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1 | /* | |
2 | libloc - A library to determine the location of someone on the Internet | |
3 | ||
4 | Copyright (C) 2017 IPFire Development Team <info@ipfire.org> | |
5 | ||
6 | This library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Lesser General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
10 | ||
11 | This library 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 GNU | |
14 | Lesser General Public License for more details. | |
15 | */ | |
16 | ||
17 | #include <errno.h> | |
18 | #include <stddef.h> | |
19 | #include <stdio.h> | |
20 | #include <stdlib.h> | |
21 | #include <string.h> | |
22 | #include <sys/mman.h> | |
23 | #include <unistd.h> | |
24 | ||
25 | #include <loc/libloc.h> | |
26 | #include <loc/format.h> | |
27 | #include <loc/private.h> | |
28 | #include <loc/stringpool.h> | |
29 | ||
30 | enum loc_stringpool_mode { | |
31 | STRINGPOOL_DEFAULT, | |
32 | STRINGPOOL_MMAP, | |
33 | }; | |
34 | ||
35 | struct loc_stringpool { | |
36 | struct loc_ctx* ctx; | |
37 | int refcount; | |
38 | ||
39 | enum loc_stringpool_mode mode; | |
40 | ||
41 | char* data; | |
42 | ssize_t length; | |
43 | ||
44 | char* pos; | |
45 | }; | |
46 | ||
47 | static int __loc_stringpool_new(struct loc_ctx* ctx, struct loc_stringpool** pool, enum loc_stringpool_mode mode) { | |
48 | struct loc_stringpool* p = calloc(1, sizeof(*p)); | |
49 | if (!p) | |
50 | return -ENOMEM; | |
51 | ||
52 | p->ctx = loc_ref(ctx); | |
53 | p->refcount = 1; | |
54 | ||
55 | // Save mode | |
56 | p->mode = mode; | |
57 | ||
58 | *pool = p; | |
59 | ||
60 | return 0; | |
61 | } | |
62 | ||
63 | LOC_EXPORT int loc_stringpool_new(struct loc_ctx* ctx, struct loc_stringpool** pool) { | |
64 | return __loc_stringpool_new(ctx, pool, STRINGPOOL_DEFAULT); | |
65 | } | |
66 | ||
67 | static int loc_stringpool_mmap(struct loc_stringpool* pool, FILE* f, size_t length, off_t offset) { | |
68 | if (pool->mode != STRINGPOOL_MMAP) | |
69 | return -EINVAL; | |
70 | ||
71 | DEBUG(pool->ctx, "Reading string pool starting from %jd (%zu bytes)\n", (intmax_t)offset, length); | |
72 | ||
73 | // Map file content into memory | |
74 | pool->data = pool->pos = mmap(NULL, length, PROT_READ, | |
75 | MAP_PRIVATE, fileno(f), offset); | |
76 | ||
77 | // Store size of section | |
78 | pool->length = length; | |
79 | ||
80 | if (pool->data == MAP_FAILED) | |
81 | return -errno; | |
82 | ||
83 | return 0; | |
84 | } | |
85 | ||
86 | LOC_EXPORT int loc_stringpool_open(struct loc_ctx* ctx, struct loc_stringpool** pool, | |
87 | FILE* f, size_t length, off_t offset) { | |
88 | int r = __loc_stringpool_new(ctx, pool, STRINGPOOL_MMAP); | |
89 | if (r) | |
90 | return r; | |
91 | ||
92 | // Map data into memory | |
93 | if (length > 0) { | |
94 | r = loc_stringpool_mmap(*pool, f, length, offset); | |
95 | if (r) | |
96 | return r; | |
97 | } | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
102 | LOC_EXPORT struct loc_stringpool* loc_stringpool_ref(struct loc_stringpool* pool) { | |
103 | pool->refcount++; | |
104 | ||
105 | return pool; | |
106 | } | |
107 | ||
108 | static void loc_stringpool_free(struct loc_stringpool* pool) { | |
109 | DEBUG(pool->ctx, "Releasing string pool %p\n", pool); | |
110 | int r; | |
111 | ||
112 | switch (pool->mode) { | |
113 | case STRINGPOOL_DEFAULT: | |
114 | if (pool->data) | |
115 | free(pool->data); | |
116 | break; | |
117 | ||
118 | case STRINGPOOL_MMAP: | |
119 | if (pool->data) { | |
120 | r = munmap(pool->data, pool->length); | |
121 | if (r) | |
122 | ERROR(pool->ctx, "Could not unmap data at %p: %s\n", | |
123 | pool->data, strerror(errno)); | |
124 | } | |
125 | break; | |
126 | } | |
127 | ||
128 | loc_unref(pool->ctx); | |
129 | free(pool); | |
130 | } | |
131 | ||
132 | LOC_EXPORT struct loc_stringpool* loc_stringpool_unref(struct loc_stringpool* pool) { | |
133 | if (--pool->refcount > 0) | |
134 | return NULL; | |
135 | ||
136 | loc_stringpool_free(pool); | |
137 | ||
138 | return NULL; | |
139 | } | |
140 | ||
