input.c revision 1.59
1/* $NetBSD: input.c,v 1.59 2017/06/30 23:02:56 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 38static char sccsid[] = "@(#)input.c 8.3 (Berkeley) 6/9/95"; 39#else 40__RCSID("$NetBSD: input.c,v 1.59 2017/06/30 23:02:56 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 72MKINIT 73struct 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 86MKINIT 87struct 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 100int plinno = 1; /* input line number */ 101int parsenleft; /* copy of parsefile->nleft */ 102MKINIT int parselleft; /* copy of parsefile->lleft */ 103const char *parsenextc; /* copy of parsefile->nextc */ 104MKINIT struct parsefile basepf; /* top level input file */ 105MKINIT char basebuf[BUFSIZ]; /* buffer for top level input file */ 106struct parsefile *parsefile = &basepf; /* current input file */ 107int init_editline = 0; /* editline library initialized? */ 108int whichprompt; /* 1 == PS1, 2 == PS2 */ 109 110STATIC void pushfile(void); 111static int preadfd(void); 112 113#ifdef mkinit 114INCLUDE <stdio.h> 115INCLUDE "input.h" 116INCLUDE "error.h" 117 118INIT { 119 basepf.nextc = basepf.buf = basebuf; 120} 121 122RESET { 123 if (exception != EXSHELLPROC) 124 parselleft = parsenleft = 0; /* clear input buffer */ 125 popallfiles(); 126} 127 128SHELLPROC { 129 popallfiles(); 130} 131#endif 132 133 134/* 135 * Read a line from the script. 136 */ 137 138char * 139pfgets(char *line, int len) 140{ 141 char *p = line; 142 int nleft = len; 143 int c; 144 145 while (--nleft > 0) { 146 c = pgetc_macro(); 147 if (c == PEOF) { 148 if (p == line) 149 return NULL; 150 break; 151 } 152 *p++ = c; 153 if (c == '\n') 154 break; 155 } 156 *p = '\0'; 157 return line; 158} 159 160 161 162/* 163 * Read a character from the script, returning PEOF on end of file. 164 * Nul characters in the input are silently discarded. 165 */ 166 167int 168pgetc(void) 169{ 170 return pgetc_macro(); 171} 172 173 174static int 175preadfd(void) 176{ 177 int nr; 178 char *buf = parsefile->buf; 179 parsenextc = buf; 180 181retry: 182#ifndef SMALL 183 if (parsefile->fd == 0 && el) { 184 static const char *rl_cp; 185 static int el_len; 186 187 if (rl_cp == NULL) 188 rl_cp = el_gets(el, &el_len); 189 if (rl_cp == NULL) 190 nr = el_len == 0 ? 0 : -1; 191 else { 192 nr = el_len; 193 if (nr > BUFSIZ - 8) 194 nr = BUFSIZ - 8; 195 memcpy(buf, rl_cp, nr); 196 if (nr != el_len) { 197 el_len -= nr; 198 rl_cp += nr; 199 } else 200 rl_cp = 0; 201 } 202 203 } else 204#endif 205 nr = read(parsefile->fd, buf, BUFSIZ - 8); 206 207 208 if (nr <= 0) { 209 if (nr < 0) { 210 if (errno == EINTR) 211 goto retry; 212 if (parsefile->fd == 0 && errno == EWOULDBLOCK) { 213 int flags = fcntl(0, F_GETFL, 0); 214 if (flags >= 0 && flags & O_NONBLOCK) { 215 flags &=~ O_NONBLOCK; 216 if (fcntl(0, F_SETFL, flags) >= 0) { 217 out2str("sh: turning off NDELAY mode\n"); 218 goto retry; 219 } 220 } 221 } 222 } 223 nr = -1; 224 } 225 return nr; 226} 227 228/* 229 * Refill the input buffer and return the next input character: 230 * 231 * 1) If a string was pushed back on the input, pop it; 232 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading 233 * from a string so we can't refill the buffer, return EOF. 234 * 3) If the is more stuff in this buffer, use it else call read to fill it. 235 * 4) Process input up to the next newline, deleting nul characters. 