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4ee9c684 | 1 | /* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. |
2 | Contributed by Andy Vaught | |
3 | ||
4 | This file is part of the GNU Fortran 95 runtime library (libgfortran). | |
5 | ||
6 | Libgfortran is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | Libgfortran is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with Libgfortran; see the file COPYING. If not, write to | |
18 | the Free Software Foundation, 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
21 | /* Unix stream I/O module */ | |
22 | ||
23 | #include "config.h" | |
24 | #include <stdlib.h> | |
25 | #include <limits.h> | |
26 | ||
27 | #include <unistd.h> | |
91e6f54a | 28 | #include <stdio.h> |
4ee9c684 | 29 | #include <sys/stat.h> |
30 | #include <fcntl.h> | |
31 | ||
d2455565 | 32 | #ifdef HAVE_SYS_MMAN_H |
4ee9c684 | 33 | #include <sys/mman.h> |
d2455565 | 34 | #endif |
4ee9c684 | 35 | #include <string.h> |
36 | #include <errno.h> | |
37 | ||
38 | #include "libgfortran.h" | |
39 | #include "io.h" | |
40 | ||
41 | #ifndef PATH_MAX | |
42 | #define PATH_MAX 1024 | |
43 | #endif | |
44 | ||
45 | #ifndef MAP_FAILED | |
46 | #define MAP_FAILED ((void *) -1) | |
47 | #endif | |
48 | ||
d2455565 | 49 | #ifndef PROT_READ |
50 | #define PROT_READ 1 | |
51 | #endif | |
52 | ||
53 | #ifndef PROT_WRITE | |
54 | #define PROT_WRITE 2 | |
55 | #endif | |
56 | ||
7dfba97b | 57 | /* These flags aren't defined on all targets (mingw32), so provide them |
58 | here. */ | |
59 | #ifndef S_IRGRP | |
60 | #define S_IRGRP 0 | |
61 | #endif | |
62 | ||
63 | #ifndef S_IWGRP | |
64 | #define S_IWGRP 0 | |
65 | #endif | |
66 | ||
67 | #ifndef S_IROTH | |
68 | #define S_IROTH 0 | |
69 | #endif | |
70 | ||
71 | #ifndef S_IWOTH | |
72 | #define S_IWOTH 0 | |
73 | #endif | |
74 | ||
4ee9c684 | 75 | /* This implementation of stream I/O is based on the paper: |
76 | * | |
77 | * "Exploiting the advantages of mapped files for stream I/O", | |
78 | * O. Krieger, M. Stumm and R. Umrau, "Proceedings of the 1992 Winter | |
79 | * USENIX conference", p. 27-42. | |
80 | * | |
81 | * It differs in a number of ways from the version described in the | |
82 | * paper. First of all, threads are not an issue during I/O and we | |
83 | * also don't have to worry about having multiple regions, since | |
84 | * fortran's I/O model only allows you to be one place at a time. | |
85 | * | |
86 | * On the other hand, we have to be able to writing at the end of a | |
87 | * stream, read from the start of a stream or read and write blocks of | |
88 | * bytes from an arbitrary position. After opening a file, a pointer | |
89 | * to a stream structure is returned, which is used to handle file | |
90 | * accesses until the file is closed. | |
91 | * | |
92 | * salloc_at_r(stream, len, where)-- Given a stream pointer, return a | |
93 | * pointer to a block of memory that mirror the file at position | |
94 | * 'where' that is 'len' bytes long. The len integer is updated to | |
95 | * reflect how many bytes were actually read. The only reason for a | |
96 | * short read is end of file. The file pointer is updated. The | |
97 | * pointer is valid until the next call to salloc_*. | |
98 | * | |
99 | * salloc_at_w(stream, len, where)-- Given the stream pointer, returns | |
100 | * a pointer to a block of memory that is updated to reflect the state | |
101 | * of the file. The length of the buffer is always equal to that | |
102 | * requested. The buffer must be completely set by the caller. When | |
103 | * data has been written, the sfree() function must be called to | |
104 | * indicate that the caller is done writing data to the buffer. This | |
105 | * may or may not cause a physical write. | |
106 | * | |
107 | * Short forms of these are salloc_r() and salloc_w() which drop the | |
108 | * 'where' parameter and use the current file pointer. */ | |
109 | ||
110 | ||
111 | #define BUFFER_SIZE 8192 | |
112 | ||
113 | typedef struct | |
114 | { | |
115 | stream st; | |
116 | ||
117 | int fd; | |
b093181d | 118 | gfc_offset buffer_offset; /* File offset of the start of the buffer */ |
119 | gfc_offset physical_offset; /* Current physical file offset */ | |
120 | gfc_offset logical_offset; /* Current logical file offset */ | |
121 | gfc_offset dirty_offset; /* Start of modified bytes in buffer */ | |
5a78b88f | 122 | gfc_offset file_length; /* Length of the file, -1 if not seekable. */ |
4ee9c684 | 123 | |
124 | char *buffer; | |
125 | int len; /* Physical length of the current buffer */ | |
126 | int active; /* Length of valid bytes in the buffer */ | |
127 | ||
128 | int prot; | |
129 | int ndirty; /* Dirty bytes starting at dirty_offset */ | |
130 | ||
131 | unsigned unbuffered:1, mmaped:1; | |
132 | ||
133 | char small_buffer[BUFFER_SIZE]; | |
134 | ||
135 | } | |
136 | unix_stream; | |
137 | ||
138 | /*move_pos_offset()-- Move the record pointer right or left | |
139 | *relative to current position */ | |
140 | ||
141 | int | |
142 | move_pos_offset (stream* st, int pos_off) | |
143 | { | |
144 | unix_stream * str = (unix_stream*)st; | |
145 | if (pos_off < 0) | |
146 | { | |
147 | str->active += pos_off; | |
148 | if (str->active < 0) | |
149 | str->active = 0; | |
150 | ||
151 | str->logical_offset += pos_off; | |
152 | ||
153 | if (str->dirty_offset+str->ndirty > str->logical_offset) | |
154 | { | |
155 | if (str->ndirty + pos_off > 0) | |
156 | str->ndirty += pos_off ; | |
157 | else | |
158 | { | |
159 | str->dirty_offset += pos_off + pos_off; | |
160 | str->ndirty = 0 ; | |
161 | } | |
162 | } | |
163 | ||
164 | return pos_off ; | |
165 | } | |
