1 /* $NetBSD: input.c,v 1.51 2016/06/01 05:11:52 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 1.51 2016/06/01 05:11:52 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 71 MKINIT 72 struct strpush { 73 struct strpush *prev; /* preceding string on stack */ 74 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 85 MKINIT 86 struct 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 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 99 int plinno = 1; /* input line number */ 100 int parsenleft; /* copy of parsefile->nleft */ 101 MKINIT int parselleft; /* copy of parsefile->lleft */ 102 char *parsenextc; /* copy of parsefile->nextc */ 103 MKINIT struct parsefile basepf; /* top level input file */ 104 MKINIT char basebuf[BUFSIZ]; /* buffer for top level input file */ 105 struct parsefile *parsefile = &basepf; /* current input file */ 106 int init_editline = 0; /* editline library initialized? */ 107 int whichprompt; /* 1 == PS1, 2 == PS2 */ 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 = 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 */ 236 237 int 238 preadbuffer(void) 239 { 240 char *p, *q; 241 int more; 242 #ifndef SMALL 243 int something; 244 #endif 245 char savec; 246 247 if (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); 256 257 again: 258 if (parselleft <= 0) { 259 if ((parselleft = preadfd()) == -1) { 260 parselleft = parsenleft = EOF_NLEFT; 261 return PEOF; 262 } 263 } 264 265 q = p = parsenextc; 266 267 /* delete nul characters */ 268 #ifndef SMALL 269 something = 0; 270 #endif 271 for (more = 1; more;) { 272 switch (*p) { 273 case '\0': 274 p++; /* Skip nul */ 275 goto check; 276 277 case '\t': 278 case ' ': 279 break; 280 281 case '\n': 282 parsenleft = q - parsenextc; 283 more = 0; /* Stop processing here */ 284 break; 285 286 default: 287 #ifndef SMALL 288 something = 1; 289 #endif 290 break; 291 } 292 293 *q++ = *p++; 294 check: 295 if (--parselleft <= 0) { 296 parsenleft = q - parsenextc - 1; 297 if (parsenleft < 0) 298 goto again; 299 *q = '\0'; 300 more = 0; 301 } 302 } 303 304 savec = *q; 305 *q = '\0'; 306 307 #ifndef SMALL 308 if (parsefile->fd == 0 && hist && something) { 309 HistEvent he; 310 INTOFF; 311 history(hist, &he, whichprompt == 1? H_ENTER : H_APPEND, 312 parsenextc); 313 INTON; 314 } 315 #endif 316 317 if (vflag) { 318 out2str(parsenextc); 319 flushout(out2); 320 } 321 322 *q = savec; 323 324 return *parsenextc++; 325 } 326 327 /* 328 * Undo the last call to pgetc. Only one character may be pushed back. 329 * PEOF may be pushed back. 330 */ 331 332 void 333 pungetc(void) 334 { 335 parsenleft++; 336 parsenextc--; 337 } 338 339 /* 340 * Push a string back onto the input at this current parsefile level. 341 * We handle aliases this way. 342 */ 343 void 344 pushstring(char *s, int len, void *ap) 345 { 346 struct strpush *sp; 347 348 INTOFF; 349 /*debugprintf("*** calling pushstring: %s, %d\n", s, len);*/ 350 if (parsefile->strpush) { 351 sp = ckmalloc(sizeof (struct strpush)); 352 sp->prev = parsefile->strpush; 353 parsefile->strpush = sp; 354 } else 355 sp = parsefile->strpush = &(parsefile->basestrpush); 356 sp->prevstring = parsenextc; 357 sp->prevnleft = parsenleft; 358 sp->prevlleft = parselleft; 359 sp->ap = (struct alias *)ap; 360 if (ap) 361 ((struct alias *)ap)->flag |= ALIASINUSE; 362 parsenextc = s; 363 parsenleft = len; 364 INTON; 365 } 366 367 void 368 popstring(void) 369 { 370 struct strpush *sp = parsefile->strpush; 371 372 INTOFF; 373 parsenextc = sp->prevstring; 374 parsenleft = sp->prevnleft; 375 parselleft = sp->prevlleft; 376 /*debugprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/ 377 if (sp->ap) 378 sp->ap->flag &= ~ALIASINUSE; 379 parsefile->strpush = sp->prev; 380 if (sp != &(parsefile->basestrpush)) 381 ckfree(sp); 382 INTON; 383 } 384 385 /* 386 * Set the input to take input from a file. If push is set, push the 387 * old input onto the stack first. 