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 #include <stdio.h> /* defines BUFSIZ */
34 #include <fcntl.h>
35 #include <errno.h>
36 #include <unistd.h>
37 #include <stdlib.h>
38 #include <string.h>
39
40 /*
41 * This file implements the input routines used by the parser.
42 */
43
44 #include "shell.h"
45 #include "redir.h"
46 #include "syntax.h"
47 #include "input.h"
48 #include "output.h"
49 #include "options.h"
50 #include "memalloc.h"
51 #include "error.h"
52 #include "alias.h"
53 #include "parser.h"
54 #ifndef NO_HISTORY
55 #include "myhistedit.h"
56 #endif
57 #include "trap.h"
58
59 #define EOF_NLEFT -99 /* value of parsenleft when EOF pushed back */
60
61 struct strpush {
62 struct strpush *prev; /* preceding string on stack */
63 const char *prevstring;
64 int prevnleft;
65 int prevlleft;
66 struct alias *ap; /* if push was associated with an alias */
67 };
68
69 /*
70 * The parsefile structure pointed to by the global variable parsefile
71 * contains information about the current file being read.
72 */
73
74 struct parsefile {
75 struct parsefile *prev; /* preceding file on stack */
76 int linno; /* current line */
77 int fd; /* file descriptor (or -1 if string) */
78 int nleft; /* number of chars left in this line */
79 int lleft; /* number of lines left in this buffer */
80 const char *nextc; /* next char in buffer */
81 char *buf; /* input buffer */
82 struct strpush *strpush; /* for pushing strings at this level */
83 struct strpush basestrpush; /* so pushing one is fast */
84 };
85
86
87 int plinno = 1; /* input line number */
88 int parsenleft; /* copy of parsefile->nleft */
89 static int parselleft; /* copy of parsefile->lleft */
90 const char *parsenextc; /* copy of parsefile->nextc */
91 static char basebuf[BUFSIZ + 1];/* buffer for top level input file */
92 static struct parsefile basepf = { /* top level input file */
93 .nextc = basebuf,
94 .buf = basebuf
95 };
96 static struct parsefile *parsefile = &basepf; /* current input file */
97 int whichprompt; /* 1 == PS1, 2 == PS2 */
98
99 static void pushfile(void);
100 static int preadfd(void);
101 static void popstring(void);
102
103 void
resetinput(void)104 resetinput(void)
105 {
106 popallfiles();
107 parselleft = parsenleft = 0; /* clear input buffer */
108 }
109
110
111
112 /*
113 * Read a character from the script, returning PEOF on end of file.
114 * Nul characters in the input are silently discarded.
115 */
116
117 int
pgetc(void)118 pgetc(void)
119 {
120 return pgetc_macro();
121 }
122
123
124 static int
preadfd(void)125 preadfd(void)
126 {
127 int nr;
128 parsenextc = parsefile->buf;
129
130 retry:
131 #ifndef NO_HISTORY
132 if (parsefile->fd == 0 && el) {
133 static const char *rl_cp;
134 static int el_len;
135
136 if (rl_cp == NULL) {
137 el_resize(el);
138 rl_cp = el_gets(el, &el_len);
139 }
140 if (rl_cp == NULL)
141 nr = el_len == 0 ? 0 : -1;
142 else {
143 nr = el_len;
144 if (nr > BUFSIZ)
145 nr = BUFSIZ;
146 memcpy(parsefile->buf, rl_cp, nr);
147 if (nr != el_len) {
148 el_len -= nr;
149 rl_cp += nr;
150 } else
151 rl_cp = NULL;
152 }
153 } else
154 #endif
155 nr = read(parsefile->fd, parsefile->buf, BUFSIZ);
156
157 if (nr <= 0) {
158 if (nr < 0) {
159 if (errno == EINTR)
160 goto retry;
161 if (parsefile->fd == 0 && errno == EWOULDBLOCK) {
162 int flags = fcntl(0, F_GETFL, 0);
163 if (flags >= 0 && flags & O_NONBLOCK) {
164 flags &=~ O_NONBLOCK;
165 if (fcntl(0, F_SETFL, flags) >= 0) {
166 out2fmt_flush("sh: turning off NDELAY mode\n");
167 goto retry;
168 }
169 }
170 }
171 }
172 nr = -1;
173 }
174 return nr;
175 }
176
177 /*
178 * Refill the input buffer and return the next input character:
179 *
180 * 1) If a string was pushed back on the input, pop it;
181 * 2) If an EOF was pushed back (parsenleft == EOF_NLEFT) or we are reading
182 * from a string so we can't refill the buffer, return EOF.
