1 /* Copyright (C) 2002, 2003, 2005, 2007, 2008, 2009, 2010, 2011
2 Free Software Foundation, Inc.
3 Contributed by Andy Vaught
4 F2003 I/O support contributed by Jerry DeLisle
6 This file is part of the GNU Fortran runtime library (libgfortran).
8 Libgfortran is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 Libgfortran is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 Under Section 7 of GPL version 3, you are granted additional
19 permissions described in the GCC Runtime Library Exception, version
20 3.1, as published by the Free Software Foundation.
22 You should have received a copy of the GNU General Public License and
23 a copy of the GCC Runtime Library Exception along with this program;
24 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 <http://www.gnu.org/licenses/>. */
37 UNIT_LOCK is a master lock, protecting UNIT_ROOT tree and UNIT_CACHE.
38 Concurrent use of different units should be supported, so
39 each unit has its own lock, LOCK.
40 Open should be atomic with its reopening of units and list_read.c
41 in several places needs find_unit another unit while holding stdin
42 unit's lock, so it must be possible to acquire UNIT_LOCK while holding
43 some unit's lock. Therefore to avoid deadlocks, it is forbidden
44 to acquire unit's private locks while holding UNIT_LOCK, except
45 for freshly created units (where no other thread can get at their
46 address yet) or when using just trylock rather than lock operation.
47 In addition to unit's private lock each unit has a WAITERS counter
48 and CLOSED flag. WAITERS counter must be either only
49 atomically incremented/decremented in all places (if atomic builtins
50 are supported), or protected by UNIT_LOCK in all places (otherwise).
51 CLOSED flag must be always protected by unit's LOCK.
52 After finding a unit in UNIT_CACHE or UNIT_ROOT with UNIT_LOCK held,
53 WAITERS must be incremented to avoid concurrent close from freeing
54 the unit between unlocking UNIT_LOCK and acquiring unit's LOCK.
55 Unit freeing is always done under UNIT_LOCK. If close_unit sees any
56 WAITERS, it doesn't free the unit but instead sets the CLOSED flag
57 and the thread that decrements WAITERS to zero while CLOSED flag is
58 set is responsible for freeing it (while holding UNIT_LOCK).
59 flush_all_units operation is iterating over the unit tree with
60 increasing UNIT_NUMBER while holding UNIT_LOCK and attempting to
61 flush each unit (and therefore needs the unit's LOCK held as well).
62 To avoid deadlocks, it just trylocks the LOCK and if unsuccessful,
63 remembers the current unit's UNIT_NUMBER, unlocks UNIT_LOCK, acquires
64 unit's LOCK and after flushing reacquires UNIT_LOCK and restarts with
65 the smallest UNIT_NUMBER above the last one flushed.
67 If find_unit/find_or_create_unit/find_file/get_unit routines return
68 non-NULL, the returned unit has its private lock locked and when the
69 caller is done with it, it must call either unlock_unit or close_unit
70 on it. unlock_unit or close_unit must be always called only with the
73 /* Subroutines related to units */
75 /* Unit number to be assigned when NEWUNIT is used in an OPEN statement. */
76 #define GFC_FIRST_NEWUNIT -10
77 static GFC_INTEGER_4 next_available_newunit = GFC_FIRST_NEWUNIT;
80 static gfc_unit *unit_cache[CACHE_SIZE];
81 gfc_offset max_offset;
83 #ifdef __GTHREAD_MUTEX_INIT
84 __gthread_mutex_t unit_lock = __GTHREAD_MUTEX_INIT;
86 __gthread_mutex_t unit_lock;
89 /* We use these filenames for error reporting. */
91 static char stdin_name[] = "stdin";
92 static char stdout_name[] = "stdout";
93 static char stderr_name[] = "stderr";
