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 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 /*
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 fd;
363 int fd2;
364
365 INTOFF;
366 if ((fd = open(fname, O_RDONLY | O_CLOEXEC)) < 0)
367 error("cannot open %s: %s", fname, strerror(errno));
368 if (fd < 10) {
369 fd2 = fcntl(fd, F_DUPFD_CLOEXEC, 10);
370 close(fd);
371 if (fd2 < 0)
372 error("Out of file descriptors");
373 fd = fd2;
374 }
375 setinputfd(fd, push);
376 INTON;
377 }
378
379
380 /*
381 * Like setinputfile, but takes an open file descriptor (which should have
382 * its FD_CLOEXEC flag already set). Call this with interrupts off.
383 */
384
385 void
setinputfd(int fd,int push)386 setinputfd(int fd, int push)
387 {
388 if (push) {
389 pushfile();
390 parsefile->buf = ckmalloc(BUFSIZ + 1);
391 }
392 if (parsefile->fd > 0)
393 close(parsefile->fd);
394 parsefile->fd = fd;
395 if (parsefile->buf == NULL)
396 parsefile->buf = ckmalloc(BUFSIZ + 1);
397 parselleft = parsenleft = 0;
398 plinno = 1;
399 }
400
401
402 /*
403 * Like setinputfile, but takes input from a string.
404 */
405
406 void
setinputstring(const char * string,int push)407 setinputstring(const char *string, int push)
408 {
409 INTOFF;
410 if (push)
411 pushfile();
412 parsenextc = string;
413 parselleft = parsenleft = strlen(string);
414 parsefile->buf = NULL;
415 plinno = 1;
416 INTON;
417 }
418
419
420
421 /*
422 * To handle the "." command, a stack of input files is used. Pushfile
423 * adds a new entry to the stack and popfile restores the previous level.
424 */
425
426 static void
pushfile(void)427 pushfile(void)
428 {
429 struct parsefile *pf;
430
431 parsefile->nleft = parsenleft;
432 parsefile->lleft = parselleft;
433 parsefile->nextc = parsenextc;
434 parsefile->linno = plinno;
435 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
436 pf->prev = parsefile;
437 pf->fd = -1;
438 pf->strpush = NULL;
439 pf->basestrpush.prev = NULL;
440 parsefile = pf;
441 }
442
443
444 void
popfile(void)445 popfile(void)
446 {
447 struct parsefile *pf = parsefile;
448
449 INTOFF;
450 if (pf->fd >= 0)
451 close(pf->fd);
452 if (pf->buf)
453 ckfree(pf->buf);
454 while (pf->strpush)
455 popstring();
456 parsefile = pf->prev;
457 ckfree(pf);
458 parsenleft = parsefile->nleft;
459 parselleft = parsefile->lleft;
460 parsenextc = parsefile->nextc;
461 plinno = parsefile->linno;
462 INTON;
463 }
464
465
466 /*
467 * Return current file (to go back to it later using popfilesupto()).
468 */
469
470 struct parsefile *
getcurrentfile(void)471 getcurrentfile(void)
472 {
473 return parsefile;
474 }
475
476
477 /*
478 * Pop files until the given file is on top again. Useful for regular
479 * builtins that read shell commands from files or strings.
480 * If the given file is not an active file, an error is raised.
481 */
482
483 void
popfilesupto(struct parsefile * file)484 popfilesupto(struct parsefile *file)
485 {
486 while (parsefile != file && parsefile != &basepf)
487 popfile();
488 if (parsefile != file)
489 error("popfilesupto() misused");
490 }
491
492 /*
493 * Return to top level.
494 */
495
496 void
popallfiles(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
closescript(void)511 closescript(void)
512 {
513 popallfiles();
514 if (parsefile->fd > 0) {
515 close(parsefile->fd);
516 parsefile->fd = 0;
517 }
518 }
519