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 EditLine *el; /* cookie for editline package */ 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, *r, *end; 199 char savec; 200 201 while (parsefile->strpush) { 202 /* 203 * Add a space to the end of an alias to ensure that the 204 * alias remains in use while parsing its last word. 205 * This avoids alias recursions. 206 */ 207 if (parsenleft == -1 && parsefile->strpush->ap != NULL) 208 return ' '; 209 popstring(); 210 if (--parsenleft >= 0) 211 return (*parsenextc++); 212 } 213 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 214 return PEOF; 215 216 again: 217 if (parselleft <= 0) { 218 if ((parselleft = preadfd()) == -1) { 219 parselleft = parsenleft = EOF_NLEFT; 220 return PEOF; 221 } 222 } 223 224 p = parsefile->buf + (parsenextc - parsefile->buf); 225 end = p + parselleft; 226 *end = '\0'; 227 q = strchrnul(p, '\n'); 228 if (q != end && *q == '\0') { 229 /* delete nul characters */ 230 for (r = q; q != end; q++) { 231 if (*q != '\0') 232 *r++ = *q; 233 } 234 parselleft -= end - r; 235 if (parselleft == 0) 236 goto again; 237 end = p + parselleft; 238 *end = '\0'; 239 q = strchrnul(p, '\n'); 240 } 241 if (q == end) { 242 parsenleft = parselleft; 243 parselleft = 0; 244 } else /* *q == '\n' */ { 245 q++; 246 parsenleft = q - parsenextc; 247 parselleft -= parsenleft; 248 } 249 parsenleft--; 250 251 savec = *q; 252 *q = '\0'; 253 254 #ifndef NO_HISTORY 255 if (parsefile->fd == 0 && hist && 256 parsenextc[strspn(parsenextc, " \t\n")] != '\0') { 257 HistEvent he; 258 INTOFF; 259 history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD, 260 parsenextc); 261 INTON; 262 } 263 #endif 264 265 if (vflag) { 266 out2str(parsenextc); 267 flushout(out2); 268 } 269 270 *q = savec; 271 272 return *parsenextc++; 273 } 274 275 /* 276 * Returns if we are certain we are at EOF. Does not cause any more input 277 * to be read from the outside world. 278 */ 279 280 int 281 preadateof(void) 282 { 283 if (parsenleft > 0) 284 return 0; 285 if (parsefile->strpush) 286 return 0; 287 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 288 return 1; 289 return 0; 290 } 291 292 /* 293 * Undo the last call to pgetc. Only one character may be pushed back. 294 * PEOF may be pushed back. 295 */ 296 297 void 298 pungetc(void) 299 { 300 parsenleft++; 301 parsenextc--; 302 } 303 304 /* 305 * Push a string back onto the input at this current parsefile level. 306 * We handle aliases this way. 307 */ 308 void 309 pushstring(const char *s, int len, struct alias *ap) 310 { 311 struct strpush *sp; 312 313 INTOFF; 314 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/ 315 if (parsefile->strpush) { 316 sp = ckmalloc(sizeof (struct strpush)); 317 sp->prev = parsefile->strpush; 318 parsefile->strpush = sp; 319 } else 320 sp = parsefile->strpush = &(parsefile->basestrpush); 321 sp->prevstring = parsenextc; 322 sp->prevnleft = parsenleft; 323 sp->prevlleft = parselleft; 324 sp->ap = ap; 325 if (ap) 326 ap->flag |= ALIASINUSE; 327 parsenextc = s; 328 parsenleft = len; 329 INTON; 330 } 331 332 static void 333 popstring(void) 334 { 335 struct strpush *sp = parsefile->strpush; 336 337 INTOFF; 338 if (sp->ap) { 339 if (parsenextc != sp->ap->val && 340 (parsenextc[-1] == ' ' || parsenextc[-1] == '\t')) 341 forcealias(); 342 sp->ap->flag &= ~ALIASINUSE; 343 } 344 parsenextc = sp->prevstring; 345 parsenleft = sp->prevnleft; 346 parselleft = sp->prevlleft; 347 /*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/ 348 parsefile->strpush = sp->prev; 349 if (sp != &(parsefile->basestrpush)) 350 ckfree(sp); 351 INTON; 352 } 353 354 /* 355 * Set the input to take input from a file. If push is set, push the 356 * old input onto the stack first. 