1 /*****************************************************************************
2 * RRDtool 1.2.23 Copyright by Tobi Oetiker, 1997-2007
3 *****************************************************************************
4 * rrd_open.c Open an RRD File
5 *****************************************************************************
8 * Revision 1.10 2004/05/26 22:11:12 oetiker
9 * reduce compiler warnings. Many small fixes. -- Mike Slifcak <slif@bellsouth.net>
11 * Revision 1.9 2003/04/29 21:56:49 oetiker
12 * readline in rrd_open.c reads the file in 8 KB blocks, and calls realloc for
13 * each block. realloc is very slow in Mac OS X for huge blocks, e.g. when
14 * restoring databases from huge xml files. This patch finds the size of the
15 * file, and starts out with malloc'ing the full size.
16 * -- Peter Speck <speck@ruc.dk>
18 * Revision 1.8 2003/04/11 19:43:44 oetiker
19 * New special value COUNT which allows calculations based on the position of a
20 * value within a data set. Bug fix in rrd_rpncalc.c. PREV returned erroneus
21 * value for the second value. Bug fix in rrd_restore.c. Bug causing seek error
22 * when accesing an RRD restored from an xml that holds an RRD version <3.
23 * -- Ruben Justo <ruben@ainek.com>
25 * Revision 1.7 2003/03/31 21:22:12 oetiker
26 * enables RRDtool updates with microsecond or in case of windows millisecond
27 * precision. This is needed to reduce time measurement error when archive step
28 * is small. (<30s) -- Sasha Mikheev <sasha@avalon-net.co.il>
30 * Revision 1.6 2003/02/13 07:05:27 oetiker
31 * Find attached the patch I promised to send to you. Please note that there
32 * are three new source files (src/rrd_is_thread_safe.h, src/rrd_thread_safe.c
33 * and src/rrd_not_thread_safe.c) and the introduction of librrd_th. This
34 * library is identical to librrd, but it contains support code for per-thread
35 * global variables currently used for error information only. This is similar
36 * to how errno per-thread variables are implemented. librrd_th must be linked
37 * alongside of libpthred
39 * There is also a new file "THREADS", holding some documentation.
41 * -- Peter Stamfest <peter@stamfest.at>
43 * Revision 1.5 2002/06/20 00:21:03 jake
44 * More Win32 build changes; thanks to Kerry Calvert.
46 * Revision 1.4 2002/02/01 20:34:49 oetiker
47 * fixed version number and date/time
49 * Revision 1.3 2001/03/04 13:01:55 oetiker
50 * Aberrant Behavior Detection support. A brief overview added to rrdtool.pod.
51 * Major updates to rrd_update.c, rrd_create.c. Minor update to other core files.
52 * This is backwards compatible! But new files using the Aberrant stuff are not readable
53 * by old rrdtool versions. See http://cricket.sourceforge.net/aberrant/rrd_hw.htm
54 * -- Jake Brutlag <jakeb@corp.webtv.net>
56 * Revision 1.2 2001/03/04 10:29:20 oetiker
57 * fixed filedescriptor leak
58 * -- Mike Franusich <mike@franusich.com>
60 * Revision 1.1.1.1 2001/02/25 22:25:05 oetiker
63 *****************************************************************************/
69 /* open a database file, return its header and a open filehandle */
70 /* positioned to the first cdp in the first rra */
73 const char *const file_name,
78 mode_t mode = S_IRUSR;
79 int version, prot = PROT_READ;
83 rrd_file_t *rrd_file = malloc(sizeof(rrd_file_t));
85 if (rrd_file == NULL) {
86 rrd_set_error("allocating rrd_file descriptor for '%s'", file_name);
89 memset(rrd_file, 0, sizeof(rrd_file_t));
91 if (rdwr == RRD_READWRITE) {
94 } else if (rdwr == RRD_CREAT) {
97 flags |= (O_CREAT | O_TRUNC);
103 if ((rrd_file->fd = open(file_name, flags, mode)) < 0) {
104 rrd_set_error("opening '%s': %s", file_name, rrd_strerror(errno));
108 /* ???: length = lseek(rrd_file->fd, 0, SEEK_END); */
109 /* ??? locking the whole area of the file may overdo it a bit, does it? */
110 if ((fstat(rrd_file->fd, &statb)) < 0) {
111 rrd_set_error("fstat '%s': %s", file_name, rrd_strerror(errno));
114 rrd_file->file_len = statb.st_size;
116 #ifdef HAVE_POSIX_FADVISE
117 /* In general we need no read-ahead when dealing with rrd_files.
