1 /* $NetBSD: input.c,v 1.62 2017/08/19 21:13:11 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 1.62 2017/08/19 21:13:11 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 == 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 #endif 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 #ifndef SMALL 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 = el_len == 0 ? 0 : -1; 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); 215 216 if (flags >= 0 && flags & O_NONBLOCK) { 217 flags &=~ O_NONBLOCK; 218 if (fcntl(0, F_SETFL, flags) >= 0) { 219 out2str("sh: turning off NDELAY mode\n"); 220 goto retry; 221 } 222 } 223 } 224 } 225 nr = -1; 226 } 227 return nr; 228 } 229 230 /* 231 * Refill the input buffer and return the next input character: 232 * 233 * 1) If a string was pushed back on the input, pop it; 234 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading 235 * from a string so we can't refill the buffer, return EOF. 236 * 3) If the is more stuff in this buffer, use it else call read to fill it. 237 * 4) Process input up to the next newline, deleting nul characters. 238 */ 239 240 int 241 preadbuffer(void) 242 { 243 char *p, *q; 244 int more; 245 #ifndef SMALL 246 int something; 247 #endif 248 char savec; 249 250 while (parsefile->strpush) { 251 popstring(); 252 if (--parsenleft >= 0) 253 return (*parsenextc++); 254 } 255 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 256 return PEOF; 257 flushout(&output); 258 flushout(&errout); 259 260 again: 261 if (parselleft <= 0) { 262 if ((parselleft = preadfd()) == -1) { 263 parselleft = parsenleft = EOF_NLEFT; 264 return PEOF; 265 } 266 } 267 268 /* p = (not const char *)parsenextc; */ 269 p = parsefile->buf + (parsenextc - parsefile->buf); 270 q = p; 271 272 /* delete nul characters */ 273 #ifndef SMALL 274 something = 0; 275 #endif 276 for (more = 1; more;) { 277 switch (*p) { 278 case '\0': 279 p++; /* Skip nul */ 280 goto check; 281 282 case '\t': 283 case ' ': 284 break; 285 286 case '\n': 287 parsenleft = q - parsenextc; 288 more = 0; /* Stop processing here */ 289 break; 290 291 default: 292 #ifndef SMALL 293 something = 1; 294 #endif 295 break; 296 } 297 298 *q++ = *p++; 299 check: 300 if (--parselleft <= 0) { 301 parsenleft = q - parsenextc - 1; 302 if (parsenleft < 0) 303 goto again; 304 *q = '\0'; 305 more = 0; 306 } 307 } 308 309 savec = *q; 310 *q = '\0'; 311 312 #ifndef SMALL 313 if (parsefile->fd == 0 && hist && (something || whichprompt == 2)) { 314 HistEvent he; 315 316 INTOFF; 317 history(hist, &he, whichprompt != 2 ? H_ENTER : H_APPEND, 318 parsenextc); 319 INTON; 320 } 321 #endif 322 323 if (vflag) { 324 out2str(parsenextc); 325 flushout(out2); 326 } 327 328 *q = savec; 329 330 return *parsenextc++; 331 } 332 333 /* 334 * Undo the last call to pgetc. Only one character may be pushed back. 335 * PEOF may be pushed back. 336 */ 337 338 void 339 pungetc(void) 340 { 341 parsenleft++; 342 parsenextc--; 343 } 344 345 /* 346 * Push a string back onto the input at this current parsefile level. 347 * We handle aliases this way. 348 */ 349 void 350 pushstring(const char *s, int len, struct alias *ap) 351 { 352 struct strpush *sp; 353 354 VTRACE(DBG_INPUT, 355 ("pushstring(\"%.*s\", %d)%s%s%s had: nl=%d ll=%d \"%.