236 */ 237 238int 239preadbuffer(void) 240{ 241 char *p, *q; 242 int more; 243#ifndef SMALL 244 int something; 245#endif 246 char savec; 247 248 while (parsefile->strpush) { 249 popstring(); 250 if (--parsenleft >= 0) 251 return (*parsenextc++); 252 } 253 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 254 return PEOF; 255 flushout(&output); 256 flushout(&errout); 257 258again: 259 if (parselleft <= 0) { 260 if ((parselleft = preadfd()) == -1) { 261 parselleft = parsenleft = EOF_NLEFT; 262 return PEOF; 263 } 264 } 265 266 /* p = (not const char *)parsenextc; */ 267 p = parsefile->buf + (parsenextc - parsefile->buf); 268 q = p; 269 270 /* delete nul characters */ 271#ifndef SMALL 272 something = 0; 273#endif 274 for (more = 1; more;) { 275 switch (*p) { 276 case '\0': 277 p++; /* Skip nul */ 278 goto check; 279 280 case '\t': 281 case ' ': 282 break; 283 284 case '\n': 285 parsenleft = q - parsenextc; 286 more = 0; /* Stop processing here */ 287 break; 288 289 default: 290#ifndef SMALL 291 something = 1; 292#endif 293 break; 294 } 295 296 *q++ = *p++; 297check: 298 if (--parselleft <= 0) { 299 parsenleft = q - parsenextc - 1; 300 if (parsenleft < 0) 301 goto again; 302 *q = '\0'; 303 more = 0; 304 } 305 } 306 307 savec = *q; 308 *q = '\0'; 309 310#ifndef SMALL 311 if (parsefile->fd == 0 && hist && something) { 312 HistEvent he; 313 INTOFF; 314 history(hist, &he, whichprompt == 1? H_ENTER : H_APPEND, 315 parsenextc); 316 INTON; 317 } 318#endif 319 320 if (vflag) { 321 out2str(parsenextc); 322 flushout(out2); 323 } 324 325 *q = savec; 326 327 return *parsenextc++; 328} 329 330/* 331 * Undo the last call to pgetc. Only one character may be pushed back. 332 * PEOF may be pushed back. 333 */ 334 335void 336pungetc(void) 337{ 338 parsenleft++; 339 parsenextc--; 340} 341 342/* 343 * Push a string back onto the input at this current parsefile level. 344 * We handle aliases this way. 345 */ 346void 347pushstring(const char *s, int len, struct alias *ap) 348{ 349 struct strpush *sp; 350 351 INTOFF; 352/*debugprintf("*** calling pushstring: %s, %d\n", s, len);*/ 353 if (parsefile->strpush) { 354 sp = ckmalloc(sizeof (struct strpush)); 355 sp->prev = parsefile->strpush; 356 parsefile->strpush = sp; 357 } else 358 sp = parsefile->strpush = &(parsefile->basestrpush); 359 sp->prevstring = parsenextc; 360 sp->prevnleft = parsenleft; 361 sp->prevlleft = parselleft; 362 sp->ap = ap; 363 if (ap) 364 ap->flag |= ALIASINUSE; 365 parsenextc = s; 366 parsenleft = len; 367 INTON; 368} 369 370void 371popstring(void) 372{ 373 struct strpush *sp = parsefile->strpush; 374 375 INTOFF; 376 parsenextc = sp->prevstring; 377 parsenleft = sp->prevnleft; 378 parselleft = sp->prevlleft; 379/*debugprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/ 380 if (sp->ap) 381 sp->ap->flag &= ~ALIASINUSE; 382 parsefile->strpush = sp->prev; 383 if (sp != &(parsefile->basestrpush)) 384 ckfree(sp); 385 INTON; 386} 387 388/* 389 * Set the input to take input from a file. If push is set, push the 390 * old input onto the stack first. 391 */ 392 393void 394setinputfile(const char *fname, int push) 395{ 396 unsigned char magic[4]; 397 int fd; 398 int fd2; 399 struct stat sb; 400 401 INTOFF; 402 if ((fd = open(fname, O_RDONLY)) < 0) 403 error("Can't open %s", fname); 404 405 /* Since the message "Syntax error: "(" unexpected" is not very 406 * helpful, we check if the file starts with the ELF magic to 407 * avoid that message. The first lseek tries to make sure that 408 * we can later rewind the file. 409 */ 410 if (fstat(fd, &sb) == 0 && S_ISREG(sb.st_mode) && 411 lseek(fd, 0, SEEK_SET) == 0) { 412 if (read(fd, magic, 4) == 4) { 413 if (memcmp(magic, "\177ELF", 4) == 0) { 414 (void)close(fd); 415 error("Cannot execute ELF binary %s", fname); 416 } 417 } 418 if (lseek(fd, 0, SEEK_SET) != 0) { 419 (void)close(fd); 420 error("Cannot rewind the file %s", fname); 421 } 422 } 423 424 fd2 = to_upper_fd(fd); /* closes fd, returns higher equiv */ 425 if (fd2 == fd) { 426 (void) close(fd); 427 error("Out of file descriptors"); 428 } 429 430 setinputfd(fd2, push); 431 INTON; 432} 433 434/* 435 * When a shell fd needs to be altered (when the user wants to use 436 * the same fd - rare, but happens - we need to locate the ref to 437 * the fd, and update it. This happens via a callback. 