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 #include <stdio.h> /* defines BUFSIZ */ 34 #include <fcntl.h> 35 #include <errno.h> 36 #include <unistd.h> 37 #include <stdlib.h> 38 #include <string.h> 39 40 /* 41 * This file implements the input routines used by the parser. 42 */ 43 44 #include "shell.h" 45 #include "redir.h" 46 #include "syntax.h" 47 #include "input.h" 48 #include "output.h" 49 #include "options.h" 50 #include "memalloc.h" 51 #include "error.h" 52 #include "alias.h" 53 #include "parser.h" 54 #ifndef NO_HISTORY 55 #include "myhistedit.h" 56 #endif 57 #include "trap.h" 58 59 #define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */ 60 61 struct strpush { 62 struct strpush *prev; /* preceding string on stack */ 63 const char *prevstring; 64 int prevnleft; 65 int prevlleft; 66 struct alias *ap; /* if push was associated with an alias */ 67 }; 68 69 /* 70 * The parsefile structure pointed to by the global variable parsefile 71 * contains information about the current file being read. 72 */ 73 74 struct parsefile { 75 struct parsefile *prev; /* preceding file on stack */ 76 int linno; /* current line */ 77 int fd; /* file descriptor (or -1 if string) */ 78 int nleft; /* number of chars left in this line */ 79 int lleft; /* number of lines left in this buffer */ 80 const char *nextc; /* next char in buffer */ 81 char *buf; /* input buffer */ 82 struct strpush *strpush; /* for pushing strings at this level */ 83 struct strpush basestrpush; /* so pushing one is fast */ 84 }; 85 86 87 int plinno = 1; /* input line number */ 88 int parsenleft; /* copy of parsefile->nleft */ 89 static int parselleft; /* copy of parsefile->lleft */ 90 const char *parsenextc; /* copy of parsefile->nextc */ 91 static char basebuf[BUFSIZ + 1];/* buffer for top level input file */ 92 static struct parsefile basepf = { /* top level input file */ 93 .nextc = basebuf, 94 .buf = basebuf 95 }; 96 static struct parsefile *parsefile = &basepf; /* current input file */ 97 int whichprompt; /* 1 == PS1, 2 == PS2 */ 98 99 static void pushfile(void); 100 static int preadfd(void); 101 static void popstring(void); 102 103 void 104 resetinput(void) 105 { 106 popallfiles(); 107 parselleft = parsenleft = 0; /* clear input buffer */ 108 } 109 110 111 112 /* 113 * Read a character from the script, returning PEOF on end of file. 114 * Nul characters in the input are silently discarded. 115 */ 116 117 int 118 pgetc(void) 119 { 120 return pgetc_macro(); 121 } 122 123 124 static int 125 preadfd(void) 126 { 127 int nr; 128 parsenextc = parsefile->buf; 129 130 retry: 131 #ifndef NO_HISTORY 132 if (parsefile->fd == 0 && el) { 133 static const char *rl_cp; 134 static int el_len; 135 136 if (rl_cp == NULL) { 137 el_resize(el); 138 rl_cp = el_gets(el, &el_len); 139 } 140 if (rl_cp == NULL) 141 nr = el_len == 0 ? 0 : -1; 142 else { 143 nr = el_len; 144 if (nr > BUFSIZ) 145 nr = BUFSIZ; 146 memcpy(parsefile->buf, rl_cp, nr); 147 if (nr != el_len) { 148 el_len -= nr; 149 rl_cp += nr; 150 } else 151 rl_cp = NULL; 152 } 153 } else 154 #endif 155 nr = read(parsefile->fd, parsefile->buf, BUFSIZ); 156 157 if (nr <= 0) { 158 if (nr < 0) { 159 if (errno == EINTR) 160 goto retry; 161 if (parsefile->fd == 0 && errno == EWOULDBLOCK) { 162 int flags = fcntl(0, F_GETFL, 0); 163 if (flags >= 0 && flags & O_NONBLOCK) { 164 flags &=~ O_NONBLOCK; 165 if (fcntl(0, F_SETFL, flags) >= 0) { 166 out2fmt_flush("sh: turning off NDELAY mode\n"); 167 goto retry; 168 } 169 } 170 } 171 } 172 nr = -1; 173 } 174 return nr; 175 } 176 177 /* 178 * Refill the input buffer and return the next input character: 179 * 180 * 1) If a string was pushed back on the input, pop it; 181 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading 182 * from a string so we can't refill the buffer, return EOF. 183 * 3) If there is more in this buffer, use it else call read to fill it. 184 * 4) Process input up to the next newline, deleting nul characters. 