118 When we stop reading, it is highly unlikely that we start up again.
119 In this manner we actually save time and diskaccess (and buffer cache).
120 Thanks to Dave Plonka for the Idea of using POSIX_FADV_RANDOM here. */
121 if (0 != posix_fadvise(rrd_file->fd, 0, 0, POSIX_FADV_RANDOM)) {
122 rrd_set_error("setting POSIX_FADV_RANDOM on '%s': %s", file_name,
123 rrd_strerror(errno));
129 if (rdwr == RRD_READWRITE)
131 if (setvbuf((rrd_file->fd),NULL,_IONBF,2)) {
132 rrd_set_error("failed to disable the stream buffer\n");
137 data = mmap(0, rrd_file->file_len, prot, MAP_SHARED,
138 rrd_file->fd, offset);
140 /* lets see if the first read worked */
141 if (data == MAP_FAILED) {
142 rrd_set_error("error mmaping file '%s'", file_name);
145 rrd_file->file_start = data;
147 if (rrd == NULL) { /*XXX: currently not used! */
148 /* We will read everything in a moment (copying) */
149 madvise(data, rrd_file->file_len, MADV_WILLNEED | MADV_SEQUENTIAL);
152 /* We do not need to read anything in for the moment */
153 madvise(data, rrd_file->file_len, MADV_DONTNEED);
157 /* the stat_head will be needed soonish, so hint accordingly */
158 madvise(data + offset, sizeof(stat_head_t), MADV_WILLNEED);
161 rrd->stat_head = (stat_head_t *) (data + offset);
162 offset += sizeof(stat_head_t);
164 /* lets do some test if we are on track ... */
165 if (memcmp(rrd->stat_head->cookie, RRD_COOKIE, sizeof(RRD_COOKIE)) != 0) {
166 rrd_set_error("'%s' is not an RRD file", file_name);
167 goto out_nullify_head;
170 if (rrd->stat_head->float_cookie != FLOAT_COOKIE) {
171 rrd_set_error("This RRD was created on other architecture");
172 goto out_nullify_head;
175 version = atoi(rrd->stat_head->version);
177 if (version > atoi(RRD_VERSION)) {
178 rrd_set_error("can't handle RRD file version %s",
179 rrd->stat_head->version);
180 goto out_nullify_head;
183 /* the ds_def will be needed soonish, so hint accordingly */
184 madvise(data + offset, sizeof(ds_def_t) * rrd->stat_head->ds_cnt,
187 rrd->ds_def = (ds_def_t *) (data + offset);
188 offset += sizeof(ds_def_t) * rrd->stat_head->ds_cnt;
191 /* the rra_def will be needed soonish, so hint accordingly */
192 madvise(data + offset, sizeof(rra_def_t) * rrd->stat_head->rra_cnt,
195 rrd->rra_def = (rra_def_t *) (data + offset);
196 offset += sizeof(rra_def_t) * rrd->stat_head->rra_cnt;
198 /* handle different format for the live_head */
200 rrd->live_head = (live_head_t *) malloc(sizeof(live_head_t));
201 if (rrd->live_head == NULL) {
202 rrd_set_error("live_head_t malloc");
205 memmove(&rrd->live_head->last_up, data + offset, sizeof(long));
206 rrd->live_head->last_up_usec = 0;
209 /* the live_head will be needed soonish, so hint accordingly */
210 madvise(data + offset, sizeof(live_head_t), MADV_WILLNEED);
212 rrd->live_head = (live_head_t *) (data + offset);
213 offset += sizeof(live_head_t);
215 // This doesn't look like it needs madvise
216 rrd->pdp_prep = (pdp_prep_t *) (data + offset);
217 offset += sizeof(pdp_prep_t) * rrd->stat_head->ds_cnt;
219 // This could benefit from madvise()ing
220 rrd->cdp_prep = (cdp_prep_t *) (data + offset);
221 offset += sizeof(cdp_prep_t) *
222 (rrd->stat_head->rra_cnt * rrd->stat_head->ds_cnt);
