1 /* Copyright (C) 2002, 2003, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
2 Contributed by Andy Vaught
3 F2003 I/O support contributed by Jerry DeLisle
5 This file is part of the GNU Fortran 95 runtime library (libgfortran).
7 Libgfortran is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 Libgfortran is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 Under Section 7 of GPL version 3, you are granted additional
18 permissions described in the GCC Runtime Library Exception, version
19 3.1, as published by the Free Software Foundation.
21 You should have received a copy of the GNU General Public License and
22 a copy of the GCC Runtime Library Exception along with this program;
23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 <http://www.gnu.org/licenses/>. */
35 UNIT_LOCK is a master lock, protecting UNIT_ROOT tree and UNIT_CACHE.
36 Concurrent use of different units should be supported, so
37 each unit has its own lock, LOCK.
38 Open should be atomic with its reopening of units and list_read.c
39 in several places needs find_unit another unit while holding stdin
40 unit's lock, so it must be possible to acquire UNIT_LOCK while holding
41 some unit's lock. Therefore to avoid deadlocks, it is forbidden
42 to acquire unit's private locks while holding UNIT_LOCK, except
43 for freshly created units (where no other thread can get at their
44 address yet) or when using just trylock rather than lock operation.
45 In addition to unit's private lock each unit has a WAITERS counter
46 and CLOSED flag. WAITERS counter must be either only
47 atomically incremented/decremented in all places (if atomic builtins
48 are supported), or protected by UNIT_LOCK in all places (otherwise).
49 CLOSED flag must be always protected by unit's LOCK.
50 After finding a unit in UNIT_CACHE or UNIT_ROOT with UNIT_LOCK held,
51 WAITERS must be incremented to avoid concurrent close from freeing
52 the unit between unlocking UNIT_LOCK and acquiring unit's LOCK.
53 Unit freeing is always done under UNIT_LOCK. If close_unit sees any
54 WAITERS, it doesn't free the unit but instead sets the CLOSED flag
55 and the thread that decrements WAITERS to zero while CLOSED flag is
56 set is responsible for freeing it (while holding UNIT_LOCK).
57 flush_all_units operation is iterating over the unit tree with
58 increasing UNIT_NUMBER while holding UNIT_LOCK and attempting to
59 flush each unit (and therefore needs the unit's LOCK held as well).
60 To avoid deadlocks, it just trylocks the LOCK and if unsuccessful,
61 remembers the current unit's UNIT_NUMBER, unlocks UNIT_LOCK, acquires
62 unit's LOCK and after flushing reacquires UNIT_LOCK and restarts with
63 the smallest UNIT_NUMBER above the last one flushed.
65 If find_unit/find_or_create_unit/find_file/get_unit routines return
66 non-NULL, the returned unit has its private lock locked and when the
67 caller is done with it, it must call either unlock_unit or close_unit
68 on it. unlock_unit or close_unit must be always called only with the
71 /* Subroutines related to units */
73 GFC_INTEGER_4 next_available_newunit
;
74 #define GFC_FIRST_NEWUNIT -10
77 static gfc_unit
*unit_cache
[CACHE_SIZE
];
78 gfc_offset max_offset
;
80 #ifdef __GTHREAD_MUTEX_INIT
81 __gthread_mutex_t unit_lock
= __GTHREAD_MUTEX_INIT
;
83 __gthread_mutex_t unit_lock
;
86 /* We use these filenames for error reporting. */
88 static char stdin_name
[] = "stdin";
89 static char stdout_name
[] = "stdout";
90 static char stderr_name
[] = "stderr";
92 /* This implementation is based on Stefan Nilsson's article in the
93 * July 1997 Doctor Dobb's Journal, "Treaps in Java". */
95 /* pseudo_random()-- Simple linear congruential pseudorandom number
96 * generator. The period of this generator is 44071, which is plenty
97 * for our purposes. */
102 static int x0
= 5341;
104 x0
= (22611 * x0
+ 10) % 44071;
109 /* rotate_left()-- Rotate the treap left */