166 | return 0 ; | |
167 | } | |
168 | ||
169 | ||
170 | /* fix_fd()-- Given a file descriptor, make sure it is not one of the | |
171 | * standard descriptors, returning a non-standard descriptor. If the | |
172 | * user specifies that system errors should go to standard output, | |
173 | * then closes standard output, we don't want the system errors to a | |
174 | * file that has been given file descriptor 1 or 0. We want to send | |
175 | * the error to the invalid descriptor. */ | |
176 | ||
177 | static int | |
178 | fix_fd (int fd) | |
179 | { | |
180 | int input, output, error; | |
181 | ||
182 | input = output = error = 0; | |
183 | ||
184 | /* Unix allocates the lowest descriptors first, so a loop is not | |
185 | * required, but this order is. */ | |
186 | ||
187 | if (fd == STDIN_FILENO) | |
188 | { | |
189 | fd = dup (fd); | |
190 | input = 1; | |
191 | } | |
192 | if (fd == STDOUT_FILENO) | |
193 | { | |
194 | fd = dup (fd); | |
195 | output = 1; | |
196 | } | |
197 | if (fd == STDERR_FILENO) | |
198 | { | |
199 | fd = dup (fd); | |
200 | error = 1; | |
201 | } | |
202 | ||
203 | if (input) | |
204 | close (STDIN_FILENO); | |
205 | if (output) | |
206 | close (STDOUT_FILENO); | |
207 | if (error) | |
208 | close (STDERR_FILENO); | |
209 | ||
210 | return fd; | |
211 | } | |
212 | ||
213 | ||
214 | /* write()-- Write a buffer to a descriptor, allowing for short writes */ | |
215 | ||
216 | static int | |
217 | writen (int fd, char *buffer, int len) | |
218 | { | |
219 | int n, n0; | |
220 | ||
221 | n0 = len; | |
222 | ||
223 | while (len > 0) | |
224 | { | |
225 | n = write (fd, buffer, len); | |
226 | if (n < 0) | |
227 | return n; | |
228 | ||
229 | buffer += n; | |
230 | len -= n; | |
231 | } | |
232 | ||
233 | return n0; | |
234 | } | |
235 | ||
236 | ||
237 | #if 0 | |
238 | /* readn()-- Read bytes into a buffer, allowing for short reads. If | |
239 | * fewer than len bytes are returned, it is because we've hit the end | |
240 | * of file. */ | |
241 | ||
242 | static int | |
243 | readn (int fd, char *buffer, int len) | |
244 | { | |
245 | int nread, n; | |
246 | ||
247 | nread = 0; | |
248 | ||
249 | while (len > 0) | |
250 | { | |
251 | n = read (fd, buffer, len); | |
252 | if (n < 0) | |
253 | return n; | |
254 | ||
255 | if (n == 0) | |
256 | return nread; | |
257 | ||
258 | buffer += n; | |
259 | nread += n; | |
260 | len -= n; | |
261 | } | |
262 | ||
263 | return nread; | |
264 | } | |
265 | #endif | |
266 | ||
267 | ||
268 | /* get_oserror()-- Get the most recent operating system error. For | |
269 | * unix, this is errno. */ | |
270 | ||
271 | const char * | |
272 | get_oserror (void) | |
273 | { | |
274 | ||
275 | return strerror (errno); | |
276 | } | |
277 | ||
278 | ||
279 | /* sys_exit()-- Terminate the program with an exit code */ | |
280 | ||
281 | void | |
282 | sys_exit (int code) | |
283 | { | |
284 | ||
285 | exit (code); | |
286 | } | |
287 | ||
288 | ||
4ee9c684 | 289 | /********************************************************************* |
290 | File descriptor stream functions | |
291 | *********************************************************************/ | |
292 | ||
293 | /* fd_flush()-- Write bytes that need to be written */ | |
294 | ||
295 | static try | |
296 | fd_flush (unix_stream * s) | |
297 | { | |
298 | ||
299 | if (s->ndirty == 0) | |
300 | return SUCCESS;; | |
301 | ||
302 | if (s->physical_offset != s->dirty_offset && | |
303 | lseek (s->fd, s->dirty_offset, SEEK_SET) < 0) | |
304 | return FAILURE; | |
305 | ||
306 | if (writen (s->fd, s->buffer + (s->dirty_offset - s->buffer_offset), | |
307 | s->ndirty) < 0) | |
308 | return FAILURE; | |
309 | ||
310 | s->physical_offset = s->dirty_offset + s->ndirty; | |
5a78b88f | 311 | |
312 | /* don't increment file_length if the file is non-seekable */ | |
313 | if (s->file_length != -1 && s->physical_offset > s->file_length) | |
4ee9c684 | 314 | s->file_length = s->physical_offset; |
315 | s->ndirty = 0; | |
316 | ||
317 | return SUCCESS; | |
318 | } | |
319 | ||
320 | ||
321 | /* fd_alloc()-- Arrange a buffer such that the salloc() request can be | |
322 | * satisfied. This subroutine gets the buffer ready for whatever is | |
323 | * to come next. */ | |
324 | ||
325 | static void | |
b093181d | 326 | fd_alloc (unix_stream * s, gfc_offset where, int *len) |
4ee9c684 | 327 | { |
328 | char *new_buffer; | |
329 | int n, read_len; | |
330 | ||
331 | if (*len <= BUFFER_SIZE) | |
332 | { | |
333 | new_buffer = s->small_buffer; | |
334 | read_len = BUFFER_SIZE; | |
335 | } | |
336 | else | |
337 | { | |
338 | new_buffer = get_mem (*len); | |
339 | read_len = *len; | |
340 | } | |
341 | ||
342 | /* Salvage bytes currently within the buffer. This is important for | |
343 | * devices that cannot seek. */ | |
344 | ||
345 | if (s->buffer != NULL && s->buffer_offset <= where && | |
346 | where <= s->buffer_offset + s->active) | |
347 | { | |
348 | ||
349 | n = s->active - (where - s->buffer_offset); | |
350 | memmove (new_buffer, s->buffer + (where - s->buffer_offset), n); | |
351 | ||
352 | s->active = n; | |
353 | } | |
354 | else | |
355 | { /* new buffer starts off empty */ | |
356 | s->active = 0; | |
357 | } | |
358 | ||
359 | s->buffer_offset = where; | |
360 | ||
361 | /* free the old buffer if necessary */ | |
362 | ||
363 | if (s->buffer != NULL && s->buffer != s->small_buffer) | |
364 | free_mem (s->buffer); | |
365 | ||
366 | s->buffer = new_buffer; | |
367 | s->len = read_len; | |
368 | s->mmaped = 0; | |
369 | } | |
370 | ||
371 | ||
372 | /* fd_alloc_r_at()-- Allocate a stream buffer for reading. Either | |
