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 #include <stdio.h> /* defines BUFSIZ */
40 #include <fcntl.h>
41 #include <errno.h>
42 #include <unistd.h>
43 #include <stdlib.h>
44 #include <string.h>
45
46 /*
47 * This file implements the input routines used by the parser.
48 */
49
50 #include "shell.h"
51 #include "redir.h"
52 #include "syntax.h"
53 #include "input.h"
54 #include "output.h"
55 #include "options.h"
56 #include "memalloc.h"
57 #include "error.h"
58 #include "alias.h"
59 #include "parser.h"
60 #include "myhistedit.h"
61 #include "trap.h"
62
63 #define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */
64
65 struct strpush {
66 struct strpush *prev; /* preceding string on stack */
67 const char *prevstring;
68 int prevnleft;
69 int prevlleft;
70 struct alias *ap; /* if push was associated with an alias */
71 };
72
73 /*
74 * The parsefile structure pointed to by the global variable parsefile
75 * contains information about the current file being read.
76 */
77
78 struct parsefile {
79 struct parsefile *prev; /* preceding file on stack */
80 int linno; /* current line */
81 int fd; /* file descriptor (or -1 if string) */
82 int nleft; /* number of chars left in this line */
83 int lleft; /* number of lines left in this buffer */
84 const char *nextc; /* next char in buffer */
85 char *buf; /* input buffer */
86 struct strpush *strpush; /* for pushing strings at this level */
87 struct strpush basestrpush; /* so pushing one is fast */
88 };
89
90
91 int plinno = 1; /* input line number */
92 int parsenleft; /* copy of parsefile->nleft */
93 static int parselleft; /* copy of parsefile->lleft */
94 const char *parsenextc; /* copy of parsefile->nextc */
95 static char basebuf[BUFSIZ + 1];/* buffer for top level input file */
96 static struct parsefile basepf = { /* top level input file */
97 .nextc = basebuf,
98 .buf = basebuf
99 };
100 static struct parsefile *parsefile = &basepf; /* current input file */
101 int whichprompt; /* 1 == PS1, 2 == PS2 */
102
103 static void pushfile(void);
104 static int preadfd(void);
105 static void popstring(void);
106
107 void
resetinput(void)108 resetinput(void)
109 {
110 popallfiles();
111 parselleft = parsenleft = 0; /* clear input buffer */
112 }
113
114
115
116 /*
117 * Read a character from the script, returning PEOF on end of file.
118 * Nul characters in the input are silently discarded.
119 */
120
121 int
pgetc(void)122 pgetc(void)
123 {
124 return pgetc_macro();
125 }
126
127
128 static int
preadfd(void)129 preadfd(void)
130 {
131 int nr;
132 parsenextc = parsefile->buf;
133
134 retry:
135 #ifndef NO_HISTORY
136 if (parsefile->fd == 0 && el) {
137 static const char *rl_cp;
138 static int el_len;
139
140 if (rl_cp == NULL) {
141 el_resize(el);
142 rl_cp = el_gets(el, &el_len);
143 }
144 if (rl_cp == NULL)
145 nr = el_len == 0 ? 0 : -1;
146 else {
147 nr = el_len;
148 if (nr > BUFSIZ)
149 nr = BUFSIZ;
150 memcpy(parsefile->buf, rl_cp, nr);
151 if (nr != el_len) {
152 el_len -= nr;
153 rl_cp += nr;
154 } else
155 rl_cp = NULL;
156 }
157 } else
158 #endif
159 nr = read(parsefile->fd, parsefile->buf, BUFSIZ);
160
161 if (nr <= 0) {
162 if (nr < 0) {
163 if (errno == EINTR)
164 goto retry;
165 if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
166 int flags = fcntl(0, F_GETFL, 0);
167 if (flags >= 0 && flags & O_NONBLOCK) {
168 flags &=~ O_NONBLOCK;
169 if (fcntl(0, F_SETFL, flags) >= 0) {
170 out2fmt_flush("sh: turning off NDELAY mode\n");
171 goto retry;
172 }
173 }
174 }
175 }
176 nr = -1;
177 }
178 return nr;
179 }
180
181 /*
182 * Refill the input buffer and return the next input character:
183 *
184 * 1) If a string was pushed back on the input, pop it;
185 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
186 * from a string so we can't refill the buffer, return EOF.
187 * 3) If there is more in this buffer, use it else call read to fill it.
188 * 4) Process input up to the next newline, deleting nul characters.
189 */
190
191 int
preadbuffer(void)192 preadbuffer(void)
193 {
194 char *p, *q, *r, *end;
195 char savec;
196
197 while (parsefile->strpush) {
198 /*
199 * Add a space to the end of an alias to ensure that the
200 * alias remains in use while parsing its last word.
