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 #include "myhistedit.h" 63 #include "trap.h" 64 65 #define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */ 66 67 struct strpush { 68 struct strpush *prev; /* preceding string on stack */ 69 const char *prevstring; 70 int prevnleft; 71 int prevlleft; 72 struct alias *ap; /* if push was associated with an alias */ 73 }; 74 75 /* 76 * The parsefile structure pointed to by the global variable parsefile 77 * contains information about the current file being read. 78 */ 79 80 struct parsefile { 81 struct parsefile *prev; /* preceding file on stack */ 82 int linno; /* current line */ 83 int fd; /* file descriptor (or -1 if string) */ 84 int nleft; /* number of chars left in this line */ 85 int lleft; /* number of lines left in this buffer */ 86 const char *nextc; /* next char in buffer */ 87 char *buf; /* input buffer */ 88 struct strpush *strpush; /* for pushing strings at this level */ 89 struct strpush basestrpush; /* so pushing one is fast */ 90 }; 91 92 93 int plinno = 1; /* input line number */ 94 int parsenleft; /* copy of parsefile->nleft */ 95 static int parselleft; /* copy of parsefile->lleft */ 96 const char *parsenextc; /* copy of parsefile->nextc */ 97 static char basebuf[BUFSIZ + 1];/* buffer for top level input file */ 98 static struct parsefile basepf = { /* top level input file */ 99 .nextc = basebuf, 100 .buf = basebuf 101 }; 102 static struct parsefile *parsefile = &basepf; /* current input file */ 103 int whichprompt; /* 1 == PS1, 2 == PS2 */ 104 105 static void pushfile(void); 106 static int preadfd(void); 107 static void popstring(void); 108 109 void 110 resetinput(void) 111 { 112 popallfiles(); 113 parselleft = parsenleft = 0; /* clear input buffer */ 114 } 115 116 117 118 /* 119 * Read a character from the script, returning PEOF on end of file. 120 * Nul characters in the input are silently discarded. 121 */ 122 123 int 124 pgetc(void) 125 { 126 return pgetc_macro(); 127 } 128 129 130 static int 131 preadfd(void) 132 { 133 int nr; 134 parsenextc = parsefile->buf; 135 136 retry: 137 #ifndef NO_HISTORY 138 if (parsefile->fd == 0 && el) { 139 static const char *rl_cp; 140 static int el_len; 141 142 if (rl_cp == NULL) { 143 el_resize(el); 144 rl_cp = el_gets(el, &el_len); 145 } 146 if (rl_cp == NULL) 147 nr = el_len == 0 ? 0 : -1; 148 else { 149 nr = el_len; 150 if (nr > BUFSIZ) 151 nr = BUFSIZ; 152 memcpy(parsefile->buf, rl_cp, nr); 153 if (nr != el_len) { 154 el_len -= nr; 155 rl_cp += nr; 156 } else 157 rl_cp = NULL; 158 } 159 } else 160 #endif 161 nr = read(parsefile->fd, parsefile->buf, BUFSIZ); 162 163 if (nr <= 0) { 164 if (nr < 0) { 165 if (errno == EINTR) 166 goto retry; 167 if (parsefile->fd == 0 && errno == EWOULDBLOCK) { 168 int flags = fcntl(0, F_GETFL, 0); 169 if (flags >= 0 && flags & O_NONBLOCK) { 170 flags &=~ O_NONBLOCK; 171 if (fcntl(0, F_SETFL, flags) >= 0) { 172 out2fmt_flush("sh: turning off NDELAY mode\n"); 173 goto retry; 174 } 175 } 176 } 177 } 178 nr = -1; 179 } 180 return nr; 181 } 182 183 /* 184 * Refill the input buffer and return the next input character: 185 * 186 * 1) If a string was pushed back on the input, pop it; 187 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading 188 * from a string so we can't refill the buffer, return EOF. 189 * 3) If there is more in this buffer, use it else call read to fill it. 190 * 4) Process input up to the next newline, deleting nul characters. 