1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include "streams_mmap.h"
30 #include "streams_common.h"
31 
32 /*
33  * Single-byte character memory map-based streams implementation
34  */
35 
36 static int
stream_mmap_prime(stream_t * str)37 stream_mmap_prime(stream_t *str)
38 {
39 	char *nl;
40 
41 	if (stream_is_primed(str))
42 		return (PRIME_SUCCEEDED);
43 
44 	stream_set(str, STREAM_PRIMED);
45 
46 	if (str->s_buffer_size == 0) {
47 		stream_set(str, STREAM_EOS_REACHED);
48 		return (PRIME_FAILED_EMPTY_FILE);
49 	}
50 
51 	str->s_current.l_data.sp = str->s_buffer;
52 	str->s_type.SF.s_release_origin = str->s_buffer;
53 	if ((nl = (char *)memchr(str->s_buffer, '\n', str->s_buffer_size)) ==
54 	    NULL) {
55 		warn(WMSG_NEWLINE_ADDED, str->s_filename);
56 		str->s_current.l_data_length = str->s_buffer_size;
57 	} else {
58 		str->s_current.l_data_length = nl - (char *)str->s_buffer;
59 	}
60 
61 	str->s_current.l_collate.sp = NULL;
62 	str->s_current.l_collate_length = 0;
63 
64 	__S(stats_incr_fetches());
65 	return (PRIME_SUCCEEDED);
66 }
67 
68 /*
69  * stream_mmap_fetch() sets the fields of str->s_current to delimit the next
70  * line of the field.
71  */
72 static ssize_t
stream_mmap_fetch(stream_t * str)73 stream_mmap_fetch(stream_t *str)
74 {
75 	ssize_t dist_to_buf_end;
76 	char *next_nl;
77 
78 	ASSERT(stream_is_primed(str));
79 	ASSERT((str->s_status & STREAM_EOS_REACHED) == 0);
80 
81 	/*
82 	 * adding one for newline
83 	 */
84 	str->s_current.l_data.sp = str->s_current.l_data.sp +
85 	    str->s_current.l_data_length + 1;
86 
87 	dist_to_buf_end = str->s_buffer_size - (str->s_current.l_data.sp
88 	    - (char *)str->s_buffer);
89 	ASSERT(dist_to_buf_end >= 0 && dist_to_buf_end <= str->s_buffer_size);
90 
91 	next_nl = memchr(str->s_current.l_data.sp, '\n', dist_to_buf_end);
92 
93 	if (next_nl)
94 		str->s_current.l_data_length = next_nl
95 		    - str->s_current.l_data.sp;
96 	else {
97 		warn(WMSG_NEWLINE_ADDED, str->s_filename);
98 		str->s_current.l_data_length = dist_to_buf_end;
99 	}
100 
101 	/*
102 	 * adding one for newline
103 	 */
104 	if (str->s_current.l_data.sp + str->s_current.l_data_length + 1 >=
105 	    (char *)str->s_buffer + str->s_buffer_size)
106 		stream_set(str, STREAM_EOS_REACHED);
107 
108 	str->s_current.l_collate_length = 0;
109 
110 	__S(stats_incr_fetches());
111 	return (NEXT_LINE_COMPLETE);
112 }
113 
114 static int
stream_mmap_is_closable(stream_t * str)115 stream_mmap_is_closable(stream_t *str)
116 {
117 	if (str->s_status & STREAM_OPEN)
118 		return (1);
119 	return (0);
120 }
121 
122 static int
stream_mmap_close(stream_t * str)123 stream_mmap_close(stream_t *str)
124 {
125 	if (str->s_type.SF.s_fd > -1) {
126 		(void) close(str->s_type.SF.s_fd);
127 		stream_unset(str, STREAM_OPEN);
128 		return (1);
129 	}
130 
131 	return (0);
132 }
133 
134 static int
stream_mmap_free(stream_t * str)135 stream_mmap_free(stream_t *str)
136 {
137 	if (!(str->s_status & STREAM_OPEN) ||
138 	    (str->s_consumer != NULL &&
139 	    str->s_consumer->s_status & STREAM_NOT_FREEABLE))
140 		return (0);
141 
142 	if (str->s_buffer == NULL)
143 		return (1);
144 
145 	if (munmap(str->s_buffer, str->s_buffer_size) < 0)
146 		die(EMSG_MUNMAP, str->s_filename);
147 
148 	str->s_buffer = NULL;
149 	str->s_buffer_size = 0;
150 
151 	stream_unset(str, STREAM_PRIMED);
152 
153 	return (1);
154 }
155 
156 static int
stream_mmap_eos(stream_t * str)157 stream_mmap_eos(stream_t *str)
158 {
159 	int retval = 0;
160 
161 	if (str == NULL || str->s_status & STREAM_EOS_REACHED)
162 		return (1);
163 
164 	/*
165 	 * If the file's size is known to be zero, then we are at EOS; the
166 	 * remaining checks are only sensible if we successfully primed this
167 	 * stream.  The additional character is for the optional newline.
168 	 */
169 	if (str->s_filesize == 0 ||
170 	    (stream_is_primed(str) && str->s_current.l_data.sp -
171 	    (char *)str->s_buffer + str->s_current.l_data_length + 1 >=
172 	    str->s_buffer_size)) {
173 		retval = 1;
174 		stream_set(str, STREAM_EOS_REACHED);
175 	}
176 
177 	return (retval);
178 }
179 
180 #define	ALIGNED		(~(ulong_t)(PAGESIZE - 1))
181 
182 /*
183  * In certain cases, we know that we will never need the data on a page again
184  * for the duration of the sort.  (These cases are associated with merges
185  * involving temporary files.)  We can thus release all pages previous to the
186  * page containing the current line, using the MADV_DONTNEED flag to
187  * madvise(3C).  This additional memory management improves our chances of
188  * avoiding a paging situation, by evicting pages we know are of no use.
189  */
190 static void
stream_mmap_release_line(stream_t * str)191 stream_mmap_release_line(stream_t *str)
192 {
193 	caddr_t origin = str->s_type.SF.s_release_origin;
194 	size_t release = 0;
195 
196 	while ((caddr_t)((ulong_t)str->s_current.l_data.sp & ALIGNED) -
197 	    (origin + release) >= DEFAULT_RELEASE_SIZE)
198 		release += DEFAULT_RELEASE_SIZE;
199 
200 	if (release == 0)
201 		return;
202 
203 	if (madvise(origin, release, MADV_DONTNEED) == -1)
204 		warn(gettext("madvise failed"));
205 
206 	str->s_type.SF.s_release_origin += release;
207 }
208 
209 const stream_ops_t stream_mmap_ops = {
210 	stream_mmap_is_closable,
211 	stream_mmap_close,
212 	stream_mmap_eos,
213 	stream_mmap_fetch,
214 	NULL,
215 	stream_mmap_free,
216 	NULL,
217 	stream_mmap_prime,
218 	NULL,
219 	stream_mmap_release_line,
220 	NULL,
221 	stream_stdio_unlink
222 };
223