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: stable/10/bin/sh/input.c 262951 2014-03-09 17:04:31Z jmmv $");
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 struct strpush {
68 struct strpush *prev; /* preceding string on stack */
69 const char *prevstring;
70 int prevnleft;
71 int prevlleft;
72 struct alias *ap; /* if push was associated with an alias */
73 };
74
75 /*
76 * The parsefile structure pointed to by the global variable parsefile
77 * contains information about the current file being read.
78 */
79
80 struct parsefile {
81 struct parsefile *prev; /* preceding file on stack */
82 int linno; /* current line */
83 int fd; /* file descriptor (or -1 if string) */
84 int nleft; /* number of chars left in this line */
85 int lleft; /* number of lines left in this buffer */
86 const char *nextc; /* next char in buffer */
87 char *buf; /* input buffer */
88 struct strpush *strpush; /* for pushing strings at this level */
89 struct strpush basestrpush; /* so pushing one is fast */
90 };
91
92
93 int plinno = 1; /* input line number */
94 int parsenleft; /* copy of parsefile->nleft */
95 static int parselleft; /* copy of parsefile->lleft */
96 const char *parsenextc; /* copy of parsefile->nextc */
97 static char basebuf[BUFSIZ + 1];/* buffer for top level input file */
98 static struct parsefile basepf = { /* top level input file */
99 .nextc = basebuf,
100 .buf = basebuf
101 };
102 static struct parsefile *parsefile = &basepf; /* current input file */
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 static void popstring(void);
110
111 void
resetinput(void)112 resetinput(void)
113 {
114 popallfiles();
115 parselleft = parsenleft = 0; /* clear input buffer */
116 }
117
118
119 /*
120 * Read a line from the script.
121 */
122
123 char *
pfgets(char * line,int len)124 pfgets(char *line, int len)
125 {
126 char *p = line;
127 int nleft = len;
128 int c;
129
130 while (--nleft > 0) {
131 c = pgetc_macro();
132 if (c == PEOF) {
133 if (p == line)
134 return NULL;
135 break;
136 }
137 *p++ = c;
138 if (c == '\n')
139 break;
140 }
141 *p = '\0';
142 return line;
143 }
144
145
146
147 /*
148 * Read a character from the script, returning PEOF on end of file.
149 * Nul characters in the input are silently discarded.
150 */
151
152 int
pgetc(void)153 pgetc(void)
154 {
155 return pgetc_macro();
156 }
157
158
159 static int
preadfd(void)160 preadfd(void)
161 {
162 int nr;
163 parsenextc = parsefile->buf;
164
165 retry:
166 #ifndef NO_HISTORY
167 if (parsefile->fd == 0 && el) {
168 static const char *rl_cp;
169 static int el_len;
170
171 if (rl_cp == NULL) {
172 el_resize(el);
173 rl_cp = el_gets(el, &el_len);
174 }
175 if (rl_cp == NULL)
176 nr = el_len == 0 ? 0 : -1;
177 else {
178 nr = el_len;
179 if (nr > BUFSIZ)
180 nr = BUFSIZ;
181 memcpy(parsefile->buf, rl_cp, nr);
182 if (nr != el_len) {
183 el_len -= nr;
184 rl_cp += nr;
185 } else
186 rl_cp = NULL;
187 }
188 } else
189 #endif
190 nr = read(parsefile->fd, parsefile->buf, BUFSIZ);
191
192 if (nr <= 0) {
193 if (nr < 0) {
194 if (errno == EINTR)
195 goto retry;
196 if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
197 int flags = fcntl(0, F_GETFL, 0);
198 if (flags >= 0 && flags & O_NONBLOCK) {
199 flags &=~ O_NONBLOCK;
200 if (fcntl(0, F_SETFL, flags) >= 0) {
201 out2fmt_flush("sh: turning off NDELAY mode\n");
202 goto retry;
203 }
204 }
205 }
206 }
207 nr = -1;
208 }
209 return nr;
210 }
211
212 /*
213 * Refill the input buffer and return the next input character:
214 *
215 * 1) If a string was pushed back on the input, pop it;
216 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
217 * from a string so we can't refill the buffer, return EOF.
218 * 3) If there is more in this buffer, use it else call read to fill it.
219 * 4) Process input up to the next newline, deleting nul characters.
