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  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)input.c  8.3 (Berkeley) 6/9/95
  37  * $FreeBSD: src/bin/sh/input.c,v 1.23 2006/04/29 10:29:10 stefanf Exp $
  38  * $DragonFly: src/bin/sh/input.c,v 1.8 2007/01/13 20:10:26 pavalos Exp $
  39  */
  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 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 MKINIT 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 <stdio.h>
 112 INCLUDE "input.h"
 113 INCLUDE "error.h"
 114
 115 INIT {
 116         basepf.nextc = basepf.buf = basebuf;
 117 }
 118
 119 RESET {
 120         if (exception != EXSHELLPROC)
 121                 parselleft = parsenleft = 0;    /* clear input buffer */
 122         popallfiles();
 123 }
 124
 125 SHELLPROC {
 126         popallfiles();
 127 }
 128 #endif
 129
 130
 131 /*
 132  * Read a line from the script.
 133  */
 134
 135 char *
 136 pfgets(char *line, int len)
 137 {
 138         char *p = line;
 139         int nleft = len;
 140         int c;
 141
 142         while (--nleft > 0) {
 143                 c = pgetc_macro();
 144                 if (c == PEOF) {
 145                         if (p == line)
 146                                 return NULL;
 147                         break;
 148                 }
 149                 *p++ = c;
 150                 if (c == '\n')
 151                         break;
 152         }
 153         *p = '\0';
 154         return line;
 155 }
 156
 157
 158
 159 /*
 160  * Read a character from the script, returning PEOF on end of file.
 161  * Nul characters in the input are silently discarded.
 162  */
 163
 164 int
 165 pgetc(void)
 166 {
 167         return pgetc_macro();
 168 }
 169
 170
 171 static int
 172 preadfd(void)
 173 {
 174         int nr;
 175         parsenextc = parsefile->buf;
 176
 177 #ifndef NO_HISTORY
 178         if (el != NULL && gotwinch) {
 179                 gotwinch = 0;
 180                 el_resize(el);
 181         }
 182 #endif
 183 retry:
 184 #ifndef NO_HISTORY
 185         if (parsefile->fd == 0 && el) {
 186                 static const char *rl_cp;
 187                 static int el_len;
 188
 189                 if (rl_cp == NULL)
 190                         rl_cp = el_gets(el, &el_len);
 191                 if (rl_cp == NULL)
 192                         nr = 0;
 193                 else {
 194                         nr = el_len;
 195                         if (nr > BUFSIZ - 1)
 196                                 nr = BUFSIZ - 1;
 197                         memcpy(parsenextc, rl_cp, nr);
 198                         if (nr != el_len) {
 199                                 el_len -= nr;
 200                                 rl_cp += nr;
 201                         } else
 202                                 rl_cp = NULL;
 203                 }
 204         } else
 205 #endif
 206                 nr = read(parsefile->fd, parsenextc, BUFSIZ - 1);
 207
 208         if (nr <= 0) {
 209                 if (nr < 0) {
 210                         if (errno == EINTR)
 211                                 goto retry;
 212                         if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
 213                                 int flags = fcntl(0, F_GETFL, 0);
 214                                 if (flags >= 0 && flags & O_NONBLOCK) {
 215                                         flags &=~ O_NONBLOCK;
 216                                         if (fcntl(0, F_SETFL, flags) >= 0) {
 217                                                 out2str("sh: turning off NDELAY mode\n");
 218                                                 goto retry;
 219                                         }
 220                                 }
 221                         }
 222                 }
 223                 nr = -1;
 224         }
 225         return nr;
 226 }
 227
 228 /*
 229  * Refill the input buffer and return the next input character:
 230  *
 231  * 1) If a string was pushed back on the input, pop it;
 232  * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
 233  *    from a string so we can't refill the buffer, return EOF.
 234  * 3) If there is more in this buffer, use it else call read to fill it.
 235  * 4) Process input up to the next newline, deleting nul characters.
 236  */
 237
 238 int
 239 preadbuffer(void)
 240 {
 241         char *p, *q;
 242         int more;
 243         int something;
 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         something = 0;
 268         for (more = 1; more;) {
 269                 switch (*p) {
 270                 case '\0':
 271                         p++;    /* Skip nul */
 272                         goto check;
 273
 274                 case '\t':
 275                 case ' ':
 276                         break;
 277
 278                 case '\n':
 279                         parsenleft = q - parsenextc;
 280                         more = 0; /* Stop processing here */
 281                         break;
 282
 283                 default:
 284                         something = 1;
 285                         break;
 286                 }
 287
 288                 *q++ = *p++;
 289 check:
 290                 if (--parselleft <= 0) {
 291                         parsenleft = q - parsenextc - 1;
 292                         if (parsenleft < 0)
 293                                 goto again;
 294                         *q = '\0';
 295                         more = 0;
 296                 }
 297         }
 298
 299         savec = *q;
 300         *q = '\0';
 301
 302 #ifndef NO_HISTORY
 303         if (parsefile->fd == 0 && hist && something) {
 304                 HistEvent he;
 305                 INTOFF;
 306                 history(hist, &he, whichprompt == 1 ? H_ENTER : H_APPEND, parsenextc);
 307                 INTON;
 308         }
 309 #endif
 310
 311         if (vflag) {
 312                 out2str(parsenextc);
 313                 flushout(out2);
 314         }
 315
 316         *q = savec;
 317
 318         return *parsenextc++;
 319 }
 320
 321 /*
 322  * Undo the last call to pgetc.  Only one character may be pushed back.
 323  * PEOF may be pushed back.
