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      1 /*	$NetBSD: input.c,v 1.39 2003/08/07 09:05:32 agc 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
     38 static char sccsid[] = "@(#)input.c	8.3 (Berkeley) 6/9/95";
     39 #else
     40 __RCSID("$NetBSD: input.c,v 1.39 2003/08/07 09:05:32 agc 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 
     69 MKINIT
     70 struct 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 
     83 MKINIT
     84 struct 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 
     97 int plinno = 1;			/* input line number */
     98 int parsenleft;			/* copy of parsefile->nleft */
     99 MKINIT int parselleft;		/* copy of parsefile->lleft */
    100 char *parsenextc;		/* copy of parsefile->nextc */
    101 MKINIT struct parsefile basepf;	/* top level input file */
    102 MKINIT char basebuf[BUFSIZ];	/* buffer for top level input file */
    103 struct parsefile *parsefile = &basepf;	/* current input file */
    104 int init_editline = 0;		/* editline library initialized? */
    105 int whichprompt;		/* 1 == PS1, 2 == PS2 */
    106 
    107 #if WITH_HISTORY
    108 EditLine *el;			/* cookie for editline package */
    109 #endif
    110 
    111 STATIC void pushfile(void);
    112 static int preadfd(void);
    113 
    114 #ifdef mkinit
    115 INCLUDE <stdio.h>
    116 INCLUDE "input.h"
    117 INCLUDE "error.h"
    118 
    119 INIT {
    120 	basepf.nextc = basepf.buf = basebuf;
    121 }
    122 
    123 RESET {
    124 	if (exception != EXSHELLPROC)
    125 		parselleft = parsenleft = 0;	/* clear input buffer */
    126 	popallfiles();
    127 }
    128 
    129 SHELLPROC {
    130 	popallfiles();
    131 }
    132 #endif
    133 
    134 
    135 /*
    136  * Read a line from the script.
    137  */
    138 
    139 char *
    140 pfgets(char *line, int len)
    141 {
    142 	char *p = line;
    143 	int nleft = len;
    144 	int c;
    145 
    146 	while (--nleft > 0) {
    147 		c = pgetc_macro();
    148 		if (c == PEOF) {
    149 			if (p == line)
    150 				return NULL;
    151 			break;
    152 		}
    153 		*p++ = c;
    154 		if (c == '\n')
    155 			break;
    156 	}
    157 	*p = '\0';
    158 	return line;
    159 }
    160 
    161 
    162 
    163 /*
    164  * Read a character from the script, returning PEOF on end of file.
    165  * Nul characters in the input are silently discarded.
    166  */
    167 
    168 int
    169 pgetc(void)
    170 {
    171 	return pgetc_macro();
    172 }
    173 
    174 
    175 static int
    176 preadfd(void)
    177 {
    178 	int nr;
    179 	char *buf =  parsefile->buf;
    180 	parsenextc = buf;
    181 
    182 retry:
    183 #ifdef WITH_HISTORY
    184 	if (parsefile->fd == 0 && el) {
    185 		static const char *rl_cp;
    186 		static int el_len;
    187 
    188 		if (rl_cp == NULL)
    189 			rl_cp = el_gets(el, &el_len);
    190 		if (rl_cp == NULL)
    191 			nr = 0;
    192 		else {
    193 			nr = el_len;
    194 			if (nr > BUFSIZ - 8)
    195 				nr = BUFSIZ - 8;
    196 			memcpy(buf, rl_cp, nr);
    197 			if (nr != el_len) {
    198 				el_len -= nr;
    199 				rl_cp += nr;
    200 			} else
    201 				rl_cp = 0;
    202 		}
    203 
    204 	} else
    205 #endif
    206 		nr = read(parsefile->fd, buf, BUFSIZ - 8);
    207 
    208 
    209 	if (nr <= 0) {
    210                 if (nr < 0) {
    211                         if (errno == EINTR)
    212                                 goto retry;
    213                         if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
    214                                 int flags = fcntl(0, F_GETFL, 0);
    215                                 if (flags >= 0 && flags & O_NONBLOCK) {
    216                                         flags &=~ O_NONBLOCK;
    217                                         if (fcntl(0, F_SETFL, flags) >= 0) {
    218 						out2str("sh: turning off NDELAY mode\n");
    219                                                 goto retry;
    220                                         }
    221                                 }
    222                         }
    223                 }
    224                 nr = -1;
    225 	}
    226 	return nr;
    227 }
    228 
    229 /*
    230  * Refill the input buffer and return the next input character:
    231  *
    232  * 1) If a string was pushed back on the input, pop it;
    233  * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
    234  *    from a string so we can't refill the buffer, return EOF.
