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60084cf1 AG |
1 | /* |
2 | * libkmod - interface to kernel built-in modules | |
3 | * | |
4 | * Copyright (C) 2019 Alexey Gladkov <gladkov.alexey@gmail.com> | |
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 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include <sys/types.h> | |
21 | #include <sys/stat.h> | |
22 | ||
23 | #include <unistd.h> | |
24 | #include <stdio.h> | |
25 | #include <stdlib.h> | |
26 | #include <string.h> | |
27 | #include <errno.h> | |
28 | ||
29 | #include "libkmod.h" | |
30 | #include "libkmod-internal.h" | |
31 | ||
32 | #define MODULES_BUILTIN_MODINFO "modules.builtin.modinfo" | |
33 | ||
34 | struct kmod_builtin_iter { | |
35 | struct kmod_ctx *ctx; | |
36 | ||
37 | // The file descriptor. | |
38 | int file; | |
39 | ||
40 | // The total size in bytes. | |
41 | ssize_t size; | |
42 | ||
43 | // The offset of current module. | |
44 | off_t pos; | |
45 | ||
46 | // The offset at which the next module is located. | |
47 | off_t next; | |
48 | ||
49 | // Number of strings in the current block. | |
50 | ssize_t nstrings; | |
51 | ||
52 | // Internal buffer and its size. | |
53 | size_t bufsz; | |
54 | char *buf; | |
55 | }; | |
56 | ||
57 | struct kmod_builtin_iter *kmod_builtin_iter_new(struct kmod_ctx *ctx) | |
58 | { | |
59 | char path[PATH_MAX]; | |
60 | int file, sv_errno; | |
61 | struct stat sb; | |
62 | struct kmod_builtin_iter *iter = NULL; | |
63 | const char *dirname = kmod_get_dirname(ctx); | |
64 | size_t len = strlen(dirname); | |
65 | ||
66 | file = -1; | |
67 | ||
68 | if ((len + 1 + strlen(MODULES_BUILTIN_MODINFO) + 1) >= PATH_MAX) { | |
69 | sv_errno = ENAMETOOLONG; | |
70 | goto fail; | |
71 | } | |
72 | ||
73 | snprintf(path, PATH_MAX, "%s/%s", dirname, MODULES_BUILTIN_MODINFO); | |
74 | ||
75 | file = open(path, O_RDONLY|O_CLOEXEC); | |
76 | if (file < 0) { | |
77 | sv_errno = errno; | |
78 | goto fail; | |
79 | } | |
80 | ||
81 | if (fstat(file, &sb) < 0) { | |
82 | sv_errno = errno; | |
83 | goto fail; | |
84 | } | |
85 | ||
86 | iter = malloc(sizeof(*iter)); | |
87 | if (!iter) { | |
88 | sv_errno = ENOMEM; | |
89 | goto fail; | |
90 | } | |
91 | ||
92 | iter->ctx = ctx; | |
93 | iter->file = file; | |
94 | iter->size = sb.st_size; | |
95 | iter->nstrings = 0; | |
96 | iter->pos = 0; | |
97 | iter->next = 0; | |
98 | iter->bufsz = 0; | |
99 | iter->buf = NULL; | |
100 | ||
101 | return iter; | |
102 | fail: | |
103 | if (file >= 0) | |
104 | close(file); | |
105 | ||
106 | errno = sv_errno; | |
107 | ||
108 | return iter; | |
109 | } | |
110 | ||
111 | void kmod_builtin_iter_free(struct kmod_builtin_iter *iter) | |
112 | { | |
113 | close(iter->file); | |
114 | free(iter->buf); | |
115 | free(iter); | |
116 | } | |
117 | ||
118 | static off_t get_string(struct kmod_builtin_iter *iter, off_t offset, | |
119 | char **line, size_t *size) | |
120 | { | |
121 | int sv_errno; | |
122 | char *nullp = NULL; | |
123 | size_t linesz = 0; | |
124 | ||
125 | while (!nullp) { | |
126 | char buf[BUFSIZ]; | |
127 | ssize_t sz; | |
128 | size_t partsz; | |
129 | ||
130 | sz = pread(iter->file, buf, BUFSIZ, offset); | |
131 | if (sz < 0) { | |
132 | sv_errno = errno; | |
133 | goto fail; | |
134 | } else if (sz == 0) { | |
135 | offset = 0; | |
136 | break; | |
137 | } | |
138 | ||
139 | nullp = memchr(buf, '\0', (size_t) sz); | |
140 | partsz = (size_t)((nullp) ? (nullp - buf) + 1 : sz); | |
141 | offset += (off_t) partsz; | |
142 | ||
143 | if (iter->bufsz < linesz + partsz) { | |
144 | iter->bufsz = linesz + partsz; | |
145 | iter->buf = realloc(iter->buf, iter->bufsz); | |
146 | ||
147 | if (!iter->buf) { | |
148 | sv_errno = errno; | |
149 | goto fail; | |
150 | } | |
151 | } | |
152 | ||
153 | strncpy(iter->buf + linesz, buf, partsz); | |
154 | linesz += partsz; | |
155 | } | |
156 | ||
157 | if (linesz) { | |
158 | *line = iter->buf; | |
159 | *size = linesz; | |
160 | } | |
161 | ||
162 | return offset; | |
163 | fail: | |
164 | errno = sv_errno; | |
165 | return -1; | |
166 | } | |
167 | ||
168 | bool kmod_builtin_iter_next(struct kmod_builtin_iter *iter) | |
169 | { | |
170 | char *line, *modname; | |
