1 /* $NetBSD: input.c,v 1.71 2019/02/09 09:20:47 kre 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 1.71 2019/02/09 09:20:47 kre 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 <limits.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <sys/stat.h> 52 53 /* 54 * This file implements the input routines used by the parser. 55 */ 56 57 #include "shell.h" 58 #include "redir.h" 59 #include "syntax.h" 60 #include "input.h" 61 #include "output.h" 62 #include "options.h" 63 #include "memalloc.h" 64 #include "error.h" 65 #include "alias.h" 66 #include "parser.h" 67 #include "myhistedit.h" 68 #include "show.h" 69 70 #define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */ 71 72 MKINIT 73 struct strpush { 74 struct strpush *prev; /* preceding string on stack */ 75 const char *prevstring; 76 int prevnleft; 77 int prevlleft; 78 struct alias *ap; /* if push was associated with an alias */ 79 }; 80 81 /* 82 * The parsefile structure pointed to by the global variable parsefile 83 * contains information about the current file being read. 84 */ 85 86 MKINIT 87 struct parsefile { 88 struct parsefile *prev; /* preceding file on stack */ 89 int linno; /* current line */ 90 int fd; /* file descriptor (or -1 if string) */ 91 int nleft; /* number of chars left in this line */ 92 int lleft; /* number of chars left in this buffer */ 93 const char *nextc; /* next char in buffer */ 94 char *buf; /* input buffer */ 95 struct strpush *strpush; /* for pushing strings at this level */ 96 struct strpush basestrpush; /* so pushing one is fast */ 97 }; 98 99 100 int plinno = 1; /* input line number */ 101 int parsenleft; /* copy of parsefile->nleft */ 102 MKINIT int parselleft; /* copy of parsefile->lleft */ 103 const char *parsenextc; /* copy of parsefile->nextc */ 104 MKINIT struct parsefile basepf; /* top level input file */ 105 MKINIT char basebuf[BUFSIZ]; /* buffer for top level input file */ 106 struct parsefile *parsefile = &basepf; /* current input file */ 107 int init_editline = 0; /* editline library initialized? */ 108 int whichprompt; /* 1 == PS1, 2 == PS2 */ 109 110 STATIC void pushfile(void); 111 static int preadfd(void); 112 113 #ifdef mkinit 114 INCLUDE <stdio.h> 115 INCLUDE "input.h" 116 INCLUDE "error.h" 117 118 INIT { 119 basepf.nextc = basepf.buf = basebuf; 120 } 121 122 RESET { 123 if (exception != EXSHELLPROC) 124 parselleft = parsenleft = 0; /* clear input buffer */ 125 popallfiles(); 126 } 127 128 SHELLPROC { 129 popallfiles(); 130 } 131 #endif 132 133 134 #if 0 /* this is unused */ 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 == PFAKE) /* consecutive PFAKEs is impossible */ 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 plinno++; 158 break; 159 } 160 } 161 *p = '\0'; 162 return line; 163 } 164 #endif 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(void) 174 { 175 int c; 176 177 c = pgetc_macro(); 178 if (c == PFAKE) 179 c = pgetc_macro(); 180 return c; 181 } 182 183 184 static int 185 preadfd(void) 186 { 187 int nr; 188 char *buf = parsefile->buf; 189 parsenextc = buf; 190 191 retry: 192 #ifndef SMALL 193 if (parsefile->fd == 0 && el) { 194 static const char *rl_cp; 195 static int el_len; 196 197 if (rl_cp == NULL) 198 rl_cp = el_gets(el, &el_len); 199 if (rl_cp == NULL) 200 nr = el_len == 0 ? 