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Commit | Line | Data |
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726f6388 JA |
1 | /* input.c -- functions to perform buffered input with synchronization. */ |
2 | ||
3 | /* Copyright (C) 1992 Free Software Foundation, Inc. | |
4 | ||
5 | This file is part of GNU Bash, the Bourne Again SHell. | |
6 | ||
7 | Bash is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 2, or (at your option) any later | |
10 | version. | |
11 | ||
12 | Bash is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License along | |
18 | with Bash; see the file COPYING. If not, write to the Free Software | |
19 | Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
20 | ||
ccc6cda3 | 21 | #include "config.h" |
726f6388 JA |
22 | |
23 | #include "bashtypes.h" | |
24 | #include <sys/file.h> | |
25 | #include "filecntl.h" | |
26 | #include "posixstat.h" | |
27 | #include <stdio.h> | |
28 | #include <errno.h> | |
29 | ||
ccc6cda3 JA |
30 | #if defined (HAVE_UNISTD_H) |
31 | # include <unistd.h> | |
32 | #endif | |
33 | ||
726f6388 | 34 | #include "bashansi.h" |
726f6388 JA |
35 | #include "command.h" |
36 | #include "general.h" | |
37 | #include "input.h" | |
ccc6cda3 JA |
38 | #include "error.h" |
39 | #include "externs.h" | |
726f6388 JA |
40 | |
41 | #if !defined (errno) | |
42 | extern int errno; | |
43 | #endif /* !errno */ | |
44 | ||
ccc6cda3 JA |
45 | /* Functions to handle reading input on systems that don't restart read(2) |
46 | if a signal is received. */ | |
47 | ||
48 | #if !defined (HAVE_RESTARTABLE_SYSCALLS) | |
49 | static unsigned char localbuf[128]; | |
50 | static int local_index, local_bufused; | |
51 | ||
52 | /* Posix and USG systems do not guarantee to restart read () if it is | |
53 | interrupted by a signal. We do the read ourselves, and restart it | |
54 | if it returns EINTR. */ | |
55 | int | |
56 | getc_with_restart (stream) | |
57 | FILE *stream; | |
58 | { | |
59 | /* Try local buffering to reduce the number of read(2) calls. */ | |
60 | if (local_index == local_bufused || local_bufused == 0) | |
61 | { | |
62 | while (1) | |
63 | { | |
64 | local_bufused = read (fileno (stream), localbuf, sizeof(localbuf)); | |
65 | if (local_bufused > 0) | |
66 | break; | |
67 | else if (local_bufused == 0 || errno != EINTR) | |
68 | { | |
69 | local_index = 0; | |
70 | return EOF; | |
71 | } | |
72 | } | |
73 | local_index = 0; | |
74 | } | |
75 | return (localbuf[local_index++]); | |
76 | } | |
77 | ||
78 | int | |
79 | ungetc_with_restart (c, stream) | |
80 | int c; | |
81 | FILE *stream; | |
82 | { | |
83 | if (local_index == 0 || c == EOF) | |
84 | return EOF; | |
85 | return (localbuf[--local_index] = c); | |
86 | } | |
87 | #endif /* !HAVE_RESTARTABLE_SYSCALLS */ | |
88 | ||
89 | #if defined (BUFFERED_INPUT) | |
90 | ||
91 | /* A facility similar to stdio, but input-only. */ | |
92 | ||
726f6388 JA |
93 | #define MAX_INPUT_BUFFER_SIZE 8192 |
94 | ||
95 | #if !defined (SEEK_CUR) | |
96 | # define SEEK_CUR 1 | |
97 | #endif /* !SEEK_CUR */ | |
98 | ||
99 | void free_buffered_stream (); | |
100 | ||
ccc6cda3 JA |
101 | extern int return_EOF (); |
102 | ||
726f6388 JA |
103 | extern int interactive_shell; |
104 | ||
105 | int bash_input_fd_changed; | |
ccc6cda3 | 106 | |
726f6388 JA |
107 | /* This provides a way to map from a file descriptor to the buffer |
