Use struct addr - big cleanup.
[darkstat] / db.c
1 /* darkstat 3
2 *
3 * db.c: load and save in-memory database from/to file
4 * copyright (c) 2007 Ben Stewart, Emil Mikulic.
5 *
6 * You may use, modify and redistribute this file under the terms of the
7 * GNU General Public License version 2. (see COPYING.GPL)
8 */
9
10 #define _GNU_SOURCE 1 /* for O_NOFOLLOW in Linux */
11
12 #include <sys/types.h>
13
14 #include "darkstat.h"
15 #include "err.h"
16 #include "hosts_db.h"
17 #include "graph_db.h"
18 #include "db.h"
19
20 #include <netinet/in.h> /* for ntohs() and friends */
21 #include <assert.h>
22 #include <fcntl.h>
23 #include <string.h>
24 #include <unistd.h>
25
26 static const unsigned char export_file_header[] = {0xDA, 0x31, 0x41, 0x59};
27 static const unsigned char export_tag_hosts_ver1[] = {0xDA, 'H', 'S', 0x01};
28 static const unsigned char export_tag_graph_ver1[] = {0xDA, 'G', 'R', 0x01};
29
30 #ifndef swap64
31 static inline uint64_t
32 swap64(uint64_t _x)
33 {
34 /* this is __bswap64 from:
35 * $FreeBSD: src/sys/i386/include/endian.h,v 1.41$
36 */
37 return ((_x >> 56) | ((_x >> 40) & 0xff00) | ((_x >> 24) & 0xff0000) |
38 ((_x >> 8) & 0xff000000) | ((_x << 8) & ((uint64_t)0xff << 32)) |
39 ((_x << 24) & ((uint64_t)0xff << 40)) |
40 ((_x << 40) & ((uint64_t)0xff << 48)) | ((_x << 56)));
41 }
42 #endif
43
44 uint64_t
45 hton64(const uint64_t ho)
46 {
47 if (ntohs(0x1234) == 0x1234) return ho;
48 else return swap64(ho);
49 }
50
51 uint64_t
52 ntoh64(const uint64_t no)
53 {
54 return hton64(no);
55 }
56
57 void
58 test_64order(void)
59 {
60 static const char str[] = { 0x79,0x74,0x69,0x63,0x6b,0x72,0x65,0x6a };
61 uint64_t no, ho;
62
63 assert(sizeof(no) == 8);
64 memcpy(&no, str, 8);
65 ho = ntoh64(no);
66 assert(ho == 8751735851613054314ULL);
67 assert(hton64(ntoh64(no)) == no);
68 }
69
70 /* ---------------------------------------------------------------------------
71 * Read-from-file helpers. They all return 0 on failure, and 1 on success.
72 */
73
74 unsigned int
75 xtell(const int fd)
76 {
77 off_t ofs = lseek(fd, 0, SEEK_CUR);
78 if (ofs == -1)
79 err(1, "lseek(0, SEEK_CUR) failed");
80 return (unsigned int)ofs;
81 }
82
83 /* Read <len> bytes from <fd>, warn() and return 0 on failure,
84 * or return 1 for success.
85 */
86 int
87 readn(const int fd, void *dest, const size_t len)
88 {
89 ssize_t numread;
90
91 numread = read(fd, dest, len);
92 if (numread == (ssize_t)len) return 1;
93
94 if (numread == -1)
95 warn("at pos %u: couldn't read %d bytes", xtell(fd), (int)len);
96 else
97 warnx("at pos %u: tried to read %d bytes, got %d",
98 xtell(fd), (int)len, (int)numread);
99 return 0;
100 }
101
102 /* Read a byte. */
103 int
104 read8(const int fd, uint8_t *dest)
105 {
106 assert(sizeof(*dest) == 1);
107 return readn(fd, dest, sizeof(*dest));
108 }
109
110 /* Read a byte and compare it to the expected data.
111 * Returns 0 on failure or mismatch, 1 on success.
112 */
113 int
114 expect8(const int fd, uint8_t expecting)
115 {
116 uint8_t tmp;
117
118 assert(sizeof(tmp) == 1);
119 if (!readn(fd, &tmp, sizeof(tmp))) return 0;
120 if (tmp == expecting) return 1;
121
122 warnx("at pos %u: expecting 0x%02x, got 0x%02x",
123 xtell(fd)-1, expecting, tmp);
124 return 0;
125 }
126
127 /* Read a network order uint16_t from a file
128 * and store it in host order in memory.
129 */
130 int
131 read16(const int fd, uint16_t *dest)
132 {
133 uint16_t tmp;
134
135 assert(sizeof(tmp) == 2);
136 if (!read(fd, &tmp, sizeof(tmp))) return 0;
137 *dest = ntohs(tmp);
138 return 1;
139 }
140
141 /* Read a network order uint32_t from a file
142 * and store it in host order in memory.
143 */
144 int
145 read32(const int fd, uint32_t *dest)
146 {
147 uint32_t tmp;
148
149 assert(sizeof(tmp) == 4);
150 if (!read(fd, &tmp, sizeof(tmp))) return 0;
151 *dest = ntohl(tmp);
152 return 1;
153 }
154
155 /* Read a struct addr from a file. Addresses are always stored in network
156 * order, both in the file and in the host's memory (FIXME: is that right?)
157 */
158 int
159 readaddr(const int fd, struct addr *dest)
160 {
161 assert(dest->family == IPv4 || dest->family == AF_INET6);
162
163 if (dest->family == IPv4)
164 return readn(fd, &(dest->ip.v4), sizeof(dest->ip.v4));
165 else
166 return readn(fd, dest->ip.v6.s6_addr, sizeof(dest->ip.v6.s6_addr));
167 }
168
169 /* Read a network order uint64_t from a file
170 * and store it in host order in memory.