438 * This is the callback func for fd's used for shell input 439 */ 440static void 441input_fd_swap(int from, int to) 442{ 443 struct parsefile *pf; 444 445 pf = parsefile; 446 while (pf != NULL) { /* don't need to stop at basepf */ 447 if (pf->fd == from) 448 pf->fd = to; 449 pf = pf->prev; 450 } 451} 452 453/* 454 * Like setinputfile, but takes an open file descriptor. Call this with 455 * interrupts off. 456 */ 457 458void 459setinputfd(int fd, int push) 460{ 461 register_sh_fd(fd, input_fd_swap); 462 (void) fcntl(fd, F_SETFD, FD_CLOEXEC); 463 if (push) { 464 pushfile(); 465 parsefile->buf = ckmalloc(BUFSIZ); 466 } 467 if (parsefile->fd > 0) 468 sh_close(parsefile->fd); 469 parsefile->fd = fd; 470 if (parsefile->buf == NULL) 471 parsefile->buf = ckmalloc(BUFSIZ); 472 parselleft = parsenleft = 0; 473 plinno = 1; 474 CTRACE(DBG_INPUT, ("setinputfd(%d, %d); plinno=1\n", fd, push)); 475} 476 477 478/* 479 * Like setinputfile, but takes input from a string. 480 */ 481 482void 483setinputstring(char *string, int push, int line1) 484{ 485 486 INTOFF; 487 if (push) /* XXX: always, as it happens */ 488 pushfile(); 489 parsenextc = string; 490 parselleft = parsenleft = strlen(string); 491 parsefile->buf = NULL; 492 plinno = line1; 493 CTRACE(DBG_INPUT, ("setinputstring(\"%.20s%s\" (%d), %d, %d)\n", string, 494 (parsenleft > 20 ? "..." : ""), parsenleft, push, line1)); 495 INTON; 496} 497 498 499 500/* 501 * To handle the "." command, a stack of input files is used. Pushfile 502 * adds a new entry to the stack and popfile restores the previous level. 503 */ 504 505STATIC void 506pushfile(void) 507{ 508 struct parsefile *pf; 509 510 VTRACE(DBG_INPUT, ("pushfile(): fd=%d nl=%d ll=%d \"%.*s\" plinno=%d\n", 511 parsefile->fd, parsenleft, parselleft, 512 parsenleft, parsenextc, plinno)); 513 514 parsefile->nleft = parsenleft; 515 parsefile->lleft = parselleft; 516 parsefile->nextc = parsenextc; 517 parsefile->linno = plinno; 518 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile)); 519 pf->prev = parsefile; 520 pf->fd = -1; 521 pf->strpush = NULL; 522 pf->basestrpush.prev = NULL; 523 parsefile = pf; 524} 525 526 527void 528popfile(void) 529{ 530 struct parsefile *pf = parsefile; 531 532 INTOFF; 533 if (pf->fd >= 0) 534 sh_close(pf->fd); 535 if (pf->buf) 536 ckfree(pf->buf); 537 while (pf->strpush) 538 popstring(); 539 parsefile = pf->prev; 540 ckfree(pf); 541 parsenleft = parsefile->nleft; 542 parselleft = parsefile->lleft; 543 parsenextc = parsefile->nextc; 544 VTRACE(DBG_INPUT, 545 ("popfile(): fd=%d nl=%d ll=%d \"%.*s\" plinno:%d->%d\n", 546 parsefile->fd, parsenleft, parselleft, 547 parsenleft, parsenextc, plinno, parsefile->linno)); 548 plinno = parsefile->linno; 549 INTON; 550} 551 552/* 553 * Return current file (to go back to it later using popfilesupto()). 554 */ 555 556struct parsefile * 557getcurrentfile(void) 558{ 559 return parsefile; 560} 561 562 563/* 564 * Pop files until the given file is on top again. Useful for regular 565 * builtins that read shell commands from files or strings. 566 * If the given file is not an active file, an error is raised. 567 */ 568 569void 570popfilesupto(struct parsefile *file) 571{ 572 while (parsefile != file && parsefile != &basepf) 573 popfile(); 574 if (parsefile != file) 575 error("popfilesupto() misused"); 576} 577 578 579/* 580 * Return to top level. 581 */ 582 583void 584popallfiles(void) 585{ 586 while (parsefile != &basepf) 587 popfile(); 588} 589 590 591 592/* 593 * Close the file(s) that the shell is reading commands from. Called 594 * after a fork is done. 595 * 596 * Takes one arg, vfork, which tells it to not modify its global vars 597 * as it is still running in the parent. 598 * 599 * This code is (probably) unnecessary as the 'close on exec' flag is 600 * set and should be enough. In the vfork case it is definitely wrong 601 * to close the fds as another fork() may be done later to feed data 602 * from a 'here' document into a pipe and we don't want to close the 603 * pipe! 604 */ 605 606void 607closescript(int vforked) 608{ 609 if (vforked) 610 return; 611 popallfiles(); 612 if (parsefile->fd > 0) { 613 sh_close(parsefile->fd); 614 parsefile->fd = 0; 615 } 616} 617