171 | size_t linesz; | |
172 | off_t pos, offset, modlen; | |
173 | ||
174 | modname = NULL; | |
175 | ||
176 | iter->nstrings = 0; | |
177 | offset = pos = iter->next; | |
178 | ||
179 | while (offset < iter->size) { | |
180 | char *dot; | |
181 | off_t len; | |
182 | ||
183 | offset = get_string(iter, pos, &line, &linesz); | |
184 | if (offset <= 0) { | |
185 | if (offset) | |
186 | ERR(iter->ctx, "get_string: %s\n", strerror(errno)); | |
187 | pos = iter->size; | |
188 | break; | |
189 | } | |
190 | ||
191 | dot = strchr(line, '.'); | |
192 | if (!dot) { | |
193 | ERR(iter->ctx, "kmod_builtin_iter_next: unexpected string without modname prefix\n"); | |
194 | pos = iter->size; | |
195 | break; | |
196 | } | |
197 | ||
198 | len = dot - line; | |
199 | ||
200 | if (!modname) { | |
201 | modname = strdup(line); | |
202 | modlen = len; | |
203 | } else if (modlen != len || strncmp(modname, line, len)) { | |
204 | break; | |
205 | } | |
206 | ||
207 | iter->nstrings++; | |
208 | pos = offset; | |
209 | } | |
210 | ||
211 | iter->pos = iter->next; | |
212 | iter->next = pos; | |
213 | ||
214 | free(modname); | |
215 | ||
216 | return (iter->pos < iter->size); | |
217 | } | |
218 | ||
219 | bool kmod_builtin_iter_get_modname(struct kmod_builtin_iter *iter, | |
220 | char modname[static PATH_MAX]) | |
221 | { | |
222 | int sv_errno; | |
223 | char *line, *dot; | |
224 | size_t linesz, len; | |
225 | off_t offset; | |
226 | ||
227 | if (iter->pos == iter->size) | |
228 | return false; | |
229 | ||
230 | line = NULL; | |
231 | ||
232 | offset = get_string(iter, iter->pos, &line, &linesz); | |
233 | if (offset <= 0) { | |
234 | sv_errno = errno; | |
235 | if (offset) | |
236 | ERR(iter->ctx, "get_string: %s\n", strerror(errno)); | |
237 | goto fail; | |
238 | } | |
239 | ||
240 | dot = strchr(line, '.'); | |
241 | if (!dot) { | |
242 | sv_errno = errno; | |
243 | ERR(iter->ctx, "kmod_builtin_iter_get_modname: unexpected string without modname prefix\n"); | |
244 | goto fail; | |
245 | } | |
246 | ||
247 | len = dot - line; | |
248 | ||
249 | if (len > PATH_MAX) { | |
250 | sv_errno = ENAMETOOLONG; | |
251 | goto fail; | |
252 | } | |
253 | ||
254 | strncpy(modname, line, len); | |
255 | modname[len] = '\0'; | |
256 | ||
257 | return true; | |
258 | fail: | |
259 | errno = sv_errno; | |
260 | return false; | |
261 | } | |
262 | ||
263 | /* array will be allocated with strings in a single malloc, just free *array */ | |
264 | ssize_t kmod_builtin_get_modinfo(struct kmod_ctx *ctx, const char *modname, | |
265 | char ***modinfo) | |
266 | { | |
267 | ssize_t count = 0; | |
268 | char *s, *line = NULL; | |
269 | size_t i, n, linesz, modlen, size; | |
270 | off_t pos, offset; | |
271 | ||
272 | char *name = NULL; | |
273 | char buf[PATH_MAX]; | |
274 | ||
275 | struct kmod_builtin_iter *iter = kmod_builtin_iter_new(ctx); | |
276 | ||
277 | if (!iter) | |
278 | return -1; | |
279 | ||
280 | while (!name && kmod_builtin_iter_next(iter)) { | |
281 | if (!kmod_builtin_iter_get_modname(iter, buf)) { | |
282 | count = -errno; | |
283 | goto fail; | |
284 | } | |
285 | ||
286 | if (strcmp(modname, buf)) | |
287 | continue; | |
288 | ||
289 | name = buf; | |
290 | } | |
291 | ||
292 | if (!name) { | |
293 | count = -ENOSYS; | |
294 | goto fail; | |
295 | } | |
296 | ||
297 | modlen = strlen(modname) + 1; | |
298 | count = iter->nstrings; | |
299 | size = iter->next - iter->pos - (modlen * count); | |
300 | ||
301 | *modinfo = malloc(size + sizeof(char *) * (count + 1)); | |
302 | if (!*modinfo) { | |
303 | count = -errno; | |
304 | goto fail; | |
305 | } | |
306 | ||
307 | s = (char *)(*modinfo + count + 1); | |
308 | i = 0; | |
309 | ||
310 | n = 0; | |
311 | offset = pos = iter->pos; | |
312 | ||
313 | while (offset < iter->next) { | |
314 | offset = get_string(iter, pos, &line, &linesz); | |
315 | if (offset <= 0) { | |
316 | count = (offset) ? -errno : -EOF; | |
317 | goto fail; | |
318 | } | |
319 | ||
320 | strcpy(s + i, line + modlen); | |
321 | (*modinfo)[n++] = s + i; | |
322 | i += linesz - modlen; | |
323 | ||
324 | pos = offset; | |
325 | } | |
326 | fail: | |
327 | kmod_builtin_iter_free(iter); | |
328 | return count; | |
329 | } |