201 * This avoids alias recursions.
202 */
203 if (parsenleft == -1 && parsefile->strpush->ap != NULL)
204 return ' ';
205 popstring();
206 if (--parsenleft >= 0)
207 return (*parsenextc++);
208 }
209 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
210 return PEOF;
211
212 again:
213 if (parselleft <= 0) {
214 if ((parselleft = preadfd()) == -1) {
215 parselleft = parsenleft = EOF_NLEFT;
216 return PEOF;
217 }
218 }
219
220 p = parsefile->buf + (parsenextc - parsefile->buf);
221 end = p + parselleft;
222 *end = '\0';
223 q = strchrnul(p, '\n');
224 if (q != end && *q == '\0') {
225 /* delete nul characters */
226 for (r = q; q != end; q++) {
227 if (*q != '\0')
228 *r++ = *q;
229 }
230 parselleft -= end - r;
231 if (parselleft == 0)
232 goto again;
233 end = p + parselleft;
234 *end = '\0';
235 q = strchrnul(p, '\n');
236 }
237 if (q == end) {
238 parsenleft = parselleft;
239 parselleft = 0;
240 } else /* *q == '\n' */ {
241 q++;
242 parsenleft = q - parsenextc;
243 parselleft -= parsenleft;
244 }
245 parsenleft--;
246
247 savec = *q;
248 *q = '\0';
249
250 #ifndef NO_HISTORY
251 if (parsefile->fd == 0 && hist &&
252 parsenextc[strspn(parsenextc, " \t\n")] != '\0') {
253 HistEvent he;
254 INTOFF;
255 history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
256 parsenextc);
257 INTON;
258 }
259 #endif
260
261 if (vflag) {
262 out2str(parsenextc);
263 flushout(out2);
264 }
265
266 *q = savec;
267
268 return *parsenextc++;
269 }
270
271 /*
272 * Returns if we are certain we are at EOF. Does not cause any more input
273 * to be read from the outside world.
274 */
275
276 int
preadateof(void)277 preadateof(void)
278 {
279 if (parsenleft > 0)
280 return 0;
281 if (parsefile->strpush)
282 return 0;
283 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
284 return 1;
285 return 0;
286 }
287
288 /*
289 * Undo the last call to pgetc. Only one character may be pushed back.
290 * PEOF may be pushed back.
291 */
292
293 void
pungetc(void)294 pungetc(void)
295 {
296 parsenleft++;
297 parsenextc--;
298 }
299
300 /*
301 * Push a string back onto the input at this current parsefile level.
302 * We handle aliases this way.
303 */
304 void
pushstring(const char * s,int len,struct alias * ap)305 pushstring(const char *s, int len, struct alias *ap)
306 {
307 struct strpush *sp;
308
309 INTOFF;
310 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
311 if (parsefile->strpush) {
312 sp = ckmalloc(sizeof (struct strpush));
313 sp->prev = parsefile->strpush;
314 parsefile->strpush = sp;
315 } else
316 sp = parsefile->strpush = &(parsefile->basestrpush);
317 sp->prevstring = parsenextc;
318 sp->prevnleft = parsenleft;
319 sp->prevlleft = parselleft;
320 sp->ap = ap;
321 if (ap)
322 ap->flag |= ALIASINUSE;
323 parsenextc = s;
324 parsenleft = len;
325 INTON;
326 }
327
328 static void
popstring(void)329 popstring(void)
330 {
331 struct strpush *sp = parsefile->strpush;
332
333 INTOFF;
334 if (sp->ap) {
335 if (parsenextc != sp->ap->val &&
336 (parsenextc[-1] == ' ' || parsenextc[-1] == '\t'))
337 forcealias();
338 sp->ap->flag &= ~ALIASINUSE;
339 }
340 parsenextc = sp->prevstring;
341 parsenleft = sp->prevnleft;
342 parselleft = sp->prevlleft;
343 /*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/
344 parsefile->strpush = sp->prev;
345 if (sp != &(parsefile->basestrpush))
346 ckfree(sp);
347 INTON;
348 }
349
350 /*
351 * Set the input to take input from a file. If push is set, push the
352 * old input onto the stack first.
353 */
354
355 void
setinputfile(const char * fname,int push)356 setinputfile(const char *fname, int push)
357 {
358 int e;
359 int fd;
360 int fd2;
361
362 INTOFF;
363 if ((fd = open(fname, O_RDONLY | O_CLOEXEC)) < 0) {
364 e = errno;
365 errorwithstatus(e == ENOENT || e == ENOTDIR ? 127 : 126,
366 "cannot open %s: %s", fname, strerror(e));
367 }
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