108 | associated with that file descriptor, rather than just the other | |
109 | way around. This is needed so that buffers are managed properly | |
110 | in constructs like 3<&4. buffers[x]->b_fd == x -- that is how the | |
111 | correspondence is maintained. */ | |
112 | BUFFERED_STREAM **buffers = (BUFFERED_STREAM **)NULL; | |
ccc6cda3 | 113 | static int nbuffers; |
726f6388 JA |
114 | |
115 | #define max(a, b) (((a) > (b)) ? (a) : (b)) | |
116 | ||
117 | #define ALLOCATE_BUFFERS(n) \ | |
118 | do { if ((n) >= nbuffers) allocate_buffers (n); } while (0) | |
119 | ||
120 | /* Make sure `buffers' has at least N elements. */ | |
121 | static void | |
122 | allocate_buffers (n) | |
123 | int n; | |
124 | { | |
125 | register int i, orig_nbuffers; | |
126 | ||
127 | orig_nbuffers = nbuffers; | |
128 | nbuffers = n + 20; | |
129 | buffers = (BUFFERED_STREAM **)xrealloc | |
130 | (buffers, nbuffers * sizeof (BUFFERED_STREAM *)); | |
131 | ||
132 | /* Zero out the new buffers. */ | |
133 | for (i = orig_nbuffers; i < nbuffers; i++) | |
134 | buffers[i] = (BUFFERED_STREAM *)NULL; | |
135 | } | |
136 | ||
137 | /* Construct and return a BUFFERED_STREAM corresponding to file descriptor | |
138 | FD, using BUFFER. */ | |
139 | static BUFFERED_STREAM * | |
140 | make_buffered_stream (fd, buffer, bufsize) | |
141 | int fd; | |
142 | char *buffer; | |
143 | int bufsize; | |
144 | { | |
145 | BUFFERED_STREAM *bp; | |
146 | ||
147 | bp = (BUFFERED_STREAM *)xmalloc (sizeof (BUFFERED_STREAM)); | |
148 | ALLOCATE_BUFFERS (fd); | |
149 | buffers[fd] = bp; | |
150 | bp->b_fd = fd; | |
151 | bp->b_buffer = buffer; | |
152 | bp->b_size = bufsize; | |
ccc6cda3 | 153 | bp->b_used = bp->b_inputp = bp->b_flag = 0; |
726f6388 JA |
154 | if (bufsize == 1) |
155 | bp->b_flag |= B_UNBUFF; | |
156 | return (bp); | |
157 | } | |
158 | ||
159 | /* Allocate a new BUFFERED_STREAM, copy BP to it, and return the new copy. */ | |
160 | static BUFFERED_STREAM * | |
161 | copy_buffered_stream (bp) | |
162 | BUFFERED_STREAM *bp; | |
163 | { | |
164 | BUFFERED_STREAM *nbp; | |
165 | ||
166 | if (!bp) | |
167 | return ((BUFFERED_STREAM *)NULL); | |
168 | ||
169 | nbp = (BUFFERED_STREAM *)xmalloc (sizeof (BUFFERED_STREAM)); | |
170 | xbcopy ((char *)bp, (char *)nbp, sizeof (BUFFERED_STREAM)); | |
171 | return (nbp); | |
172 | } | |
173 | ||
174 | /* Check that file descriptor FD is not the one that bash is currently | |
175 | using to read input from a script. FD is about to be duplicated onto, | |
176 | which means that the kernel will close it for us. If FD is the bash | |
177 | input file descriptor, we need to seek backwards in the script (if | |
178 | possible and necessary -- scripts read from stdin are still unbuffered), | |
179 | allocate a new file descriptor to use for bash input, and re-initialize | |
180 | the buffered stream. */ | |
181 | int | |
182 | check_bash_input (fd) | |
183 | int fd; | |
184 | { | |
185 | int nfd; | |
186 | ||
187 | if (fd > 0 && ((bash_input.type == st_bstream && bash_input.location.buffered_fd == fd) || | |
188 | (interactive_shell == 0 && default_buffered_input == fd))) | |
189 | { | |
190 | /* Sync the stream so we can re-read from the new file descriptor. We | |
191 | might be able to avoid this by copying the buffered stream verbatim | |
192 | to the new file descriptor. */ | |