112 rotate_left (gfc_unit
* t
)
117 t
->right
= t
->right
->left
;
124 /* rotate_right()-- Rotate the treap right */
127 rotate_right (gfc_unit
* t
)
132 t
->left
= t
->left
->right
;
140 compare (int a
, int b
)
151 /* insert()-- Recursive insertion function. Returns the updated treap. */
154 insert (gfc_unit
*new, gfc_unit
*t
)
161 c
= compare (new->unit_number
, t
->unit_number
);
165 t
->left
= insert (new, t
->left
);
166 if (t
->priority
< t
->left
->priority
)
167 t
= rotate_right (t
);
172 t
->right
= insert (new, t
->right
);
173 if (t
->priority
< t
->right
->priority
)
178 internal_error (NULL
, "insert(): Duplicate key found!");
184 /* insert_unit()-- Create a new node, insert it into the treap. */
189 gfc_unit
*u
= get_mem (sizeof (gfc_unit
));
190 memset (u
, '\0', sizeof (gfc_unit
));
192 #ifdef __GTHREAD_MUTEX_INIT
194 __gthread_mutex_t tmp
= __GTHREAD_MUTEX_INIT
;
198 __GTHREAD_MUTEX_INIT_FUNCTION (&u
->lock
);
200 __gthread_mutex_lock (&u
->lock
);
201 u
->priority
= pseudo_random ();
202 unit_root
= insert (u
, unit_root
);
207 /* destroy_unit_mutex()-- Destroy the mutex and free memory of unit. */
210 destroy_unit_mutex (gfc_unit
* u
)
212 __gthread_mutex_destroy (&u
->lock
);
218 delete_root (gfc_unit
* t
)
224 if (t
->right
== NULL
)
227 if (t
->left
->priority
> t
->right
->priority
)
229 temp
= rotate_right (t
);
230 temp
->right
= delete_root (t
);
234 temp
= rotate_left (t
);
235 temp
->left
= delete_root (t
);
242 /* delete_treap()-- Delete an element from a tree. The 'old' value
243 * does not necessarily have to point to the element to be deleted, it
244 * must just point to a treap structure with the key to be deleted.
245 * Returns the new root node of the tree. */
248 delete_treap (gfc_unit
* old
, gfc_unit
* t
)
255 c
= compare (old
->unit_number
, t
->unit_number
);
258 t
->left
= delete_treap (old
, t
->left
);
260 t
->right
= delete_treap (old
, t
->right
);
268 /* delete_unit()-- Delete a unit from a tree */
271 delete_unit (gfc_unit
* old
)
273 unit_root
= delete_treap (old
, unit_root
);
277 /* get_external_unit()-- Given an integer, return a pointer to the unit
278 * structure. Returns NULL if the unit does not exist,
279 * otherwise returns a locked unit. */
282 get_external_unit (int n
, int do_create
)
287 __gthread_mutex_lock (&unit_lock
);
289 for (c
= 0; c
< CACHE_SIZE
; c
++)
290 if (unit_cache
[c
] != NULL
&& unit_cache
[c
]->unit_number
== n
)
299 c
= compare (n
, p
->unit_number
);
308 if (p
== NULL
&& do_create
)
316 for (c
= 0; c
< CACHE_SIZE
- 1; c
++)
317 unit_cache
[c
] = unit_cache
[c
+ 1];
319 unit_cache
[CACHE_SIZE
- 1] = p
;
324 /* Newly created units have their lock held already
325 from insert_unit. Just unlock UNIT_LOCK and return. */
326 __gthread_mutex_unlock (&unit_lock
);
334 if (! __gthread_mutex_trylock (&p
->lock
))
336 /* assert (p->closed == 0); */
337 __gthread_mutex_unlock (&unit_lock
);
341 inc_waiting_locked (p
);
344 __gthread_mutex_unlock (&unit_lock
);
348 __gthread_mutex_lock (&p
->lock
);
351 __gthread_mutex_lock (&unit_lock
);
352 __gthread_mutex_unlock (&p
->lock
);
353 if (predec_waiting_locked (p
) == 0)
354 destroy_unit_mutex (p
);
358 dec_waiting_unlocked (p
);
367 return get_external_unit (n
, 0);
372 find_or_create_unit (int n
)
374 return get_external_unit (n
, 1);
379 get_internal_unit (st_parameter_dt
*dtp
)
382 gfc_offset start_record
= 0;
384 /* Allocate memory for a unit structure. */
386 iunit
= get_mem (sizeof (gfc_unit
));
389 generate_error (&dtp
->common
, LIBERROR_INTERNAL_UNIT
, NULL
);
393 memset (iunit
, '\0', sizeof (gfc_unit
));
394 #ifdef __GTHREAD_MUTEX_INIT
396 __gthread_mutex_t tmp
= __GTHREAD_MUTEX_INIT
;
400 __GTHREAD_MUTEX_INIT_FUNCTION (&iunit
->lock
);
402 __gthread_mutex_lock (&iunit
->lock
);
404 iunit
->recl
= dtp
->internal_unit_len
;
406 /* For internal units we set the unit number to -1.