220 */
221
222 int
preadbuffer(void)223 preadbuffer(void)
224 {
225 char *p, *q;
226 int more;
227 char savec;
228
229 while (parsefile->strpush) {
230 /*
231 * Add a space to the end of an alias to ensure that the
232 * alias remains in use while parsing its last word.
233 * This avoids alias recursions.
234 */
235 if (parsenleft == -1 && parsefile->strpush->ap != NULL)
236 return ' ';
237 popstring();
238 if (--parsenleft >= 0)
239 return (*parsenextc++);
240 }
241 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
242 return PEOF;
243 flushout(&output);
244 flushout(&errout);
245
246 again:
247 if (parselleft <= 0) {
248 if ((parselleft = preadfd()) == -1) {
249 parselleft = parsenleft = EOF_NLEFT;
250 return PEOF;
251 }
252 }
253
254 q = p = parsefile->buf + (parsenextc - parsefile->buf);
255
256 /* delete nul characters */
257 for (more = 1; more;) {
258 switch (*p) {
259 case '\0':
260 p++; /* Skip nul */
261 goto check;
262
263 case '\n':
264 parsenleft = q - parsenextc;
265 more = 0; /* Stop processing here */
266 break;
267
268 default:
269 break;
270 }
271
272 *q++ = *p++;
273 check:
274 if (--parselleft <= 0) {
275 parsenleft = q - parsenextc - 1;
276 if (parsenleft < 0)
277 goto again;
278 *q = '\0';
279 more = 0;
280 }
281 }
282
283 savec = *q;
284 *q = '\0';
285
286 #ifndef NO_HISTORY
287 if (parsefile->fd == 0 && hist &&
288 parsenextc[strspn(parsenextc, " \t\n")] != '\0') {
289 HistEvent he;
290 INTOFF;
291 history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
292 parsenextc);
293 INTON;
294 }
295 #endif
296
297 if (vflag) {
298 out2str(parsenextc);
299 flushout(out2);
300 }
301
302 *q = savec;
303
304 return *parsenextc++;
305 }
306
307 /*
308 * Returns if we are certain we are at EOF. Does not cause any more input
309 * to be read from the outside world.
310 */
311
312 int
preadateof(void)313 preadateof(void)
314 {
315 if (parsenleft > 0)
316 return 0;
317 if (parsefile->strpush)
318 return 0;
319 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
320 return 1;
321 return 0;
322 }
323
324 /*
325 * Undo the last call to pgetc. Only one character may be pushed back.
326 * PEOF may be pushed back.
327 */
328
329 void
pungetc(void)330 pungetc(void)
331 {
332 parsenleft++;
333 parsenextc--;
334 }
335
336 /*
337 * Push a string back onto the input at this current parsefile level.
338 * We handle aliases this way.
339 */
340 void
pushstring(char * s,int len,struct alias * ap)341 pushstring(char *s, int len, struct alias *ap)
342 {
343 struct strpush *sp;
344
345 INTOFF;
346 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
347 if (parsefile->strpush) {
348 sp = ckmalloc(sizeof (struct strpush));
349 sp->prev = parsefile->strpush;
350 parsefile->strpush = sp;
351 } else
352 sp = parsefile->strpush = &(parsefile->basestrpush);
353 sp->prevstring = parsenextc;
354 sp->prevnleft = parsenleft;
355 sp->prevlleft = parselleft;
356 sp->ap = ap;
357 if (ap)
358 ap->flag |= ALIASINUSE;
359 parsenextc = s;
360 parsenleft = len;
361 INTON;
362 }
363
364 static void
popstring(void)365 popstring(void)
366 {
367 struct strpush *sp = parsefile->strpush;
368
369 INTOFF;
370 if (sp->ap) {
371 if (parsenextc != sp->ap->val &&
372 (parsenextc[-1] == ' ' || parsenextc[-1] == '\t'))
373 forcealias();
374 sp->ap->flag &= ~ALIASINUSE;
375 }
376 parsenextc = sp->prevstring;
377 parsenleft = sp->prevnleft;
378 parselleft = sp->prevlleft;
379 /*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/
380 parsefile->strpush = sp->prev;
381 if (sp != &(parsefile->basestrpush))
382 ckfree(sp);
383 INTON;
384 }
385
386 /*
387 * Set the input to take input from a file. If push is set, push the
388 * old input onto the stack first.
