bin/sh/input.c

   1 /*      $NetBSD: input.c,v 1.46 2013/10/30 08:38:40 mrg Exp $   */
   2
   3 /*-
   4  * Copyright (c) 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Kenneth Almquist.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #ifndef lint
  37 #if 0
  38 static char sccsid[] = "@(#)input.c     8.3 (Berkeley) 6/9/95";
  39 #else
  40 __RCSID("$NetBSD: input.c,v 1.46 2013/10/30 08:38:40 mrg Exp $");
  41 #endif
  42 #endif /* not lint */
  43
  44 #include <stdio.h>      /* defines BUFSIZ */
  45 #include <fcntl.h>
  46 #include <errno.h>
  47 #include <unistd.h>
  48 #include <limits.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51
  52 /*
  53  * This file implements the input routines used by the parser.
  54  */
  55
  56 #include "shell.h"
  57 #include "redir.h"
  58 #include "syntax.h"
  59 #include "input.h"
  60 #include "output.h"
  61 #include "options.h"
  62 #include "memalloc.h"
  63 #include "error.h"
  64 #include "alias.h"
  65 #include "parser.h"
  66 #include "myhistedit.h"
  67
  68 #define EOF_NLEFT -99           /* value of parsenleft when EOF pushed back */
  69
  70 MKINIT
  71 struct strpush {
  72         struct strpush *prev;   /* preceding string on stack */
  73         char *prevstring;
  74         int prevnleft;
  75         int prevlleft;
  76         struct alias *ap;       /* if push was associated with an alias */
  77 };
  78
  79 /*
  80  * The parsefile structure pointed to by the global variable parsefile
  81  * contains information about the current file being read.
  82  */
  83
  84 MKINIT
  85 struct parsefile {
  86         struct parsefile *prev; /* preceding file on stack */
  87         int linno;              /* current line */
  88         int fd;                 /* file descriptor (or -1 if string) */
  89         int nleft;              /* number of chars left in this line */
  90         int lleft;              /* number of chars left in this buffer */
  91         char *nextc;            /* next char in buffer */
  92         char *buf;              /* input buffer */
  93         struct strpush *strpush; /* for pushing strings at this level */
  94         struct strpush basestrpush; /* so pushing one is fast */
  95 };
  96
  97
  98 int plinno = 1;                 /* input line number */
  99 int parsenleft;                 /* copy of parsefile->nleft */
 100 MKINIT int parselleft;          /* copy of parsefile->lleft */
 101 char *parsenextc;               /* copy of parsefile->nextc */
 102 MKINIT struct parsefile basepf; /* top level input file */
 103 MKINIT char basebuf[BUFSIZ];    /* buffer for top level input file */
 104 struct parsefile *parsefile = &basepf;  /* current input file */
 105 int init_editline = 0;          /* editline library initialized? */
 106 int whichprompt;                /* 1 == PS1, 2 == PS2 */
 107
 108 STATIC void pushfile(void);
 109 static int preadfd(void);
 110
 111 #ifdef mkinit
 112 INCLUDE <stdio.h>
 113 INCLUDE "input.h"
 114 INCLUDE "error.h"
 115
 116 INIT {
 117         basepf.nextc = basepf.buf = basebuf;
 118 }
 119
 120 RESET {
 121         if (exception != EXSHELLPROC)
 122                 parselleft = parsenleft = 0;    /* clear input buffer */
 123         popallfiles();
 124 }
 125
 126 SHELLPROC {
 127         popallfiles();
 128 }
 129 #endif
 130
 131
 132 /*
 133  * Read a line from the script.
 134  */
 135
 136 char *
 137 pfgets(char *line, int len)
 138 {
 139         char *p = line;
 140         int nleft = len;
 141         int c;
 142
 143         while (--nleft > 0) {
 144                 c = pgetc_macro();
 145                 if (c == PEOF) {
 146                         if (p == line)
 147                                 return NULL;
 148                         break;
 149                 }
 150                 *p++ = c;
 151                 if (c == '\n')
 152                         break;
 153         }
 154         *p = '\0';
 155         return line;
 156 }
 157
 158
 159
 160 /*
 161  * Read a character from the script, returning PEOF on end of file.