95 /* This implementation is based on Stefan Nilsson's article in the
96 * July 1997 Doctor Dobb's Journal, "Treaps in Java". */
98 /* pseudo_random()-- Simple linear congruential pseudorandom number
99 * generator. The period of this generator is 44071, which is plenty
100 * for our purposes. */
105 static int x0 = 5341;
107 x0 = (22611 * x0 + 10) % 44071;
112 /* rotate_left()-- Rotate the treap left */
115 rotate_left (gfc_unit * t)
120 t->right = t->right->left;
127 /* rotate_right()-- Rotate the treap right */
130 rotate_right (gfc_unit * t)
135 t->left = t->left->right;
143 compare (int a, int b)
154 /* insert()-- Recursive insertion function. Returns the updated treap. */
157 insert (gfc_unit *new, gfc_unit *t)
164 c = compare (new->unit_number, t->unit_number);
168 t->left = insert (new, t->left);
169 if (t->priority < t->left->priority)
170 t = rotate_right (t);
175 t->right = insert (new, t->right);
176 if (t->priority < t->right->priority)
181 internal_error (NULL, "insert(): Duplicate key found!");
187 /* insert_unit()-- Create a new node, insert it into the treap. */
192 gfc_unit *u = get_mem (sizeof (gfc_unit));
193 memset (u, '\0', sizeof (gfc_unit));
195 #ifdef __GTHREAD_MUTEX_INIT
197 __gthread_mutex_t tmp = __GTHREAD_MUTEX_INIT;
201 __GTHREAD_MUTEX_INIT_FUNCTION (&u->lock);
203 __gthread_mutex_lock (&u->lock);
204 u->priority = pseudo_random ();
205 unit_root = insert (u, unit_root);
210 /* destroy_unit_mutex()-- Destroy the mutex and free memory of unit. */
213 destroy_unit_mutex (gfc_unit * u)
215 __gthread_mutex_destroy (&u->lock);
221 delete_root (gfc_unit * t)
227 if (t->right == NULL)
230 if (t->left->priority > t->right->priority)
232 temp = rotate_right (t);
233 temp->right = delete_root (t);
237 temp = rotate_left (t);
238 temp->left = delete_root (t);
245 /* delete_treap()-- Delete an element from a tree. The 'old' value
246 * does not necessarily have to point to the element to be deleted, it
247 * must just point to a treap structure with the key to be deleted.
248 * Returns the new root node of the tree. */
251 delete_treap (gfc_unit * old, gfc_unit * t)
258 c = compare (old->unit_number, t->unit_number);
261 t->left = delete_treap (old, t->left);
263 t->right = delete_treap (old, t->right);
271 /* delete_unit()-- Delete a unit from a tree */
274 delete_unit (gfc_unit * old)
276 unit_root = delete_treap (old, unit_root);
280 /* get_external_unit()-- Given an integer, return a pointer to the unit
281 * structure. Returns NULL if the unit does not exist,
282 * otherwise returns a locked unit. */
285 get_external_unit (int n, int do_create)
290 __gthread_mutex_lock (&unit_lock);
292 for (c = 0; c < CACHE_SIZE; c++)
293 if (unit_cache[c] != NULL && unit_cache[c]->unit_number == n)
302 c = compare (n, p->unit_number);
311 if (p == NULL && do_create)
319 for (c = 0; c < CACHE_SIZE - 1; c++)
320 unit_cache[c] = unit_cache[c + 1];
322 unit_cache[CACHE_SIZE - 1] = p;
327 /* Newly created units have their lock held already
328 from insert_unit. Just unlock UNIT_LOCK and return. */
329 __gthread_mutex_unlock (&unit_lock);
337 if (! __gthread_mutex_trylock (&p->lock))
339 /* assert (p->closed == 0); */
340 __gthread_mutex_unlock (&unit_lock);
344 inc_waiting_locked (p);
347 __gthread_mutex_unlock (&unit_lock);
351 __gthread_mutex_lock (&p->lock);
354 __gthread_mutex_lock (&unit_lock);
355 __gthread_mutex_unlock (&p->lock);
356 if (predec_waiting_locked (p) == 0)
357 destroy_unit_mutex (p);
361 dec_waiting_unlocked (p);
370 return get_external_unit (n, 0);
375 find_or_create_unit (int n)
377 return get_external_unit (n, 1);
381 /* Helper function to check rank, stride, format string, and namelist.