388 */ 389 390 void 391 setinputfile(const char *fname, int push) 392 { 393 unsigned char magic[4]; 394 int fd; 395 int fd2; 396 struct stat sb; 397 398 INTOFF; 399 if ((fd = open(fname, O_RDONLY)) < 0) 400 error("Can't open %s", fname); 401 402 /* Since the message "Syntax error: "(" unexpected" is not very 403 * helpful, we check if the file starts with the ELF magic to 404 * avoid that message. The first lseek tries to make sure that 405 * we can later rewind the file. 406 */ 407 if (fstat(fd, &sb) == 0 && S_ISREG(sb.st_mode) && 408 lseek(fd, 0, SEEK_SET) == 0) { 409 if (read(fd, magic, 4) == 4) { 410 if (memcmp(magic, "\177ELF", 4) == 0) { 411 (void)close(fd); 412 error("Cannot execute ELF binary %s", fname); 413 } 414 } 415 if (lseek(fd, 0, SEEK_SET) != 0) { 416 (void)close(fd); 417 error("Cannot rewind the file %s", fname); 418 } 419 } 420 421 fd2 = to_upper_fd(fd); /* closes fd, returns higher equiv */ 422 if (fd2 == fd) { 423 (void) close(fd); 424 error("Out of file descriptors"); 425 } 426 427 setinputfd(fd2, push); 428 INTON; 429 } 430 431 432 /* 433 * Like setinputfile, but takes an open file descriptor. Call this with 434 * interrupts off. 435 */ 436 437 void 438 setinputfd(int fd, int push) 439 { 440 (void) fcntl(fd, F_SETFD, FD_CLOEXEC); 441 if (push) { 442 pushfile(); 443 parsefile->buf = ckmalloc(BUFSIZ); 444 } 445 if (parsefile->fd > 0) 446 close(parsefile->fd); 447 parsefile->fd = fd; 448 if (parsefile->buf == NULL) 449 parsefile->buf = ckmalloc(BUFSIZ); 450 parselleft = parsenleft = 0; 451 plinno = 1; 452 } 453 454 455 /* 456 * Like setinputfile, but takes input from a string. 457 */ 458 459 void 460 setinputstring(char *string, int push) 461 { 462 463 INTOFF; 464 if (push) 465 pushfile(); 466 parsenextc = string; 467 parselleft = parsenleft = strlen(string); 468 parsefile->buf = NULL; 469 plinno = 1; 470 INTON; 471 } 472 473 474 475 /* 476 * To handle the "." command, a stack of input files is used. Pushfile 477 * adds a new entry to the stack and popfile restores the previous level. 478 */ 479 480 STATIC void 481 pushfile(void) 482 { 483 struct parsefile *pf; 484 485 parsefile->nleft = parsenleft; 486 parsefile->lleft = parselleft; 487 parsefile->nextc = parsenextc; 488 parsefile->linno = plinno; 489 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile)); 490 pf->prev = parsefile; 491 pf->fd = -1; 492 pf->strpush = NULL; 493 pf->basestrpush.prev = NULL; 494 parsefile = pf; 495 } 496 497 498 void 499 popfile(void) 500 { 501 struct parsefile *pf = parsefile; 502 503 INTOFF; 504 if (pf->fd >= 0) 505 close(pf->fd); 506 if (pf->buf) 507 ckfree(pf->buf); 508 while (pf->strpush) 509 popstring(); 510 parsefile = pf->prev; 511 ckfree(pf); 512 parsenleft = parsefile->nleft; 513 parselleft = parsefile->lleft; 514 parsenextc = parsefile->nextc; 515 plinno = parsefile->linno; 516 INTON; 517 } 518 519 520 /* 521 * Return to top level. 522 */ 523 524 void 525 popallfiles(void) 526 { 527 while (parsefile != &basepf) 528 popfile(); 529 } 530 531 532 533 /* 534 * Close the file(s) that the shell is reading commands from. Called 535 * after a fork is done. 536 * 537 * Takes one arg, vfork, which tells it to not modify its global vars 538 * as it is still running in the parent. 539 * 540 * This code is (probably) unnecessary as the 'close on exec' flag is 541 * set and should be enough. In the vfork case it is definitely wrong 542 * to close the fds as another fork() may be done later to feed data 543 * from a 'here' document into a pipe and we don't want to close the 544 * pipe! 545 */ 546 547 void 548 closescript(int vforked) 549 { 550 if (vforked) 551 return; 552 popallfiles(); 553 if (parsefile->fd > 0) { 554 close(parsefile->fd); 555 parsefile->fd = 0; 556 } 557 } 558