407 Otherwise internal units can be mistaken for a pre-connected unit or
408 some other file I/O unit. */
409 iunit
->unit_number
= -1;
411 /* Set up the looping specification from the array descriptor, if any. */
413 if (is_array_io (dtp
))
415 iunit
->rank
= GFC_DESCRIPTOR_RANK (dtp
->internal_unit_desc
);
416 iunit
->ls
= (array_loop_spec
*)
417 get_mem (iunit
->rank
* sizeof (array_loop_spec
));
418 dtp
->internal_unit_len
*=
419 init_loop_spec (dtp
->internal_unit_desc
, iunit
->ls
, &start_record
);
421 start_record
*= iunit
->recl
;
424 /* Set initial values for unit parameters. */
426 iunit
->s
= open_internal (dtp
->internal_unit
- start_record
,
427 dtp
->internal_unit_len
, -start_record
);
428 iunit
->bytes_left
= iunit
->recl
;
429 iunit
->last_record
=0;
431 iunit
->current_record
=0;
433 iunit
->endfile
= NO_ENDFILE
;
435 /* Set flags for the internal unit. */
437 iunit
->flags
.access
= ACCESS_SEQUENTIAL
;
438 iunit
->flags
.action
= ACTION_READWRITE
;
439 iunit
->flags
.blank
= BLANK_NULL
;
440 iunit
->flags
.form
= FORM_FORMATTED
;
441 iunit
->flags
.pad
= PAD_YES
;
442 iunit
->flags
.status
= STATUS_UNSPECIFIED
;
443 iunit
->flags
.sign
= SIGN_SUPPRESS
;
444 iunit
->flags
.decimal
= DECIMAL_POINT
;
445 iunit
->flags
.encoding
= ENCODING_DEFAULT
;
446 iunit
->flags
.async
= ASYNC_NO
;
447 iunit
->flags
.round
= ROUND_COMPATIBLE
;
449 /* Initialize the data transfer parameters. */
451 dtp
->u
.p
.advance_status
= ADVANCE_YES
;
452 dtp
->u
.p
.seen_dollar
= 0;
454 dtp
->u
.p
.pending_spaces
= 0;
455 dtp
->u
.p
.max_pos
= 0;
458 /* This flag tells us the unit is assigned to internal I/O. */
460 dtp
->u
.p
.unit_is_internal
= 1;
466 /* free_internal_unit()-- Free memory allocated for internal units if any. */
468 free_internal_unit (st_parameter_dt
*dtp
)
470 if (!is_internal_unit (dtp
))
473 if (dtp
->u
.p
.current_unit
!= NULL
)
475 if (dtp
->u
.p
.current_unit
->ls
!= NULL
)
476 free_mem (dtp
->u
.p
.current_unit
->ls
);
478 if (dtp
->u
.p
.current_unit
->s
)
479 free_mem (dtp
->u
.p
.current_unit
->s
);
481 destroy_unit_mutex (dtp
->u
.p
.current_unit
);
487 /* get_unit()-- Returns the unit structure associated with the integer
488 unit or the internal file. */
491 get_unit (st_parameter_dt
*dtp
, int do_create
)
494 if ((dtp
->common
.flags
& IOPARM_DT_HAS_INTERNAL_UNIT
) != 0)
495 return get_internal_unit(dtp
);
497 /* Has to be an external unit. */
499 dtp
->u
.p
.unit_is_internal
= 0;
500 dtp
->internal_unit_desc
= NULL
;
502 return get_external_unit (dtp
->common
.unit
, do_create
);
506 /*************************/
507 /* Initialize everything. */
515 #ifndef __GTHREAD_MUTEX_INIT
516 __GTHREAD_MUTEX_INIT_FUNCTION (&unit_lock
);
519 next_available_newunit
= GFC_FIRST_NEWUNIT
;
521 if (options
.stdin_unit
>= 0)
523 u
= insert_unit (options
.stdin_unit
);
524 u
->s
= input_stream ();
526 u
->flags
.action
= ACTION_READ
;
528 u
->flags
.access
= ACCESS_SEQUENTIAL
;
529 u
->flags
.form
= FORM_FORMATTED
;
530 u
->flags
.status
= STATUS_OLD
;
531 u
->flags
.blank
= BLANK_NULL
;
532 u
->flags
.pad
= PAD_YES
;
533 u
->flags
.position
= POSITION_ASIS
;
534 u
->flags
.sign
= SIGN_SUPPRESS
;
535 u
->flags
.decimal
= DECIMAL_POINT
;
536 u
->flags
.encoding
= ENCODING_DEFAULT
;
537 u
->flags
