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