 162  * Nul characters in the input are silently discarded.
 163  */
 164
 165 int
 166 pgetc(void)
 167 {
 168         return pgetc_macro();
 169 }
 170
 171
 172 static int
 173 preadfd(void)
 174 {
 175         int nr;
 176         char *buf =  parsefile->buf;
 177         parsenextc = buf;
 178
 179 retry:
 180 #ifndef SMALL
 181         if (parsefile->fd == 0 && el) {
 182                 static const char *rl_cp;
 183                 static int el_len;
 184
 185                 if (rl_cp == NULL)
 186                         rl_cp = el_gets(el, &el_len);
 187                 if (rl_cp == NULL)
 188                         nr = el_len == 0 ? 0 : -1;
 189                 else {
 190                         nr = el_len;
 191                         if (nr > BUFSIZ - 8)
 192                                 nr = BUFSIZ - 8;
 193                         memcpy(buf, rl_cp, nr);
 194                         if (nr != el_len) {
 195                                 el_len -= nr;
 196                                 rl_cp += nr;
 197                         } else
 198                                 rl_cp = 0;
 199                 }
 200
 201         } else
 202 #endif
 203                 nr = read(parsefile->fd, buf, BUFSIZ - 8);
 204
 205
 206         if (nr <= 0) {
 207                 if (nr < 0) {
 208                         if (errno == EINTR)
 209                                 goto retry;
 210                         if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
 211                                 int flags = fcntl(0, F_GETFL, 0);
 212                                 if (flags >= 0 && flags & O_NONBLOCK) {
 213                                         flags &=~ O_NONBLOCK;
 214                                         if (fcntl(0, F_SETFL, flags) >= 0) {
 215                                                 out2str("sh: turning off NDELAY mode\n");
 216                                                 goto retry;
 217                                         }
 218                                 }
 219                         }
 220                 }
 221                 nr = -1;
 222         }
 223         return nr;
 224 }
 225
 226 /*
 227  * Refill the input buffer and return the next input character:
 228  *
 229  * 1) If a string was pushed back on the input, pop it;
 230  * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
 231  *    from a string so we can't refill the buffer, return EOF.
 232  * 3) If the is more stuff in this buffer, use it else call read to fill it.
 233  * 4) Process input up to the next newline, deleting nul characters.
 234  */
 235
 236 int
 237 preadbuffer(void)
 238 {
 239         char *p, *q;
 240         int more;
 241 #ifndef SMALL
 242         int something;
 243 #endif
 244         char savec;
 245
 246         if (parsefile->strpush) {
 247                 popstring();
 248                 if (--parsenleft >= 0)
 249                         return (*parsenextc++);
 250         }
 251         if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
 252                 return PEOF;
 253         flushout(&output);
 254         flushout(&errout);
 255
 256 again:
 257         if (parselleft <= 0) {
 258                 if ((parselleft = preadfd()) == -1) {
 259                         parselleft = parsenleft = EOF_NLEFT;
 260                         return PEOF;
 261                 }
 262         }
 263
 264         q = p = parsenextc;
 265
 266         /* delete nul characters */
 267 #ifndef SMALL
 268         something = 0;
 269 #endif
 270         for (more = 1; more;) {
 271                 switch (*p) {
 272                 case '\0':
 273                         p++;    /* Skip nul */
 274                         goto check;
 275
 276                 case '\t':
 277                 case ' ':
 278                         break;
 279
 280                 case '\n':
 281                         parsenleft = q - parsenextc;
 282                         more = 0; /* Stop processing here */
 283                         break;
 284
 285                 default:
 286 #ifndef SMALL
 287                         something = 1;
 288 #endif
 289                         break;
 290                 }
 291
 292                 *q++ = *p++;
 293 check:
 294                 if (--parselleft <= 0) {
 295                         parsenleft = q - parsenextc - 1;
 296                         if (parsenleft < 0)
 297                                 goto again;
 298                         *q = '\0';
 299                         more = 0;
 300                 }
 301         }
 302
 303         savec = *q;
 304         *q = '\0';
 305
 306 #ifndef SMALL
 307         if (parsefile->fd == 0 && hist && something) {
 308                 HistEvent he;
 309                 INTOFF;
 310                 history(hist, &he, whichprompt == 1? H_ENTER : H_APPEND,
 311                     parsenextc);
 312                 INTON;
 313         }
 314 #endif
 315
 316         if (vflag) {
 317                 out2str(parsenextc);
 318                 flushout(out2);
 319         }
 320
 321         *q = savec;
 322
 323         return *parsenextc++;
 324 }
 325
 326 /*
 327  * Undo the last call to pgetc.  Only one character may be pushed back.