.async
= ASYNC_NO
;
538 u
->flags
.round
= ROUND_COMPATIBLE
;
540 u
->recl
= options
.default_recl
;
541 u
->endfile
= NO_ENDFILE
;
543 u
->file_len
= strlen (stdin_name
);
544 u
->file
= get_mem (u
->file_len
);
545 memmove (u
->file
, stdin_name
, u
->file_len
);
549 __gthread_mutex_unlock (&u
->lock
);
552 if (options
.stdout_unit
>= 0)
554 u
= insert_unit (options
.stdout_unit
);
555 u
->s
= output_stream ();
557 u
->flags
.action
= ACTION_WRITE
;
559 u
->flags
.access
= ACCESS_SEQUENTIAL
;
560 u
->flags
.form
= FORM_FORMATTED
;
561 u
->flags
.status
= STATUS_OLD
;
562 u
->flags
.blank
= BLANK_NULL
;
563 u
->flags
.position
= POSITION_ASIS
;
564 u
->flags
.sign
= SIGN_SUPPRESS
;
565 u
->flags
.decimal
= DECIMAL_POINT
;
566 u
->flags
.encoding
= ENCODING_DEFAULT
;
567 u
->flags
.async
= ASYNC_NO
;
568 u
->flags
.round
= ROUND_COMPATIBLE
;
570 u
->recl
= options
.default_recl
;
571 u
->endfile
= AT_ENDFILE
;
573 u
->file_len
= strlen (stdout_name
);
574 u
->file
= get_mem (u
->file_len
);
575 memmove (u
->file
, stdout_name
, u
->file_len
);
579 __gthread_mutex_unlock (&u
->lock
);
582 if (options
.stderr_unit
>= 0)
584 u
= insert_unit (options
.stderr_unit
);
585 u
->s
= error_stream ();
587 u
->flags
.action
= ACTION_WRITE
;
589 u
->flags
.access
= ACCESS_SEQUENTIAL
;
590 u
->flags
.form
= FORM_FORMATTED
;
591 u
->flags
.status
= STATUS_OLD
;
592 u
->flags
.blank
= BLANK_NULL
;
593 u
->flags
.position
= POSITION_ASIS
;
594 u
->flags
.sign
= SIGN_SUPPRESS
;
595 u
->flags
.decimal
= DECIMAL_POINT
;
596 u
->flags
.encoding
= ENCODING_DEFAULT
;
597 u
->flags
.async
= ASYNC_NO
;
598 u
->flags
.round
= ROUND_COMPATIBLE
;
600 u
->recl
= options
.default_recl
;
601 u
->endfile
= AT_ENDFILE
;
603 u
->file_len
= strlen (stderr_name
);
604 u
->file
= get_mem (u
->file_len
);
605 memmove (u
->file
, stderr_name
, u
->file_len
);
607 fbuf_init (u
, 256); /* 256 bytes should be enough, probably not doing
608 any kind of exotic formatting to stderr. */
610 __gthread_mutex_unlock (&u
->lock
);
613 /* Calculate the maximum file offset in a portable manner.
614 max will be the largest signed number for the type gfc_offset.
615 set a 1 in the LSB and keep a running sum, stopping at MSB-1 bit. */
617 for (i
= 0; i
< sizeof (max_offset
) * 8 - 1; i
++)
618 max_offset
= max_offset
+ ((gfc_offset
) 1 << i
);
623 close_unit_1 (gfc_unit
*u
, int locked
)
627 /* If there are previously written bytes from a write with ADVANCE="no"
628 Reposition the buffer before closing. */
629 if (u
->previous_nonadvancing_write
)
630 finish_last_advance_record (u
);
632 rc
= (u
->s
== NULL
) ? 0 : sclose (u
->s
) == -1;
636 __gthread_mutex_lock (&unit_lock
);
638 for (i
= 0; i
< CACHE_SIZE
; i
++)
639 if (unit_cache
[i
] == u
)
640 unit_cache
[i
] = NULL
;
649 free_format_hash_table (u
);
653 __gthread_mutex_unlock (&u
->lock
);
655 /* If there are any threads waiting in find_unit for this unit,
656 avoid freeing the memory, the last such thread will free it
659 destroy_unit_mutex (u
);
662 __gthread_mutex_unlock (&unit_lock
);
668 unlock_unit (gfc_unit
*u
)
670 __gthread_mutex_unlock (&u
->lock
);
673 /* close_unit()-- Close a unit. The stream is closed, and any memory
674 associated with the stream is freed. Returns nonzero on I/O error.
