ewah_read_mmap: bounds-check mmap reads
[git/git.git] / ewah / ewah_io.c
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1/**
2 * Copyright 2013, GitHub, Inc
3 * Copyright 2009-2013, Daniel Lemire, Cliff Moon,
4 * David McIntosh, Robert Becho, Google Inc. and Veronika Zenz
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version 2
9 * of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
48425792 17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
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18 */
19#include "git-compat-util.h"
20#include "ewok.h"
be0d9d53 21#include "strbuf.h"
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22
23int ewah_serialize_native(struct ewah_bitmap *self, int fd)
24{
25 uint32_t write32;
26 size_t to_write = self->buffer_size * 8;
27
28 /* 32 bit -- bit size for the map */
29 write32 = (uint32_t)self->bit_size;
30 if (write(fd, &write32, 4) != 4)
31 return -1;
32
33 /** 32 bit -- number of compressed 64-bit words */
34 write32 = (uint32_t)self->buffer_size;
35 if (write(fd, &write32, 4) != 4)
36 return -1;
37
38 if (write(fd, self->buffer, to_write) != to_write)
39 return -1;
40
41 /** 32 bit -- position for the RLW */
42 write32 = self->rlw - self->buffer;
43 if (write(fd, &write32, 4) != 4)
44 return -1;
45
46 return (3 * 4) + to_write;
47}
48
49int ewah_serialize_to(struct ewah_bitmap *self,
50 int (*write_fun)(void *, const void *, size_t),
51 void *data)
52{
53 size_t i;
54 eword_t dump[2048];
55 const size_t words_per_dump = sizeof(dump) / sizeof(eword_t);
56 uint32_t bitsize, word_count, rlw_pos;
57
58 const eword_t *buffer;
59 size_t words_left;
60
61 /* 32 bit -- bit size for the map */
62 bitsize = htonl((uint32_t)self->bit_size);
63 if (write_fun(data, &bitsize, 4) != 4)
64 return -1;
65
66 /** 32 bit -- number of compressed 64-bit words */
67 word_count = htonl((uint32_t)self->buffer_size);
68 if (write_fun(data, &word_count, 4) != 4)
69 return -1;
70
71 /** 64 bit x N -- compressed words */
72 buffer = self->buffer;
73 words_left = self->buffer_size;
74
75 while (words_left >= words_per_dump) {
76 for (i = 0; i < words_per_dump; ++i, ++buffer)
77 dump[i] = htonll(*buffer);
78
79 if (write_fun(data, dump, sizeof(dump)) != sizeof(dump))
80 return -1;
81
82 words_left -= words_per_dump;
83 }
84
85 if (words_left) {
86 for (i = 0; i < words_left; ++i, ++buffer)
87 dump[i] = htonll(*buffer);
88
89 if (write_fun(data, dump, words_left * 8) != words_left * 8)
90 return -1;
91 }
92
93 /** 32 bit -- position for the RLW */
94 rlw_pos = (uint8_t*)self->rlw - (uint8_t *)self->buffer;
95 rlw_pos = htonl(rlw_pos / sizeof(eword_t));
96
97 if (write_fun(data, &rlw_pos, 4) != 4)
98 return -1;
99
100 return (3 * 4) + (self->buffer_size * 8);
101}
102
103static int write_helper(void *fd, const void *buf, size_t len)
104{
105 return write((intptr_t)fd, buf, len);
106}
107
108int ewah_serialize(struct ewah_bitmap *self, int fd)
109{
110 return ewah_serialize_to(self, write_helper, (void *)(intptr_t)fd);
111}
112
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113static int write_strbuf(void *user_data, const void *data, size_t len)
114{
115 struct strbuf *sb = user_data;
116 strbuf_add(sb, data, len);
117 return len;
118}
119
120int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *sb)
121{
122 return ewah_serialize_to(self, write_strbuf, sb);
123}
124
9d2e330b 125ssize_t ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
e1273106 126{
a0a2f7d7 127 const uint8_t *ptr = map;
9d2e330b 128 size_t data_len;
6b5b3a27 129 size_t i;
a201c20b 130
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131 if (len < sizeof(uint32_t))
132 return error("corrupt ewah bitmap: eof before bit size");
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133 self->bit_size = get_be32(ptr);
134 ptr += sizeof(uint32_t);
9d2e330b 135 len -= sizeof(uint32_t);
a201c20b 136
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137 if (len < sizeof(uint32_t))
138 return error("corrupt ewah bitmap: eof before length");
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139 self->buffer_size = self->alloc_size = get_be32(ptr);
140 ptr += sizeof(uint32_t);
9d2e330b 141 len -= sizeof(uint32_t);
e1273106 142
08c95df8 143 REALLOC_ARRAY(self->buffer, self->alloc_size);
e1273106 144
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145 /*
146 * Copy the raw data for the bitmap as a whole chunk;
147 * if we're in a little-endian platform, we'll perform
148 * the endianness conversion in a separate pass to ensure
149 * we're loading 8-byte aligned words.
