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 38 static 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 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 EditLine *el; /* cookie for editline package */ 108 109 STATIC void pushfile(void); 110 static int preadfd(void); 111 112 #ifdef mkinit 113 INCLUDE <stdio.h> 114 INCLUDE "input.h" 115 INCLUDE "error.h" 116 117 INIT { 118 basepf.nextc = basepf.buf = basebuf; 119 } 120 121 RESET { 122 if (exception != EXSHELLPROC) 123 parselleft = parsenleft = 0; /* clear input buffer */ 124 popallfiles(); 125 } 126 127 SHELLPROC { 128 popallfiles(); 129 } 130 #endif 131 132 133 /* 134 * Read a line from the script. 135 */ 136 137 char * 138 pfgets(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 */ 165 166 int 167 pgetc(void) 168 { 169 return pgetc_macro(); 170 } 171 172 173 static int 174 preadfd(void) 175 { 176 int nr; 177 char *buf = parsefile->buf; 178 parsenextc = buf; 179 180 retry: 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 */ 236 237 int 238 preadbuffer(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); 254 255 again: 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++; 288 check: 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 */ 325 326 void 327 pungetc(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 */ 337 void 338 pushstring(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 } 360 361 void 362 popstring(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 */ 383 384 void 385 setinputfile(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 */ 425 426 void 427 setinputfd(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 */ 447 448 void 449 setinputstring(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 */ 467 468 STATIC void 469 pushfile(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 } 484 485 486 void 487 popfile(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 */ 511 512 void 513 popallfiles(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 */ 534 535 void 536 closescript(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