    235  * 3) If the is more stuff in this buffer, use it else call read to fill it.
    236  * 4) Process input up to the next newline, deleting nul characters.
    237  */
    238 
    239 int
    240 preadbuffer(void)
    241 {
    242 	char *p, *q;
    243 	int more;
    244 	int something;
    245 	char savec;
    246 
    247 	if (parsefile->strpush) {
    248 		popstring();
    249 		if (--parsenleft >= 0)
    250 			return (*parsenextc++);
    251 	}
    252 	if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
    253 		return PEOF;
    254 	flushout(&output);
    255 	flushout(&errout);
    256 
    257 again:
    258 	if (parselleft <= 0) {
    259 		if ((parselleft = preadfd()) == -1) {
    260 			parselleft = parsenleft = EOF_NLEFT;
    261 			return PEOF;
    262 		}
    263 	}
    264 
    265 	q = p = parsenextc;
    266 
    267 	/* delete nul characters */
    268 	something = 0;
    269 	for (more = 1; more;) {
    270 		switch (*p) {
    271 		case '\0':
    272 			p++;	/* Skip nul */
    273 			goto check;
    274 
    275 		case '\t':
    276 		case ' ':
    277 			break;
    278 
    279 		case '\n':
    280 			parsenleft = q - parsenextc;
    281 			more = 0; /* Stop processing here */
    282 			break;
    283 
    284 		default:
    285 			something = 1;
    286 			break;
    287 		}
    288 
    289 		*q++ = *p++;
    290 check:
    291 		if (--parselleft <= 0) {
    292 			parsenleft = q - parsenextc - 1;
    293 			if (parsenleft < 0)
    294 				goto again;
    295 			*q = '\0';
    296 			more = 0;
    297 		}
    298 	}
    299 
    300 	savec = *q;
    301 	*q = '\0';
    302 
    303 #ifdef WITH_HISTORY
    304 	if (parsefile->fd == 0 && hist && something) {
    305 		HistEvent he;
    306 		INTOFF;
    307 		history(hist, &he, whichprompt == 1? H_ENTER : H_APPEND,
    308 		    parsenextc);
    309 		INTON;
    310 	}
    311 #endif
    312 
    313 	if (vflag) {
    314 		out2str(parsenextc);
    315 		flushout(out2);
    316 	}
    317 
    318 	*q = savec;
    319 
    320 	return *parsenextc++;
    321 }
    322 
    323 /*
    324  * Undo the last call to pgetc.  Only one character may be pushed back.
    325  * PEOF may be pushed back.
    326  */
    327 
    328 void
    329 pungetc(void)
    330 {
    331 	parsenleft++;
    332 	parsenextc--;
    333 }
    334 
    335 /*
    336  * Push a string back onto the input at this current parsefile level.
    337  * We handle aliases this way.
    338  */
    339 void
    340 pushstring(char *s, int len, void *ap)
    341 {
    342 	struct strpush *sp;
    343 
    344 	INTOFF;
    345 /*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
    346 	if (parsefile->strpush) {
    347 		sp = ckmalloc(sizeof (struct strpush));
    348 		sp->prev = parsefile->strpush;
    349 		parsefile->strpush = sp;
    350 	} else
    351 		sp = parsefile->strpush = &(parsefile->basestrpush);
    352 	sp->prevstring = parsenextc;
    353 	sp->prevnleft = parsenleft;
    354 	sp->prevlleft = parselleft;
    355 	sp->ap = (struct alias *)ap;
    356 	if (ap)
    357 		((struct alias *)ap)->flag |= ALIASINUSE;
    358 	parsenextc = s;
    359 	parsenleft = len;
    360 	INTON;
    361 }
    362 
    363 void
    364 popstring(void)
    365 {
    366 	struct strpush *sp = parsefile->strpush;
    367 
    368 	INTOFF;
    369 	parsenextc = sp->prevstring;
    370 	parsenleft = sp->prevnleft;
    371 	parselleft = sp->prevlleft;
    372 /*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
    373 	if (sp->ap)
    374 		sp->ap->flag &= ~ALIASINUSE;
    375 	parsefile->strpush = sp->prev;
    376 	if (sp != &(parsefile->basestrpush))
    377 		ckfree(sp);
    378 	INTON;
    379 }
    380 
    381 /*
    382  * Set the input to take input from a file.  If push is set, push the
    383  * old input onto the stack first.