*s\"\n", 356 len, s, len, ap ? " for alias:'" : "", 357 ap ? ap->name : "", ap ? "'" : "", 358 parsenleft, parselleft, parsenleft, parsenextc)); 359 360 INTOFF; 361 if (parsefile->strpush) { 362 sp = ckmalloc(sizeof (struct strpush)); 363 sp->prev = parsefile->strpush; 364 parsefile->strpush = sp; 365 } else 366 sp = parsefile->strpush = &(parsefile->basestrpush); 367 368 sp->prevstring = parsenextc; 369 sp->prevnleft = parsenleft; 370 sp->prevlleft = parselleft; 371 sp->ap = ap; 372 if (ap) 373 ap->flag |= ALIASINUSE; 374 parsenextc = s; 375 parsenleft = len; 376 INTON; 377 } 378 379 void 380 popstring(void) 381 { 382 struct strpush *sp = parsefile->strpush; 383 384 INTOFF; 385 parsenextc = sp->prevstring; 386 parsenleft = sp->prevnleft; 387 parselleft = sp->prevlleft; 388 389 VTRACE(DBG_INPUT, ("popstring()%s%s%s nl=%d ll=%d \"%.*s\"\n", 390 sp->ap ? " from alias:'" : "", sp->ap ? sp->ap->name : "", 391 sp->ap ? "'" : "", parsenleft, parselleft, parsenleft, parsenextc)); 392 393 if (sp->ap) 394 sp->ap->flag &= ~ALIASINUSE; 395 parsefile->strpush = sp->prev; 396 if (sp != &(parsefile->basestrpush)) 397 ckfree(sp); 398 INTON; 399 } 400 401 /* 402 * Set the input to take input from a file. If push is set, push the 403 * old input onto the stack first. 404 */ 405 406 void 407 setinputfile(const char *fname, int push) 408 { 409 unsigned char magic[4]; 410 int fd; 411 int fd2; 412 struct stat sb; 413 414 CTRACE(DBG_INPUT,("setinputfile(\"%s\", %spush)\n",fname,push?"":"no")); 415 416 INTOFF; 417 if ((fd = open(fname, O_RDONLY)) < 0) 418 error("Can't open %s", fname); 419 420 /* Since the message "Syntax error: "(" unexpected" is not very 421 * helpful, we check if the file starts with the ELF magic to 422 * avoid that message. The first lseek tries to make sure that 423 * we can later rewind the file. 424 */ 425 if (fstat(fd, &sb) == 0 && S_ISREG(sb.st_mode) && 426 lseek(fd, 0, SEEK_SET) == 0) { 427 if (read(fd, magic, 4) == 4) { 428 if (memcmp(magic, "\177ELF", 4) == 0) { 429 (void)close(fd); 430 error("Cannot execute ELF binary %s", fname); 431 } 432 } 433 if (lseek(fd, 0, SEEK_SET) != 0) { 434 (void)close(fd); 435 error("Cannot rewind the file %s", fname); 436 } 437 } 438 439 fd2 = to_upper_fd(fd); /* closes fd, returns higher equiv */ 440 if (fd2 == fd) { 441 (void) close(fd); 442 error("Out of file descriptors"); 443 } 444 445 setinputfd(fd2, push); 446 INTON; 447 } 448 449 /* 450 * When a shell fd needs to be altered (when the user wants to use 451 * the same fd - rare, but happens - we need to locate the ref to 452 * the fd, and update it. This happens via a callback. 453 * This is the callback func for fd's used for shell input 454 */ 455 static void 456 input_fd_swap(int from, int to) 457 { 458 struct parsefile *pf; 459 460 pf = parsefile; 461 while (pf != NULL) { /* don't need to stop at basepf */ 462 if (pf->fd == from) 463 pf->fd = to; 464 pf = pf->prev; 465 } 466 } 467 468 /* 469 * Like setinputfile, but takes an open file descriptor. Call this with 470 * interrupts off. 471 */ 472 473 void 474 setinputfd(int fd, int push) 475 { 476 VTRACE(DBG_INPUT, ("setinputfd(%d, %spush)\n", fd, push?"":"no")); 477 478 register_sh_fd(fd, input_fd_swap); 479 (void) fcntl(fd, F_SETFD, FD_CLOEXEC); 480 if (push) 481 pushfile(); 482 if (parsefile->fd > 0) 483 sh_close(parsefile->fd); 484 parsefile->fd = fd; 485 if (parsefile->buf == NULL) 486 parsefile->buf = ckmalloc(BUFSIZ); 487 parselleft = parsenleft = 0; 488 plinno = 1; 489 490 CTRACE(DBG_INPUT, ("setinputfd(%d, %spush) done; plinno=1\n", fd, 491 push ? "" : "no")); 492 } 493 494 495 /* 496 * Like setinputfile, but takes input from a string. 