224 // This could benefit from madvise()ing
225 rrd->rra_ptr = (rra_ptr_t *) (data + offset);
226 offset += sizeof(rra_ptr_t) * rrd->stat_head->rra_cnt;
230 rrd_file->header_len = offset;
231 rrd_file->pos = offset;
232 /* we could close(rrd_file->fd); here, the mapping is still valid anyway */
235 rrd->stat_head = NULL;
241 /* Close a reference to an rrd_file. */
243 rrd_file_t * rrd_file)
248 ret = munmap(rrd_file->file_start, rrd_file->file_len);
250 // rrd_set_error("munmap rrd_file");
257 /* Set position of rrd_file. */
259 rrd_file_t * rrd_file,
266 if (whence == SEEK_SET)
268 else if (whence == SEEK_CUR)
269 rrd_file->pos += off;
270 else if (whence == SEEK_END)
271 rrd_file->pos = rrd_file->file_len + off;
273 ret = lseek(rrd_file->fd, off, whence);
275 rrd_set_error("lseek: %s", rrd_strerror(errno));
278 //XXX: mimic fseek, which returns 0 upon success
279 return ret == -1; //XXX: or just ret to mimic lseek
282 /* Get current position in rrd_file. */
284 rrd_file_t * rrd_file)
286 return rrd_file->pos;
289 /* read count bytes into buffer buf, starting at rrd_file->pos.
290 * Returns the number of bytes read. */
292 rrd_file_t * rrd_file,
297 char *pos = rrd_file->file_start + rrd_file->pos;
299 buf = memmove(buf, pos, count);
304 ret = read(rrd_file->fd, buf, count);
305 //XXX: eventually add generic rrd_set_error(""); here
310 /* write count bytes from buffer buf to the current position
311 * rrd_file->pos of rrd_file->fd. */
313 rrd_file_t * rrd_file,
322 off = rrd_file->file_start + rrd_file->pos;
323 new_pos = memmove(rrd_file->file_start + rrd_file->pos, buf, count);
326 ret = write(rrd_file->fd, buf, count)
331 /* flush all data pending to be written to FD. */
333 rrd_file_t * rrd_file)
335 if (fdatasync(rrd_file->fd) != 0) {
336 rrd_set_error("flushing fd %d: %s", rrd_file->fd,
337 rrd_strerror(errno));
344 rrd->stat_head = NULL;
347 rrd->live_head = NULL;
349 rrd->pdp_prep = NULL;
350 rrd->cdp_prep = NULL;
351 rrd->rrd_value = NULL;
358 if (atoi(rrd->stat_head->version) < 3)
359 free(rrd->live_head);
360 free(rrd->stat_head);
366 free(rrd->rrd_value);
370 /* routine used by external libraries to free memory allocated by
379 const char *file_name,
383 long writecnt = 0, totalcnt = MEMBLK;
388 if ((strcmp("-", file_name) == 0)) {
391 if ((input = fopen(file_name, "rb")) == NULL) {
392 rrd_set_error("opening '%s': %s", file_name, rrd_strerror(errno));
400 } while (c != '\n' && !feof(input));
402 if (strcmp("-", file_name)) {
403 fseek(input, 0, SEEK_END);
404 /* have extra space for detecting EOF without realloc */
405 totalcnt = (ftell(input) + 1) / sizeof(char) - offset;
406 if (totalcnt < MEMBLK)
407 totalcnt = MEMBLK; /* sanitize */
408 fseek(input, offset * sizeof(char), SEEK_SET);
410 if (((*buffer) = (char *) malloc((totalcnt + 4) * sizeof(char))) == NULL) {
411 perror("Allocate Buffer:");
416 fread((*buffer) + writecnt, 1,
417 (totalcnt - writecnt) * sizeof(char), input);
418 if (writecnt >= totalcnt) {
421 rrd_realloc((*buffer),
422 (totalcnt + 4) * sizeof(char))) == NULL) {
423 perror("Realloc Buffer:");
427 } while (!feof(input));
428 (*buffer)[writecnt] = '\0';
429 if (strcmp("-", file_name) != 0) {