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: head/bin/sh/input.c 359398 2020-03-28 17:02:32Z kevans $");
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 #ifndef NO_HISTORY
63 #include "myhistedit.h"
64 #endif
65 #include "trap.h"
66
67 #define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */
68
69 struct strpush {
70 struct strpush *prev; /* preceding string on stack */
71 const char *prevstring;
72 int prevnleft;
73 int prevlleft;
74 struct alias *ap; /* if push was associated with an alias */
75 };
76
77 /*
78 * The parsefile structure pointed to by the global variable parsefile
79 * contains information about the current file being read.
80 */
81
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 const 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 static int parselleft; /* copy of parsefile->lleft */
98 const char *parsenextc; /* copy of parsefile->nextc */
99 static char basebuf[BUFSIZ + 1];/* buffer for top level input file */
100 static struct parsefile basepf = { /* top level input file */
101 .nextc = basebuf,
102 .buf = basebuf
103 };
104 static struct parsefile *parsefile = &basepf; /* current input file */
105 int whichprompt; /* 1 == PS1, 2 == PS2 */
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 /*
121 * Read a character from the script, returning PEOF on end of file.
122 * Nul characters in the input are silently discarded.
123 */
124
125 int
pgetc(void)126 pgetc(void)
127 {
128 return pgetc_macro();
129 }
130
131
132 static int
preadfd(void)133 preadfd(void)
134 {
135 int nr;
136 parsenextc = parsefile->buf;
137
138 retry:
139 #ifndef NO_HISTORY
140 if (parsefile->fd == 0 && el) {
141 static const char *rl_cp;
142 static int el_len;
143
144 if (rl_cp == NULL) {
145 el_resize(el);
146 rl_cp = el_gets(el, &el_len);
147 }
148 if (rl_cp == NULL)
149 nr = el_len == 0 ? 0 : -1;
150 else {
151 nr = el_len;
152 if (nr > BUFSIZ)
153 nr = BUFSIZ;
154 memcpy(parsefile->buf, rl_cp, nr);
155 if (nr != el_len) {
156 el_len -= nr;
157 rl_cp += nr;
158 } else
159 rl_cp = NULL;
160 }
161 } else
162 #endif
163 nr = read(parsefile->fd, parsefile->buf, BUFSIZ);
164
165 if (nr <= 0) {
166 if (nr < 0) {
167 if (errno == EINTR)
168 goto retry;
169 if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
170 int flags = fcntl(0, F_GETFL, 0);
171 if (flags >= 0 && flags & O_NONBLOCK) {
172 flags &=~ O_NONBLOCK;
173 if (fcntl(0, F_SETFL, flags) >= 0) {
174 out2fmt_flush("sh: turning off NDELAY mode\n");
175 goto retry;
176 }
177 }
178 }
179 }
180 nr = -1;
181 }
182 return nr;
183 }
184
185 /*
186 * Refill the input buffer and return the next input character:
187 *
188 * 1) If a string was pushed back on the input, pop it;
189 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
190 * from a string so we can't refill the buffer, return EOF.
191 * 3) If there is more in this buffer, use it else call read to fill it.
192 * 4) Process input up to the next newline, deleting nul characters.
193 */
194
195 int
preadbuffer(void)196 preadbuffer(void)
197 {
198 char *p, *q, *r, *end;
199 char savec;
200
201 while (parsefile->strpush) {
202 /*
203 * Add a space to the end of an alias to ensure that the
204 * alias remains in use while parsing its last word.
205 * This avoids alias recursions.