675 Should be called with the u->lock locked. */
678 close_unit (gfc_unit
*u
)
680 return close_unit_1 (u
, 0);
684 /* close_units()-- Delete units on completion. We just keep deleting
685 the root of the treap until there is nothing left.
686 Not sure what to do with locking here. Some other thread might be
687 holding some unit's lock and perhaps hold it indefinitely
688 (e.g. waiting for input from some pipe) and close_units shouldn't
689 delay the program too much. */
694 __gthread_mutex_lock (&unit_lock
);
695 while (unit_root
!= NULL
)
696 close_unit_1 (unit_root
, 1);
697 __gthread_mutex_unlock (&unit_lock
);
701 /* update_position()-- Update the flags position for later use by inquire. */
704 update_position (gfc_unit
*u
)
706 if (stell (u
->s
) == 0)
707 u
->flags
.position
= POSITION_REWIND
;
708 else if (file_length (u
->s
) == stell (u
->s
))
709 u
->flags
.position
= POSITION_APPEND
;
711 u
->flags
.position
= POSITION_ASIS
;
715 /* High level interface to truncate a file safely, i.e. flush format
716 buffers, check that it's a regular file, and generate error if that
717 occurs. Just like POSIX ftruncate, returns 0 on success, -1 on
721 unit_truncate (gfc_unit
* u
, gfc_offset pos
, st_parameter_common
* common
)
725 /* Make sure format buffer is flushed. */
726 if (u
->flags
.form
== FORM_FORMATTED
)
728 if (u
->mode
== READING
)
729 pos
+= fbuf_reset (u
);
731 fbuf_flush (u
, u
->mode
);
734 /* Don't try to truncate a special file, just pretend that it
736 if (is_special (u
->s
) || !is_seekable (u
->s
))
742 /* struncate() should flush the stream buffer if necessary, so don't
743 bother calling sflush() here. */
744 ret
= struncate (u
->s
, pos
);
748 generate_error (common
, LIBERROR_OS
, NULL
);
749 u
->endfile
= NO_ENDFILE
;
750 u
->flags
.position
= POSITION_ASIS
;
754 u
->endfile
= AT_ENDFILE
;
755 u
->flags
.position
= POSITION_APPEND
;
762 /* filename_from_unit()-- If the unit_number exists, return a pointer to the
763 name of the associated file, otherwise return the empty string. The caller
764 must free memory allocated for the filename string. */
767 filename_from_unit (int n
)
777 c
= compare (n
, u
->unit_number
);
786 /* Get the filename. */
789 filename
= (char *) get_mem (u
->file_len
+ 1);
790 unpack_filename (filename
, u
->file
, u
->file_len
);
794 return (char *) NULL
;
798 finish_last_advance_record (gfc_unit
*u
)
801 if (u
->saved_pos
> 0)
802 fbuf_seek (u
, u
->saved_pos
, SEEK_CUR
);
804 if (!(u
->unit_number
== options
.stdout_unit
805 || u
->unit_number
== options
.stderr_unit
))
812 char *p
= fbuf_alloc (u
, len
);
814 os_error ("Completing record after ADVANCE_NO failed");
821 fbuf_flush (u
, u
->mode
);
824 /* Assign a negative number for NEWUNIT in OPEN statements. */
826 get_unique_unit_number (st_parameter_open
*opp
)
830 __gthread_mutex_lock (&unit_lock
);
831 num
= next_available_newunit
--;
833 /* Do not allow NEWUNIT numbers to wrap. */
834 if (next_available_newunit
>= GFC_FIRST_NEWUNIT
)
836 __gthread_mutex_unlock (&unit_lock
);
837 generate_error (&opp
->common
, LIBERROR_INTERNAL
, "NEWUNIT exhausted");
840 __gthread_mutex_unlock (&unit_lock
);