150 */
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151 data_len = st_mult(self->buffer_size, sizeof(eword_t));
152 if (len < data_len)
153 return error("corrupt ewah bitmap: eof in data "
154 "(%"PRIuMAX" bytes short)",
155 (uintmax_t)(data_len - len));
156 memcpy(self->buffer, ptr, data_len);
157 ptr += data_len;
158 len -= data_len;
a201c20b 159
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160 for (i = 0; i < self->buffer_size; ++i)
161 self->buffer[i] = ntohll(self->buffer[i]);
e1273106 162
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163 if (len < sizeof(uint32_t))
164 return error("corrupt ewah bitmap: eof before rlw");
a201c20b 165 self->rlw = self->buffer + get_be32(ptr);
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166 ptr += sizeof(uint32_t);
167 len -= sizeof(uint32_t);
e1273106 168
9d2e330b 169 return ptr - (const uint8_t *)map;
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170}
171
172int ewah_deserialize(struct ewah_bitmap *self, int fd)
173{
174 size_t i;
175 eword_t dump[2048];
176 const size_t words_per_dump = sizeof(dump) / sizeof(eword_t);
177 uint32_t bitsize, word_count, rlw_pos;
178
179 eword_t *buffer = NULL;
180 size_t words_left;
181
182 ewah_clear(self);
183
184 /* 32 bit -- bit size for the map */
185 if (read(fd, &bitsize, 4) != 4)
186 return -1;
187
188 self->bit_size = (size_t)ntohl(bitsize);
189
190 /** 32 bit -- number of compressed 64-bit words */
191 if (read(fd, &word_count, 4) != 4)
192 return -1;
193
194 self->buffer_size = self->alloc_size = (size_t)ntohl(word_count);
08c95df8 195 REALLOC_ARRAY(self->buffer, self->alloc_size);
e1273106 196
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197 /** 64 bit x N -- compressed words */
198 buffer = self->buffer;
199 words_left = self->buffer_size;
200
201 while (words_left >= words_per_dump) {
202 if (read(fd, dump, sizeof(dump)) != sizeof(dump))
203 return -1;
204
205 for (i = 0; i < words_per_dump; ++i, ++buffer)
206 *buffer = ntohll(dump[i]);
207
208 words_left -= words_per_dump;
209 }
210
211 if (words_left) {
212 if (read(fd, dump, words_left * 8) != words_left * 8)
213 return -1;
214
215 for (i = 0; i < words_left; ++i, ++buffer)
216 *buffer = ntohll(dump[i]);
217 }
218
219 /** 32 bit -- position for the RLW */
220 if (read(fd, &rlw_pos, 4) != 4)
221 return -1;
222
223 self->rlw = self->buffer + ntohl(rlw_pos);
224 return 0;
225}