1 /*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kenneth Almquist. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #ifndef lint 34 #if 0 35 static char sccsid[] = "@(#)input.c 8.3 (Berkeley) 6/9/95"; 36 #endif 37 #endif /* not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include <stdio.h> /* defines BUFSIZ */ 42 #include <fcntl.h> 43 #include <errno.h> 44 #include <unistd.h> 45 #include <stdlib.h> 46 #include <string.h> 47 48 /* 49 * This file implements the input routines used by the parser. 50 */ 51 52 #include "shell.h" 53 #include "redir.h" 54 #include "syntax.h" 55 #include "input.h" 56 #include "output.h" 57 #include "options.h" 58 #include "memalloc.h" 59 #include "error.h" 60 #include "alias.h" 61 #include "parser.h" 62 #ifndef NO_HISTORY 63 #include "myhistedit.h" 64 #endif 65 #include "trap.h" 66 67 #define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */ 68 69 struct strpush { 70 struct strpush *prev; /* preceding string on stack */ 71 const char *prevstring; 72 int prevnleft; 73 int prevlleft; 74 struct alias *ap; /* if push was associated with an alias */ 75 }; 76 77 /* 78 * The parsefile structure pointed to by the global variable parsefile 79 * contains information about the current file being read. 80 */ 81 82 struct parsefile { 83 struct parsefile *prev; /* preceding file on stack */ 84 int linno; /* current line */ 85 int fd; /* file descriptor (or -1 if string) */ 86 int nleft; /* number of chars left in this line */ 87 int lleft; /* number of lines left in this buffer */ 88 const char *nextc; /* next char in buffer */ 89 char *buf; /* input buffer */ 90 struct strpush *strpush; /* for pushing strings at this level */ 91 struct strpush basestrpush; /* so pushing one is fast */ 92 }; 93 94 95 int plinno = 1; /* input line number */ 96 int parsenleft; /* copy of parsefile->nleft */ 97 static int parselleft; /* copy of parsefile->lleft */ 98 const char *parsenextc; /* copy of parsefile->nextc */ 99 static char basebuf[BUFSIZ + 1];/* buffer for top level input file */ 100 static struct parsefile basepf = { /* top level input file */ 101 .nextc = basebuf, 102 .buf = basebuf 103 }; 104 static struct parsefile *parsefile = &basepf; /* current input file */ 105 int whichprompt; /* 1 == PS1, 2 == PS2 */ 106 107 static void pushfile(void); 108 static int preadfd(void); 109 static void popstring(void); 110 111 void 112 resetinput(void) 113 { 114 popallfiles(); 115 parselleft = parsenleft = 0; /* clear input buffer */ 116 } 117 118 119 120 /* 121 * Read a character from the script, returning PEOF on end of file. 122 * Nul characters in the input are silently discarded. 123 */ 124 125 int 126 pgetc(void) 127 { 128 return pgetc_macro(); 129 } 130 131 132 static int 133 preadfd(void) 134 { 135 int nr; 136 parsenextc = parsefile->buf; 137 138 retry: 139 #ifndef NO_HISTORY 140 if (parsefile->fd == 0 && el) { 141 static const char *rl_cp; 142 static int el_len; 143 144 if (rl_cp == NULL) { 145 el_resize(el); 146 rl_cp = el_gets(el, &el_len); 147 } 148 if (rl_cp == NULL) 149 nr = el_len == 0 ? 0 : -1; 150 else { 151 nr = el_len; 152 if (nr > BUFSIZ) 153 nr = BUFSIZ; 154 memcpy(parsefile->buf, rl_cp, nr); 155 if (nr != el_len) { 156 el_len -= nr; 157 rl_cp += nr; 158 } else 159 rl_cp = NULL; 160 } 161 } else 162 #endif 163 nr = read(parsefile->fd, parsefile->buf, BUFSIZ); 164 165 if (nr <= 0) { 166 if (nr < 0) { 167 if (errno == EINTR) 168 goto retry; 169 if (parsefile->fd == 0 && errno == EWOULDBLOCK) { 170 int flags = fcntl(0, F_GETFL, 0); 171 if (flags >= 0 && flags & O_NONBLOCK) { 172 flags &=~ O_NONBLOCK; 173 if (fcntl(0, F_SETFL, flags) >= 0) { 174 out2fmt_flush("sh: turning off NDELAY mode\n"); 175 goto retry; 176 } 177 } 178 } 179 } 180 nr = -1; 181 } 182 return nr; 183 } 184 185 /* 186 * Refill the input buffer and return the next input character: 187 * 188 * 1) If a string was pushed back on the input, pop it; 189 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading 190 * from a string so we can't refill the buffer, return EOF. 191 * 3) If there is more in this buffer, use it else call read to fill it. 192 * 4) Process input up to the next newline, deleting nul characters. 