183 * 3) If there is more in this buffer, use it else call read to fill it.
184 * 4) Process input up to the next newline, deleting nul characters.
185 */
186
187 int
preadbuffer(void)188 preadbuffer(void)
189 {
190 char *p, *q, *r, *end;
191 char savec;
192
193 while (parsefile->strpush) {
194 /*
195 * Add a space to the end of an alias to ensure that the
196 * alias remains in use while parsing its last word.
197 * This avoids alias recursions.
198 */
199 if (parsenleft == -1 && parsefile->strpush->ap != NULL)
200 return ' ';
201 popstring();
202 if (--parsenleft >= 0)
203 return (*parsenextc++);
204 }
205 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
206 return PEOF;
207
208 again:
209 if (parselleft <= 0) {
210 if ((parselleft = preadfd()) == -1) {
211 parselleft = parsenleft = EOF_NLEFT;
212 return PEOF;
213 }
214 }
215
216 p = parsefile->buf + (parsenextc - parsefile->buf);
217 end = p + parselleft;
218 *end = '\0';
219 q = strchrnul(p, '\n');
220 if (q != end && *q == '\0') {
221 /* delete nul characters */
222 for (r = q; q != end; q++) {
223 if (*q != '\0')
224 *r++ = *q;
225 }
226 parselleft -= end - r;
227 if (parselleft == 0)
228 goto again;
229 end = p + parselleft;
230 *end = '\0';
231 q = strchrnul(p, '\n');
232 }
233 if (q == end) {
234 parsenleft = parselleft;
235 parselleft = 0;
236 } else /* *q == '\n' */ {
237 q++;
238 parsenleft = q - parsenextc;
239 parselleft -= parsenleft;
240 }
241 parsenleft--;
242
243 savec = *q;
244 *q = '\0';
245
246 #ifndef NO_HISTORY
247 if (parsefile->fd == 0 && hist &&
248 parsenextc[strspn(parsenextc, " \t\n")] != '\0') {
249 HistEvent he;
250 INTOFF;
251 history(hist, &he, whichprompt == 1 ? H_ENTER : H_ADD,
252 parsenextc);
253 INTON;
254 }
255 #endif
256
257 if (vflag) {
258 out2str(parsenextc);
259 flushout(out2);
260 }
261
262 *q = savec;
263
264 return *parsenextc++;
265 }
266
267 /*
268 * Returns if we are certain we are at EOF. Does not cause any more input
269 * to be read from the outside world.
270 */
271
272 int
preadateof(void)273 preadateof(void)
274 {
275 if (parsenleft > 0)
276 return 0;
277 if (parsefile->strpush)
278 return 0;
279 if (parsenleft == EOF_NLEFT || parsefile->buf == NULL)
280 return 1;
281 return 0;
282 }
283
284 /*
285 * Undo the last call to pgetc. Only one character may be pushed back.
286 * PEOF may be pushed back.
287 */
288
289 void
pungetc(void)290 pungetc(void)
291 {
292 parsenleft++;
293 parsenextc--;
294 }
295
296 /*
297 * Push a string back onto the input at this current parsefile level.
298 * We handle aliases this way.
299 */
300 void
pushstring(const char * s,int len,struct alias * ap)301 pushstring(const char *s, int len, struct alias *ap)
302 {
303 struct strpush *sp;
304
305 INTOFF;
306 /*out2fmt_flush("*** calling pushstring: %s, %d\n", s, len);*/
307 if (parsefile->strpush) {
308 sp = ckmalloc(sizeof (struct strpush));
309 sp->prev = parsefile->strpush;
310 parsefile->strpush = sp;
311 } else
312 sp = parsefile->strpush = &(parsefile->basestrpush);
313 sp->prevstring = parsenextc;
314 sp->prevnleft = parsenleft;
315 sp->prevlleft = parselleft;
316 sp->ap = ap;
317 if (ap)
318 ap->flag |= ALIASINUSE;
319 parsenextc = s;
320 parsenleft = len;
321 INTON;
322 }
323
324 static void
popstring(void)325 popstring(void)
326 {
327 struct strpush *sp = parsefile->strpush;
328
329 INTOFF;
330 if (sp->ap) {
331 if (parsenextc != sp->ap->val &&
332 (parsenextc[-1] == ' ' || parsenextc[-1] == '\t'))
333 forcealias();
334 sp->ap->flag &= ~ALIASINUSE;
335 }
336 parsenextc = sp->prevstring;
337 parsenleft = sp->prevnleft;
338 parselleft = sp->prevlleft;
339 /*out2fmt_flush("*** calling popstring: restoring to '%s'\n", parsenextc);*/
340 parsefile->strpush = sp->prev;
341 if (sp != &(parsefile->basestrpush))
342 ckfree(sp);
343 INTON;
344 }
345
346 /*
347 * Set the input to take input from a file. If push is set, push the
348 * old input onto the stack first.