141 | static off_t loc_stringpool_get_offset(struct loc_stringpool* pool, const char* pos) { | |
142 | if (pos < pool->data) | |
143 | return -EFAULT; | |
144 | ||
145 | if (pos > (pool->data + pool->length)) | |
146 | return -EFAULT; | |
147 | ||
148 | return pos - pool->data; | |
149 | } | |
150 | ||
151 | static off_t loc_stringpool_get_next_offset(struct loc_stringpool* pool, off_t offset) { | |
152 | const char* string = loc_stringpool_get(pool, offset); | |
153 | ||
154 | return offset + strlen(string) + 1; | |
155 | } | |
156 | ||
157 | static char* __loc_stringpool_get(struct loc_stringpool* pool, off_t offset) { | |
158 | if (offset < 0 || offset >= pool->length) | |
159 | return NULL; | |
160 | ||
161 | return pool->data + offset; | |
162 | } | |
163 | ||
164 | LOC_EXPORT const char* loc_stringpool_get(struct loc_stringpool* pool, off_t offset) { | |
165 | return __loc_stringpool_get(pool, offset); | |
166 | } | |
167 | ||
168 | LOC_EXPORT size_t loc_stringpool_get_size(struct loc_stringpool* pool) { | |
169 | return loc_stringpool_get_offset(pool, pool->pos); | |
170 | } | |
171 | ||
172 | static off_t loc_stringpool_find(struct loc_stringpool* pool, const char* s) { | |
173 | if (!s || !*s) | |
174 | return -EINVAL; | |
175 | ||
176 | off_t offset = 0; | |
177 | while (offset < pool->length) { | |
178 | const char* string = loc_stringpool_get(pool, offset); | |
179 | if (!string) | |
180 | break; | |
181 | ||
182 | int r = strcmp(s, string); | |
183 | if (r == 0) | |
184 | return offset; | |
185 | ||
186 | offset = loc_stringpool_get_next_offset(pool, offset); | |
187 | } | |
188 | ||
189 | return -ENOENT; | |
190 | } | |
191 | ||
192 | static int loc_stringpool_grow(struct loc_stringpool* pool, size_t length) { | |
193 | DEBUG(pool->ctx, "Growing string pool to %zu bytes\n", length); | |
194 | ||
195 | // Save pos pointer | |
196 | off_t pos = loc_stringpool_get_offset(pool, pool->pos); | |
197 | ||
198 | // Reallocate data section | |
199 | pool->data = realloc(pool->data, length); | |
200 | if (!pool->data) | |
201 | return -ENOMEM; | |
202 | ||
203 | pool->length = length; | |
204 | ||
205 | // Restore pos | |
206 | pool->pos = __loc_stringpool_get(pool, pos); | |
207 | ||
208 | return 0; | |
209 | } | |
210 | ||
211 | static off_t loc_stringpool_append(struct loc_stringpool* pool, const char* string) { | |
212 | if (!string || !*string) | |
213 | return -EINVAL; | |
214 | ||
215 | DEBUG(pool->ctx, "Appending '%s' to string pool at %p\n", string, pool); | |
216 | ||
217 | // Make sure we have enough space | |
218 | int r = loc_stringpool_grow(pool, pool->length + strlen(string) + 1); | |
219 | if (r) { | |
220 | errno = r; | |
221 | return -1; | |
222 | } | |
223 | ||
224 | off_t offset = loc_stringpool_get_offset(pool, pool->pos); | |
225 | ||
226 | // Copy string byte by byte | |
227 | while (*string) | |
228 | *pool->pos++ = *string++; | |
229 | ||
230 | // Terminate the string | |
231 | *pool->pos++ = '\0'; | |
232 | ||
233 | return offset; | |
234 | } | |
235 | ||
236 | LOC_EXPORT off_t loc_stringpool_add(struct loc_stringpool* pool, const char* string) { | |
237 | off_t offset = loc_stringpool_find(pool, string); | |
238 | if (offset >= 0) { | |
239 | DEBUG(pool->ctx, "Found '%s' at position %jd\n", string, (intmax_t)offset); | |
240 | return offset; | |
241 | } | |
242 | ||
243 | return loc_stringpool_append(pool, string); | |
244 | } | |
245 | ||
246 | LOC_EXPORT void loc_stringpool_dump(struct loc_stringpool* pool) { | |
247 | off_t offset = 0; | |
248 | ||
249 | while (offset < pool->length) { | |
250 | const char* string = loc_stringpool_get(pool, offset); | |
251 | if (!string) | |
252 | break; | |
253 | ||
254 | printf("%jd (%zu): %s\n", (intmax_t)offset, strlen(string), string); | |
255 | ||
256 | offset = loc_stringpool_get_next_offset(pool, offset); | |
257 | } | |
258 | } | |
259 | ||
260 | LOC_EXPORT size_t loc_stringpool_write(struct loc_stringpool* pool, FILE* f) { | |
261 | size_t size = loc_stringpool_get_size(pool); | |
262 | ||
263 | return fwrite(pool->data, sizeof(*pool->data), size, f); | |
264 | } |