fifolog_write_poll.c revision 176998 
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 176998 2008-03-09 19:14:36Z 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	if (f->ibuf != NULL)
97		free(f->ibuf);
98	free(f);
99}
100
101static void
102fifo_prepobuf(struct fifolog_writer *f, time_t now, int flag)
103{
104
105	memset(f->ff->recbuf, 0, f->ff->recsize);
106	f->ff->zs->next_out = f->ff->recbuf + 5;
107	f->ff->zs->avail_out = f->ff->recsize - 5;
108	if (f->recno == 0 && f->seq == 0) {
109		srandomdev();
110		do {
111			f->seq = random();
112		} while (f->seq == 0);
113	}
114	be32enc(f->ff->recbuf, f->seq++);
115	f->ff->recbuf[4] = f->flag;
116	f->flag = 0;
117	if (flag) {
118		f->ff->recbuf[4] |= FIFOLOG_FLG_SYNC;
119		be32enc(f->ff->recbuf + 5, (u_int)now);
120		f->ff->zs->next_out += 4;
121		f->ff->zs->avail_out -= 4;
122	}
123	fifolog_write_assert(f);
124}
125
126const char *
127fifolog_write_open(struct fifolog_writer *f, const char *fn, unsigned writerate, unsigned syncrate, int compression)
128{
129	const char *es;
130	int i;
131	time_t now;
132	off_t o;
133
134	CHECK_OBJ_NOTNULL(f, FIFOLOG_WRITER_MAGIC);
135
136	/* Check for legal compression value */
137	if (compression < Z_DEFAULT_COMPRESSION ||
138	    compression > Z_BEST_COMPRESSION)
139		return ("Illegal compression value");
140
141	f->writerate = writerate;
142	f->syncrate = syncrate;
143	f->compression = compression;
144
145	/* Reset statistics */
146	memset(f->cnt, 0, sizeof f->cnt);
147
148	es = fifolog_int_open(&f->ff, fn, 1);
149	if (es != NULL)
150		return (es);
151	es = fifolog_int_findend(f->ff, &o);
152	if (es != NULL)
153		return (es);
154	if (o == 0) {
155		f->seq = 0;
156		f->recno = 0;
157	} else {
158		i = fifolog_int_read(f->ff, o);
159		if (i)
160			return ("Read error, looking for seq");
161		f->seq = be32dec(f->ff->recbuf) + 1;
162		f->recno = o + 1;
163	}
164
165	f->ibufsize = 32768;
166	ALLOC(&f->ibuf, f->ibufsize);
167	f->iptr = f->ibuf;
168	f->ff->zs->next_in = f->iptr;
169	i = deflateInit(f->ff->zs, (int)f->compression);
170	assert(i == Z_OK);
171
172	f->flag |= FIFOLOG_FLG_RESTART;
173
174	time(&now);
175	fifo_prepobuf(f, now, 1);
176	f->starttime = now;
177
178	fifolog_write_assert(f);
179	return (NULL);
180}
181
182static void
183fifo_writerec(struct fifolog_writer *f)
184{
185	int i;
186	time_t t;
187
188	fifolog_write_assert(f);
189	f->writes_since_sync++;
190
191	assert(f->recno < f->ff->logsize);
192	f->cnt[FIFOLOG_PT_BYTES_POST] += f->ff->recsize - f->ff->zs->avail_out;
193	if (f->ff->zs->avail_out == 0) {
194		/* nothing */
195	} else if (f->ff->zs->avail_out <= 255) {
196		f->ff->recbuf[f->ff->recsize - 1] =
197		    (u_char)f->ff->zs->avail_out;
198		f->ff->recbuf[4] |= FIFOLOG_FLG_1BYTE;
199	} else {
200		be32enc(f->ff->recbuf + f->ff->recsize - 4,
201		    f->ff->zs->avail_out);
202		f->ff->recbuf[4] |= FIFOLOG_FLG_4BYTE;
203	}
204	i = pwrite(f->ff->fd, f->ff->recbuf, f->ff->recsize,
205		(f->recno + 1) * f->ff->recsize);
206	assert (i == (int)f->ff->recsize);
207	if (++f->recno == f->ff->logsize)
208		f->recno = 0;
209	f->cnt[FIFOLOG_PT_WRITES]++;
210	time(&t);
211	f->cnt[FIFOLOG_PT_RUNTIME] = t - f->starttime; /*lint !e776 */
212	fifolog_write_assert(f);
213}
214
215int
216fifolog_write_poll(struct fifolog_writer *f, time_t now)
217{
218	int i, fl, bo, bf;
219
220	if (now == 0)
221		time(&now);
222
223	fifolog_write_assert(f);
224	if (f->cleanup || now >= (int)(f->lastsync + f->syncrate)) {
225		/*
226		 * We always check the sync timer, otherwise a flood of data
227		 * would not get any sync records at all
228		 */
229		f->cleanup = 0;
230		fl = Z_FINISH;
231		f->lastsync = now;
232		f->lastwrite = now;
233		f->cnt[FIFOLOG_PT_SYNC]++;
234	} else if (f->ff->zs->avail_in == 0 &&
235	    now >= (int)(f->lastwrite + f->writerate)) {
236		/*
237		 * We only check for writerate timeouts when the input
238		 * buffer is empty.  It would be silly to force a write if
239		 * pending input could cause it to happen on its own.