193 */ 194 195 int 196 preadbuffer(void) 197 { 198 char *p, *q; 199 int more; 200 char savec; 201 202 while (parsefile->strpush) { 203 /* 204 * Add a space to the end of an alias to ensure that the 205 * alias remains in use while parsing its last word. 206 * This avoids alias recursions. 207 */ 208 if (parsenleft == -1 && parsefile->strpush->ap != NULL) 209 return ' '; 210 popstring(); 211 if (--parsenleft >= 0) 212 return (*parsenextc++); 213 } 214 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 215 return PEOF; 216 flushout(&output); 217 flushout(&errout); 218 219 again: 220 if (parselleft <= 0) { 221 if ((parselleft = preadfd()) == -1) { 222 parselleft = parsenleft = EOF_NLEFT; 223 return PEOF; 224 } 225 } 226 227 q = p = parsefile->buf + (parsenextc - parsefile->buf); 228 229 /* delete nul characters */ 230 for (more = 1; more;) { 231 switch (*p) { 232 case '\0': 233 p++; /* Skip nul */ 234 goto check; 235 236 case '\n': 237 parsenleft = q - parsenextc; 238 more = 0; /* Stop processing here */ 239 break; 240 241 default: 242 break; 243 } 244 245 *q++ = *p++; 246 check: 247 if (--parselleft <= 0) { 248 parsenleft = q - parsenextc - 1; 249 if (parsenleft < 0) 250 goto again; 251 *q = '\0'; 252 more = 0; 253 } 254 } 255 256 savec = *q; 257 *q = '\0'; 258 259 #ifndef NO_HISTORY 260 if (parsefile->fd == 0 && hist && 261 parsenextc[strspn(parsenextc, " \t\n")] != '\0') { 262 HistEvent he; 263 INTOFF; 264 history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD, 265 parsenextc); 266 INTON; 267 } 268 #endif 269 270 if (vflag) { 271 out2str(parsenextc); 272 flushout(out2); 273 } 274 275 *q = savec; 276 277 return *parsenextc++; 278 } 279 280 /* 281 * Returns if we are certain we are at EOF. Does not cause any more input 282 * to be read from the outside world. 283 */ 284 285 int 286 preadateof(void) 287 { 288 if (parsenleft > 0) 289 return 0; 290 if (parsefile->strpush) 291 return 0; 292 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 293 return 1; 294 return 0; 295 } 296 297 /* 298 * Undo the last call to pgetc. Only one character may be pushed back. 299 * PEOF may be pushed back. 300 */ 301 302 void 303 pungetc(void) 304 { 305 parsenleft++; 306 parsenextc--; 307 } 308 309 /* 310 * Push a string back onto the input at this current parsefile level. 311 * We handle aliases this way. 312 */ 313 void 314 pushstring(const char *s, int len, struct alias *ap) 315 { 316 struct strpush *sp; 317 318 INTOFF; 319 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/ 320 if (parsefile->strpush) { 321 sp = ckmalloc(sizeof (struct strpush)); 322 sp->prev = parsefile->strpush; 323 parsefile->strpush = sp; 324 } else 325 sp = parsefile->strpush = &(parsefile->basestrpush); 326 sp->prevstring = parsenextc; 327 sp->prevnleft = parsenleft; 328 sp->prevlleft = parselleft; 329 sp->ap = ap; 330 if (ap) 331 ap->flag |= ALIASINUSE; 332 parsenextc = s; 333 parsenleft = len; 334 INTON; 335 } 336 337 static void 338 popstring(void) 339 { 340 struct strpush *sp = parsefile->strpush; 341 342 INTOFF; 343 if (sp->ap) { 344 if (parsenextc != sp->ap->val && 345 (parsenextc[-1] == ' ' || parsenextc[-1] == '\t')) 346 forcealias(); 347 sp->ap->flag &= ~ALIASINUSE; 348 } 349 parsenextc = sp->prevstring; 350 parsenleft = sp->prevnleft; 351 parselleft = sp->prevlleft; 352 /*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/ 353 parsefile->strpush = sp->prev; 354 if (sp != &(parsefile->basestrpush)) 355 ckfree(sp); 356 INTON; 357 } 358 359 /* 360 * Set the input to take input from a file. If push is set, push the 361 * old input onto the stack first. 