fifolog_write_poll.c revision 188007 
1/*-
2 * Copyright (c) 2005-2008 Poul-Henning Kamp
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/usr.sbin/fifolog/lib/fifolog_write_poll.c 188007 2009-02-02 14:29:15Z phk $
27 */
28
29#include <assert.h>
30#include <stdio.h>
31#include <string.h>
32#include <stdlib.h>
33#include <unistd.h>
34#include <time.h>
35#include <sys/endian.h>
36
37#include <zlib.h>
38
39#include "fifolog.h"
40#include "libfifolog.h"
41#include "libfifolog_int.h"
42#include "fifolog_write.h"
43#include "miniobj.h"
44
45#define ALLOC(ptr, size) do {                   \
46	(*(ptr)) = calloc(size, 1);             \
47	assert(*(ptr) != NULL);                 \
48} while (0)
49
50
51const char *fifolog_write_statnames[] = {
52[FIFOLOG_PT_BYTES_PRE] =	"Bytes before compression",
53[FIFOLOG_PT_BYTES_POST] =	"Bytes after compression",
54[FIFOLOG_PT_WRITES] =		"Writes",
55[FIFOLOG_PT_FLUSH] =		"Flushes",
56[FIFOLOG_PT_SYNC] =		"Syncs",
57[FIFOLOG_PT_RUNTIME] =		"Runtime"
58};
59
60/*
61 * Check that everything is all right
62 */
63static void
64fifolog_write_assert(const struct fifolog_writer *f)
65{
66
67	CHECK_OBJ_NOTNULL(f, FIFOLOG_WRITER_MAGIC);
68	assert(f->iptr == f->ff->zs->next_in + f->ff->zs->avail_in);
69	assert(f->ff->zs->next_out + f->ff->zs->avail_out == \
70	    f->ff->recbuf + f->ff->recsize);
71}
72
73struct fifolog_writer *
74fifolog_write_new(void)
75{
76	struct fifolog_writer *f;
77
78	ALLOC(&f, sizeof *f);
79	f->magic = FIFOLOG_WRITER_MAGIC;
80	return (f);
81}
82
83void
84fifolog_write_destroy(struct fifolog_writer *f)
85{
86	CHECK_OBJ_NOTNULL(f, FIFOLOG_WRITER_MAGIC);
87	free(f);
88}
89
90void
91fifolog_write_close(struct fifolog_writer *f)
92{
93
94	CHECK_OBJ_NOTNULL(f, FIFOLOG_WRITER_MAGIC);
95	fifolog_int_close(&f->ff);
96	free(f->ff);
97	if (f->ibuf != NULL)
98		free(f->ibuf);
99	free(f);
100}
101
102static void
103fifo_prepobuf(struct fifolog_writer *f, time_t now, int flag)
104{
105
106	memset(f->ff->recbuf, 0, f->ff->recsize);
107	f->ff->zs->next_out = f->ff->recbuf + 5;
108	f->ff->zs->avail_out = f->ff->recsize - 5;
109	if (f->recno == 0 && f->seq == 0) {
110		srandomdev();
111		do {
112			f->seq = random();
113		} while (f->seq == 0);
114	}
115	be32enc(f->ff->recbuf, f->seq++);
116	f->ff->recbuf[4] = f->flag;
117	f->flag = 0;
118	if (flag) {
119		f->ff->recbuf[4] |= FIFOLOG_FLG_SYNC;
120		be32enc(f->ff->recbuf + 5, (u_int)now);
121		f->ff->zs->next_out += 4;
122		f->ff->zs->avail_out -= 4;
123	}
124	fifolog_write_assert(f);
125}
126
127const char *
128fifolog_write_open(struct fifolog_writer *f, const char *fn, unsigned writerate, unsigned syncrate, int compression)
129{
130	const char *es;
131	int i;
132	time_t now;
133	off_t o;
134
135	CHECK_OBJ_NOTNULL(f, FIFOLOG_WRITER_MAGIC);
136
137	/* Check for legal compression value */
