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