206 */
207 if (parsenleft == -1 && parsefile->strpush->ap != NULL)
208 return ' ';
209 popstring();
210 if (--parsenleft >= 0)
211 return (*parsenextc++);
212 }
213 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
214 return PEOF;
215
216 again:
217 if (parselleft <= 0) {
218 if ((parselleft = preadfd()) == -1) {
219 parselleft = parsenleft = EOF_NLEFT;
220 return PEOF;
221 }
222 }
223
224 p = parsefile->buf + (parsenextc - parsefile->buf);
225 end = p + parselleft;
226 *end = '\0';
227 q = strchrnul(p, '\n');
228 if (q != end && *q == '\0') {
229 /* delete nul characters */
230 for (r = q; q != end; q++) {
231 if (*q != '\0')
232 *r++ = *q;
233 }
234 parselleft -= end - r;
235 if (parselleft == 0)
236 goto again;
237 end = p + parselleft;
238 *end = '\0';
239 q = strchrnul(p, '\n');
240 }
241 if (q == end) {
242 parsenleft = parselleft;
243 parselleft = 0;
244 } else /* *q == '\n' */ {
245 q++;
246 parsenleft = q - parsenextc;
247 parselleft -= parsenleft;
248 }
249 parsenleft--;
250
251 savec = *q;
252 *q = '\0';
253
254 #ifndef NO_HISTORY
255 if (parsefile->fd == 0 && hist &&
256 parsenextc[strspn(parsenextc, " \t\n")] != '\0') {
257 HistEvent he;
258 INTOFF;
259 history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
260 parsenextc);
261 INTON;
262 }
263 #endif
264
265 if (vflag) {
266 out2str(parsenextc);
267 flushout(out2);
268 }
269
270 *q = savec;
271
272 return *parsenextc++;
273 }
274
275 /*
276 * Returns if we are certain we are at EOF. Does not cause any more input
277 * to be read from the outside world.
278 */
279
280 int
preadateof(void)281 preadateof(void)
282 {
283 if (parsenleft > 0)
284 return 0;
285 if (parsefile->strpush)
286 return 0;
287 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
288 return 1;
289 return 0;
290 }
291
292 /*
293 * Undo the last call to pgetc. Only one character may be pushed back.
294 * PEOF may be pushed back.
295 */
296
297 void
pungetc(void)298 pungetc(void)
299 {
300 parsenleft++;
301 parsenextc--;
302 }
303
304 /*
305 * Push a string back onto the input at this current parsefile level.
306 * We handle aliases this way.
307 */
308 void
pushstring(const char * s,int len,struct alias * ap)309 pushstring(const char *s, int len, struct alias *ap)
310 {
311 struct strpush *sp;
312
313 INTOFF;
314 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
315 if (parsefile->strpush) {
316 sp = ckmalloc(sizeof (struct strpush));
317 sp->prev = parsefile->strpush;
318 parsefile->strpush = sp;
319 } else
320 sp = parsefile->strpush = &(parsefile->basestrpush);
321 sp->prevstring = parsenextc;
322 sp->prevnleft = parsenleft;
323 sp->prevlleft = parselleft;
324 sp->ap = ap;
325 if (ap)
326 ap->flag |= ALIASINUSE;
327 parsenextc = s;
328 parsenleft = len;
329 INTON;
330 }
331
332 static void
popstring(void)333 popstring(void)
334 {
335 struct strpush *sp = parsefile->strpush;
336
337 INTOFF;
338 if (sp->ap) {
339 if (parsenextc != sp->ap->val &&
340 (parsenextc[-1] == ' ' || parsenextc[-1] == '\t'))
341 forcealias();
342 sp->ap->flag &= ~ALIASINUSE;
343 }
344 parsenextc = sp->prevstring;
345 parsenleft = sp->prevnleft;
346 parselleft = sp->prevlleft;
347 /*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/
348 parsefile->strpush = sp->prev;
349 if (sp != &(parsefile->basestrpush))
350 ckfree(sp);
351 INTON;
352 }
353
354 /*
355 * Set the input to take input from a file. If push is set, push the
356 * old input onto the stack first.
357 */
358
359 void
setinputfile(const char * fname,int push)360 setinputfile(const char *fname, int push)
361 {
362 int e;
363 int fd;
364 int fd2;
365
366 INTOFF;
367 if ((fd = open(fname, O_RDONLY | O_CLOEXEC_MAYBE)) < 0) {
368 e = errno;
369 errorwithstatus(e == ENOENT || e == ENOTDIR ? 127 : 126,
370 "cannot open %s: %s", fname, strerror(e));
371 }
372 if (fd < 10) {
373 fd2 = fcntl(fd, F_DUPFD_CLOEXEC_MAYBE, 10);
374 close(fd);
375 if (fd2 < 0)
376 error("Out of file descriptors");
377 fd = fd2;
378 }
379 setinputfd(fd, push);
380 INTON;
381 }
382
383
384 /*
385 * Like setinputfile, but takes an open file descriptor (which should have
386 * its FD_CLOEXEC flag already set). Call this with interrupts off.
