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 #include "streams_mmap.h"
28 #include "streams_common.h"
29
30 /*
31 * Single-byte character memory map-based streams implementation
32 */
33
34 static int
stream_mmap_prime(stream_t * str)35 stream_mmap_prime(stream_t *str)
36 {
37 char *nl;
38
39 if (stream_is_primed(str))
40 return (PRIME_SUCCEEDED);
41
42 stream_set(str, STREAM_PRIMED);
43
44 if (str->s_buffer_size == 0) {
45 stream_set(str, STREAM_EOS_REACHED);
46 return (PRIME_FAILED_EMPTY_FILE);
47 }
48
49 str->s_current.l_data.sp = str->s_buffer;
50 str->s_type.SF.s_release_origin = str->s_buffer;
51 if ((nl = (char *)memchr(str->s_buffer, '\n', str->s_buffer_size)) ==
52 NULL) {
53 warn(WMSG_NEWLINE_ADDED, str->s_filename);
54 str->s_current.l_data_length = str->s_buffer_size;
55 } else {
56 str->s_current.l_data_length = nl - (char *)str->s_buffer;
57 }
58
59 str->s_current.l_collate.sp = NULL;
60 str->s_current.l_collate_length = 0;
61
62 __S(stats_incr_fetches());
63 return (PRIME_SUCCEEDED);
64 }
65
66 /*
67 * stream_mmap_fetch() sets the fields of str->s_current to delimit the next
68 * line of the field.
69 */
70 static ssize_t
stream_mmap_fetch(stream_t * str)71 stream_mmap_fetch(stream_t *str)
72 {
73 ssize_t dist_to_buf_end;
74 char *next_nl;
75
76 ASSERT(stream_is_primed(str));
77 ASSERT((str->s_status & STREAM_EOS_REACHED) == 0);
78
79 /*
80 * adding one for newline
81 */
82 str->s_current.l_data.sp = str->s_current.l_data.sp +
83 str->s_current.l_data_length + 1;
84
85 dist_to_buf_end = str->s_buffer_size - (str->s_current.l_data.sp
86 - (char *)str->s_buffer);
87 ASSERT(dist_to_buf_end >= 0 && dist_to_buf_end <= str->s_buffer_size);
88
89 next_nl = memchr(str->s_current.l_data.sp, '\n', dist_to_buf_end);
90
91 if (next_nl)
92 str->s_current.l_data_length = next_nl
93 - str->s_current.l_data.sp;
94 else {
95 warn(WMSG_NEWLINE_ADDED, str->s_filename);
96 str->s_current.l_data_length = dist_to_buf_end;
97 }
98
99 /*
100 * adding one for newline
101 */
102 if (str->s_current.l_data.sp + str->s_current.l_data_length + 1 >=
103 (char *)str->s_buffer + str->s_buffer_size)
104 stream_set(str, STREAM_EOS_REACHED);
105
106 str->s_current.l_collate_length = 0;
107
108 __S(stats_incr_fetches());
109 return (NEXT_LINE_COMPLETE);
110 }
111
112 static int
stream_mmap_is_closable(stream_t * str)113 stream_mmap_is_closable(stream_t *str)
114 {
115 if (str->s_status & STREAM_OPEN)
116 return (1);
117 return (0);
118 }
119
120 static int
stream_mmap_close(stream_t * str)121 stream_mmap_close(stream_t *str)
122 {
123 if (str->s_type.SF.s_fd > -1) {
124 (void) close(str->s_type.SF.s_fd);
125 stream_unset(str, STREAM_OPEN);
126 return (1);
127 }
128
129 return (0);
130 }
131
132 static int
stream_mmap_free(stream_t * str)133 stream_mmap_free(stream_t *str)
134 {
135 if (!(str->s_status & STREAM_OPEN) ||
136 (str->s_consumer != NULL &&
137 str->s_consumer->s_status & STREAM_NOT_FREEABLE))
138 return (0);
139
140 if (str->s_buffer == NULL)
141 return (1);
142
143 if (munmap(str->s_buffer, str->s_buffer_size) < 0)
144 die(EMSG_MUNMAP, str->s_filename);
145
146 str->s_buffer = NULL;
147 str->s_buffer_size = 0;
148
149 stream_unset(str, STREAM_PRIMED);
150
151 return (1);
152 }
153
154 static int
stream_mmap_eos(stream_t * str)155 stream_mmap_eos(stream_t *str)
156 {
157 int retval = 0;
158
159 if (str == NULL || str->s_status & STREAM_EOS_REACHED)
160 return (1);
161
162 /*
163 * If the file's size is known to be zero, then we are at EOS; the
164 * remaining checks are only sensible if we successfully primed this
165 * stream. The additional character is for the optional newline.
166 */
167 if (str->s_filesize == 0 ||
168 (stream_is_primed(str) && str->s_current.l_data.sp -
169 (char *)str->s_buffer + str->s_current.l_data_length + 1 >=
170 str->s_buffer_size)) {
171 retval = 1;
172 stream_set(str, STREAM_EOS_REACHED);
173 }
174
175 return (retval);
176 }
177
178 #define ALIGNED (~(ulong_t)(PAGESIZE - 1))
179
180 /*
181 * In certain cases, we know that we will never need the data on a page again
182 * for the duration of the sort. (These cases are associated with merges
183 * involving temporary files.) We can thus release all pages previous to the
184 * page containing the current line, using the MADV_DONTNEED flag to
185 * madvise(3C). This additional memory management improves our chances of
186 * avoiding a paging situation, by evicting pages we know are of no use.
187 */
188 static void
stream_mmap_release_line(stream_t * str)189 stream_mmap_release_line(stream_t *str)
190 {
191 caddr_t origin = str->s_type.SF.s_release_origin;
192 size_t release = 0;
193
194 while ((caddr_t)((ulong_t)str->s_current.l_data.sp & ALIGNED) -
195 (origin + release) >= DEFAULT_RELEASE_SIZE)
196 release += DEFAULT_RELEASE_SIZE;
197
198 if (release == 0)
199 return;
200
201 if (madvise(origin, release, MADV_DONTNEED) == -1)
202 warn(gettext("madvise failed"));
203
204 str->s_type.SF.s_release_origin += release;
205 }
206
207 const stream_ops_t stream_mmap_ops = {
208 stream_mmap_is_closable,
209 stream_mmap_close,
210 stream_mmap_eos,
211 stream_mmap_fetch,
212 NULL,
213 stream_mmap_free,
214 NULL,
215 stream_mmap_prime,
216 NULL,
217 stream_mmap_release_line,
218 NULL,
219 stream_stdio_unlink
220 };
221