bin/sh/input.c

   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  * 4. 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 MKINIT
  68 struct strpush {
  69         struct strpush *prev;   /* preceding string on stack */
  70         char *prevstring;
  71         int prevnleft;
  72         int prevlleft;
  73         struct alias *ap;       /* if push was associated with an alias */
  74 };
  75
  76 /*
  77  * The parsefile structure pointed to by the global variable parsefile
  78  * contains information about the current file being read.
  79  */
  80
  81 MKINIT
  82 struct parsefile {
  83         struct parsefile *prev; /* preceding file on stack */
  84         int linno;              /* current line */
  85         int fd;                 /* file descriptor (or -1 if string) */
  86         int nleft;              /* number of chars left in this line */
  87         int lleft;              /* number of lines left in this buffer */
  88         char *nextc;            /* next char in buffer */
  89         char *buf;              /* input buffer */
  90         struct strpush *strpush; /* for pushing strings at this level */
  91         struct strpush basestrpush; /* so pushing one is fast */
  92 };
  93
  94
  95 int plinno = 1;                 /* input line number */
  96 MKINIT int parsenleft;          /* copy of parsefile->nleft */
  97 MKINIT int parselleft;          /* copy of parsefile->lleft */
  98 char *parsenextc;               /* copy of parsefile->nextc */
  99 MKINIT struct parsefile basepf; /* top level input file */
 100 char basebuf[BUFSIZ];           /* buffer for top level input file */
 101 STATIC struct parsefile *parsefile = &basepf;   /* current input file */
 102 int init_editline = 0;          /* editline library initialized? */
 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
 110 #ifdef mkinit
 111 INCLUDE "input.h"
 112 INCLUDE "error.h"
 113
 114 INIT {
 115         extern char basebuf[];
 116
 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         parsenextc = parsefile->buf;
 177
 178 #ifndef NO_HISTORY
 179         if (el != NULL && gotwinch) {
 180                 gotwinch = 0;
 181                 el_resize(el);
 182         }
 183 #endif
 184 retry:
 185 #ifndef NO_HISTORY
 186         if (parsefile->fd == 0 && el) {
 187                 static const char *rl_cp;
 188                 static int el_len;
 189
 190                 if (rl_cp == NULL)
 191                         rl_cp = el_gets(el, &el_len);
 192                 if (rl_cp == NULL)
 193                         nr = 0;
 194                 else {
 195                         nr = el_len;
 196                         if (nr > BUFSIZ - 1)
 197                                 nr = BUFSIZ - 1;
 198                         memcpy(parsenextc, rl_cp, nr);
 199                         if (nr != el_len) {
 200                                 el_len -= nr;
 201                                 rl_cp += nr;
 202                         } else
 203                                 rl_cp = NULL;
 204                 }
 205         } else
 206 #endif
 207                 nr = read(parsefile->fd, parsenextc, BUFSIZ - 1);
 208
 209         if (nr <= 0) {
 210                 if (nr < 0) {
 211                         if (errno == EINTR)
 212                                 goto retry;
 213                         if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
 214                                 int flags = fcntl(0, F_GETFL, 0);
 215                                 if (flags >= 0 && flags & O_NONBLOCK) {
 216                                         flags &=~ O_NONBLOCK;
 217                                         if (fcntl(0, F_SETFL, flags) >= 0) {
 218                                                 out2str("sh: turning off NDELAY mode\n");
 219                                                 goto retry;
 220                                         }
 221                                 }
 222                         }
 223                 }
 224                 nr = -1;
 225         }
 226         return nr;
 227 }
 228
 229 /*
 230  * Refill the input buffer and return the next input character:
 231  *
 232  * 1) If a string was pushed back on the input, pop it;
 233  * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
 234  *    from a string so we can't refill the buffer, return EOF.
 235  * 3) If there is more in this buffer, use it else call read to fill it.
 236  * 4) Process input up to the next newline, deleting nul characters.
 237  */
 238
 239 int
 240 preadbuffer(void)
 241 {
 242         char *p, *q;
 243         int more;
 244         int something;
 245         char savec;
 246
 247         if (parsefile->strpush) {
 248                 popstring();
 249                 if (--parsenleft >= 0)
 250                         return (*parsenextc++);
 251         }
 252         if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
 253                 return PEOF;
 254         flushout(&output);
 255         flushout(&errout);
 256
 257 again:
 258         if (parselleft <= 0) {
 259                 if ((parselleft = preadfd()) == -1) {
 260                         parselleft = parsenleft = EOF_NLEFT;
 261                         return PEOF;
 262                 }
 263         }
 264
 265         q = p = parsenextc;
 266
 267         /* delete nul characters */
 268         something = 0;
 269         for (more = 1; more;) {
 270                 switch (*p) {
 271                 case '\0':
 272                         p++;    /* Skip nul */
 273                         goto check;
 274
 275                 case '\t':
 276                 case ' ':
 277                         break;
 278
 279                 case '\n':
 280                         parsenleft = q - parsenextc;
 281                         more = 0; /* Stop processing here */
 282                         break;
 283
 284                 default:
 285                         something = 1;
 286                         break;
 287                 }
 288
 289                 *q++ = *p++;
 290 check:
 291                 if (--parselleft <= 0) {
 292                         parsenleft = q - parsenextc - 1;
 293                         if (parsenleft < 0)
 294                                 goto again;
 295                         *q = '\0';
 296                         more = 0;
 297                 }
 298         }
 299
 300         savec = *q;
 301         *q = '\0';
 302
 303 #ifndef NO_HISTORY
 304         if (parsefile->fd == 0 && hist && something) {
 305                 HistEvent he;
 306                 INTOFF;
 307                 history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
 308                     parsenextc);
 309                 INTON;
 310         }
 311 #endif
 312
 313         if (vflag) {
 314                 out2str(parsenextc);
 315                 flushout(out2);
 316         }
 317
 318         *q = savec;
 319
 320         return *parsenextc++;
 321 }
 322
 323 /*
 324  * Undo the last call to pgetc.  Only one character may be pushed back.