0 : -1; 201 else { 202 nr = el_len; 203 if (nr > BUFSIZ - 8) 204 nr = BUFSIZ - 8; 205 memcpy(buf, rl_cp, nr); 206 if (nr != el_len) { 207 el_len -= nr; 208 rl_cp += nr; 209 } else 210 rl_cp = 0; 211 } 212 213 } else 214 #endif 215 nr = read(parsefile->fd, buf, BUFSIZ - 8); 216 217 218 if (nr <= 0) { 219 if (nr < 0) { 220 if (errno == EINTR) 221 goto retry; 222 if (parsefile->fd == 0 && errno == EWOULDBLOCK) { 223 int flags = fcntl(0, F_GETFL, 0); 224 225 if (flags >= 0 && flags & O_NONBLOCK) { 226 flags &=~ O_NONBLOCK; 227 if (fcntl(0, F_SETFL, flags) >= 0) { 228 out2str("sh: turning off NDELAY mode\n"); 229 goto retry; 230 } 231 } 232 } 233 } 234 nr = -1; 235 } 236 return nr; 237 } 238 239 /* 240 * Refill the input buffer and return the next input character: 241 * 242 * 1) If a string was pushed back on the input, pop it; 243 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading 244 * from a string so we can't refill the buffer, return EOF. 245 * 3) If there is more stuff in this buffer, use it else call read to fill it. 246 * 4) Process input up to the next newline, deleting nul characters. 247 */ 248 249 int 250 preadbuffer(void) 251 { 252 char *p, *q; 253 int more; 254 #ifndef SMALL 255 int something; 256 #endif 257 char savec; 258 259 while (parsefile->strpush) { 260 if (parsenleft == -1 && parsefile->strpush->ap != NULL) 261 return PFAKE; 262 popstring(); 263 if (--parsenleft >= 0) 264 return (*parsenextc++); 265 } 266 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 267 return PEOF; 268 flushout(&output); 269 flushout(&errout); 270 271 again: 272 if (parselleft <= 0) { 273 if ((parselleft = preadfd()) == -1) { 274 parselleft = parsenleft = EOF_NLEFT; 275 return PEOF; 276 } 277 } 278 279 /* p = (not const char *)parsenextc; */ 280 p = parsefile->buf + (parsenextc - parsefile->buf); 281 q = p; 282 283 /* delete nul characters */ 284 #ifndef SMALL 285 something = 0; 286 #endif 287 for (more = 1; more;) { 288 switch (*p) { 289 case '\0': 290 p++; /* Skip nul */ 291 goto check; 292 293 case '\t': 294 case ' ': 295 break; 296 297 case '\n': 298 parsenleft = q - parsenextc; 299 more = 0; /* Stop processing here */ 300 break; 301 302 default: 303 #ifndef SMALL 304 something = 1; 305 #endif 306 break; 307 } 308 309 *q++ = *p++; 310 check: 311 if (--parselleft <= 0) { 312 parsenleft = q - parsenextc - 1; 313 if (parsenleft < 0) 314 goto again; 315 *q = '\0'; 316 more = 0; 317 } 318 } 319 320 savec = *q; 321 *q = '\0'; 322 323 #ifndef SMALL 324 if (parsefile->fd == 0 && hist && (something || whichprompt == 2)) { 325 HistEvent he; 326 327 INTOFF; 328 history(hist, &he, whichprompt != 2 ? H_ENTER : H_APPEND, 329 parsenextc); 330 INTON; 331 } 332 #endif 333 334 if (vflag) { 335 out2str(parsenextc); 336 flushout(out2); 337 } 338 339 *q = savec; 340 341 return *parsenextc++; 342 } 343 344 /* 345 * Test whether we have reached EOF on input stream. 346 * Return true only if certain (without attempting a read). 347 * 348 * Note the similarity to the opening section of preadbuffer() 349 */ 350 int 351 at_eof(void) 352 { 353 struct strpush *sp = parsefile->strpush; 354 355 if (parsenleft > 0) /* more chars are in the buffer */ 356 return 0; 357 358 while (sp != NULL) { 359 /* 360 * If any pushed string has any remaining data, 361 * then we are not at EOF (simulating popstring()) 362 */ 363 if (sp->prevnleft > 0) 364 return 0; 365 sp = sp->prev; 366 } 367 368 /* 369 * If we reached real EOF and pushed it back, 370 * or if we are just processing a string (not reading a file) 371 * then there is no more. Note that if a file pushes a 372 * string, the file's ->buf remains present. 373 */ 374 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 375 return 1; 376 377 /* 378 * In other cases, there might be more 379 */ 380 return 0; 381 } 382 383 /* 384 * Undo the last call to pgetc. Only one character may be pushed back. 385 * PEOF may be pushed back. 386 */ 387 388 void 389 pungetc(void) 390 { 391 parsenleft++; 392 parsenextc--; 393 } 394 395 /* 396 * Push a string back onto the input at this current parsefile level. 