138	if (compression < Z_DEFAULT_COMPRESSION ||
139	    compression > Z_BEST_COMPRESSION)
140		return ("Illegal compression value");
141
142	f->writerate = writerate;
143	f->syncrate = syncrate;
144	f->compression = compression;
145
146	/* Reset statistics */
147	memset(f->cnt, 0, sizeof f->cnt);
148
149	es = fifolog_int_open(&f->ff, fn, 1);
150	if (es != NULL)
151		return (es);
152	es = fifolog_int_findend(f->ff, &o);
153	if (es != NULL)
154		return (es);
155	i = fifolog_int_read(f->ff, o);
156	if (i)
157		return ("Read error, looking for seq");
158	f->seq = be32dec(f->ff->recbuf);
159	if (f->seq == 0) {
160		/* Empty fifolog */
161		f->seq = random();
162	} else {
163		f->recno = o + 1;
164		f->seq++;
165	}
166
167	f->ibufsize = 32768;
168	ALLOC(&f->ibuf, f->ibufsize);
169	f->iptr = f->ibuf;
170	f->ff->zs->next_in = f->iptr;
171	i = deflateInit(f->ff->zs, (int)f->compression);
172	assert(i == Z_OK);
173
174	f->flag |= FIFOLOG_FLG_RESTART;
175
176	time(&now);
177	fifo_prepobuf(f, now, 1);
178	f->starttime = now;
179
180	fifolog_write_assert(f);
181	return (NULL);
182}
183
184static void
185fifo_writerec(struct fifolog_writer *f)
186{
187	int i;
188	time_t t;
189
190	fifolog_write_assert(f);
191	f->writes_since_sync++;
192
193	assert(f->recno < f->ff->logsize);
194	f->cnt[FIFOLOG_PT_BYTES_POST] += f->ff->recsize - f->ff->zs->avail_out;
195	if (f->ff->zs->avail_out == 0) {
196		/* nothing */
197	} else if (f->ff->zs->avail_out <= 255) {
198		f->ff->recbuf[f->ff->recsize - 1] =
199		    (u_char)f->ff->zs->avail_out;
200		f->ff->recbuf[4] |= FIFOLOG_FLG_1BYTE;
201	} else {
202		be32enc(f->ff->recbuf + f->ff->recsize - 4,
203		    f->ff->zs->avail_out);
204		f->ff->recbuf[4] |= FIFOLOG_FLG_4BYTE;
205	}
206	i = pwrite(f->ff->fd, f->ff->recbuf, f->ff->recsize,
207		(f->recno + 1) * f->ff->recsize);
208	assert (i == (int)f->ff->recsize);
209	if (++f->recno == f->ff->logsize)
210		f->recno = 0;
211	f->cnt[FIFOLOG_PT_WRITES]++;
212	time(&t);
213	f->cnt[FIFOLOG_PT_RUNTIME] = t - f->starttime; /*lint !e776 */
214	fifolog_write_assert(f);
215}
216
217int
218fifolog_write_poll(struct fifolog_writer *f, time_t now)
219{
220	int i, fl, bo, bf;
221
222	if (now == 0)
223		time(&now);
224
225	fifolog_write_assert(f);
226	if (f->cleanup || now >= (int)(f->lastsync + f->syncrate)) {
227		/*
228		 * We always check the sync timer, otherwise a flood of data
229		 * would not get any sync records at all
230		 */
231		f->cleanup = 0;
232		fl = Z_FINISH;
233		f->lastsync = now;
234		f->lastwrite = now;
235		f->cnt[FIFOLOG_PT_SYNC]++;
236	} else if (f->ff->zs->avail_in == 0 &&
237	    now >= (int)(f->lastwrite + f->writerate)) {
238		/*
239		 * We only check for writerate timeouts when the input
240		 * buffer is empty.  It would be silly to force a write if
241		 * pending input could cause it to happen on its own.