382 This is used for optimization. You can't trim out blanks or shorten
383 the string if trailing spaces are significant. */
385 is_trim_ok (st_parameter_dt *dtp)
387 /* Check rank and stride. */
388 if (dtp->internal_unit_desc
389 && (GFC_DESCRIPTOR_RANK (dtp->internal_unit_desc) > 1
390 || GFC_DESCRIPTOR_STRIDE(dtp->internal_unit_desc, 0) != 1))
392 /* Format strings can not have 'BZ' or '/'. */
393 if (dtp->common.flags & IOPARM_DT_HAS_FORMAT)
395 char *p = dtp->format;
397 if (dtp->common.flags & IOPARM_DT_HAS_BLANK)
399 for (i = 0; i < dtp->format_len; i++)
401 if (p[i] == '/') return false;
402 if (p[i] == 'b' || p[i] == 'B')
403 if (p[i+1] == 'z' || p[i+1] == 'Z')
407 if (dtp->u.p.ionml) /* A namelist. */
414 get_internal_unit (st_parameter_dt *dtp)
417 gfc_offset start_record = 0;
419 /* Allocate memory for a unit structure. */
421 iunit = get_mem (sizeof (gfc_unit));
424 generate_error (&dtp->common, LIBERROR_INTERNAL_UNIT, NULL);
428 memset (iunit, '\0', sizeof (gfc_unit));
429 #ifdef __GTHREAD_MUTEX_INIT
431 __gthread_mutex_t tmp = __GTHREAD_MUTEX_INIT;
435 __GTHREAD_MUTEX_INIT_FUNCTION (&iunit->lock);
437 __gthread_mutex_lock (&iunit->lock);
439 iunit->recl = dtp->internal_unit_len;
441 /* For internal units we set the unit number to -1.
442 Otherwise internal units can be mistaken for a pre-connected unit or
443 some other file I/O unit. */
444 iunit->unit_number = -1;
446 /* As an optimization, adjust the unit record length to not
447 include trailing blanks. This will not work under certain conditions
448 where trailing blanks have significance. */
449 if (dtp->u.p.mode == READING && is_trim_ok (dtp))
452 if (dtp->common.unit == 0)
453 len = string_len_trim (dtp->internal_unit_len,
456 len = string_len_trim_char4 (dtp->internal_unit_len,
457 (const gfc_char4_t*) dtp->internal_unit);
458 dtp->internal_unit_len = len;
459 iunit->recl = dtp->internal_unit_len;
462 /* Set up the looping specification from the array descriptor, if any. */
464 if (is_array_io (dtp))
466 iunit->rank = GFC_DESCRIPTOR_RANK (dtp->internal_unit_desc);
467 iunit->ls = (array_loop_spec *)
468 get_mem (iunit->rank * sizeof (array_loop_spec));
469 dtp->internal_unit_len *=
470 init_loop_spec (dtp->internal_unit_desc, iunit->ls, &start_record);
472 start_record *= iunit->recl;
475 /* Set initial values for unit parameters. */
476 if (dtp->common.unit)
478 iunit->s = open_internal4 (dtp->internal_unit - start_record,
479 dtp->internal_unit_len, -start_record);
480 fbuf_init (iunit, 256);
483 iunit->s = open_internal (dtp->internal_unit - start_record,
484 dtp->internal_unit_len, -start_record);
486 iunit->bytes_left = iunit->recl;
487 iunit->last_record=0;
489 iunit->current_record=0;
491 iunit->endfile = NO_ENDFILE;
493 /* Set flags for the internal unit. */
495 iunit->flags.access = ACCESS_SEQUENTIAL;
496 iunit->flags.action = ACTION_READWRITE;
497 iunit->flags.blank = BLANK_NULL;
498 iunit->flags.form = FORM_FORMATTED;
499 iunit->flags.pad = PAD_YES;
500 iunit->flags.status = STATUS_UNSPECIFIED;
501 iunit->flags.sign = SIGN_SUPPRESS;
502 iunit->flags.decimal = DECIMAL_POINT;
503 iunit->flags.encoding = ENCODING_DEFAULT;
504 iunit->flags.async = ASYNC_NO;
505 iunit->flags.round = ROUND_COMPATIBLE;
507 /* Initialize the data transfer parameters. */
509 dtp->u.p.advance_status = ADVANCE_YES;
510 dtp->u.p.seen_dollar = 0;
512 dtp->u.p.pending_spaces = 0;
513 dtp->u.p.max_pos = 0;
516 /* This flag tells us the unit is assigned to internal I/O. */