362 */ 363 364 void 365 setinputfile(const char *fname, int push) 366 { 367 int fd; 368 int fd2; 369 370 INTOFF; 371 if ((fd = open(fname, O_RDONLY | O_CLOEXEC_MAYBE)) < 0) 372 error("cannot open %s: %s", fname, strerror(errno)); 373 if (fd < 10) { 374 fd2 = fcntl(fd, F_DUPFD_CLOEXEC_MAYBE, 10); 375 close(fd); 376 if (fd2 < 0) 377 error("Out of file descriptors"); 378 fd = fd2; 379 } 380 setinputfd(fd, push); 381 INTON; 382 } 383 384 385 /* 386 * Like setinputfile, but takes an open file descriptor (which should have 387 * its FD_CLOEXEC flag already set). Call this with interrupts off. 388 */ 389 390 void 391 setinputfd(int fd, int push) 392 { 393 #if !defined(O_CLOEXEC) || !defined(F_DUPFD_CLOEXEC) 394 fcntl(fd, F_SETFD, FD_CLOEXEC); 395 #endif 396 if (push) { 397 pushfile(); 398 parsefile->buf = ckmalloc(BUFSIZ + 1); 399 } 400 if (parsefile->fd > 0) 401 close(parsefile->fd); 402 parsefile->fd = fd; 403 if (parsefile->buf == NULL) 404 parsefile->buf = ckmalloc(BUFSIZ + 1); 405 parselleft = parsenleft = 0; 406 plinno = 1; 407 } 408 409 410 /* 411 * Like setinputfile, but takes input from a string. 412 */ 413 414 void 415 setinputstring(const char *string, int push) 416 { 417 INTOFF; 418 if (push) 419 pushfile(); 420 parsenextc = string; 421 parselleft = parsenleft = strlen(string); 422 parsefile->buf = NULL; 423 plinno = 1; 424 INTON; 425 } 426 427 428 429 /* 430 * To handle the "." command, a stack of input files is used. Pushfile 431 * adds a new entry to the stack and popfile restores the previous level. 432 */ 433 434 static void 435 pushfile(void) 436 { 437 struct parsefile *pf; 438 439 parsefile->nleft = parsenleft; 440 parsefile->lleft = parselleft; 441 parsefile->nextc = parsenextc; 442 parsefile->linno = plinno; 443 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile)); 444 pf->prev = parsefile; 445 pf->fd = -1; 446 pf->strpush = NULL; 447 pf->basestrpush.prev = NULL; 448 parsefile = pf; 449 } 450 451 452 void 453 popfile(void) 454 { 455 struct parsefile *pf = parsefile; 456 457 INTOFF; 458 if (pf->fd >= 0) 459 close(pf->fd); 460 if (pf->buf) 461 ckfree(pf->buf); 462 while (pf->strpush) 463 popstring(); 464 parsefile = pf->prev; 465 ckfree(pf); 466 parsenleft = parsefile->nleft; 467 parselleft = parsefile->lleft; 468 parsenextc = parsefile->nextc; 469 plinno = parsefile->linno; 470 INTON; 471 } 472 473 474 /* 475 * Return current file (to go back to it later using popfilesupto()). 476 */ 477 478 struct parsefile * 479 getcurrentfile(void) 480 { 481 return parsefile; 482 } 483 484 485 /* 486 * Pop files until the given file is on top again. Useful for regular 487 * builtins that read shell commands from files or strings. 488 * If the given file is not an active file, an error is raised. 489 */ 490 491 void 492 popfilesupto(struct parsefile *file) 493 { 494 while (parsefile != file && parsefile != &basepf) 495 popfile(); 496 if (parsefile != file) 497 error("popfilesupto() misused"); 498 } 499 500 /* 501 * Return to top level. 502 */ 503 504 void 505 popallfiles(void) 506 { 507 while (parsefile != &basepf) 508 popfile(); 509 } 510 511 512 513 /* 514 * Close the file(s) that the shell is reading commands from. Called 515 * after a fork is done. 516 */ 517 518 void 519 closescript(void) 520 { 521 popallfiles(); 522 if (parsefile->fd > 0) { 523 close(parsefile->fd); 524 parsefile->fd = 0; 525 } 526 } 527