text: /*-
   * Copyright (c) 2005-2008 Poul-Henning Kamp
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * $FreeBSD: soc2013/dpl/head/usr.sbin/fifolog/lib/fifolog_write_poll.c 219166 2011-03-01 08:52:10Z phk $
   */
  
  #include <assert.h>
  #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <stdint.h>
  #include <time.h>
  #include <sys/endian.h>
  
  #include <zlib.h>
  
  #include "fifolog.h"
  #include "libfifolog_int.h"
  #include "fifolog_write.h"
  #include "miniobj.h"
  
  static int fifolog_write_gzip(struct fifolog_writer *f, time_t now);
  
  #define ALLOC(ptr, size) do {                   \
  	(*(ptr)) = calloc(size, 1);             \
  	assert(*(ptr) != NULL);                 \
  } while (0)
  
  
  const char *fifolog_write_statnames[] = {
  	[FIFOLOG_PT_BYTES_PRE] =	"Bytes before compression",
  	[FIFOLOG_PT_BYTES_POST] =	"Bytes after compression",
  	[FIFOLOG_PT_WRITES] =		"Writes",
  	[FIFOLOG_PT_FLUSH] =		"Flushes",
  	[FIFOLOG_PT_SYNC] =		"Syncs",
  	[FIFOLOG_PT_RUNTIME] =		"Runtime"
  };
  
  /**********************************************************************
   * Check that everything is all right
   */
  static void
  fifolog_write_assert(const struct fifolog_writer *f)
  {
  
  	CHECK_OBJ_NOTNULL(f, FIFOLOG_WRITER_MAGIC);
  	assert(f->ff->zs->next_out + f->ff->zs->avail_out == \
  	    f->obuf + f->obufsize);
  }
  
  /**********************************************************************
   * Allocate/Destroy a new fifolog writer instance
   */
  
  struct fifolog_writer *
  fifolog_write_new(void)
  {
  	struct fifolog_writer *f;
  
  	ALLOC_OBJ(f, FIFOLOG_WRITER_MAGIC);
  	assert(f != NULL);
  	return (f);
  }
  
  void
  fifolog_write_destroy(struct fifolog_writer *f)
  {
  
  	free(f->obuf);
  	free(f->ibuf);
  	FREE_OBJ(f);
  }
  
  /**********************************************************************
   * Open/Close the fifolog
   */
  
  void
  fifolog_write_close(struct fifolog_writer *f)
  {
  	time_t now;
  
  	CHECK_OBJ_NOTNULL(f, FIFOLOG_WRITER_MAGIC);
  	fifolog_write_assert(f);
  
  	f->cleanup = 1;
  	time(&now);
  	fifolog_write_gzip(f, now);
  	fifolog_write_assert(f);
  	fifolog_int_close(&f->ff);
  	free(f->ff);
  }
  
  const char *
  fifolog_write_open(struct fifolog_writer *f, const char *fn,
      unsigned writerate, unsigned syncrate, unsigned compression)
  {
  	const char *es;
  	int i;
  	time_t now;
  	off_t o;
  
  	CHECK_OBJ_NOTNULL(f, FIFOLOG_WRITER_MAGIC);
  
  	/* Check for legal compression value */
  	if (compression > Z_BEST_COMPRESSION)
  		return ("Illegal compression value");
  
  	f->writerate = writerate;
  	f->syncrate = syncrate;
  	f->compression = compression;
  
  	/* Reset statistics */
  	memset(f->cnt, 0, sizeof f->cnt);
  
  	es = fifolog_int_open(&f->ff, fn, 1);
  	if (es != NULL)
  		return (es);
  	es = fifolog_int_findend(f->ff, &o);
  	if (es != NULL)
  		return (es);
  	i = fifolog_int_read(f->ff, o);
  	if (i)
  		return ("Read error, looking for seq");
  	f->seq = be32dec(f->ff->recbuf);
  	if (f->seq == 0) {
  		/* Empty fifolog */
  		f->seq = random();
  	} else {
  		f->recno = o + 1;
  		f->seq++;
  	}
  
  	f->obufsize = f->ff->recsize;
  	ALLOC(&f->obuf, f->obufsize);
  