 328  * PEOF may be pushed back.
 329  */
 330
 331 void
 332 pungetc(void)
 333 {
 334         parsenleft++;
 335         parsenextc--;
 336 }
 337
 338 /*
 339  * Push a string back onto the input at this current parsefile level.
 340  * We handle aliases this way.
 341  */
 342 void
 343 pushstring(char *s, int len, void *ap)
 344 {
 345         struct strpush *sp;
 346
 347         INTOFF;
 348 /*debugprintf("*** calling pushstring: %s, %d\n", s, len);*/
 349         if (parsefile->strpush) {
 350                 sp = ckmalloc(sizeof (struct strpush));
 351                 sp->prev = parsefile->strpush;
 352                 parsefile->strpush = sp;
 353         } else
 354                 sp = parsefile->strpush = &(parsefile->basestrpush);
 355         sp->prevstring = parsenextc;
 356         sp->prevnleft = parsenleft;
 357         sp->prevlleft = parselleft;
 358         sp->ap = (struct alias *)ap;
 359         if (ap)
 360                 ((struct alias *)ap)->flag |= ALIASINUSE;
 361         parsenextc = s;
 362         parsenleft = len;
 363         INTON;
 364 }
 365
 366 void
 367 popstring(void)
 368 {
 369         struct strpush *sp = parsefile->strpush;
 370
 371         INTOFF;
 372         parsenextc = sp->prevstring;
 373         parsenleft = sp->prevnleft;
 374         parselleft = sp->prevlleft;
 375 /*debugprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
 376         if (sp->ap)
 377                 sp->ap->flag &= ~ALIASINUSE;
 378         parsefile->strpush = sp->prev;
 379         if (sp != &(parsefile->basestrpush))
 380                 ckfree(sp);
 381         INTON;
 382 }
 383
 384 /*
 385  * Set the input to take input from a file.  If push is set, push the
 386  * old input onto the stack first.
 387  */
 388
 389 void
 390 setinputfile(const char *fname, int push)
 391 {
 392         unsigned char magic[4];
 393         int fd;
 394         int fd2;
 395
 396         INTOFF;
 397         if ((fd = open(fname, O_RDONLY)) < 0)
 398                 error("Can't open %s", fname);
 399
 400         /* Since the message "Syntax error: "(" unexpected" is not very
 401          * helpful, we check if the file starts with the ELF magic to
 402          * avoid that message. The first lseek tries to make sure that
 403          * we can later rewind the file.
