Skip per-host accounting if --hosts-max is zero.
[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 an in_addr_t 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, in_addr_t *dest)
160 {
161 assert(sizeof(*dest) == 4);
162 return readn(fd, dest, sizeof(*dest));
163 }
164
165 /* Read a network order uint64_t from a file
166 * and store it in host order in memory.
167 */
168 int
169 read64(const int fd, uint64_t *dest)
170 {
171 uint64_t tmp;
172
173 assert(sizeof(tmp) == 8);
174 if (!read(fd, &tmp, sizeof(tmp))) return 0;
175 *dest = ntoh64(tmp);
176 return 1;
177 }
178
179 /* ---------------------------------------------------------------------------
180 * Write-to-file helpers. They all return 0 on failure, and 1 on success.
181 */
182
183 /* Write <len> bytes to <fd>, warn() and return 0 on failure,
184 * or return 1 for success.
185 */
186 int
187 writen(const int fd, const void *dest, const size_t len)
188 {
189 ssize_t numwr;
190
191 numwr = write(fd, dest, len);
192 if (numwr == (ssize_t)len) return 1;
193
194 if (numwr == -1)
195 warn("couldn't write %d bytes", (int)len);
196 else
197 warnx("tried to write %d bytes but wrote %d",
198 (int)len, (int)numwr);
199 return 0;
200 }
201
202 int
203 write8(const int fd, const uint8_t i)
204 {
205 assert(sizeof(i) == 1);
206 return writen(fd, &i, sizeof(i));
207 }
208
209 /* Given a uint16_t in host order, write it to a file in network order.
210 */
211 int
212 write16(const int fd, const uint16_t i)
213 {
214 uint16_t tmp = htons(i);
215 assert(sizeof(tmp) == 2);
216 return writen(fd, &tmp, sizeof(tmp));
217 }
218
219 /* Given a uint32_t in host order, write it to a file in network order.
220 */
221 int
222 write32(const int fd, const uint32_t i)
223 {
224 uint32_t tmp = htonl(i);
225 assert(sizeof(tmp) == 4);
226 return writen(fd, &tmp, sizeof(tmp));
227 }
228
229 /* Given a uint64_t in host order, write it to a file in network order.
230 */
231 int
232 write64(const int fd, const uint64_t i)
233 {
234 uint64_t tmp = hton64(i);
235 assert(sizeof(tmp) == 8);
236 return writen(fd, &tmp, sizeof(tmp));
237 }
238
239
240 /* Write an in_addr_t to a file. Addresses are always stored in network
241 * order, both in the file and in the host's memory (FIXME: is that right?)
242 */
243 int
244 writeaddr(const int fd, const in_addr_t addr)
245 {
246 assert(sizeof(addr) == 4);
247 return writen(fd, &addr, sizeof(addr));
248 }
249
250 /* ---------------------------------------------------------------------------
251 * db import/export code follows.
252 */
253
254 /* Check that the global file header is correct / supported. */
255 int
256 read_file_header(const int fd, const uint8_t expected[4])
257 {
258 uint8_t got[4];
259
260 if (!readn(fd, got, sizeof(got))) return 0;
261
262 /* Check the header data */
263 if (memcmp(got, expected, sizeof(got)) != 0) {
264 warnx("bad header: "
265 "expecting %02x%02x%02x%02x, got %02x%02x%02x%02x",
266 expected[0], expected[1], expected[2], expected[3],
267 got[0], got[1], got[2], got[3]);
268 return 0;
269 }
270 return 1;
271 }
272
273 /* Returns 0 on failure, 1 on success. */
274 static int
275 db_import_from_fd(const int fd)
276 {
277 if (!read_file_header(fd, export_file_header)) return 0;
278 if (!read_file_header(fd, export_tag_hosts_ver1)) return 0;
279 if (!hosts_db_import(fd)) return 0;
280 if (!read_file_header(fd, export_tag_graph_ver1)) return 0;
281 if (!graph_import(fd)) return 0;
282 return 1;
283 }
284
285 void
286 db_import(const char *filename)
287 {
288 int fd = open(filename, O_RDONLY | O_NOFOLLOW);
289 if (fd == -1) {
290 warn("can't import from \"%s\"", filename);
291 return;
292 }
293 if (!db_import_from_fd(fd)) {
294 warnx("import failed");
295 /* don't stay in an inconsistent state: */
296 hosts_db_reset();
297 graph_reset();
298 }
299 close(fd);
300 }
301
302 /* Returns 0 on failure, 1 on success. */
303 static int
304 db_export_to_fd(const int fd)
305 {
306 if (!writen(fd, export_file_header, sizeof(export_file_header)))
307 return 0;
308 if (!writen(fd, export_tag_hosts_ver1, sizeof(export_tag_hosts_ver1)))
309 return 0;
310 if (!hosts_db_export(fd))
311 return 0;
312 if (!writen(fd, export_tag_graph_ver1, sizeof(export_tag_graph_ver1)))
313 return 0;
314 if (!graph_export(fd))
315 return 0;
316 return 1;
317 }
318
319 void
320 db_export(const char *filename)
321 {
322 int fd = open(filename, O_WRONLY | O_CREAT | O_NOFOLLOW | O_TRUNC, 0600);
323 if (fd == -1) {
324 warn("can't export to \"%s\"", filename);
325 return;
326 }
327 verbosef("exporting db to file \"%s\"", filename);
328 if (!db_export_to_fd(fd))
329 warnx("export failed");
330 else
331 verbosef("export successful");
332
333 /* FIXME: should write to another filename and use the rename() syscall to
334 * atomically update the output file on success
335 */
336 close(fd);
337 }
338
339 /* vim:set ts=3 sw=3 tw=78 et: */