input.c revision 1.56
1/* $NetBSD: input.c,v 1.56 2017/05/03 06:20:12 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 1.56 2017/05/03 06:20:12 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 69#define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */ 70 71MKINIT 72struct strpush { 73 struct strpush *prev; /* preceding string on stack */ 74 const char *prevstring; 75 int prevnleft; 76 int prevlleft; 77 struct alias *ap; /* if push was associated with an alias */ 78}; 79 80/* 81 * The parsefile structure pointed to by the global variable parsefile 82 * contains information about the current file being read. 83 */ 84 85MKINIT 86struct parsefile { 87 struct parsefile *prev; /* preceding file on stack */ 88 int linno; /* current line */ 89 int fd; /* file descriptor (or -1 if string) */ 90 int nleft; /* number of chars left in this line */ 91 int lleft; /* number of chars left in this buffer */ 92 const char *nextc; /* next char in buffer */ 93 char *buf; /* input buffer */ 94 struct strpush *strpush; /* for pushing strings at this level */ 95 struct strpush basestrpush; /* so pushing one is fast */ 96}; 97 98 99int plinno = 1; /* input line number */ 100int parsenleft; /* copy of parsefile->nleft */ 101MKINIT int parselleft; /* copy of parsefile->lleft */ 102const char *parsenextc; /* copy of parsefile->nextc */ 103MKINIT struct parsefile basepf; /* top level input file */ 104MKINIT char basebuf[BUFSIZ]; /* buffer for top level input file */ 105struct parsefile *parsefile = &basepf; /* current input file */ 106int init_editline = 0; /* editline library initialized? */ 107int whichprompt; /* 1 == PS1, 2 == PS2 */ 108 109STATIC void pushfile(void); 110static int preadfd(void); 111 112#ifdef mkinit 113INCLUDE <stdio.h> 114INCLUDE "input.h" 115INCLUDE "error.h" 116 117INIT { 118 basepf.nextc = basepf.buf = basebuf; 119} 120 121RESET { 122 if (exception != EXSHELLPROC) 123 parselleft = parsenleft = 0; /* clear input buffer */ 124 popallfiles(); 125} 126 127SHELLPROC { 128 popallfiles(); 129} 130#endif 131 132 133/* 134 * Read a line from the script. 135 */ 136 137char * 138pfgets(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 166int 167pgetc(void) 168{ 169 return pgetc_macro(); 170} 171 172 173static int 174preadfd(void) 175{ 176 int nr; 177 char *buf = parsefile->buf; 178 parsenextc = buf; 179 180retry: 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 = el_len == 0 ? 0 : -1; 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 237int 238preadbuffer(void) 239{ 240 char *p, *q; 241 int more; 242#ifndef SMALL 243 int something; 244#endif 245 char savec; 246 247 while (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 257again: 258 if (parselleft <= 0) { 259 if ((parselleft = preadfd()) == -1) { 260 parselleft = parsenleft = EOF_NLEFT; 261 return PEOF; 262 } 263 } 264 265 /* p = (not const char *)parsenextc; */ 266 p = parsefile->buf + (parsenextc - parsefile->buf); 267 q = p; 268 269 /* delete nul characters */ 270#ifndef SMALL 271 something = 0; 272#endif 273 for (more = 1; more;) { 274 switch (*p) { 275 case '\0': 276 p++; /* Skip nul */ 277 goto check; 278 279 case '\t': 280 case ' ': 281 break; 282 283 case '\n': 284 parsenleft = q - parsenextc; 285 more = 0; /* Stop processing here */ 286 break; 287 288 default: 289#ifndef SMALL 290 something = 1; 291#endif 292 break; 293 } 294 295 *q++ = *p++; 296check: 297 if (--parselleft <= 0) { 298 parsenleft = q - parsenextc - 1; 299 if (parsenleft < 0) 300 goto again; 301 *q = '\0'; 302 more = 0; 303 } 304 } 305 306 savec = *q; 307 *q = '\0'; 308 309#ifndef SMALL 310 if (parsefile->fd == 0 && hist && something) { 311 HistEvent he; 312 INTOFF; 313 history(hist, &he, whichprompt == 1? H_ENTER : H_APPEND, 314 parsenextc); 315 INTON; 316 } 317#endif 318 319 if (vflag) { 320 out2str(parsenextc); 321 flushout(out2); 322 } 323 324 *q = savec; 325 326 return *parsenextc++; 327} 328 329/* 330 * Undo the last call to pgetc. Only one character may be pushed back. 331 * PEOF may be pushed back. 332 */ 333 334void 335pungetc(void) 336{ 337 parsenleft++; 338 parsenextc--; 339} 340 341/* 342 * Push a string back onto the input at this current parsefile level. 343 * We handle aliases this way. 344 */ 345void 346pushstring(const char *s, int len, struct alias *ap) 347{ 348 struct strpush *sp; 349 350 INTOFF; 351/*debugprintf("*** calling pushstring: %s, %d\n", s, len);*/ 352 if (parsefile->strpush) { 353 sp = ckmalloc(sizeof (struct strpush)); 354 sp->prev = parsefile->strpush; 355 parsefile->strpush = sp; 356 } else 357 sp = parsefile->strpush = &(parsefile->basestrpush); 358 sp->prevstring = parsenextc; 359 sp->prevnleft = parsenleft; 360 sp->prevlleft = parselleft; 361 sp->ap = ap; 362 if (ap) 363 ap->flag |= ALIASINUSE; 364 parsenextc = s; 365 parsenleft = len; 366 INTON; 367} 368 369void 370popstring(void) 371{ 372 struct strpush *sp = parsefile->strpush; 373 374 INTOFF; 375 parsenextc = sp->prevstring; 376 parsenleft = sp->prevnleft; 377 parselleft = sp->prevlleft; 378/*debugprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/ 379 if (sp->ap) 380 sp->ap->flag &= ~ALIASINUSE; 381 parsefile->strpush = sp->prev; 382 if (sp != &(parsefile->basestrpush)) 383 ckfree(sp); 384 INTON; 385} 386 387/* 388 * Set the input to take input from a file. If push is set, push the 389 * old input onto the stack first. 