 404          */
 405         if (lseek(fd, 0, SEEK_SET) == 0) {
 406                 if (read(fd, magic, 4) == 4) {
 407                         if (memcmp(magic, "\177ELF", 4) == 0)
 408                                 error("Cannot execute ELF binary %s", fname);
 409                 }
 410                 if (lseek(fd, 0, SEEK_SET) != 0)
 411                         error("Cannot rewind the file %s", fname);
 412         }
 413
 414         if (fd < 10) {
 415                 fd2 = copyfd(fd, 10, 0);
 416                 close(fd);
 417                 if (fd2 < 0)
 418                         error("Out of file descriptors");
 419                 fd = fd2;
 420         }
 421         setinputfd(fd, push);
 422         INTON;
 423 }
 424
 425
 426 /*
 427  * Like setinputfile, but takes an open file descriptor.  Call this with
 428  * interrupts off.
 429  */
 430
 431 void
 432 setinputfd(int fd, int push)
 433 {
 434         (void) fcntl(fd, F_SETFD, FD_CLOEXEC);
 435         if (push) {
 436                 pushfile();
 437                 parsefile->buf = ckmalloc(BUFSIZ);
 438         }
 439         if (parsefile->fd > 0)
 440                 close(parsefile->fd);
 441         parsefile->fd = fd;
 442         if (parsefile->buf == NULL)
 443                 parsefile->buf = ckmalloc(BUFSIZ);
 444         parselleft = parsenleft = 0;
 445         plinno = 1;
 446 }
 447
 448
 449 /*
 450  * Like setinputfile, but takes input from a string.
 451  */
 452
 453 void
 454 setinputstring(char *string, int push)
 455 {
 456         INTOFF;
 457         if (push)
 458                 pushfile();
 459         parsenextc = string;
 460         parselleft = parsenleft = strlen(string);
 461         parsefile->buf = NULL;
 462         plinno = 1;
 463         INTON;
 464 }
 465
 466
 467
 468 /*
 469  * To handle the "." command, a stack of input files is used.  Pushfile
 470  * adds a new entry to the stack and popfile restores the previous level.
 471  */
 472
 473 STATIC void
 474 pushfile(void)
 475 {
 476         struct parsefile *pf;
 477
 478         parsefile->nleft = parsenleft;
 479         parsefile->lleft = parselleft;
 480         parsefile->nextc = parsenextc;
 481         parsefile->linno = plinno;
 482         pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
 483         pf->prev = parsefile;
 484         pf->fd = -1;
 485         pf->strpush = NULL;
 486         pf->basestrpush.prev = NULL;
 487         parsefile = pf;
 488 }
 489
 490
 491 void
 492 popfile(void)
 493 {
 494         struct parsefile *pf = parsefile;
 495
 496         INTOFF;
 497         if (pf->fd >= 0)
 498                 close(pf->fd);
 499         if (pf->buf)
 500                 ckfree(pf->buf);
 501         while (pf->strpush)
 502                 popstring();
 503         parsefile = pf->prev;
 504         ckfree(pf);
 505         parsenleft = parsefile->nleft;
 506         parselleft = parsefile->lleft;
 507         parsenextc = parsefile->nextc;
 508         plinno = parsefile->linno;
 509         INTON;
 510 }
 511
 512
 513 /*
 514  * Return to top level.
 515  */
 516
 517 void
 518 popallfiles(void)
 519 {
 520         while (parsefile != &basepf)
 521                 popfile();
 522 }
 523
 524
 525
 526 /*
 527  * Close the file(s) that the shell is reading commands from.  Called
 528  * after a fork is done.
 529  *
 530  * Takes one arg, vfork, which tells it to not modify its global vars
 531  * as it is still running in the parent.
 532  *
 533  * This code is (probably) unnecessary as the 'close on exec' flag is
 534  * set and should be enough.  In the vfork case it is definitely wrong
 535  * to close the fds as another fork() may be done later to feed data
 536  * from a 'here' document into a pipe and we don't want to close the
 537  * pipe!
 538  */
 539
 540 void
 541 closescript(int vforked)
 542 {
 543         if (vforked)
 544                 return;
 545         popallfiles();
 546         if (parsefile->fd > 0) {
 547                 close(parsefile->fd);
 548                 parsefile->fd = 0;
 549         }
 550 }