1 /* Copyright (c) 2009, 2010 Nicira Networks
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
30 #include "ovsdb-error.h"
32 #include "transaction.h"
35 #define THIS_MODULE VLM_ovsdb_log
46 struct lockfile *lockfile;
48 struct ovsdb_error *read_error;
49 struct ovsdb_error *write_error;
50 enum ovsdb_log_mode mode;
53 /* Attempts to open 'name' with the specified 'open_mode'. On success, stores
54 * the new log into '*filep' and returns NULL; otherwise returns NULL and
55 * stores NULL into '*filep'.
57 * Whether the file will be locked using lockfile_lock() depends on 'locking':
58 * use true to lock it, false not to lock it, or -1 to lock it only if
59 * 'open_mode' is a mode that allows writing.
62 ovsdb_log_open(const char *name, enum ovsdb_log_open_mode open_mode,
63 int locking, struct ovsdb_log **filep)
65 struct lockfile *lockfile;
66 struct ovsdb_error *error;
67 struct ovsdb_log *file;
75 assert(locking == -1 || locking == false || locking == true);
77 locking = open_mode != OVSDB_LOG_READ_ONLY;
80 int retval = lockfile_lock(name, 0, &lockfile);
82 error = ovsdb_io_error(retval, "%s: failed to lock lockfile",
90 if (open_mode == OVSDB_LOG_READ_ONLY) {
92 } else if (open_mode == OVSDB_LOG_READ_WRITE) {
94 } else if (open_mode == OVSDB_LOG_CREATE) {
95 flags = O_RDWR | O_CREAT | O_EXCL;
99 fd = open(name, flags, 0666);
101 const char *op = open_mode == OVSDB_LOG_CREATE ? "create" : "open";
102 error = ovsdb_io_error(errno, "%s: %s failed", op, name);
106 if (!fstat(fd, &s) && s.st_size == 0) {
107 /* It's (probably) a new file so fsync() its parent directory to ensure
108 * that its directory entry is committed to disk. */
109 char *dir = dir_name(name);
110 int dirfd = open(dir, O_RDONLY);
112 if (fsync(dirfd) && errno != EINVAL) {
113 VLOG_ERR("%s: fsync failed (%s)", dir, strerror(errno));
117 VLOG_ERR("%s: open failed (%s)", dir, strerror(errno));
122 stream = fdopen(fd, open_mode == OVSDB_LOG_READ_ONLY ? "rb" : "w+b");
124 error = ovsdb_io_error(errno, "%s: fdopen failed", name);
128 file = xmalloc(sizeof *file);
129 file->name = xstrdup(name);
130 file->lockfile = lockfile;
131 file->stream = stream;
133 file->read_error = NULL;
134 file->write_error = NULL;
135 file->mode = OVSDB_LOG_READ;
142 lockfile_unlock(lockfile);
148 ovsdb_log_close(struct ovsdb_log *file)
152 fclose(file->stream);
153 lockfile_unlock(file->lockfile);
154 ovsdb_error_destroy(file->read_error);
155 ovsdb_error_destroy(file->write_error);
160 static const char magic[] = "OVSDB JSON ";
163 parse_header(char *header, unsigned long int *length,
164 uint8_t sha1[SHA1_DIGEST_SIZE])
168 /* 'header' must consist of a magic string... */
169 if (strncmp(header, magic, strlen(magic))) {
173 /* ...followed by a length in bytes... */
174 *length = strtoul(header + strlen(magic), &p, 10);
175 if (!*length || *length == ULONG_MAX || *p != ' ') {
180 /* ...followed by a SHA-1 hash... */
181 if (!sha1_from_hex(sha1, p)) {
184 p += SHA1_HEX_DIGEST_LEN;
186 /* ...and ended by a new-line. */
194 struct ovsdb_log_read_cbdata {
196 struct ovsdb_log *file;
198 unsigned long length;
201 static struct ovsdb_error *
202 parse_body(struct ovsdb_log *file, off_t offset, unsigned long int length,
203 uint8_t sha1[SHA1_DIGEST_SIZE], struct json **jsonp)
205 struct json_parser *parser;
209 parser = json_parser_create(JSPF_TRAILER);
215 chunk = MIN(length, sizeof input);
216 if (fread(input, 1, chunk, file->stream) != chunk) {
217 json_parser_abort(parser);
218 return ovsdb_io_error(ferror(file->stream) ? errno : EOF,
219 "%s: error reading %lu bytes "
220 "starting at offset %lld", file->name,