397 * We handle aliases this way. 398 */ 399 void 400 pushstring(const char *s, int len, struct alias *ap) 401 { 402 struct strpush *sp; 403 404 VTRACE(DBG_INPUT, 405 ("pushstring(\"%.*s\", %d)%s%s%s had: nl=%d ll=%d \"%.*s\"\n", 406 len, s, len, ap ? " for alias:'" : "", 407 ap ? ap->name : "", ap ? "'" : "", 408 parsenleft, parselleft, parsenleft, parsenextc)); 409 410 INTOFF; 411 if (parsefile->strpush) { 412 sp = ckmalloc(sizeof (struct strpush)); 413 sp->prev = parsefile->strpush; 414 parsefile->strpush = sp; 415 } else 416 sp = parsefile->strpush = &(parsefile->basestrpush); 417 418 sp->prevstring = parsenextc; 419 sp->prevnleft = parsenleft; 420 sp->prevlleft = parselleft; 421 sp->ap = ap; 422 if (ap) 423 ap->flag |= ALIASINUSE; 424 parsenextc = s; 425 parsenleft = len; 426 INTON; 427 } 428 429 void 430 popstring(void) 431 { 432 struct strpush *sp = parsefile->strpush; 433 434 INTOFF; 435 if (sp->ap) { 436 int alen; 437 438 if ((alen = strlen(sp->ap->val)) > 0 && 439 (sp->ap->val[alen - 1] == ' ' || 440 sp->ap->val[alen - 1] == '\t')) 441 checkkwd |= CHKALIAS; 442 sp->ap->flag &= ~ALIASINUSE; 443 } 444 parsenextc = sp->prevstring; 445 parsenleft = sp->prevnleft; 446 parselleft = sp->prevlleft; 447 448 VTRACE(DBG_INPUT, ("popstring()%s%s%s nl=%d ll=%d \"%.*s\"\n", 449 sp->ap ? " from alias:'" : "", sp->ap ? sp->ap->name : "", 450 sp->ap ? "'" : "", parsenleft, parselleft, parsenleft, parsenextc)); 451 452 parsefile->strpush = sp->prev; 453 if (sp != &(parsefile->basestrpush)) 454 ckfree(sp); 455 INTON; 456 } 457 458 /* 459 * Set the input to take input from a file. If push is set, push the 460 * old input onto the stack first. 461 */ 462 463 void 464 setinputfile(const char *fname, int push) 465 { 466 unsigned char magic[4]; 467 int fd; 468 int fd2; 469 struct stat sb; 470 471 CTRACE(DBG_INPUT,("setinputfile(\"%s\", %spush)\n",fname,push?"":"no")); 472 473 INTOFF; 474 if ((fd = open(fname, O_RDONLY)) < 0) 475 error("Can't open %s", fname); 476 477 /* Since the message "Syntax error: "(" unexpected" is not very 478 * helpful, we check if the file starts with the ELF magic to 479 * avoid that message. The first lseek tries to make sure that 480 * we can later rewind the file. 481 */ 482 if (fstat(fd, &sb) == 0 && S_ISREG(sb.st_mode) && 483 lseek(fd, 0, SEEK_SET) == 0) { 484 if (read(fd, magic, 4) == 4) { 485 if (memcmp(magic, "\177ELF", 4) == 0) { 486 (void)close(fd); 487 error("Cannot execute ELF binary %s", fname); 488 } 489 } 490 if (lseek(fd, 0, SEEK_SET) != 0) { 491 (void)close(fd); 492 error("Cannot rewind the file %s", fname); 493 } 494 } 495 496 fd2 = to_upper_fd(fd); /* closes fd, returns higher equiv */ 497 if (fd2 == fd) { 498 (void) close(fd); 499 error("Out of file descriptors"); 500 } 501 502 setinputfd(fd2, push); 503 INTON; 504 } 505 506 /* 507 * When a shell fd needs to be altered (when the user wants to use 508 * the same fd - rare, but happens - we need to locate the ref to 509 * the fd, and update it. This happens via a callback. 510 * This is the callback func for fd's used for shell input 511 */ 512 static void 513 input_fd_swap(int from, int to) 514 { 515 struct parsefile *pf; 516 517 pf = parsefile; 518 while (pf != NULL) { /* don't need to stop at basepf */ 519 if (pf->fd == from) 520 pf->fd = to; 521 pf = pf->prev; 522 } 523 } 524 525 /* 526 * Like setinputfile, but takes an open file descriptor. Call this with 527 * interrupts off. 528 */ 529 530 void 531 setinputfd(int fd, int push) 532 { 533 VTRACE(DBG_INPUT, ("setinputfd(%d, %spush)\n", fd, push?"":"no")); 534 535 INTOFF; 536 register_sh_fd(fd, input_fd_swap); 537 (void) fcntl(fd, F_SETFD, FD_CLOEXEC); 538 if (push) 539 pushfile(); 540 if (parsefile->fd > 0) 541 sh_close(parsefile->fd); 542 parsefile->fd = fd; 543 if (parsefile->buf == NULL) 544 parsefile->buf = ckmalloc(BUFSIZ); 545 parselleft = parsenleft = 0; 546 plinno = 1; 547 INTON; 548 549 CTRACE(DBG_INPUT, ("setinputfd(%d, %spush) done; plinno=1\n", fd, 550 push ? "" : "no")); 551 } 552 553 554 /* 555 * Like setinputfile, but takes input from a string. 