242		 */
243		fl = Z_SYNC_FLUSH;
244		f->lastwrite = now;
245		f->cnt[FIFOLOG_PT_FLUSH]++;
246	} else if (f->ff->zs->avail_in == 0)
247		return (0);			/* nothing to do */
248	else
249		fl = Z_NO_FLUSH;
250
251	for (;;) {
252		assert(f->ff->zs->avail_out > 0);
253
254		bf = f->ff->zs->avail_out;
255
256		i = deflate(f->ff->zs, fl);
257		assert (i == Z_OK || i == Z_BUF_ERROR || i == Z_STREAM_END);
258
259		bo = f->ff->zs->avail_out;
260
261		/* If we have output space and not in a hurry.. */
262		if (bo > 0 && fl == Z_NO_FLUSH)
263			break;
264
265		/* Write output buffer, if anything in it */
266		if (bo != bf)
267			fifo_writerec(f);
268
269		/* If the buffer were full, we need to check again */
270		if (bo == 0) {
271			fifo_prepobuf(f, now, 0);
272			continue;
273		}
274
275		if (fl == Z_FINISH) {
276			/* Make next record a SYNC record */
277			fifo_prepobuf(f, now, 1);
278			/* And reset the zlib engine */
279			i = deflateReset(f->ff->zs);
280			assert(i == Z_OK);
281			f->writes_since_sync = 0;
282		} else {
283			fifo_prepobuf(f, now, 0);
284		}
285		break;
286	}
287
288	if (f->ff->zs->avail_in == 0) {
289		/* Reset input buffer when empty */
290		f->iptr = f->ibuf;
291		f->ff->zs->next_in = f->iptr;
292	}
293
294	fifolog_write_assert(f);
295	return (1);
296}
297
298static void
299fifolog_acct(struct fifolog_writer *f, unsigned bytes)
300{
301
302	f->ff->zs->avail_in += bytes;
303	f->iptr += bytes;
304	f->cnt[FIFOLOG_PT_BYTES_PRE] += bytes;
305}
306
307/*
308 * Attempt to write an entry.
309 * Return zero if there is no space, one otherwise
310 */
311
312int
313fifolog_write_bytes(struct fifolog_writer *f, uint32_t id, time_t now, const void *ptr, unsigned len)
314{
315	u_int l;
316	const unsigned char *p;
317
318	fifolog_write_assert(f);
319	assert(!(id & (FIFOLOG_TIMESTAMP|FIFOLOG_LENGTH)));
320	assert(ptr != NULL);
321
322	p = ptr;
323	if (len == 0) {
324		len = strlen(ptr) + 1;
325		l = 4 + len;		/* id */
326	} else {
327		assert(len <= 255);
328		id |= FIFOLOG_LENGTH;
329		l = 5 + len;		/* id + len */
330	}
331
332	l += 4; 		/* A timestamp may be necessary */
333
334	/* Now do timestamp, if needed */
335	if (now == 0)
336		time(&now);
337
338	assert(l < f->ibufsize);
339
340	/* Return if there is not enough space */
341	if (f->iptr + l > f->ibuf + f->ibufsize)
342		return (0);
343
344	if (now != f->last) {
345		id |= FIFOLOG_TIMESTAMP;
346		f->last = now;
347	}
348
349	/* Emit instance+flag and length */
350	be32enc(f->iptr, id);
351	fifolog_acct(f, 4);
352
353	if (id & FIFOLOG_TIMESTAMP) {
354		be32enc(f->iptr, (uint32_t)f->last);
355		fifolog_acct(f, 4);
356	}
357	if (id & FIFOLOG_LENGTH) {
358		f->iptr[0] = (u_char)len;
359		fifolog_acct(f, 1);
360	}
361
362	assert (len > 0);
363	memcpy(f->iptr, p, len);
364	fifolog_acct(f, len);
365	fifolog_write_assert(f);
366	return (1);
367}
368
369/*
370 * Write an entry, polling until success.
371 * Long binary entries are broken into 255 byte chunks.
372 */
373
374void
375fifolog_write_bytes_poll(struct fifolog_writer *f, uint32_t id, time_t now, const void *ptr, unsigned len)
376{
377	u_int l;
378	const unsigned char *p;
379
380	fifolog_write_assert(f);
381
382	assert(!(id & (FIFOLOG_TIMESTAMP|FIFOLOG_LENGTH)));
383	assert(ptr != NULL);
384
385	if (len == 0) {
386		while (!fifolog_write_bytes(f, id, now, ptr, len)) {
387			(void)fifolog_write_poll(f, now);
388			(void)usleep(10000);
389		}
390	} else {
391		p = ptr;
392		for (p = ptr; len > 0; len -= l, p += l) {
393			l = len;
394			if (l > 255)
395				l = 255;
396			while (!fifolog_write_bytes(f, id, now, p, l)) {
397				(void)fifolog_write_poll(f, now);
398				(void)usleep(10000);
399			}
400		}
401	}
402	fifolog_write_assert(f);
403}
404
405int
406fifolog_write_flush(struct fifolog_writer *f)
407{
408	int i;
409
410	fifolog_write_assert(f);
411
412	f->cleanup = 1;
413	for (i = 0; fifolog_write_poll(f, 0); i = 1)
414		continue;
415	fifolog_write_assert(f);
416	return (i);
417}
418