349 * About verify:
350 * -1: Obey verifyflag
351 * 0: Do not verify
352 * 1: Do verify
353 */
354
355 void
setinputfile(const char * fname,int push,int verify)356 setinputfile(const char *fname, int push, int verify)
357 {
358 int e;
359 int fd;
360 int fd2;
361 int oflags = O_RDONLY | O_CLOEXEC;
362
363 if (verify == 1 || (verify == -1 && verifyflag))
364 oflags |= O_VERIFY;
365
366 INTOFF;
367 if ((fd = open(fname, oflags)) < 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, 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 (push) {
393 pushfile();
394 parsefile->buf = ckmalloc(BUFSIZ + 1);
395 }
396 if (parsefile->fd > 0)
397 close(parsefile->fd);
398 parsefile->fd = fd;
399 if (parsefile->buf == NULL)
400 parsefile->buf = ckmalloc(BUFSIZ + 1);
401 parselleft = parsenleft = 0;
402 plinno = 1;
403 }
404
405
406 /*
407 * Like setinputfile, but takes input from a string.
408 */
409
410 void
setinputstring(const char * string,int push)411 setinputstring(const char *string, int push)
412 {
413 INTOFF;
414 if (push)
415 pushfile();
416 parsenextc = string;
417 parselleft = parsenleft = strlen(string);
418 parsefile->buf = NULL;
419 plinno = 1;
420 INTON;
421 }
422
423
424
425 /*
426 * To handle the "." command, a stack of input files is used. Pushfile
427 * adds a new entry to the stack and popfile restores the previous level.
428 */
429
430 static void
pushfile(void)431 pushfile(void)
432 {
433 struct parsefile *pf;
434
435 parsefile->nleft = parsenleft;
436 parsefile->lleft = parselleft;
437 parsefile->nextc = parsenextc;
438 parsefile->linno = plinno;
439 pf = (struct parsefile *)ckmalloc(sizeof (struct parsefile));
440 pf->prev = parsefile;
441 pf->fd = -1;
442 pf->strpush = NULL;
443 pf->basestrpush.prev = NULL;
444 parsefile = pf;
445 }
446
447
448 void
popfile(void)449 popfile(void)
450 {
451 struct parsefile *pf = parsefile;
452
453 INTOFF;
454 if (pf->fd >= 0)
455 close(pf->fd);
456 if (pf->buf)
457 ckfree(pf->buf);
458 while (pf->strpush)
459 popstring();
460 parsefile = pf->prev;
461 ckfree(pf);
462 parsenleft = parsefile->nleft;
463 parselleft = parsefile->lleft;
464 parsenextc = parsefile->nextc;
465 plinno = parsefile->linno;
466 INTON;
467 }
468
469
470 /*
471 * Return current file (to go back to it later using popfilesupto()).
472 */
473
474 struct parsefile *
getcurrentfile(void)475 getcurrentfile(void)
476 {
477 return parsefile;
478 }
479
480
481 /*
482 * Pop files until the given file is on top again. Useful for regular
483 * builtins that read shell commands from files or strings.
484 * If the given file is not an active file, an error is raised.
485 */
486
487 void
popfilesupto(struct parsefile * file)488 popfilesupto(struct parsefile *file)
489 {
490 while (parsefile != file && parsefile != &basepf)
491 popfile();
492 if (parsefile != file)
493 error("popfilesupto() misused");
494 }
495
496 /*
497 * Return to top level.
498 */
499
500 void
popallfiles(void)501 popallfiles(void)
502 {
503 while (parsefile != &basepf)
504 popfile();
505 }
506
507
508
509 /*
510 * Close the file(s) that the shell is reading commands from. Called
511 * after a fork is done.
512 */
513
514 void
closescript(void)515 closescript(void)
516 {
517 popallfiles();
518 if (parsefile->fd > 0) {
519 close(parsefile->fd);
520 parsefile->fd = 0;
521 }
522 }
523