390 */ 391 392void 393setinputfile(const char *fname, int push) 394{ 395 unsigned char magic[4]; 396 int fd; 397 int fd2; 398 struct stat sb; 399 400 INTOFF; 401 if ((fd = open(fname, O_RDONLY)) < 0) 402 error("Can't open %s", fname); 403 404 /* Since the message "Syntax error: "(" unexpected" is not very 405 * helpful, we check if the file starts with the ELF magic to 406 * avoid that message. The first lseek tries to make sure that 407 * we can later rewind the file. 408 */ 409 if (fstat(fd, &sb) == 0 && S_ISREG(sb.st_mode) && 410 lseek(fd, 0, SEEK_SET) == 0) { 411 if (read(fd, magic, 4) == 4) { 412 if (memcmp(magic, "\177ELF", 4) == 0) { 413 (void)close(fd); 414 error("Cannot execute ELF binary %s", fname); 415 } 416 } 417 if (lseek(fd, 0, SEEK_SET) != 0) { 418 (void)close(fd); 419 error("Cannot rewind the file %s", fname); 420 } 421 } 422 423 fd2 = to_upper_fd(fd); /* closes fd, returns higher equiv */ 424 if (fd2 == fd) { 425 (void) close(fd); 426 error("Out of file descriptors"); 427 } 428 429 setinputfd(fd2, push); 430 INTON; 431} 432 433/* 434 * When a shell fd needs to be altered (when the user wants to use 435 * the same fd - rare, but happens - we need to locate the ref to 436 * the fd, and update it. This happens via a callback. 437 * This is the callback func for fd's used for shell input 438 */ 439static void 440input_fd_swap(int from, int to) 441{ 442 struct parsefile *pf; 443 444 pf = parsefile; 445 while (pf != NULL) { /* don't need to stop at basepf */ 446 if (pf->fd == from) 447 pf->fd = to; 448 pf = pf->prev; 449 } 450} 451 452/* 453 * Like setinputfile, but takes an open file descriptor. Call this with 454 * interrupts off. 455 */ 456 457void 458setinputfd(int fd, int push) 459{ 460 register_sh_fd(fd, input_fd_swap); 461 (void) fcntl(fd, F_SETFD, FD_CLOEXEC); 462 if (push) { 463 pushfile(); 464 parsefile->buf = ckmalloc(BUFSIZ); 465 } 466 if (parsefile->fd > 0) 467 sh_close(parsefile->fd); 468 parsefile->fd = fd; 469 if (parsefile->buf == NULL) 470 parsefile->buf = ckmalloc(BUFSIZ); 471 parselleft = parsenleft = 0; 472 plinno = 1; 473} 474 475 476/* 477 * Like setinputfile, but takes input from a string. 478 */ 479 480void 481setinputstring(char *string, int push) 482{ 483 484 INTOFF; 485 if (push) 486 pushfile(); 487 parsenextc = string; 488 parselleft = parsenleft = strlen(string); 489 parsefile->buf = NULL; 490 plinno = 1; 491 INTON; 492} 493 494 495 496/* 497 * To handle the "." command, a stack of input files is used. Pushfile 498 * adds a new entry to the stack and popfile restores the previous level. 499 */ 500 501STATIC void 502pushfile(void) 503{ 504 struct parsefile *pf; 505 506 parsefile->nleft = parsenleft; 507 parsefile->lleft = parselleft; 508 parsefile->nextc = parsenextc; 509 parsefile->linno = plinno; 510 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile)); 511 pf->prev = parsefile; 512 pf->fd = -1; 513 pf->strpush = NULL; 514 pf->basestrpush.prev = NULL; 515 parsefile = pf; 516} 517 518 519void 520popfile(void) 521{ 522 struct parsefile *pf = parsefile; 523 524 INTOFF; 525 if (pf->fd >= 0) 526 sh_close(pf->fd); 527 if (pf->buf) 528 ckfree(pf->buf); 529 while (pf->strpush) 530 popstring(); 531 parsefile = pf->prev; 532 ckfree(pf); 533 parsenleft = parsefile->nleft; 534 parselleft = parsefile->lleft; 535 parsenextc = parsefile->nextc; 536 plinno = parsefile->linno; 537 INTON; 538} 539 540 541/* 542 * Return to top level. 543 */ 544 545void 546popallfiles(void) 547{ 548 while (parsefile != &basepf) 549 popfile(); 550} 551 552 553 554/* 555 * Close the file(s) that the shell is reading commands from. Called 556 * after a fork is done. 557 * 558 * Takes one arg, vfork, which tells it to not modify its global vars 559 * as it is still running in the parent. 560 * 561 * This code is (probably) unnecessary as the 'close on exec' flag is 562 * set and should be enough. In the vfork case it is definitely wrong 563 * to close the fds as another fork() may be done later to feed data 564 * from a 'here' document into a pipe and we don't want to close the 565 * pipe! 566 */ 567 568void 569closescript(int vforked) 570{ 571 if (vforked) 572 return; 573 popallfiles(); 574 if (parsefile->fd > 0) { 575 sh_close(parsefile->fd); 576 parsefile->fd = 0; 577 } 578} 579