191 */ 192 193 int 194 preadbuffer(void) 195 { 196 char *p, *q, *r, *end; 197 char savec; 198 199 while (parsefile->strpush) { 200 /* 201 * Add a space to the end of an alias to ensure that the 202 * alias remains in use while parsing its last word. 203 * This avoids alias recursions. 204 */ 205 if (parsenleft == -1 && parsefile->strpush->ap != NULL) 206 return ' '; 207 popstring(); 208 if (--parsenleft >= 0) 209 return (*parsenextc++); 210 } 211 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 212 return PEOF; 213 214 again: 215 if (parselleft <= 0) { 216 if ((parselleft = preadfd()) == -1) { 217 parselleft = parsenleft = EOF_NLEFT; 218 return PEOF; 219 } 220 } 221 222 p = parsefile->buf + (parsenextc - parsefile->buf); 223 end = p + parselleft; 224 *end = '\0'; 225 q = strchrnul(p, '\n'); 226 if (q != end && *q == '\0') { 227 /* delete nul characters */ 228 for (r = q; q != end; q++) { 229 if (*q != '\0') 230 *r++ = *q; 231 } 232 parselleft -= end - r; 233 if (parselleft == 0) 234 goto again; 235 end = p + parselleft; 236 *end = '\0'; 237 q = strchrnul(p, '\n'); 238 } 239 if (q == end) { 240 parsenleft = parselleft; 241 parselleft = 0; 242 } else /* *q == '\n' */ { 243 q++; 244 parsenleft = q - parsenextc; 245 parselleft -= parsenleft; 246 } 247 parsenleft--; 248 249 savec = *q; 250 *q = '\0'; 251 252 #ifndef NO_HISTORY 253 if (parsefile->fd == 0 && hist && 254 parsenextc[strspn(parsenextc, " \t\n")] != '\0') { 255 HistEvent he; 256 INTOFF; 257 history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD, 258 parsenextc); 259 INTON; 260 } 261 #endif 262 263 if (vflag) { 264 out2str(parsenextc); 265 flushout(out2); 266 } 267 268 *q = savec; 269 270 return *parsenextc++; 271 } 272 273 /* 274 * Returns if we are certain we are at EOF. Does not cause any more input 275 * to be read from the outside world. 276 */ 277 278 int 279 preadateof(void) 280 { 281 if (parsenleft > 0) 282 return 0; 283 if (parsefile->strpush) 284 return 0; 285 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 286 return 1; 287 return 0; 288 } 289 290 /* 291 * Undo the last call to pgetc. Only one character may be pushed back. 292 * PEOF may be pushed back. 293 */ 294 295 void 296 pungetc(void) 297 { 298 parsenleft++; 299 parsenextc--; 300 } 301 302 /* 303 * Push a string back onto the input at this current parsefile level. 304 * We handle aliases this way. 305 */ 306 void 307 pushstring(const char *s, int len, struct alias *ap) 308 { 309 struct strpush *sp; 310 311 INTOFF; 312 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/ 313 if (parsefile->strpush) { 314 sp = ckmalloc(sizeof (struct strpush)); 315 sp->prev = parsefile->strpush; 316 parsefile->strpush = sp; 317 } else 318 sp = parsefile->strpush = &(parsefile->basestrpush); 319 sp->prevstring = parsenextc; 320 sp->prevnleft = parsenleft; 321 sp->prevlleft = parselleft; 322 sp->ap = ap; 323 if (ap) 324 ap->flag |= ALIASINUSE; 325 parsenextc = s; 326 parsenleft = len; 327 INTON; 328 } 329 330 static void 331 popstring(void) 332 { 333 struct strpush *sp = parsefile->strpush; 334 335 INTOFF; 336 if (sp->ap) { 337 if (parsenextc != sp->ap->val && 338 (parsenextc[-1] == ' ' || parsenextc[-1] == '\t')) 339 forcealias(); 340 sp->ap->flag &= ~ALIASINUSE; 341 } 342 parsenextc = sp->prevstring; 343 parsenleft = sp->prevnleft; 344 parselleft = sp->prevlleft; 345 /*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/ 346 parsefile->strpush = sp->prev; 347 if (sp != &(parsefile->basestrpush)) 348 ckfree(sp); 349 INTON; 350 } 351 352 /* 353 * Set the input to take input from a file. If push is set, push the 354 * old input onto the stack first. 