389 */
390
391 void
setinputfile(const char * fname,int push)392 setinputfile(const char *fname, int push)
393 {
394 int fd;
395 int fd2;
396
397 INTOFF;
398 if ((fd = open(fname, O_RDONLY | O_CLOEXEC)) < 0)
399 error("cannot open %s: %s", fname, strerror(errno));
400 if (fd < 10) {
401 fd2 = fcntl(fd, F_DUPFD_CLOEXEC, 10);
402 close(fd);
403 if (fd2 < 0)
404 error("Out of file descriptors");
405 fd = fd2;
406 }
407 setinputfd(fd, push);
408 INTON;
409 }
410
411
412 /*
413 * Like setinputfile, but takes an open file descriptor (which should have
414 * its FD_CLOEXEC flag already set). Call this with interrupts off.
415 */
416
417 void
setinputfd(int fd,int push)418 setinputfd(int fd, int push)
419 {
420 if (push) {
421 pushfile();
422 parsefile->buf = ckmalloc(BUFSIZ + 1);
423 }
424 if (parsefile->fd > 0)
425 close(parsefile->fd);
426 parsefile->fd = fd;
427 if (parsefile->buf == NULL)
428 parsefile->buf = ckmalloc(BUFSIZ + 1);
429 parselleft = parsenleft = 0;
430 plinno = 1;
431 }
432
433
434 /*
435 * Like setinputfile, but takes input from a string.
436 */
437
438 void
setinputstring(const char * string,int push)439 setinputstring(const char *string, int push)
440 {
441 INTOFF;
442 if (push)
443 pushfile();
444 parsenextc = string;
445 parselleft = parsenleft = strlen(string);
446 parsefile->buf = NULL;
447 plinno = 1;
448 INTON;
449 }
450
451
452
453 /*
454 * To handle the "." command, a stack of input files is used. Pushfile
455 * adds a new entry to the stack and popfile restores the previous level.
456 */
457
458 static void
pushfile(void)459 pushfile(void)
460 {
461 struct parsefile *pf;
462
463 parsefile->nleft = parsenleft;
464 parsefile->lleft = parselleft;
465 parsefile->nextc = parsenextc;
466 parsefile->linno = plinno;
467 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
468 pf->prev = parsefile;
469 pf->fd = -1;
470 pf->strpush = NULL;
471 pf->basestrpush.prev = NULL;
472 parsefile = pf;
473 }
474
475
476 void
popfile(void)477 popfile(void)
478 {
479 struct parsefile *pf = parsefile;
480
481 INTOFF;
482 if (pf->fd >= 0)
483 close(pf->fd);
484 if (pf->buf)
485 ckfree(pf->buf);
486 while (pf->strpush)
487 popstring();
488 parsefile = pf->prev;
489 ckfree(pf);
490 parsenleft = parsefile->nleft;
491 parselleft = parsefile->lleft;
492 parsenextc = parsefile->nextc;
493 plinno = parsefile->linno;
494 INTON;
495 }
496
497
498 /*
499 * Return current file (to go back to it later using popfilesupto()).
500 */
501
502 struct parsefile *
getcurrentfile(void)503 getcurrentfile(void)
504 {
505 return parsefile;
506 }
507
508
509 /*
510 * Pop files until the given file is on top again. Useful for regular
511 * builtins that read shell commands from files or strings.
512 * If the given file is not an active file, an error is raised.
513 */
514
515 void
popfilesupto(struct parsefile * file)516 popfilesupto(struct parsefile *file)
517 {
518 while (parsefile != file && parsefile != &basepf)
519 popfile();
520 if (parsefile != file)
521 error("popfilesupto() misused");
522 }
523
524 /*
525 * Return to top level.
526 */
527
528 void
popallfiles(void)529 popallfiles(void)
530 {
531 while (parsefile != &basepf)
532 popfile();
533 }
534
535
536
537 /*
538 * Close the file(s) that the shell is reading commands from. Called
539 * after a fork is done.
540 */
541
542 void
closescript(void)543 closescript(void)
544 {
545 popallfiles();
546 if (parsefile->fd > 0) {
547 close(parsefile->fd);
548 parsefile->fd = 0;
549 }
550 }
551