373 | * we've already buffered the data or we need to load it. Returns | |
374 | * NULL on I/O error. */ | |
375 | ||
376 | static char * | |
b093181d | 377 | fd_alloc_r_at (unix_stream * s, int *len, gfc_offset where) |
4ee9c684 | 378 | { |
b093181d | 379 | gfc_offset m; |
4ee9c684 | 380 | int n; |
381 | ||
382 | if (where == -1) | |
383 | where = s->logical_offset; | |
384 | ||
385 | if (s->buffer != NULL && s->buffer_offset <= where && | |
386 | where + *len <= s->buffer_offset + s->active) | |
387 | { | |
388 | ||
389 | /* Return a position within the current buffer */ | |
390 | ||
391 | s->logical_offset = where + *len; | |
392 | return s->buffer + where - s->buffer_offset; | |
393 | } | |
394 | ||
395 | fd_alloc (s, where, len); | |
396 | ||
397 | m = where + s->active; | |
398 | ||
399 | if (s->physical_offset != m && lseek (s->fd, m, SEEK_SET) < 0) | |
400 | return NULL; | |
401 | ||
402 | n = read (s->fd, s->buffer + s->active, s->len - s->active); | |
403 | if (n < 0) | |
404 | return NULL; | |
405 | ||
406 | s->physical_offset = where + n; | |
407 | ||
408 | s->active += n; | |
409 | if (s->active < *len) | |
410 | *len = s->active; /* Bytes actually available */ | |
411 | ||
412 | s->logical_offset = where + *len; | |
413 | ||
414 | return s->buffer; | |
415 | } | |
416 | ||
417 | ||
418 | /* fd_alloc_w_at()-- Allocate a stream buffer for writing. Either | |
419 | * we've already buffered the data or we need to load it. */ | |
420 | ||
421 | static char * | |
b093181d | 422 | fd_alloc_w_at (unix_stream * s, int *len, gfc_offset where) |
4ee9c684 | 423 | { |
b093181d | 424 | gfc_offset n; |
4ee9c684 | 425 | |
426 | if (where == -1) | |
427 | where = s->logical_offset; | |
428 | ||
429 | if (s->buffer == NULL || s->buffer_offset > where || | |
430 | where + *len > s->buffer_offset + s->len) | |
431 | { | |
432 | ||
433 | if (fd_flush (s) == FAILURE) | |
434 | return NULL; | |
435 | fd_alloc (s, where, len); | |
436 | } | |
437 | ||
438 | /* Return a position within the current buffer */ | |
5a78b88f | 439 | if (s->ndirty == 0 |
440 | || where > s->dirty_offset + s->ndirty | |
441 | || s->dirty_offset > where + *len) | |
442 | { /* Discontiguous blocks, start with a clean buffer. */ | |
443 | /* Flush the buffer. */ | |
444 | if (s->ndirty != 0) | |
445 | fd_flush (s); | |
446 | s->dirty_offset = where; | |
447 | s->ndirty = *len; | |
4ee9c684 | 448 | } |
449 | else | |
5a78b88f | 450 | { |
451 | gfc_offset start; /* Merge with the existing data. */ | |
452 | if (where < s->dirty_offset) | |
453 | start = where; | |
454 | else | |
455 | start = s->dirty_offset; | |
456 | if (where + *len > s->dirty_offset + s->ndirty) | |
457 | s->ndirty = where + *len - start; | |
458 | else | |
459 | s->ndirty = s->dirty_offset + s->ndirty - start; | |
460 | s->dirty_offset = start; | |
4ee9c684 | 461 | } |
462 | ||
463 | s->logical_offset = where + *len; | |
464 | ||
f82543e7 | 465 | if (where + *len > s->file_length) |
466 | s->file_length = where + *len; | |
467 | ||
4ee9c684 | 468 | n = s->logical_offset - s->buffer_offset; |
469 | if (n > s->active) | |
470 | s->active = n; | |
471 | ||
472 | return s->buffer + where - s->buffer_offset; | |
473 | } | |
474 | ||
475 | ||
476 | static try | |
477 | fd_sfree (unix_stream * s) | |
478 | { | |
479 | ||
480 | if (s->ndirty != 0 && | |
481 | (s->buffer != s->small_buffer || options.all_unbuffered || | |
482 | s->unbuffered)) | |
483 | return fd_flush (s); | |
484 | ||
485 | return SUCCESS; | |
486 | } | |
487 | ||
488 | ||
489 | static int | |
b093181d | 490 | fd_seek (unix_stream * s, gfc_offset offset) |
4ee9c684 | 491 | { |
492 | ||
493 | s->physical_offset = s->logical_offset = offset; | |
494 | ||
495 | return (lseek (s->fd, offset, SEEK_SET) < 0) ? FAILURE : SUCCESS; | |
496 | } | |
497 | ||
498 | ||
499 | /* truncate_file()-- Given a unit, truncate the file at the current | |
500 | * position. Sets the physical location to the new end of the file. | |
501 | * Returns nonzero on error. */ | |
502 | ||
503 | static try | |
504 | fd_truncate (unix_stream * s) | |
505 | { | |
506 | ||
5a78b88f | 507 | if (lseek (s->fd, s->logical_offset, SEEK_SET) == -1) |
4ee9c684 | 508 | return FAILURE; |
509 | ||
5a78b88f | 510 | /* non-seekable files, like terminals and fifo's fail the lseek. |
511 | the fd is a regular file at this point */ | |
4ee9c684 | 512 | |
5a78b88f | 513 | if (ftruncate (s->fd, s->logical_offset)) |
514 | { | |
4ee9c684 | 515 | return FAILURE; |
5a78b88f | 516 | } |
517 | ||
518 | s->physical_offset = s->file_length = s->logical_offset; | |
4ee9c684 | 519 | |
520 | return SUCCESS; | |
521 | } | |
522 | ||
523 | ||
524 | static try | |
525 | fd_close (unix_stream * s) | |
526 | { | |
527 | ||
528 | if (fd_flush (s) == FAILURE) | |
529 | return FAILURE; | |
530 | ||
531 | if (s->buffer != NULL && s->buffer != s->small_buffer) | |
532 | free_mem (s->buffer); | |
533 | ||
534 | if (close (s->fd) < 0) | |
535 | return FAILURE; | |
536 | ||
537 | free_mem (s); | |
538 | ||
539 | return SUCCESS; | |
540 | } | |
541 | ||
542 | ||
543 | static void | |
544 | fd_open (unix_stream * s) | |
545 | { | |
546 | ||
547 | if (isatty (s->fd)) | |
548 | s->unbuffered = 1; | |
549 | ||
550 | s->st.alloc_r_at = (void *) fd_alloc_r_at; | |
551 | s->st.alloc_w_at = (void *) fd_alloc_w_at; | |
552 | s->st.sfree = (void *) fd_sfree; | |
553 | s->st.close = (void *) fd_close; | |
554 | s->st.seek = (void *) fd_seek; | |
555 | s->st.truncate = (void *) fd_truncate; | |
556 | ||
557 | s->buffer = NULL; | |
558 | } | |
559 | ||
560 | ||
561 | /********************************************************************* | |
562 | mmap stream functions | |