357 */ 358 359 void 360 setinputfile(const char *fname, int push) 361 { 362 int e; 363 int fd; 364 int fd2; 365 366 INTOFF; 367 if ((fd = open(fname, O_RDONLY | O_CLOEXEC)) < 0) { 368 e = errno; 369 errorwithstatus(e == ENOENT || e == ENOTDIR ? 127 : 126, 370 "cannot open %s: %s", fname, strerror(e)); 371 } 372 if (fd < 10) { 373 fd2 = fcntl(fd, F_DUPFD_CLOEXEC, 10); 374 close(fd); 375 if (fd2 < 0) 376 error("Out of file descriptors"); 377 fd = fd2; 378 } 379 setinputfd(fd, push); 380 INTON; 381 } 382 383 384 /* 385 * Like setinputfile, but takes an open file descriptor (which should have 386 * its FD_CLOEXEC flag already set). Call this with interrupts off. 387 */ 388 389 void 390 setinputfd(int fd, int push) 391 { 392 if (push) { 393 pushfile(); 394 parsefile->buf = ckmalloc(BUFSIZ + 1); 395 } 396 if (parsefile->fd > 0) 397 close(parsefile->fd); 398 parsefile->fd = fd; 399 if (parsefile->buf == NULL) 400 parsefile->buf = ckmalloc(BUFSIZ + 1); 401 parselleft = parsenleft = 0; 402 plinno = 1; 403 } 404 405 406 /* 407 * Like setinputfile, but takes input from a string. 408 */ 409 410 void 411 setinputstring(const char *string, int push) 412 { 413 INTOFF; 414 if (push) 415 pushfile(); 416 parsenextc = string; 417 parselleft = parsenleft = strlen(string); 418 parsefile->buf = NULL; 419 plinno = 1; 420 INTON; 421 } 422 423 424 425 /* 426 * To handle the "." command, a stack of input files is used. Pushfile 427 * adds a new entry to the stack and popfile restores the previous level. 428 */ 429 430 static void 431 pushfile(void) 432 { 433 struct parsefile *pf; 434 435 parsefile->nleft = parsenleft; 436 parsefile->lleft = parselleft; 437 parsefile->nextc = parsenextc; 438 parsefile->linno = plinno; 439 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile)); 440 pf->prev = parsefile; 441 pf->fd = -1; 442 pf->strpush = NULL; 443 pf->basestrpush.prev = NULL; 444 parsefile = pf; 445 } 446 447 448 void 449 popfile(void) 450 { 451 struct parsefile *pf = parsefile; 452 453 INTOFF; 454 if (pf->fd >= 0) 455 close(pf->fd); 456 if (pf->buf) 457 ckfree(pf->buf); 458 while (pf->strpush) 459 popstring(); 460 parsefile = pf->prev; 461 ckfree(pf); 462 parsenleft = parsefile->nleft; 463 parselleft = parsefile->lleft; 464 parsenextc = parsefile->nextc; 465 plinno = parsefile->linno; 466 INTON; 467 } 468 469 470 /* 471 * Return current file (to go back to it later using popfilesupto()). 472 */ 473 474 struct parsefile * 475 getcurrentfile(void) 476 { 477 return parsefile; 478 } 479 480 481 /* 482 * Pop files until the given file is on top again. Useful for regular 483 * builtins that read shell commands from files or strings. 484 * If the given file is not an active file, an error is raised. 485 */ 486 487 void 488 popfilesupto(struct parsefile *file) 489 { 490 while (parsefile != file && parsefile != &basepf) 491 popfile(); 492 if (parsefile != file) 493 error("popfilesupto() misused"); 494 } 495 496 /* 497 * Return to top level. 498 */ 499 500 void 501 popallfiles(void) 502 { 503 while (parsefile != &basepf) 504 popfile(); 505 } 506 507 508 509 /* 510 * Close the file(s) that the shell is reading commands from. Called 511 * after a fork is done. 512 */ 513 514 void 515 closescript(void) 516 { 517 popallfiles(); 518 if (parsefile->fd > 0) { 519 close(parsefile->fd); 520 parsefile->fd = 0; 521 } 522 } 523