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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include "streams_mmap.h"
#include "streams_common.h"
/*
* Single-byte character memory map-based streams implementation
*/
static int
stream_mmap_prime(stream_t *str)
{
char *nl;
if (stream_is_primed(str))
return (PRIME_SUCCEEDED);
stream_set(str, STREAM_PRIMED);
if (str->s_buffer_size == 0) {
stream_set(str, STREAM_EOS_REACHED);
return (PRIME_FAILED_EMPTY_FILE);
}
str->s_current.l_data.sp = str->s_buffer;
str->s_type.SF.s_release_origin = str->s_buffer;
if ((nl = (char *)memchr(str->s_buffer, '\n', str->s_buffer_size)) ==
NULL) {
warn(WMSG_NEWLINE_ADDED, str->s_filename);
str->s_current.l_data_length = str->s_buffer_size;
} else {
str->s_current.l_data_length = nl - (char *)str->s_buffer;
}
str->s_current.l_collate.sp = NULL;
str->s_current.l_collate_length = 0;
__S(stats_incr_fetches());
return (PRIME_SUCCEEDED);
}
/*
* stream_mmap_fetch() sets the fields of str->s_current to delimit the next
* line of the field.
*/
static ssize_t
stream_mmap_fetch(stream_t *str)
{
ssize_t dist_to_buf_end;
char *next_nl;
ASSERT(stream_is_primed(str));
ASSERT((str->s_status & STREAM_EOS_REACHED) == 0);
/*
* adding one for newline
*/
str->s_current.l_data.sp = str->s_current.l_data.sp +
str->s_current.l_data_length + 1;
dist_to_buf_end = str->s_buffer_size - (str->s_current.l_data.sp
- (char *)str->s_buffer);
ASSERT(dist_to_buf_end >= 0 && dist_to_buf_end <= str->s_buffer_size);
next_nl = memchr(str->s_current.l_data.sp, '\n', dist_to_buf_end);
if (next_nl)
str->s_current.l_data_length = next_nl
- str->s_current.l_data.sp;
else {
warn(WMSG_NEWLINE_ADDED, str->s_filename);
str->s_current.l_data_length = dist_to_buf_end;
}
/*
* adding one for newline
*/
if (str->s_current.l_data.sp + str->s_current.l_data_length + 1 >=
(char *)str->s_buffer + str->s_buffer_size)
stream_set(str, STREAM_EOS_REACHED);
str->s_current.l_collate_length = 0;
__S(stats_incr_fetches());
return (NEXT_LINE_COMPLETE);
}
static int
stream_mmap_is_closable(stream_t *str)
{
if (str->s_status & STREAM_OPEN)
return (1);
return (0);
}
static int
stream_mmap_close(stream_t *str)
{
if (str->s_type.SF.s_fd > -1) {
(void) close(str->s_type.SF.s_fd);
stream_unset(str, STREAM_OPEN);
return (1);
}
return (0);
}
static int
stream_mmap_free(stream_t *str)
{
if (!(str->s_status & STREAM_OPEN) ||
(str->s_consumer != NULL &&
str->s_consumer->s_status & STREAM_NOT_FREEABLE))
return (0);
if (str->s_buffer == NULL)
return (1);
if (munmap(str->s_buffer, str->s_buffer_size) < 0)
die(EMSG_MUNMAP, str->s_filename);
str->s_buffer = NULL;
str->s_buffer_size = 0;
stream_unset(str, STREAM_PRIMED);
return (1);
}
static int
stream_mmap_eos(stream_t *str)
{
int retval = 0;
if (str == NULL || str->s_status & STREAM_EOS_REACHED)
return (1);
/*
* If the file's size is known to be zero, then we are at EOS; the
* remaining checks are only sensible if we successfully primed this
* stream. The additional character is for the optional newline.
*/
if (str->s_filesize == 0 ||
(stream_is_primed(str) && str->s_current.l_data.sp -
(char *)str->s_buffer + str->s_current.l_data_length + 1 >=
str->s_buffer_size)) {
retval = 1;
stream_set(str, STREAM_EOS_REACHED);
}
return (retval);
}
#define ALIGNED (~(ulong_t)(PAGESIZE - 1))
/*
* In certain cases, we know that we will never need the data on a page again
* for the duration of the sort. (These cases are associated with merges
* involving temporary files.) We can thus release all pages previous to the
* page containing the current line, using the MADV_DONTNEED flag to
* madvise(3C). This additional memory management improves our chances of
* avoiding a paging situation, by evicting pages we know are of no use.
*/
static void
stream_mmap_release_line(stream_t *str)
{
caddr_t origin = str->s_type.SF.s_release_origin;
size_t release = 0;
while ((caddr_t)((ulong_t)str->s_current.l_data.sp & ALIGNED) -
(origin + release) >= DEFAULT_RELEASE_SIZE)
release += DEFAULT_RELEASE_SIZE;
if (release == 0)
return;
if (madvise(origin, release, MADV_DONTNEED) == -1)
warn(gettext("madvise failed"));
str->s_type.SF.s_release_origin += release;
}
const stream_ops_t stream_mmap_ops = {
stream_mmap_is_closable,
stream_mmap_close,
stream_mmap_eos,
stream_mmap_fetch,
NULL,
stream_mmap_free,
NULL,
stream_mmap_prime,
NULL,
stream_mmap_release_line,
NULL,
stream_stdio_unlink
};
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