563 | ||
564 | Because mmap() is not capable of extending a file, we have to keep | |
565 | track of how long the file is. We also have to be able to detect end | |
566 | of file conditions. If there are multiple writers to the file (which | |
567 | can only happen outside the current program), things will get | |
568 | confused. Then again, things will get confused anyway. | |
569 | ||
570 | *********************************************************************/ | |
571 | ||
572 | #if HAVE_MMAP | |
573 | ||
574 | static int page_size, page_mask; | |
575 | ||
576 | /* mmap_flush()-- Deletes a memory mapping if something is mapped. */ | |
577 | ||
578 | static try | |
579 | mmap_flush (unix_stream * s) | |
580 | { | |
581 | ||
582 | if (!s->mmaped) | |
583 | return fd_flush (s); | |
584 | ||
585 | if (s->buffer == NULL) | |
586 | return SUCCESS; | |
587 | ||
588 | if (munmap (s->buffer, s->active)) | |
589 | return FAILURE; | |
590 | ||
591 | s->buffer = NULL; | |
592 | s->active = 0; | |
593 | ||
594 | return SUCCESS; | |
595 | } | |
596 | ||
597 | ||
598 | /* mmap_alloc()-- mmap() a section of the file. The whole section is | |
599 | * guaranteed to be mappable. */ | |
600 | ||
601 | static try | |
b093181d | 602 | mmap_alloc (unix_stream * s, gfc_offset where, int *len) |
4ee9c684 | 603 | { |
b093181d | 604 | gfc_offset offset; |
4ee9c684 | 605 | int length; |
606 | char *p; | |
607 | ||
608 | if (mmap_flush (s) == FAILURE) | |
609 | return FAILURE; | |
610 | ||
611 | offset = where & page_mask; /* Round down to the next page */ | |
612 | ||
613 | length = ((where - offset) & page_mask) + 2 * page_size; | |
614 | ||
615 | p = mmap (NULL, length, s->prot, MAP_SHARED, s->fd, offset); | |
616 | if (p == (char *) MAP_FAILED) | |
617 | return FAILURE; | |
618 | ||
619 | s->mmaped = 1; | |
620 | s->buffer = p; | |
621 | s->buffer_offset = offset; | |
622 | s->active = length; | |
623 | ||
624 | return SUCCESS; | |
625 | } | |
626 | ||
627 | ||
628 | static char * | |
b093181d | 629 | mmap_alloc_r_at (unix_stream * s, int *len, gfc_offset where) |
4ee9c684 | 630 | { |
b093181d | 631 | gfc_offset m; |
4ee9c684 | 632 | |
633 | if (where == -1) | |
634 | where = s->logical_offset; | |
635 | ||
636 | m = where + *len; | |
637 | ||
638 | if ((s->buffer == NULL || s->buffer_offset > where || | |
639 | m > s->buffer_offset + s->active) && | |
640 | mmap_alloc (s, where, len) == FAILURE) | |
641 | return NULL; | |
642 | ||
643 | if (m > s->file_length) | |
644 | { | |
645 | *len = s->file_length - s->logical_offset; | |
646 | s->logical_offset = s->file_length; | |
647 | } | |
648 | else | |
649 | s->logical_offset = m; | |
650 | ||
651 | return s->buffer + (where - s->buffer_offset); | |
652 | } | |
653 | ||
654 | ||
655 | static char * | |
b093181d | 656 | mmap_alloc_w_at (unix_stream * s, int *len, gfc_offset where) |
4ee9c684 | 657 | { |
658 | if (where == -1) | |
659 | where = s->logical_offset; | |
660 | ||
661 | /* If we're extending the file, we have to use file descriptor | |
662 | * methods. */ | |
663 | ||
664 | if (where + *len > s->file_length) | |
665 | { | |
666 | if (s->mmaped) | |
667 | mmap_flush (s); | |
668 | return fd_alloc_w_at (s, len, where); | |
669 | } | |
670 | ||
671 | if ((s->buffer == NULL || s->buffer_offset > where || | |
8ff470b4 | 672 | where + *len > s->buffer_offset + s->active || |
673 | where < s->buffer_offset + s->active) && | |
4ee9c684 | 674 | mmap_alloc (s, where, len) == FAILURE) |
675 | return NULL; | |
676 | ||
677 | s->logical_offset = where + *len; | |
678 | ||
679 | return s->buffer + where - s->buffer_offset; | |
680 | } | |
681 | ||
682 | ||
683 | static int | |
b093181d | 684 | mmap_seek (unix_stream * s, gfc_offset offset) |
4ee9c684 | 685 | { |
686 | ||
687 | s->logical_offset = offset; | |
688 | return SUCCESS; | |
689 | } | |
690 | ||
691 | ||
692 | static try | |
693 | mmap_close (unix_stream * s) | |
694 | { | |
695 | try t; | |
696 | ||
697 | t = mmap_flush (s); | |
698 | ||
699 | if (close (s->fd) < 0) | |
700 | t = FAILURE; | |
701 | free_mem (s); | |
702 | ||
703 | return t; | |
704 | } | |
705 | ||
706 | ||
707 | static try | |
708 | mmap_sfree (unix_stream * s) | |
709 | { | |
710 | ||
711 | return SUCCESS; | |
712 | } | |
713 | ||
714 | ||
715 | /* mmap_open()-- mmap_specific open. If the particular file cannot be | |
716 | * mmap()-ed, we fall back to the file descriptor functions. */ | |
717 | ||
718 | static try | |
719 | mmap_open (unix_stream * s) | |
720 | { | |
721 | char *p; | |
722 | int i; | |
723 | ||
724 | page_size = getpagesize (); | |
725 | page_mask = ~0; | |
726 | ||
727 | p = mmap (0, page_size, s->prot, MAP_SHARED, s->fd, 0); | |
728 | if (p == (char *) MAP_FAILED) | |
729 | { | |
730 | fd_open (s); | |
731 | return SUCCESS; | |
732 | } | |
733 | ||
734 | munmap (p, page_size); | |
735 | ||
736 | i = page_size >> 1; | |
737 | while (i != 0) | |
738 | { | |
739 | page_mask <<= 1; | |
740 | i >>= 1; | |
741 | } | |
742 | ||
743 | s->st.alloc_r_at = (void *) mmap_alloc_r_at; | |
744 | s->st.alloc_w_at = (void *) mmap_alloc_w_at; | |
745 | s->st.sfree = (void *) mmap_sfree; | |
746 | s->st.close = (void *) mmap_close; | |
747 | s->st.seek = (void *) mmap_seek; | |
748 | s->st.truncate = (void *) fd_truncate; | |
749 | ||
750 | if (lseek (s->fd, s->file_length, SEEK_SET) < 0) | |
751 | return FAILURE; | |
752 | ||
753 | return SUCCESS; | |
754 | } | |
755 | ||
756 | #endif | |
757 | ||
758 | ||
759 | /********************************************************************* | |
760 | memory stream functions - These are used for internal files | |
761 | ||