 325  * PEOF may be pushed back.
 326  */
 327
 328 void
 329 pungetc(void)
 330 {
 331         parsenleft++;
 332         parsenextc--;
 333 }
 334
 335 /*
 336  * Push a string back onto the input at this current parsefile level.
 337  * We handle aliases this way.
 338  */
 339 void
 340 pushstring(char *s, int len, void *ap)
 341 {
 342         struct strpush *sp;
 343
 344         INTOFF;
 345 /*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
 346         if (parsefile->strpush) {
 347                 sp = ckmalloc(sizeof (struct strpush));
 348                 sp->prev = parsefile->strpush;
 349                 parsefile->strpush = sp;
 350         } else
 351                 sp = parsefile->strpush = &(parsefile->basestrpush);
 352         sp->prevstring = parsenextc;
 353         sp->prevnleft = parsenleft;
 354         sp->prevlleft = parselleft;
 355         sp->ap = (struct alias *)ap;
 356         if (ap)
 357                 ((struct alias *)ap)->flag |= ALIASINUSE;
 358         parsenextc = s;
 359         parsenleft = len;
 360         INTON;
 361 }
 362
 363 void
 364 popstring(void)
 365 {
 366         struct strpush *sp = parsefile->strpush;
 367
 368         INTOFF;
 369         parsenextc = sp->prevstring;
 370         parsenleft = sp->prevnleft;
 371         parselleft = sp->prevlleft;
 372 /*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
 373         if (sp->ap)
 374                 sp->ap->flag &= ~ALIASINUSE;
 375         parsefile->strpush = sp->prev;
 376         if (sp != &(parsefile->basestrpush))
 377                 ckfree(sp);
 378         INTON;
 379 }
 380
 381 /*
 382  * Set the input to take input from a file.  If push is set, push the
 383  * old input onto the stack first.
 384  */
 385
 386 void
 387 setinputfile(char *fname, int push)
 388 {
 389         int fd;
 390         int fd2;
 391
 392         INTOFF;
 393         if ((fd = open(fname, O_RDONLY)) < 0)
 394                 error("Can't open %s: %s", fname, strerror(errno));
 395         if (fd < 10) {
 396                 fd2 = fcntl(fd, F_DUPFD, 10);
 397                 close(fd);
 398                 if (fd2 < 0)
 399                         error("Out of file descriptors");
 400                 fd = fd2;
 401         }
 402         setinputfd(fd, push);
 403         INTON;
 404 }
 405
 406
 407 /*
 408  * Like setinputfile, but takes an open file descriptor.  Call this with
 409  * interrupts off.
 410  */
 411
 412 void
 413 setinputfd(int fd, int push)
 414 {
 415         (void)fcntl(fd, F_SETFD, FD_CLOEXEC);
 416         if (push) {
 417                 pushfile();
 418                 parsefile->buf = ckmalloc(BUFSIZ);
 419         }
 420         if (parsefile->fd > 0)
 421                 close(parsefile->fd);
 422         parsefile->fd = fd;
 423         if (parsefile->buf == NULL)
 424                 parsefile->buf = ckmalloc(BUFSIZ);
 425         parselleft = parsenleft = 0;
 426         plinno = 1;
 427 }
 428
 429
 430 /*
 431  * Like setinputfile, but takes input from a string.
 432  */
 433
 434 void
 435 setinputstring(char *string, int push)
 436 {
 437         INTOFF;
 438         if (push)
 439                 pushfile();
 440         parsenextc = string;
 441         parselleft = parsenleft = strlen(string);
 442         parsefile->buf = NULL;
 443         plinno = 1;
 444         INTON;
 445 }
 446
 447
 448
 449 /*
 450  * To handle the "." command, a stack of input files is used.  Pushfile
 451  * adds a new entry to the stack and popfile restores the previous level.
 452  */
 453
 454 STATIC void
 455 pushfile(void)
 456 {
 457         struct parsefile *pf;
 458
 459         parsefile->nleft = parsenleft;
 460         parsefile->lleft = parselleft;
 461         parsefile->nextc = parsenextc;
 462         parsefile->linno = plinno;
 463         pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
 464         pf->prev = parsefile;
 465         pf->fd = -1;
 466         pf->strpush = NULL;
 467         pf->basestrpush.prev = NULL;
 468         parsefile = pf;
 469 }
 470
 471
 472 void
 473 popfile(void)
 474 {
 475         struct parsefile *pf = parsefile;
 476
 477         INTOFF;
 478         if (pf->fd >= 0)
 479                 close(pf->fd);
 480         if (pf->buf)
 481                 ckfree(pf->buf);
 482         while (pf->strpush)
 483                 popstring();
 484         parsefile = pf->prev;
 485         ckfree(pf);
 486         parsenleft = parsefile->nleft;
 487         parselleft = parsefile->lleft;
 488         parsenextc = parsefile->nextc;
 489         plinno = parsefile->linno;
 490         INTON;
 491 }
 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 }