193 | if (buffers[fd]) | |
194 | sync_buffered_stream (fd); | |
195 | ||
196 | /* Now take care of duplicating the file descriptor that bash is | |
197 | using for input, so we can reinitialize it later. */ | |
198 | nfd = fcntl (fd, F_DUPFD, 10); | |
199 | if (nfd == -1) | |
200 | { | |
201 | if (fcntl (fd, F_GETFD, 0) == 0) | |
ccc6cda3 | 202 | sys_error ("cannot allocate new file descriptor for bash input from fd %d", fd); |
726f6388 JA |
203 | return -1; |
204 | } | |
205 | ||
206 | if (buffers[nfd]) | |
207 | { | |
208 | /* What's this? A stray buffer without an associated open file | |
209 | descriptor? Free up the buffer and report the error. */ | |
ccc6cda3 | 210 | internal_error ("check_bash_input: buffer already exists for new fd %d", nfd); |
726f6388 JA |
211 | free_buffered_stream (buffers[nfd]); |
212 | } | |
213 | ||
214 | /* Reinitialize bash_input.location. */ | |
215 | if (bash_input.type == st_bstream) | |
216 | { | |
217 | bash_input.location.buffered_fd = nfd; | |
218 | fd_to_buffered_stream (nfd); | |
219 | close_buffered_fd (fd); /* XXX */ | |
220 | } | |
221 | else | |
222 | /* If the current input type is not a buffered stream, but the shell | |
223 | is not interactive and therefore using a buffered stream to read | |
224 | input (e.g. with an `eval exec 3>output' inside a script), note | |
225 | that the input fd has been changed. pop_stream() looks at this | |
226 | value and adjusts the input fd to the new value of | |
227 | default_buffered_input accordingly. */ | |
228 | bash_input_fd_changed++; | |
229 | ||
230 | if (default_buffered_input == fd) | |
231 | default_buffered_input = nfd; | |
232 | } | |
233 | return 0; | |
234 | } | |
235 | ||
236 | /* This is the buffered stream analogue of dup2(fd1, fd2). The | |
237 | BUFFERED_STREAM corresponding to fd2 is deallocated, if one exists. | |
238 | BUFFERS[fd1] is copied to BUFFERS[fd2]. This is called by the | |
239 | redirect code for constructs like 4<&0 and 3</etc/rc.local. */ | |
ccc6cda3 | 240 | int |
726f6388 JA |
241 | duplicate_buffered_stream (fd1, fd2) |
242 | int fd1, fd2; | |
243 | { | |
244 | int is_bash_input, m; | |
245 | ||
246 | if (fd1 == fd2) | |
247 | return 0; | |
248 | ||
249 | m = max (fd1, fd2); | |
250 | ALLOCATE_BUFFERS (m); | |
251 | ||
252 | /* If FD2 is the file descriptor bash is currently using for shell input, | |
253 | we need to do some extra work to make sure that the buffered stream | |
254 | actually exists (it might not if fd1 was not active, and the copy | |
255 | didn't actually do anything). */ | |
256 | is_bash_input = (bash_input.type == st_bstream) && | |
257 | (bash_input.location.buffered_fd == fd2); | |
258 | ||
259 | if (buffers[fd2]) | |
260 | free_buffered_stream (buffers[fd2]); | |
261 | buffers[fd2] = copy_buffered_stream (buffers[fd1]); | |
262 | if (buffers[fd2]) | |
263 | buffers[fd2]->b_fd = fd2; | |
264 | ||
ccc6cda3 JA |
265 | if (is_bash_input && !buffers[fd2]) |
266 | fd_to_buffered_stream (fd2); | |
267 | ||
726f6388 JA |
268 | return (fd2); |
269 | } | |
270 | ||
271 | /* Return 1 if a seek on FD will succeed. */ | |
272 | #define fd_is_seekable(fd) (lseek ((fd), 0L, SEEK_CUR) >= 0) | |
273 | ||
274 | /* Take FD, a file descriptor, and create and return a buffered stream | |
275 | corresponding to it. If something is wrong and the file descriptor | |