762 | The idea here is that a single stream structure is created and all | |
763 | requests must be satisfied from it. The location and size of the | |
764 | buffer is the character variable supplied to the READ or WRITE | |
765 | statement. | |
766 | ||
767 | *********************************************************************/ | |
768 | ||
769 | ||
770 | static char * | |
b093181d | 771 | mem_alloc_r_at (unix_stream * s, int *len, gfc_offset where) |
4ee9c684 | 772 | { |
b093181d | 773 | gfc_offset n; |
4ee9c684 | 774 | |
775 | if (where == -1) | |
776 | where = s->logical_offset; | |
777 | ||
778 | if (where < s->buffer_offset || where > s->buffer_offset + s->active) | |
779 | return NULL; | |
780 | ||
4ee9c684 | 781 | s->logical_offset = where + *len; |
782 | ||
11de4bf9 | 783 | n = s->buffer_offset + s->active - where; |
4ee9c684 | 784 | if (*len > n) |
785 | *len = n; | |
786 | ||
787 | return s->buffer + (where - s->buffer_offset); | |
788 | } | |
789 | ||
790 | ||
791 | static char * | |
b093181d | 792 | mem_alloc_w_at (unix_stream * s, int *len, gfc_offset where) |
4ee9c684 | 793 | { |
b093181d | 794 | gfc_offset m; |
4ee9c684 | 795 | |
796 | if (where == -1) | |
797 | where = s->logical_offset; | |
798 | ||
799 | m = where + *len; | |
800 | ||
801 | if (where < s->buffer_offset || m > s->buffer_offset + s->active) | |
802 | return NULL; | |
803 | ||
804 | s->logical_offset = m; | |
805 | ||
806 | return s->buffer + (where - s->buffer_offset); | |
807 | } | |
808 | ||
809 | ||
810 | static int | |
b093181d | 811 | mem_seek (unix_stream * s, gfc_offset offset) |
4ee9c684 | 812 | { |
813 | ||
814 | if (offset > s->file_length) | |
815 | { | |
816 | errno = ESPIPE; | |
817 | return FAILURE; | |
818 | } | |
819 | ||
820 | s->logical_offset = offset; | |
821 | return SUCCESS; | |
822 | } | |
823 | ||
824 | ||
825 | static int | |
826 | mem_truncate (unix_stream * s) | |
827 | { | |
828 | ||
829 | return SUCCESS; | |
830 | } | |
831 | ||
832 | ||
833 | static try | |
834 | mem_close (unix_stream * s) | |
835 | { | |
15fee5a5 | 836 | free_mem (s); |
4ee9c684 | 837 | |
838 | return SUCCESS; | |
839 | } | |
840 | ||
841 | ||
842 | static try | |
843 | mem_sfree (unix_stream * s) | |
844 | { | |
845 | ||
846 | return SUCCESS; | |
847 | } | |
848 | ||
849 | ||
850 | ||
851 | /********************************************************************* | |
852 | Public functions -- A reimplementation of this module needs to | |
853 | define functional equivalents of the following. | |
854 | *********************************************************************/ | |
855 | ||
856 | /* empty_internal_buffer()-- Zero the buffer of Internal file */ | |
857 | ||
858 | void | |
859 | empty_internal_buffer(stream *strm) | |
860 | { | |
861 | unix_stream * s = (unix_stream *) strm; | |
862 | memset(s->buffer, ' ', s->file_length); | |
863 | } | |
864 | ||
865 | /* open_internal()-- Returns a stream structure from an internal file */ | |
866 | ||
867 | stream * | |
868 | open_internal (char *base, int length) | |
869 | { | |
870 | unix_stream *s; | |
871 | ||
872 | s = get_mem (sizeof (unix_stream)); | |
873 | ||
874 | s->buffer = base; | |
875 | s->buffer_offset = 0; | |
876 | ||
877 | s->logical_offset = 0; | |
878 | s->active = s->file_length = length; | |
879 | ||
880 | s->st.alloc_r_at = (void *) mem_alloc_r_at; | |
881 | s->st.alloc_w_at = (void *) mem_alloc_w_at; | |
882 | s->st.sfree = (void *) mem_sfree; | |
883 | s->st.close = (void *) mem_close; | |
884 | s->st.seek = (void *) mem_seek; | |
885 | s->st.truncate = (void *) mem_truncate; | |
886 | ||
887 | return (stream *) s; | |
888 | } | |
889 | ||
890 | ||
891 | /* fd_to_stream()-- Given an open file descriptor, build a stream | |
892 | * around it. */ | |
893 | ||
894 | static stream * | |
895 | fd_to_stream (int fd, int prot) | |
896 | { | |
897 | struct stat statbuf; | |
898 | unix_stream *s; | |
899 | ||
900 | s = get_mem (sizeof (unix_stream)); | |
901 | ||
902 | s->fd = fd; | |
903 | s->buffer_offset = 0; | |
904 | s->physical_offset = 0; | |
905 | s->logical_offset = 0; | |
906 | s->prot = prot; | |
907 | ||
908 | /* Get the current length of the file. */ | |
909 | ||
910 | fstat (fd, &statbuf); | |
911 | s->file_length = S_ISREG (statbuf.st_mode) ? statbuf.st_size : -1; | |
912 | ||
913 | #if HAVE_MMAP | |
914 | mmap_open (s); | |
915 | #else | |
916 | fd_open (s); | |
917 | #endif | |
918 | ||
919 | return (stream *) s; | |
920 | } | |
921 | ||
922 | ||
771c1b50 | 923 | /* Given the Fortran unit number, convert it to a C file descriptor. */ |
924 | ||
925 | int | |
926 | unit_to_fd(int unit) | |
927 | { | |
928 | ||
929 | gfc_unit *us; | |
930 | ||
931 | us = find_unit(unit); | |
932 | if (us == NULL) | |
933 | return -1; | |
934 | ||
935 | return ((unix_stream *) us->s)->fd; | |
936 | } | |
937 | ||
938 | ||
4ee9c684 | 939 | /* unpack_filename()-- Given a fortran string and a pointer to a |
940 | * buffer that is PATH_MAX characters, convert the fortran string to a | |
941 | * C string in the buffer. Returns nonzero if this is not possible. */ | |
942 | ||
943 | static int | |
944 | unpack_filename (char *cstring, const char *fstring, int len) | |
945 | { | |
946 | ||
947 | len = fstrlen (fstring, len); | |
948 | if (len >= PATH_MAX) | |
949 | return 1; | |
950 | ||
951 | memmove (cstring, fstring, len); | |
952 | cstring[len] = '\0'; | |
953 | ||
954 | return 0; | |
955 | } | |
956 | ||
957 | ||
958 | /* tempfile()-- Generate a temporary filename for a scratch file and | |
959 | * open it. mkstemp() opens the file for reading and writing, but the | |
960 | * library mode prevents anything that is not allowed. The descriptor | |