 324  */
 325
 326 void
 327 pungetc(void)
 328 {
 329         parsenleft++;
 330         parsenextc--;
 331 }
 332
 333 /*
 334  * Push a string back onto the input at this current parsefile level.
 335  * We handle aliases this way.
 336  */
 337 void
 338 pushstring(char *s, int len, void *ap)
 339 {
 340         struct strpush *sp;
 341
 342         INTOFF;
 343 /*dprintf("*** calling pushstring: %s, %d\n", s, len);*/
 344         if (parsefile->strpush) {
 345                 sp = ckmalloc(sizeof (struct strpush));
 346                 sp->prev = parsefile->strpush;
 347                 parsefile->strpush = sp;
 348         } else
 349                 sp = parsefile->strpush = &(parsefile->basestrpush);
 350         sp->prevstring = parsenextc;
 351         sp->prevnleft = parsenleft;
 352         sp->prevlleft = parselleft;
 353         sp->ap = (struct alias *)ap;
 354         if (ap)
 355                 ((struct alias *)ap)->flag |= ALIASINUSE;
 356         parsenextc = s;
 357         parsenleft = len;
 358         INTON;
 359 }
 360
 361 void
 362 popstring(void)
 363 {
 364         struct strpush *sp = parsefile->strpush;
 365
 366         INTOFF;
 367         parsenextc = sp->prevstring;
 368         parsenleft = sp->prevnleft;
 369         parselleft = sp->prevlleft;
 370 /*dprintf("*** calling popstring: restoring to '%s'\n", parsenextc);*/
 371         if (sp->ap)
 372                 sp->ap->flag &= ~ALIASINUSE;
 373         parsefile->strpush = sp->prev;
 374         if (sp != &(parsefile->basestrpush))
 375                 ckfree(sp);
 376         INTON;
 377 }
 378
 379 /*
 380  * Set the input to take input from a file.  If push is set, push the
 381  * old input onto the stack first.
 382  */
 383
 384 void
 385 setinputfile(const char *fname, int push)
 386 {
 387         int fd;
 388         int fd2;
 389
 390         INTOFF;
 391         if ((fd = open(fname, O_RDONLY)) < 0)
 392                 error("Can't open %s: %s", fname, strerror(errno));
 393         if (fd < 10) {
 394                 fd2 = fcntl(fd, F_DUPFD, 10);
 395                 close(fd);
 396                 if (fd2 < 0)
 397                         error("Out of file descriptors");
 398                 fd = fd2;
 399         }
 400         setinputfd(fd, push);
 401         INTON;
 402 }
 403
 404
 405 /*
 406  * Like setinputfile, but takes an open file descriptor.  Call this with
 407  * interrupts off.
 408  */
 409
 410 void
 411 setinputfd(int fd, int push)
 412 {
 413         fcntl(fd, F_SETFD, FD_CLOEXEC);
 414         if (push) {
 415                 pushfile();
 416                 parsefile->buf = ckmalloc(BUFSIZ);
 417         }
 418         if (parsefile->fd > 0)
 419                 close(parsefile->fd);
 420         parsefile->fd = fd;
 421         if (parsefile->buf == NULL)
 422                 parsefile->buf = ckmalloc(BUFSIZ);
 423         parselleft = parsenleft = 0;
 424         plinno = 1;
 425 }
 426
 427
 428 /*
 429  * Like setinputfile, but takes input from a string.
 430  */
 431
 432 void
 433 setinputstring(char *string, int push)
 434 {
 435         INTOFF;
 436         if (push)
 437                 pushfile();
 438         parsenextc = string;
 439         parselleft = parsenleft = strlen(string);
 440         parsefile->buf = NULL;
 441         plinno = 1;
 442         INTON;
 443 }
 444
 445
 446
 447 /*
 448  * To handle the "." command, a stack of input files is used.  Pushfile
 449  * adds a new entry to the stack and popfile restores the previous level.
 450  */
 451
 452 STATIC void
 453 pushfile(void)
 454 {
 455         struct parsefile *pf;
 456
 457         parsefile->nleft = parsenleft;
 458         parsefile->lleft = parselleft;
 459         parsefile->nextc = parsenextc;
 460         parsefile->linno = plinno;
 461         pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
 462         pf->prev = parsefile;
 463         pf->fd = -1;
 464         pf->strpush = NULL;
 465         pf->basestrpush.prev = NULL;
 466         parsefile = pf;
 467 }
 468
 469
 470 void
 471 popfile(void)
 472 {
 473         struct parsefile *pf = parsefile;
 474
 475         INTOFF;
 476         if (pf->fd >= 0)
 477                 close(pf->fd);
 478         if (pf->buf)
 479                 ckfree(pf->buf);
 480         while (pf->strpush)
 481                 popstring();
 482         parsefile = pf->prev;
 483         ckfree(pf);
 484         parsenleft = parsefile->nleft;
 485         parselleft = parsefile->lleft;
 486         parsenextc = parsefile->nextc;
 487         plinno = parsefile->linno;
 488         INTON;
 489 }
 490
 491
 492 /*
 493  * Return to top level.
 494  */
 495
 496 void
 497 popallfiles(void)
 498 {
 499         while (parsefile != &basepf)
 500                 popfile();
 501 }
 502
 503
 504
 505 /*
 506  * Close the file(s) that the shell is reading commands from.  Called
 507  * after a fork is done.
 508  */
 509
 510 void
 511 closescript(void)
 512 {
 513         popallfiles();
 514         if (parsefile->fd > 0) {
 515                 close(parsefile->fd);
 516                 parsefile->fd = 0;
 517         }
 518 }