276 | is invalid, return a NULL stream. */ | |
277 | BUFFERED_STREAM * | |
278 | fd_to_buffered_stream (fd) | |
279 | int fd; | |
280 | { | |
281 | char *buffer; | |
282 | int size; | |
283 | struct stat sb; | |
284 | ||
285 | if (fstat (fd, &sb) < 0) | |
286 | { | |
287 | close (fd); | |
288 | return ((BUFFERED_STREAM *)NULL); | |
289 | } | |
290 | ||
291 | if (fd_is_seekable (fd) == 0) | |
292 | size = 1; | |
293 | else | |
294 | size = (sb.st_size > MAX_INPUT_BUFFER_SIZE) ? MAX_INPUT_BUFFER_SIZE | |
295 | : sb.st_size; | |
296 | ||
297 | buffer = (char *)xmalloc (size); | |
298 | ||
299 | return (make_buffered_stream (fd, buffer, size)); | |
300 | } | |
301 | ||
302 | /* Return a buffered stream corresponding to FILE, a file name. */ | |
303 | BUFFERED_STREAM * | |
304 | open_buffered_stream (file) | |
305 | char *file; | |
306 | { | |
307 | int fd; | |
308 | ||
309 | fd = open (file, O_RDONLY); | |
ccc6cda3 | 310 | return ((fd >= 0) ? fd_to_buffered_stream (fd) : (BUFFERED_STREAM *)NULL); |
726f6388 JA |
311 | } |
312 | ||
313 | /* Deallocate a buffered stream and free up its resources. Make sure we | |
314 | zero out the slot in BUFFERS that points to BP. */ | |
315 | void | |
316 | free_buffered_stream (bp) | |
317 | BUFFERED_STREAM *bp; | |
318 | { | |
319 | int n; | |
320 | ||
321 | if (!bp) | |
322 | return; | |
323 | ||
324 | n = bp->b_fd; | |
325 | if (bp->b_buffer) | |
326 | free (bp->b_buffer); | |
327 | free (bp); | |
328 | buffers[n] = (BUFFERED_STREAM *)NULL; | |
329 | } | |
330 | ||
331 | /* Close the file descriptor associated with BP, a buffered stream, and free | |
332 | up the stream. Return the status of closing BP's file descriptor. */ | |
333 | int | |
334 | close_buffered_stream (bp) | |
335 | BUFFERED_STREAM *bp; | |
336 | { | |
337 | int fd; | |
338 | ||
339 | if (!bp) | |
340 | return (0); | |
341 | fd = bp->b_fd; | |
342 | free_buffered_stream (bp); | |
343 | return (close (fd)); | |
344 | } | |
345 | ||
346 | /* Deallocate the buffered stream associated with file descriptor FD, and | |
347 | close FD. Return the status of the close on FD. */ | |
348 | int | |
349 | close_buffered_fd (fd) | |
350 | int fd; | |
351 | { | |
352 | if (fd >= nbuffers || !buffers || !buffers[fd]) | |
353 | return (close (fd)); | |
354 | return (close_buffered_stream (buffers[fd])); | |
355 | } | |
356 | ||
357 | /* Read a buffer full of characters from BP, a buffered stream. */ | |
358 | static int | |
359 | b_fill_buffer (bp) | |
360 | BUFFERED_STREAM *bp; | |
361 | { | |
362 | do | |
363 | { | |
364 | bp->b_used = read (bp->b_fd, bp->b_buffer, bp->b_size); | |
365 | } | |
366 | while (bp->b_used < 0 && errno == EINTR); | |
367 | if (bp->b_used <= 0) | |
368 | { | |
369 | bp->b_buffer[0] = 0; | |
370 | if (bp->b_used == 0) | |
371 | bp->b_flag |= B_EOF; | |
372 | else | |
373 | bp->b_flag |= B_ERROR; | |
374 | return (EOF); | |
375 | } | |
376 | bp->b_inputp = 0; | |
377 | return (bp->b_buffer[bp->b_inputp++] & 0xFF); | |
378 | } | |
379 | ||
380 | /* Get a character from buffered stream BP. */ | |
381 | #define bufstream_getc(bp) \ | |
382 | (bp->b_inputp == bp->b_used || !bp->b_used) \ | |
383 | ? b_fill_buffer (bp) \ | |
384 | : bp->b_buffer[bp->b_inputp++] & 0xFF | |
385 | ||
386 | /* Push C back onto buffered stream BP. */ | |
387 | static int | |
388 | bufstream_ungetc(c, bp) | |