7dfba97b | 961 | * is returned, which is -1 on error. The template is pointed to by |
962 | * ioparm.file, which is copied into the unit structure | |
4ee9c684 | 963 | * and freed later. */ |
964 | ||
965 | static int | |
966 | tempfile (void) | |
967 | { | |
968 | const char *tempdir; | |
969 | char *template; | |
970 | int fd; | |
971 | ||
972 | tempdir = getenv ("GFORTRAN_TMPDIR"); | |
973 | if (tempdir == NULL) | |
974 | tempdir = getenv ("TMP"); | |
975 | if (tempdir == NULL) | |
976 | tempdir = DEFAULT_TEMPDIR; | |
977 | ||
978 | template = get_mem (strlen (tempdir) + 20); | |
979 | ||
7dfba97b | 980 | st_sprintf (template, "%s/gfortrantmpXXXXXX", tempdir); |
981 | ||
982 | #ifdef HAVE_MKSTEMP | |
4ee9c684 | 983 | |
984 | fd = mkstemp (template); | |
985 | ||
7dfba97b | 986 | #else /* HAVE_MKSTEMP */ |
987 | ||
988 | if (mktemp (template)) | |
989 | do | |
990 | fd = open (template, O_CREAT | O_EXCL, S_IREAD | S_IWRITE); | |
991 | while (!(fd == -1 && errno == EEXIST) && mktemp (template)); | |
992 | else | |
993 | fd = -1; | |
994 | ||
995 | #endif /* HAVE_MKSTEMP */ | |
996 | ||
4ee9c684 | 997 | if (fd < 0) |
998 | free_mem (template); | |
999 | else | |
1000 | { | |
1001 | ioparm.file = template; | |
1002 | ioparm.file_len = strlen (template); /* Don't include trailing nul */ | |
1003 | } | |
1004 | ||
1005 | return fd; | |
1006 | } | |
1007 | ||
1008 | ||
1009 | /* regular_file()-- Open a regular file. Returns the descriptor, which is less than zero on error. */ | |
1010 | ||
1011 | static int | |
1012 | regular_file (unit_action action, unit_status status) | |
1013 | { | |
1014 | char path[PATH_MAX + 1]; | |
1015 | struct stat statbuf; | |
1016 | int mode; | |
1017 | ||
1018 | if (unpack_filename (path, ioparm.file, ioparm.file_len)) | |
1019 | { | |
1020 | errno = ENOENT; /* Fake an OS error */ | |
1021 | return -1; | |
1022 | } | |
1023 | ||
1024 | mode = 0; | |
1025 | ||
1026 | switch (action) | |
1027 | { | |
1028 | case ACTION_READ: | |
1029 | mode = O_RDONLY; | |
1030 | break; | |
1031 | ||
1032 | case ACTION_WRITE: | |
1033 | mode = O_WRONLY; | |
1034 | break; | |
1035 | ||
1036 | case ACTION_READWRITE: | |
1037 | mode = O_RDWR; | |
1038 | break; | |
1039 | ||
1040 | default: | |
1041 | internal_error ("regular_file(): Bad action"); | |
1042 | } | |
1043 | ||
1044 | switch (status) | |
1045 | { | |
1046 | case STATUS_NEW: | |
1047 | mode |= O_CREAT | O_EXCL; | |
1048 | break; | |
1049 | ||
1050 | case STATUS_OLD: /* file must exist, so check for its existence */ | |
1051 | if (stat (path, &statbuf) < 0) | |
1052 | return -1; | |
1053 | break; | |
1054 | ||
1055 | case STATUS_UNKNOWN: | |
1056 | case STATUS_SCRATCH: | |
1057 | mode |= O_CREAT; | |
1058 | break; | |
1059 | ||
1060 | case STATUS_REPLACE: | |
3f4f29f6 | 1061 | mode |= O_CREAT | O_TRUNC; |
4ee9c684 | 1062 | break; |
1063 | ||
1064 | default: | |
1065 | internal_error ("regular_file(): Bad status"); | |
1066 | } | |
1067 | ||
1068 | // mode |= O_LARGEFILE; | |
1069 | ||
1070 | return open (path, mode, | |
1071 | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH); | |
1072 | } | |
1073 | ||
1074 | ||
1075 | /* open_external()-- Open an external file, unix specific version. | |
1076 | * Returns NULL on operating system error. */ | |
1077 | ||
1078 | stream * | |
1079 | open_external (unit_action action, unit_status status) | |
1080 | { | |
1081 | int fd, prot; | |
1082 | ||
1083 | fd = | |
1084 | (status == STATUS_SCRATCH) ? tempfile () : regular_file (action, status); | |
1085 | ||
1086 | if (fd < 0) | |
1087 | return NULL; | |
1088 | fd = fix_fd (fd); | |
1089 | ||
1090 | switch (action) | |
1091 | { | |
1092 | case ACTION_READ: | |
1093 | prot = PROT_READ; | |
1094 | break; | |
1095 | ||
1096 | case ACTION_WRITE: | |
1097 | prot = PROT_WRITE; | |
1098 | break; | |
1099 | ||
1100 | case ACTION_READWRITE: | |
1101 | prot = PROT_READ | PROT_WRITE; | |
1102 | break; | |
1103 | ||
1104 | default: | |
1105 | internal_error ("open_external(): Bad action"); | |
1106 | } | |
1107 | ||
1108 | /* If this is a scratch file, we can unlink it now and the file will | |
1109 | * go away when it is closed. */ | |
1110 | ||
1111 | if (status == STATUS_SCRATCH) | |
1112 | unlink (ioparm.file); | |
1113 | ||
1114 | return fd_to_stream (fd, prot); | |
1115 | } | |
1116 | ||
1117 | ||
1118 | /* input_stream()-- Return a stream pointer to the default input stream. | |
1119 | * Called on initialization. */ | |
1120 | ||
1121 | stream * | |
1122 | input_stream (void) | |
1123 | { | |
1124 | ||
1125 | return fd_to_stream (STDIN_FILENO, PROT_READ); | |
1126 | } | |
1127 | ||
1128 | ||
1129 | /* output_stream()-- Return a stream pointer to the default input stream. | |
1130 | * Called on initialization. */ | |
1131 | ||
1132 | stream * | |
1133 | output_stream (void) | |
1134 | { | |
1135 | ||
1136 | return fd_to_stream (STDOUT_FILENO, PROT_WRITE); | |
1137 | } | |
1138 | ||
1139 | ||
1140 | /* init_error_stream()-- Return a pointer to the error stream. This | |
1141 | * subroutine is called when the stream is needed, rather than at | |
1142 | * initialization. We want to work even if memory has been seriously | |
1143 | * corrupted. */ | |
1144 | ||
1145 | stream * | |
1146 | init_error_stream (void) | |
1147 | { | |
1148 | static unix_stream error; | |
1149 | ||
1150 | memset (&error, '\0', sizeof (error)); | |
1151 | ||
1152 | error.fd = options.use_stderr ? STDERR_FILENO : STDOUT_FILENO; | |
1153 | ||
1154 | error.st.alloc_w_at = (void *) fd_alloc_w_at; | |
1155 | error.st.sfree = (void *) fd_sfree; | |
1156 | ||
1157 | error.unbuffered = 1; | |