185 */ 186 187 int 188 preadbuffer(void) 189 { 190 char *p, *q, *r, *end; 191 char savec; 192 193 while (parsefile->strpush) { 194 /* 195 * Add a space to the end of an alias to ensure that the 196 * alias remains in use while parsing its last word. 197 * This avoids alias recursions. 198 */ 199 if (parsenleft == -1 && parsefile->strpush->ap != NULL) 200 return ' '; 201 popstring(); 202 if (--parsenleft >= 0) 203 return (*parsenextc++); 204 } 205 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 206 return PEOF; 207 208 again: 209 if (parselleft <= 0) { 210 if ((parselleft = preadfd()) == -1) { 211 parselleft = parsenleft = EOF_NLEFT; 212 return PEOF; 213 } 214 } 215 216 p = parsefile->buf + (parsenextc - parsefile->buf); 217 end = p + parselleft; 218 *end = '\0'; 219 q = strchrnul(p, '\n'); 220 if (q != end && *q == '\0') { 221 /* delete nul characters */ 222 for (r = q; q != end; q++) { 223 if (*q != '\0') 224 *r++ = *q; 225 } 226 parselleft -= end - r; 227 if (parselleft == 0) 228 goto again; 229 end = p + parselleft; 230 *end = '\0'; 231 q = strchrnul(p, '\n'); 232 } 233 if (q == end) { 234 parsenleft = parselleft; 235 parselleft = 0; 236 } else /* *q == '\n' */ { 237 q++; 238 parsenleft = q - parsenextc; 239 parselleft -= parsenleft; 240 } 241 parsenleft--; 242 243 savec = *q; 244 *q = '\0'; 245 246 #ifndef NO_HISTORY 247 if (parsefile->fd == 0 && hist && 248 parsenextc[strspn(parsenextc, " \t\n")] != '\0') { 249 HistEvent he; 250 INTOFF; 251 history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD, 252 parsenextc); 253 INTON; 254 } 255 #endif 256 257 if (vflag) { 258 out2str(parsenextc); 259 flushout(out2); 260 } 261 262 *q = savec; 263 264 return *parsenextc++; 265 } 266 267 /* 268 * Returns if we are certain we are at EOF. Does not cause any more input 269 * to be read from the outside world. 270 */ 271 272 int 273 preadateof(void) 274 { 275 if (parsenleft > 0) 276 return 0; 277 if (parsefile->strpush) 278 return 0; 279 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL) 280 return 1; 281 return 0; 282 } 283 284 /* 285 * Undo the last call to pgetc. Only one character may be pushed back. 286 * PEOF may be pushed back. 287 */ 288 289 void 290 pungetc(void) 291 { 292 parsenleft++; 293 parsenextc--; 294 } 295 296 /* 297 * Push a string back onto the input at this current parsefile level. 298 * We handle aliases this way. 299 */ 300 void 301 pushstring(const char *s, int len, struct alias *ap) 302 { 303 struct strpush *sp; 304 305 INTOFF; 306 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/ 307 if (parsefile->strpush) { 308 sp = ckmalloc(sizeof (struct strpush)); 309 sp->prev = parsefile->strpush; 310 parsefile->strpush = sp; 311 } else 312 sp = parsefile->strpush = &(parsefile->basestrpush); 313 sp->prevstring = parsenextc; 314 sp->prevnleft = parsenleft; 315 sp->prevlleft = parselleft; 316 sp->ap = ap; 317 if (ap) 318 ap->flag |= ALIASINUSE; 319 parsenextc = s; 320 parsenleft = len; 321 INTON; 322 } 323 324 static void 325 popstring(void) 326 { 327 struct strpush *sp = parsefile->strpush; 328 329 INTOFF; 330 if (sp->ap) { 331 if (parsenextc != sp->ap->val && 332 (parsenextc[-1] == ' ' || parsenextc[-1] == '\t')) 333 forcealias(); 334 sp->ap->flag &= ~ALIASINUSE; 335 } 336 parsenextc = sp->prevstring; 337 parsenleft = sp->prevnleft; 338 parselleft = sp->prevlleft; 339 /*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/ 340 parsefile->strpush = sp->prev; 341 if (sp != &(parsefile->basestrpush)) 342 ckfree(sp); 343 INTON; 344 } 345 346 /* 347 * Set the input to take input from a file. If push is set, push the 348 * old input onto the stack first. 349 * About verify: 350 * -1: Obey verifyflag 351 * 0: Do not verify 352 * 1: Do verify 353 */ 354 355 void 356 setinputfile(const char *fname, int push, int verify) 357 { 358 int e; 359 int fd; 360 int fd2; 361 int oflags = O_RDONLY | O_CLOEXEC; 362 363 if (verify == 1 || (verify == -1 && verifyflag)) 364 oflags |= O_VERIFY; 365 366 INTOFF; 367 if ((fd = open(fname, oflags)) < 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