389 | int c; | |
390 | BUFFERED_STREAM *bp; | |
391 | { | |
392 | if (c == EOF || bp->b_inputp == 0) | |
393 | return (EOF); | |
394 | ||
395 | bp->b_buffer[--bp->b_inputp] = c; | |
396 | return (c); | |
397 | } | |
398 | ||
399 | /* Seek backwards on file BFD to synchronize what we've read so far | |
400 | with the underlying file pointer. */ | |
401 | int | |
402 | sync_buffered_stream (bfd) | |
403 | int bfd; | |
404 | { | |
405 | BUFFERED_STREAM *bp; | |
ccc6cda3 | 406 | off_t chars_left; |
726f6388 JA |
407 | |
408 | bp = buffers[bfd]; | |
409 | if (!bp) | |
410 | return (-1); | |
411 | chars_left = bp->b_used - bp->b_inputp; | |
412 | if (chars_left) | |
413 | lseek (bp->b_fd, -chars_left, SEEK_CUR); | |
414 | bp->b_used = bp->b_inputp = 0; | |
415 | return (0); | |
416 | } | |
417 | ||
418 | int | |
419 | buffered_getchar () | |
420 | { | |
421 | return (bufstream_getc (buffers[bash_input.location.buffered_fd])); | |
422 | } | |
423 | ||
424 | int | |
425 | buffered_ungetchar (c) | |
426 | int c; | |
427 | { | |
428 | return (bufstream_ungetc (c, buffers[bash_input.location.buffered_fd])); | |
429 | } | |
430 | ||
431 | /* Make input come from file descriptor BFD through a buffered stream. */ | |
432 | void | |
433 | with_input_from_buffered_stream (bfd, name) | |
434 | int bfd; | |
435 | char *name; | |
436 | { | |
437 | INPUT_STREAM location; | |
ccc6cda3 | 438 | BUFFERED_STREAM *bp; |
726f6388 JA |
439 | |
440 | location.buffered_fd = bfd; | |
441 | /* Make sure the buffered stream exists. */ | |
ccc6cda3 JA |
442 | bp = fd_to_buffered_stream (bfd); |
443 | init_yy_io (bp == 0 ? return_EOF : buffered_getchar, | |
444 | buffered_ungetchar, st_bstream, name, location); | |
726f6388 JA |
445 | } |
446 | ||
447 | #if defined (TEST) | |
726f6388 JA |
448 | char * |
449 | xmalloc(s) | |
450 | int s; | |
451 | { | |
452 | return ((char *)malloc (s)); | |
453 | } | |
454 | ||
455 | char * | |
456 | xrealloc(s, size) | |
457 | char *s; | |
458 | int size; | |
459 | { | |
460 | if (!s) | |
461 | return((char *)malloc (size)); | |
462 | else | |
463 | return((char *)realloc (s, size)); | |
464 | } | |
465 | ||
466 | void | |
467 | init_yy_io () | |
468 | { | |
469 | } | |
470 | ||
471 | process(bp) | |
472 | BUFFERED_STREAM *bp; | |
473 | { | |
474 | int c; | |
475 | ||
476 | while ((c = bufstream_getc(bp)) != EOF) | |
477 | putchar(c); | |
478 | } | |
479 | ||
480 | BASH_INPUT bash_input; | |
481 | ||
482 | struct stat dsb; /* can be used from gdb */ | |
483 | ||
484 | /* imitate /bin/cat */ | |
485 | main(argc, argv) | |
486 | int argc; | |
487 | char **argv; | |
488 | { | |
489 | register int i; | |
490 | BUFFERED_STREAM *bp; | |
491 | ||
492 | if (argc == 1) { | |
493 | bp = fd_to_buffered_stream (0); | |
494 | process(bp); | |
495 | exit(0); | |
496 | } | |
497 | for (i = 1; i < argc; i++) { | |
498 | if (argv[i][0] == '-' && argv[i][1] == '\0') { | |
499 | bp = fd_to_buffered_stream (0); | |
500 | if (!bp) | |
501 | continue; | |
502 | process(bp); | |
503 | free_buffered_stream (bp); | |
504 | } else { | |
505 | bp = open_buffered_stream (argv[i]); | |
506 | if (!bp) | |
507 | continue; | |
508 | process(bp); | |
509 | close_buffered_stream (bp); | |
510 | } | |
511 | } | |
512 | exit(0); | |
513 | } | |
ccc6cda3 JA |
514 | #endif /* TEST */ |
515 | #endif /* BUFFERED_INPUT */ |