518 dtp->u.p.unit_is_internal = 1;
524 /* free_internal_unit()-- Free memory allocated for internal units if any. */
526 free_internal_unit (st_parameter_dt *dtp)
528 if (!is_internal_unit (dtp))
531 if (unlikely (is_char4_unit (dtp)))
532 fbuf_destroy (dtp->u.p.current_unit);
534 if (dtp->u.p.current_unit != NULL)
536 free (dtp->u.p.current_unit->ls);
538 free (dtp->u.p.current_unit->s);
540 destroy_unit_mutex (dtp->u.p.current_unit);
546 /* get_unit()-- Returns the unit structure associated with the integer
547 unit or the internal file. */
550 get_unit (st_parameter_dt *dtp, int do_create)
553 if ((dtp->common.flags & IOPARM_DT_HAS_INTERNAL_UNIT) != 0)
554 return get_internal_unit (dtp);
556 /* Has to be an external unit. */
558 dtp->u.p.unit_is_internal = 0;
559 dtp->internal_unit_desc = NULL;
561 return get_external_unit (dtp->common.unit, do_create);
565 /*************************/
566 /* Initialize everything. */
574 #ifndef __GTHREAD_MUTEX_INIT
575 __GTHREAD_MUTEX_INIT_FUNCTION (&unit_lock);
578 if (options.stdin_unit >= 0)
580 u = insert_unit (options.stdin_unit);
581 u->s = input_stream ();
583 u->flags.action = ACTION_READ;
585 u->flags.access = ACCESS_SEQUENTIAL;
586 u->flags.form = FORM_FORMATTED;
587 u->flags.status = STATUS_OLD;
588 u->flags.blank = BLANK_NULL;
589 u->flags.pad = PAD_YES;
590 u->flags.position = POSITION_ASIS;
591 u->flags.sign = SIGN_SUPPRESS;
592 u->flags.decimal = DECIMAL_POINT;
593 u->flags.encoding = ENCODING_DEFAULT;
594 u->flags.async = ASYNC_NO;
595 u->flags.round = ROUND_COMPATIBLE;
597 u->recl = options.default_recl;
598 u->endfile = NO_ENDFILE;
600 u->file_len = strlen (stdin_name);
601 u->file = get_mem (u->file_len);
602 memmove (u->file, stdin_name, u->file_len);
606 __gthread_mutex_unlock (&u->lock);
609 if (options.stdout_unit >= 0)
611 u = insert_unit (options.stdout_unit);
612 u->s = output_stream ();
614 u->flags.action = ACTION_WRITE;
616 u->flags.access = ACCESS_SEQUENTIAL;
617 u->flags.form = FORM_FORMATTED;
618 u->flags.status = STATUS_OLD;
619 u->flags.blank = BLANK_NULL;
620 u->flags.position = POSITION_ASIS;
621 u->flags.sign = SIGN_SUPPRESS;
622 u->flags.decimal = DECIMAL_POINT;
623 u->flags.encoding = ENCODING_DEFAULT;
624 u->flags.async = ASYNC_NO;
625 u->flags.round = ROUND_COMPATIBLE;
627 u->recl = options.default_recl;
628 u->endfile = AT_ENDFILE;
630 u->file_len = strlen (stdout_name);
631 u->file = get_mem (u->file_len);
632 memmove (u->file, stdout_name, u->file_len);
636 __gthread_mutex_unlock (&u->lock);
639 if (options.stderr_unit >= 0)
641 u = insert_unit (options.stderr_unit);
642 u->s = error_stream ();
644 u->flags.action = ACTION_WRITE;
646 u->flags.access = ACCESS_SEQUENTIAL;
647 u->flags.form = FORM_FORMATTED;
648 u->flags.status = STATUS_OLD;
649 u->flags.blank = BLANK_NULL;
650 u->flags.position = POSITION_ASIS;
651 u->flags.sign = SIGN_SUPPRESS;
652 u->flags.decimal = DECIMAL_POINT;
653 u->flags.encoding = ENCODING_DEFAULT;
654 u->flags.async = ASYNC_NO;
655 u->flags.round = ROUND_COMPATIBLE;
657 u->recl = options.default_recl;
658 u->endfile = AT_ENDFILE;
660 u->file_len = strlen (stderr_name);
661 u->file = get_mem (u->file_len);
662 memmove (u->file, stderr_name, u->file_len);
664 fbuf_init (u, 256); /* 256 bytes should be enough, probably not doing
665 any kind of exotic formatting to stderr. */
667 __gthread_mutex_unlock (&u->lock);
670 /* Calculate the maximum file offset in a portable manner.