355 */ 356 357 void 358 setinputfile(const char *fname, int push) 359 { 360 int e; 361 int fd; 362 int fd2; 363 364 INTOFF; 365 if ((fd = open(fname, O_RDONLY | O_CLOEXEC)) < 0) { 366 e = errno; 367 errorwithstatus(e == ENOENT || e == ENOTDIR ? 127 : 126, 368 "cannot open %s: %s", fname, strerror(e)); 369 } 370 if (fd < 10) { 371 fd2 = fcntl(fd, F_DUPFD_CLOEXEC, 10); 372 close(fd); 373 if (fd2 < 0) 374 error("Out of file descriptors"); 375 fd = fd2; 376 } 377 setinputfd(fd, push); 378 INTON; 379 } 380 381 382 /* 383 * Like setinputfile, but takes an open file descriptor (which should have 384 * its FD_CLOEXEC flag already set). Call this with interrupts off. 385 */ 386 387 void 388 setinputfd(int fd, int push) 389 { 390 if (push) { 391 pushfile(); 392 parsefile->buf = ckmalloc(BUFSIZ + 1); 393 } 394 if (parsefile->fd > 0) 395 close(parsefile->fd); 396 parsefile->fd = fd; 397 if (parsefile->buf == NULL) 398 parsefile->buf = ckmalloc(BUFSIZ + 1); 399 parselleft = parsenleft = 0; 400 plinno = 1; 401 } 402 403 404 /* 405 * Like setinputfile, but takes input from a string. 406 */ 407 408 void 409 setinputstring(const char *string, int push) 410 { 411 INTOFF; 412 if (push) 413 pushfile(); 414 parsenextc = string; 415 parselleft = parsenleft = strlen(string); 416 parsefile->buf = NULL; 417 plinno = 1; 418 INTON; 419 } 420 421 422 423 /* 424 * To handle the "." command, a stack of input files is used. Pushfile 425 * adds a new entry to the stack and popfile restores the previous level. 426 */ 427 428 static void 429 pushfile(void) 430 { 431 struct parsefile *pf; 432 433 parsefile->nleft = parsenleft; 434 parsefile->lleft = parselleft; 435 parsefile->nextc = parsenextc; 436 parsefile->linno = plinno; 437 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile)); 438 pf->prev = parsefile; 439 pf->fd = -1; 440 pf->strpush = NULL; 441 pf->basestrpush.prev = NULL; 442 parsefile = pf; 443 } 444 445 446 void 447 popfile(void) 448 { 449 struct parsefile *pf = parsefile; 450 451 INTOFF; 452 if (pf->fd >= 0) 453 close(pf->fd); 454 if (pf->buf) 455 ckfree(pf->buf); 456 while (pf->strpush) 457 popstring(); 458 parsefile = pf->prev; 459 ckfree(pf); 460 parsenleft = parsefile->nleft; 461 parselleft = parsefile->lleft; 462 parsenextc = parsefile->nextc; 463 plinno = parsefile->linno; 464 INTON; 465 } 466 467 468 /* 469 * Return current file (to go back to it later using popfilesupto()). 470 */ 471 472 struct parsefile * 473 getcurrentfile(void) 474 { 475 return parsefile; 476 } 477 478 479 /* 480 * Pop files until the given file is on top again. Useful for regular 481 * builtins that read shell commands from files or strings. 482 * If the given file is not an active file, an error is raised. 483 */ 484 485 void 486 popfilesupto(struct parsefile *file) 487 { 488 while (parsefile != file && parsefile != &basepf) 489 popfile(); 490 if (parsefile != file) 491 error("popfilesupto() misused"); 492 } 493 494 /* 495 * Return to top level. 496 */ 497 498 void 499 popallfiles(void) 500 { 501 while (parsefile != &basepf) 502 popfile(); 503 } 504 505 506 507 /* 508 * Close the file(s) that the shell is reading commands from. Called 509 * after a fork is done. 510 */ 511 512 void 513 closescript(void) 514 { 515 popallfiles(); 516 if (parsefile->fd > 0) { 517 close(parsefile->fd); 518 parsefile->fd = 0; 519 } 520 } 521