240		 */
241		fl = Z_SYNC_FLUSH;
242		f->lastwrite = now;
243		f->cnt[FIFOLOG_PT_FLUSH]++;
244	} else if (f->ff->zs->avail_in == 0)
245		return (0);			/* nothing to do */
246	else
247		fl = Z_NO_FLUSH;
248
249	for (;;) {
250		assert(f->ff->zs->avail_out > 0);
251
252		bf = f->ff->zs->avail_out;
253
254		i = deflate(f->ff->zs, fl);
255		assert (i == Z_OK || i == Z_BUF_ERROR || i == Z_STREAM_END);
256
257		bo = f->ff->zs->avail_out;
258
259		/* If we have output space and not in a hurry.. */
260		if (bo > 0 && fl == Z_NO_FLUSH)
261			break;
262
263		/* Write output buffer, if anything in it */
264		if (bo != bf)
265			fifo_writerec(f);
266
267		/* If the buffer were full, we need to check again */
268		if (bo == 0) {
269			fifo_prepobuf(f, now, 0);
270			continue;
271		}
272
273		if (fl == Z_FINISH) {
274			/* Make next record a SYNC record */
275			fifo_prepobuf(f, now, 1);
276			/* And reset the zlib engine */
277			i = deflateReset(f->ff->zs);
278			assert(i == Z_OK);
279			f->writes_since_sync = 0;
280		} else {
281			fifo_prepobuf(f, now, 0);
282		}
283		break;
284	}
285
286	if (f->ff->zs->avail_in == 0) {
287		/* Reset input buffer when empty */
288		f->iptr = f->ibuf;
289		f->ff->zs->next_in = f->iptr;
290	}
291
292	fifolog_write_assert(f);
293	return (1);
294}
295
296static void
297fifolog_acct(struct fifolog_writer *f, unsigned bytes)
298{
299
300	f->ff->zs->avail_in += bytes;
301	f->iptr += bytes;
302	f->cnt[FIFOLOG_PT_BYTES_PRE] += bytes;
303}
304
305/*
306 * Attempt to write an entry.
307 * Return zero if there is no space, one otherwise
308 */
309
310int
311fifolog_write_bytes(struct fifolog_writer *f, uint32_t id, time_t now, const void *ptr, unsigned len)
312{
313	u_int l;
314	const unsigned char *p;
315
316	fifolog_write_assert(f);
317	assert(!(id & (FIFOLOG_TIMESTAMP|FIFOLOG_LENGTH)));
318	assert(ptr != NULL);
319
320	if (len == 0) {
321		len = strlen(ptr);
322		l = 4 + len;		/* id */
323		p = ptr;
324	} else {
325		assert(len <= 255);
326		p = ptr;
327		id |= FIFOLOG_LENGTH;
328		l = 5 + len;		/* id + len */
329	}
330
331	l += 4; 		/* A timestamp may be necessary */
332
333	/* Now do timestamp, if needed */
334	if (now == 0)
335		time(&now);
336
337	assert(l < f->ibufsize);
338
339	/* Wait until there is sufficient space without the lock */
340	if (f->iptr + l > f->ibuf + f->ibufsize)
341		return (0);
342
343	if (now != f->last) {
344		id |= FIFOLOG_TIMESTAMP;
345		f->last = now;
346	}
347
348	/* Emit instance+flag and length */
349	be32enc(f->iptr, id);
350	fifolog_acct(f, 4);
351
352	if (id & FIFOLOG_TIMESTAMP) {
353		be32enc(f->iptr, (uint32_t)f->last);
354		fifolog_acct(f, 4);
355	}
356	if (id & FIFOLOG_LENGTH) {
357		f->iptr[0] = (u_char)len;
358		fifolog_acct(f, 1);
359	}
360
361	assert (len > 0);
362	memcpy(f->iptr, p, len);
363	fifolog_acct(f, len);
364	fifolog_write_assert(f);
365	return (1);
366}
367
368/*
369 * Write an entry, polling until success.
370 * Long binary entries are broken into 255 byte chunks.
371 */
372
373void
374fifolog_write_bytes_poll(struct fifolog_writer *f, uint32_t id, time_t now, const void *ptr, unsigned len)
375{
376	u_int l;
377	const unsigned char *p;
378
379	fifolog_write_assert(f);
380
381	assert(!(id & (FIFOLOG_TIMESTAMP|FIFOLOG_LENGTH)));
382	assert(ptr != NULL);
383
384	if (len == 0) {
385		while (!fifolog_write_bytes(f, id, now, ptr, len)) {
386			(void)fifolog_write_poll(f, now);
387			(void)usleep(10000);
388		}
389	} else {
390		p = ptr;
391		for (p = ptr; len > 0; len -= l, p += l) {
392			l = len;
393			if (l > 255)
394				l = 255;
395			while (!fifolog_write_bytes(f, id, now, p, l)) {
396				(void)fifolog_write_poll(f, now);
397				(void)usleep(10000);
398			}
399		}
400	}
401	fifolog_write_assert(f);
402}
403
404int
405fifolog_write_flush(struct fifolog_writer *f)
406{
407	int i;
408
409	fifolog_write_assert(f);
410
411	f->cleanup = 1;
412	for (i = 0; fifolog_write_poll(f, 0); i = 1)
413		continue;
414	fifolog_write_assert(f);
415	return (i);
416}
417