  	f->ibufsize = f->obufsize * 10;
  	ALLOC(&f->ibuf, f->ibufsize);
  	f->ibufptr = 0;
  
  	i = deflateInit(f->ff->zs, (int)f->compression);
  	assert(i == Z_OK);
  
  	f->flag |= FIFOLOG_FLG_RESTART;
  	f->flag |= FIFOLOG_FLG_SYNC;
  	f->ff->zs->next_out = f->obuf + 9;
  	f->ff->zs->avail_out = f->obufsize - 9;
  
  	time(&now);
  	f->starttime = now;
  	f->lastsync = now;
  	f->lastwrite = now;
  
  	fifolog_write_assert(f);
  	return (NULL);
  }
  
  /**********************************************************************
   * Write an output record
   * Returns -1 if there are trouble writing data
   */
  
  static int
  fifolog_write_output(struct fifolog_writer *f, int fl, time_t now)
  {
  	long h, l = f->ff->zs->next_out - f->obuf;
  	ssize_t i, w;
  	int retval = 0;
  
  	h = 4;					/* seq */
  	be32enc(f->obuf, f->seq);
  	f->obuf[h] = f->flag;
  	h += 1;					/* flag */
  	if (f->flag & FIFOLOG_FLG_SYNC) {
  		be32enc(f->obuf + h, now);
  		h += 4;				/* timestamp */
  	}
  
  	assert(l <= (long)f->ff->recsize);	/* NB: l includes h */
  	assert(l >= h);
  
  	/* We will never write an entirely empty buffer */
  	if (l == h)
  		return (0);
  
  	if (l < (long)f->ff->recsize && fl == Z_NO_FLUSH)
  		return (0);
  
  	w = f->ff->recsize - l;
  	if (w >  255) {
  		be32enc(f->obuf + f->ff->recsize - 4, w);
  		f->obuf[4] |= FIFOLOG_FLG_4BYTE;
  	} else if (w > 0) {
  		f->obuf[f->ff->recsize - 1] = (uint8_t)w;
  		f->obuf[4] |= FIFOLOG_FLG_1BYTE;
  	}
  
  	f->cnt[FIFOLOG_PT_BYTES_POST] += l - h;
  
  	i = pwrite(f->ff->fd, f->obuf, f->ff->recsize,
  	    (f->recno + 1) * f->ff->recsize);
  	if (i != f->ff->recsize)
  		retval = -1;
  	else
  		retval = 1;
  
  	f->cnt[FIFOLOG_PT_WRITES]++;
  	f->cnt[FIFOLOG_PT_RUNTIME] = now - f->starttime;
  
  	f->lastwrite = now;
  	/*
  	 * We increment these even on error, so as to properly skip bad,
  	 * sectors or other light trouble.
  	 */
  	f->seq++;
  	f->recno++;
  	f->flag = 0;
  
  	memset(f->obuf, 0, f->obufsize);
  	f->ff->zs->next_out = f->obuf + 5;
  	f->ff->zs->avail_out = f->obufsize - 5;
  	return (retval);
  }
  
  /**********************************************************************
   * Run the compression engine
   * Returns -1 if there are trouble writing data
   */
  
  static int
  fifolog_write_gzip(struct fifolog_writer *f, time_t now)
  {
  	int i, fl, retval = 0;
  
  	assert(now != 0);
  	if (f->cleanup || now >= (int)(f->lastsync + f->syncrate)) {
  		f->cleanup = 0;
  		fl = Z_FINISH;
  		f->cnt[FIFOLOG_PT_SYNC]++;
  	} else if (now >= (int)(f->lastwrite + f->writerate)) {
  		fl = Z_SYNC_FLUSH;
  		f->cnt[FIFOLOG_PT_FLUSH]++;
  	} else if (f->ibufptr == 0)
  		return (0);
  	else
  		fl = Z_NO_FLUSH;
  
  	f->ff->zs->avail_in = f->ibufptr;
  	f->ff->zs->next_in = f->ibuf;
  
  	while (1) {
  		i = deflate(f->ff->zs, fl);
  		assert(i == Z_OK || i == Z_BUF_ERROR || i == Z_STREAM_END);
  
  		i = fifolog_write_output(f, fl, now);
  		if (i == 0)
  			break;
  		if (i < 0)
  			retval = -1;
  	}
  	assert(f->ff->zs->avail_in == 0);
  	f->ibufptr = 0;
  	if (fl == Z_FINISH) {
  		f->flag |= FIFOLOG_FLG_SYNC;
  		f->ff->zs->next_out = f->obuf + 9;
  		f->ff->zs->avail_out = f->obufsize - 9;
  		f->lastsync = now;
  		assert(Z_OK == deflateReset(f->ff->zs));
  	}
  	return (retval);
  }
  