497 */ 498 499 void 500 setinputstring(char *string, int push, int line1) 501 { 502 503 INTOFF; 504 if (push) /* XXX: always, as it happens */ 505 pushfile(); 506 parsenextc = string; 507 parselleft = parsenleft = strlen(string); 508 plinno = line1; 509 510 CTRACE(DBG_INPUT, 511 ("setinputstring(\"%.20s%s\" (%d), %spush, @ %d)\n", string, 512 (parsenleft > 20 ? "..." : ""), parsenleft, push?"":"no", line1)); 513 INTON; 514 } 515 516 517 518 /* 519 * To handle the "." command, a stack of input files is used. Pushfile 520 * adds a new entry to the stack and popfile restores the previous level. 521 */ 522 523 STATIC void 524 pushfile(void) 525 { 526 struct parsefile *pf; 527 528 VTRACE(DBG_INPUT, 529 ("pushfile(): fd=%d buf=%p nl=%d ll=%d \"%.*s\" plinno=%d\n", 530 parsefile->fd, parsefile->buf, parsenleft, parselleft, 531 parsenleft, parsenextc, plinno)); 532 533 parsefile->nleft = parsenleft; 534 parsefile->lleft = parselleft; 535 parsefile->nextc = parsenextc; 536 parsefile->linno = plinno; 537 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile)); 538 pf->prev = parsefile; 539 pf->fd = -1; 540 pf->strpush = NULL; 541 pf->basestrpush.prev = NULL; 542 pf->buf = NULL; 543 parsefile = pf; 544 } 545 546 547 void 548 popfile(void) 549 { 550 struct parsefile *pf = parsefile; 551 552 INTOFF; 553 if (pf->fd >= 0) 554 sh_close(pf->fd); 555 if (pf->buf) 556 ckfree(pf->buf); 557 while (pf->strpush) 558 popstring(); 559 parsefile = pf->prev; 560 ckfree(pf); 561 parsenleft = parsefile->nleft; 562 parselleft = parsefile->lleft; 563 parsenextc = parsefile->nextc; 564 565 VTRACE(DBG_INPUT, 566 ("popfile(): fd=%d buf=%p nl=%d ll=%d \"%.*s\" plinno:%d->%d\n", 567 parsefile->fd, parsefile->buf, parsenleft, parselleft, 568 parsenleft, parsenextc, plinno, parsefile->linno)); 569 570 plinno = parsefile->linno; 571 INTON; 572 } 573 574 /* 575 * Return current file (to go back to it later using popfilesupto()). 576 */ 577 578 struct parsefile * 579 getcurrentfile(void) 580 { 581 return parsefile; 582 } 583 584 585 /* 586 * Pop files until the given file is on top again. Useful for regular 587 * builtins that read shell commands from files or strings. 588 * If the given file is not an active file, an error is raised. 589 */ 590 591 void 592 popfilesupto(struct parsefile *file) 593 { 594 while (parsefile != file && parsefile != &basepf) 595 popfile(); 596 if (parsefile != file) 597 error("popfilesupto() misused"); 598 } 599 600 601 /* 602 * Return to top level. 603 */ 604 605 void 606 popallfiles(void) 607 { 608 while (parsefile != &basepf) 609 popfile(); 610 } 611 612 613 614 /* 615 * Close the file(s) that the shell is reading commands from. Called 616 * after a fork is done. 617 * 618 * Takes one arg, vfork, which tells it to not modify its global vars 619 * as it is still running in the parent. 620 * 621 * This code is (probably) unnecessary as the 'close on exec' flag is 622 * set and should be enough. In the vfork case it is definitely wrong 623 * to close the fds as another fork() may be done later to feed data 624 * from a 'here' document into a pipe and we don't want to close the 625 * pipe! 626 */ 627 628 void 629 closescript(int vforked) 630 { 631 if (vforked) 632 return; 633 popallfiles(); 634 if (parsefile->fd > 0) { 635 sh_close(parsefile->fd); 636 parsefile->fd = 0; 637 } 638 } 639