    384  */
    385 
    386 void
    387 setinputfile(const char *fname, int push)
    388 {
    389 	int fd;
    390 	int fd2;
    391 
    392 	INTOFF;
    393 	if ((fd = open(fname, O_RDONLY)) < 0)
    394 		error("Can't open %s", fname);
    395 	if (fd < 10) {
    396 		fd2 = copyfd(fd, 10);
    397 		close(fd);
    398 		if (fd2 < 0)
    399 			error("Out of file descriptors");
    400 		fd = fd2;
    401 	}
    402 	setinputfd(fd, push);
    403 	INTON;
    404 }
    405 
    406 
    407 /*
    408  * Like setinputfile, but takes an open file descriptor.  Call this with
    409  * interrupts off.
    410  */
    411 
    412 void
    413 setinputfd(int fd, int push)
    414 {
    415 	(void) fcntl(fd, F_SETFD, FD_CLOEXEC);
    416 	if (push) {
    417 		pushfile();
    418 		parsefile->buf = ckmalloc(BUFSIZ);
    419 	}
    420 	if (parsefile->fd > 0)
    421 		close(parsefile->fd);
    422 	parsefile->fd = fd;
    423 	if (parsefile->buf == NULL)
    424 		parsefile->buf = ckmalloc(BUFSIZ);
    425 	parselleft = parsenleft = 0;
    426 	plinno = 1;
    427 }
    428 
    429 
    430 /*
    431  * Like setinputfile, but takes input from a string.
    432  */
    433 
    434 void
    435 setinputstring(char *string, int push)
    436 {
    437 	INTOFF;
    438 	if (push)
    439 		pushfile();
    440 	parsenextc = string;
    441 	parselleft = parsenleft = strlen(string);
    442 	parsefile->buf = NULL;
    443 	plinno = 1;
    444 	INTON;
    445 }
    446 
    447 
    448 
    449 /*
    450  * To handle the "." command, a stack of input files is used.  Pushfile
    451  * adds a new entry to the stack and popfile restores the previous level.
    452  */
    453 
    454 STATIC void
    455 pushfile(void)
    456 {
    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(void)
    474 {
    475 	struct parsefile *pf = parsefile;
    476 
    477 	INTOFF;
    478 	if (pf->fd >= 0)
    479 		close(pf->fd);
    480 	if (pf->buf)
    481 		ckfree(pf->buf);
    482 	while (pf->strpush)
    483 		popstring();
    484 	parsefile = pf->prev;
    485 	ckfree(pf);
    486 	parsenleft = parsefile->nleft;
    487 	parselleft = parsefile->lleft;
    488 	parsenextc = parsefile->nextc;
    489 	plinno = parsefile->linno;
    490 	INTON;
    491 }
    492 
    493 
    494 /*
    495  * Return to top level.
    496  */
    497 
    498 void
    499 popallfiles(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  * Takes one arg, vfork, which tells it to not modify its global vars
    512  * as it is still running in the parent.
    513  *
    514  * This code is (probably) unnecessary as the 'close on exec' flag is
    515  * set and should be enough.  In the vfork case it is definitely wrong
    516  * to close the fds as another fork() may be done later to feed data
    517  * from a 'here' document into a pipe and we don't want to close the
    518  * pipe!
    519  */
    520 
    521 void
    522 closescript(int vforked)
    523 {
    524 	if (vforked)
    525 		return;
    526 	popallfiles();
    527 	if (parsefile->fd > 0) {
    528 		close(parsefile->fd);
    529 		parsefile->fd = 0;
    530 	}
    531 }
    532