671 max will be the largest signed number for the type gfc_offset.
672 set a 1 in the LSB and keep a running sum, stopping at MSB-1 bit. */
674 for (i = 0; i < sizeof (max_offset) * 8 - 1; i++)
675 max_offset = max_offset + ((gfc_offset) 1 << i);
680 close_unit_1 (gfc_unit *u, int locked)
684 /* If there are previously written bytes from a write with ADVANCE="no"
685 Reposition the buffer before closing. */
686 if (u->previous_nonadvancing_write)
687 finish_last_advance_record (u);
689 rc = (u->s == NULL) ? 0 : sclose (u->s) == -1;
693 __gthread_mutex_lock (&unit_lock);
695 for (i = 0; i < CACHE_SIZE; i++)
696 if (unit_cache[i] == u)
697 unit_cache[i] = NULL;
705 free_format_hash_table (u);
709 __gthread_mutex_unlock (&u->lock);
711 /* If there are any threads waiting in find_unit for this unit,
712 avoid freeing the memory, the last such thread will free it
715 destroy_unit_mutex (u);
718 __gthread_mutex_unlock (&unit_lock);
724 unlock_unit (gfc_unit *u)
726 __gthread_mutex_unlock (&u->lock);
729 /* close_unit()-- Close a unit. The stream is closed, and any memory
730 associated with the stream is freed. Returns nonzero on I/O error.
731 Should be called with the u->lock locked. */
734 close_unit (gfc_unit *u)
736 return close_unit_1 (u, 0);
740 /* close_units()-- Delete units on completion. We just keep deleting
741 the root of the treap until there is nothing left.
742 Not sure what to do with locking here. Some other thread might be
743 holding some unit's lock and perhaps hold it indefinitely
744 (e.g. waiting for input from some pipe) and close_units shouldn't
745 delay the program too much. */
750 __gthread_mutex_lock (&unit_lock);
751 while (unit_root != NULL)
752 close_unit_1 (unit_root, 1);
753 __gthread_mutex_unlock (&unit_lock);
757 /* High level interface to truncate a file, i.e. flush format buffers,
758 and generate an error or set some flags. Just like POSIX
759 ftruncate, returns 0 on success, -1 on failure. */
762 unit_truncate (gfc_unit * u, gfc_offset pos, st_parameter_common * common)
766 /* Make sure format buffer is flushed. */
767 if (u->flags.form == FORM_FORMATTED)
769 if (u->mode == READING)
770 pos += fbuf_reset (u);
772 fbuf_flush (u, u->mode);
775 /* struncate() should flush the stream buffer if necessary, so don't
776 bother calling sflush() here. */
777 ret = struncate (u->s, pos);
780 generate_error (common, LIBERROR_OS, NULL);
783 u->endfile = AT_ENDFILE;
784 u->flags.position = POSITION_APPEND;
791 /* filename_from_unit()-- If the unit_number exists, return a pointer to the
792 name of the associated file, otherwise return the empty string. The caller
793 must free memory allocated for the filename string. */
796 filename_from_unit (int n)
806 c = compare (n, u->unit_number);
815 /* Get the filename. */
818 filename = (char *) get_mem (u->file_len + 1);
819 unpack_filename (filename, u->file, u->file_len);
823 return (char *) NULL;
827 finish_last_advance_record (gfc_unit *u)
830 if (u->saved_pos > 0)
831 fbuf_seek (u, u->saved_pos, SEEK_CUR);
833 if (!(u->unit_number == options.stdout_unit
834 || u->unit_number == options.stderr_unit))
841 char *p = fbuf_alloc (u, len);
843 os_error ("Completing record after ADVANCE_NO failed");
850 fbuf_flush (u, u->mode);
853 /* Assign a negative number for NEWUNIT in OPEN statements. */
855 get_unique_unit_number (st_parameter_open *opp)
859 #ifdef HAVE_SYNC_FETCH_AND_ADD
860 num = __sync_fetch_and_add (&next_available_newunit, -1);
862 __gthread_mutex_lock (&unit_lock);
863 num = next_available_newunit--;
864 __gthread_mutex_unlock (&unit_lock);
867 /* Do not allow NEWUNIT numbers to wrap. */
868 if (num > GFC_FIRST_NEWUNIT)
870 generate_error (&opp->common, LIBERROR_INTERNAL, "NEWUNIT exhausted");