221 length, (long long int) offset);
223 sha1_update(&ctx, input, chunk);
224 json_parser_feed(parser, input, chunk);
228 sha1_final(&ctx, sha1);
229 *jsonp = json_parser_finish(parser);
234 ovsdb_log_read(struct ovsdb_log *file, struct json **jsonp)
236 uint8_t expected_sha1[SHA1_DIGEST_SIZE];
237 uint8_t actual_sha1[SHA1_DIGEST_SIZE];
238 struct ovsdb_error *error;
240 unsigned long data_length;
244 *jsonp = json = NULL;
246 if (file->read_error) {
247 return ovsdb_error_clone(file->read_error);
248 } else if (file->mode == OVSDB_LOG_WRITE) {
249 return OVSDB_BUG("reading file in write mode");
252 if (!fgets(header, sizeof header, file->stream)) {
253 if (feof(file->stream)) {
256 error = ovsdb_io_error(errno, "%s: read failed", file->name);
261 if (!parse_header(header, &data_length, expected_sha1)) {
262 error = ovsdb_syntax_error(NULL, NULL, "%s: parse error at offset "
263 "%lld in header line \"%.*s\"",
264 file->name, (long long int) file->offset,
265 (int) strcspn(header, "\n"), header);
269 data_offset = file->offset + strlen(header);
270 error = parse_body(file, data_offset, data_length, actual_sha1, &json);
275 if (memcmp(expected_sha1, actual_sha1, SHA1_DIGEST_SIZE)) {
276 error = ovsdb_syntax_error(NULL, NULL, "%s: %lu bytes starting at "
277 "offset %lld have SHA-1 hash "SHA1_FMT" "
278 "but should have hash "SHA1_FMT,
279 file->name, data_length,
280 (long long int) data_offset,
281 SHA1_ARGS(actual_sha1),
282 SHA1_ARGS(expected_sha1));
286 if (json->type == JSON_STRING) {
287 error = ovsdb_syntax_error(NULL, NULL, "%s: %lu bytes starting at "
288 "offset %lld are not valid JSON (%s)",
289 file->name, data_length,
290 (long long int) data_offset,
295 file->offset = data_offset + data_length;
300 file->read_error = ovsdb_error_clone(error);
306 ovsdb_log_write(struct ovsdb_log *file, struct json *json)
308 uint8_t sha1[SHA1_DIGEST_SIZE];
309 struct ovsdb_error *error;
316 if (file->write_error) {
317 return ovsdb_error_clone(file->write_error);
318 } else if (file->mode == OVSDB_LOG_READ) {
319 file->mode = OVSDB_LOG_WRITE;
320 if (fseeko(file->stream, file->offset, SEEK_SET)) {
321 error = ovsdb_io_error(errno, "%s: cannot seek to offset %lld",
322 file->name, (long long int) file->offset);
325 if (ftruncate(fileno(file->stream), file->offset)) {
326 error = ovsdb_io_error(errno, "%s: cannot truncate to length %lld",
327 file->name, (long long int) file->offset);
332 if (json->type != JSON_OBJECT && json->type != JSON_ARRAY) {
333 error = OVSDB_BUG("bad JSON type");
337 /* Compose content. Add a new-line (replacing the null terminator) to make
338 * the file easier to read, even though it has no semantic value. */
339 json_string = json_to_string(json, 0);
340 length = strlen(json_string) + 1;
341 json_string[length - 1] = '\n';
343 /* Compose header. */
344 sha1_bytes(json_string, length, sha1);
345 snprintf(header, sizeof header, "%s%zu "SHA1_FMT"\n",
346 magic, length, SHA1_ARGS(sha1));
349 if (fwrite(header, strlen(header), 1, file->stream) != 1
350 || fwrite(json_string, length, 1, file->stream) != 1
351 || fflush(file->stream))
353 error = ovsdb_io_error(errno, "%s: write failed", file->name);
355 /* Remove any partially written data, ignoring errors since there is
356 * nothing further we can do. */
357 ignore(ftruncate(fileno(file->stream), file->offset));
362 file->offset += strlen(header) + length;
367 file->write_error = ovsdb_error_clone(error);
373 ovsdb_log_commit(struct ovsdb_log *file)
375 if (fsync(fileno(file->stream))) {
376 return ovsdb_io_error(errno, "%s: fsync failed", file->name);