = sp->prevstring;
    372 	parsenleft = sp->prevnleft;
    373 	parselleft = sp->prevlleft;
    374 /*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
    375 	if (sp->ap)
    376 		sp->ap->flag &= ~ALIASINUSE;
    377 	parsefile->strpush = sp->prev;
    378 	if (sp != &(parsefile->basestrpush))
    379 		ckfree(sp);
    380 	INTON;
    381 }
    382 
    383 /*
    384  * Set the input to take input from a file.  If push is set, push the
    385  * old input onto the stack first.
    386  */
    387 
    388 void
    389 setinputfile(const char *fname, int push)
    390 {
    391 	int fd;
    392 	int fd2;
    393 
    394 	INTOFF;
    395 	if ((fd = open(fname, O_RDONLY)) < 0)
    396 		error("Can't open %s", fname);
    397 	if (fd < 10) {
    398 		fd2 = copyfd(fd, 10);
    399 		close(fd);
    400 		if (fd2 < 0)
    401 			error("Out of file descriptors");
    402 		fd = fd2;
    403 	}
    404 	setinputfd(fd, push);
    405 	INTON;
    406 }
    407 
    408 
    409 /*
    410  * Like setinputfile, but takes an open file descriptor.  Call this with
    411  * interrupts off.
    412  */
    413 
    414 void
    415 setinputfd(int fd, int push)
    416 {
    417 	(void) fcntl(fd, F_SETFD, FD_CLOEXEC);
    418 	if (push) {
    419 		pushfile();
    420 		parsefile->buf = ckmalloc(BUFSIZ);
    421 	}
    422 	if (parsefile->fd > 0)
    423 		close(parsefile->fd);
    424 	parsefile->fd = fd;
    425 	if (parsefile->buf == NULL)
    426 		parsefile->buf = ckmalloc(BUFSIZ);
    427 	parselleft = parsenleft = 0;
    428 	plinno = 1;
    429 }
    430 
    431 
    432 /*
    433  * Like setinputfile, but takes input from a string.
    434  */
    435 
    436 void
    437 setinputstring(char *string, int push)
    438 {
    439 	INTOFF;
    440 	if (push)
    441 		pushfile();
    442 	parsenextc = string;
    443 	parselleft = parsenleft = strlen(string);
    444 	parsefile->buf = NULL;
    445 	plinno = 1;
    446 	INTON;
    447 }
    448 
    449 
    450 
    451 /*
    452  * To handle the "." command, a stack of input files is used.  Pushfile
    453  * adds a new entry to the stack and popfile restores the previous level.
    454  */
    455 
    456 STATIC void
    457 pushfile(void)
    458 {
    459 	struct parsefile *pf;
    460 
    461 	parsefile->nleft = parsenleft;
    462 	parsefile->lleft = parselleft;
    463 	parsefile->nextc = parsenextc;
    464 	parsefile->linno = plinno;
    465 	pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
    466 	pf->prev = parsefile;
    467 	pf->fd = -1;
    468 	pf->strpush = NULL;
    469 	pf->basestrpush.prev = NULL;
    470 	parsefile = pf;
    471 }
    472 
    473 
    474 void
    475 popfile(void)
    476 {
    477 	struct parsefile *pf = parsefile;
    478 
    479 	INTOFF;
    480 	if (pf->fd >= 0)
    481 		close(pf->fd);
    482 	if (pf->buf)
    483 		ckfree(pf->buf);
    484 	while (pf->strpush)
    485 		popstring();
    486 	parsefile = pf->prev;
    487 	ckfree(pf);
    488 	parsenleft = parsefile->nleft;
    489 	parselleft = parsefile->lleft;
    490 	parsenextc = parsefile->nextc;
    491 	plinno = parsefile->linno;
    492 	INTON;
    493 }
    494 
    495 
    496 /*
    497  * Return to top level.
    498  */
    499 
    500 void
    501 popallfiles(void)
    502 {
    503 	while (parsefile != &basepf)
    504 		popfile();
    505 }
    506 
    507 
    508 
    509 /*
    510  * Close the file(s) that the shell is reading commands from.  Called
    511  * after a fork is done.
    512  *
    513  * Takes one arg, vfork, which tells it to not modify its global vars
    514  * as it is still running in the parent.
    515  *
    516  * This code is (probably) unnecessary as the 'close on exec' flag is
    517  * set and should be enough.  In the vfork case it is definitely wrong
    518  * to close the fds as another fork() may be done later to feed data
    519  * from a 'here' document into a pipe and we don't want to close the
    520  * pipe!
    521  */
    522 
    523 void
    524 closescript(int vforked)
    525 {
    526 	if (vforked)
    527 		return;
    528 	popallfiles();
    529 	if (parsefile->fd > 0) {
    530 		close(parsefile->fd);
    531 		parsefile->fd = 0;
    532 	}
    533 }
    534