1158 | error.buffer = error.small_buffer; | |
1159 | ||
1160 | return (stream *) & error; | |
1161 | } | |
1162 | ||
1163 | ||
1164 | /* compare_file_filename()-- Given an open stream and a fortran string | |
1165 | * that is a filename, figure out if the file is the same as the | |
1166 | * filename. */ | |
1167 | ||
1168 | int | |
1169 | compare_file_filename (stream * s, const char *name, int len) | |
1170 | { | |
1171 | char path[PATH_MAX + 1]; | |
1172 | struct stat st1, st2; | |
1173 | ||
1174 | if (unpack_filename (path, name, len)) | |
1175 | return 0; /* Can't be the same */ | |
1176 | ||
1177 | /* If the filename doesn't exist, then there is no match with the | |
1178 | * existing file. */ | |
1179 | ||
1180 | if (stat (path, &st1) < 0) | |
1181 | return 0; | |
1182 | ||
1183 | fstat (((unix_stream *) s)->fd, &st2); | |
1184 | ||
1185 | return (st1.st_dev == st2.st_dev) && (st1.st_ino == st2.st_ino); | |
1186 | } | |
1187 | ||
1188 | ||
1189 | /* find_file0()-- Recursive work function for find_file() */ | |
1190 | ||
f02dd226 | 1191 | static gfc_unit * |
1192 | find_file0 (gfc_unit * u, struct stat *st1) | |
4ee9c684 | 1193 | { |
1194 | struct stat st2; | |
f02dd226 | 1195 | gfc_unit *v; |
4ee9c684 | 1196 | |
1197 | if (u == NULL) | |
1198 | return NULL; | |
1199 | ||
1200 | if (fstat (((unix_stream *) u->s)->fd, &st2) >= 0 && | |
1201 | st1->st_dev == st2.st_dev && st1->st_ino == st2.st_ino) | |
1202 | return u; | |
1203 | ||
1204 | v = find_file0 (u->left, st1); | |
1205 | if (v != NULL) | |
1206 | return v; | |
1207 | ||
1208 | v = find_file0 (u->right, st1); | |
1209 | if (v != NULL) | |
1210 | return v; | |
1211 | ||
1212 | return NULL; | |
1213 | } | |
1214 | ||
1215 | ||
1216 | /* find_file()-- Take the current filename and see if there is a unit | |
1217 | * that has the file already open. Returns a pointer to the unit if so. */ | |
1218 | ||
f02dd226 | 1219 | gfc_unit * |
4ee9c684 | 1220 | find_file (void) |
1221 | { | |
1222 | char path[PATH_MAX + 1]; | |
1223 | struct stat statbuf; | |
1224 | ||
1225 | if (unpack_filename (path, ioparm.file, ioparm.file_len)) | |
1226 | return NULL; | |
1227 | ||
1228 | if (stat (path, &statbuf) < 0) | |
1229 | return NULL; | |
1230 | ||
1231 | return find_file0 (g.unit_root, &statbuf); | |
1232 | } | |
1233 | ||
1234 | ||
1235 | /* stream_at_bof()-- Returns nonzero if the stream is at the beginning | |
1236 | * of the file. */ | |
1237 | ||
1238 | int | |
1239 | stream_at_bof (stream * s) | |
1240 | { | |
1241 | unix_stream *us; | |
1242 | ||
1243 | us = (unix_stream *) s; | |
1244 | ||
1245 | if (!us->mmaped) | |
1246 | return 0; /* File is not seekable */ | |
1247 | ||
1248 | return us->logical_offset == 0; | |
1249 | } | |
1250 | ||
1251 | ||
1252 | /* stream_at_eof()-- Returns nonzero if the stream is at the beginning | |
1253 | * of the file. */ | |
1254 | ||
1255 | int | |
1256 | stream_at_eof (stream * s) | |
1257 | { | |
1258 | unix_stream *us; | |
1259 | ||
1260 | us = (unix_stream *) s; | |
1261 | ||
1262 | if (!us->mmaped) | |
1263 | return 0; /* File is not seekable */ | |
1264 | ||
1265 | return us->logical_offset == us->dirty_offset; | |
1266 | } | |
1267 | ||
1268 | ||
1269 | /* delete_file()-- Given a unit structure, delete the file associated | |
1270 | * with the unit. Returns nonzero if something went wrong. */ | |
1271 | ||
1272 | int | |
f02dd226 | 1273 | delete_file (gfc_unit * u) |
4ee9c684 | 1274 | { |
1275 | char path[PATH_MAX + 1]; | |
1276 | ||
1277 | if (unpack_filename (path, u->file, u->file_len)) | |
1278 | { /* Shouldn't be possible */ | |
1279 | errno = ENOENT; | |
1280 | return 1; | |
1281 | } | |
1282 | ||
1283 | return unlink (path); | |
1284 | } | |
1285 | ||
1286 | ||
1287 | /* file_exists()-- Returns nonzero if the current filename exists on | |
1288 | * the system */ | |
1289 | ||
1290 | int | |
1291 | file_exists (void) | |
1292 | { | |
1293 | char path[PATH_MAX + 1]; | |
1294 | struct stat statbuf; | |
1295 | ||
1296 | if (unpack_filename (path, ioparm.file, ioparm.file_len)) | |
1297 | return 0; | |
1298 | ||
1299 | if (stat (path, &statbuf) < 0) | |
1300 | return 0; | |
1301 | ||
1302 | return 1; | |
1303 | } | |
1304 | ||
1305 | ||
1306 | ||
1307 | static const char *yes = "YES", *no = "NO", *unknown = "UNKNOWN"; | |
1308 | ||
1309 | /* inquire_sequential()-- Given a fortran string, determine if the | |
1310 | * file is suitable for sequential access. Returns a C-style | |
1311 | * string. */ | |
1312 | ||
1313 | const char * | |
1314 | inquire_sequential (const char *string, int len) | |
1315 | { | |
1316 | char path[PATH_MAX + 1]; | |
1317 | struct stat statbuf; | |
1318 | ||
1319 | if (string == NULL || | |
1320 | unpack_filename (path, string, len) || stat (path, &statbuf) < 0) | |
1321 | return unknown; | |
1322 | ||
1323 | if (S_ISREG (statbuf.st_mode) || | |
1324 | S_ISCHR (statbuf.st_mode) || S_ISFIFO (statbuf.st_mode)) | |
1325 | return yes; | |
1326 | ||
1327 | if (S_ISDIR (statbuf.st_mode) || S_ISBLK (statbuf.st_mode)) | |
1328 | return no; | |
1329 | ||
1330 | return unknown; | |
1331 | } | |
1332 | ||
1333 | ||
1334 | /* inquire_direct()-- Given a fortran string, determine if the file is | |
1335 | * suitable for direct access. Returns a C-style string. */ | |
1336 | ||
1337 | const char * | |
1338 | inquire_direct (const char *string, int len) | |
1339 | { | |
1340 | char path[PATH_MAX + 1]; | |
1341 | struct stat statbuf; | |
1342 | ||
1343 | if (string == NULL || | |
1344 | unpack_filename (path, string, len) || stat (path, &statbuf) < 0) | |
1345 | return unknown; | |
1346 | ||
1347 | if (S_ISREG (statbuf.st_mode) || S_ISBLK (statbuf.st_mode)) | |