171 */
172 int
173 read64(const int fd, uint64_t *dest)
174 {
175 uint64_t tmp;
176
177 assert(sizeof(tmp) == 8);
178 if (!read(fd, &tmp, sizeof(tmp))) return 0;
179 *dest = ntoh64(tmp);
180 return 1;
181 }
182
183 /* ---------------------------------------------------------------------------
184 * Write-to-file helpers. They all return 0 on failure, and 1 on success.
185 */
186
187 /* Write <len> bytes to <fd>, warn() and return 0 on failure,
188 * or return 1 for success.
189 */
190 int
191 writen(const int fd, const void *dest, const size_t len)
192 {
193 ssize_t numwr;
194
195 numwr = write(fd, dest, len);
196 if (numwr == (ssize_t)len) return 1;
197
198 if (numwr == -1)
199 warn("couldn't write %d bytes", (int)len);
200 else
201 warnx("tried to write %d bytes but wrote %d",
202 (int)len, (int)numwr);
203 return 0;
204 }
205
206 int
207 write8(const int fd, const uint8_t i)
208 {
209 assert(sizeof(i) == 1);
210 return writen(fd, &i, sizeof(i));
211 }
212
213 /* Given a uint16_t in host order, write it to a file in network order.
214 */
215 int
216 write16(const int fd, const uint16_t i)
217 {
218 uint16_t tmp = htons(i);
219 assert(sizeof(tmp) == 2);
220 return writen(fd, &tmp, sizeof(tmp));
221 }
222
223 /* Given a uint32_t in host order, write it to a file in network order.
224 */
225 int
226 write32(const int fd, const uint32_t i)
227 {
228 uint32_t tmp = htonl(i);
229 assert(sizeof(tmp) == 4);
230 return writen(fd, &tmp, sizeof(tmp));
231 }
232
233 /* Given a uint64_t in host order, write it to a file in network order.
234 */
235 int
236 write64(const int fd, const uint64_t i)
237 {
238 uint64_t tmp = hton64(i);
239 assert(sizeof(tmp) == 8);
240 return writen(fd, &tmp, sizeof(tmp));
241 }
242
243
244 /* Write the active address part in a struct addr to a file.
245 * Addresses are always stored in network order, both in the file and
246 * in the host's memory (FIXME: is that right?)
247 */
248 int
249 writeaddr(const int fd, const struct addr *const a)
250 {
251 if (a->family == IPv4)
252 return writen(fd, &(a->ip.v4), sizeof(a->ip.v4));
253 else {
254 assert(a->family == IPv6);
255 return writen(fd, a->ip.v6.s6_addr, sizeof(a->ip.v6.s6_addr));
256 }
257 }
258
259 /* ---------------------------------------------------------------------------
260 * db import/export code follows.
261 */
262
263 /* Check that the global file header is correct / supported. */
264 int
265 read_file_header(const int fd, const uint8_t expected[4])
266 {
267 uint8_t got[4];
268
269 if (!readn(fd, got, sizeof(got))) return 0;
270
271 /* Check the header data */
272 if (memcmp(got, expected, sizeof(got)) != 0) {
273 warnx("bad header: "
274 "expecting %02x%02x%02x%02x, got %02x%02x%02x%02x",
275 expected[0], expected[1], expected[2], expected[3],
276 got[0], got[1], got[2], got[3]);
277 return 0;
278 }
279 return 1;
280 }
281
282 /* Returns 0 on failure, 1 on success. */
283 static int
284 db_import_from_fd(const int fd)
285 {
286 if (!read_file_header(fd, export_file_header)) return 0;
287 if (!read_file_header(fd, export_tag_hosts_ver1)) return 0;
288 if (!hosts_db_import(fd)) return 0;
289 if (!read_file_header(fd, export_tag_graph_ver1)) return 0;
290 if (!graph_import(fd)) return 0;
291 return 1;
292 }
293
294 void
295 db_import(const char *filename)
296 {
297 int fd = open(filename, O_RDONLY | O_NOFOLLOW);
298 if (fd == -1) {
299 warn("can't import from \"%s\"", filename);
300 return;
301 }
302 if (!db_import_from_fd(fd)) {
303 warnx("import failed");
304 /* don't stay in an inconsistent state: */
305 hosts_db_reset();
306 graph_reset();
307 }
308 close(fd);
309 }
310
311 /* Returns 0 on failure, 1 on success. */
312 static int
313 db_export_to_fd(const int fd)
314 {
315 if (!writen(fd, export_file_header, sizeof(export_file_header)))
316 return 0;
317 if (!writen(fd, export_tag_hosts_ver1, sizeof(export_tag_hosts_ver1)))
318 return 0;
319 if (!hosts_db_export(fd))
320 return 0;
321 if (!writen(fd, export_tag_graph_ver1, sizeof(export_tag_graph_ver1)))
322 return 0;
323 if (!graph_export(fd))
324 return 0;
325 return 1;
326 }
327
328 void
329 db_export(const char *filename)
330 {
331 int fd = open(filename, O_WRONLY | O_CREAT | O_NOFOLLOW | O_TRUNC, 0600);
332 if (fd == -1) {
333 warn("can't export to \"%s\"", filename);
334 return;
335 }
336 verbosef("exporting db to file \"%s\"", filename);
337 if (!db_export_to_fd(fd))
338 warnx("export failed");
339 else
340 verbosef("export successful");
341
342 /* FIXME: should write to another filename and use the rename() syscall to
343 * atomically update the output file on success
344 */
345 close(fd);
346 }
347
348 /* vim:set ts=3 sw=3 tw=78 et: */