556 */ 557 558 void 559 setinputstring(char *string, int push, int line1) 560 { 561 562 INTOFF; 563 if (push) /* XXX: always, as it happens */ 564 pushfile(); 565 parsenextc = string; 566 parselleft = parsenleft = strlen(string); 567 plinno = line1; 568 INTON; 569 570 CTRACE(DBG_INPUT, 571 ("setinputstring(\"%.20s%s\" (%d), %spush, @ %d)\n", string, 572 (parsenleft > 20 ? "..." : ""), parsenleft, push?"":"no", line1)); 573 } 574 575 576 577 /* 578 * To handle the "." command, a stack of input files is used. Pushfile 579 * adds a new entry to the stack and popfile restores the previous level. 580 */ 581 582 STATIC void 583 pushfile(void) 584 { 585 struct parsefile *pf; 586 587 VTRACE(DBG_INPUT, 588 ("pushfile(): fd=%d buf=%p nl=%d ll=%d \"%.*s\" plinno=%d\n", 589 parsefile->fd, parsefile->buf, parsenleft, parselleft, 590 parsenleft, parsenextc, plinno)); 591 592 parsefile->nleft = parsenleft; 593 parsefile->lleft = parselleft; 594 parsefile->nextc = parsenextc; 595 parsefile->linno = plinno; 596 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile)); 597 pf->prev = parsefile; 598 pf->fd = -1; 599 pf->strpush = NULL; 600 pf->basestrpush.prev = NULL; 601 pf->buf = NULL; 602 parsefile = pf; 603 } 604 605 606 void 607 popfile(void) 608 { 609 struct parsefile *pf = parsefile; 610 611 INTOFF; 612 if (pf->fd >= 0) 613 sh_close(pf->fd); 614 if (pf->buf) 615 ckfree(pf->buf); 616 while (pf->strpush) 617 popstring(); 618 parsefile = pf->prev; 619 ckfree(pf); 620 parsenleft = parsefile->nleft; 621 parselleft = parsefile->lleft; 622 parsenextc = parsefile->nextc; 623 624 VTRACE(DBG_INPUT, 625 ("popfile(): fd=%d buf=%p nl=%d ll=%d \"%.*s\" plinno:%d->%d\n", 626 parsefile->fd, parsefile->buf, parsenleft, parselleft, 627 parsenleft, parsenextc, plinno, parsefile->linno)); 628 629 plinno = parsefile->linno; 630 INTON; 631 } 632 633 /* 634 * Return current file (to go back to it later using popfilesupto()). 635 */ 636 637 struct parsefile * 638 getcurrentfile(void) 639 { 640 return parsefile; 641 } 642 643 644 /* 645 * Pop files until the given file is on top again. Useful for regular 646 * builtins that read shell commands from files or strings. 647 * If the given file is not an active file, an error is raised. 648 */ 649 650 void 651 popfilesupto(struct parsefile *file) 652 { 653 while (parsefile != file && parsefile != &basepf) 654 popfile(); 655 if (parsefile != file) 656 error("popfilesupto() misused"); 657 } 658 659 660 /* 661 * Return to top level. 662 */ 663 664 void 665 popallfiles(void) 666 { 667 while (parsefile != &basepf) 668 popfile(); 669 } 670 671 672 673 /* 674 * Close the file(s) that the shell is reading commands from. Called 675 * after a fork is done. 676 * 677 * Takes one arg, vfork, which tells it to not modify its global vars 678 * as it is still running in the parent. 679 * 680 * This code is (probably) unnecessary as the 'close on exec' flag is 681 * set and should be enough. In the vfork case it is definitely wrong 682 * to close the fds as another fork() may be done later to feed data 683 * from a 'here' document into a pipe and we don't want to close the 684 * pipe! 685 */ 686 687 void 688 closescript(int vforked) 689 { 690 if (vforked) 691 return; 692 popallfiles(); 693 if (parsefile->fd > 0) { 694 sh_close(parsefile->fd); 695 parsefile->fd = 0; 696 } 697 } 698