1348 | return yes; | |
1349 | ||
1350 | if (S_ISDIR (statbuf.st_mode) || | |
1351 | S_ISCHR (statbuf.st_mode) || S_ISFIFO (statbuf.st_mode)) | |
1352 | return no; | |
1353 | ||
1354 | return unknown; | |
1355 | } | |
1356 | ||
1357 | ||
1358 | /* inquire_formatted()-- Given a fortran string, determine if the file | |
1359 | * is suitable for formatted form. Returns a C-style string. */ | |
1360 | ||
1361 | const char * | |
1362 | inquire_formatted (const char *string, int len) | |
1363 | { | |
1364 | char path[PATH_MAX + 1]; | |
1365 | struct stat statbuf; | |
1366 | ||
1367 | if (string == NULL || | |
1368 | unpack_filename (path, string, len) || stat (path, &statbuf) < 0) | |
1369 | return unknown; | |
1370 | ||
1371 | if (S_ISREG (statbuf.st_mode) || | |
1372 | S_ISBLK (statbuf.st_mode) || | |
1373 | S_ISCHR (statbuf.st_mode) || S_ISFIFO (statbuf.st_mode)) | |
1374 | return yes; | |
1375 | ||
1376 | if (S_ISDIR (statbuf.st_mode)) | |
1377 | return no; | |
1378 | ||
1379 | return unknown; | |
1380 | } | |
1381 | ||
1382 | ||
1383 | /* inquire_unformatted()-- Given a fortran string, determine if the file | |
1384 | * is suitable for unformatted form. Returns a C-style string. */ | |
1385 | ||
1386 | const char * | |
1387 | inquire_unformatted (const char *string, int len) | |
1388 | { | |
1389 | ||
1390 | return inquire_formatted (string, len); | |
1391 | } | |
1392 | ||
1393 | ||
1394 | /* inquire_access()-- Given a fortran string, determine if the file is | |
1395 | * suitable for access. */ | |
1396 | ||
1397 | static const char * | |
1398 | inquire_access (const char *string, int len, int mode) | |
1399 | { | |
1400 | char path[PATH_MAX + 1]; | |
1401 | ||
1402 | if (string == NULL || unpack_filename (path, string, len) || | |
1403 | access (path, mode) < 0) | |
1404 | return no; | |
1405 | ||
1406 | return yes; | |
1407 | } | |
1408 | ||
1409 | ||
1410 | /* inquire_read()-- Given a fortran string, determine if the file is | |
1411 | * suitable for READ access. */ | |
1412 | ||
1413 | const char * | |
1414 | inquire_read (const char *string, int len) | |
1415 | { | |
1416 | ||
1417 | return inquire_access (string, len, R_OK); | |
1418 | } | |
1419 | ||
1420 | ||
1421 | /* inquire_write()-- Given a fortran string, determine if the file is | |
1422 | * suitable for READ access. */ | |
1423 | ||
1424 | const char * | |
1425 | inquire_write (const char *string, int len) | |
1426 | { | |
1427 | ||
1428 | return inquire_access (string, len, W_OK); | |
1429 | } | |
1430 | ||
1431 | ||
1432 | /* inquire_readwrite()-- Given a fortran string, determine if the file is | |
1433 | * suitable for read and write access. */ | |
1434 | ||
1435 | const char * | |
1436 | inquire_readwrite (const char *string, int len) | |
1437 | { | |
1438 | ||
1439 | return inquire_access (string, len, R_OK | W_OK); | |
1440 | } | |
1441 | ||
1442 | ||
1443 | /* file_length()-- Return the file length in bytes, -1 if unknown */ | |
1444 | ||
b093181d | 1445 | gfc_offset |
4ee9c684 | 1446 | file_length (stream * s) |
1447 | { | |
1448 | ||
1449 | return ((unix_stream *) s)->file_length; | |
1450 | } | |
1451 | ||
1452 | ||
1453 | /* file_position()-- Return the current position of the file */ | |
1454 | ||
b093181d | 1455 | gfc_offset |
4ee9c684 | 1456 | file_position (stream * s) |
1457 | { | |
1458 | ||
1459 | return ((unix_stream *) s)->logical_offset; | |
1460 | } | |
1461 | ||
1462 | ||
1463 | /* is_seekable()-- Return nonzero if the stream is seekable, zero if | |
1464 | * it is not */ | |
1465 | ||
1466 | int | |
1467 | is_seekable (stream * s) | |
1468 | { | |
5a78b88f | 1469 | /* by convention, if file_length == -1, the file is not seekable |
1470 | note that a mmapped file is always seekable, an fd_ file may | |
1471 | or may not be. */ | |
1472 | return ((unix_stream *) s)->file_length!=-1; | |
4ee9c684 | 1473 | } |
1474 | ||
b0342e98 | 1475 | try |
1476 | flush (stream *s) | |
1477 | { | |
1478 | return fd_flush( (unix_stream *) s); | |
1479 | } | |
1480 | ||
4ee9c684 | 1481 | |
1482 | /* How files are stored: This is an operating-system specific issue, | |
1483 | and therefore belongs here. There are three cases to consider. | |
1484 | ||
1485 | Direct Access: | |
1486 | Records are written as block of bytes corresponding to the record | |
1487 | length of the file. This goes for both formatted and unformatted | |
1488 | records. Positioning is done explicitly for each data transfer, | |
1489 | so positioning is not much of an issue. | |
1490 | ||
1491 | Sequential Formatted: | |
1492 | Records are separated by newline characters. The newline character | |
1493 | is prohibited from appearing in a string. If it does, this will be | |
1494 | messed up on the next read. End of file is also the end of a record. | |
1495 | ||
1496 | Sequential Unformatted: | |
1497 | In this case, we are merely copying bytes to and from main storage, | |
1498 | yet we need to keep track of varying record lengths. We adopt | |
1499 | the solution used by f2c. Each record contains a pair of length | |
1500 | markers: | |
1501 | ||
1502 | Length of record n in bytes | |
1503 | Data of record n | |
1504 | Length of record n in bytes | |
1505 | ||
1506 | Length of record n+1 in bytes | |
1507 | Data of record n+1 | |
1508 | Length of record n+1 in bytes | |
1509 | ||
1510 | The length is stored at the end of a record to allow backspacing to the | |
1511 | previous record. Between data transfer statements, the file pointer | |
1512 | is left pointing to the first length of the current record. | |
1513 | ||
1514 | ENDFILE records are never explicitly stored. | |
1515 | ||
1516 | */ |