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