  /**********************************************************************
   * Poll to see if we need to flush out a record
   * Returns -1 if there are trouble writing data
   */
  
  int
  fifolog_write_poll(struct fifolog_writer *f, time_t now)
  {
  
  	if (now == 0)
  		time(&now);
  	return (fifolog_write_gzip(f, now));
  }
  
  /**********************************************************************
   * Attempt to write an entry into the ibuf.
   * Return zero if there is no space, one otherwise
   */
  
  int
  fifolog_write_record(struct fifolog_writer *f, uint32_t id, time_t now,
      const void *ptr, ssize_t len)
  {
  	const unsigned char *p;
  	uint8_t buf[9];
  	ssize_t bufl;
  
  	fifolog_write_assert(f);
  	assert(!(id & (FIFOLOG_TIMESTAMP|FIFOLOG_LENGTH)));
  	assert(ptr != NULL);
  
  	p = ptr;
  	if (len == 0) {
  		len = strlen(ptr);
  		len++;
  	} else {
  		assert(len <= 255);
  		id |= FIFOLOG_LENGTH;
  	}
  	assert (len > 0);
  
  	/* Do a timestamp, if needed */
  	if (now == 0)
  		time(&now);
  
  	if (now != f->last)
  		id |= FIFOLOG_TIMESTAMP;
  
  	/* Emit instance+flag */
  	be32enc(buf, id);
  	bufl = 4;
  
  	if (id & FIFOLOG_TIMESTAMP) {
  		be32enc(buf + bufl, (uint32_t)now);
  		bufl += 4;
  	}
  	if (id & FIFOLOG_LENGTH)
  		buf[bufl++] = (u_char)len;
  
  	if (bufl + len + f->ibufptr > f->ibufsize)
  		return (0);
  
  	memcpy(f->ibuf + f->ibufptr, buf, bufl);
  	f->ibufptr += bufl;
  	memcpy(f->ibuf + f->ibufptr, p, len);
  	f->ibufptr += len;
  	f->cnt[FIFOLOG_PT_BYTES_PRE] += bufl + len;
  
  	if (id & FIFOLOG_TIMESTAMP)
  		f->last = now;
  	return (1);
  }
  
  /**********************************************************************
   * Write an entry, polling the gzip/writer until success.
   * Long binary entries are broken into 255 byte chunks.
   * Returns -1 if there are problems writing data
   */
  
  int
  fifolog_write_record_poll(struct fifolog_writer *f, uint32_t id, time_t now,
      const void *ptr, ssize_t len)
  {
  	u_int l;
  	const unsigned char *p;
  	int retval = 0;
  
  	if (now == 0)
  		time(&now);
  	fifolog_write_assert(f);
  
  	assert(!(id & (FIFOLOG_TIMESTAMP|FIFOLOG_LENGTH)));
  	assert(ptr != NULL);
  
  	if (len == 0) {
  		if (!fifolog_write_record(f, id, now, ptr, len)) {
  			if (fifolog_write_gzip(f, now) < 0)
  				retval = -1;
  			/* The string could be too long for the ibuf, so... */
  			if (!fifolog_write_record(f, id, now, ptr, len))
  				retval = -1;
  		}
  	} else {
  		for (p = ptr; len > 0; len -= l, p += l) {
  			l = len;
  			if (l > 255)
  				l = 255;
  			while (!fifolog_write_record(f, id, now, p, l))
  				if (fifolog_write_gzip(f, now) < 0)
  					retval = -1;
  		}
  	}
  	if (fifolog_write_gzip(f, now) < 0)
  		retval = -1;
  	fifolog_write_assert(f);
  	return (retval);
  }
  