387 */
388
389 void
setinputfd(int fd,int push)390 setinputfd(int fd, int push)
391 {
392 #if !defined(O_CLOEXEC) || !defined(F_DUPFD_CLOEXEC)
393 fcntl(fd, F_SETFD, FD_CLOEXEC);
394 #endif
395 if (push) {
396 pushfile();
397 parsefile->buf = ckmalloc(BUFSIZ + 1);
398 }
399 if (parsefile->fd > 0)
400 close(parsefile->fd);
401 parsefile->fd = fd;
402 if (parsefile->buf == NULL)
403 parsefile->buf = ckmalloc(BUFSIZ + 1);
404 parselleft = parsenleft = 0;
405 plinno = 1;
406 }
407
408
409 /*
410 * Like setinputfile, but takes input from a string.
411 */
412
413 void
setinputstring(const char * string,int push)414 setinputstring(const char *string, int push)
415 {
416 INTOFF;
417 if (push)
418 pushfile();
419 parsenextc = string;
420 parselleft = parsenleft = strlen(string);
421 parsefile->buf = NULL;
422 plinno = 1;
423 INTON;
424 }
425
426
427
428 /*
429 * To handle the "." command, a stack of input files is used. Pushfile
430 * adds a new entry to the stack and popfile restores the previous level.
431 */
432
433 static void
pushfile(void)434 pushfile(void)
435 {
436 struct parsefile *pf;
437
438 parsefile->nleft = parsenleft;
439 parsefile->lleft = parselleft;
440 parsefile->nextc = parsenextc;
441 parsefile->linno = plinno;
442 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
443 pf->prev = parsefile;
444 pf->fd = -1;
445 pf->strpush = NULL;
446 pf->basestrpush.prev = NULL;
447 parsefile = pf;
448 }
449
450
451 void
popfile(void)452 popfile(void)
453 {
454 struct parsefile *pf = parsefile;
455
456 INTOFF;
457 if (pf->fd >= 0)
458 close(pf->fd);
459 if (pf->buf)
460 ckfree(pf->buf);
461 while (pf->strpush)
462 popstring();
463 parsefile = pf->prev;
464 ckfree(pf);
465 parsenleft = parsefile->nleft;
466 parselleft = parsefile->lleft;
467 parsenextc = parsefile->nextc;
468 plinno = parsefile->linno;
469 INTON;
470 }
471
472
473 /*
474 * Return current file (to go back to it later using popfilesupto()).
475 */
476
477 struct parsefile *
getcurrentfile(void)478 getcurrentfile(void)
479 {
480 return parsefile;
481 }
482
483
484 /*
485 * Pop files until the given file is on top again. Useful for regular
486 * builtins that read shell commands from files or strings.
487 * If the given file is not an active file, an error is raised.
488 */
489
490 void
popfilesupto(struct parsefile * file)491 popfilesupto(struct parsefile *file)
492 {
493 while (parsefile != file && parsefile != &basepf)
494 popfile();
495 if (parsefile != file)
496 error("popfilesupto() misused");
497 }
498
499 /*
500 * Return to top level.
501 */
502
503 void
popallfiles(void)504 popallfiles(void)
505 {
506 while (parsefile != &basepf)
507 popfile();
508 }
509
510
511
512 /*
513 * Close the file(s) that the shell is reading commands from. Called
514 * after a fork is done.
515 */
516
517 void
closescript(void)518 closescript(void)
519 {
520 popallfiles();
521 if (parsefile->fd > 0) {
522 close(parsefile->fd);
523 parsefile->fd = 0;
524 }
525 }
526